Adaptive detection for asynchronous uplink IDMA shallow-water acoustic channels

S. N. Qader, C. C. Tsimenidis, B. S. Sharif, M. Johnston

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


In this paper, a novel adaptive detector for uplink interleaved division multiple access (IDMA) transmissions is proposed. The conventional IDMA receiver mitigates multiple access interference (MAI) and inter-symbol interference (ISI) by exchanging iteratively extrinsic soft log-likelihood ratio (LLR) information between the Elementary Signal Estimation (ESE) and the a posteriori probability decoder (APP-DEC). In contrast, the proposed receiver jointly removes MAI and ISI effects by utilizing an adaptive, chip-level, centralized decision feedback equalizer (CDFE). The CDFE equalizer iteratively exchanges data symbols with the DEC. In decision-directed mode, for efficient estimation of the transmitted symbols, the CDFE equalizer depends on both a priori information of the user's information symbols, which are fed back from the decoders, and the estimated channel impulse response. Simulation results using experimentally obtained shallow water impulse responses demonstrate the superior performance of the proposed CDFE receiver over the decentralized decision feedback equalizer (DDFE) and linear equalizer (LE).

Original languageBritish English
Title of host publicationSensor Signal Processing for Defence, SSPD 2012
StatePublished - 2012
EventSensor Signal Processing for Defence, SSPD 2012 - London, United Kingdom
Duration: 25 Sep 201227 Sep 2012

Publication series

NameIET Seminar Digest


ConferenceSensor Signal Processing for Defence, SSPD 2012
Country/TerritoryUnited Kingdom


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