Energy-efficient two-hop extension protocol for wireless body area networks

Recent technological advances in integrated circuits, wireless communications and physiological sensing have allowed ultra-low power, intelligent-monitoring tiny devices to settle around the human body, forming a wireless body area network (WBAN) to collect information for a particular purpose. As these tiny devices are low-weighted and energy-restricted, `energy efficiency´ becomes a key issue. Built in 2012 to facilitate the development of WBAN, the `IEEE 802.15.6´ standard operates with one-hop star and two-hop restricted tree topologies. Its two-hop extension protocol has relaying nodes (working as a microhub), process node joining and schedule two-hop transmissions, thus reducing their lifetime. To reduce the energy consumption and overhead for relaying nodes, the authors introduce a new two-hop extension protocol which lets the generally better resource-equipped hub directly transmit packets to the downlink relayed nodes. Analytical and experimental evaluations show that when advancing `IEEE 802.15.6´ in extending the lifetime of relaying nodes with less energy consumption and overhead, the authors´ new protocol also retains its advantages, including longer lifetime for relayed nodes and lower bit error rates.