Random-based fair allocation algorithm with fuzzy comprehensive evaluation for single carrier multi-relay cooperative networks

In this paper, we investigate a novel random selection strategy for dual-hop Single-Carrier Frequency-Domain Equalization (SC-FDE) in cooperative systems with multiple relays and amplify-and-forward relaying employing fuzzy comprehensive evaluation-based algorithm. We address the problem of optimal resource allocation for SC-FDE minimum mean square error (MMSE) receivers. In particular, the relays cooperate according to contribution factors which are the result of the fuzzy comprehensive evaluation algorithm. The fuzzy algorithm takes into consideration different fuzzy factors, namely, norm-based selection ratio (NBSR), instantaneous capacity-based selection ratio (CBSR), singular value based selection ratio (SVSR), and equalizer output signal quality-based selection ratio (EQSR) strategies, which are motivated by minimizing the instantaneous error rate. Different sub-channels are further associated with uniform random distribution where the thresholds of the uniform random variables are associated with the contribution factors (evaluated through the fuzzy algorithm). Our novel Random fair allocation fuzzy comprehensive evaluation-based (RFCE) strategy proves superior SER performance as well as improved diversity gain which is achieved by randomizing the allocation. The employed fuzzy algorithm further improves the performance by assigning partial weights to different participating fuzzy factors.