WO2003055162A1 - System and method for reducing noise induced by digital subscriber line (dsl) systems into services that are concurrently deployed on a communication line - Google Patents

System and method for reducing noise induced by digital subscriber line (dsl) systems into services that are concurrently deployed on a communication line Download PDF

Info

Publication number
WO2003055162A1
WO2003055162A1 PCT/US2002/039460 US0239460W WO03055162A1 WO 2003055162 A1 WO2003055162 A1 WO 2003055162A1 US 0239460 W US0239460 W US 0239460W WO 03055162 A1 WO03055162 A1 WO 03055162A1
Authority
WO
WIPO (PCT)
Prior art keywords
approximately
khz
dbm
adaptively
dmt
Prior art date
Application number
PCT/US2002/039460
Other languages
French (fr)
Inventor
Patrick Duvaut
Ehud Langberg
William Scholtz
Laurent Pierrugues
Oliver Moreno
Original Assignee
Globespan Virata, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Globespan Virata, Inc. filed Critical Globespan Virata, Inc.
Priority to AU2002357134A priority Critical patent/AU2002357134A1/en
Publication of WO2003055162A1 publication Critical patent/WO2003055162A1/en

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00Data switching networks
    • H04L12/66Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • H04L27/2647Arrangements specific to the receiver only
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00Traffic control in data switching networks
    • H04L47/10Flow control; Congestion control
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00Traffic control in data switching networks
    • H04L47/10Flow control; Congestion control
    • H04L47/38Flow control; Congestion control by adapting coding or compression rate
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0044Arrangements for allocating sub-channels of the transmission path allocation of payload
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M11/00Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/06Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
    • H04M11/062Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors using different frequency bands for speech and other data
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q2213/00Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13039Asymmetrical two-way transmission, e.g. ADSL, HDSL
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q2213/00Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13176Common channel signaling, CCS7
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q2213/00Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/1319Amplifier, attenuation circuit, echo suppressor
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q2213/00Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13191Repeater
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q2213/00Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13209ISDN
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q2213/00Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13389LAN, internet

