Feasibility study of relay in 3GPP LTE-advanced from a coexistence perspective

Relay technologies have been actively studied and considered as one of the most important technical components in 3GPP LTE-Advanced. LTE Advanced networks with relays and traditional LTE-networks may operate in the same geographical area in adjacent channels. The coexistence issue between the two systems is becoming urgent in the standardization of relay in LTE-advanced. In this paper, the feasibility of relays in LTE-Advanced is studied from a coexistence perspective. We discuss the classification of relays and how they work in the current system in the first place. Then we present the Adjacent Channel Interference Ratio (ACIR) model and the relay coexistence methodology. Different coexistence scenarios when LTE and LTE-Advanced are deployed in adjacent frequency bands are then investigated. Finally, simulation results such as the throughput loss are given with different Radio Frequency (RF) parameters. Simulation results show that relay nodes can coexist with LTE systems under current RF system parameters.