Pre-Buffering Scheme for Seamless Relay Handover in Relay Based Cellular Systems

Relay based cellular system, which includes Relay Nodes (RNs) to relay transmitters´ signal to receivers for coverage extension and capacity improvement, has been recently emerging as one of the candidates for next generation mobile communication system. However, Mobile Stations (MSs) in relay based cellular system suffer a problem of data loss when they move out of the coverage of the serving RN and perform handover to base station (BS) or other RNs. To prevent this behavior, this paper proposes a pre-buffering scheme that BS performs multicast transmission to the handover candidate RNs. After the MS detects a nearby RN and regards it as a candidate for the handover target, the MS requests BS to multicast the MS´s traffic to the serving and the candidate RN. The numerical and simulation results show that the proposed scheme brings performance improvement in view of data loss and handover interruption time.