Capacity enhancement using intelligent relaying for future personal communication systems

This paper highlights the key benefits of using intelligent relaying (IR) for future personal communication systems. IR is a technique that incorporates direct mobile to mobile communication, allowing end-to-end connectivity in a network to be implemented via a number of short hops. A mobile can in theory reach any destination by transmitting only as far as its closest neighbour bringing potential benefits such as an overall reduction in transmit power and the possibility of increased capacity. In addition, the self-organising nature of the network may reduce the need for network planning and basestation infrastructure. Disadvantages include an overall increase in complexity, and the problem of a particular user's terminal being used for the benefit of others. Results are presented that quantify the gains in capacity that can be brought about by the lower levels of interference due to reduced transmit power throughout a sample test network. A simulation platform is described which uses IR as an enhancement to a hybrid TDD/CDMA air interface similar to the UTRA TDD mode. It is shown that capacity can be increased although this capacity gain is dependent an there being a sufficient number of users available to act as relays.