Definitions

  • 060706-1680 (EL 891429227 US), both mailed on December 10, 2002, are also incorporated herein by reference as if set forth in their entireties.
  • the present invention relates generally to data communication and, more particularly, to systems and methods for reducing noise induced by digital subscriber line (DSL) systems into services that are concurrently deployed on a communication line.
  • DSL digital subscriber line
  • DSL Digital subscriber line
  • POTS plain old telephone systems
  • TCM time compression multiplexing
  • ISDN integrated services digital network
  • POTS services and DSL services are deployed on non-overlapping portions of available bandwidth on the communication line. Thus, there is very little concern of cross-talk or other interference between POTS services and DSL services.
  • DSL and TCM-ISDN often share a portion of the available bandwidth, thereby making DSL services susceptible to cross-talk from TCM-ISDN services, and vice versa.
  • system requirements e.g., the degree of permissible disruption of TCM-ISDN service caused by DSL service
  • Japan may have a greater limitation than the United States on how much disruption is tolerable between concurrently-deployed services on the same line.
  • acceptable power levels for signal transmission in the United States may be unacceptable for signal transmission in Japan.
  • ITU-T G.992.2 Standardization Sector
  • DSL Digital Subscriber Line
  • FIGS. 1 through 4 show several static PSD masks defined by the ITU.
  • FIG. 1 is a diagram showing a static PSD mask for an asymmetric digital subscriber line transceiver unit at a central office (ATU-C) as defined by the ITU-T in Annex A of G.992.1 "Asymmetric Digital Subscriber Line (ADSL) Transceivers" (hereinafter "ITU-T G.992.1”) and G.992.2.
  • the static PSD mask is defined by a -97.5 dBm/Hz peak power in the POTS bandwidth; approximately f
  • FIG. 2 is a diagram showing a static PSD mask for reduced near-end cross talk (NEXT) for an ATU-C as defined by Annex A of G.992.1 and G.992.2. As shown in FIG. 2, the static PSD mask is defined by approximately -97.5 dBm Hz below
  • FIG. 3 is a diagram showing a static PSD mask for ADSL/Integrated Service Digital Network (ISDN) with 2-Binary-l -Quaternary (2B1Q) line coding as defined by Annex B of G.992.1 and G.992.2.
  • the static PSD mask is defined by a power level of approximately -90 dBm/Hz below approximately 50 kHz;
  • FIG. 4 is a diagram showing a static PSD mask for ADSL/ISDN with 4B3T line coding as defined by Annex B of G.992.1 and G.992.2. As shown in FIG. 4, the static PSD mask is' defined by a power level of approximately -90 dBm/Hz below
  • FIGS. 1 through 4 are configured for certain fixed line conditions. Thus, while the static PSD masks shown in FIGS. 1 through 4 may result in acceptable disruptions to TCM-ISDN services by the DSL services in one environment, these static PSD masks may result in unacceptable disruptions in other environments. Consequently, communication devices that are standards-compliant in one environment may not necessarily be standards-compliant in other environments. Given the potential incompatibility of communication devices in various environments, heretofore-unaddressed needs exist in the industry.
  • the present invention provides systems and methods for reducing noise induced by digital subscriber line (DSL) systems into services that are concurrently deployed on a communication line.
  • DSL digital subscriber line
  • one embodiment of the system comprises a receiver and logic configured to adaptively calculate a power level of a discrete multi- tone (DMT) sub-carrier.
  • the receiver is configured to receive signals from a communication line.
  • the signals are indicative of line conditions, which may be indicative of services deployed on the communication line.
  • the power level of the DMT sub-carrier may be adaptively calculated from the signals received from the communication line.
  • PSD power spectral density
  • Another embodiment of the system comprises an adaptively-filtered power spectral density (PSD) mask and logic configured to load DMT sub-carriers with data.
  • PSD power spectral density
  • the adaptively-filtered PSD mask has an attenuated portion that adaptively changes in response to line characteristics.
  • the DMT sub-carriers may be loaded in accordance with the adaptively-filtered PSD mask.
  • Yet another embodiment of the system comprises an adaptive filter and logic configured to allocate power to sub-carriers in a discrete multi-tone (DMT) modulated communication system.
  • the adaptive filter is configured to adaptively attenuate power within a portion of a power spectral density (PSD) mask to generate an adaptively- filtered PSD mask.
  • PSD power spectral density
  • the power allocated to the sub-carriers may be allocated in accordance with the adaptively-filtered PSD mask.
  • PSD power spectral density
  • the present invention can also be embodied as methods for reducing noise induced into services that are concurrently deployed on a communication line.
  • one embodiment ofthe method comprises the steps of receiving a signal from a communication line and adaptively determining a power level of a discrete multi-tone (DMT) sub-carrier in response to receiving the signal from the communication line.
  • the signal has information indicative of services deployed on the communication line.
  • FIG. 1 is a diagram showing a static power spectral density (PSD) mask for an asymmetric digital subscriber line transceiver unit at a central office (ATU-C) as defined by the Telecommunication Standardization Sector (ITU-T) of the International Telecommunication Union (ITU) in Annex A of G.992.1 "Asymmetric Digital Subscriber Line (ADSL) Transceivers” (hereinafter “G.992.1”) and G.992.2 “Splitterless Asymmetric Digital Subscriber Line (ADSL) Transceivers” (hereinafter "G.992.2”).
  • ITU-T Telecommunication Standardization Sector
  • ITU-T Telecommunication Standardization Sector
  • G.992.2 Splitterless Asymmetric Digital Subscriber Line
  • G.992.2 splitterless Asymmetric Digital Subscriber Line
  • FIG. 2 is a diagram showing a static PSD mask for reduced near-end cross talk (NEXT) for an ATU-C as defined by Annex A of G.992.1 and G.992.2.
  • NXT near-end cross talk
  • FIG. 3 is a diagram showing a static PSD mask for ADSL/Integrated Service Digital Network (ISDN) with 2-Binary-l -Quaternary (2B1Q) line coding as defined by Annex B of G.992.1 and G.992.2.
  • ISDN ADSL/Integrated Service Digital Network
  • 2B1Q 2-Binary-l -Quaternary
  • FIG. 4 is a diagram showing a static PSD mask for ADSL/ISDN with 4B3T line coding as defined by Annex B of G.992.1 and G.992.2.
  • FIG. 5 is a block diagram showing an example ADSL environment employing adaptively-filtered PSD masks.
  • FIG. 6 is a block diagram showing the ADSL modem of FIG. 5 in greater detail.
  • FIG. 7 is a block diagram showing logic components in the ATU-C of FIG. 6, which are configured to generate the adaptively-filtered PSD masks.
  • FIG. 8 is a diagram showing one embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • FIG. 9A is a diagram showing a transfer f-inction associated with one embodiment of the adaptive filter of FIG. 7, which has a variable attenuation over a variable frequency range.
  • FIG. 9B is a diagram showing a transfer function associated with one embodiment of the adaptive filter of FIG. 7, which has a variable attenuation over a fixed frequency range.
  • FIG. 9C is a diagram showing a transfer function associated with one embodiment of the adaptive filter of FIG. 7, which has a specific attenuation over a fixed frequency range.
  • FIG. 10 is a diagram showing another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • FIG. 11 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • FIG. 12 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation immediately above the plain old telephone system (POTS) bandwidth.
  • POTS plain old telephone system
  • FIG. 13 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation in a frequency bandwidth affected by integrated services digital network (ISDN) services.
  • ISDN integrated services digital network
  • FIG. 14 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation over a variable frequency range.
  • FIG. 15A is a diagram showing a transfer function associated with another embodiment of the adaptive filter of FIG. 7, which has a variable attenuation over a variable frequency range.
  • FIG. 15B is a diagram showing a transfer function associated with another embodiment of the adaptive filter of FIG. 7, which has a variable attenuation over a fixed frequency range.
  • FIG. 15C is a diagram showing a transfer function associated with another embodiment of the adaptive filter of FIG. 7, which has a specific attenuation over a fixed frequency range.
  • FIG. 15D is a diagram showing a transfer function associated with another embodiment of the adaptive filter of FIG. 7, which has a specific attenuation over a fixed frequency range.
  • FIG. 16 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • FIG. 17 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation in a frequency bandwidth affected by integrated services digital network (ISDN) services.
  • ISDN integrated services digital network
  • FIG. 18 is a diagram showing another embodiment of an adaptively-filtered PSD mask having a variable attenuation immediately above the POTS bandwidth.
  • FIG. 19 is a diagram showing another embodiment of an adaptively-filtered PSD mask having a variable attenuation immediately above the POTS bandwidth.
  • PSD mask having a variable attenuation in several non-adjacent bandwidths.
  • FIG. 20 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • FIG. 21 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • FIG. 22 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • FIG. 23 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • FIG. 24 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • FIG. 25 is a flowchart showing one embodiment of a method employing adaptively-filtered PSD masks.
  • feeder cables that radiate out of a central office to various customer premises are predominantly pulp-insulated.
  • Each feeder cable typically has approximately 400 two-conductor pair wires, and a large portion of the pulp-insulated two-conductor pair wires are used to service integrated services digital network (ISDN) subscribers.
  • ISDN integrated services digital network
  • the pulp insulation causes ADSL signal attenuation at higher frequencies, and adjacent ISDN signals cause significant levels of cross-talk interference.
  • the combination of attenuation and cross-talk reduces ADSL performance.
  • Annex C of the G.992.1 standard was developed to reduce adverse effects (e.g., attenuation and cross-talk)
  • the static power spectral density (PSD) masks often provide for sub-optimal data transmission.
  • FIGS. 5 through 25 illustrate various systems, methods, and power spectral density (PSD) masks, which are configured to reduce cross-talk between ADSL and ISDN while optimizing ADSL performance for systems similar to those found in Japan.
  • PSD power spectral density
  • Each of the embodiments maximizes downstream performance, balances upstream and downstream signal ratios, and provides spectral compatibility between ADSL and concurrently- deployed services (e.g., integrated services digital network (ISDN), plain old telephone systems (POTS), etc.).
  • ISDN integrated services digital network
  • POTS plain old telephone systems
  • the systems and methods are configured to determine the optimum data capacity given certain line conditions (e.g., signal-to-noise ratio (SNR), line attenuation, etc.).
  • SNR signal-to-noise ratio
  • the line conditions further provide information that permit the allocation of bandwidths and time slots for upstream and downstream signals, thereby balancing the upstream and downstream signal ratios. Additionally, since the line conditions provide information related to other concurrently-deployed services on the line, the systems and methods of FIGS. 5 through 25 also provide spectral compatibility between ADSL and other concurrently- deployed services.
  • the optimum conditions are predetermined as a function of government regulations, known or measured physical parameters, and other factors that are well known in the art. The data transmission parameters are then adjusted according to the predetermined optimum conditions.
  • FIG. 5 is a block diagram showing an example asymmetric digital subscriber line (ADSL) communication system 500 employing adaptively-filtered PSD masks.
  • ADSL digital subscriber line
  • the ADSL system is implemented between a central office 510 and a customer premise 560. Communication between the two sites 510, 560 takes place over a communication line 555 (also referred to as a local loop, twisted-pair cable, two-conductor pair wire, or channel).
  • the central office 510 end of the communication line 555 is configured to provide broadband services (e.g., video conferencing 515, Internet 520, telephone services 525, movies on demand 530, broadcast media 535, etc.), which are assembled via central office ADSL modems 550 for transmission over the communication line 555.
  • broadband services e.g., video conferencing 515, Internet 520, telephone services 525, movies on demand 530, broadcast media 535, etc.
  • the central office 510 assembles the signals from the broadband services at an ADSL service rack 540, which comprises a digital subscriber line access multiplexer (DSLAM) 545 and ADSL modems 550.
  • the central office 510 assembles the broadband services via the DSLAM 545 for appropriate transformation and transmission by one or more ADSL modems 550.
  • Each of he ADSL modems 550 may be in communication via a dedicated communication line 555 with a suitably configured ADSL modem 580 at a customer premise 560.
  • the DSLAM 545 and each of a plurality of ADSL modems 550 maybe assembled within an ADSL service rack 540 within the central office 510.
  • the ADSL commumcation system 500 presented in FIG. 5 is shown with a single ADSL service rack 540 for communicating each of the broadband services to n ADSL modems 550.
  • the ADSL service rack 540 may be configured to supply conditioned resources necessary to support the operation of the n ADSL modems 550.
  • Those skilled in the art will, appreciate the scalability of the ADSL communication system 500 generally presented in FIG. 5.
  • the central office 510 may be configured with a plurality of Transmission Control Protocol / Internet Protocol (TCP/IP) routers and Asynchronous Transfer Mode (ATM) switches (not shown) that may distribute one or more broadband service signals to a plurality of DSLAMs 545.
  • TCP/IP Transmission Control Protocol / Internet Protocol
  • ATM Asynchronous Transfer Mode
  • the plurality of DSLAMs 545 may further distribute the broadband service signals to a plurality of remotely located ADSL modems 580.
  • the customer premise 560 may be configured with a compatible ADSL modem 580, which may be configured to process and distribute the multiple broadband services to appropriate destination devices such as a computer 570, a television 575, and digital telephones 590 as illustrated.
  • the customer premise 560 may have plain old telephone systems (POTS) devices such as a facsimile machine 565 and an analog (POTS) telephone 585 integrated on the communication line 555 along with the ADSL modem 580. It is also feasible that the customer premise 560 may be replaced in some applications by another central office 510 or an ADSL repeater, where the POTS service may not be available or needed.
  • POTS plain old telephone systems
  • the customer premise 560 may be replaced in some applications by another central office 510 or an ADSL repeater, where the POTS service may not be available or needed.
  • FIG. 6 is a block diagram showing the ADSL modem 550 of FIG. 5 in greater detail. While FIG. 6 shows only one ADSL modem 550, it should be appreciated that each of the ADSL modems 550 of FIG. 5 may have similar components.
  • the ADSL modem 550 at the central office 510 comprises an ADSL transceiver unit (ATU-C) 605 configured to assemble data for transmission on the communication line 155.
  • the ATU-C 605 comprises both a fast path and an interleaved path between a multiplexer (MUX) and synchronization (sync) control block 610 and a tone ordering circuit 650.
  • MUX multiplexer
  • sync synchronization
  • the fast path which provides low latency, comprises a fast cyclic redundancy checking (CRC) block 615 and a scrambling and forward error correcting (FEC) block 625.
  • the interleaved path which provides a lower error rate at a greater latency, comprises an interleaved CRC block 620, a scrambling and FEC block 630, and an interleaver 640. Since MUX/sync control blocks 610, CRC blocks 615, 620, scrambling and FEC blocks 625, 630, interleavers 640, and tone ordering circuits 650 are known in the art, further discussion of these components is omitted here.
  • the signal upon traversing either the fast path or the interleaved path, enters an encoding and gain scaling block 655, which encodes the data into a constellation and also scales the data for transmission.
