Incremental Cooperative Relaying in Time-Correlated Rayleigh Fading Channels

Incremental relaying is a communication technique enabling cooperative diversity in wireless networks. The relay forwards a correctly decoded packet only after getting the feedback that the destination failed to receive the data directly from the source. We model an incremental relaying protocol as a time-discrete finite-state Markov process and analyze its throughput performance in time-correlated radio channels with Rayleigh fading. We also determine two boundary cases: fully correlated and fully uncorrelated fading channel. The analysis shows that the throughput gains of incremental relaying to conventional Automatic Repeat-reQuest retransmission strongly depend on the channel correlation, relay position, and source-to-destination fading margin.