An empirical comparison of a distributed antenna microcell system versus a single antenna microcell system for indoor spread spectrum communications at 1.8 GHz

摘要

An empirical study of two indoor microcellular structures intended to be used with spread spectrum communications is the focus of this paper. The performance of a distributed antenna system consisting of four corner reflector antennas with each antenna located at a corner of a rectangular cell is compared to that of a single antenna system consisting of a single discone antenna located at the center of the same cell. The four distributed antennas were connected to a 4-way splitter/combiner with different lengths of low loss coaxial cable which introduced 25.6 nanoseconds of differential delay between successive antennas. The differential delay was introduced to provide time diversity which can be optimally combined with a matched filter/RAKE receiver. Measurements were performed in both microcell structures at 1.8 GHz on a single floor of TR Labs research location in Calgary to obtain channel impulse responses and frequency selective fading results using 140 MHz and 50 MHz of bandpass bandwidth, respectively. Frequency selective fading statistics, RMS delay spreads, excess delay spreads and a comparison of the time/space diversity of the antenna systems are documented.