Performance of Diversity Techniques at Mobile Handset in Fading Channels

Abstract

The demands for greater capacity and lower transmitted power have historically motivated research in spatial diversity systems. Diversity techniques have been implemented in many current systems and have been shown to reduce the transmit power required to maintain acceptable system performance. Traditionally spatial diversity is based on the transmission and reception of a single stream of symbols through independent and spatially separated propagation channels. In more recent developments, new techniques use diversity concepts to resolve multiple independent streams of data and increase the potential data-rate. The effectiveness of these multi-element arrays in communication systems has been found to depend on antenna design and specific characteristics of the propagation channels. In this thesis, we derive bit error performance bounds for various statistical and spatial channel models with diversity combining. Statistical Channel models include the Rayleigh Fading, Ricean Fading, and Nakagami Fading Channel. The spatial channel models include the Geometrical Based Single Bounce (GBSB) Circular and Elliptical Channel models. The simulation of statistical channels shows that the probability of error decreases as the SNR increase. The BER also improves by applying various diversity techniques and among the three diversity combining techniques applied viz. maximal ratio combining (MRC), equal gain combining (EGC), and selection combining (SC)., MRC shows the best performance. The performance of the antenna system also improves as the number of antenna elements is increased.