A computationally efficient multipath channel simulator for the COST 207 models

The COST 207 model, used for simulating GSM systems, describes a set of channel taps with specified frequency distributions. This paper describes the performance of various approximations to these distributions using a technique of filtering a noise source. The chip rate channel simulation system incorporates the baseband pulse shaping, achieved through addition of baseband pulse samples, appropriately delayed by the channel model, and sampled at the chip rate. The symbol rate channel simulation system incorporates the baseband pulse shaping in a similar manner, using the cross-correlation properties of the transmitted spread-spectrum code and the despreading code at the receiver. A system is described that uses a filter sampled at a lower rate than the channel sample rate, obviating the need to design filters to operate at very high frequencies. The work is based on a code division multiple access (CDMA) system where the chip rate is high, and the symbol rate low. However, the work may be extended to the simulation of other systems, operating at both high and low bit rates, by combination of appropriate sections of the model described