Lossy Forwarding Technique for Parallel Multihop-Multirelay Systems

This paper proposes a Partial Hybrid Automatic Repeat reQuest (P-HARQ) scheme where the relaying nodes select either forwarding the erroneous packets or requesting retransmission. In contrast to the conventional technique where the erroneous packets is always discarded, the packets found to have errors after decoding are interleaved, re-encoded, and forwarded if relay selects the forwarding mode. This technique is refer to as lossy forwarding. In this paper, the mode selection (either forwarding or requesting retransmission) is based on the confidence indicator (CI). Since the channels are assumed to suffer from block Rayleigh fading, the CI is calculated via online mutual information measurements, block-by- block. Results of computer simulations conducted to confirm the superiority of the proposed P-HARQ technique in terms of bit-error-rate, packet-error-rate and throughput performances in parallel multihop wireless multirelaying systems, are presented.