CN100477778C - Wireless transmission system and method for channel switching - Google Patents

Wireless transmission system and method for channel switching Download PDF

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Publication number
CN100477778C
CN100477778C CNB2005100923239A CN200510092323A CN100477778C CN 100477778 C CN100477778 C CN 100477778C CN B2005100923239 A CNB2005100923239 A CN B2005100923239A CN 200510092323 A CN200510092323 A CN 200510092323A CN 100477778 C CN100477778 C CN 100477778C
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China
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frequency
channel
operating frequency
transmitting terminal
receiving terminal
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Expired - Fee Related
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CNB2005100923239A
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Chinese (zh)
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CN1921604A (en
Inventor
赖威廷
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BenQ Corp
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BenQ Corp
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Abstract

The invention relates to a wireless transmitter, which comprises: sender for selectively using the first program and second program to transmit data; the central frequency of first program is original frequency; the central frequency of second program is target frequency; and a receiver. Wherein, when the receiver receives data from the first program, the sender and the receiver are work at the first and second working frequencies, while the first and second working frequencies are original frequency; when the sender switches from the first to the second program, the sender adds one bias frequency at the first working frequency, and adjusts the second working frequency to be same as the first working frequency, and the sender repeatedly adds bias frequency, until the first and second working frequencies both are target frequency.

