Analysis Of The Performance Of CSMA/CA For IEEE 802.15.4 Networks

Wireless sensor network is a special Ad-hoc network which has the characteristics of rapid deployment and strong anti-destruction. The described features above ensure a wide range of applications for sensor networks such as: military, environment, health, industry control and so on. Recent advances in wireless communication, mirco-eletromechanical systems(MEMS) technology, integrated circuit have enabled the development of low-cost, low-power, multi-functional sensor nodes that are small in size and communicated in short distances. The maturity in technique and potentiality of application needs to be paid more attention.In wireless sensor network, Medium Access Control (MAC) protocol decides the use of wireless channel and the distribution of limited resources between the sensor nodes in wireless communications. It is also used to build the network substructure. Therefore, its performance affects the throughput, delay and other key factors directly. Thus, the performance evaluation of MAC protocol is becoming the domestic and international research hot in wireless network.With the characteristics of low rate, low power and short distance, IEEE802.15.4 is becoming a new communicative standard that is suitable for wireless sensor network. The devices in wireless networks adopt CSMA/CA mechanism to access the channel. However, presently analysis of performance for IEEE 802.15.4 exist some disadvantages. In this paper, IEEE 802.15.4 standard theoretical system has been introduced. Especially, the characteristics of MAC layer have been introduced. Then, a new analytical Markov model to evaluate the throughput of IEEE 802.15.4 is proposed. Adopting the M/G/1/K queuing system makes the model more accurate. At last, The NS-2 simulation has been introduced and has been used for the IEEE 802.15.4 network simulation, which shows that there is a good match between the analytical approximations and the simulation results.