Performance Analysis of Fractional Frequency Reuse Schemes in Downlink Multi-Relay Multi-Cell OFDMA and NOMA Cellular Networks

Date
2020-05-18
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Abstract
With the aim of increasing the demands of high data rates, improving spectral efficiency (SE), meeting quality of service (QoS) requirements, and increasing the energy efficiency (EE), frequency reuse schemes are the most promising approaches for achieving these targets and reducing the effects of interference in current and next-generation multi-cell cellular networks. Fractional frequency reuse (FFR) schemes are among the most of the frequency reuse schemes used to mitigate inter-cell interference (ICI), especially for outer zone users. Relaying with FFR schemes is considered an effective strategy for enhancing capacity and increasing cell coverage in a cooperative relaying cellular networks. This thesis develops an analytical frequency reuse patterns that minimize the effect of ICI for FFR schemes in cooperative and non-cooperative downlink orthogonal frequency division multiple access (OFDMA) cellular networks. In fifth generation (5G) and beyond wireless communication systems, non-orthogonal multiple access (NOMA) compares favourably to orthogonal multiple access (OMA) systems due to high SE, massive connectivity, and improved user fairness. In addition, NOMA utilizes power domain user multiplexing by using signal superposition at the transmitter and successive interference cancellation (SIC) at the receiver. This thesis develops Power allocation (PA) and user pairing (UP) algorithms to maximize the sum-rate of paired users for FFR schemes in downlink NOMA-based cooperative and non-cooperative relaying while accounting for the effect of ICI and imperfect SIC on the system performance. This thesis develops a novel SIC error factor formula for imperfect SIC scenarios that is used for evaluating the overall system performance. Finally, an analytical expression for the instantaneous signal-to-interference noise ratio (SINR) is developed for inner and outer zone paired users while taking into account ICI and imperfect SIC conditions in a cooperative relaying system. This expression is used to evaluate the achievable sum-rates and outage probability (OP) for both zone users in a cooperative relaying NOMA-based FFR scheme and is compared to a non-cooperative system. The research in this thesis offers the potential for enhancing system performance while reducing the impact of ICI. The numerical results validate the efficacy of the proposed schemes in enhancing the performance compared to their counterparts.
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Keywords
Fractional Frequency Reuse Schemes, Relays, OFDMA, NOMA, ICI
Citation
Saleh, A. M. M. (2020). Performance Analysis of Fractional Frequency Reuse Schemes in Downlink Multi-Relay Multi-Cell OFDMA and NOMA Cellular Networks (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.