Ad Hoc Cooperation for the Cellular Uplink with Capacity Constrained Backhaul

Base station cooperation is a promising solution to the interference limitation of today´s cellular networks. The capacity and fairness gains shown by information theoretical analysis of base station cooperation in cellular networks are huge. However, a major downside of base station cooperation is the additional information exchange among base stations which is the motivation for recent work on backhaul efficient cooperation schemes. In this paper, we show how imperfect channel knowledge which is caused by a scheduling delay affects the performance of a backhaul constrained base station cooperation scheme. Using the example of a distributed antenna system, we investigate the benefits of a cooperation scheme which takes the varying channel state into account to make ad-hoc decisions about the required accuracy of exchanged information. Ad hoc cooperation is shown to give very good results, and is thus an effective means to counteract the influence of outdated channel information of the scheduler.