scholarly journals Improving Spectral Efficiency in the SCMA Uplink Channel

Mathematics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 651
Author(s):  
Sergio Vidal-Beltrán ◽  
José Luis López-Bonilla
Keyword(s):  
Mobile Communications ◽  
Antenna Arrays ◽  
Spectral Efficiency ◽  
Communication Systems ◽  
Multiple Access ◽  
Machine Intelligence ◽  
Spatial Modulation ◽  
International Telecommunication Union ◽  
Technical Requirements ◽  
Simulation Results

The Third Generation Partnership Project (3GPP) and the International Telecommunication Union (ITU) identified the technical requirements that the fifth generation of mobile communications networks (5G) had to meet; within these parameters are the following: an improved data rate and a greater number of users connected simultaneously. 5G uses non-orthogonal multiple access (NOMA) to increase the number of simultaneously connected users, and by encoding data it is possible to increase the spectral efficiency (SE). In this work, eight codewords are used to transmit three bits simultaneously using Sparse Code Multiple Access (SCMA), and through singular value decomposition (SVD) the Euclidean distance between constellation points is optimized. On the other hand, applications of machine intelligence and machine intelligence in 5G and beyond communication systems are still developing; in this sense, in this work we propose to use machine learning for detecting and decoding the SCMA codewords using neural networks. This paper focuses on the Use Case of enhanced mobile broadband (eMBB), where higher data rates are required, with a large number of users connected and low mobility. The simulation results show that it is possible to transmit three bits simultaneously with a low bit error rate (BER) using SVD-SCMA in the uplink channel. Our simulation results were compared against recent methods that use spatial modulation (SM) and antenna arrays in order to increase spectral efficiency. In adverse Signal-to-Noise Ratio (SNR), our proposal performs better than SM, and antenna arrays are not needed for transmission or reception.

scholarly journals LARGE-SCALE MIMO MC-CDMA SYSTEM USING COMBINED MULTIPLE BEAMFORMING AND SPATIAL MULTIPLEXING

2018 ◽  
Vol 56 (1) ◽  
pp. 102 ◽  
Author(s):  
Nguyen Huu Trung ◽  
Doan Thanh Binh
Keyword(s):  
System Performance ◽  
Code Division Multiple Access ◽  
Communication Systems ◽  
Multiple Access ◽  
Large Scale ◽  
Spatial Multiplexing ◽  
Propagation Loss ◽  
Fifth Generation ◽  
Simulation Results ◽  
Code Division Multiple

This paper proposes a novel Large-scale (massive) Multi-input Multi-output Multi-carrier Code division multiple access (LS MIMO MC-CDMA) model and application to Fifth-Generation Mobile Communication Systems (5G). This system uses combined cylindrical array antenna multiple beamforming architecture with spatial multiplexing. The model is optimized by Min-Max criteria in order to minimize side lobes and maximize compression of propagation loss. The Monte Carlo simulation results unify with the analytical solution for system performance.

scholarly journals 5G UFMC Scheme Performance with Different Numerologies

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1915
Author(s):  
Lambros Sakkas ◽  
Eleftherios Stergiou ◽  
Georgios Tsoumanis ◽  
Constantinos T. Angelis
Keyword(s):  
Mobile Communications ◽  
Bit Error Rate ◽  
Communication Systems ◽  
Modulation Scheme ◽  
Fifth Generation ◽  
Data Rates ◽  
The World ◽  
Simulation Results ◽  
5G Systems ◽  
Ber Performance

5G is the latest mobile communications standard that is spreading fast across the world. Recently defined requirements for 5G systems have led to higher applications’ requirements regarding data rates, lower requirements for latency, and higher efficiency regarding the spectrum usage. Universal Filtered Multi-Carrier (UFMC) is one new candidate modulation scheme for emergent Fifth Generation (5G) communication systems. This paper focuses on Universal Filtered Multi-Carrier (UFMC) design aspects in terms of Bit Error Rate (BER) performance in relation to the filter length used in subband filtering. Simulation results show that BER and CCDF performance varies for different filter lengths and modulation schemes. The main achievement of this work is that the results show that different Dolph–Chebyshev FIR filter lengths do not affect the BER performance both for the 64 and 256 QAM.

