Wavelet OFDM with Overlap FDE for non-Gaussian channels in precoded NOMA based systems

Walsh–Hadamard Transform Based Non-Orthogonal Multiple Access (NOMA) and Interference Rejection Combining in Next-Generation HetNets

“…Using in (34) instead of , in (33) gives us the desired signal by supressing the interference information. If the ideal IRC case is considered, then composite channels, i.e., from serving cell and all interferers, are known at the receiver, so the ideal IRC weight matrix at the UE-served by SBS will be given by using (34) as:…”

“…Theoretically, it is understandable that the complexity of the proposed system in this work should increase with the increment in the number of operations as compared to conventional NOMA. With the inclusion of IRC, the system becomes more complex due to the nature of the IRC weight matrix calculation, given from (34) and (36). Therefore, in this section, the complexity comparison, in terms of the required number of multiplications, is calculated for WHT-NOMA with IRC, compared to conventional NOMA, and is shown in Table 4 and Figure 22 [34,37,10], where represents the number of sub carriers and K represents the number of UEs performing IRC in the small-cell.…”

“…It increases the constellation diversity in the modulation schemes, hence resulting in reduced BER performance and enhanced subsequent user throughput. In recent years, a number of studies have been conducted using the WHT in communication systems; a joint investigation on the WHT and Alamouti scheme was performed in [30], a transceiver design for single carrier frequency division multiple access (SC-FDMA) was proposed using the WHT in [31], and similarly, the WHT was applied on spatial modulation in [32] and on NOMA in [33,34]. To the best of authors' knowledge, to date, no joint strategy has been proposed considering the WHT, NOMA, and IRC in HetNets, particularly under nonideal SIC conditions for NOMA.…”

Performance analysis of discrete wavelet transform for downlink non‐orthogonal multiple access in 5G networks

“…The insertion of CP offers a simple and easy solution to overcome the channel‐induced impairments. However, CP insertion leads to loss in overall throughput of the system and spectral efficiency due to the redundant use of bandwidth [11]. Therefore, the OFDM technique may not be an optimal option as a pulse‐shaping technique for 5G wireless communication networks, for which one of the major requirements is spectral efficiency.…”

“…In this research work, we employ W‐OFDM as a pulse‐shaping technique for the NOMA system in 5G networks since it offers several advantages such as spectral efficiency due to the absence of CP, reduced out of band radiations, sensitivity to loss of synchronisation, efficient peak to average power ratio (PAPR) performance and robustness against ISI due to the energy containment in the frequency domain [13]. So far, wavelet NOMA (W‐NOMA) has been investigated by a few research works [7, 11, 14, 15]. The main objective of this study is to add to this literature and further investigate W‐NOMA systems.…”