Wireless electronic device with a decoder and associated methods
View Patent ↗A method for operating a decoder includes receiving a complex signal representative of a received symbol from among a plurality of symbols. The received symbol includes a plurality of bits and corresponds to a respective point on a constellation map. Likelihood metrics are generated for the received symbol, with each likelihood metric reflecting a likelihood of the received symbol corresponding to one of the points on the constellation map. The likelihood metrics are arranged in columns and rows. Common likelihood metrics are determined for each column and for each row. The common likelihood metrics are compared to determine a best likelihood metric for the bits in the received symbol that are to be compared by columns, and to be compared by rows.
1. A method for operating a decoder comprising:
receiving a complex signal representative of a received symbol from among a plurality of symbols, with the received symbol comprising a plurality of bits and corresponding to a respective point on a constellation map;
generating for the received symbol a plurality of likelihood metrics, with each likelihood metric reflecting a likelihood of the received symbol corresponding to one of the points on the constellation map, and with the plurality of likelihood metrics being arranged in columns and rows;
determining common likelihood metrics for each column and for each row;
determining which bits in the received symbol are to be compared by columns for selecting best likelihood metrics, and which bits in the received symbol are to be compared by rows for selecting best likelihood metrics;
comparing the common likelihood metrics to determine a best likelihood metric for the bits in the received symbol that are to be compared by columns; and
comparing the common likelihood metrics to determine a best likelihood metric for the bits in the received symbol that are to be compared by rows.
2. The method according to claim 1 wherein determining which bits in the received symbol are to be compared by columns and by rows is based on half of the bits being compared by columns and with the other half of the bits being compared by rows, with the columns and rows matching up with the columns and rows of the plurality of likelihood metrics.
3. The method according to claim 2 wherein for each bit being compared by columns, half of the columns correspond to the bit being a 1 and with the other half of the columns corresponding to the bit being a 0; and wherein for each bit being compared by rows, half of the rows correspond to the bit being a 1 and with the other half of the rows corresponding to the bit being a 0.
4. The method according to claim 3 wherein comparing the common likelihood metrics comprises for each bit to be compared by columns comprises:
comparing the common likelihood metrics for the columns corresponding to the bit being a 1 to determine a best likelihood metric; and
comparing the common likelihood metrics for the columns corresponding to the bit being a 0 to determine a best likelihood metric.
5. The method according to claim 3 wherein comparing the common likelihood metrics comprises for each bit to be compared by rows comprises:
comparing the common likelihood metrics for the rows corresponding to the bit being a 1 to determine a best likelihood metric; and
comparing the common likelihood metrics for the rows corresponding to the bit being a 0 to determine a best likelihood metric.
6. The method according to claim 1 further comprising storing the common likelihood metrics.
7. The method according to claim 1 wherein the decoder is configured as a maximum likelihood decoder.
8. The method according to claim 1 wherein generating the plurality of likelihood metrics for the received symbol comprises calculating a complex distance between the received signal and each symbol in the constellation map.
9. A method for operating a decoder comprising:
receiving a signal representative of a received symbol from among a plurality of symbols, with the received symbol comprising a plurality of bits and corresponding to a respective point on a constellation map;
generating for the received symbol a plurality of likelihood metrics, with each likelihood metric reflecting a likelihood of the received symbol corresponding to one of the points on the constellation map, and with the plurality of likelihood metrics being arranged in columns and rows;
determining common likelihood metrics for each column and for each row;
determining which bits in the received symbol are to be compared by columns for selecting best likelihood metrics, and which bits in the received symbol are to be compared by rows for selecting best likelihood metrics, with the determining comprising
for each bit being compared by columns, half of the columns correspond to the bit being a 1 and with the other half of the columns corresponding to the bit being a 0, and
for each bit being compared by rows, half of the rows correspond to the bit being a 1 and with the other half of the rows corresponding to the bit being a 0;
comparing the common likelihood metrics to determine a best likelihood metric for the bits corresponding to a 1 and corresponding to a 0 in the received symbol that are to be compared by columns; and
comparing the common likelihood metrics to determine a best likelihood metric for the bits corresponding to a 1 and corresponding to a 0 in the received symbol that are to be compared by rows.
10. The method according to claim 9 further comprising storing the common likelihood metrics.
11. The method according to claim 9 wherein the decoder is configured as a maximum likelihood decoder.
12. The method according to claim 9 wherein generating the plurality of likelihood metrics for the received symbol comprises calculating a complex distance between the received signal and each symbol in the constellation map.
13. An electronic device comprising:
a decoder configured to receive a complex signal representative of a received symbol from among a plurality of symbols, with the received symbol comprising a plurality of bits and corresponding to a respective point on a constellation map,
said decoder comprising
a likelihood metrics generation unit configured to generate for the received symbol a plurality of likelihood metrics, with each likelihood metric reflecting a likelihood of the received symbol corresponding to one of the points on the constellation map, and with the plurality of likelihood metrics being arranged in columns and rows,
a common likelihood metrics unit configured to determine common likelihood metrics for each column and for each row, and
a column/row determination unit configured to determine which bits in the received symbol are to be compared by columns for selecting best likelihood metrics, and which bits in the received symbol are to be compared by rows for selecting best likelihood metrics,
a comparison unit configured to
compare the common likelihood metrics to determine a best likelihood metric for the bits in the received symbol that are to be compared by columns, and
compare the common likelihood metrics to determine a best likelihood metric for the bits in the received symbol that are to be compared by rows.
14. The electronic device according to claim 13 wherein said column/row determination unit is configured to determine which bits in the received symbol are to be compared by columns and by rows is based on half of the bits being compared by columns and with the other half of the bits being compared by rows, with the columns and rows matching up with the columns and rows of the plurality of likelihood metrics.
15. The electronic device according to claim 14 wherein for each bit being compared by columns, half of the columns correspond to the bit being a 1 and with the other half of the columns corresponding to the bit being a 0; and wherein for each bit being compared by rows, half of the rows correspond to the bit being a 1 and with the other half of the rows corresponding to the bit being a 0.
16. The electronic device according to claim 15 wherein said comparison unit is configured to perform the following:
compare the common likelihood metrics for the columns corresponding to the bit being a 1 to determine a best likelihood metric; and
compare the common likelihood metrics for the columns corresponding to the bit being a 0 to determine a best likelihood metric.
17. The electronic device according to claim 15 wherein said comparison unit is configured to perform the following:
compare the common likelihood metrics for the rows corresponding to the bit being a 1 to determine a best likelihood metric; and
compare the common likelihood metrics for the rows corresponding to the bit being a 0 to determine a best likelihood metric.
18. The electronic device according to claim 13 wherein said decoder is configured as a maximum likelihood decoder.
19. The electronic device according to claim 13 wherein said decoder comprises a processor and a memory coupled thereto.
20. The electronic device according to claim 13 wherein said common likelihood metrics unit is configured to calculate a complex distance between the received signal and each symbol in the constellation map to generate the plurality of likelihood metrics for the received symbol.