Description

The method that wireless transmitting system and channel switch
Technical field
The present invention refers in particular to a kind of wireless audio-video transmission system about a kind of transmission system.
Background technology
Radio area network (Wireless Local Area Network is hereinafter to be referred as WLAN) is played an important role in following family life.This technology of WLAN makes the user can appreciate the transmission of content of multimedia, data or information in any position of family easily and quickly.As long as the place that the radio wave energy arrives, the consumer need not painstakingly draw a transmission lines, therefore can appreciate film without restriction, browses world-wide web on rest limit, limit, courtyard, perhaps works in the garage and watches sports tournament etc. in passing.
After wireless transmitting system has been installed, any content display apparatus (wireless transceiver has been installed), as the TV in the bedroom, all should be able to be from family any video/audio source access content in other place, as: be placed on the parlor personal video recorder of wireless transceiver or the personal computer that the room has wireless transmission function be installed.Generally speaking, wireless audiovisual appliances comprises a display end (it can be considered as client), a remote controller and a signal source end (it can be considered as access point), and wherein display end and signal source end all have the function of wireless receiving and dispatching.
When the user when watching image, if when feeling to make that because of noise jamming picture quality is not good, exporting a channel with remote controller instructs to the signal source end, to require the communication channel between display end and the signal source end to switch to another communication channel, to avoid noise jamming, for example: 1. be example with 802.11b, switch to another idle channels 2.462GHz from original channel 2.412GHz.2. be example with 802.11a, switch to another idle channels 5280GHz from original channel 5200GHz.
And in wireless phonotape and videotape transmission, according to existing 802.11 standards, if will switch wireless communication channel, after signal source end and display end need broken string (disassociate), again connect, this program will spend the several seconds and cause image to pause, and the user is not felt well again.
Therefore the present invention will provide the method for a kind of wireless audio-video transmission system and channel seamless switching, make the user when switching channels, no longer include the situation generation that image pauses.
Summary of the invention
The object of the present invention is to provide a kind of wireless transmitting system, make system when channel switches, do not have the situation generation that image pauses.
The method that the object of the present invention is to provide a kind of wireless transmission channel to switch is utilized and is repeated to increase deviation frequency, switches and reach the unbroken channel of transfer of data.
The present invention discloses a kind of wireless transmitting system, this system comprises at least: a transmitting terminal (AccessPoint), optionally use one first adjacent channel and one second channel to transmit data, wherein, the centre frequency of first channel is a primary frequency, and the centre frequency of second channel is a purpose frequency; And a receiving terminal (Client), receive data from first channel.Transmitting terminal and receiving terminal operate on one first operating frequency and one second operating frequency respectively, when receiving terminal when transmitting terminal receives data via first channel, first operating frequency equates with second operating frequency and is set at primary frequency, when transmitting terminal when first channel switches to second channel, this transmitting terminal increases by skew (off-set) frequency in this first operating frequency, and it is consistent with first operating frequency to regulate second operating frequency, transmitting terminal is by repeating to increase deviation frequency, equal the purpose frequency up to first and second operating frequency, and it is very little owing to deviation frequency in the process of transmitting terminal increase deviation frequency with respect to operating frequency, therefore receiving terminal still can be received the data that transmitting terminal sends after transmitting terminal increases deviation frequency, so transfer of data can't be interrupted in channel changeover program of the present invention.
The present invention proposes a kind of channel switching method of wireless transmitting system in addition: the user sends a channel switching instruction; Transmitting terminal receives instruction, and transmits a user profile and reach an agreement on to receiving terminal, so that first operating frequency switches to the purpose frequency; First operating frequency of transmitting terminal increases by skew (off-set) frequency, and notifies receiving terminal with the first operating frequency position with a supervisory packet; Receiving terminal receiving management bag is regulated second operating frequency, makes it identical with first operating frequency; The information that receiving terminal is finished adjusting is back to transmitting terminal with a packet; Transmitting terminal receives packet, and compares present place first operating frequency and whether equal the purpose frequency; Transmitting terminal place first operating frequency repeats above-mentioned steps and equals the purpose frequency until first and second operating frequency if be not equal to the purpose frequency, and the channel that promptly finishes wireless transmitting system switches.
The present invention utilizes the scope of covering frequence can influence the signal transmission of two adjacent channels part, and when the transmitting terminal of wireless transmitting system and receiving terminal chip design, add the method that this channel switches, utilize repeating that first operating frequency cooperates with second operating frequency to increase by a deviation frequency, when channel switches, can continue the transmission data and reach.
Description of drawings
Fig. 1 is a kind of wireless transmitting system schematic diagram of one embodiment of the present invention;
Fig. 2 is the channel schematic diagram of an embodiment wireless transmitting system in the 802.11b frequency range;
Fig. 3 is the channel schematic diagram of another embodiment wireless transmitting system in the 802.11b frequency range;
Fig. 4 A is the indoor use channel schematic diagram of another embodiment wireless transmitting system in the 802.11a frequency range;
Fig. 4 B is the outdoor application channel schematic diagram of another embodiment wireless transmitting system in the 802.11a frequency range; And
Fig. 5 is channel switching flow figure of the present invention.
The main element symbol description
10 transmitting terminals, 20 receiving terminals
