Indoor and outdoor UHF measurements with a 90 MHz bandwidth

The mobile radio channel suffers from multipath propagation which causes frequency selective fading and intersymbol interference. The time variability of the channel results in time fading. These effects limit the coherent bandwidth of the channel and hence limit the bit rate in wideband digital systems. The extent of multipath propagation depends on the type of cell and the environment. Generally, the extent of multipath delays of outdoor environments can be a few tens of microseconds; whereas in indoor environments it is of the order of a few hundred nanoseconds. In addition, in outdoor propagation, the multipath components can be adequately resolved with a 10-40 MHz bandwidth whereas for indoor propagation, the resolution of multipath requires a 90-100 MHz bandwidth. To determine the characteristics of both indoor and outdoor environments a fully programmable wideband chirp sounder capable of generating chirp signals with different bandwidths and with different chirp durations was designed and constructed at UMIST. The sounder was used in both indoor and outdoor measurements. The outdoor measurements were initially carried out with bandwidths from 10-90 MHz. Comparison of the different channel parameters obtained with the different bandwidths demonstrated the resolution and accuracy advantages of sounding with the wider bandwidth. Preliminary results of the time domain descriptors of the channel which include average power delay profiles, delay spread and average delay are presented. The indoor and outdoor measurement results are given for a 90 MHz bandwidth