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Coding Schemes for Discrete Memoryless Multicast Networks with Rate-limited Feedback

Research paper by Youlong Wu

Indexed on: 16 Jul '15Published on: 16 Jul '15Published in: Computer Science - Information Theory



Abstract

Coding schemes for discrete memoryless multicast networks with rate-limited feedback from the receivers and relays to the transmitter are proposed. The coding schemes are based on block-Markov coding, {joint backward decoding} and hybrid relaying strategy. In each block, the receivers and relays compress their channel outputs and send the compression indices to the transmitter through the feedback links. In the next block, after obtaining the compression indices, the transmitter sends them together with the source message. Each receiver uses backward decoding to jointly decode the source message and all compression indices. Our coding schemes generalize Gabbai and Bross's results for the single relay channel with partial feedback, where they proposed coding schemes based on restricted decoding and deterministic partitioning. It is shown that for the single relay channel with relay-transmitter feedback, our coding schemes can strictly improve on noisy network coding, distributed decode-forward coding and all known lower bounds on the achievable rate in the absence of feedback. Furthermore, motivated by the feedback coding schemes, we propose a new coding scheme for discrete memoryless multicast networks without feedback, which also improves noisy network coding and distributed decode-forward coding.