WO2005117272A1 - ビタビ復号装置、およびビタビ復号方法 - Google Patents
ビタビ復号装置、およびビタビ復号方法 Download PDFInfo
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- WO2005117272A1 WO2005117272A1 PCT/JP2005/002292 JP2005002292W WO2005117272A1 WO 2005117272 A1 WO2005117272 A1 WO 2005117272A1 JP 2005002292 W JP2005002292 W JP 2005002292W WO 2005117272 A1 WO2005117272 A1 WO 2005117272A1
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- traceback
- viterbi decoding
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
- H03M13/37—Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35
- H03M13/39—Sequence estimation, i.e. using statistical methods for the reconstruction of the original codes
- H03M13/3994—Sequence estimation, i.e. using statistical methods for the reconstruction of the original codes using state pinning or decision forcing, i.e. the decoded sequence is forced through a particular trellis state or a particular set of trellis states or a particular decoded symbol
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
- H03M13/37—Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35
- H03M13/39—Sequence estimation, i.e. using statistical methods for the reconstruction of the original codes
- H03M13/41—Sequence estimation, i.e. using statistical methods for the reconstruction of the original codes using the Viterbi algorithm or Viterbi processors
- H03M13/4161—Sequence estimation, i.e. using statistical methods for the reconstruction of the original codes using the Viterbi algorithm or Viterbi processors implementing path management
- H03M13/4169—Sequence estimation, i.e. using statistical methods for the reconstruction of the original codes using the Viterbi algorithm or Viterbi processors implementing path management using traceback
- H03M13/4176—Sequence estimation, i.e. using statistical methods for the reconstruction of the original codes using the Viterbi algorithm or Viterbi processors implementing path management using traceback using a plurality of RAMs, e.g. for carrying out a plurality of traceback implementations simultaneously
Definitions
- the present invention relates to a Viterbi decoding device that corrects data transmitted by a convolutional code using Viterbi decoding and a Viterbi decoding method.
- the convolutional encoder 201 holds information bits I sequentially input in a shift register composed of D1 to D6, and stores the previously input 6 information bits and the current information bits. From the input information bit I, two code bits C0 and C1 are generated.
- the convolutional encoder 201 holds information bits I sequentially input in a shift register composed of D1 to D6, and stores the previously input 6 information bits and the current information bits. From the input information bit I, two code bits C0 and C1 are generated.
- D6 is represented by STATE ⁇ D1, D2, D3, D4, D5, D6 ⁇ .
- Termination bits 01000111 are sequentially input to the convolutional encoder indicated by 201 in FIG. 2 (a). Bits before and after the termination bit can be 0 or 1, so they are set to X.
- Patent Document 1 JP-A-2000-183756
- Patent Document 2 JP-A-9-191258
- the present invention has an object to prevent the propagation of error correction capability before and after a termination code without increasing the circuit scale, and to further increase the correction capability compared to the related art.
- the goal is to improve
- the invention of claim 1 provides a Viterbi decoding device that decodes a convolutional code terminated by a predetermined termination value, by generating a branch metric from an input code, An ACS means for generating a path metric and a path selection signal at each node; a traceback memory for storing the path selection signal output by the ACS means; and an end timing of the input code, and A termination timing detecting means for outputting a termination control signal for controlling a traceback process performed on the traceback memory, a path selection signal output from the traceback memory, and the termination control signal, and A traceback unit that performs the traceback processing using a pointer for performing the traceback processing.
- the termination control signal indicates a termination processing period, a forced value based on the termination value is set in the pointer regardless of the bus selection signal.
- the invention according to claim 2 is the Viterbi decoding device according to claim 1, wherein the trace-back unit has a read rate of M (M is an integer of 2 or more) times a write rate of an input code in the trace-back memory. And performs the traceback.
- M is an integer of 2 or more
- the trace-back memory includes a plurality of banks, and the trace-back unit stores the plurality of banks by pipeline processing.
- the trace-back processing is performed using the divided trace-back memories, and the termination timing detecting means detects, when the termination value is divided into two banks, two or one termination code periods.
- the traceback unit sets a forced value based on the termination value in the pointer during the two or one termination code periods, and performs traceback processing.
