Simulation And Performance Analysis Of IEEE 802.15.4 Network

Wireless personal area network(WPAN) technology aims at short-range wireless communication. Various standards are used in different situations. IEEE 802.15.4 standard is one of them which is a low-rate and low-power WPAN standard and can be applied in the field of interactive toys, industrial automation and commercial application.By analyzing the IEEE 802.15.4 standard, it is found that CSMA/CA and hidden/exposed terminal problems effect the performance of IEEE 802.15.4. Of the many parameters concerning with performance study, Packet delivery ratio, one hop delay and packet collision parameters are adopted here. Besides simulation, mathematical models are used to analyze back-off time and average transmission time.According to the IEEE 802.15.4 standard, the implement of IEEE 802.15.4 model in NS2 is discussed in the aspects of physical layer, media access layer, network device and simulation models in wireless communication. And suggestions are given that GTS part should be added to the model.Specific models are chosen according to our research. Two ray ground model is used as propagation model and the GE error model is used for channels. Device to coordinator transmission, coordinator to device transmission and peer to peer transmission and direct data transmission are used. All nodes send their packets by poisson process.After the simulation scenarios are built and parameters are set three studies are made. The study of hidden/exposed terminal problem in IEEE 802.15.4 network shows that the hidden/exposed terminal problem does not affect a lot on the performance of a IEEE 802.15.4 network running in a low rate. The study of the effect of beacon mode on network performance shows that with a star topology network performance is not affected by beacon and non-beacon mode. The study effect of ack frame on network performance shows that in star-net with a low rate the performance is not affected by the ack mechanism.