Two-hop relay-assisted cooperative communication in wireless body area networks: An empirical study

The pervasive use of wireless body area networks (BANs) has incurred potential inter-BAN interference, which can cause severe performance degradation. In this article, the coexistence of BANs is experimentally performed. A relay-assisted cooperative communications scheme is implemented in a real IEEE 802.15.4-based BAN system with a beacon-enabled mode and guaranteed time slot (GTS) scheduling. As far as we know, it is the first experimental work that enables real-time investigation of the effectiveness of cooperative communications in BANs for co-channel radio interference mitigation. First- and second-order statistics, including outage probability, level crossing rate (LCR), and average fade/nonfade duration, are calculated from the measured effective channel gains of the device-to-coordinator links across all superframes. Empirical results demonstrate significant advantages of using two-hop relay-assisted communications over traditional star topology BAN. Advantages include a maximum of a 10dB increase in channel gain threshold at an outage probability of 10%, which corresponds to a guideline for a 10% maximum packet error rate as specified in the IEEE BAN standard; a reduction in the level crossing rate by a factor of 5 at a channel gain threshold of -100dB; and an average nonfade duration prolonged by a factor of 5 at the same threshold.