12 video/audio sources, 22 display unit
14,24 controllers, 11,21 frequency regulators
16,26 reflectors, 18,28 receivers
161,261 transmitting antennas, 181,281 reception antennas
CH1, CH2 ..., CH22 N channel (N from 1 to 22)
Embodiment
Please refer to Fig. 1 is a kind of wireless transmitting system of one embodiment of the present invention, and this system is made up of a transmitting terminal 10 (Access Point) and a receiving terminal 20 (Client) at least.Wherein, transmitting terminal 10 connects a video/audio source 12, reach a controller 14 with the audio-video signal that video/audio source 12 is provided, the audio-video signal of handling via controller 14 passes through a reflector 16 through its transmitting antenna 161 output signals, and a reception antenna 181 of a receiver 18 receives the signal that wireless remote control or receiving terminal sent, and needs mat one frequency regulator 11 to modulate the switching that can reach channel according to it.
The signal that receiving terminal 20 receives from transmitting terminal 10 by a dual-mode antenna 281, through the processing of receiver 28 with controller 24, be passed to a display unit 22 to play audio-video signal, receiving terminal 20 mats one frequency regulator 21 can cooperate transmitting terminal 10 to carry out channel switching again, and by the transmitting antenna 261 of reflector 26 its achievement is reached transmitting terminal.
Please refer to Fig. 2, is the channel schematic diagram of an embodiment wireless transmitting system in the 802.11b frequency range.Wherein, when the transmission or the receive frequency of wireless transmitting system are set on two channel center frequency in office, the signal that sent this moment can not interfere with each other, that is to say that the transmitted frequency when transmitting terminal is 2.412GHz, and the receive frequency of receiving terminal is 2.437GHz, like this signal sent of transmitting terminal, receiving terminal also can't receive smoothly, because of frequency between the two and can't connect, unless two ends all be on the same channel, just can receive smoothly.
And channel switching of the present invention is exactly an idea of utilizing covering frequence between channel, sets skew (off-set) frequency (or being called an offset units) and makes its maximum less than covering frequence.When transmitting terminal was desired to switch to adjacent channel, when cooperating every increase by one deviation frequency of transmitting terminal, the operating frequency value of just regulating receiving terminal made it identical, and when making that transmitting terminal is each and increasing by a deviation frequency unit, receiving terminal can both continue to receive bag.Therefore, reach the target that progressively former centre frequency is switched to adjacent purpose channel.
Explained below how wireless transmitting system is reached channel and switched in the 802.11b frequency range, as shown in the figure, suppose that the non-covering frequence (non-overlapping) in 802.11b is 2.412GHz, 2.437GHz, 2.462GHz, set one first channel CH1, one second channel CH2 and one the 3rd channel CH3 with it as centre frequency respectively, again with the difference of adjacent channel centre frequency again divided by a natural number N, a frequency values be set at an offset units, wherein offset units must be less than the maximum of the covering frequence of wantonly two adjacent channels.Suppose when N is 5, the difference that deducts the centre frequency 2.412GHz of first channel with the centre frequency 2.437GHz of second channel is 0.025GHz, set 0.025/5=0.005 (GHz)=5 (MHz) for a deviation frequency again, make two adjacent channels be subdivided into five frequency ranges again, each frequency range differs an offset units, as: the 1st frequency range is that 2.412GHz, the 2nd frequency range are 2.417GHz, by that analogy.
Suppose the transmitting terminal of present embodiment and the centre frequency 2.412GHz that receiving terminal initial setting primary frequency is all first channel, respectively called after first operating frequency and second operating frequency.When the user when watching image, when feeling to make that because of noise jamming picture quality is not good, export a channel switching instruction to transmitting terminal with remote controller, to require the communication channel between transmitting terminal and the receiving terminal to switch to another idle channels, idle channels is assumed to second channel again, and its centre frequency is a purpose frequency.
When the instruction of transmitting terminal reception switching channels, when first channel switches to second channel, can transmit user profile agreement (UDP) to receiving terminal, comprise data and channel among the UDP and changed notice, so that cooperating, second operating frequency switches to the purpose frequency; First operating frequency of transmitting terminal increases by a deviation frequency, and this moment, first operating frequency skipped to the 2nd frequency range by the 1st original frequency range, transmitting terminal and with the first operating frequency reposition with supervisory packet notice receiving terminal; Receiving terminal receiving management bag is regulated second operating frequency and is made it consistent with first operating frequency; The information that receiving terminal is finished adjusting returns to transmitting terminal with a packet; Transmitting terminal receives packet, and compares present place first operating frequency and whether equal the purpose frequency; Because this moment, first operating frequency was the 2nd frequency range, and the purpose frequency is the 6th frequency range, and first operating frequency is not equal to the purpose frequency, then transmitting terminal must be regulated its first operating frequency again, increase by a deviation frequency, and the repetition above-mentioned steps, equaling the purpose frequency until first and second operating frequency, the channel that promptly finishes wireless transmitting system switches.
Wherein, this transmitting terminal and receiving terminal continue the transmission data in the process of regulating its operating frequency position, promptly increase by a deviation frequency in transmitting terminal, but receiving terminal is not regulated second operating frequency as yet, at this moment, first operating frequency and second operating frequency still within the covering frequence scope, can't make transmitting terminal and receiving terminal in two frequencies that can not interfere with each other, so its transfer of data still can keep line.
When data are a view data, when the change of first operating frequency, transmitting terminal still continues the transmitted image data to receiving terminal, also regulates second operating frequency in the time of the receiving terminal image data processing, make display unit be play this view data, do not have the situation generation that picture is stagnated.
