University of Khartoum

Optimization of Cognitive Radio Spectrum Utilization through Predictive Spectrum Sensing

Optimization of Cognitive Radio Spectrum Utilization through Predictive Spectrum Sensing

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Title: Optimization of Cognitive Radio Spectrum Utilization through Predictive Spectrum Sensing
Author: Saad, Hind Ali Mohammed
Abstract: Cognitive Radio (CR) technology enables improving the utilization efficiency of the precious and scarce radio spectrum. This work investigates the cognitive radio operations and basic principles of Medium Access Control (MAC) designs in spectrum sharing models. Furthermore, it demonstrate the impact of using different sensing techniques in CR networks and the opportunistic usage of spectrum holes with least possible interference with Primary User (PU). Users in the CR network must determine which portions of the spectrum are available, select the best available channel, coordinate access to this channel with other users and vacate the channel when a licensed user is detected. A number of spectrum sensing techniques had been proposed in the literature to identify the state of the primary user in the temporal domain. Research problem can be summarized in that, most sensing techniques make instantaneous decisions based on current measurement received at the cognitive radio, and they do not consider the transmission pattern of the primary user which can be acquired from past measurements. Thus, this work introduces a prediction based spectrum sensing scheme that improves ED sensing process by using prediction of spectrum availability to enhance spectrum utilization and save sensing energy. The sensing scheme compromises the channel availability prediction and sensing processes to improve the ability of correctly and quickly performing SU channel allocations. The predictive knowledge can be used to overcome the negative impact of response delays caused by hardware platforms and reduce the power consumption. This scheme is built up as a means of improving the sensing performance and reducing the sensing time and energy consumption by enabling the CR nodes to sense the channels that are predicted to be unoccupied rather than the entire band of interest. The performance of the proposed scheme is analyzed in terms of its prediction performance. Based on this approach, a spectrum occupancy predictor is developed and experimentally validated through MATLAB software simulations. Significant Secondary User (SU) performance improvements were observed when prediction modeling was employed. The new scheme achieves an average prediction accuracy of 87% which in turn can lead to up to 68% reduction of the spectrum sensing energy and the percentage improvement in channel utilization is up 79.9%
Description: 100 Pages
URI: http://khartoumspace.uofk.edu/123456789/27132
Date: 2018-09


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