A packet based system for cellular digital mobile radio applications

Third generation mobile radio systems will be required to operate in a wide variety of environments from indoor picocells to outdoor macrocells. In addition the range of services accommodated will increase relative to existing systems. The implications are that a single air interface is unlikely to satisfy overall demands and that the emphasis must therefore be on flexibility. The paper examines the prospects of packet transmission to provide the necessary flexibility and draws attention to some of the issues which the implementation of packet access raise. The primary advantage of packet transmission is that bandwidth may be allocated on a demand basis. In voice communications if packet transmission is restricted to periods of voice activity this technique offers a theoretical improvement over fixed-allocation TDMA systems by a ratio in excess of 2:1, depending on the voice activity detector. Other potential advantages of packet transmission include the service independent nature of transmission (voice, video, data) and the ability to accommodate variable bit rate services