When shown in Figure 2, if natural number N is that the deviation frequency of 5 o'clock gained is excessive, after causing first operating frequency to increase offset units, when receiving terminal can't receive correct data, represent that promptly first operating frequency once moves too much, make the signal weakening that receiving terminal received, at this moment, second operating frequency of receiving terminal is can't fit adjustment consistent with first operating frequency.
At this moment,, the value of deviation frequency is reduced with increasing the value of natural number N, too faint with the signal of avoiding between transmitting terminal and receiving terminal, being transmitted.As shown in Figure 3, be the channel schematic diagram of another embodiment wireless transmitting system in the 802.11b frequency range.Suppose when N is 10, the difference that deducts the centre frequency of first channel with the centre frequency of second channel is 0.025GHz, set 0.025/10=0.0025 (GHz)=2.5 (MHz) for a deviation frequency again, make two adjacent channels be subdivided into ten frequency ranges again, each frequency range differs an offset units, as: the 1st frequency range is that 2.4120GHz, the 2nd frequency range are 2.4145GHz, by that analogy.
And its transmitting terminal and receiving terminal initial setting primary frequency are all the centre frequency 2.412GHz of first channel, are respectively first operating frequency and second operating frequency.When the instruction of transmitting terminal reception switching channels, will carry out the channel switching of wireless transmitting system according to the described principle of Fig. 2, then do not add to give unnecessary details at this.
Please refer to and Figure 4 shows that the channel schematic diagram of another embodiment wireless transmitting system in the 802.11a frequency range.As shown in the figure, in the 802.11a frequency range, can be divided into indoor (Fig. 4 A) and outdoor (Fig. 4 B) two kinds of frequencies, wherein non-covering frequence in indoor used frequency till the centre frequency 5.320GHz of the centre frequency 5.180GHz to the of the first channel CH1,15 channel CH15, in the centre frequency 5.805GHz of outdoor used frequency from the centre frequency 5.745GHz to the of the 16 channel CH16 22 channel CH22.
Again with the difference of adjacent channel centre frequency again divided by a natural number N, a frequency values be set at an offset units, wherein offset units must be less than the maximum of the covering frequence of wantonly two adjacent channels.Suppose that when N is 2 the difference that deducts the centre frequency 5.180GHz of first working channel with the centre frequency 5.200GHz of second channel is 0.02GHz, again with 0.02/2=0.01
(GHz)=10 (MHz) sets an offset units for, makes adjacent per 1 frequency range differ the value of an offset units, as: the 36th frequency range is that 5.180GHz, the 37th frequency range are 5.190GHz, by that analogy.
The channel switching principle of the transmitting terminal of present embodiment and receiving terminal is identical with the principle of above-mentioned 802.11b, so do not add to give unnecessary details at this.But if use the 802.11a frequency range, the value of its deviation frequency is when channel switches, and the audio-video quality of influence does not only need to get final product less than the maximum of covering frequence; If use the 802.11b frequency range, the value of its deviation frequency is when channel switches, and the more little meeting of its value makes that audio-video quality is good more, transmission range is long more, but the time of switching is of a specified duration more.
Please refer to Fig. 5 and be channel switching flow figure of the present invention.As shown in FIG., suppose the transmitting terminal 10 of present embodiment and the centre frequency that receiving terminal 20 initial setting primary frequencies are all first channel, be respectively first operating frequency and second operating frequency.When the user watches image, think that picture quality is not good, export a channel switching instruction to transmitting terminal, switch to another idle channels to require the communication channel between transmitting terminal and the receiving terminal with remote controller, idle channels is assumed to second channel again, and its centre frequency is a purpose frequency.
Receive the instruction (S11) of switching channels when transmitting terminal, when first channel switches to second channel, can transmit user profile agreement (UDP) to receiving terminal, comprise data and channel among the UDP and changed notice, receiving terminal receives UDP (S21), switches to the purpose frequency so that the preparation of second operating frequency cooperates; First operating frequency of transmitting terminal increases a deviation frequency (S13), and with the first operating frequency reposition be placed into beacon (Beacon) in, with supervisory packet notice receiving terminal (S15); Whether receiving terminal receiving management bag is compared first operating frequency and is equated with second operating frequency, if unequal, then regulate second operating frequency and makes it consistent with first operating frequency (S23); The information that receiving terminal is finished adjusting is back to transmitting terminal (S25) with a packet with the UDP form; Transmitting terminal receives packet (S17), and compares present place first operating frequency and whether equal purpose frequency (S19); If inequality, then transmitting terminal must be regulated its first operating frequency again, promptly repeats above-mentioned steps, equals this purpose frequency until first and second operating frequency, and the channel that promptly finishes wireless transmitting system switches.
In step S15~S23, when the deviation frequency that sets is excessive, can cause the data in the supervisory packet that transmitting terminal transmits, receiving terminal can't be correct reception, wireless transmitting system will dwindle the value of deviation frequency this moment, be about to primary frequency and purpose frequency difference divided by the increasing of the first Integer N value, deviation frequency is dwindled, and then makes the data that receiving terminal can normally receiving end/sending end sends.In the channel handoff procedure, beacon will be with every 100ms transmission primaries, to continue confirming that the transmission of data can not be interrupted again.
The present invention utilizes the scope of covering frequence can influence the signal transmission of two adjacent channels part, and when the transmitting terminal of wireless transmitting system and receiving terminal chip design, add the method that this channel switches, utilize repeating that first operating frequency cooperates with second operating frequency to increase by a deviation frequency, can continue to transmit data when channel switches and be implemented in.And unlike prior art when the switching channels, can be broken and need can continue to transmit data behind the line again again.