  • the encoding and gain scaling block 655 is discussed in greater detail with reference to FIG. 7.
  • EFT inverse Fourier transform
  • the IFT data is conveyed to a parallel-to-serial (P/S) converter 665, which converts the data into a serial data stream.
  • P/S parallel-to-serial
  • the serial data stream is conveyed to a digital-to-analog (D/A) converter and analog processor 670, which produces an analog signal for data transmission. Since IFT blocks 660, P/S converters 665, D/A converters and analog processors 670 are known in the art, further discussion of these components is omitted here.
  • the analog signal is transmitted through the communication line 555 by a transmitter 675 in the ATU-C 605.
  • FIG. 7 is a block diagram showing logic components in the encoding and gain scaling block 655 of FIG. 6, which is configured to encode and gain scale data according to adaptively-filtered PSD masks.
  • the encoder and gain sealer 655 comprises a receiver 710 and a processor 720.
  • the receiver 710 is configured to receive data from the tone-ordering circuit 650 as well as signals from the communication line 555.
  • the signals contain information related to line conditions, which, in turn, are indicative of services deployed on the communication line 555.
  • the signals from the communication line 555 comprise signal-to-noise ratio (SNR) information of the communication line 555, line attenuation information of the communication line 555, and information related to usable sub-carriers in the DMT modulated system.
  • SNR signal-to-noise ratio
  • the signals from the communication line 555 are updated for each data frame being encoded and gain scaled.
  • the encoder and gain sealer 655 is continuously updated with information on concurrently deployed services on the communication line 555
  • the processor 720 is configured to adaptively calculate a power level of the DMT sub-carriers in response to the signals received from the communication line 555.
  • the processor 720 comprises service determination logic 730, which adaptively determines services concurrently deployed on the communication line 555 In other words, if the received signal characteristics change and indicate that line conditions have changed, then the service determination logic 730 adaptively determines which services are deployed on the communication line 555 from the changes in line condition.
  • the processor 720 comprises power determination logic 740, which adaptively calculates an appropriate power level for each sub-carrier (or bin) once the services have been adaptively determined.
  • the power determination logic calculates sub-carrier power levels for each sub-carrier of each frame, which peraiits an optimization of power levels as a function of the determined services deployed on the communication line 555.
  • the processor 720 further comprises power allocation logic 750, which allocates the power to each sub-carrier as determined by the power determination logic 740.
  • the power allocation logic 750 comprises a power spectral density (PSD) mask 752 and an adaptive filter 754. Since the sub-carrier power levels may change from frame to frame due to potential changes in line conditions, a static PSD mask may not provide optimum sub-carrier power levels.
  • PSD power spectral density
  • the adaptive filter 754 adaptively alters the PSD mask 752 as a function of changing line conditions, thereby generating an adaptively-filtered PSD mask, which permits optimization of sub-carrier power levels as a function of changing line conditions.
  • the adaptive filter 754 is configured to selectively provide a fixed attenuation over a fixed frequency range. Thus, if all possible services concurrently deployed on the communication line 555 are known, then the adaptive filter 754 may selectively filter or not filter the PSD mask 752 as a function of the line conditions.
  • the adaptive filter 754 is configured to provide a variable attenuation over a fixed frequency range of between approximately 90 kHz and approximately 200 kHz.
  • the adaptive filter may variably attenuate the PSD mask 752 within the fixed frequency range as a function of the line conditions.
  • the variable attenuation may range from approximately 0 dB to approximately -12 dB. More specifically, in another embodiment, the variable attenuation may vary in a smaller range from approximately 0 dB to approximately -8 dB.
  • the adaptive filter 754 is configured to provide a variable attenuation over a different fixed frequency range.
  • the fixed frequency range is between approximately 4 kHz and approximately 26 kHz.
  • the adaptive filter 754, in another embodiment, is configured to provide a variable attenuation over a variable frequency range.
  • the adaptive filter may variably attenuate the PSD mask 752 over a variable frequency range as a function of the line conditions.
  • the variable frequency range may vary anywhere in the range of between approximately 90 kHz and approximately 200 kHz to accommodate services operating within that bandwidth.
  • variable frequency range may vary in a narrower frequency range of, for example, between approximately 121 kHz and approximately 164 kHz.
  • the 164 kHz frequency is the location of the peak of the first lobe of the TCM ISDN bandwidth
  • the 121 kHz frequency is the frequency at which downstream performance is optimized, upstream and downstream signals are balanced, and spectral compatibility between ADSL and concunently-deployed TCM ISDN services is optimized according to predefined conditions.
  • the variable frequency range may also be between approximately 4 kHz and approximately 200 kHz, which is the range immediately above the POTS bandwidth and the upper operating frequencies of ISDN.
  • the processor 720 also comprises data loading logic 760, which loads each of the sub-carriers.
  • data loading logic 760 loads the sub-carriers with data according to the adaptively-filtered PSD mask.
  • the data is loaded to each sub-carrier using an optimized power level as defined by the adaptively-filtered PSD mask.
  • FIGS. 8 through 24 show several transfer functions of adaptive filters 754 and several embodiments of adaptively-filtered PSD masks.
  • FIG. 8 is a diagram showing one embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. Specifically, FIG. 8 shows a portion of the G.992.1 Annex A PSD mask having approximately -12 dB attenuation between approximately 92.5 kHz and approximately 122.5 kHz. Thus, rather than having a uniform peak power of approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 1104 kHz like the prior-art Annex A PSD mask of FIG. 1, the adaptively-filtered PSD mask of FIG. 8 has an approximately -12 dB attenuation "notch" between approximately 92.5 kHz and approximately 122.5 kHz. The "notch" reduces the power allocated to the frequency range defined by the "notch," thereby concomitantly reducing any cross-talk that the DSL service may induce into other services deployed on the communication line 555 within that frequency range.
  • FIG. 9A is a diagram showing a transfer function associated with one embodiment ofthe adaptive filter 754 of FIG. 7, which has a variable attenuation over a variable frequency range.
  • FIG. 9A shows a general adaptive filter 754 in which the attenuation bandwidth may be adaptively changed in response to detected line conditions.
  • one embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a
  • FIG. 9B is a diagram showing a transfer function associated with one embodiment ofthe adaptive filter 754 of FIG. 7, which has a variable attenuation over a fixed frequency range. As shown in FIG. 9B, this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation
  • -A ⁇ , -A 2 , and -A 5 are attenuation values that are adaptively set in response to detected line conditions.
  • FIG. 9C is a diagram showing a transfer function associated with one embodiment ofthe adaptive filter 754 of FIG. 7, which has a specific attenuation over a fixed frequency range. As shown in FIG. 9B, this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation
  • the processor 720 may selectively apply or not apply the notch filter to a PSD mask depending on the presence or absence of other services on the communication line 555, as indicated by the detected line conditions.
  • FIG. 10 is a diagram showing another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. As shown in FIG. 10, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below
  • FIG. 10 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility in Annex A and Annex C far-end cross-talk (FEXT) bit-mapped (FBM) systems. Since Annex A and Annex C are well known and, also, are described in the G.992.1 standard, further discussion of Annex A and Annex C is omitted here.
  • FIG. 11 is a diagram showing yet another embodiment of an adaptively-filtered
  • the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below
  • the PSD mask shown in FIG. 11 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility in Annex A FBM systems.
  • FIG. 12 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation immediately above the plain old telephone system (POTS) bandwidth.
  • the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a
  • FIG. 13 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask having a variable attenuation between approximately 121 kHz and 164 kHz.
  • the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately
  • FIG. 14 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation over a plurality of different frequency ranges.
  • the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a variable attenuation of
  • FIG. 15 A is a diagram showing a transfer function associated with another embodiment ofthe adaptive filter 754 of FIG. 7, which has a variable attenuation over a variable frequency range.
  • FIG. 15A shows a general adaptive filter 754 in which the attenuation bandwidth may be adaptively changed in response to detected line conditions. As shown in FIG.
  • one embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a frequency of/i; -4 3 dBm/Hz attenuation between f and/ 5 ; and 0 dBm/Hz attenuation above ⁇ , where -_4 3 is an attenuation value that is adaptively set in response to detected line conditions, and fc and fs are frequencies that are adaptively set in response to detected line conditions.
  • FIG. 15B is a diagram showing a transfer function associated with another embodiment ofthe adaptive filter 754 of FIG. 7, which has a variable attenuation over a fixed frequency range.
  • this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a frequency of approximately 100 kHz; -A 3 dBm/Hz attenuation between approximately 100 kHz and approximately 200 kHz; and 0 dBm/Hz attenuation above approximately 200 kHz, where -A 3 is an attenuation value that is adaptively set in response to detected line conditions.
  • FIG. 15C is a diagram showing a transfer function associated with another embodiment ofthe adaptive filter 754 of FIG. 7, which has a specific attenuation over a fixed frequency range.
  • this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a frequency of approximately 100 kHz; approximately -8 dBm/Hz attenuation between approximately 100 kHz and approximately 200 kHz; and 0 dBm/Hz attenuation above approximately 200 kHz.
  • FIG. 15D is a diagram showing a transfer function associated with another embodiment ofthe adaptive filter 754 of FIG. 7, which has a specific attenuation over a fixed frequency range. As shown in FIG.
  • this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a frequency of approximately 100 kHz; approximately -12 dBm/Hz attenuation between approximately 100 kHz and approximately 200 kHz; and 0 dBm/Hz attenuation above approximately 200 kHz.
  • FIG. 16 is a diagram showing yet another embodiment of an adaptively-filtered
  • the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below
  • FIG. 17 is a diagram showing another embodiment of an adaptively-filtered PSD mask having a variable attenuation within a variable frequency range.
  • the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a variable attenuation of
  • FIG. 18 is a diagram showing another embodiment of an adaptively-filtered
  • the adaptively-filtered PSD mask having a variable attenuation immediately above the POTS bandwidth.
  • the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a variable attenuation of
  • FIG. 19 is a diagram showing another embodiment of an adaptively-filtered PSD mask having a variable attenuation in several non-adjacent bandwidths.
  • the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a variable attenuation of 97.5 + 4 x ( between approximately 4 kHz and approximately 26 kHz;
  • FIG. 20 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. As shown in FIG. 20, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -94.5 dBm/Hz between approximately 4 kHz and
  • the PSD mask shown in FIG. 20 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a near-end cross-talk (NEXT) period in extended reach Annex C systems adapted for time-frequency division duplexing. Since Annex C systems are known in the art and, also, are described in G.992.1, further discussion of Annex C systems and their requirements is omitted here.
  • NXT near-end cross-talk
  • FIG. 21 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -94.5 dBm/Hz between approximately 4 kHz and
  • the PSD mask shown in FIG. 21 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a far-end cross-talk (FEXT) period in extended reach Annex C systems adapted for time-frequency division duplexing.
  • FXT far-end cross-talk
  • FIG. 22 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -86.5 dBm/Hz between approximately 4 kHz and
  • the PSD mask shown in FIG. 22 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a far-end cross-talk (FEXT) period in FEXT bit-mapped (FBM) Annex C systems.
  • FEXT far-end cross-talk
  • FBM bit-mapped
  • FIG. 23 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. As shown in FIG. 23, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm Hz below
  • the PSD mask shown in FIG. 23 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a far-end cross-talk (FEXT) period in Annex C systems adapted for time-frequency division duplexing.
  • FXT far-end cross-talk
  • FIG. 24 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
  • the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -94.5 dBm/Hz between approximately 4 kHz and
  • the PSD mask shown in FIG. 24 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a near-end cross-talk (NEXT) period in Annex C systems adapted for time- frequency division duplexing.
  • NXT near-end cross-talk
  • FIG. 25 is a flowchart showing one embodiment of a method employing adaptively-filtered PSD masks.
  • a DMT-modulated communication system receives (2520) a signal from a communication line 555.
  • the received (2520) signal has information indicative of services deployed on the communication line 555.
  • the received (2520) signal contains information related to line conditions.
  • the DMT-modulated communications system Upon receiving (2520) the signal, the DMT-modulated communications system adaptively determines (2530) a power level of a DMT sub-carrier. Additionally, the DMT-modulated communication system adaptively attenuates (2540) power within a portion of a PSD mask using the adaptively determined (2530) power level of the DMT sub-carrier.
  • the DMT sub-carrier is loaded (2550) with data according to the adaptively determined (2530) power level.
  • the method of FIG. 25 may be performed by the systems described with reference to FIGS. 5 through 24. However, it should be understood that other communication systems employing DMT modulation might also perform the steps described with reference to FIG. 25.
  • the service determination logic 730, the power determination logic 740, the power allocation logic 750, and the data loading logic 760 ofthe present invention can be implemented in hardware, software, firmware, or a combination thereof.
  • the service determination logic 730, the power determination logic 740, the power allocation logic 750, and the data loading logic 760 is implemented in hardware using any or a combination of the following technologies, which are all well known in the art: a discrete logic circuit(s) having logic gates for implementing logic functions upon data signals, an application specific integrated circuit (ASIC) having appropriate combinational logic gates, a programmable gate array(s) (PGA), a field programmable gate anay (FPGA), etc.
  • the service determination logic 730, the power determination logic 740, the power allocation logic 750, and the data loading logic 760 is implemented in software or firmware that is stored in a memory and that is executed by a suitable instruction execution system.
  • processor and logic configured to adaptively calculate the DMT sub-carrier power level are shown within the encoding and gain scaling block, it should be appreciated that the processor and logic configured to adaptively calculate the DMT sub-carrier power level may also be located as a separate unit outside of the encoding and gain scaling block.

