Improving Dense Network Performance through Centralized Scheduling and Interference Coordination

Dense network deployments comprising small cells pose a series of important challenges when it comes to achieving an efficient resource use and curbing inter-cell interference in the downlink. This article examines different techniques to treat these problems in a dynamic way, from the network and the
receiver sides. As a network coordination scheme, we apply a centralized joint cell association and scheduling mechanism based on dynamic cell switching, by which users are not always served by the strongest perceived cell. The method simultaneously resultsin more balanced loads and increased performance. Interference management at the receiver is achieved through the use of a Network-Assisted Interference Cancellation and Suppression (NAICS) receiver. In order to further boost the 5th percentile user data rates, the transmission rank at the interferers is selectively reduced by a centralized rank coordination functionality. These mechanisms are evaluated in an LTE-Advanced dense small cell scenario with dynamic traffic. Simulations results illustrate that a combination of the centralized cell association and scheduling scheme and interference cancellation at the receiver can provide 5th percentile data rate gains of up to 80% without a detrimental effect on the median user rates, under the applied assumptions and simulation settings. The gains reach 110% when rank coordination is applied.