Studies on broadcast channel over fading channels

Abstract

The radio communication system design is limited by the fading process. Diversity

techniques are used to combat fading in wireless communication system over a time

varying channel. The transmit diversity provides the same order of diversity gain as

the receiver diversity. The transmit diversity has reached greater heights in certain

areas of application, where the receiver diversity technique cannot be used. It has

also been known that zero forcing precoding is an attractive technique for wireless

communication due to its ability to reduce multiple access interference (MAl).

Zero forcing precoding technique is used at the transmitter, where channel inverse

matrix is multiplied with the transmitted signal. This is done to nullify the effect of

the channel impairment. The power control technique is used to maintain constant

transmitted power for all the users in the broadcast station. This technique mitigates

the near far effect. Through this technique the access for far users will not be affected

by the strong near users.

Recently exact analysis of zero forcing precoding technique has been presented in

the literature. The contribution of the project is the implementation of zero forcing

precoding and power control on a multiple input and multiple output communication

system over a Rayleigh flat fading channel. The results are presented in graphical

form.