Abstract

Systems and methods are presented for reducing noise induced by digital subscriber line (DSL) systems into services that are concurrently deployed on a communication line. In the disclosed technique, a power level of a discrete multi-tone (DMT) sub-carrier is adaptively calculated (2530) from a signal that is received from a communication line (2520). The signal has information indicative of line conditions, which are further indicative of services deployed on the communication line.

Description

SYSTEM AND METHOD FOR REDUCING NOISE INDUCED
BY DIGITAL SUBSCRIBER LINE (DSL) SYSTEMS INTO SERVICES THAT ARE CONCURRENTLY DEPLOYED ON A COMMUNICATION LINE
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. provisional patent application serial numbers 60/338,939, dated December 10, 2001; 60/341,654, dated December 16, 2001;
60/346,809, dated January 7, 2002; 60/348,575, dated January 14, 2002; 60/350,552, dated January 22, 2002; 60/353,880, dated February 2, 2002; 60/354,888, dated
February 6, 2002; and 60/355,117, dated February 8, 2002. These U. S. provisional patent applications are incorporated herein by reference as if set forth in their entireties.
Co-pending U.S. patent applications 060706-1550 (EL 891429200 US) and
060706-1680 (EL 891429227 US), both mailed on December 10, 2002, are also incorporated herein by reference as if set forth in their entireties.
FIELD OF INVENTION
The present invention relates generally to data communication and, more particularly, to systems and methods for reducing noise induced by digital subscriber line (DSL) systems into services that are concurrently deployed on a communication line.
BACKGROUND
Industries related to modern communication systems have experienced a tremendous growth due to the increasing popularity of the Internet. Digital subscriber line (DSL) technology is one technology that has developed in recent years in response to the demand for high-speed Internet access. DSL technology uses a communication line of a pre-existing telephone system as the backbone for the DSL lines. Thus, both plain old telephone systems (POTS) and DSL systems share a common line for DSL- compatible customer premises. Similarly, other services such as time compression multiplexing (TCM) integrated services digital network (ISDN) can also share a common line with DSL and POTS.
POTS services and DSL services are deployed on non-overlapping portions of available bandwidth on the communication line. Thus, there is very little concern of cross-talk or other interference between POTS services and DSL services. However, DSL and TCM-ISDN often share a portion of the available bandwidth, thereby making DSL services susceptible to cross-talk from TCM-ISDN services, and vice versa.
To compound problems even further, system requirements (e.g., the degree of permissible disruption of TCM-ISDN service caused by DSL service) may vary greatly from country to country. For example, Japan may have a greater limitation than the United States on how much disruption is tolerable between concurrently-deployed services on the same line. Thus, acceptable power levels for signal transmission in the United States may be unacceptable for signal transmission in Japan.
Certain standards committees, such as the International Telecommunication Union - Telecommunication Standardization Sector (ITU-T), have provided standards documents for deployment of DSL, such as G.992.2, "Splitterless Asymmetric Digital Subscriber Line (ADSL) Transceivers" (hereinafter "ITU-T G.992.2"), published in June of 1999. These standards documents provide static power spectral density (PSD) masks that limit the amount of power allocated to the DSL bandwidth, thereby limiting the amount of cross-talk induced by the DSL system on other services concurrently deployed on the same line. For example, FIGS. 1 through 4 show several static PSD masks defined by the ITU. FIG. 1 is a diagram showing a static PSD mask for an asymmetric digital subscriber line transceiver unit at a central office (ATU-C) as defined by the ITU-T in Annex A of G.992.1 "Asymmetric Digital Subscriber Line (ADSL) Transceivers" (hereinafter "ITU-T G.992.1") and G.992.2. As shown in FIG. 1, the static PSD mask is defined by a -97.5 dBm/Hz peak power in the POTS bandwidth; approximately f
92.5 + 2lx log2 f dBm/Hz between approximately 4 kHz and approximately 26 4
kHz; approximately -36.5 dBm/Hz between approximately 26 kHz and approximately
1104 kHz; approximately 36.5 - 36 x log - between approximately 1104
Figure imgf000005_0001
kHz and approximately 3093 kHz; and approximately -90 dBm Hz above approximately 3093 kHz.
FIG. 2 is a diagram showing a static PSD mask for reduced near-end cross talk (NEXT) for an ATU-C as defined by Annex A of G.992.1 and G.992.2. As shown in FIG. 2, the static PSD mask is defined by approximately -97.5 dBm Hz below
approximately 4 kHz; approximately dBm/Hz between
Figure imgf000005_0002
approximately 4 kHz and approximately 80 kHz; approximately
- dBm/Hz between approximately 80 kHz and approximately
Figure imgf000005_0003
138 kHz; approximately -36.5 dBm/Hz between approximately 138 kHz and
approximately 1104 kHz; approximately -36.5 between
Figure imgf000005_0004
approximately 1104 kHz and approximately 3093 kHz; approximately -90 dBm/Hz between approximately 3093 kHz and approximately 4545 kHz; and approximately -50 dBm/Hz power in any 1 MHz sliding window between approximately 4545 kHz and approximately 11040 kHz.
FIG. 3 is a diagram showing a static PSD mask for ADSL/Integrated Service Digital Network (ISDN) with 2-Binary-l -Quaternary (2B1Q) line coding as defined by Annex B of G.992.1 and G.992.2. As shown in FIG. 3, the static PSD mask is defined by a power level of approximately -90 dBm/Hz below approximately 50 kHz;
approximately 90 dBm/Hz between approximately 50 kHz and
Figure imgf000006_0001
approximately 80 kHz; low-pass and high-pass filter-design-dependent power level between approximately 80 kHz and approximately 138 kHz; approximately -36.5 dBm/Hz between approximately 138 kHz and approximately 1104 kHz; approximately
36.5 - 36 x log. between approximately 1104 kHz and approximately 3093
Figure imgf000006_0002
kHz; approximately -90 dBm/Hz between approximately 3093 kHz and approximately 4545 kHz; and approximately -50 dBm/Hz power in any 1 MHz sliding window between approximately 4545 kHz and approximately 11040 kHz.
FIG. 4 is a diagram showing a static PSD mask for ADSL/ISDN with 4B3T line coding as defined by Annex B of G.992.1 and G.992.2. As shown in FIG. 4, the static PSD mask is' defined by a power level of approximately -90 dBm/Hz below
approximately 70 kHz; approximately dBm/Hz between
Figure imgf000006_0003
approximately 70 kHz and approximately 90 kHz; low-pass and high-pass filter-design- dependent power level between approximately 90 kHz and approximately 138 kHz; approximately -36.5 dBm/Hz between approximately 138 kHz and approximately 1104
kHz; approximately — 36.5 - 36 Y. between approximately 1104 kHz and
Figure imgf000006_0004
approximately 3093 kHz; approximately -90 dBm Hz between approximately 3093 kHz and approximately 4545 kHz; and approximately -50 dBm/Hz power in any 1 MHz sliding window between approximately 4545 kHz and approximately 11040 kHz. The various static PSD masks of FIGS. 1 through 4 are configured for certain fixed line conditions. Thus, while the static PSD masks shown in FIGS. 1 through 4 may result in acceptable disruptions to TCM-ISDN services by the DSL services in one environment, these static PSD masks may result in unacceptable disruptions in other environments. Consequently, communication devices that are standards-compliant in one environment may not necessarily be standards-compliant in other environments. Given the potential incompatibility of communication devices in various environments, heretofore-unaddressed needs exist in the industry.
SUMMARY
The present invention provides systems and methods for reducing noise induced by digital subscriber line (DSL) systems into services that are concurrently deployed on a communication line.
Briefly described, in architecture, one embodiment of the system comprises a receiver and logic configured to adaptively calculate a power level of a discrete multi- tone (DMT) sub-carrier. The receiver is configured to receive signals from a communication line. The signals are indicative of line conditions, which may be indicative of services deployed on the communication line. The power level of the DMT sub-carrier may be adaptively calculated from the signals received from the communication line.
Another embodiment of the system comprises an adaptively-filtered power spectral density (PSD) mask and logic configured to load DMT sub-carriers with data. The adaptively-filtered PSD mask has an attenuated portion that adaptively changes in response to line characteristics. The DMT sub-carriers may be loaded in accordance with the adaptively-filtered PSD mask.
Yet another embodiment of the system comprises an adaptive filter and logic configured to allocate power to sub-carriers in a discrete multi-tone (DMT) modulated communication system. The adaptive filter is configured to adaptively attenuate power within a portion of a power spectral density (PSD) mask to generate an adaptively- filtered PSD mask. The power allocated to the sub-carriers may be allocated in accordance with the adaptively-filtered PSD mask. The present invention can also be embodied as methods for reducing noise induced into services that are concurrently deployed on a communication line. In this regard, one embodiment ofthe method comprises the steps of receiving a signal from a communication line and adaptively determining a power level of a discrete multi-tone (DMT) sub-carrier in response to receiving the signal from the communication line. In one embodiment, the signal has information indicative of services deployed on the communication line.
Other systems, methods, features, and advantages of the present invention will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be mcluded within this description, be within the scope ofthe present invention, and be protected by the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
FIG. 1 is a diagram showing a static power spectral density (PSD) mask for an asymmetric digital subscriber line transceiver unit at a central office (ATU-C) as defined by the Telecommunication Standardization Sector (ITU-T) of the International Telecommunication Union (ITU) in Annex A of G.992.1 "Asymmetric Digital Subscriber Line (ADSL) Transceivers" (hereinafter "G.992.1") and G.992.2 "Splitterless Asymmetric Digital Subscriber Line (ADSL) Transceivers" (hereinafter "G.992.2").
FIG. 2 is a diagram showing a static PSD mask for reduced near-end cross talk (NEXT) for an ATU-C as defined by Annex A of G.992.1 and G.992.2.
FIG. 3 is a diagram showing a static PSD mask for ADSL/Integrated Service Digital Network (ISDN) with 2-Binary-l -Quaternary (2B1Q) line coding as defined by Annex B of G.992.1 and G.992.2.
FIG. 4 is a diagram showing a static PSD mask for ADSL/ISDN with 4B3T line coding as defined by Annex B of G.992.1 and G.992.2.
FIG. 5 is a block diagram showing an example ADSL environment employing adaptively-filtered PSD masks.
FIG. 6 is a block diagram showing the ADSL modem of FIG. 5 in greater detail. FIG. 7 is a block diagram showing logic components in the ATU-C of FIG. 6, which are configured to generate the adaptively-filtered PSD masks. FIG. 8 is a diagram showing one embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
FIG. 9A is a diagram showing a transfer f-inction associated with one embodiment of the adaptive filter of FIG. 7, which has a variable attenuation over a variable frequency range.
FIG. 9B is a diagram showing a transfer function associated with one embodiment of the adaptive filter of FIG. 7, which has a variable attenuation over a fixed frequency range.
FIG. 9C is a diagram showing a transfer function associated with one embodiment of the adaptive filter of FIG. 7, which has a specific attenuation over a fixed frequency range.
FIG. 10 is a diagram showing another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
FIG. 11 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
FIG. 12 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation immediately above the plain old telephone system (POTS) bandwidth.
FIG. 13 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation in a frequency bandwidth affected by integrated services digital network (ISDN) services.
FIG. 14 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation over a variable frequency range. FIG. 15A is a diagram showing a transfer function associated with another embodiment of the adaptive filter of FIG. 7, which has a variable attenuation over a variable frequency range.
FIG. 15B is a diagram showing a transfer function associated with another embodiment of the adaptive filter of FIG. 7, which has a variable attenuation over a fixed frequency range.
FIG. 15C is a diagram showing a transfer function associated with another embodiment of the adaptive filter of FIG. 7, which has a specific attenuation over a fixed frequency range. FIG. 15D is a diagram showing a transfer function associated with another embodiment of the adaptive filter of FIG. 7, which has a specific attenuation over a fixed frequency range.
FIG. 16 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. FIG. 17 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation in a frequency bandwidth affected by integrated services digital network (ISDN) services.
FIG. 18 is a diagram showing another embodiment of an adaptively-filtered PSD mask having a variable attenuation immediately above the POTS bandwidth. FIG. 19 is a diagram showing another embodiment of an adaptively-filtered
PSD mask having a variable attenuation in several non-adjacent bandwidths.
FIG. 20 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
FIG. 21 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. FIG. 22 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7.
FIG. 23 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. FIG. 24 is a diagram showing yet another embodiment of an adaptively-filtered
PSD mask generated by the system of FIG. 7.
FIG. 25 is a flowchart showing one embodiment of a method employing adaptively-filtered PSD masks.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Having summarized various aspects of the present invention, reference is no made in detail to the description of the embodiments as illustrated in the drawings. While several embodiments are described in connection with these drawings, there is no intent to limit the invention to the embodiment or embodiments disclosed herein. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope ofthe invention as defined by the appended claims.
In Japan, for example, feeder cables that radiate out of a central office to various customer premises are predominantly pulp-insulated. Each feeder cable typically has approximately 400 two-conductor pair wires, and a large portion of the pulp-insulated two-conductor pair wires are used to service integrated services digital network (ISDN) subscribers. Thus, when ADSL signals are present, the pulp insulation causes ADSL signal attenuation at higher frequencies, and adjacent ISDN signals cause significant levels of cross-talk interference. The combination of attenuation and cross-talk reduces ADSL performance. While Annex C of the G.992.1 standard was developed to reduce adverse effects (e.g., attenuation and cross-talk), the static power spectral density (PSD) masks often provide for sub-optimal data transmission.
FIGS. 5 through 25 illustrate various systems, methods, and power spectral density (PSD) masks, which are configured to reduce cross-talk between ADSL and ISDN while optimizing ADSL performance for systems similar to those found in Japan. Each of the embodiments maximizes downstream performance, balances upstream and downstream signal ratios, and provides spectral compatibility between ADSL and concurrently- deployed services (e.g., integrated services digital network (ISDN), plain old telephone systems (POTS), etc.). In maximizing downstream performance, the systems and methods are configured to determine the optimum data capacity given certain line conditions (e.g., signal-to-noise ratio (SNR), line attenuation, etc.). The line conditions further provide information that permit the allocation of bandwidths and time slots for upstream and downstream signals, thereby balancing the upstream and downstream signal ratios. Additionally, since the line conditions provide information related to other concurrently-deployed services on the line, the systems and methods of FIGS. 5 through 25 also provide spectral compatibility between ADSL and other concurrently- deployed services. The optimum conditions are predetermined as a function of government regulations, known or measured physical parameters, and other factors that are well known in the art. The data transmission parameters are then adjusted according to the predetermined optimum conditions.
