Title :
Analysis of Network Coded HARQ for Multiple Unicast Flows
Author :
Larsson, Peter ; Smida, Besma ; Koike-Akino, Toshiaki ; Tarokh, Vahid
Author_Institution :
Sch. of Electr. Eng., R. Inst. of Technol., Stockholm, Sweden
Abstract :
In this paper, we consider network coded (NCed) Hybrid-ARQ (HARQ) for multiple unicast flows. The main contribution of the paper is the derivation of throughput expressions for NCed HARQ with arbitrary number of users in identical i.i.d. channels amid packets for all users. We apply the result to Rayleigh fading channels and two packet combining schemes: incremental redundancy (IR) and chase combining (CC). We verify the analytical results with simulations and observe substantial SNR improvements over NCed ARQ and HARQ. The SNR gains in the moderate/high and low throughput regimes are mainly due to network coding and packet combining, respectively. For low/moderate SNRs, NCed HARQ with IR surpasses the CC performance. In addition, we introduce a novel re-transmission strategy that makes the network coding more efficient at low SNR.
Keywords :
Rayleigh channels; automatic repeat request; network coding; redundancy; telecommunication network reliability; CC performance; IR; NCed; Rayleigh fading channels; SNR improvements; channels amid packets; chase combining; hybrid-ARQ; identical iid channels; incremental redundancy; low throughput regimes; moderate-high regimes; multiple unicast flows; network coded HARQ; packet combining; retransmission strategy; throughput expression; Automatic repeat request; Decoding; Encoding; Fading; Signal to noise ratio; Throughput; Unicast; Network coding; Rayleigh channels; automatic repeat request (ARQ); cooperative systems;
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2012.121112.110202
