Measurement and characterization of radio channels in fixed wireless access at 2 GHz

by Rockwood, Deborah Mary

Fixed Wireless Access is emerging as an alternative to conventional telephone services in which subscriber loops are based on wired connections. Fixed wireless telephony is ernerging in developing countries as a favoured approach due to its Low installation costs and shon deployment time. In developed countries, it is gaining rnomentum as the technology of choice for new entrants in local phone access markets. In addition ro cost savings. wireless telephony provides the advantage of portabiIiry. However, to compete with wired telephony, Fixed Wireless Access must provide a higher quality of service. To facilitate the installation of subscriber phone stations. avoiding the need for an outside antenna system is highly desirable. An indoor antenna has the advantage of low installation cost and it avoids the need for the mounting structure associated with roof antennas. An outdoor base station transmit antenna and an indoor user receive antenna installation are examined in this thesis. To mitigate multipath fading, space divenity is incorporated. The performance of the outdoor/ indoor link is rneasured and anaIyzed. The rneasurement results are analyzed to determine the envelope fading statistics and diversity performance. The average diversity gain for a 99% availability is 5.1 dB. Significant variations in single channel fade statistics are mitigated by space divenity. Variations in the envelope cross-correlation adversely affect the diversity gain. The outdoor/ indoor communications large-scale fade statistics are a path loss exponent of 1.96 and a shadow margin of 7.33 dB. The path loss exponent is lower than for indoor communications and the shadow margin experiences less obstruction than in the indoor case. The results are useful for predicting communication reliability and quality of service for outdoorl indoor communication in similar buildings.