Co- and adjacent channel interference performance of GSM in Rayleigh fading environment

The GSM recommendations state that reference interference will be achieved at a C/I margin of 9 dB for co-channel interference and that the margin is -9 dB C/I for adjacent channel interference. The results of measurements show that under simulated Rayleigh fading conditions, this is not adequate and a higher margin is needed. Furthermore, the results show that due to the channel coding process and interleaving, the statistical measure of signal quality is dependant on the speed of the mobile. The results also show that the reception quality parameter used in the GSM standard for many of the important decision such as handovers and power control is also dependent on speed and is not an true reflection of the speech quality