Dual-band (28/38 GHz) MIMO Antenna System for 5G Mobile Communications with Efficient DoA Estimation Algorithm in Noisy Channels

2021 ◽  
Vol 36 (3) ◽  
pp. 282-294
Author(s):  
Asmaa Farahat ◽  
Khlaid Hussein
Keyword(s):  
Mobile Communications ◽  
Communication Systems ◽  
Doa Estimation ◽  
Antenna System ◽  
Dual Band ◽  
Linear Antenna ◽  
Mimo Antenna ◽  
Single Antenna ◽  
Simulation Results ◽  
5G Mobile Communications

In this paper, a dual-band (28/38 GHz) linear antenna arrays of four and eight elements are proposed to work as a MIMO arrays for the 5G communication systems. Each element in the array is a dual-band Yagi-Uda antenna designed to operate at 28 and 38 GHz. The eight-elements array size has a total dimension of 79.4 mm x 9.65 mm excluding the feeding microstrip line. The maximum gain of the array is about 18 dB. The peaks of correlation at matched angles (PCMA) technique is applied to determine the direction of arrival for multiple incoming signals. The effects of phase noise and additive Gaussian noise on the error in the DoA estimation are studied showing good accuracy of the PCMA algorithm. Numerical and experimental investigations are achieved to assess the performance of both the single-element antenna and the eight-element MIMO linear antenna array. It is shown that the simulation results agree with the experimental measurements and both show good performance of the single antenna as well as the MIMO linear array system. The envelope correlation coefficient (ECC) and the diversity gain (DG) are calculated and the results show that the proposed MIMO antenna system is suitable for the forthcoming 5G mobile communications. The radiation patterns for single antenna and four-element array are measured and compared to the electromagnetic simulation results showing good agreement.

An improved peak side lobe reduction method for linear array antenna for military applications

2021 ◽  
Vol 14 (2) ◽  
pp. 186-198
Author(s):  
Ravi Tej D ◽  
Sri Kavya Ch K ◽  
Sarat K. Kotamraju
Keyword(s):  
Energy Efficiency ◽  
Antenna Array ◽  
Antenna Arrays ◽  
Spectral Efficiency ◽  
Communication System ◽  
Communication Systems ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Fill Rate ◽  
Content Type

PurposeThe purpose of this paper is to improve energy efficiency and further reduction of side lobe level the algorithm proposed is firework algorithm. In this paper, roused by the eminent swarm conduct of firecrackers, a novel multitude insight calculation called fireworks algorithm (FA) is proposed for work enhancement. The FA is introduced and actualized by mimicking the blast procedure of firecrackers. In the FA, two blast (search) forms are utilized and systems for keeping decent variety of sparkles are likewise all around planned. To approve the presentation of the proposed FA, correlation tests were led on nine benchmark test capacities among the FA, the standard PSO (SPSO) and the clonal PSO (CPSO).Design/methodology/approachThe antenna arrays are used to improve the capacity and spectral efficiency of wireless communication system. The latest communication systems use the antenna array technology to improve the spectral efficiency, fill rate and the energy efficiency of the communication system can be enhanced. One of the most important properties of antenna array is beam pattern. A directional main lobe with low side lobe level (SLL) of the beam pattern will reduce the interference and enhance the quality of communication. The classical methods for reducing the side lobe level are differential evolution algorithm and PSO algorithm. In this paper, roused by the eminent swarm conduct of firecrackers, a novel multitude insight calculation called fireworks algorithm (FA) is proposed for work enhancement. The FA is introduced and actualized by mimicking the blast procedure of firecrackers. In the FA, two blast (search) forms are utilized and systems for keeping decent variety of sparkles are likewise all around planned. To approve the presentation of the proposed FA, correlation tests were led on nine benchmark test capacities among the FA, the standard PSO (SPSO) and the clonal PSO (CPSO). It is demonstrated that the FA plainly beats the SPSO and the CPSO in both enhancement exactness and combination speed. The results convey that the side lobe level is reduced to −34.78dB and fill rate is increased to 78.53.FindingsSamples including 16-element LAAs are conducted to verify the optimization performances of the SLL reductions. Simulation results show that the SLLs can be effectively reduced by FA. Moreover, compared with other benchmark algorithms, fireworks has a better performance in terms of the accuracy, the convergence rate and the stability.Research limitations/implicationsWith the use of algorithms radiation is prone to noise one way or other. Even with any optimizations we cannot expect radiation to be ideal. Power dissipation or electro magnetic interference is bound to happen, but the use of optimization algorithms tries to reduce them to the extent that is possible.Practical implications16-element linear antenna array is available with latest versions of Matlab.Social implicationsThe latest technologies and emerging developments in the field of communication and with exponential growth in users the capacity of communication system has bottlenecks. The antenna arrays are used to improve the capacity and spectral efficiency of wireless communication system. The latest communication systems use the antenna array technology which is to improve the spectral efficiency, fill rate and the energy efficiency of the communication system can be enhanced.Originality/valueBy using FA, the fill rate is increased to 78.53 and the side lobe level is reduced to 35dB, when compared with the bench mark algorithms.

