Performance Evaluation in Heterogeneous Networks Employing Time-Domain Inter-Cell Interference Coordination and Cell Range Expansion for LTE-Advanced Downlink

Masashige SHIRAKABE  Akihito MORIMOTO  Nobuhiko MIKI  

Publication
IEICE TRANSACTIONS on Communications   Vol.E95-B   No.4   pp.1218-1229
Publication Date: 2012/04/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E95.B.1218
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Cognitive Radio and Heterogeneous Wireless Networks in Conjunction with Main Topics of CrownCom2011)
Category: 
Keyword: 
LTE-Advanced,  heterogeneous networks,  inter-cell interference coordination,  cell range expansion,  

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Summary: 
In Long-Term Evolution (LTE)-Advanced, heterogeneous networks where femtocells and picocells are overlaid onto macrocells are extensively discussed in addition to traditional well-planned macrocell deployment to improve further the system throughput. In heterogeneous network deployment, combined usage of inter-cell interference coordination (ICIC) and cell range expansion (CRE) is very effective in improving the system and cell-edge throughput. In this combined usage, the fraction of the sets of user equipment (UEs) connected to the picocells, which are controlled through CRE, and that connected to macrocells affect the gain from the ICIC. Therefore, this paper evaluates the throughput performance of different offset values for CRE and different amounts of protected resources for ICIC in picocell deployments in LTE-Advanced downlink. Simulation results (2–10 picocells and 30 UEs are located within 1 macrocell) assuming a full buffer traffic model show that when the CRE offset value is set between 8 to 20 dB, almost the same user throughput performance is obtained by allocating the appropriate resources to protect UEs that connect to the picocells. Furthermore, the appropriate resource ratio is derived based on the fraction of UEs connected to the picocells through CRE, the fraction of UEs connected to the macrocell, and the number of picocells under the simulation conditions.