Wireless communication systems, since their inception in the form of cellular communications, have spread rapidly throughout the western world and the trend is catching on in the developing countries as well. These sys- tems have caused revolutionary changes in the way we live. Cellular Commu- nications have become important both as means of communication and as a new domain ofcommercial enterprise. Hand held telephones are now rapidly replacing the fixed telephone and in less than twenty years, the number of subscribers has reached nearly three quarters of a billion. In a short span of...