- the termination timing detecting means includes counter means for counting each time code data is input, and When the convolutional code terminated by the value is written to the traceback memory, the value of the counter value of the counting means is also calculated to obtain the termination code period, and the traceback unit detects the termination code period detected.
- a forced value based on the closing value is set in the pointer, and a traceback process is performed.
- the termination timing detection means includes counter means for counting each time code data is input, and includes a traceback start signal and a termination signal.
- a terminating period division detecting means for detecting that the terminating code period is divided into two from the code signal, and a step of writing the convolutional code terminated to a determined closing value into the traceback memory. Calculating the power of the counting means and calculating the end code period by calculating the one end code period or the end code period detected as being divided into two. In the code period, a forced value based on the closing value is set in the pointer.
- the termination timing detecting means writes a leading value of a convolutional code terminated to a predetermined termination value to the traceback memory.
- an address storing means for storing the address of the trace-back memory.
- the stored write address is compared with an address at the time of reading the trace-back memory to detect the termination processing period.
- the means sets a forced value based on the end value in the pointer during the detected end code period.
- the invention of claim 7 is the Viterbi decoding device according to claim 3, wherein the termination timing detection means, when the termination period is divided into two banks, sets the start code of the termination code of the first bank.
- Address storage means for storing an address at the time of writing the first value
- address storage means for storing an address at the time of writing the last value of the terminating code of the second bank, a stored write address
- Address comparison means for detecting the termination processing period by comparing an address at the time of reading out the trace-back memory; In the detected termination code period, a forced value based on the termination value is set in the pointer.
- the invention according to claim 8 is the Viterbi decoding device according to claim 3, wherein the traceback start and end addresses in the traceback memory are fixed, and the termination timing detection means includes: Address storage means for storing an address at the time of writing the last value of the end code of the bank of the second bank, and address storage means for storing an address at the time of writing the first value of the end code of the second bank. Address comparison means for detecting the termination processing period by comparing the write address read with the address at the time of reading out the trace-back memory, and the furnace race-back section includes the detected period. , A forcible value based on the closing value is set in the pointer.
- the invention of claim 9 is the Viterbi decoding device according to claim 2 or 3, wherein the termination timing detecting means is configured to write the convolutional code terminated to a predetermined termination value to the traceback memory.
- 1-bit judgment data indicating that the code is a termination code
- the unit sets a forced value based on the closing value in the pointer during the detected period.
- the invention according to claim 10 is the Viterbi decoding device according to claim 2 or 3, wherein the termination timing detecting means writes the convolutional code terminated to a predetermined termination value to the trace back memory.
- the invention of claim 11 is the Viterbi decoding device according to any one of claims 1 to 10, wherein in the case of a code sequence in which the closing value is variable, the variable value according to the closing value is variable.
- a twelfth aspect of the present invention is the Viterbi decoding device according to any one of the first to eleventh aspects, wherein the traceback pointer is constituted by a FIFO (Fast In Fast Out), and the termination timing detecting means is provided.
- the termination processing period detected in the step (c) there is provided a means for inputting a forced value as an input bit of the FIFO irrespective of a bus selection signal, and the traceback unit is configured to output a forced value based on the termination value. Is set to the pointer.
- a thirteenth aspect of the present invention is the viterbi decoding apparatus according to any one of the first to twelfth aspects, wherein the termination period detecting means comprises a termination processing period divided into one or two detected periods. And the traceback unit sets a forced value to the traceback pointer only in the partial period.
- the invention according to claim 14 is a Viterbi decoding method for decoding a convolutional code terminated by a predetermined termination value, wherein an actual traceback is performed at the time of traceback of codes before and after the termination code. Regardless of the result, the forced value based on the closing value is set in the traceback pointer.
- the termination timing in the convolutional code terminated to a predetermined termination value is detected, and the traceback memory is read therefrom.
- FIG. 1 is a configuration diagram of a Viterbi decoding device according to the first to fifth embodiments of the present invention.
- FIG. 2 (a) is a configuration diagram of a convolutional encoder according to the first to fifth embodiments of the present invention.
- FIG. 2 (b) is a trellis diagram of a convolutional encoder according to the first to fifth embodiments of the present invention.
- FIG. 3 is a flowchart of the convolutional encoder according to the first to fifth embodiments of the present invention.
