Minimizing latency of periodic monitoring traffic in smart body area networks (SmartBANs)

The Smart Body Area Network (SmartBAN) has been proposed to support low power and low latency wireless body area networks. A SmartBAN is organized in a star topology with one hub and a group of sensor nodes. In addition to propagation delay, the uplink transmission latency of a SmartBAN is also dependent on how long a data packet generated at a sensor node has to wait prior to uplink transmission. This delay, which is termed uplink delay, is the focus of this paper. Specifically, we discuss the impact of SmartBAN protocol parameters on the uplink delay of periodic monitoring traffic; traffic which is characteristic of on-body monitoring. We derive a closed-form analytical uplink delay model for periodic traffic, and through this model, provide an understanding on how each SmartBAN timing parameter impacts uplink delay. Using this model, we minimize the uplink delay by choosing an optimal inter-beacon interval to best suit all sensor nodes when sensor data generation periods are known. In the case where the inter-beacon interval is fixed, sensor data generation periods are optimized to minimize uplink delay.