B²IRS: A Technique to Reduce BAN-BAN Interferences in Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are particular networks characterized by limited energy and computational resources and, if their transmission range is limited to a person's area, they are known as Body Area Networks (BANs). When two or more BANs are co-located and operate on the same channel, active periods can overlap and transmissions can conflict. This phenomenon, that drastically reduces performances and reliability of BANs, is known as BAN-BAN interference. In order to solve this issue, it is possible to employ techniques such as channel switching. However, channel switching is not suitable if the amount of channels is lower than the amount co-located BANs and, considering that interferences of Zigbee/802.15.4 networks with other technologies like 802.11 or Bluetooth reduce the amount of channels available for communication, an alternative approach is required. This paper introduces a BAN-BAN Interference Reduction System (B
²
IRS) which reschedules beacon packets in order to avoid active period overlap, reducing the interferences between distinct BANs. This approach is complementary to channel switching since it works with single-channel interferences, that arise when no free channels are available anymore. Experimental results, conducted comparing our methodology with the original IEEE 802.15.4, show that B
²
IRS is able to effectively reduce BAN-BAN interference, making it possible to almost maintain the same performance and energy consumption of an ideal situation (without interferences).