Investigating the impact of inter-user interference in wireless body sensor networks: An experimental approach

Inter-user interference degrades the reliability of data delivery in Wireless Body Sensor Networks (WBSNs) in dense deployments when multiple users wearing WBSNs are in close proximity to one another. The impact of such interference in realistic WBSN systems is significant but has not been well explored. To this end, we investigate and analyze the impact of inter-user interference in practical WBSN systems based on TelosB platform. We capture packet delivery ratio (PDR) and throughput considering unslotted carrier sense multiple access with collision avoidance (unslotted CSMA/CA) and slotted CSMA/CA modes in IEEE 802.15.4 MAC. Our experimental results show that the unslotted CSMA/CA is only effective in light inter-user interference scenarios. Comparably, the slotted CSMA/CA can provide dramatic performance improvement (2.7 times higher in PDR and 1.7 times higher in throughput on average), when severe inter-user interference occurs in WBSN deployment.