Novel Cell-Sweeping Deployment Scheme for Coverage Enhancement in Cellular Networks
Creators: name: Borralho, Rúben Alexandre Guerra
Publisher: name: University of Surrey
Year: 2023

description: In this thesis, a novel concept of cell-sweeping based Base Station (BS) deployment in the Radio Access Network (RAN) for coverage enhancement in cellular systems was investigated. This new concept arises from the existing and expected challenges in providing proper network coverage, within a continuous changing environment with ever increasing demand and requirements.<br>
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description: Through a deep literature investigation of coverage in cellular networks, the main mechanisms for coverage enhancement were firstly identified and a new taxonomy to categorise them was defined. Additionally, this study allowed to understand the current stage of mobile coverage, highlighting the issues and challenges that have been faced and that are expected to increase in the upcoming years.<br>
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description: The first major contribution of this thesis consists of proposing a novel solution to overcome one of the main issues affecting network coverage, the cell-edge problem. The new concept of cell-sweeping is introduced and its main characteristics and configuration parameters are detailed. Its impact in the antenna radiation pattern is derived and algorithm is presented. The proposed scheme’s gains are measured through computer simulations by comparing the 5th-percentile of received power, Signal-to-Interferenceplus-Noise ratio (SINR), and throughput performance with recent BS cells deployments. This metric is typically used to assess the cell-edge. Results show a 60% to 70% improvement of the 5th-percentile of the wideband SINR using the proposed method without any average network performance degradation. <br>
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description: Secondly, a mathematical framework to model the cell-sweeping operation was developed. This allows to derive and evaluate the cell-sweeping performance impact on different coverage related key performance indicators (KPIs), such as the probability density function (PDF) and cumulative density function (CDF) of wideband SINR and data rate based upon the Shannon capacity formula. These are derived and analysed under different environment characteristics. The numerical results validate the mathematical model by means of computer simulations.<br>
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description: Finally, the cell-sweeping was implemented and its performance was evaluated in a system-level simulator which provides a realistic cellular radio environment. It also allowed to model multipath small-scale fading as well as scheduling policies. This then allowed to evaluate the cell-sweeping concept in a wide range of different scenarios, where throughput, energy-efficiency, and cell radius/area expansion benefits are added to the enhanced coverage results. It was observed that the cell-sweeping leads to cell-edge and average throughput gains of up to 125% and 35%, respectively. Additionally, it was demonstrated by means of link budget analysis that the cell-sweeping allows cell radius extension and cell area expansion of up to 29% and 66%, respectively, without performing below the conventional cell-deployments from a coverage perspective.<br>