Collaborative Link-Aware Protocols for Energy-Efficient and QoS Wireless Body Area Networks Using Integrated Sensors

Integrated sensor systems are the promising solutions to the multiprobe design of biomedical sensors for energy efficient wireless body area networks (WBANs). To improve energy efficiency and communication quality-ofservice (QoS) of integrated sensor hubs, a cross-layered energyaware resource allocation (CLEAR) is proposed to exploit the characteristics of medium access control (MAC) and physical (PHY) layers of WBANs. The proposed MAC protocol applies a twin-token bucket model and real-time scheduling to the active superframe interleaving and beacon shifting techniques defined in the IEEE 802.15.6 standard. In addition, the proposed period transformation controlling task end-to-end delay improves the QoS while reducing packet collisions. The proposed PHY protocol is a hybrid of the transmit power control (TPC) and link adaption (LA) strategies, which coordinates the receiver and transmitter with link parameters including data rate, bit error ratio, receiver sensitivity, transmission power, modulation, etc. It adapts the link quality due to human postures or movements to meet the required QoS while minimizing the energy consumption of the transceiver front-end. Experimental results show that CLEAR outperforms existing methods in terms of packet delivery ratio, delay, bandwidth utilization, and energy consumption. In particular, CLEAR reduces average end-to-end delay by 21% as compared to existing methods, and saves an average of 18% of energy consumption over the TPC and LA-based methods at a power of -25 dBm while achieving a maximum 0.05 packet error ratio.