Performance Evaluation of Best-Path Selection in a Multihop Decode-and-Forward Cooperative System

Multihop communication is considered to be a useful approach for improving the coverage area with reduced transmit power. In this paper, we consider a path-selection-based multihop decode-and-forward (DF) cooperative system. A simple parallel multihop path-based cooperative communication system is considered. It is assumed that all hops in all cooperative paths are subject to independent Rayleigh fading. The best path, that is, the best multihop link between the source and the destination, is selected based on the max-min selection criterion. The relays in the selected cooperative path use the symbol-wise DF protocol, in which they demodulate the received data from the preceding node in a symbol-wise manner and forward it to the succeeding node. An analytical framework is developed for finding an accurate (almost close to exact) error performance of the considered system. To be more specific, we derive an accurate expression of the average bit error rate of the max-min-criterion-based best-path selection scheme, in terms of convergent power series. The coding gain and the diversity order of the scheme are also analytically obtained.