Beamforming and Interference Cancellation for Half Duplex Relaying

Using relays to extend the coverage of base-stations in cellular systems has been of interest in recent years as it can reduce the cost of installing more base-stations and yet cater to mobile terminals within a wider coverage area. There have been recent advances where two or more half duplex relay stations are used to recover the loss of bandwidth due to the use of half duplex relays. However, such schemes would not be beneficial in cases where the inter-relay channel is strong, and the relays start interfering each other. In this paper, we study the use of beamforming techniques to resolve the problem of inter-relay interference.