Walsh Hadamard transform based transceiver design for SC-FDMA with discrete wavelet transform

Khan, Arsla; Arif, Amna; Nawaz, Tabassum; Baig, Shams Ali

doi:10.1109/cc.2017.7942326

Cited by 10 publications

(4 citation statements)

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“…The outcome of synthesis filters is then simply summed up to acquire the original signal. It is very crucial to draw the attention of the reader that the synthesis procedure should be extended for a similar number of levels for which the decomposition process was carried out [57].…”

Section: Dwt Based Hybrid Multi-carrier Cdmamentioning

confidence: 99%

Doubly Orthogonal Wavelet Packets for Multi-Users Indoor Visible Light Communication Systems

et al. 2019

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Visible Light Communication (VLC) is a data communication technology that modulates the intensity of the light to transmit the information mostly by means of Light Emitting Diodes (LEDs). The data rate is mainly throttled by the limited bandwidth of the LEDs. To combat, Multi-carrier Code Division Multiple Access (MC-CDMA) is a favorable technique for achieving higher data rates along with reduced Inter-Symbol Interference (ISI) and easy access to multi-users at the cost of slightly reduced compromised spectral efficiency and Multiple Access Interference (MAI). In this article, a multi-user VLC system is designed using a Discrete Wavelet Transform (DWT) that eradicates the use of cyclic prefix due to the good orthogonality and time-frequency localization properties of wavelets. Moreover, the design also comprises suitable signature codes, which are generated by employing double orthogonality depending upon Walsh codes and Wavelet Packets. The proposed multi-user system is simulated in MATLAB software and its overall performance is assessed using line-of-sight (LoS) and non-line-of-sight (NLoS) configurations. Furthermore, two sub-optimum multi-users detection schemes such as zero forcing (ZF) and minimum-mean-square-error (MMSE) are also used at the receiver. The simulated results illustrate that the doubly orthogonal signature waveform-based DWT-MC-CDMA with MMSE detection scheme outperforms the Walsh code-based multi-user system. Keywords: visible light communication (VLC); LED; photo-diode (PD); line-of-sight (LoS); non-line-of-sight (NLoS); multi-carrier code division multiple access (MC-CDMA); discrete wavelet transform (DWT); doubly orthogonal wavelet packets (DOWP); multiple access interference (MAI); minimum-mean-square-error (MMSE) IntroductionWith unprecedented demand for high-speed multi-media mobile services, optimization of wireless communication systems has become critical. Due to the limited range of frequencies, radio-frequency (RF) technology is unable to fulfill the needs for the current demands of mobile users [1]. As we are advancing towards 5G, the necessity for the evolution in broadband communication technologies has grown to its peak. The 5G communication networks have already defined performance requirements in which high-speed data delivery (expected to be 10 Gbps) and low latency (less than 1 ms) are the key performance parameters [2]. Visible Light Communication (VLC) is a completely new paradigm that is going to revolutionize the next generation of wireless communication by making use of a visible

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Section: Dwt Based Hybrid Multi-carrier Cdmamentioning

confidence: 99%

Doubly Orthogonal Wavelet Packets for Multi-Users Indoor Visible Light Communication Systems

et al. 2019

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“…Compared with Fourier transform and short-time Fourier transform, wavelet transform is based on the localization analysis of time and frequency. 44 Wavelet transform can multi-scale refine the signal by calculating flex and transition. It can extract feature information of the signal effectively, and it can find the location and the amplitude of outliers.…”

Section: Mathematical Model and Classification Algorithmmentioning

confidence: 99%

Wavelet transform and cyclic cumulant based modulation classification in wireless network

Dou

2019

International Journal of Distributed Sensor Networks

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With the development of Internet of things, a large number of embedded devices are interconnected by ad hoc and wireless network. The embedded devices can work correctly, only by ensuring correct communication between them. Identifying modulation scheme is the precondition to ensure the correct communication between embedded devices. However, in the multipath channel, ensuring the correct communication between embedded devices is a great challenge. Multipath channel always exists in the wireless network. However, most of the available modulation classification algorithms are based on ideal channel. It leads to the low-modulation classification probability in multipath channel. To resolve this problem, we propose a novel modulation classification algorithm. The proposed algorithm can classify signal without prior information about multipath channel. We calculate feature by high-order cyclic cumulant and wavelet transform. The feature is robust to multipath channel. The simulation results show that the proposed algorithm can achieve the much better classification accuracy than the available method in multipath channel.

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Usman

Shin

et al. 2021

Mathematics

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In heterogeneous networks (HetNets), non-orthogonal multiple access (NOMA) has recently been proposed for hybrid-access small-cells, promising a manifold network capacity compared to OMA. One of the major issues with the installation of a hybrid-access mechanism in small-cells is the cross-tier interference (intercell interference (ICI)) caused by the macrocell users (MUs) that are unable to establish a connection to the small-cell base station (SBS). In this paper, a joint strategy is proposed for hybrid-access small-cells using the Walsh–Hadamard transform (WHT) with NOMA and interference rejection combining (IRC) to achieve high performance gains and mitigate intercell interference (ICI), respectively. WHT is applied mathematically as an orthogonal variable spreading factor (OVSF) to achieve diversity in communication systems. When applied jointly with NOMA, it ensures better performance gains than the conventional NOMA. It reduces the bit error rate (BER) and enhances subsequent throughput performance of the system. IRC is used at the receiver side for managing the cross-tier interference caused by MUs that are unable to connect to the small-cell base station (SBS) for hybrid-access. The work considers both ideal and nonideal successive interference cancellation (SIC) conditions for NOMA. Mathematical modeling is provided for the proposed joint strategy for HetNets and the results validate it in terms of BER and subsequent user throughput performance, compared to the conventional NOMA approach.

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Walsh Hadamard transform based transceiver design for SC-FDMA with discrete wavelet transform

Cited by 10 publications

References 0 publications

Doubly Orthogonal Wavelet Packets for Multi-Users Indoor Visible Light Communication Systems

Doubly Orthogonal Wavelet Packets for Multi-Users Indoor Visible Light Communication Systems

Wavelet transform and cyclic cumulant based modulation classification in wireless network

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

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