Bit-Flipping Helper-Assisted Lossy Communications: Performance Analyses Over Fading Multiple Access Channels

The primary objective of this article is to establish an analytical framework for evaluating the rate-distortion and the outage probability performance in Internet-of-Things (IoT) systems based on lossy cooperative wireless communications. Two correlated sources transmit information through fading multiple access channels (MACs) with the assistance of a bit-flipping (BF) helper. To begin with, we derive a closed-form expression of the inner bound on the achievable rate-distortion region. To reduce computational complexity, we then propose an approximate method for calculating the outage probability based on the lossy source-channel separation theorem. Moreover, Monte-Carlo methods are adopted to evaluate the outage probability in MAC and orthogonal transmission schemes. Theoretically, approximate results are also compared with the exact results obtained by Monte-Carlo methods. It is shown that the gap between the approximate and exact performance curves decreases as the distortion requirement becomes smaller. Especially when the distortion requirement reduces to zero, the approximated outage probability is exactly the same as the results obtained by Monte-Carlo methods. In addition, we also present performance comparisons in terms of the outage probability between Rayleigh and Nakagami-m fading, and between BF helper and optimal helper.