A multilevel soft quantize-and-forward scheme for multiple access relay systems

Dushantha N. K. Jayakody, Jun Li, Bin Chen, Mark F. Flanagan

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

6 Citations (Scopus)


This paper proposes the novel technique of multilevel threshold based soft quantization (MLT-SQ) for a multiple access relay system (MARS). The scheme is suitable for systems using binary phase-shift keying (BPSK) and network coding at the relay. In the proposed MLT-SQ protocol, the relay evaluates the reliabilities, expressed as log-likelihood ratios (LLRs), of the received signals from the two sources. It then computes the LLRs of the network-coded packet and quantizes these using a set of optimized multilevel thresholds, forwarding the resulting “quantized soft symbols” to the destination. We provide the derivation for the bit error rate (BER) at the destination, based on which we optimize the multilevel thresholds to minimize the BER. Compared to competing schemes, the performance of our system is superior in terms of BER when the same amount of channel state information (CSI) is exploited.
Original languageEnglish
Title of host publication25th IEEE Annual Symposium on Personal, Indoor and Mobile Radio Communications Conference, PIMRC 2014
Place of PublicationPiscataway
PublisherInstitute of Electrical and Electronics Engineers
Number of pages5
ISBN (Electronic)978-1-4799-4912-0
ISBN (Print)978-1-4799-4911-3
Publication statusPublished - 2014
Externally publishedYes
Event25th IEEE Annual International Symposium on Personal, Indoor, and Mobile Radio Communication (PIMRC 2014) - Washington, United States
Duration: 2 Sep 20145 Sep 2014
Conference number: 25


Conference25th IEEE Annual International Symposium on Personal, Indoor, and Mobile Radio Communication (PIMRC 2014)
Abbreviated titlePIMRC '14
CountryUnited States
Internet address

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