Telecommunication Engineering

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Browsing Telecommunication Engineering by Subject "3G"

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    Optimization of Soft Handover for Addis Ababa UMTS Radio Access Network
    (Addis Ababa University, 2020-02) Nigussie, Beyene; Beneyam, Berehanu (PhD)
    Handover is an essential radio management technique of mobile communication to enable seamless communication while users move from one cell to another one. To mitigate impacts of interference on cell-edge users, third Generation (3G) supports soft handover where users can be simultaneously served by two or more cells, in addition to hard handover, where a user is served by only one cell. The number of soft handover users and their active cells determine the degree of soft handover overhead. The soft handover overhead data for the year 2018 of Addis Ababa 3G network is 87% average overhead, which is considerably beyond the maximum recommended value. This figure indicates the requirement to optimize the soft handover overhead using the soft handover related network parameters’ configurations. In this thesis, soft handover overhead performance of the Addis Ababa 3G network is analyzed. The spatial distribution of the overhead is visualized using data collected from the network management system. Furthermore, optimization of soft handover overhead is done through fine-tuning window add, pilot power, and electrical antenna down tilt. We apply a heuristic algorithm for the optimization considering potential sets of values for the optimization variables. Moreover, obtained results are compared with a result obtained using existing default network configuration parameters. For the sample 3G sites network simulation, we use WinProp while we also use MATLAB and Google Earth for soft handover performance analysis and visualization. Soft handover overhead performance analysis of 5 Radio Network controllers (RNCs) shows that the Addis Ababa network is within the range of 111 to 115% for the 90 th percentile. Sites in RNC4 using carrier three are selected for the simulation and optimization as 5 to 21 more number of radio links used comparing with the other three carriers. After optimization, results show that soft handover overhead and network capacity are considerably improved by fine-tuning the window add, pilot power, and antenna tilt parameters. For instance, soft handover overhead is reduced from 85.4 % to 57.7% and network capacity gain by 3.76% when using window add of 2 dB, pilot power of 7.5%, and electrical antenna down tilt by 2 degrees. Soft handover overhead is reduced from 85.4 % to 46.6% and network capacity gain by 5.72% when using window add of 1.5 dB, pilot power of 5% and electrical antenna down tilt by 3 degrees.
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    Quality of Experience Evaluation for Smartphone Video Streaming over 3G Network: In the case of Addis Ababa, Ethiopia
    (Addis Ababa University, 2019-12) Zelalem, Fitiwe; Mesfin, Kifle (PhD)
    Smartphones have become key enablers for users to exploit video streaming services such as YouTube, Hulu, Netflix. Quality of experience (QoE) represents the actual visual perception of users and it becomes a prominent concept. Considering the perception of users on the quality of mobile video streaming service evaluation is an important factor to assess the actual performance of the service that is provided to the users. So far, in Ethiopian Mobile Operator a combination of objective and subjective quality evaluation for video streaming service of mobile phone users, particularly for the most widely subscribed mobile 3G network, has not been performed. In this thesis work, video streaming QoE evaluation over the 3G network in case of Addis Ababa, for smartphone users is made using network-side data from NetProb3010 tool, crowdsourcing tools (YoMoApp and Speedcheck Pro) from the application side and perception of customers from the user side. The application and user side measurement results were collected from a field experiment campaign of 35 sample users after watching 8 different sample YouTube video sessions. In general, achieved video streaming metric results show that both subjective and objective metrics of QoE are not good and there is the unhappiness of smartphone customers with the current video streaming service quality. For example, based on NetProb3010 results the average initial delay is 19 seconds; the average number of stalling events is 0.38 times per minute and 6.46% for average stalled time rate. The application-level results show that the average initial delay, average number of stalling events, average stalled time duration and average video resolution watched results are 17.3 seconds, 0.47 times per 30 seconds, 3.79 seconds and 230P, respectively. Moreover, application-level average download throughput achieved during the experiment period is 1.78Mbps. The above objective metric results are reflected in the subjective metric (perception) result of the participants where the overall Mean Opinion Score (MOS) value is 2.79.