FIG. 5 is a block diagram showing an example asymmetric digital subscriber line (ADSL) communication system 500 employing adaptively-filtered PSD masks. Generally, the ADSL system is implemented between a central office 510 and a customer premise 560. Communication between the two sites 510, 560 takes place over a communication line 555 (also referred to as a local loop, twisted-pair cable, two-conductor pair wire, or channel). The central office 510 end of the communication line 555 is configured to provide broadband services (e.g., video conferencing 515, Internet 520, telephone services 525, movies on demand 530, broadcast media 535, etc.), which are assembled via central office ADSL modems 550 for transmission over the communication line 555. The central office 510 assembles the signals from the broadband services at an ADSL service rack 540, which comprises a digital subscriber line access multiplexer (DSLAM) 545 and ADSL modems 550. The central office 510 assembles the broadband services via the DSLAM 545 for appropriate transformation and transmission by one or more ADSL modems 550. Each of he ADSL modems 550 may be in communication via a dedicated communication line 555 with a suitably configured ADSL modem 580 at a customer premise 560.
As illustrated in FIG. 5, the DSLAM 545 and each of a plurality of ADSL modems 550 maybe assembled within an ADSL service rack 540 within the central office 510. For simplicity of illustration and explanation, the ADSL commumcation system 500 presented in FIG. 5 is shown with a single ADSL service rack 540 for communicating each of the broadband services to n ADSL modems 550. The ADSL service rack 540 may be configured to supply conditioned resources necessary to support the operation of the n ADSL modems 550. Those skilled in the art will, appreciate the scalability of the ADSL communication system 500 generally presented in FIG. 5. For example, the central office 510 may be configured with a plurality of Transmission Control Protocol / Internet Protocol (TCP/IP) routers and Asynchronous Transfer Mode (ATM) switches (not shown) that may distribute one or more broadband service signals to a plurality of DSLAMs 545. In turn, the plurality of DSLAMs 545 may further distribute the broadband service signals to a plurality of remotely located ADSL modems 580. At the opposite end of the communication line 555, the customer premise 560 may be configured with a compatible ADSL modem 580, which may be configured to process and distribute the multiple broadband services to appropriate destination devices such as a computer 570, a television 575, and digital telephones 590 as illustrated. It is significant to note that that the customer premise 560 may have plain old telephone systems (POTS) devices such as a facsimile machine 565 and an analog (POTS) telephone 585 integrated on the communication line 555 along with the ADSL modem 580. It is also feasible that the customer premise 560 may be replaced in some applications by another central office 510 or an ADSL repeater, where the POTS service may not be available or needed.
FIG. 6 is a block diagram showing the ADSL modem 550 of FIG. 5 in greater detail. While FIG. 6 shows only one ADSL modem 550, it should be appreciated that each of the ADSL modems 550 of FIG. 5 may have similar components. As shown in FIG. 6, the ADSL modem 550 at the central office 510 comprises an ADSL transceiver unit (ATU-C) 605 configured to assemble data for transmission on the communication line 155. In this regard, the ATU-C 605 comprises both a fast path and an interleaved path between a multiplexer (MUX) and synchronization (sync) control block 610 and a tone ordering circuit 650. The fast path, which provides low latency, comprises a fast cyclic redundancy checking (CRC) block 615 and a scrambling and forward error correcting (FEC) block 625. The interleaved path, which provides a lower error rate at a greater latency, comprises an interleaved CRC block 620, a scrambling and FEC block 630, and an interleaver 640. Since MUX/sync control blocks 610, CRC blocks 615, 620, scrambling and FEC blocks 625, 630, interleavers 640, and tone ordering circuits 650 are known in the art, further discussion of these components is omitted here. However, it should be appreciated that the signal, upon traversing either the fast path or the interleaved path, enters an encoding and gain scaling block 655, which encodes the data into a constellation and also scales the data for transmission. The encoding and gain scaling block 655 is discussed in greater detail with reference to FIG. 7. Once the data has been encoded and gain-scaled, the data is relayed in parallel blocks to an inverse Fourier transform (EFT) block 660, which performs a IFT on the parallel data blocks. The IFT data is conveyed to a parallel-to-serial (P/S) converter 665, which converts the data into a serial data stream. The serial data stream is conveyed to a digital-to-analog (D/A) converter and analog processor 670, which produces an analog signal for data transmission. Since IFT blocks 660, P/S converters 665, D/A converters and analog processors 670 are known in the art, further discussion of these components is omitted here. The analog signal is transmitted through the communication line 555 by a transmitter 675 in the ATU-C 605.
FIG. 7 is a block diagram showing logic components in the encoding and gain scaling block 655 of FIG. 6, which is configured to encode and gain scale data according to adaptively-filtered PSD masks. As shown in FIG. 7, the encoder and gain sealer 655 comprises a receiver 710 and a processor 720. The receiver 710 is configured to receive data from the tone-ordering circuit 650 as well as signals from the communication line 555. The signals contain information related to line conditions, which, in turn, are indicative of services deployed on the communication line 555. The signals from the communication line 555 comprise signal-to-noise ratio (SNR) information of the communication line 555, line attenuation information of the communication line 555, and information related to usable sub-carriers in the DMT modulated system. The signals from the communication line 555 are updated for each data frame being encoded and gain scaled. Thus, the encoder and gain sealer 655 is continuously updated with information on concurrently deployed services on the communication line 555.
The processor 720 is configured to adaptively calculate a power level of the DMT sub-carriers in response to the signals received from the communication line 555. In this regard, the processor 720 comprises service determination logic 730, which adaptively determines services concurrently deployed on the communication line 555 In other words, if the received signal characteristics change and indicate that line conditions have changed, then the service determination logic 730 adaptively determines which services are deployed on the communication line 555 from the changes in line condition.
Additionally, the processor 720 comprises power determination logic 740, which adaptively calculates an appropriate power level for each sub-carrier (or bin) once the services have been adaptively determined. In this regard, the power determination logic calculates sub-carrier power levels for each sub-carrier of each frame, which peraiits an optimization of power levels as a function of the determined services deployed on the communication line 555.
The processor 720 further comprises power allocation logic 750, which allocates the power to each sub-carrier as determined by the power determination logic 740. The power allocation logic 750 comprises a power spectral density (PSD) mask 752 and an adaptive filter 754. Since the sub-carrier power levels may change from frame to frame due to potential changes in line conditions, a static PSD mask may not provide optimum sub-carrier power levels. The adaptive filter 754 adaptively alters the PSD mask 752 as a function of changing line conditions, thereby generating an adaptively-filtered PSD mask, which permits optimization of sub-carrier power levels as a function of changing line conditions. In one embodiment, the adaptive filter 754 is configured to selectively provide a fixed attenuation over a fixed frequency range. Thus, if all possible services concurrently deployed on the communication line 555 are known, then the adaptive filter 754 may selectively filter or not filter the PSD mask 752 as a function of the line conditions.
In another embodiment, the adaptive filter 754 is configured to provide a variable attenuation over a fixed frequency range of between approximately 90 kHz and approximately 200 kHz. Thus, if the frequency range of concureently deployed services is known to be between approximately 90 kHz and approximately 200 kHz, but the fluctuations in power level are not known, then the adaptive filter may variably attenuate the PSD mask 752 within the fixed frequency range as a function of the line conditions. In an example embodiment, the variable attenuation may range from approximately 0 dB to approximately -12 dB. More specifically, in another embodiment, the variable attenuation may vary in a smaller range from approximately 0 dB to approximately -8 dB.
In yet another embodiment, the adaptive filter 754 is configured to provide a variable attenuation over a different fixed frequency range. In an example embodiment, the fixed frequency range is between approximately 4 kHz and approximately 26 kHz. The adaptive filter 754, in another embodiment, is configured to provide a variable attenuation over a variable frequency range. Thus, if neither the frequency range nor the fluctuations in power level due to other services is known with particularity, then the adaptive filter may variably attenuate the PSD mask 752 over a variable frequency range as a function of the line conditions. In an example embodiment, the variable frequency range may vary anywhere in the range of between approximately 90 kHz and approximately 200 kHz to accommodate services operating within that bandwidth. More specifically, in another embodiment, the variable frequency range may vary in a narrower frequency range of, for example, between approximately 121 kHz and approximately 164 kHz. The 164 kHz frequency is the location of the peak of the first lobe of the TCM ISDN bandwidth, and the 121 kHz frequency is the frequency at which downstream performance is optimized, upstream and downstream signals are balanced, and spectral compatibility between ADSL and concunently-deployed TCM ISDN services is optimized according to predefined conditions. The variable frequency range may also be between approximately 4 kHz and approximately 200 kHz, which is the range immediately above the POTS bandwidth and the upper operating frequencies of ISDN.
The processor 720 also comprises data loading logic 760, which loads each of the sub-carriers. In an example embodiment, once the line conditions have been determined and the optimum adaptively-filtered PSD mask has been generated or selected, the data loading logic 760 loads the sub-carriers with data according to the adaptively-filtered PSD mask. Thus, the data is loaded to each sub-carrier using an optimized power level as defined by the adaptively-filtered PSD mask.
Having described several embodiments of systems configured to generate adaptively-filtered PSD masks and load sub-carriers with data according to the adaptively-filtered PSD masks, attention is turned to FIGS. 8 through 24, which show several transfer functions of adaptive filters 754 and several embodiments of adaptively-filtered PSD masks.
FIG. 8 is a diagram showing one embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. Specifically, FIG. 8 shows a portion of the G.992.1 Annex A PSD mask having approximately -12 dB attenuation between approximately 92.5 kHz and approximately 122.5 kHz. Thus, rather than having a uniform peak power of approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 1104 kHz like the prior-art Annex A PSD mask of FIG. 1, the adaptively-filtered PSD mask of FIG. 8 has an approximately -12 dB attenuation "notch" between approximately 92.5 kHz and approximately 122.5 kHz. The "notch" reduces the power allocated to the frequency range defined by the "notch," thereby concomitantly reducing any cross-talk that the DSL service may induce into other services deployed on the communication line 555 within that frequency range.
FIG. 9A is a diagram showing a transfer function associated with one embodiment ofthe adaptive filter 754 of FIG. 7, which has a variable attenuation over a variable frequency range. In this regard, FIG. 9A shows a general adaptive filter 754 in which the attenuation bandwidth may be adaptively changed in response to detected line conditions. As shown in FIG. 9A, one embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a
frequency of f; attenuation between f\ and fi -A5 dBm Hz
Figure imgf000020_0001
attenuation between^ and/ ; and 0 dBm/Hz attenuation above f, where -A\, -A2, and - A , are attenuation values that are adaptively set in response to detected line conditions, and /ι, /2, and j are frequencies that are adaptively set in response to detected line conditions. FIG. 9B is a diagram showing a transfer function associated with one embodiment ofthe adaptive filter 754 of FIG. 7, which has a variable attenuation over a fixed frequency range. As shown in FIG. 9B, this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation
below a frequency of approximately 99 kHz; attenuation between
Figure imgf000020_0002
approximately 99 kHz and approximately 151 kHz; -As dBm/Hz attenuation between approximately 151 kHz and approximately 164 kHz; and 0 dBm Hz attenuation above approximately 164 kHz, where -A\, -A2, and -A5 are attenuation values that are adaptively set in response to detected line conditions.
FIG. 9C is a diagram showing a transfer function associated with one embodiment ofthe adaptive filter 754 of FIG. 7, which has a specific attenuation over a fixed frequency range. As shown in FIG. 9B, this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation
below a frequency of approximately 99 kHz; approximately -12
Figure imgf000021_0001
attenuation between approximately 99 kHz and approximately 151 kHz; approximately -32 dBm/Hz attenuation between approximately 151 kHz and approximately 164 kHz; and 0 dBm/Hz attenuation above approximately 164 kHz. For a fixed adaptive filter 754 similar to that shown in FIG. 9C, the processor 720 may selectively apply or not apply the notch filter to a PSD mask depending on the presence or absence of other services on the communication line 555, as indicated by the detected line conditions.
FIG. 10 is a diagram showing another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. As shown in FIG. 10, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below
approximately 4 kHz; approximately dBm/Hz between
Figure imgf000021_0002
approximately 4 kHz and approximately 26 kHz; approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 121 kHz; approximately
between approximately 121 kHz and approximately 151
Figure imgf000021_0003
kHz; approximately -74.5 dBm/Hz between approximately 151 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and
approximately 1104 kHz; approximately between
Figure imgf000022_0001
approximately 1104 kHz and approximately 3093 kHz; and approximately -90 dBm Hz above approximately 3093 kHz. Specifically, the PSD mask shown in FIG. 10 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility in Annex A and Annex C far-end cross-talk (FEXT) bit-mapped (FBM) systems. Since Annex A and Annex C are well known and, also, are described in the G.992.1 standard, further discussion of Annex A and Annex C is omitted here. FIG. 11 is a diagram showing yet another embodiment of an adaptively-filtered
PSD mask generated by the system of FIG. 7. As shown in FIG. 11, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below
approximately 4 kHz; approximately -97.5 + 17.8x /og2 I dBm/Hz between
approximately 4 kHz and approximately 26 kHz; approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 121 kHz; approximately
between approximately 121 kHz and approximately 151
Figure imgf000022_0002
kHz; approximately -86.5 dBm/Hz between approximately 151 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and
approximately 1104 kHz; approximately -36.5 - 36x between
Figure imgf000022_0003
approximately 1104 kHz and approximately 3093 kHz; and approximately -90 dBm Hz above approximately 3093 kHz. Specifically, the PSD mask shown in FIG. 11 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility in Annex A FBM systems.
