Adaptive Combining of Signals with Unequal Noise Variances

This paper demonstrates the signal combining by use of adaptive algorithms for wireless communication networks. The adaptive combiner operates under different noise variances on each branch of the multi-antenna receiver. We utilise adaptive signal combining technique with least mean squares (LMS) algorithm based on Newton´s Recursion Method. It is shown that the adaptive combining filter with LMS converges with respect to signal to noise ratio (SNR) and not to the transmit power Simulation results show that the Adaptive Combining technique proposed in this paper provides significant mean square error(MSE) improvement which reflects to BER performance improvement. This improvement is more obvious when two independent signals arrive at the receiver communication terminal (at different antennas) with 10dB of SNR difference, which is a very common situation in wireless communication systems.