Outage Probabilities of Orthogonal Multiple-Access Relaying Techniques With Imperfect Source-Relay Links

An outage probability that is independent of signaling schemes is theoretically derived in this paper for an orthogonal multiple-access relay channel (MARC) system, where the estimates of the information sequences sent from source nodes, regardless of whether or not they are correctly decoded at the relay, are exclusive-OR (XOR)-network-coded and forwarded by the relay to the destination. The MARC system described above is referred to as estimates-exploiting MARC (e-MARC) in this paper for convenience. Following the probability derivation of e-MARC, comparisons are then made with the outage probability of the orthogonal MARC with the Select Decode-and-Forward relaying strategy (MARC-SDF). It is found through simulations that when one of the source nodes is far away from both the relay and the destination, the e-MARC system is superior to MARC-SDF in terms of outage performance. We further numerically calculate the outage probabilities for two special cases, and compare them with the probability of e-MARC. Furthermore, the impact of the source correlation on the outage probability of the e-MARC system is also investigated.