FIG. 12 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation immediately above the plain old telephone system (POTS) bandwidth. As shown in FIG. 12, the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a
variable attenuation of - 97.5 + 4, between approximately 4 kHz and
Figure imgf000023_0001
approximately 26 kHz, where A4 is adaptively set in response to detected line conditions; approximately -36.5 dBm/Hz between approximately 26 kHz and
approximately 121 kHz; approximately between
Figure imgf000023_0002
approximately 121 kHz and approximately 151 kHz; approximately -86.5 dBm/Hz between approximately 151 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and approximately 1104 kHz; approximately
between approximately 1104 kHz and approximately 3093
Figure imgf000023_0003
kHz; and approximately -90 dBm/Hz above approximately 3093 kHz.
FIG. 13 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask having a variable attenuation between approximately 121 kHz and 164 kHz. As shown in FIG. 13, the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately
-97.5 + 17.8χ/og- |7Y) dBm Hz between approximately 4 kHz and approximately JJ 26 kHz; approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 121 kHz; a variable attenuation of approximately •49.5 - 4, between approximately 121 kHz and approximately 151
Figure imgf000024_0001
kHz; a variable attenuation of -Aβ dBm/Hz between approximately 151 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz
and approximately 1104 kHz; approximately -36.5 between
Figure imgf000024_0002
approximately 1104 kHz and approximately 3093 kHz; and approximately -90 dBm/Hz above approximately 3093 kHz, where - 2 and -Aβ are adaptively set in response to detected line conditions.
FIG. 14 is a diagram showing one embodiment of an adaptively-filtered PSD mask having a variable attenuation over a plurality of different frequency ranges. As shown in FIG. 14, the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a variable attenuation of
between approximately 4 kHz and approximately 26 kHz;
Figure imgf000024_0003
approximately -36.5 dBm Hz between approximately 26 kHz and approximately 121
kHz; a variable attenuation of approximately - 49.5 - A2
Figure imgf000024_0004
between llljj
approximately 121 kHz and approximately 151 kHz; a variable attenuation of -Aβ dBm/Hz between approximately 151 kHz and approximately 164 kHz; approximately - 36.5 dBm Hz between approximately 164 kHz and approximately 1104 kHz;
approximately 36.5 between approximately 1104 kHz and
Figure imgf000024_0005
approximately 3093 kHz; and approximately -90 dBm/Hz above approximately 3093 kHz, where -A2, -A4, and -Aβ are adaptively set in response to detected line conditions. FIG. 15 A is a diagram showing a transfer function associated with another embodiment ofthe adaptive filter 754 of FIG. 7, which has a variable attenuation over a variable frequency range. In this regard, FIG. 15A shows a general adaptive filter 754 in which the attenuation bandwidth may be adaptively changed in response to detected line conditions. As shown in FIG. 15A, one embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a frequency of/i; -43 dBm/Hz attenuation between f and/5; and 0 dBm/Hz attenuation above ≤, where -_43 is an attenuation value that is adaptively set in response to detected line conditions, and fc and fs are frequencies that are adaptively set in response to detected line conditions.
FIG. 15B is a diagram showing a transfer function associated with another embodiment ofthe adaptive filter 754 of FIG. 7, which has a variable attenuation over a fixed frequency range. As shown in FIG. 15B, this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a frequency of approximately 100 kHz; -A3 dBm/Hz attenuation between approximately 100 kHz and approximately 200 kHz; and 0 dBm/Hz attenuation above approximately 200 kHz, where -A3 is an attenuation value that is adaptively set in response to detected line conditions.
FIG. 15C is a diagram showing a transfer function associated with another embodiment ofthe adaptive filter 754 of FIG. 7, which has a specific attenuation over a fixed frequency range. As shown in FIG. 15C, this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a frequency of approximately 100 kHz; approximately -8 dBm/Hz attenuation between approximately 100 kHz and approximately 200 kHz; and 0 dBm/Hz attenuation above approximately 200 kHz. FIG. 15D is a diagram showing a transfer function associated with another embodiment ofthe adaptive filter 754 of FIG. 7, which has a specific attenuation over a fixed frequency range. As shown in FIG. 15D, this embodiment of the adaptive filter 754 is configured as a piece-wise linear function defined by 0 dBm/Hz attenuation below a frequency of approximately 100 kHz; approximately -12 dBm/Hz attenuation between approximately 100 kHz and approximately 200 kHz; and 0 dBm/Hz attenuation above approximately 200 kHz.
FIG. 16 is a diagram showing yet another embodiment of an adaptively-filtered
PSD mask generated by the system of FIG. 7. As shown in FIG. 16, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below
approximately 4 kHz; a variable attenuation of between
Figure imgf000026_0001
approximately 4 kHz and approximately 26 kHz; approximately -36.5 dBm Hz between approximately 26 kHz and approximately 147 kHz; approximately -41.5 dBm/Hz between approximately 147 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and approximately 1104 kHz; approximately
- 36.5 -36x between approximately 1104 kHz and approximately 3093
Figure imgf000026_0002
kHz; and approximately -90 dBm/Hz above approximately 3093 kHz, where -Ai, -4 , and -Aβ are adaptively set in response to detected line conditions.
FIG. 17 is a diagram showing another embodiment of an adaptively-filtered PSD mask having a variable attenuation within a variable frequency range. As shown in FIG. 17, the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a variable attenuation of
between approximately 4 kHz and approximately 26 kHz;
Figure imgf000026_0003
approximately -36.5 dBm/Hz between approximately 26 kHz and f kHz; a variable
attenuation of approximately (-36.5 - 4) dBm/Hz between /i kHz and f5 kHz;
approximately -36.5 dBm Hz between f kHz and approximately 1104 kHz;
approximately — 36.5 - between approximately 1104 kHz and
Figure imgf000027_0001
approximately 3093 kHz; and approximately -90 dBm/Hz above approximately 3093 kHz, where -A , fa,, and/s are adaptively set in response to detected line conditions.
FIG. 18 is a diagram showing another embodiment of an adaptively-filtered
PSD mask having a variable attenuation immediately above the POTS bandwidth. As shown in FIG. 17, the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a variable attenuation of
between approximately 4 kHz and approximately 26 kHz;
Figure imgf000027_0002
approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 147 kHz; approximately -41.5 dBm Hz between approximately 147 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and
approximately 1104 kHz; approximately - 36.5 - 36 between
Figure imgf000027_0003
approximately 1104 kHz and approximately 3093 kHz; and approximately -90 dBm/Hz above approximately 3093 kHz, where -An, is adaptively set in response to detected line conditions.
FIG. 19 is a diagram showing another embodiment of an adaptively-filtered PSD mask having a variable attenuation in several non-adjacent bandwidths. As shown in FIG. 19, the adaptively-filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; a variable attenuation of 97.5 + 4 x ( between approximately 4 kHz and approximately 26 kHz;
approximately -36.5 dBm/Hz between approximately 26 kHz and i kHz; a variable
attenuation of approximately (-36.5 - 4) dBm/Hz between fi kHz and f$ kHz;
approximately -36.5 dBm/Hz between f$ kHz and approximately 1104 kHz;
approximately between approximately 1104 kHz and
Figure imgf000028_0001
approximately 3093 kHz; and approximately -90 dBm/Hz above approximately 3093 kHz, where -A3, -A^f, zn.ά.f5 are adaptively set in response to detected line conditions. FIG. 20 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. As shown in FIG. 20, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -94.5 dBm/Hz between approximately 4 kHz and
approximately 31 kHz; approximately 94.5 dBm/Hz between
Figure imgf000028_0002
approximately 31 kHz and approximately 104 kHz; approximately
dBm/Hz between approximately 104 kHz and
Figure imgf000028_0003
approximately 134 kHz; approximately dBm/Hz between
Figure imgf000028_0004
approximately 134 kHz and approximately 175 kHz; approximately -36.5 dBm/Hz between approximately 175 kHz and approximately 1104 kHz; approximately
— 36.5 - 36x og9 between approximately 1104 kHz and approximately 3093
Figure imgf000028_0005
kHz; and approximately -90.5 dBm/Hz above approximately 3093 kHz. Specifically, the PSD mask shown in FIG. 20 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a near-end cross-talk (NEXT) period in extended reach Annex C systems adapted for time-frequency division duplexing. Since Annex C systems are known in the art and, also, are described in G.992.1, further discussion of Annex C systems and their requirements is omitted here.
FIG. 21 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. As shown in FIG. 21, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -94.5 dBm/Hz between approximately 4 kHz and
approximately 24 kHz; approximately dBm/Hz between
Figure imgf000029_0001
approximately 24 kHz and approximately 43 kHz; approximately
- 64.5 + 18 dBm/Hz between approximately 43 kHz and approximately
Figure imgf000029_0002
74 kHz; approximately dBm/Hz between approximately
Figure imgf000029_0003
74 kHz and approximately 121 kHz; approximately
Figure imgf000029_0004
dBm/Hz between approximately 121 kHz and approximately 171 kHz; approximately - 36.5 dBm/Hz between approximately 171 kHz and approximately 1104 kHz;
approximately - 36.5 - 36 x between approximately 1104 kHz and
Figure imgf000029_0005
approximately 3093 kHz; and approximately -90.5 dBm/Hz above approximately 3093 kHz. Specifically, the PSD mask shown in FIG. 21 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a far-end cross-talk (FEXT) period in extended reach Annex C systems adapted for time-frequency division duplexing.'
FIG. 22 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. As shown in FIG. 22, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -86.5 dBm/Hz between approximately 4 kHz and
approximately 10 kHz; approximately 86.5 + 25.8x og2 dBm/Hz between
approximately 10 kHz and approximately 27 kHz; approximately
- 49.5 dBm/Hz between approximately 27 kHz and
Figure imgf000030_0001
approximately 70 kHz; approximately -36.5 dBm/Hz between approximately 70 kHz
and approximately 1104 kHz; approximately - 36.5 - 36 x between
Figure imgf000030_0002
approximately 1104 kHz and approximately 3093 kHz; and approximately -90.5 dBm/Hz above approximately 3093 kHz. Specifically, the PSD mask shown in FIG. 22 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a far-end cross-talk (FEXT) period in FEXT bit-mapped (FBM) Annex C systems.
FIG. 23 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. As shown in FIG. 23, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm Hz below
approximately 4 kHz; approximately -97.5 + l l x /og2 dBm/Hz between 4
approximately 4 kHz and approximately 50 kHz; approximately
- 57.5 dBm/Hz between approximately 50 kHz and approximately
Figure imgf000030_0003
126 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and
approximately 1104 kHz; approximately - 36.5 - 36 x between
Figure imgf000031_0001
approximately 1104 kHz and approximately 3093 kHz; and approximately -90.5 dBm/Hz above approximately 3093 kHz. Specifically, the PSD mask shown in FIG. 23 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a far-end cross-talk (FEXT) period in Annex C systems adapted for time-frequency division duplexing.
FIG. 24 is a diagram showing yet another embodiment of an adaptively-filtered PSD mask generated by the system of FIG. 7. As shown in FIG. 24, the adaptively- filtered PSD mask is defined by power levels of approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -94.5 dBm/Hz between approximately 4 kHz and
approximately 32 kHz; approximately - 94.5 + 20.65 x dBm Hz between
Figure imgf000031_0002
approximately 32 kHz and approximately 109 kHz; approximately
dBm/Hz between approximately 109 kHz and approximately
Figure imgf000031_0003
138 kHz; approximately 38.3 + 3.36x log. dBm/Hz between approximately
Figure imgf000031_0004
138 kHz and approximately 200 kHz; approximately -36.5 dBm/Hz between approximately 200 kHz and approximately 1104 kHz; approximately
between approximately 1104 kHz and approximately 3093
Figure imgf000031_0005
kHz; and approximately -90.5 dBm Hz above approximately 3093 kHz. Specifically, the PSD mask shown in FIG. 24 is configured to optimize downstream performance, balance downstream and upstream signal ratios, and provide spectral compatibility during a near-end cross-talk (NEXT) period in Annex C systems adapted for time- frequency division duplexing.
FIG. 25 is a flowchart showing one embodiment of a method employing adaptively-filtered PSD masks. As shown in FIG. 25, one embodiment of the method begins when a DMT-modulated communication system receives (2520) a signal from a communication line 555. The received (2520) signal has information indicative of services deployed on the communication line 555. In this regard, the received (2520) signal contains information related to line conditions. Upon receiving (2520) the signal, the DMT-modulated communications system adaptively determines (2530) a power level of a DMT sub-carrier. Additionally, the DMT-modulated communication system adaptively attenuates (2540) power within a portion of a PSD mask using the adaptively determined (2530) power level of the DMT sub-carrier. Thereafter, the DMT sub-carrier is loaded (2550) with data according to the adaptively determined (2530) power level. In an example embodiment, the method of FIG. 25 may be performed by the systems described with reference to FIGS. 5 through 24. However, it should be understood that other communication systems employing DMT modulation might also perform the steps described with reference to FIG. 25.
The service determination logic 730, the power determination logic 740, the power allocation logic 750, and the data loading logic 760 ofthe present invention can be implemented in hardware, software, firmware, or a combination thereof. In the ' prefened embodiment(s), the service determination logic 730, the power determination logic 740, the power allocation logic 750, and the data loading logic 760 is implemented in hardware using any or a combination of the following technologies, which are all well known in the art: a discrete logic circuit(s) having logic gates for implementing logic functions upon data signals, an application specific integrated circuit (ASIC) having appropriate combinational logic gates, a programmable gate array(s) (PGA), a field programmable gate anay (FPGA), etc. In an alternative embodiment, the service determination logic 730, the power determination logic 740, the power allocation logic 750, and the data loading logic 760 is implemented in software or firmware that is stored in a memory and that is executed by a suitable instruction execution system.
Any process descriptions or blocks in flow charts should be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
Although an exemplary embodiment of the present invention has been shown and described, it will be apparent to those of ordinary skill in the art that a number of changes, modifications, or alterations to the invention as described may be made, none of which depart from the spirit of the present invention. For example, while the processor and logic configured to adaptively calculate the DMT sub-carrier power level are shown within the encoding and gain scaling block, it should be appreciated that the processor and logic configured to adaptively calculate the DMT sub-carrier power level may also be located as a separate unit outside of the encoding and gain scaling block. Also, while exemplary embodiments ofthe present invention have been described with reference to a digital subscriber line (DSL) system, it should be understood that the systems and methods presented herein may be implemented in other digital communication systems that employ sub-carriers for data transmission. Additionally, while specific examples of PSD masks have been shown with reference to FIGS. 8, 10- 14, and 16-24, it should be appreciated that the various cutoff frequencies and attenuation values shown as fixed values may be adjusted to maximize downstream performance, balance upstream and downstream signals, and provide greater spectral compatibility with concurrently deployed services, such as ISDN services. All such changes, modifications, and alterations should therefore be seen as within the scope of the present invention.

