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Author: search.filters.author.Elujide, Israel Oludayo

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    Performance of local averaging handover technique in long term evolution networks
    (SAIEE, 2015) Elujide, Israel Oludayo; Olugbara, Oludayo O.; Nepal, Thiruthlall; Owolawi, Pius Adewale
    In this paper, we investigate the performance of an alternative received signal filtering technique based on local averaging to improve the quality of handover decisions in Long Term Evolution (LTE) networks. The focus of LTE-Advance (LTE-A) networks is to provide enhanced capacity and reliability of radio access as well as broadband demand for mobile users. The necessity to maintain quality of service, especially for the delay sensitive data services and applications, has made mobility and handover decisions between the base stations in the LTE networks critical. Unfortunately, several handover decision algorithms in the LTE networks are based on the Reference Signal Received Power (RSRP) obtained as a linear averaging over the reference signals. The critical challenge with the linear averaging technique is that the limited reference signal available in the downlink packet introduces an estimation error. This estimation error is a result of the effects of linear averaging on propagation loss components in eliminating fast-fading from the received signals. Moreover, prompt and precise handover decisions cannot be based on inaccurate measurement. The standardized LTE layer 3 filtering technique is applied to the local averaged layer 1 signal to render it suitable for LTE handover decisions. The local averaging technique produces better handover than the linear averaging technique in terms of the reduced number of handover failures, improved high spectral efficiency and increased throughput, especially for cell-edge users with high speeds. The findings of this study suggest that the local averaging technique enhances mobility performance of LTE-Advance networks.
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    Analysis of handover decision making in downlink Long Term Evolution networks
    (2015-01-15) Elujide, Israel Oludayo; Olugbara, Oludayo O.; Owolawi, P. A.
    This dissertation reports on handover in downlink Long Term Evolution (LTE) networks. The LTE is seen as the technology that will bring about Fourth Generation (4G) mobile broadband experience. The necessity to maintain quality of service for delay sensitive data services and applications used by mobile users makes mobility and handover between base stations in the downlink LTE very critical. Unfortunately, several handover schemes in LTE are based on Reference Symbols Received Power (RSRP) which include measurement error due to limited symbols in downlink packets. However, prompt and precise handover decision cannot be based on inaccurate measurement. Therefore, the downlink LTE intra-system handover is studied with focus on user measurement report. The study centers on preparation stage of the LTE handover procedure. Two different types of physical layer filtering technique namely linear averaging and local averaging are focused upon among others investigated. The performance of LTE conventional physical layer filtering technique, linear filtering, is compared with an alternative technique called local averaging. The output of each physical layer filtering is then used for LTE standardized radio resource layer filtering (otherwise called L3 filtering). The analysis of results from handover decision is based on simulations performed in an LTE system-level simulator. The performance metrics for the results are evaluated in terms of overall system and mobility-related performance. The system performance is based on spectral efficiency and throughput while mobility-related performance is based on handover failure. The performance comparison of the results shows that local averaging technique provides improved system performance of about 51.2 % for spectral efficiency and 42.8% cell-edge throughput for high speed users. Local averaging also produces a reduction of about 26.95% in average number of handover failure when L 3 filtering is applied for low speed mobile terminal. This result confirms that both averaging techniques are suitable for LTE network. Moreover, in the case of high mobility local averaging tends to be better than linear averaging.