scholarly journals Max–Min Fairness Optimization for D2D Communications Coexisting with Cellular Networks

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1422
Author(s):  
Hoai Giang Nguyen ◽  
Xuan Tung Nguyen ◽  
Van Son Nguyen ◽  
Trinh Van Chien ◽  
Tien Hoa Nguyen ◽  
...  
Keyword(s):  
Spectral Efficiency ◽  
Multiple Access ◽  
Optimization Problem ◽  
Mutual Interference ◽  
D2d Communications ◽  
Power Budget ◽  
Good Service ◽  
Coverage Area ◽  
Channel Condition ◽  
Simulation Results

This paper considers a system consisting of a nonorthogonal multiple access (NOMA)-based device-to-device (D2D) communication system within a cellular network, in which the time and frequency resources are shared by everyone. In particular, D2D groups that constitute different pairs are assigned to the subchannels that the cellular users occupy. A max–min fairness optimization problem with power budget constraints is formulated and solved in this paper to reduce the mutual interference between the cellular users and D2D devices that substantially impacts that with the worst channel condition. For a low computational complexity solution, we propose the use of the bisection method together with the solution of a system of linear equalities. The proposed algorithm can provide uniformly good service to all of the cellular users and D2D devices in the coverage area by utilizing the minimal total transmit power. The simulation results indicate the effectiveness of the proposed algorithm in the improvement of the spectral efficiency of the worst user under the different widely used subchannel assignments and pairing techniques.

scholarly journals Secrecy Analysis and Error Probability of LIS-Aided Communication Systems under Nakagami-m Fading

Entropy ◽  
2021 ◽  
Vol 23 (10) ◽  
pp. 1284
Author(s):  
Ricardo Coelho Ferreira ◽  
Michelle S. P. Facina ◽  
Felipe A. P. de Figueiredo ◽  
Gustavo Fraidenraich ◽  
Eduardo Rodrigues de Lima
Keyword(s):  
Mobile Communications ◽  
Spectral Efficiency ◽  
Communication Systems ◽  
Error Probability ◽  
Signal To Noise Ratio ◽  
Phase Error ◽  
Secrecy Outage Probability ◽  
Single Antenna ◽  
Secrecy Outage ◽  
Von Mises

Large intelligent surfaces (LIS) are a new trend to achieve higher spectral efficiency and signal-to-noise ratio in mobile communications. For this reason, this paper proposes metrics to analyze the performance of systems with multiple antennas aided by LIS and derive the spectral efficiency, secrecy outage probability, and bit error probability in an environment with Nakagami-m distributed fading. In addition to an eavesdropper, there is a single-antenna user, an array of antennas at the transmitter side and the possibility of a direct link between transmitter and receiver. This study assumes that the LIS performs non-ideal phase cancellation leading to a residual phase error that follows a Von Mises distribution, and shows that the resulting channel can be accurately approximated by a Gamma distributed SNR whose parameters are analytically derived. From these formulas, it is possible to evaluate the effect of the strength of the line-of-sight link by varying the Nakagami parameter, m.

