Cooperative Switched Combining for Wireless Body Area Networks

Characterization of cooperative switched combining (SwC), for the 'everyday' wireless body area network (BAN) wireless channel, is presented. A decode-and-forward protocol is chosen for the on-body cooperative BAN. The outage probability of two and three-branch cooperative coherent SwC, where the three-branch cooperative SwC is implemented as a variant of switch-and-examine combining, is compared with that for cooperative coherent selection combining (SC). Three typical locations for relays/hubs are considered, along with seven typical sensor locations, all on-body. The outage performance of SwC is not considerably degraded when compared to SC, and there is still significant improvement over direct single-link communications. However the benefit of SwC with respect to SC is demonstrated in terms of the switching rate between branches, which for both two and three-branch SwC is considerably smaller, between 12% and 32% of that of SC for any hub and relay/s locations. This may allow for easier implementation in practical IEEE 802.15.6 BAN.