Oblivious cooperative transmission with multi-layer codes

We consider a wireless network in which a source terminal communicates with a destination and a relay terminal is occasionally present in close proximity to the source without source\´s awareness, suggesting oblivious protocols. We incorporate a two-layer broadcast approach into two cooperative strategies based on the decode-and-forward scheme - Sequential Decoded-and Forward (SDF) and the Block-Markov (BM) for which the message transmission is carried out via multiple blocks. The broadcast approach splits the transmitted rate into superimposed layers corresponding to a "bad" and a "good" channel states, allowing better adaptation to the actual channel conditions without any feedback link to the transmitter. Substantial gains in throughput are exhibited for the single user, Multiple-Input-Single-Output (MISO) and the general relay settings using successive decoding technique. For the single layer BM, a conjecture regarding the optimal correlation coefficient between the source and the relay\´s transmission is suggested. For the discrete multi-layer BM scheme involving two or more layers, it is demonstrated that perfect cooperation (2×1 MISO) rates are achievable with small collocation gains.