Outage performance analysis for buffer-aided relay system over non-identical Rayleigh fading channels

To obtain an insight about the effect of channel parameters on buffer-aided relay selection systems, the max-link selection (MLS) schemes are investigated over independent and non-identically distributed (i.ni.d) Rayleigh fading channels. Specially, by employing Markov chain, the authors first model the state transition matrix and outage probability. Secondly, they obtain the closed-form expressions of the corresponding statistic properties. The presented results show: (i) when the relaying channels are asymmetric (but the source–relay links are independent and identically distributed fading, so does the relay–destination links), the MLS scheme outperforms the traditional best relay selection (T-BRS) and max–max best relay selection (MM-BRS) schemes. However, when the relaying links are unbalanced severely, the MLS scheme does not provide diversity gain over the T-BRS and MM-BRS schemes; and (ii) For the more general i.ni.d fading case, it is observed that the MLS schemes can be inferior to the MM-BRS schemes. The derivations of this work have values for reference. For example, by using the achieved statistic properties they can further perform the investigation on the delay for the buffer-aided MLS relaying systems over i.ni.d fading channels, which is a critical issue of buffer-aided relay selection systems.