Claims

The claims are:
1. A discrete multi-tone (DMT) modulated communication system comprising: a receiver configured to receive signals from a communication line, the signals having information indicative of line conditions; and logic configured to adaptively calculate a power level of a DMT sub-carrier in response to received signals from the communication line.
2. The system of claim 1, wherein the logic configured to adaptively calculate the power level of the DMT sub-carrier comprises logic configured to determine a signal-to-noise ratio (SNR) ofthe communication line.
3. The system of claim 1, wherein the logic configured to adaptively calculate the power level of the DMT sub-carrier comprises logic configured to determine line attenuation information ofthe communication line.
4. The system of claim 1, wherein the logic configured to adaptively calculate the power level of the DMT sub-carrier comprises logic configured to determine information related to usable sub-carriers in the DMT modulated system.
5. The system of claim 1, further comprising logic configured to load the DMT sub-carrier with data, the DMT sub-carrier being loaded as a function of the adaptively-determined power level.
6. A discrete multi-tone (DMT) modulated digital subscriber line (DSL) system comprising: an adaptively-filtered power spectral density (PSD) mask having an attenuated portion, the attenuated portion configured to adaptively change in response to line characteristics; and logic configured to load DMT sub-camers with data, the DMT sub-carriers being loaded according to the adaptively-filtered PSD mask.
7. The system of claim 6, further comprising: a receiver configured to receive signals from a communication line, the signals having information indicative line conditions; and logic configured to adaptively determine the services deployed on the communication line from the received signals.
8. The system of claim 7, wherein the attenuated portion is further configured to change in response to the adaptively determined services deployed on the communication line.
9. The system of claim 6, wherein the attenuated portion has a variable power over a fixed frequency range.
10. The system of claim 6, wherein the attenuated portion has a variable power over a variable frequency range.
11. A system comprising: an adaptive filter having an attenuation bandwidth, the adaptive filter configured to adaptively attenuate power within a portion of a power spectral density (PSD) mask to generate an adaptively-filtered PSD mask; and logic configured to allocate power to sub-carriers in a discrete multi-tone (DMT) modulated communication system, the power being allocated according to the adaptively-filtered PSD mask.
12. The system of claim 11, wherein the adaptive filter is configured to selectively provide a fixed attenuation over a fixed frequency range.
13. The system of claim 12, wherein the fixed attenuation over the fixed frequency range is approximately -8 dB between approximately 100 kHz and approximately 200 kHz.
14. The system of claim 12, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz;
approximately -97.5 + 17.8 xlog2 L dBm/Hz between approximately 4
kHz and approximately 26 kHz; approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 147 kHz; approximately -41.5 dBm/Hz between approximately 147 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and approximately 1104 kHz;
approximately -36.5 - 36 between approximately 1104 kHz
Figure imgf000038_0001
and approximately 3093 kHz; and approximately -90 dBm/Hz above approximately 3093 kHz.
15. The system of claim 12, wherein the fixed attenuation over the fixed frequency range is:
approximately between approximately 99 kHz and
Figure imgf000038_0002
approximately 151 kHz; and approximately -32 dBm/Hz between approximately 151 kHz and approximately 164 kHz.
16. The system of claim 12, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz;
approximately dBm/Hz between approximately 4
Figure imgf000039_0001
kHz and approximately 26 kHz; approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 121 kHz;
approximately - 49.5 dBm/Hz between approximately
Figure imgf000039_0002
121 kHz and approximately 151 kHz; approximately -86.5 dBm/Hz between approximately 151 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and approximately 1104 kHz;
approximately 36.5 between approximately 1104 kHz
Figure imgf000039_0003
and approximately 3093 kHz; and approximately -90 dBm/Hz above approximately 3093 kHz.
17. The system of claim 12, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm Hz below approximately 4 kHz;
approximately -97.5 + 17.8 xlog. ( ) dBm/Hz between approximately 4 JJ kHz and approximately 26 kHz; approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 121 kHz;
approximately 49.5 - dBm/Hz between approximately
Figure imgf000040_0001
121 kHz and approximately 151 kHz; approximately -74.5 dBm/Hz between approximately 151 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and approximately 1104 kHz;
approximately - 36.5 between approximately 1104 kHz
Figure imgf000040_0002
and approximately 3093 kHz; and approximately -90 dBm/Hz above approximately 3093 kHz.
18. The system of claim 12, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -94.5 dBm/Hz between approximately 4 kHz and approximately 31 kHz;
dBm Hz between approximately 31
Figure imgf000041_0001
kHz and approximately 104 kHz;
approximately dBm/Hz between approximately
Figure imgf000041_0002
104 kHz and approximately 134 kHz;
approximately dBm Hz between approximately 134
Figure imgf000041_0003
kHz and approximately 175 kHz; approximately -36.5 dBm/Hz between approximately 175 kHz and approximately 1104 kHz;
approximately - between approximately 1104 kHz
Figure imgf000041_0004
and approximately 3093 kHz; and approximately -90.5 dBm Hz above approximately 3093 kHz.
19. The system of claim 12, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -94.5 dBm/Hz between approximately 4 kHz and approximately 24 kHz;
approximately - 80 dBm/Hz between approximately 24
Figure imgf000042_0001
kHz and approximately 43 kHz;
approximately dBm/Hz between approximately 43
Figure imgf000042_0002
kHz and approximately 74 kHz;
dBm/Hz between approximately 74
Figure imgf000042_0003
kHz and approximately 121 kHz;
approximately - dBm/Hz between approximately
Figure imgf000042_0004
121 kHz and approximately 171 kHz; approximately -36.5 dBm/Hz between approximately 171 kHz and approximately 1104 kHz;
approximately - 36.5 - 36 x log2 f W between approximately 1104 kHz y 1n10υ4^
and approximately 3093 kHz; and approximately -90.5 dBm/Hz above approximately 3093 kHz.
20. The system of claim 12, wherem the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -86.5 dBm/Hz between approximately 4 kHz and approximately 10 kHz;
approximately dBm/Hz between approximately 10
Figure imgf000043_0001
kHz and approximately 27 kHz;
approximately 49.5 + 9.46x dBm/Hz between approximately 27
Figure imgf000043_0002
kHz and approximately 70 kHz; approximately -36.5 dBm/Hz between approximately 70 kHz and approximately 1104 kHz;
approximately - 36.5 between approximately 1104 kHz
Figure imgf000043_0003
and approximately 3093 kHz; and approximately -90.5 dBm/Hz above approximately 3093 kHz.
21. The system of claim 12, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz;
approximately - 97.5 + l lx /og2 |7Y| JJ dBm/Hz between approximately 4 kHz
and approximately 50 kHz;
approximately - 57.5 + 15.7 x dBm/Hz between approximately 50
Figure imgf000044_0001
kHz and approximately 126 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and approximately 1104 kHz;
approximately between approximately 1104 kHz
Figure imgf000044_0002
and approximately 3093 kHz; and approximately -90.5 dBm/Hz above approximately 3093 kHz.
22. The system of claim 12, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz; approximately -94.5 dBm/Hz between approximately 4 kHz and approximately 32 kHz;
approximately dBm/Hz between approximately 32
Figure imgf000045_0001
kHz and approximately 109 kHz;
approximately - 58 + 58 x dBm/Hz between approximately 109
Figure imgf000045_0002
kHz and approximately 138 kHz;
approximately 38.3 + dBm/Hz between approximately
Figure imgf000045_0003
138 kHz and approximately 200 kHz; approximately -36.5 dBm/Hz between approximately 200 kHz and approximately 1104 kHz;
approximately between approximately 1104 kHz
Figure imgf000045_0004
and approximately 3093 kHz; and approximately -90.5 dBm/Hz above approximately 3093 kHz.
23. The system of claim 11, wherein the adaptive filter is configured to provide a variable attenuation over a fixed frequency range.
24. The system of claim 23, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz;
approximately dBm/Hz between approximately 4
Figure imgf000046_0001
kHz and approximately 26 kHz; approximately -36.5 dBm Hz between approximately 26 kHz and approximately 147 kHz; an adaptively varying power level between approximately 147 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and approximately 1104 kHz;
approximately between approximately 1104 kHz
Figure imgf000046_0002
and approximately 3093 kHz; and approximately -90 dBm/Hz above approximately 3093 kHz.
25. The system of claim 23, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz; an adaptively varying power level between approximately 4 kHz and approximately 26 kHz; approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 147 kHz; approximately -41.5 dBm/Hz between approximately 147 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and approximately 1104 kHz;
approximately between approximately 1104 kHz
Figure imgf000047_0001
and approximately 3093 kHz; and approximately -90 dBm Hz above approximately 3093 kHz.
26. The system of claim 23, wherein the adaptively-filtered PSD mask is defined by power levels of: approximately -97.5 dBm/Hz below approximately 4 kHz; an adaptively varying power level between approximately 4 kHz and approximately 26 kHz; approximately -36.5 dBm/Hz between approximately 26 kHz and approximately 147 kHz; an adaptively varying power level between approximately 147 kHz and approximately 164 kHz; approximately -36.5 dBm/Hz between approximately 164 kHz and approximately 1104 kHz;
approximately - 36.5 - 36x between approximately 1104 kHz
Figure imgf000048_0001
and approximately 3093 kHz; and approximately -90 dBm Hz above approximately 3093 kHz.
27. The system of claim 24, wherein the adaptively varying power level ranges from approximately 0 dBm/Hz to approximately -12 dBm/Hz.
28. The system of claim 11, wherein the adaptive filter is configured to provide a fixed attenuation over a variable frequency range.
29. The system of claim 28, wherein the fixed attenuation is approximately - 8 dBm/Hz.
30. The system of claim 28, wherein the fixed attenuation is approximately - 12 dBm/Hz.
31. The system of claim 11, wherein the adaptive filter is configured to provide a variable attenuation over a variable frequency range.
32. In a discrete multi-tone (DMT) modulated communication system, a method comprising: receiving a signal from a communication line, the signal having information indicative of line conditions; and adaptively determining a power level of a DMT sub-canier in response to receiving the signal from the communication line.
33. The method of claim 32, further comprising: loading the DMT sub-carrier with data, the DMT sub-carrier being loaded according to the adaptively determined power level.
34. The method of claim 32, further comprising: adaptively attenuating power within a portion of a power spectral density (PSD) mask.
35. The method of claim 34, wherein the adaptively attenuating power within the portion ofthe PSD mask comprises: variably attenuating a fixed bandwidth.
36. The method of claim 35, wherein the variably attenuating a fixed bandwidth comprises: variably attenuating DMT sub-carriers between approximately 100 kHz and approximately 200 kHz
37. The method of claim 35, wherein the variably attenuating a fixed bandwidth comprises: variably attenuating DMT sub-carriers between approximately 4 kHz and approximately 26 kHz
38. The method of claim 35, wherein the variably attenuating a fixed bandwidth comprises: variably attenuating DMT sub-carriers between approximately 121 kHz and approximately 164 kHz
39. The method of claim 34, wherein the adaptively attenuating power within the portion ofthe PSD mask comprises: variably attenuating a variable bandwidth.
40. In a discrete multi-tone (DMT) modulated communication system, a system comprising: means for receiving a signal from a communication line, the signal having information indicative of line conditions; and means for adaptively determining a power level of a DMT sub-carrier in response to receiving the signal from the communication line.
41. The system of claim 40, further comprising: means for loading the DMT sub-carrier with data, the DMT sub-canier being loaded according to the adaptively determined power level.
42. The system of claim 40, further comprising: means for adaptively attenuating power within a portion of a power spectral density (PSD) mask.
PCT/US2002/039460 2001-12-10 2002-12-10 System and method for reducing noise induced by digital subscriber line (dsl) systems into services that are concurrently deployed on a communication line WO2003055162A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002357134A AU2002357134A1 (en) 2001-12-10 2002-12-10 System and method for reducing noise induced by digital subscriber line (dsl) systems into services that are concurrently deployed on a communication line

Applications Claiming Priority (16)

Application Number Priority Date Filing Date Title
US33893901P 2001-12-10 2001-12-10
US60/338,939 2001-12-10
US60/341,654 2001-12-16
US34165401P 2001-12-17 2001-12-17
US34680902P 2002-01-07 2002-01-07
US60/346,809 2002-01-07
US34857502P 2002-01-14 2002-01-14
US60/348,575 2002-01-14
US35055202P 2002-01-22 2002-01-22
US60/350,552 2002-01-22
US35388002P 2002-02-02 2002-02-02
US60/353,880 2002-02-02
US35488802P 2002-02-06 2002-02-06
US60/354,888 2002-02-06
US35511702P 2002-02-08 2002-02-08
US60/355,117 2002-02-08