Robust Algorithms for DOA Estimation and Adaptive Beamforming in Wireless Mobile Communications

2009 ◽  
pp. 558-564
Author(s):  
R.M. Shubair ◽  
K.O. AlMidfa ◽  
A. Al-Marri ◽  
M. Al-Nuaimi
Keyword(s):  
Mobile Communications ◽  
Antenna Arrays ◽  
Communication Systems ◽  
Smart Antenna ◽  
Doa Estimation ◽  
Adaptive Beamforming ◽  
Lms Algorithm ◽  
Robust Algorithms ◽  
Wireless Mobile Communications ◽  
Wireless Mobile

This paper presents a tool for the modelling, analysis and simulation of direction-of-arrival (DOA) estimation and adaptive beamforming needed in the design of smart antenna arrays for wireless mobile communications. The developed tool implements the Minimum Variance Distortionless Response (MVDR) algorithm for DOA estimation and the Least Mean Squares (LMS) algorithm for adaptive beamforming. Performance of each algorithm is investigated with respect to the variation of a number of parameters that related to the signal environment and sensor array. Results of numerical simulation are useful for the design of smart antennas systems with optimal performance. Hence, the developed simulation tool can be used to improve and accelerate the design of wireless networks. It can also be used for computeraided learning of modern communication systems utilizing smart antenna arrays.

scholarly journals On the Performance of the Multiple Active Antenna Spatial Modulation with 3-Dimensional Constellation

2020 ◽  
Vol 10 (11) ◽  
pp. 3718 ◽  
Author(s):  
Sheriff Murtala ◽  
Tasnim Holoubi ◽  
Nishal Muchena ◽  
Manar Mohaisen ◽  
Kang-Sun Choi
Keyword(s):  
Spectral Efficiency ◽  
Error Probability ◽  
Optimization Problem ◽  
Spatial Modulation ◽  
Active Antenna ◽  
Multi Objective Optimization ◽  
3 Dimensional ◽  
Active Antennas ◽  
Optimal Rotation ◽  
Simulation Results

In spatial modulation (SM), a single signal symbol is transmitted from a given physical antenna, where both the signal symbol and the antenna index carry information. SM with multiple active antennas (MA-SM) transmits several signal symbols from a combination of antennas at each channel use, thereby increasing the spectral efficiency. MA-SM is proposed in combination with a new 3-dimensional constellation, where signal symbols transmitted from a given antenna combination are rotated before transmission. In this paper, we derived an upper-bound on the error probability of the MA-SM as a function of the rotation angles. The search for the optimal rotation angles is modeled as a multi-objective optimization problem. We concluded based on both analytical and simulation results that the 3-dimensional constellation with the optimal angles achieved negligible improvement. Therefore, we do not recommend using the 3-dimensional constellation with the MA-SM system.

A multilayers adaptive ALACO-OFDM for spectral efficiency improvement using PSO algorithm in visible light communication systems

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Aymen Abdalmunam Hameed ◽  
Anuar Mat Safar ◽  
Junita Nordin ◽  
Montadar Abas ◽  
Norizan Nawawi
Keyword(s):  
Visible Light ◽  
Spectral Efficiency ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Electrical Power ◽  
Visible Light Communication ◽  
Pso Algorithm ◽  
Efficiency Improvement ◽  
Frequency Division ◽  
Simulation Results

AbstractIn this paper, we propose a new adaptive layered asymmetrically-clipped optical orthogonal frequency division multiplexing (ALACO-OFDM) technique as a method to improve the spectral efficiency of optical system, especially visible light communication (VLC). Particle swarm optimisation (PSO)-based LACO-OFDM method is used for this purpose and the channel capacities are studied. Simulations using variable layers are carried out to validate the theoretical steps. The simulation results indicate that the ALACO-OFDM technique has significantly improve the spectral efficiency compared to previous techniques such as ACO-OFDM. Moreover, it is shown that channel capacities of different layers are significantly improved when electrical power is increased.

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