- FIG. 4 is a conceptual diagram of a trace-back process according to the first embodiment of the present invention.
- FIG. 5 is a configuration diagram of the termination timing detection unit according to the first embodiment of the present invention.
- FIG. 6 is a timing chart of a traceback process according to the first embodiment of the present invention.
- FIG. 7 is a flowchart of a traceback process according to the first embodiment of the present invention.
- FIG. 8 is a configuration diagram of a termination timing detection unit according to the second embodiment of the present invention.
- FIG. 9 is a conceptual diagram of a traceback process according to the second embodiment of the present invention.
- FIG. 10 is a timing chart of a trace-back process according to the second embodiment of the present invention.
- FIG. 11 is a flowchart of a trace-back process according to the second embodiment of the present invention.
- FIG. 12 is a configuration diagram of a termination timing detection unit according to the third embodiment of the present invention.
- FIG. 13 is a conceptual diagram of a traceback process according to a fourth embodiment of the present invention.
- FIG. 14 is a conceptual diagram of a traceback process according to a fifth embodiment of the present invention. Explanation of reference numerals
- FIG. 1 is a block diagram showing a configuration of a Viterbi decoding device according to Embodiment 1 of the present invention.
- the Viterbi decoder of FIG. 1 is for decoding a terminated convolutional code.
- the ACS unit 100 also generates a branch metric for the input convolutional coding power, and generates a generated branch metric power path metric and a path selection signal at each node.
- the trace back memory 101 stores a path selection signal output from the ACS unit 100, and is configured by, for example, a normal RAM (Random Access Memory).
- Maximum likelihood noise determination section 102 determines the most probable path from the path metric and the path selection signal output from ACS means 100.
- Termination timing detection section 103 detects a termination processing period of the input code at the time of traceback from a signal indicating that the input convolutional code is a termination code, and a termination control signal for controlling traceback processing. Outputs 110.
- the traceback unit 104 receives the path selection signal, the termination control signal 110, and the termination value output from the traceback memory 101, and performs traceback using a pointer for traceback.
- the traceback unit 104 includes a forced value generation unit 105 that generates a forced value to be input to the pointer unit 106 from the termination control signal 110 output from the termination timing detection unit 103 and a variable termination value, and a maximum likelihood.
- the maximum likelihood path output from the path determination unit 102, the code output from the coded bit generation unit 108, and the forced value output from the forced value generation unit 105 are input, and a pointer for tracing back is specified.
- a pointer section 106 composed of a FIFO (First In First Out memory) to output, a selection section 107 for reading out the most probable path selection signal from the traceback memory 101 using a pointer output from the pointer section 106, and a selection section
- the path selection signal output from 107 also includes a coding bit generation unit 108 for generating coding bits.
- LIFO (Last In First Out memory) 109 is a code output from the traceback unit 104. The decoding bit is stored and the decoding result is output.
- a signal indicating whether or not the code being input is a termination code is determined. If the input convolutional code is not a termination code, a traceback similar to that of a conventional Viterbi decoding device is performed. Perform processing. (For example, see Patent Document 2)
- the traceback processing similar to the conventional one is briefly described according to the configuration of the present circuit.
- the ACS unit 100 generates a branch metric based on the input convolutional code, and further uses this branch metric. Then, the path reaching each node of the trellis diagram is selected, and the path metric and the path selection signal for each node are updated. Among them, the path selection signal is stored in the traceback memory 101.
- the maximum likelihood path determination unit 102 selects a path with higher likelihood by comparing path metrics for each node.
- the determination result of the maximum likelihood nos determining section 102 is given as a pointer value of the pointer section 106 at the time when the traceback is started in the traceback section 104.
- the traceback unit 104 at the start of the traceback, the node referred to by the pointer value given by the maximum likelihood path determination unit 102 as described above is selected by the selection unit 107, and the traceback memory 101
- the path selection signal at the node indicated by the pointer is read and input to the encoding bit generation unit 108.
- the code generated by the code generation bit generation unit 108 is input to the LIFO 109 and simultaneously to the pointer unit 107, and is used for updating the pointer.
- the pointer section 106 is configured by a FIFO for sequentially inputting a noise selection signal.
- a pointer value is obtained from a path selection signal by calculation or a table based on a code generator polynomial.
