Multihop Diversity - A Precious Source of Fading Mitigation in Multihop Wireless Networks

The concept of multihop diversity is proposed, where all the nodes of a multihop link are assumed to have buffers for temporarily storing their received packets. During each time-slot, the best hop having, for example, the highest signal-to-noise ratio (SNR), is selected from the set of those hops, where the corresponding nodes have packets awaiting transmission in their buffer. The packet is then transmitted over the best hop. Explicitly, this hop-selection procedure yields selection diversity. In this paper, we assume having perfect channel knowledge and focus our attention on the principles and performance bounds of the error probability and outage probability, when M-ary quadrature amplitude modulation (MQAM) is employed. The error probability and outage probability of the multihop links operated under our proposed multihop diversity scheme are investigated, when communicating over Rayleigh fading channels. Our studies show that relying on multiple hops has the potential of providing a significant diversity gain, which may be exploited for enhancing the reliability of wireless multihop communications.