Coding Versus ARQ in Fading Channels: How Reliable Should the PHY Be?

—This paper studies the tradeoff between channel coding and ARQ (automatic repeat request) in Rayleigh blockfading channels. A heavily coded system corresponds to a low transmission rate with few ARQ retransmissions, whereas lighter coding corresponds to a higher transmitted rate but more retransmissions. The optimum error probability, where optimum refers to the operating point that maximizes the average successful throughput, is derived and is shown to be a decreasing function of the average signal-to-noise ratio and of the channel diversity order. A general conclusion of the work is that the optimum error probability is quite large (e.g., 10% or larger) for reasonable channel parameters, and that operating at a very small error probability can lead to a significantly reduced throughput.

• Type: Conference
• Year: 2009
• Where: GLOBECOM
• Authors: Peng Wu, Nihar Jindal
• Keywords: GLOBECOM 2009, Lighter Coding Corresponds, Optimum Error Probability, Small Error Probability, Telecommunications