In the latest decade we have witnessed a tremendous advance in telecommunications technology. With the rapid growth and sophistication of digital technology and computers, communication systems have become more versatile and powerful. This has given a modern communication engineer two key problems to solve: (i) how to handle the ever-increasing demand for capacity and speed in communication systems, and (ii) how to tackle the need to integrate a wide range of computers and data sources so as to form a highly integrated communication network with a global coverage
