Wideband channel measurements at 900 MHz

The paper describes RF channel measurements conducted in a mixed urban-suburban region of Bellevue, Washington using a BPSK DS-SS sounder with a bandwidth of 20 MHz (10 Mc/s) operating in the 915 MHz ISM band. The survey was used to study delay spread characteristics in a 1.23 MHz wide channel. The fast-fading envelope distribution of resolvable rays was found to vary between Rayleigh and Rician-distributed at 1.23 MHz bandwidth. At a higher bandwidth of 20 MHz the distribution was approximately Rician with a K-factor of 8-12 dB. It was estimated that a 4-finger, 2-port non-coherent IS-95 base station would make use of the second finger pair approximately 60% of the time. The differential delay between 1st and 2nd finger assignments was usually less than 8 μs, and there was little observable variation in the delay of the first-arriving multipath component between channel soundings spaced at 3 s intervals