Mitigating Interference in Coexisting IEEE 802.15.6 Networks using Superframe Interleaving

Abstract

IEEE 802.15.6 standard is designed for Wireless Body Area Network (WBAN). WBAN connects wireless sensor nodes in/on or around the body. WBAN is specially designed for monitoring e-health applications like temperature, blood pressure and fever etc. One of the basic concerns in IEEE 802.15.6 networks is coexistence of multiple BANs. This is a natural phenomenon because a network is around a single body therefore multiple BANs can be within the radio range of a single BAN. For example, in a sitting room, conference room, stadium and hospital BANs attached with different peoples can be within the radio range of each other. When multiple BANs coexist then the performance of an individual BAN is degraded due to interference with neighboring BANs. Interference decreases successful transmission of data, thus lowering the throughput and the energy of the devices is wasted which is a very precious resource for WBAN devices. This work is amid at studying the coexistence issues within the WBANs. IEEE 802.15.6 proposes different solutions including channel hoping, beacon shifting, and superframe interleaving for solving the issue of coexistence. The complete Superframe interleaving duration is divided in such a way that all neighboring BANs are given separate equal slots within the superframe. The superframe interleaving solution of IEEE 802.15.6 is able to accommodate only two BANs and assigns equal duration to each BAN. Superframe interleaving defined by IEEE 802.15.6 does not take into consideration the traffic load within a single BAN. For example, if there are two BANs each BAN equally share the bandwidth or superframe structure irrespective to the traffic requirements of a single networks. In this study, we have proposed a scheme for solving the coexistence issue by using dynamic active superframe interleaving. The scheme adjusts multiple superframes of interfering BANs according to the traffic load observed in each network. Hence, instead of assigning fix superframe duration to each BAN, duration is assigned according to each network’s traffic requirement. Detailed simulation analysis using OPNET, concludes that proposed scheme provides less interference and higher throughput than simple interleaving used in IEEE 802.15.6.