- the code input to the LIFO 109 is output as decoded data after the completion of the traceback. Through these processes, the convolutional code is decoded.
- variable closing value 01000111
- the code sequence is input to the decoder without being affected by the transmission path at all, and considering that this code is traced back, the nodes of the trellis diagram are shown in FIG. In the reverse order of the transition of the STATE value during encoding,
- the transmitted signal is affected by noise on the transmission line, so that the signal encoded by the encoder and the input signal of the decoding device are not the same, and the ACS circuit
- the path metric and path selection signal determined at 100 may have different values than the ideal value.
- the termination code input in termination timing detection section 103 is traced back (13) — (1). Then, the finalization control signal 110 is output, and the ideal STATE at that time determined by the finalization value, the forced value is used without using the path selection signal extracted from the traceback memory 101. Is generated by the forced value generation unit 105, and the pointer unit 106 performs traceback using the forced value.
- the time is a symbol rate: a value obtained by re-specifying.
- the time intervals of the times T0, Tl, # 2, # 3, # 4, and # 5 correspond to the time intervals at which # path selection signals are input or output to the traceback memory 101.
- the path selection signal stored in memory 101A corresponds to time T3-T4-1.
- T0 + X and T0 + X + Y denote the times A and B at which the beginning and end of this termination sequence are stored, respectively, and the times A "and B" at which they are extracted are T4 X, and T4 X—Y.
- M is determined by the traceback length
- Y is the number of termination code bits N-1 and is a fixed value depending on the system. Therefore, if only X is obtained, the time at which the path selection signal of the termination code is extracted can be known.
- termination time detection section 103 detects the time at which the path selection signal of the termination code is taken out based on this, generates termination processing control signal 110, and generates the forced value generation section. Output to 105.
- FIG. 5 shows a configuration diagram of termination timing detection section 103 according to the first embodiment.
- the ACS unit 100 also generates a branch metric for the input convolutional code power, and generates a path metric and a noise selection signal at each node for the generated branch metric power.
- the trace back memory 101 stores a path selection signal output from the ACS unit 100, and is configured by, for example, a normal RAM (Random Access Memory).
- Maximum likelihood path determination section 102 determines the most probable path from the path metric and the path selection signal output from ACS means 100.
- Termination timing detection section 103 detects a termination processing period of the input code at the time of traceback from a signal indicating that the input convolutional code is a termination code, and a termination control signal for controlling the traceback processing. Outputs 110.
- the traceback unit 104 receives the path selection signal, the termination control signal 110, and the termination value output from the traceback memory 101, and performs traceback using a pointer for traceback.
- the trace-back unit 104 outputs the termination control signal 1 output from the termination timing detection unit 103.
- a forced value generation unit 105 that generates a forced value to be input to the pointer unit 106 from 10 and the variable end value, a maximum likelihood path output by the maximum likelihood path determination unit 102, and an output from the coded bit generation unit 108.
- a pointer 106 composed of a FIFO (First In First Out memory) that receives a code to be output and a forced value output from the forced value generator 105 and outputs a pointer for tracing back, and a pointer A selector 107 for reading out the most probable path selection signal from the trace back memory 101 using the pointer output from 106, and a code selection bit generation for generating a code selection bit for the path selection signal output from the selection unit 107. It has a part 108 and
- a LIFO (Last In First Out memory) 109 stores the encoding bits output from the trace-back unit 104, and outputs a decoding result.
- FIG. 6 shows a timing chart of the operation of termination timing detection section 103 having the above configuration.
- the counter A 503 and the counter B 504 are started by the logical product of the traceback start signal 500 due to the switching of the memories 101A, 101B, 101C, and 101D and the termination period end signal 501 of the termination processing mode detection unit 505. , Symbol rate: let each f count. At the rising edge of the signal 502 indicating that the input convolutional code is a termination code, the value of the counter A is held as indicated by 600. Assuming that the value of the counter A at this time is C1, when the value C2 of the counter B indicates 4M-CI-N + 1—4M-C1 as in 601 (1313) in the processing mode detection unit 505 ) —Generates and outputs the termination processing control signal 110 indicating the state of (6).
- the forced value generation unit 105 generates a forced value based on the final processing control signal 110 and the input forced value.
