Distributed Uplink Macro Diversity for Cooperating Base Stations

Nowadays cellular systems operate with frequency reuse one, where adjacent cells use the same frequency band. Use Equipments (UEs) located at cell edge are mostly affected by the resulting co-channel interference. In addition, cell edge UEs suffer from their weak carrier signal strength. This paper proposes a new method to increase the performance of cell edge UEs by means of information exchange between Base Stations (BSs). A BS serving a cell edge UE requests support from a co-channel BS. The supporting BS transfers demodulated or decoded bits received from the cell edge UE back to the serving BS. The serving BS then combines the information. The concept of cooperative BSs described in this paper is based on a request-response mechanism and does not require a central control node. Performance evaluation by means of simulation shows the capability of BS cooperation applied to 3GPP Long-Term Evolution (LTE) in terms of user throughput and emphasizes the trade-off in terms of increased backhaul requirement due to BS-BS communication.