Design and implementation of hybrid circuit/packet switching for wearable systems

This paper presents a network router and transceiver for wearable, low-power, high-speed Body Area Networks (BAN) applications running in a mesh network of sensors embedded in textiles and connected to each other with conductive yarns functioning as bidirectional transmission channels. The routing of data packets from sensor nodes to a sink node is based on hybrid circuit and packet switching. In comparison with pure packet switching, hybrid routing decreases end-toend delay, power consumption and buffer size. The proposed design uses independent sender, receiver and circuit switching modules, thereby allowing the nodes to simultaneously send and receive data. The simulation results show that circuit and hybrid switching modes significantly increase the performance of the system. In addition, implementing the complete packet process on FPGA, instead of using an external microcontroller as in previous work, enables a much faster routing process. The results are based on a Verilog description of the system, which has been synthesized for a low-power IGLOO FPGA with Libero Project Manager and simulated with ModelSim. The implementation operates successfully at a data rate of 20 Mbps.