Switching decisions for diversity antennas using autoregressive techniques

Decision-making on switching for diversity antennas has been given considerable attention in recent times in mobile radio communications. Due to multipath propagation of radio waves the signals undergo a phenomenon known as fading and there will be considerable reduction in the average signal strength. By having multiple antennas in the receiver or transmitter the signal strength can be improved by switching back and forth to the antenna that has the maximum signal strength. In this thesis we have used linear prediction method for making decisions on which antenna gives the maximum signal strength. Linear prediction is applied on a single channel system and then is applied on diversity systems where the antennas are placed along the line of motion. It is applied on simulated signals as well as experimentally measured signals, which includes both Line of Sight and non-Line of Sight signals. This thesis gives the mathematical analysis used for linear prediction and the experimental results on simulated and measured data and how diversity systems can be used to solve small-scale fading. The results show that there is considerable improvement in signal strength by using diversity techniques solving much of the problems related to small-scale fading.