Experimental Analysis of Cross-Layer Optimization for Distributed Wireless Body-to-Body Networks

We investigate the performance of cross-layer optimized routing across distributed wireless body-to-body networks (BBNs), based on real-life experimental measurements. Two types of dynamic routing are analyzed: shortest path routing (SPR), and cooperative multi-path routing (CMR) associated with selection combining. An open-access experimental dataset incorporating 'everyday' mixed-activities is used for analyzing and comparing the cross-layer optimized routing protocols with different wireless sensor network protocols, i.e., ORPL and LOADng, and also with a standard star topology routing within a BBN (multiple, connected, body area networks). Negligible packet error rate is achieved by applying CMR and SPR techniques with reasonably sensitive receivers. Moreover, at 10% outage probability, CMR gains up to 12, 8, 7, and 6 dB improvements over star topology routing, ORPL, SPR, and LOADng, respectively. We show that CMR achieves the highest throughput (packets/s) while providing acceptable end-to-end delay with 95 ms maximum, at -100 dBm receive sensitivity. The use of an alternate path in CMR reduces retransmissions and increases the packet success rate, which significantly reduces the end-to-end delay and energy consumption for CMR with respect to the other protocols. It is also shown that the combined channel gains across SPR and CMR are gamma and Rician distributed, respectively.