Inter-Cell Interference Mitigation in LTE-Advanced Network by Using Coordinated Multipoint Transmission Technique: The Case of Addis Ababa, Ethiopia

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Date

2021-10

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Addis Ababa University

Abstract

The number of mobile broadband subscribers is increasing along with mobile data traffic on the Ethiopian mobile network. Mobile customers are facing dissatisfied service quality as the number of subscribers is increasing due to resource sharing as well as increasing interference. To improve service quality, network optimization and expansion work has been continuously performed. In order to maximize network capacity and coverage, ethio telecom upgrading the cellular network by using Long Term Evolution Advanced (LTE-A), an indoor building solution system, and adding base stations/transmitters. In such networks, Inter-Cell Interference (ICI) becomes more challenging, which mainly affects network performance. So, to overcome the aforementioned problem, operators are required to develop an effective approach that adopts different interference mitigation techniques. This thesis study presents a Coordinated MultiPoint (CoMP) transmission technique that can be considered as an effective way to improve spectral efficiency and system throughput performance. The thesis focused on downlink ICI mitigation in the LTE-A network within Addis Ababa. Comparative analyses and evaluations were performed for various CoMP and non- CoMP schemes. Taking into account performance metrics such as Signal to Interference plus Noise Ratio (SINR), spectral efficiency, and system throughput by performing radio propagation using WinProp and system-level simulation using the static simulator Matlab. The performance evaluation of the simulation study results obtained that the SINR gain improves 1.2dB and 1.4dB for the intra-site CoMP system, the Dynamic Point Blanking (DPB) CoMP system improves up to 3dB and 1.9dB, and the Joint Transmission (JT) CoMP system improves 3.7dB and 2.8dB for the cell edge and average users respectively. Spectral efficiency gain improved by 1.4bps/Hz, 2.4bps/Hz, and 3.2bps/Hz for intra-site CoMP, DPB CoMP, and JT CoMP scenarios, respectively. In addition, the throughput gain was achieved at 33% and 15% for intra-site CoMP, 70%, and 45% for DPB CoMP, and 97% and 70% for JT CoMP for the cell edge and average users, respectively. Therefore, the proposed interference mitigation solutions have been proven to provide a significant performance improvement for the LTE-A network and are worthy of deployment on the existing Addis Ababa LTE-A networks.

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Keywords

LTE-Advanced network, Inter-cell interference, Interference management technique, Coordinated multipoint, Joint processing, SINR, Throughput, Addis Ababa

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