Performance Study on Cooperative Relaying Topologies in beyond 3G Systems

Relaying has been proposed to support users suffering from high shadowing or high interference and therefore being not able to receive high data rates. With adaptive relaying, a higher Modulation and Coding Scheme (MCS) can be used in order to increase the feasible data rate. The investigation of relaying techniques widely has concentrated on information theoretical methods. Instead, this paper focuses on system level simulations to analyse the achievable results within a realistic environment. The question where to locate the Relay Stations is investigated and the achievable system performance is outlined. We show that relaying techniques can improve the median cell throughput and decrease the outage probability. Cooperative relaying results in the lowest outage probability, whereas the introduced concept of Dynamic Resource Relaying (DRR) offers a higher cell throughput. For the investigated LTE (3GPP Long Term Evolution) system with a frequency re-use factor of one, the outage probability can be decreased by using relaying and no further frequency planning is required.