METHOD AND DEVICE FOR DETERMINING TOGGLE SEQUENCE AND ERROR PATTERN BASED ON SOFT DECISION

• US 20160269148A1
• Filed: 02/17/2015
• Published: 09/15/2016
• Est. Priority Date: 02/17/2014
• Status: Active Grant

• Current Assignee: Yonsei University
• Original Assignee: Yonsei University
• Inventors: KIM, Jae Kwon, YUN, Ju Hee, KIM, Nu Li Byul
• Granted Patent: US 10,298,360 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0047 Decoding adapted to other signal detection operation in conjunction with sequence estimation or equalization H04L25/03286
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/1864 ARQ related signaling H04L1/1607 takes precedence
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end

Abstract

Provided is a method of determining a toggle sequence for error detection based on a soft decision value and a method and apparatus for determining an error pattern, and more particularly, to a method of determining an optimum toggle sequence and error pattern based on a soft decision value in order to allow for faster error (pattern) detection and correction. It is an object of the invention to implement low redundancy, less delay, and a receive-side error correction capability by combining advantages of the conventional ARQ scheme and the conventional FEC scheme using a soft decision reliability. For this purpose, according to a first embodiment of the present invention, in order to optimize the toggle sequence speed, there is provided a method of determining a toggle sequence such that bits are toggled sequentially in the order of a smaller sum of soft decision reliabilities to be toggled.

Claims

1. A method of determining an optimum toggle sequence depending on a reliability of a soft decision bit stream for a receive signal, the method comprising processes of:

setting a fundamental toggle sequence group; and

determining the toggle sequence such that bits are toggled sequentially on a smaller sum basis of soft decision reliabilities to be toggled using the fundamental toggle sequence group.

2. The method according to claim 1, wherein the fundamental toggle sequence (SEQ) is determined based on the following equation:

3. The method according to claim 1, wherein the process of determining the optimum toggle sequence includes a process of determining a sorting completion pointer (CRC_ptr) out of the fundamental toggle sequence group (SEQ) based on the following equation:

CRC_ptr←

find(SEQ=2<sup>s−

1</sup>).

4. The method according to claim 3, further comprising a process of detecting and checking an error whenever toggling is performed sequentially until the toggle sequence indicated by the sorting completion pointer (CRC_ptr),

wherein the receive signal includes an error detection bit.

5. The method according to claim 3, further comprising a process of determining a next sequence by determining a next toggle sequence group (SEQ^temp) from the fundamental toggle sequence group (SEQ) based on the following equation:

SEQ^temp←

SEQ+2<sup>s−

1</sup>.

6. The method according to claim 5, wherein the process of determining the optimum toggle sequence includes a process of determining a sorting range indicator (l_pos) out of the next toggle sequence group (SEQ^temp) based on the following equation:

7. The method according to claim 6, wherein the process of determining the optimum toggle sequence includes a process of sorting unidentified sequences on a smaller sum-of-reliabilities basis by calculating a sum of the reliabilities for each sequence ranging from the sequence (CRC_ptr+1) next to that indicated by the sorting completion pointer to the sequence (l_pos−

1) preceding the sorting range indicator.

8. The method according to claim 5, wherein the process of determining the next sequence includes a process of repeatedly determining the next sequence by determining the next toggle sequence group (SEQ^temp′

) by combining the fundamental toggle sequence group (SEQ) and the next toggle sequence group (SEQ^temp) into a next fundamental toggle sequence group (SEQ′

) and incrementing “

s”

.

9. The method according to claim 8, wherein, in the process of determining the next sequence, the next toggle sequence group is determined by reflecting a sequence sorted through the process of sorting unidentified sequences.

10. The method according to claim 8, wherein the process of determining the next sequence includes a process of updating the sorting completion pointer (CRC_ptr) by adding “

1”

to “

s”

.

11. The method according to claim 1, further comprising a process of detecting and checking an error whenever toggling is performed,

wherein the receive signal includes an error detection bit.

12. The method according to claim 11, wherein the error detection bit is a cyclic redundancy check (CRC) bit.

13. A method of determining an error pattern by comparing syndromes on a reliability basis in a received signal, the method comprising a process of, if an interrupt value is smaller than the number of error patterns of a first error pattern group (E_Nb), determining a second unsorted error pattern group (E_Nb+1′

) by substituting the (N_b+1)th bit with “

1”

for error patterns of the first error pattern group (E_Nb) until the interrupt value.

14. The method according to claim 13, wherein a second unsorted error pattern group (E_Nb+1′

) is determined by substituting the (N_b+1)th bit with “

1”

for overall error patterns of the first error pattern group (E_Nb) if the interrupt value is equal to or greater than the number of error patterns of the first error pattern group (E_Nb).

15. The method according to claim 13, wherein reliabilities of each error pattern of the second unsorted error pattern group (E_Nb+1′

) are determined by adding a reliability of the error pattern having only the (Nb+1)th bit set to “

1”

to each error pattern of the first error pattern group (E_Nb).

16. The method according to claim 15, wherein syndromes of each error pattern of the second unsorted error pattern group (E_Nb+1′

) are determined by performing exclusive OR (XOR) operation between a syndrome of the error pattern having only the (Nb+1)th bit set to “

1” and

syndromes of each error pattern of the first error pattern group (E_Nb).

17. The method according to claim 16, wherein the second error pattern group (E_Nb+1) is determined by sorting error patterns ranging from an error pattern next to that indicated by the first sorting completion pointer (ptr_Nb) to the last error pattern of the second unsorted error pattern group (E_Nb+1′

) on a smaller reliability basis using a mergesort algorithm.

18. The method according to claim 17, wherein the second error pattern group (E_Nb+1) is determined by applying a mergesort algorithm just until a maximum error correction pattern number (N_max) if the number of error patterns sorted through the mergesort algorithm is greater than the maximum error correction pattern number (N_max).

19. The method according to claim 17, wherein the mergesort algorithm is applied to a first mergesort group ranging from an error pattern next to that indicated by the first sorting completion pointer (ptr_Nb) to the last error pattern of the first sorted error pattern group (E_Nb) and a second mergesort group ranging from the first error pattern to the last error pattern of the second unsorted error pattern group (E_Nb+1′

).

20. The method according to claim 18, wherein the mergesort algorithm is applied just until the last error pattern of any one of the first and second mergesort groups.

21. The method according to claim 18, wherein each syndrome of the error patterns ranging from the error pattern of the first error pattern group (E_Nb) indicated by the first sorting completion pointer (ptr_Nb) to the error pattern of the second error pattern group (E_Nb+1) indicated by the second sorting completion pointer (ptr_Nb+1) is compared with a hard decision syndrome of the received signal.

22. The method according to claim 20, wherein, if the second sorting completion pointer (ptr_Nb+1) is greater than the maximum error correction pattern number (N_max), the syndromes are compared just until the error pattern corresponding to the maximum error correction pattern number (N_max).