Introduction

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book focuses on the design of various PHYsical and Medium Access Control layer mechanisms for the efficient implementation of Orthogonal Frequency Division Multiplexing/Multiple Access-based two-hop cellular networks. It gives the background on cooperative communications. The book provides analytical derivations, look-up tables and extensive analysis on the conditions where relaying should be used in a practical system setup. It focuses on the development of link adaptation mechanisms which consider the end-to-end optimization in wireless relay networks. The book addresses various implementation issues for the successful implementation of wireless relay networks. Some relaying schemes necessitate simultaneous transmissions from the source and the relay terminals. This may lead to some synchronization problems such as time and frequency offset. Cooperative diversity achieved in the form of coherent signal combining increases the complexity at the mobile station.