System Modeling And Performance Analysis Of The Power Saving Strategy With Sleep/Wakeup In WSN

Wireless Sensor Network (WSN) is an energy-constrained network, IEEE 802.15.4 with its low-rate, low-cost and low-power is recognized as an ideal standard for the WSN. Generally, sensor nodes are very small and use battery supply power, so the energy saving is one of the critical issues in WSN. Based on the communication process of sensor nodes in WSN, the periodical sleep/wakeup protocol of IEEE 802.15.4 is modeled and analyzed in this paper.Firstly, based on the IEEE 802.15.4 standard, let sensor nodes keep cyclical sleep/wakeup protocol, considering the setup procedure of the power amplifier from the sleep mode to the active mode to requiring some energy and also causing an additional system delay, the setup procedure is abstracted as setup period. The sleep mode of the sleep/wakeup protocol is considered as vacation period. Some discrete-time queueing models with setup period and vacation period are built.Secondly, due to the single-hop communication process of sensor nodes in WSN, taking into account the memoryless property and the bursty property of the arrival process, the memoryless property and the generality of the transmission process, Geo/Geo/1, Geom/G/1 and Geomξ/G/1 queueing models with setup and vacation period are respectively built. The formulas for some performance measures in terms of the handover ratio, the average latency of data frames and the energy consumption are given. By numerical results and simulations, we demonstrate the in?uence of the constellation size on the system performance under some condition.Thirdly, based on the clustering algorithm, considering an inter-cluster multi-hop transmission network which the sensor nodes are deployed with equidistant spacing in the ideal case, a tandem queueing model with setup and vacation period is built. The formulas of the performance measures are presented. Correspondingly, the dependency relationships of system performance measures on the number of multi-hop are investigated by numerical results and simulations.Finally, based on the single-hop communication process of sensor nodes, considering the tradeoff between the average response time and the power consumption, a cost function is constructed to give the optimal value of the constellation size. For the inter-cluster multi-hop transmission network in WSN, considering the tradeoff among the performance measures, a cost model is developed to give the optimal the number of multi-hop.