Joint Decoding: A Strategy to Mitigate Error Propagation Problem in a Multi-way Relay Channel

Shama Islam (ANU)

APPLIED SIGNAL PROCESSING SERIES

DATE: 2012-09-06
TIME: 10:00:00 - 11:00:00
LOCATION: RSISE Seminar Room, ground floor, building 115, cnr. North and Daley Roads, ANU
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ABSTRACT:
Multi-way relay is a special class of relay systems where multiple users exchange information through a single relay terminal. Here, the relay decodes functions of message pairs, which are simple XOR operations, using time-division multiple-access. The users perform sequential decoding after receiving the messages from relay. Thus, decision about a useras message depends on previous decisions, which results into error propagation problem. To minimize the impact of error propagation, the correlation between adjacent network coded symbols needs to be taken into account. In this talk, a joint decoding mechanism of the network coded symbols in a multi-way relay, based on belief propagation algorithm, will be proposed. The simulation results show that in case of increasing degree of symbol and phase asynchrony, disjoint decoding proposed in previous works, exhibits poorer error performance, whereas joint decoding helps to maintain the performance level close to that in the synchronous case both in additive white Gaussian noise and fading channels. Thus, the new method adds robustness to the multi-way relay channel against channel imperfections like asynchronism and fading in practical propagation environments.
BIO:
Shama is a PhD student in the ASP group.