Wireless Sensor Networks, Energy Efficiency And Quality Of Service Issues

With the rapid development of embeded system, wireless communication, computer netwok and MEMS, WSN is composed of sensors with the capacity of sensor, computation and wireless network transmission, which is payed broadly attention. In this paper, we focus on the key problem of military battlefield application of WSN. At first, we rearch energy-efficient routing protocols and MAC protocols in military applicaion. Then, we simulateand analyze the network lifetime in heterogeneous wireless sensor networks.At last, we improve QoS problem in WSN.First, we analyze energy-efficient routing protocols in wireless sensor networks. Especially, we simulate the performance of DD routing protocol including average packet delay and energy-efficient according to application of information collection in military battlefield.We propose the formulation of optimal clustering head and maximum network lifetime in multi-level heterogeneous wireless sensor networks. We study their estimated number of round based on a clustering mechanism with varying parameters including size of the sensing field, distance between sensing field and the base station, compress ratio in multi-level heterogeneous network.With energy-efficient MAC protocols, we analysze the performance of IEEE 802.15.4 including average packet delay, channel utility and energy-efficient based on military applicaiton of WSN. It is important that the end-to-end network performance is simulated with beacon-eabled model in this paper.Next, we propose a new method of single-constrained QoS metrics in ad hoc network. This paper combines simulation and theoretic analysis. We study the pertinence of three key QoS metrics including traffic bandwidth, average packet delay and delay jitter. The function formualtion of relationship with QoS metrics is obtained.At last, we study in-depth QoS problem of IEEE 802.15.4 in WSN. We can obtain beacon order impact on packet delay with the certain beacon order by our simulation. The problem of multi-constrained QoS metrics is single-constrained by fitting method, which is the same as QoS problem in ad hoc network.