Dynamic Clustering Based Sub-Band Allocation in Dense Femtocell Environments

In order to mitigate inter-femtocell interference (IFI) and utilize spectrum resource efficiently, this paper proposes a dynamic clustering-based sub-band allocation scheme (DCCSA). Firstly, DCCSA constructs a weighted interference graph base on the user measurement report mechanism. Secondly, according to the interference graph, the disjoint IFI-minimizing clusters are formed by a Max k-Cut clustering algorithm. Thirdly, a SINR-maximizing heuristic algorithm assigns sub-bands to each cluster. Finally, due to the time variation characteristic of the femtocell networks, a cognitive sub-band self-management mechanism is provided, especially to allocate the sub-band for the newly added femtocell, a reuse entropy based hybrid centralized/distributed interference-aware sub-band allocation algorithm is presented. Simulation results show that the DCCSA scheme can improve the throughput of femtocells and suppress the IFI significantly while guarantee the required QoS.