|Second-Order Achievable Rates for a Block Fading Gaussian Multiple Access Channel
|Deekshith P K, Vinod Sharma, Indian Institute of Science, India
|S.12: Second-order Analysis
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|In this work, we consider a Gaussian multiple access channel (GMAC) subject to block fading that is independent across users. We derive inner bounds on the capacity region for a given finite codeword length and non-vanishing average probability of error. We assume perfect channel state information (CSI) at the receiver (CSIR) and no CSI at the transmitters. The bounds are derived subject to a peak power constraint on the transmitted codewords. Our inner bounds are derived using Gaussian codebooks. These bounds characterize deviation from the ergodic capacity region upto second-order. Using numerical examples, we illustrate the back-off from the boundary of the ergodic capacity region.