- FIG. 7 shows a flowchart of the nodes of the trellis diagram and the node selection signal read from the trace back memory 101 at that time during the termination processing period.
- the node immediately before the termination processing period is ⁇ 000000 ⁇ and the termination value is 01000111 will be described.
- the case where the node is in any other state can be similarly described.
- Reference numeral 700 denotes a node immediately before the termination processing period, and indicates that the pointer unit 106 configured by the FIFO is in the state of ⁇ 000000 ⁇ .
- the path selection signal fetched from the traceback memory 101 by the selection unit 104 is 0, and the After performing the lock processing, the node that will transition next should transition to the state of ⁇ 000000 ⁇ indicated by 701 in FIG.
- the termination processing control signal 110 output from the termination timing detection unit 103 indicates the timing of (13), so that 1 is input as a forced value instead of this path selection signal. It leads to the state of ⁇ 000001 ⁇ shown in 702.
- the node selection signal read at the node indicated by 702 is 0, and the force termination processing control signal 110, which should transition to the state of ⁇ 000010 ⁇ indicated by 703, indicates (12). Entering 1 as a forced value instead of a signal leads to the state of ⁇ 000011 ⁇ shown at 704.
- a forced value corresponding to the time indicated by the termination processing control signal 110 is created until the state ⁇ 0100010 ⁇ indicated by 705. Then, instead of the extracted path selection signal, the signal is input to the FIFO of the pointer section 106, and the signal is guided to the correct node. In other words, in the period of (13) — (6),
- the pointer by controlling the pointer at the time of inputting the termination code, in a system in which the reception characteristics change with the termination code as a boundary, the characteristic degradation in the sequence with a high error rate is reduced to the sequence with a low error rate Influence can be prevented, and the error correction capability can be improved.
- an arbitrary fixed node may be selected as a force start pointer using the output result of the maximum likelihood path determination unit 102 as a start pointer at the start of traceback.
- a power that sacrifices some error correction capability A configuration for using the output result of the maximum likelihood path determination unit as the start pointer can be omitted.
- Embodiment 1 a force using two counters, one counter, and one cow It is also possible to hold the value of the counter B 504 in a storage device by ANDing the traceback start signal 500 and the termination period end signal 501 of the termination processing mode detection unit 505 as a counter value retention device. it can.
- the forced value generation unit 105 that generates a forced value based on the fixed value omits the input of the forced value and a part related thereto. can do.
- the termination timing of a convolutional code terminated to a predetermined termination value is detected, and the termination timing is determined based on the termination timing.
- the traceback pointer is given a forced value determined from the predetermined termination value, which makes it possible to prevent the propagation of deterioration of error correction capability before and after the termination code without causing a large increase in circuit size.
- an effect that accurate Viterbi decoding can be performed can be obtained.
- FIG. 8 shows a configuration diagram of termination timing detection section 803 in the second embodiment.
- This configuration is obtained by adding a termination period division detecting section 800 to the termination timing detecting section 103 of the first embodiment.
- the processing in the case where the termination processing period is divided into two is defined as the period P—Q of the time TO—T1-1 in the memory 101A and the period R—S of the time T1 ⁇ T2-1 in the memory 101B.
- the case where the end code is divided and input will be described as an example.
- time points P, Q, R, and S are respectively represented by P: T0 + X, Q: T1—1, R: T1, and S: T0 + X.
- FIG. 10 shows a timing chart.
- the counter A503 and the counter B504 are started by the logical product of the traceback start signal 500 due to the switching of the memories 101A, 101B, 101C, and 101D and the termination period end signal 501 of the termination processing mode detection unit 505, and the symbol rate is: And let them count.
- the value of the counter A503, such as 1000, is held by the termination code signal 502 indicating that the input convolutional coding power is the beginning of the termination code.
- the trace-back start signal 500 is received, so that the termination period division detector 800 detects division of the termination period, and the processing mode detection unit 505 sends the division of the termination period. To inform.
- the period of 3M-4M-C1 is the period of (7) and (6)
- the period of 5M-1 and 6M-N-C1 is the period of (13)-(8).
- the termination processing control signal 810 is also output during that period.
- the forced value generation unit 105 generates a forced value based on the termination processing control signal 810.
