A Novel Online Network Coding Scheme for Broadcast Channels with Imperfect Feedback and Decoding Delay Constraints

In a wireless broadcast channel, each packet is typically associated with a decoding delay constraint. Meeting the constraints of packets under the imperfect feedback is a challenging issue for any online network coding scheme. Thus motivated, in this paper, we investigate the throughput performance of the single-hop network with the decoding delay constraints and imperfect feedback, and have proposed an Upper Triangle Network Coding (UTNC) scheme. The proposed scheme has designed an upper triangular generation matrix G, based on which the original packets in the transmission queue are encoded by the sender and broadcast to multiple receivers. We have evaluated the throughput performance of the UTNC scheme with the different decoding delay constraints, feedback erasure probabilities and the number of receivers. Simulation results show that the proposed scheme has effectively accelerated the packet decoding and avoided the meaningless retransmission resulting from the imperfect feedback. More importantly, the UTNC scheme has achieved higher throughput compared with the conventional ARQ for network coding (ANC) scheme.