Performance Evaluation of Space Diversity for Wireless Communication

Abstract

In wireless communications, diversity techniques are widely used to reduce the effects of multipath fading and improve the reliability of transmission without increasing the transmitted power or sacrificing the bandwidth. For spectral efficiency and improved Bit Error Rate, diversity provides an attractive option. Providing different replica of transmitted signal to the receiver is called diversity. There are many diversity techniques and among them space diversity technique is taken into main consideration in this thesis. During the detail study of Space Diversity one of the main reference paper was Sivash M. Alamouti ‘A Simple Transmit Diversity Technique For Wireless Communication’ 1998. This paper gives the possibility of transmit diversity with the use of BPSK as a modulation technique and Rayleigh as a fading model. Higher modulation technique such as QPSK is bandwidth efficient technique over BPSK and other fading model such as Ricean also exist in the environment. Rayleigh fading model is used when there are many objects in the environment where the signal is transmitted, resulting in the scatter of the signal before arriving at the receiver end. If the environment is such that, there is a presence of dominant path along with scattering between transmitter and receiver, then such situation is better modeled with Ricean fading model. Implementation of QPSK modulation technique and Ricean fading model along with the essential finding of this paper will be a additional benefit in space diversity technique. Simulated result shows that bandwidth efficient result with slightly higher BER in both receive diversity and transmit diversity is obtain from QPSK and very much low BER is obtain in Ricean fading model than that of the Rayleigh fading model which was proposed in the paper.