Claims (13)

1. wireless transmitting system, this system comprises:
One transmitting terminal optionally uses one first adjacent channel and one second channel to transmit data, and the centre frequency of this first channel is a primary frequency, and the centre frequency of this second channel is a purpose frequency; And
One receiving terminal, receive this data from this first channel, this transmitting terminal and this receiving terminal operate on one first operating frequency and one second operating frequency respectively, this first operating frequency and this second operating frequency are this primary frequency, wherein, when this transmitting terminal when this first channel switches to this second channel, this transmitting terminal increases by a deviation frequency in this first operating frequency, and it is consistent with this first operating frequency to regulate this second operating frequency, this transmitting terminal is this purpose frequency by repeating to increase this deviation frequency up to this first and second operating frequency.
2. wireless transmitting system as claimed in claim 1, wherein this deviation frequency is less than the maximum of the covering frequence of any two adjacent channels.
3. wireless transmitting system as claimed in claim 2, wherein this deviation frequency is that the difference of this primary frequency and this purpose frequency is again divided by one first Integer N.
4. wireless transmitting system as claimed in claim 3 wherein increases this deviation frequency when this first operating frequency, and this receiving terminal increases the value of this first Integer N can't receive correct data the time.
5. wireless transmitting system as claimed in claim 1, wherein this system also comprises a remote control, but this remote control of user's mat is controlled this transmitting terminal and is switched this first channel to this second channel.
6. wireless transmitting system as claimed in claim 1, wherein, this transmitting terminal increases in the place of its centre frequency frequency and continues to send these data in the process of a deviation frequency.
7. wireless transmitting system as claimed in claim 1, this receiving terminal also comprises a display unit, wherein these data are a view data, this receiving terminal receives after this view data handles, make this display unit be play this view data, wherein when this first operating frequency change, this transmitting terminal continues to transmit this view data.
8. the channel switching method of a wireless transmitting system, in order to make a transmitting terminal and a receiving terminal optionally use one first adjacent channel and one second channel to transmit data, the centre frequency of this first channel is a primary frequency, the centre frequency of this second channel is a purpose frequency, this transmitting terminal and this receiving terminal operate on one first operating frequency and one second operating frequency respectively, this first operating frequency and this second operating frequency are this primary frequency, and this method comprises following steps at least:
(1) user sends a channel switching instruction;
(2) this transmitting terminal receives this instruction, and transmits user profile agreement UDP to this receiving terminal, so that this first operating frequency switches to this purpose frequency;
(3) this of this transmitting terminal first operating frequency increases by a deviation frequency, and notifies this receiving terminal with this first operating frequency position with a supervisory packet;
(4) this receiving terminal receives this supervisory packet, regulates this second operating frequency, makes it identical with this first operating frequency;
(5) this receiving terminal information that adjusting is finished is back to this transmitting terminal with a packet;
(6) this transmitting terminal receives this packet, and compares this first operating frequency of present place and whether equal this purpose frequency;
(7) be not equal to this purpose frequency when this first operating frequency of this transmitting terminal place, repeat above-mentioned steps (3)~(6); And
(8) equal this purpose frequency until this first and second operating frequency, the channel that promptly finishes wireless transmitting system switches.
9. method as claimed in claim 8, wherein deviation frequency system is less than the maximum of the covering frequence of any two adjacent channels.
10. method as claimed in claim 9, wherein deviation frequency system utilizes the difference of this primary frequency and this purpose frequency to get divided by one first Integer N again.
11. method as claimed in claim 10, wherein in this step (3) and step (4), this transmitting terminal increases this deviation frequency at this primary frequency, and this receiving terminal increases the value of this first Integer N can't receive these correct data the time.
12. method as claimed in claim 8, wherein this channel switching instruction is for to switch to this second channel with this transmitting terminal from this first channel.
13. method as claimed in claim 8, the wherein transmission that this wireless transmitting system all keeps these data in above-mentioned arbitrary step.
CNB2005100923239A 2005-08-26 2005-08-26 Wireless transmission system and method for channel switching Expired - Fee Related CN100477778C (en)

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CNB2005100923239A CN100477778C (en) 2005-08-26 2005-08-26 Wireless transmission system and method for channel switching

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CN100477778C true CN100477778C (en) 2009-04-08

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CN117294372B (en) * 2023-11-23 2024-02-09 上海芯袖微电子科技有限公司 Frequency conversion control method, device and system

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Granted publication date: 20090408

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