- FIG. 11 shows a flowchart of the nodes of the trellis diagram and the node selection signal read from the traceback memory 101 at that time during the termination processing period.
- the left side of the figure shows the traceback in the memory 101A between times T3 and T4-1, and the right side of the figure shows the traceback in the memory 101B between the times T4 and T5.
- Reference numeral 1102 in FIG. 11 denotes a node at the start of traceback at time T3 to T4-1.
- the output of the maximum likelihood path determination unit 102 writes all bits of the pointer constituted by the FIFO. Change.
- the termination processing control signal 810 output from the termination timing detection section 803 indicates the timing of (7), thereby forcibly replacing the output of the maximum likelihood noise determination section 102 with FIG. As shown in 1103, the state of ⁇ 110001 ⁇ is given.
- the termination processing control signal 810 output from the termination timing detection unit 803 is a state where all bits of the pointer are not determined, as in (13)-(8) and (5)-(1), when the traceback starts.
- the termination processing control signal 810 is used instead of the path selection signal in the same manner as when the termination period is not divided.
- Use the forcing value generated as input to the FIFO That is, in the case of this example, the state of ⁇ 110001 ⁇ shown by 1103 in FIG. 11 is led to the state of ⁇ 100010 ⁇ shown by 1104.
- the order of (7) 1 (6) 0 and the first half of the termination code, which is reversed, is given as an input to the FIFO of the pointer section. .
- the forced value generated based on the termination processing control signal 810 is Used as FIFO input. That is, in the case of this example, the state of ⁇ 000000 ⁇ shown at 1105 in FIG. 12 is led to the state of ⁇ 111000 ⁇ shown at 1106. That is, in the period of (13)-(8), the order is reversed in the latter half of the terminating code, such as (13) 1 (12) 1 (11) 1 (10) 0 (9) 0 (8) 0 This is given as an input to the FIFO of the pointer section 106.
- the termination processing control signal 810 changes, and the period and value of the forced value also change. That said, the operation is the same.
- each period is considered in consideration of the fact that the termination code is divided. Since the forced value is set, the termination code can be correctly traced back, and an effect that the error correction capability can be more improved than in the first embodiment can be obtained.
- the third embodiment is the same as the second embodiment except for the configuration and operation of the termination timing detection unit, and thus the description of these processes is omitted.
- FIG. 12 shows the configuration of termination timing detection section 1213 in the third embodiment.
- [0101] 1200—1203 are each required time to the traceback memory 101 where the terminating code is stored. Are the address storage devices A to D for storing the write address in the storage device.
- Reference numeral 1204 denotes an address comparing unit that compares the address of the trace-back memory 101 with the address stored in the address storage devices A to D.
- Reference numeral 1215 denotes a processing mode detection unit that generates a termination processing control signal 1210 from the output of the address comparison unit 1204.
- the address storage device A 1200 stores the write address AD_p of the trace back memory 101 at the rising edge (time P) of the termination code signal 502.
- the address storage device B 1201 stores the write address AD_q of the trace-back memory 101 at the rise of the trace-back start signal 1212 (time Q).
- the address storage device C 1202 stores the write address AD_r of the traceback memory 101 at the fall (time R) of the traceback start signal 500.
- the address storage device D 1203 stores the write address AD_s of the trace-back memory 101 at the falling edge (time S) of the termination code signal 502.
- the address comparing unit 1205 compares the address: AD_p—AD_s stored in the address storage device A-D with the read address: AD_m of the trace-back memory 101, and after storing, By confirming the coincidence between the stored address and the read address, it is detected that the path selection signal written at each time point of PS is read. In other words, after comparing and storing AD_m and AD_p, the next matching time is P ". Similarly, comparing and comparing AD_m and AD_q—AD_s, and storing, The next matching time is Q "-S".
- the processing mode detection unit 1215 Based on the time detected by the address comparison unit 1205, the processing mode detection unit 1215 causes the processing mode detection unit 1215 to perform the termination processing control signal indicating the state (13)-(6), as in the second embodiment. 1210 is output to the forced value generation unit 105. If the traceback start point is (5)-(1), the termination processing control signal 1210 is output to the forced value generation unit 105 even during that period.
