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PERFORMANCE ANALYSIS OF THE SLEEP/WAKEUP PROTOCOL IN A WIRELESS SENSOR NETWORK

To conserve the energy of sensor nodes in Wireless Sensor Networks (WSNs), a sleep/wakeup protocol is introduced in IEEE 802.15.4. Performance analyses of such queueing systems have been done during the past years. However, most of these analyses are based on continuous-time models and the switching procedure from the sleep mode to the active mode is neglected in order to simplify the process of analysis. In this paper, we study a one-hop WSN system for digital transmission with a setup to capture the working principle of such a sleep/wakeup protocol as a discrete-time multiple vacation queueing model and also consider the WSN system by taking into account the switching procedure between the sleep mode and the active mode at sensor nodes. We present a new effective analysis method to give the formulas for performance measures in terms of the handover ratio, the average latency of data frames and the average energy consump- tion of the sensor node. We also present numerical results to discuss the relationship between the system performance and the modulation constellation size. In addition, we construct a cost function to give the optimal values of the modulation constellation size for minimizing the energy consumption of the sensor node. Keywords: Wireless sensor network, IEEE 802.15.4, Sleep/wakeup, Performance mea- sures, Modulation constellation size, Queueing model, Setup