# US 8,149,959 B1 · Enhancements of soft decoders and detectors on asymmetric channels > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,149,959 B1 - Document ID: US8149959B1 - Status: Granted - Kind: B1 - Application number: 13/012,407 - Filed: 2011-01-24 - Granted: 2012-04-03 - Earliest claimed: 2006-08-24 - Assignees: Marvell International Ltd. - Inventors: Nedeljko Varnica; Seo-How Low; Gregory Burd; Zining Wu - Web page: https://patentgrep.com/patent/US8149959B1 ## CPC - H04L 1/0054: {Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Systems and methods for enhancing soft decoders and detectors on asymmetric channels are provided. The methods include acquiring log-likelihood ratios (LLRS) for error-correction code (ECC) encoded data symbols, selecting a quality measure function and a quality threshold based on the LLRs, applying the selected quality measure function to the LLRs to obtain quality measures, comparing the quality measures to the selected quality threshold, and updating the LLRs for selected ECC encoded data symbols based on the comparisons. The updating may occur by multiplying the LLRs for the selected ECC encoded data symbols by a selected scaling factor. ## Claims ### Claim 1 A method for soft decoding data, the method comprising: acquiring from a channel by a demodulator soft information for a plurality of error-correction code (ECC) encoded data symbols; selecting by a channel detector/decoder pair a quality measure function and a quality threshold based, at least in part, on the soft information; applying the selected quality measure function to the soft information to obtain quality measures; comparing the quality measures to the selected quality threshold; and updating the soft information for selected ECC encoded data symbols based on the comparisons. ### Claim 2 (depends on 1) The method of claim 1, wherein the ECC encoded data symbols are represented in binary, and wherein selecting the quality threshold further comprises: determining a first portion of the soft information corresponding to data symbol ‘0’; determining a second portion of the soft information corresponding to data symbol ‘1’; and selecting the quality threshold based, at least in part, on a distribution of the soft information in the first and second portions. ### Claim 3 (depends on 1) The method of claim 1, wherein the ECC encoded data symbols are represented in binary, and wherein selecting the quality threshold further comprises: determining a first portion of the soft information corresponding to data symbol ‘0’; determining a second portion of the soft information corresponding to data symbol ‘1’; determining a first proportion based on the soft information in the first portion that is positive; determining a second proportion based on the soft information in the second portion that is negative; and selecting the quality threshold based, at least in part, on comparing the first and second proportions. ### Claim 4 (depends on 1) The method of claim 1, wherein the selected quality threshold is negative and comparing the quality measures to the selected quality threshold further comprises determining whether the quality measures are less than the selected quality threshold. ### Claim 5 (depends on 1) The method of claim 1, wherein the selected quality measure is positive and comparing the quality measures to the selected quality threshold further comprises determining whether the quality measures are greater than the selected quality threshold. ### Claim 6 (depends on 1) The method of claim 1, further comprising: decoding the ECC encoded data symbols based, at least in part, on the updated soft information; and outputting decoded data symbols. ### Claim 7 (depends on 1) The method of claim 1, wherein the selected quality threshold is positive, and updating the soft information for selected ECC encoded data symbols further comprises applying a modification function to the soft information which are greater than a scaling factor. ### Claim 8 (depends on 7) The method of claim 7, wherein the modification function comprises multiplying the soft information by the scaling factor, wherein the scaling factor is greater than one. ### Claim 9 (depends on 1) The method of claim 1, wherein the selected quality threshold is negative, and updating the soft information for selected ECC encoded data symbols further comprises applying a modification function to the soft information which are less than a scaling factor. ### Claim 10 (depends on 9) The method of claim 9, wherein the modification function comprises multiplying the soft information by the scaling factor, wherein the scaling factor is greater than one. ### Claim 11 A system for soft decoding data, the system comprising: an encoder to encode a plurality of error-correction code (ECC) encoded data symbols; a digital modulator to transmit the ECC encoded data symbols over a channel; a demodulator to receive the plurality of ECC encoded data symbols and acquiring soft information for the plurality of ECC encoded data symbols; and a channel detector/decoder pair configured to: select a quality measure function and a quality threshold based, at least in part, on the soft information; apply the selected quality measure function to the soft information to obtain quality measures; compare the quality measures to the selected quality threshold; and update the soft information for selected ECC encoded data symbols based on the comparisons. ### Claim 12 (depends on 11) The system of claim 11, wherein the ECC encoded data symbols are represented in binary, and the channel detector/decoder pair is further configured to: determine a first portion of the soft information corresponding to data symbol ‘0’; determine a second portion of the soft information corresponding to data symbol ‘1’; and select the quality threshold based, at least in part, on a distribution of the soft information in the first and second portions. ### Claim 13 (depends on 11) The system of claim 11, wherein the ECC encoded data symbols are represented in binary, and the channel detector/decoder pair is further configured to: determine a first portion of the soft information corresponding to data symbol ‘0’; determine a second portion of the soft information corresponding to data symbol ‘1’; determine a first proportion based on the soft information in the first portion that is positive; determine a second proportion based on the soft information in the second portion that is negative; and select the quality threshold based, at least in part, on comparing the first and second proportions. ### Claim 14 (depends on 11) The system of claim 11, wherein the selected quality threshold is negative and the channel detector/decoder pair is further configured to compare the quality measures to the selected quality threshold further by determining whether the quality measures are less than the selected quality threshold. ### Claim 15 (depends on 11) The system of claim 11, wherein the selected quality measure is positive and the channel detector/decoder pair is further configured to compare the quality measures to the selected quality threshold further by determining whether the quality measures are greater than the selected quality threshold. ### Claim 16 (depends on 11) The system of claim 11, wherein the detector/decoder pair is further configured to: decode the ECC encoded data symbols based, at least in part, on the updated soft information; and output decoded data symbols. ### Claim 17 (depends on 11) The system of claim 11, wherein the selected quality threshold is positive, and the channel detector/decoder pair is further configured to update the soft information for selected ECC encoded data symbols by applying a modification function to the soft information which are greater than a scaling factor. ### Claim 18 (depends on 17) The method of claim 17, wherein the modification function comprises multiplying the soft information by the scaling factor, wherein the scaling factor is greater than one. ### Claim 19 (depends on 11) The system of claim 11, wherein the selected quality threshold is negative, and the channel detector/decoder pair is further configured to update the soft information for selected ECC encoded data symbols by applying a modification function to the soft information which are less than a scaling factor. ### Claim 20 (depends on 19) The system of claim 19, wherein the modification function comprises multiplying the soft information by a scaling factor, wherein the scaling factor is greater than one.