Signal detection performance in Rayleigh fading environments with a moving antenna

The performances of a single-antenna handheld receiver in detecting a narrowband signal in a Rayleigh fading environment that is temporally static but decorrelates spatially are analysed. Of interest is comparing the detection performance of a static antenna with that of a moving antenna subject to constant processing time. It is shown that the net processing gain resulting from randomly moving the antenna relative to keeping it static can be large, namely over 11 dB in some cases, which is significant for numerous indoor applications. It is further demonstrated that, for a given utilisation scenario, there is an optimum number of spatial samples that maximise the processing gain advantage of the moving antenna. Generally, if the spatial trajectory of the antenna becomes too large, then the loss associated with the signal decorrelation dominates and undermines the gains achieved by the increased spatial diversity. Practical implementation issues including the sensitivity of the proposed method to trajectory estimation are investigated. An extensive set of measurements based on CDMA 2000 signals propagated from outdoor terrestrial base stations and captured in indoor multipath environments using static and moving antennas are utilised to experimentally substantiate these theoretical findings.