Performance Analysis of IEEE 802.11G Signals Under Different Operational Environments

摘要

A modern military environment requires flexible, capable and robust communications systems. Wireless communications infrastructures can provide all these services that are absolutely necessary to the soldiers on the battlefield or to the mission planners. The IEEE 802.11g wireless LAN seems to fit the military needs since it can provide data rates up to 54 Mbps and it is backward compatible with the earlier 802.11b specification. The purpose of this thesis was to implement, analyze and evaluate the performance of an outdoor point-to- point 802.11g WLAN under different operational environments. The implementation was achieved using two low-cost commercially available wireless bridges and directional external antennas from a well-known manufacturer, Cisco. As part of the analysis, the effective throughput of this standard, the packet error rate and the received signal strength were measured in each of the following three environments: suburban area, medium density vegetation, and coastal. The signal path loss was then calculated from the recorded results and was compared to theoretical results from common outdoor propagation models. A new path loss exponent, n, was also estimated for each case. Based on this exponent, the free space path loss model was properly modified in order to fit the measured path loss results.