- the device and operation of the address storage device A 1200 may be reduced by sacrificing a slight improvement in error correction capability. Becomes possible.
- the configuration is such that the address of the trace-back memory 101 at the start and end of the trace-back is fixed, and the fixed value is stored in the address comparing unit 1204 by the address storage device B 1201 and the address storage device C.
- the devices and operations of the address storage device B 1201 and the address storage device C 1202 can be reduced.
- the Viterbi decoding device when the termination period is divided into two banks in the termination timing detection means, the first symbol of the termination code of the first bank is used.
- the last value of the end code of the first bank, the first value of the end code of the second bank, and the last value of the end code of the second bank respectively Address storing means for storing the address of the trace-back memory, and comparing the stored write address with the address at the time of reading out the trace-back memory to detect the termination processing period.
- the forced value based on the termination value is set in the pointer, so that it is possible to prevent the propagation of the deterioration of the error correction capability before and after the termination code, and to perform the Viterbi decoding with high accuracy. Door can effect is obtained.
- the fourth embodiment is the same as the second embodiment except for the configuration and operation of the trace-back memory and the termination timing detector, and thus the description thereof is omitted.
- the number of bits of the traceback memory 101 is extended by the number of termination information bits as compared with the previous embodiment, and the conventional path selection signal
- the information (1)-(13) indicating the termination state is sequentially stored as shown in the termination information bit write 1301. .
- the fourth embodiment in addition to the number of bits of the path selection signal, four bits of the termination information bit are extended and stored in the traceback memory 1301.
- read termination information bit 1302 path selection in traceback is performed.
- the termination information bit is read at the same time, and the read termination information bit is used in the same manner as the termination processing control signals 810 and 1210 in the second and third embodiments.
- the end timing can be detected without the end timing detectors 803 and 1213 in the third embodiment.
- (1) one (13) indicating the termination state is stored in the traceback memory 101 as 4-bit termination information at the same time as the start of recording in the traceback memory 101.
- the end period is divided by turning the counter, it is detected how many steps the counter value power is divided into, and the forcible value generation unit 105 divides the counter value power in the same manner as in the second and third embodiments.
- the termination timing detecting means when writing the convolutional code terminated to the determined termination value to the trace-back memory, sets the code to Judgment data consisting of a plurality of bits or one bit indicating a termination code is written into the traceback memory simultaneously with the convolutional code, and when the convolutional code is read, the judgment data is read out at the same time, and termination is performed using the judgment data.
- a forced value based on the closing value is set in the pointer, and therefore, as in Embodiment 13 above, before and after the closing code. It is possible to prevent the propagation of the error correction capability of the error correction and to perform the Viterbi decoding with high accuracy.
- traceback is performed by pipeline processing using a traceback memory having a plurality of banks.
- an input is provided to the traceback memory.
- processing is performed with a single bank of traceback memory. tray Except for the timing and the number of times of the sub processing, the processing is the same as that of the fourth embodiment, and the description of these processing is omitted.
- the path selection signal is stored in the trace back memory consisting of one bank from time TO, and from time T1-1 when M signals are written, Before the time T1 when the path selection signal is written, the trace-back processing is performed using the node selection signal stored at time TO—T1-1 as shown at 1401 as shown at 1401. The convolutional code at the time when the selected signal is written is decoded.
- the path selection signal by the next convolutional code is written to the address at which the path selection signal was stored at the time TO decoded earlier, and the same as before, the next By the time T1 + 1 when the path selection signal is written, traceback processing is performed using the path selection signal stored at time T0 + 1-T1 as shown at 1402, and at time T0 + 1 The convolution code at the time when the path selection signal is written is decoded.
- a path selection signal by the next convolutional code is written to the address storing the path selection signal at time T0 + 1, which was previously decoded, and T1 From +1 to time T1 + 2 when the next path selection signal is written, traceback processing is performed using the path selection signal stored at time T0 + 2—T1 + 1 as shown at 1403.
- the decoding of the convolutional code at the time when the path selection signal is written at time T0 + 2 is performed.
- the termination information bit is stored in the traceback memory as in the fourth embodiment, and based on this information, As in the previous embodiments, the error correction capability can be improved by creating a forced value and using it in place of the noise selection signal.
