On attachment optimization and muting pattern selection in eICIC

Enhanced Inter-Cell Interference Coordination (eICIC) is a mechanism introduced in LTE Advanced for controlling interference in heterogeneous mobile networks. To operate eICIC efficiently, the attachment of User Equipment (UE)s to Evolved Node B (eNB) base stations and the muting patterns must be optimized. Usually, the UE to eNB attachment is optimized by varying the Cell Specific Offsets (CSO)s that determine the size of the small cells. However, these Cell Range Expansion (CRE) based optimization methods do not consider all possible UE to eNB attachments. In this paper we propose a new method for optimizing the UE attachments that is not based on the traditional CRE approach, considers all UE attachment possibilities and is computationally efficient. We compare the performance of the proposed method with a typical CRE based method in an example network. Muting pattern selection is also investigated in the example network, and the results show that limiting the number of muting patterns to a set satisfying certain practical constraints gives nearly the same performance as always selecting the best of the considered patterns.