Centralized and Distributed Solutions for Fast Muting Adaptation in LTE-Advanced HetNets

Enhanced intercell interference coordination (eICIC) is known to provide promising performance benefits for Long-Term Evolution Advanced heterogeneous networks (LTE-Advanced HetNets). The use of eICIC facilitates more flexible interlayer load balancing by means of small-cell range extension (RE) and almost blank subframes (ABSs). Although the eICIC configuration (RE and ABS) ideally should be instantaneously adapted to follow the fluctuations of the traffic and the channel conditions over time, previous studies have focused on slow intercell coordination. In this paper, we investigate fast-dynamic eICIC solutions for centralized and distributed radio resource management (RRM) architectures. The centralized RRM architecture assumes macrocells and remote radio heads (RRHs) interconnected via high-speed fronthaul connections, whereas the distributed architecture is based on traditional macrocell and picocell deployments with an X2 backhaul interface. Two different fast muting adaptation algorithms are derived, and it is shown how those can be applied to both the centralized and distributed architectures. Performance results with bursty traffic show that the fast-dynamic adaptation provides significant gains, both in fifth-percentile and 50th-percentile user throughputs, and improvements in user fairness. The best performance is naturally obtained for the centralized architecture, although the performance of the distributed architecture is comparable for the cases where enhanced X2 intercell information exchange is exploited.