ABSTRACT
This chapter analyzes the relaying technique at link and system levels from both spectrum efficiency and energy efficiency perspectives. It addresses the challenge of designing and positioning relay nodes (RNs) in a state-of-the-art wireless cellular system, namely Long Term Evolution system, coupled with practical power consumption models. The basic idea behind relaying is to use some radio nodes, called relays, in order to enable more spectrum and energy efficient communications. The relaying model was first introduced by van der Meulen, where a communication system with three nodes denoted as source, RN and destination, respectively, was investigated. Relay is usually classified as inband relay when the same carrier frequency is used for the backhaul and access links and outband relay when different carrier frequencies are used for these links. A mobile relay architecture, where relay can change their base station attachment according to operation demand, will promise more resilient and flexible relay deployment.
