Channel Uncertainty Effects on Multihop AF and DF Wireless Mobile Networks

The main purpose of this paper is studying both the regenerative decode-and-forward (DF) and nonregenerative amplify-and-forward (AF) schemes for mobile wireless relay network under channel uncertainty. A wireless system consisting of one-source-one-destination mobile pair and N multihop mobile relay nodes is under investigation. The scenario being studied is appropriate for low power or widely spread network of mobile nodes, such as vehiculars, where transmitted signal can reach its first tier nodes only and degrades before reaching its second tier neighbors. Therefore, unlike previous work in the literature, this paper studies a system where no direct link exists between any node and its second tier neighbors. New proposed detection schemes, utilizing the maximum ratio combiner (MRC) principle, are proposed and designed for such a network with uncertain mobile channels. It is applied at both relays and the destination to optimally detect the received signals. Using the new proposed detection scheme, Monte-Carlo simulations are employed, and bit error rate (BER) simulation results are presented to evaluate the system performance under study. Performance comparisons for only source-relay links and for only relay-destination links under channel uncertainties were incorporated as well.