Publications (1)

Publication Number Publication Date
WO2003055162A1 true WO2003055162A1 (en) 2003-07-03

Family

ID=27575406

Family Applications (3)

Application Number Title Priority Date Filing Date
PCT/US2002/039446 WO2003050653A2 (en) 2001-12-10 2002-12-10 System and method for increasing data capacity in communication systems
PCT/US2002/039406 WO2003050991A2 (en) 2001-12-10 2002-12-10 System and method for improving data transmission
PCT/US2002/039460 WO2003055162A1 (en) 2001-12-10 2002-12-10 System and method for reducing noise induced by digital subscriber line (dsl) systems into services that are concurrently deployed on a communication line

Family Applications Before (2)

Application Number Title Priority Date Filing Date
PCT/US2002/039446 WO2003050653A2 (en) 2001-12-10 2002-12-10 System and method for increasing data capacity in communication systems
PCT/US2002/039406 WO2003050991A2 (en) 2001-12-10 2002-12-10 System and method for improving data transmission

Country Status (3)

Country Link
US (3) US6829251B2 (en)
AU (3) AU2002357134A1 (en)
WO (3) WO2003050653A2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1702417A1 (en) * 2004-01-09 2006-09-20 Conexant System, Inc. Real-time formation of optimal power spectral density masks

Families Citing this family (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7260067B2 (en) * 2001-05-22 2007-08-21 Agere Systems Inc. Spectrum and bin reassignment protocol for ADSL
US7126984B2 (en) * 2001-12-19 2006-10-24 Stmicroelectronics, Inc. Near-end crosstalk noise minimization and power reduction for digital subscriber loops
US7103004B2 (en) * 2001-12-19 2006-09-05 Stmicroelectronics, Inc. Method and apparatus for application driven adaptive duplexing of digital subscriber loops
US7372899B2 (en) * 2002-07-25 2008-05-13 Brooktree Broadband Holding, Inc. Reduced symbol rate handshake signaling in ADSL systems
US7103729B2 (en) * 2002-12-26 2006-09-05 Intel Corporation Method and apparatus of memory management
US7818252B2 (en) * 2003-02-20 2010-10-19 Gilat Satellite Networks, Ltd Enforcement of network service level agreements
IL156018A0 (en) * 2003-05-20 2003-12-23 Surf Comm Solutions Ltd Long range broadband modem
JP2005057449A (en) * 2003-08-01 2005-03-03 Matsushita Electric Ind Co Ltd Adsl modem apparatus and communication method thereof
US7386039B2 (en) * 2003-09-26 2008-06-10 Tollgrade Communications, Inc. Method and apparatus for identifying faults in a broadband network
US7564932B2 (en) * 2003-11-26 2009-07-21 Conexant Systems, Inc. Method and system for enhancing bit rate in DMT quad spectrum systems
CA2457969A1 (en) * 2004-01-14 2005-07-14 Yaron Mayer System and method for improving the balance between download and upload traffic on the internet and/or other networks
IL160665A (en) * 2004-03-01 2010-11-30 Eci Telecom Ltd Method and device for providing communication services
EP1653721A1 (en) * 2004-11-02 2006-05-03 Alcatel Modem with selectable power spectral density masks
US7991122B2 (en) 2005-06-02 2011-08-02 Adaptive Spectrum And Signal Alignment, Inc. DSL system training
US8824453B2 (en) * 2006-04-14 2014-09-02 At&T Intellectual Property I, Lp Method and apparatus for managing quality of service for multimedia applications
US20140369480A1 (en) 2013-06-12 2014-12-18 Adaptive Spectrum And Signal Alignment, Inc. Systems, methods, and apparatuses for implementing a dsl system
EP2030454B2 (en) * 2006-06-06 2016-09-07 Adaptive Spectrum and Signal Alignment, Inc. Vectored dsl system
KR100945827B1 (en) * 2008-04-08 2010-03-05 주식회사 휴커넥스 Point-to-multipoint network device using phone-line
CN102379090B (en) * 2009-03-04 2015-01-21 适应性频谱和信号校正股份有限公司 Dsl noise cancellation
US9197289B2 (en) * 2010-11-24 2015-11-24 Mediatek Inc. Dynamic transmit power control method and power line communication system
US9374166B2 (en) * 2012-02-13 2016-06-21 Ciena Corporation High speed optical communication systems and methods with flexible bandwidth adaptation
US10257596B2 (en) 2012-02-13 2019-04-09 Ciena Corporation Systems and methods for managing excess optical capacity and margin in optical networks
WO2015038141A1 (en) * 2013-09-13 2015-03-19 Hewlett-Packard Development Company, L.P. Subcarrier power reallocation
US9332046B2 (en) * 2013-10-17 2016-05-03 Cisco Technology, Inc. Rate-adapted delivery of virtual desktop image elements by an edge server in a computer network environment
US9362959B2 (en) * 2014-05-05 2016-06-07 Adtran Inc. Data processing in a digital subscriber line environment
AU2015295710B2 (en) * 2014-07-30 2017-02-02 British Telecommunications Public Limited Company Method and apparatus for allocating power levels to a transmission in a digital subscriber line network
US10367546B2 (en) 2015-04-09 2019-07-30 Sckipio Technologies S.I Ltd Communication method and system adapted for concurrently operating over a communication channel susceptible to crosstalk from at least a second communication system
US9831947B2 (en) 2016-04-20 2017-11-28 Ciena Corporation Margin determination systems and methods in optical networks
US10680843B2 (en) 2016-12-21 2020-06-09 British Telecommunications Public Limited Company Network node
US10587339B1 (en) * 2018-11-27 2020-03-10 Ciena Corporation Systems and methods for achieving best effort home route capacity on protection paths during optical restoration

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5742527A (en) * 1996-03-15 1998-04-21 Motorola, Inc. Flexible asymmetrical digital subscriber line (ADSL) receiver, central office using same, and method therefor
US6219378B1 (en) * 1997-09-17 2001-04-17 Texas Instruments Incorporated Digital subscriber line modem initialization
US6285708B1 (en) * 1997-12-31 2001-09-04 At&T Corp. Spread spectrum bit allocation algorithm
US20010022777A1 (en) * 1999-12-03 2001-09-20 Catena Networks, Inc. Peak to average power ratio reduction in communication systems
US20020075952A1 (en) * 2000-04-04 2002-06-20 Tioga Technologies, Inc. Communication start-up with variant spectral density mask

Family Cites Families (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2065344A (en) * 1933-02-01 1936-12-22 Gen Electric Control means for signal control transmission systems
US5479447A (en) * 1993-05-03 1995-12-26 The Board Of Trustees Of The Leland Stanford, Junior University Method and apparatus for adaptive, variable bandwidth, high-speed data transmission of a multicarrier signal over digital subscriber lines
US5519731A (en) * 1994-04-14 1996-05-21 Amati Communications Corporation ADSL compatible discrete multi-tone apparatus for mitigation of T1 noise
JP2899533B2 (en) * 1994-12-02 1999-06-02 株式会社エイ・ティ・アール人間情報通信研究所 Sound quality improvement device
US5495483A (en) * 1995-01-26 1996-02-27 Motorola, Inc. Method and apparatus for allocating carrier channels
US5852567A (en) * 1996-07-31 1998-12-22 Hughes Electronics Corporation Iterative time-frequency domain transform method for filtering time-varying, nonstationary wide band signals in noise
US6061392A (en) 1996-12-17 2000-05-09 Paradyne Corporation Apparatus and method for communicating voice and data between a customer premises and a central office
US6400759B1 (en) * 1997-06-30 2002-06-04 Integrated Telecom Express, Inc. Device driver for rate adaptable modem with forward compatible and expandable functionality
US5982784A (en) 1997-07-07 1999-11-09 Advanced Micro Devices Bandwidth sharing for remote and local data transfers using multicarrier modulation over common transmission medium
US6292559B1 (en) 1997-12-19 2001-09-18 Rice University Spectral optimization and joint signaling techniques with upstream/downstream separation for communication in the presence of crosstalk
US6259746B1 (en) * 1998-01-14 2001-07-10 Motorola Inc. Method for allocating data and power in a discrete multi-tone communication system
JP3082756B2 (en) * 1998-02-27 2000-08-28 日本電気株式会社 Multi-carrier transmission system and method
US6061932A (en) * 1998-04-29 2000-05-16 Coflexip Stena Offshore Steerable underwater plow with movable body member
JP3152217B2 (en) * 1998-10-09 2001-04-03 日本電気株式会社 Wire transmission device and wire transmission method
US6452907B1 (en) 1998-10-15 2002-09-17 Motorola, Inc. Method for monitoring unused bins in a discrete multi-toned communication system
US6693957B1 (en) * 1998-12-31 2004-02-17 Nortel Networks Limited Adaptive front end for discrete multitone modem
US6973122B1 (en) * 2001-01-26 2005-12-06 At&T Corp. Power allocation scheme for DMT-based modems employing simplex transmission

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5742527A (en) * 1996-03-15 1998-04-21 Motorola, Inc. Flexible asymmetrical digital subscriber line (ADSL) receiver, central office using same, and method therefor
US6219378B1 (en) * 1997-09-17 2001-04-17 Texas Instruments Incorporated Digital subscriber line modem initialization
US6285708B1 (en) * 1997-12-31 2001-09-04 At&T Corp. Spread spectrum bit allocation algorithm
US20010022777A1 (en) * 1999-12-03 2001-09-20 Catena Networks, Inc. Peak to average power ratio reduction in communication systems
US20020075952A1 (en) * 2000-04-04 2002-06-20 Tioga Technologies, Inc. Communication start-up with variant spectral density mask

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1702417A1 (en) * 2004-01-09 2006-09-20 Conexant System, Inc. Real-time formation of optimal power spectral density masks
EP1702417A4 (en) * 2004-01-09 2012-09-05 Ikanos Technology Ltd Real-time formation of optimal power spectral density masks

Also Published As

Publication number Publication date
WO2003050991A3 (en) 2003-09-25
AU2002357124A1 (en) 2003-06-23
AU2002357124A8 (en) 2003-06-23
US20030108065A1 (en) 2003-06-12
US20030108095A1 (en) 2003-06-12
WO2003050653A2 (en) 2003-06-19
US6829251B2 (en) 2004-12-07
AU2002357134A1 (en) 2003-07-09
WO2003050653A3 (en) 2004-02-26
AU2002360541A1 (en) 2003-06-23
WO2003050991A2 (en) 2003-06-19
US20030108035A1 (en) 2003-06-12
AU2002360541A8 (en) 2003-06-23

Similar Documents

Publication Publication Date Title
US20030108095A1 (en) System and method for reducing noise induced by digital subscriber line (DSL) systems into services that are concurrently deployed on a communication line
US6128349A (en) Method and apparatus for superframe bit allocation
US8934555B2 (en) Method and multi-carrier transceiver with stored application profiles for supporting multiple applications
EP0934638B1 (en) Method and apparatus for superframe bit allocation in a discrete multitone (dmt) system
US7813434B2 (en) Systems and methods for improved bit loading for discrete multi-tone modulated multiple latency applications
US7907658B2 (en) Systems and methods for resolving signal-to-noise ratio margin difference in dual latency discrete multi-tone-based xDSL systems under colored noise conditions
US20060062288A1 (en) Short loop ADSL power spectral density management
JPH11313044A (en) Method and device for providing user data speed over wide range inside multicarrier data communication system
US11411603B2 (en) Device for transmitting and receiving on a copper wire installed at a customer premise
JPH11308357A (en) Data communication device
JP2003517775A (en) Bit allocation method in multicarrier system
CA2382522C (en) Multicarrier system with dynamic switching between active application sets
US20040240464A1 (en) Method of transmitting data to reduce bit errors in communication systems
US6741604B1 (en) ADSL transmission in the presence of low-frequency network services
EP1437871A1 (en) System and method for reducing disruption in a DSL environment caused by a POTS transient event
EP2146473B1 (en) Method and device for data processing and communication system comprising such device
KR100926196B1 (en) Multicarrier system with stored application profiles for supporting multiple applications
US20030179622A1 (en) Dual modulation tuning in systems that exhibit self-disturbance effects
WO2003073624A2 (en) Dual modulation tuning in systems that exhibit self-disturbance effects

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SK SL TJ TM TN TR TT TZ UA UG UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LU MC NL PT SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP