الفهرس 
Chapter (1) IntroductionOnly 14 pages are availabe for public view
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Abstract
Recently, the fifth generation (5G) networks have been heavily investigated in order to support a wide range of applications with different requirements. These applications have been organized in three different types of services: extreme mobile broadband (xMBB), massive machine-type communication (mMTC), and ultra-reliable low latency communication (URLLC), where these applications feature 20 Gb/s peak data rate, 106 devices/km2 connection density, and less than 1 ms latency, respectively. In order to meet such demanding requirements, formidable research challenges have been placed in front of wireless engineers, the very first of which is choosing the appropriate waveform generation technique, which is a shaping component of any air interface. The 5G waveform candidates have been proposed in the “5G Non-orthogonal waveforms for asynchronous signaling” (5GNOW) project and can be classified into two categories: 5G waveforms based legacy orthogonal frequency division multiplexing (OFDM) transceivers, which can be considered as straightforward enhancements of OFDM, including windowed-OFDM (W-OFDM), filtered-OFDM (F-OFDM), and universal filtered multicarrier (UFMC). The second category utilizes 5G waveforms based new transceiver structures, including filter-bank multicarrier (FBMC) and generalized frequency division multiplexing (GFDM).
The focus of this thesis is on the UFMC as a recent waveform candidate for 5G systems, in which the filtering operation is applied to a group of consecutive subcarriers instead of filtering the whole band as in OFDM or filtering individual subcarriers as in FBMC. The UFMC system performance shows a reduction in the out-of-band emissions (OoBE), where the effect of sidelobe interference on the immediate adjacent subchannels is significantly reduced and hence providing better robustness against intercarrier interference (ICI). In general, the UFMC system can be considered as an intermediate technique between OFDM and FBMC, which combines the simple implementation of OFDM and the robustness of FBMC against interference. Although, the UFMC system offers many advantages as mentioned before, but being a multicarrier transmission technology, it suffers from high peak-to-average power ratio (PAPR). Also, the increased computational complexity of the UFMC receiver due to doubling the size of the fast Fourier transform (FFT) is another main drawback.
In this thesis, an efficient selected mapping (E-SLM) approach is proposed for PAPR reduction in UFMC systems. The proposed approach features complexity reduction compared to classical SLM approach with the same PAPR reduction ability. Also, in the same way a modified selected mapping (M-SLM) approach with low-complexity is proposed for reducing PAPR in UFMC systems. The main idea of the proposed M-SLM approach is to utilize the linearity property of the UFMC modulator to generate more alternative UFMC waveforms compared to SLM and E-SLM approaches using the same number of UFMC modulators. Therefore, the computational complexity of the M-SLM approach is reduced compared to the existing SLM based PAPR reduction approaches for UFMC systems. The M-SLM approach is compared to the other approaches found in the literature in terms of PAPR reduction ability, bit error rate (BER) performance, and the computational complexity.
This thesis also presents a novel blind PAPR reduction approach which has been applied to E-SLM and M-SLM UFMC systems. The simulation results show that the proposed blind approach is very attractive for UFMC systems since the PAPR reduction ability of the proposed blind approach is identical to the classical approaches. Additionally, a modified receiver for UFMC systems is proposed in this thesis in order to improve its BER performance. In the conventional UFMC receiver, only the even-indexed samples are taken into consideration to recover the original data while the odd-indexed samples are discarded. The proposed modified receiver makes use of the odd-indexed samples since they also contain useful information about the original data. Consequently, the proposed receiver utilizes all the samples in order to achieve better BER performance.
Keywords: Fifth generation (5G), extreme mobile broadband (xMBB), massive machine-type communication (mMTC), ultra-reliable low latency communication (URLLC), 5G Non-orthogonal waveforms for asynchronous signaling (5GNOW), orthogonal frequency division multiplexing (OFDM), windowed-OFDM (W-OFDM), filtered-OFDM (F-OFDM), universal filtered multicarrier (UFMC), filter-bank multicarrier (FBMC), generalized frequency division multiplexing (GFDM), out-of-band emissions (OoBE), intercarrier interference (ICI), peak-to-average power ratio (PAPR), fast Fourier transform (FFT), efficient selected mapping (E-SLM), modified selected mapping (M-SLM), and bit error rate (BER).