- the Viterbi decoding device uses a trace back memory having a plurality of banks, and does not perform trace back by pipeline processing. Access at M times the read rate of In this way, processing can be performed with one bank of traceback memory.
- the termination information bit is stored in the trace-back memory, and a forcible value is created based on the termination information bit and used in place of the path selection signal, so that errors before and after the code can be obtained. This makes it possible to prevent the propagation of the correction capability from being deteriorated, thereby providing an effect of enabling accurate Viterbi decoding.
- the Viterbi decoding device and Viterbi decoding method according to the present invention can prevent error correction characteristics from deteriorating when a convolutional code subjected to termination processing is decoded, and are useful as a demodulation circuit and a demodulation method for digital television.
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Abstract
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Priority Applications (4)
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BRPI0511576-0A BRPI0511576A (pt) | 2004-05-27 | 2005-02-16 | aparelho de decodificação de viterbi e método de decodificação de viterbi |
JP2006513808A JP4580927B2 (ja) | 2004-05-27 | 2005-02-16 | ビタビ復号装置、およびビタビ復号方法 |
EP05710242A EP1755228A4 (en) | 2004-05-27 | 2005-02-16 | VITERBI DECODING DEVICE AND VITERBI DECODING METHOD |
US11/597,541 US7861146B2 (en) | 2004-05-27 | 2005-02-16 | Viterbi decoding apparatus and Viterbi decoding method |
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JP2004-158260 | 2004-05-27 | ||
JP2004158260 | 2004-05-27 |
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WO2005117272A1 true WO2005117272A1 (ja) | 2005-12-08 |
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PCT/JP2005/002292 WO2005117272A1 (ja) | 2004-05-27 | 2005-02-16 | ビタビ復号装置、およびビタビ復号方法 |
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US (1) | US7861146B2 (ja) |
EP (1) | EP1755228A4 (ja) |
JP (1) | JP4580927B2 (ja) |
CN (1) | CN1957533A (ja) |
BR (1) | BRPI0511576A (ja) |
WO (1) | WO2005117272A1 (ja) |
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US8301990B2 (en) * | 2007-09-27 | 2012-10-30 | Analog Devices, Inc. | Programmable compute unit with internal register and bit FIFO for executing Viterbi code |
CN101889401B (zh) * | 2007-10-26 | 2014-12-31 | 高通股份有限公司 | 优化的维特比解码器和全球导航卫星系统接收器 |
KR101462211B1 (ko) * | 2008-01-30 | 2014-11-17 | 삼성전자주식회사 | 이동통신 시스템의 복호 장치 및 방법 |
CN105634505A (zh) * | 2014-11-27 | 2016-06-01 | 航天恒星科技有限公司 | 多用户编码复用方法及装置 |
TWI729755B (zh) * | 2020-04-01 | 2021-06-01 | 智原科技股份有限公司 | 接收器與應用在接收器中的交織碼調變解碼器及相關的解碼方法 |
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JP3747604B2 (ja) * | 1997-12-19 | 2006-02-22 | ソニー株式会社 | ビタビ復号装置 |
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- 2005-02-16 WO PCT/JP2005/002292 patent/WO2005117272A1/ja not_active Application Discontinuation
- 2005-02-16 US US11/597,541 patent/US7861146B2/en not_active Expired - Fee Related
- 2005-02-16 CN CNA2005800168919A patent/CN1957533A/zh active Pending
- 2005-02-16 BR BRPI0511576-0A patent/BRPI0511576A/pt not_active IP Right Cessation
- 2005-02-16 EP EP05710242A patent/EP1755228A4/en not_active Withdrawn
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JP2001024717A (ja) * | 1999-07-07 | 2001-01-26 | Matsushita Electric Ind Co Ltd | ターボ復号装置及び繰り返し復号方法 |
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EP1755228A4 (en) | 2008-04-16 |
CN1957533A (zh) | 2007-05-02 |
BRPI0511576A (pt) | 2008-01-02 |
EP1755228A1 (en) | 2007-02-21 |
JPWO2005117272A1 (ja) | 2008-04-03 |
US7861146B2 (en) | 2010-12-28 |
US20070234190A1 (en) | 2007-10-04 |
JP4580927B2 (ja) | 2010-11-17 |
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