Capacity Analysis in Relay-assisted OFDM Systems Based on the Random Geometry Theory

This paper applies the random geometry theory to Decode-and-Forward (DF) relay-enhanced Orthogonal Frequency Division Multiplexing (OFDM) system and derives a new system capacity model finally. There are some assumptions that multiple users distribute uniformly in a ring region around Base Station (BS) and frequency is reused existing among users in access zone. By using the upper bound of interfere integral value to alternate the actual interfere value when considering the co-channel interference, the closed expression of system capacity is obtained under the power constraints of BS and relay nodes. Simulation results show the validity of the system capacity model.