Channel Coding in Random Access Communication over Compound Channels

TL;DR

This paper studies the limits of random access communication over unknown, time-varying wireless channels, deriving bounds on achievable rates and error probabilities for finite-length codes, especially when decoding a subset of users.

Contribution

It introduces new bounds on rate and error probability for random access over compound channels without channel state information, considering finite codeword lengths.

Findings

Derived achievable rate and error probability bounds.

Extended results to decoding subsets of users.

Analyzed finite-length code performance in unknown channels.

Abstract

Due to the short and bursty incoming messages, channel access activities in a wireless random access system are often fractional. The lack of frequent data support consequently makes it difficult for the receiver to estimate and track the time varying channel states with high precision. This paper investigates random multiple access communication over a compound wireless channel where channel realization is known neither at the transmitters nor at the receiver. An achievable rate and error probability tradeoff bound is derived under the non-asymptotic assumption of a finite codeword length. The results are then extended to the random multiple access system where the receiver is only interested in decoding messages from a user subset.