scholarly journals Secrecy-Oriented Optimization of Sparse Code Multiple Access for Simultaneous Wireless Information and Power Transfer in 6G Aerial Access Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jingmin Zhang ◽  
Xiaokui Yue ◽  
Xuan Li ◽  
Haofei Zhang ◽  
Tao Ni ◽  
...  
Keyword(s):  
Multiple Access ◽  
Optimization Methods ◽  
Access Networks ◽  
Spectrum Efficiency ◽  
Sparse Code ◽  
Power Splitting ◽  
Power Transfer ◽  
Sixth Generation ◽  
Successive Convex Approximation ◽  
Iot Devices

This article focuses on the simultaneous wireless information and power transfer (SWIPT) systems, which provide both the power supply and the communications for Internet-of-Things (IoT) devices in the sixth-generation (6G) network. Due to the extremely stringent requirements on reliability, speed, and security in the 6G network, aerial access networks (AANs) are deployed to extend the coverage of wireless communications and guarantee robustness. Moreover, sparse code multiple access (SCMA) is implemented on the SWIPT system to further promote the spectrum efficiency. To improve the speed and security of SWIPT systems in 6G AANs, we have developed an optimization algorithm of SCMA to maximize the secrecy sum rate (SSR). Specifically, a power-splitting (PS) strategy is applied by each user to coordinate its energy harvesting and information decoding. Hence, the SSR maximization problems in the SCMA system are formulated in terms of the PS and resource allocation, under the constraints on the minimum rates and minimum harvested energy of individual users. Then, a successive convex approximation method is introduced to transform the nonconvex problems to the convex ones, which are then solved by an iterative algorithm. In addition, we investigate the SSR performance of the SCMA system supported by our optimization methods, when the impacts from different perspectives are considered. Our studies and simulation results show that the SCMA system supported by our proposed optimization algorithms significantly outperforms the legacy system with uniform power allocation and fixed PS.

scholarly journals Joint Beamforming and Artificial Noise Optimization for Secure Transmissions in MISO-NOMA Cognitive Radio System with SWIPT

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1948
Author(s):  
Carla E. Garcia ◽  
Mario R. Camana ◽  
Insoo Koo
Keyword(s):  
Cognitive Radio ◽  
Mobile Networks ◽  
Multiple Access ◽  
Relaxation Method ◽  
Spectrum Efficiency ◽  
Artificial Noise ◽  
Power Splitting ◽  
Secondary Users ◽  
Space Division Multiple Access ◽  
Radio System

The integration of non-orthogonal multiple access (NOMA) in cognitive radio (CR) networks has demonstrated how to enhance spectrum efficiency and achieve massive connectivity for future mobile networks. However, security is still a challenging issue due to the wireless transmission environment and the broadcast nature of NOMA. Thus, in this paper, we investigate a beamforming design with artificial noise (AN) to improve the security of a multi-user downlink, multiple-input single-output (MISO) NOMA-CR network with simultaneous wireless information and power transfer (SWIPT). To further support power-limited, battery-driven devices, energy-harvesting (EH) users are involved in the proposed network. Specifically, we investigate the optimal AN, power-splitting ratios, and transmission beamforming vectors for secondary users and EH users in order to minimize the transmission power of the secondary network, subject to the following constraints: a minimum signal-to-interference-plus-noise ratio at the secondary users, minimum harvested energy by secondary users and EH users, maximum power at the secondary transmitter, and maximum permissible interference with licensed users. The proposed solution for the challenging non-convex optimization problem is based on the semidefinite relaxation method. Numerical results show that the proposed scheme outperforms the conventional scheme without AN, the zero-forcing-based scheme and the space-division multiple-access-based method.

scholarly journals Sparse code multiple access on the generalized frequency division multiplexing

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Guilherme P. Aquino ◽  
Luciano L. Mendes
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
Physical Layer ◽  
Spectrum Efficiency ◽  
Sparse Code ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Time Frequency ◽  
Performance Loss

Abstract Recent advances in the communication systems culminated in a new class of multiple access schemes, named non-orthogonal multiple access (NOMA), where the main goal is to increase the spectrum efficiency by overlapping data from different users in a single time-frequency resource used by the physical layer. NOMA receivers can resolve the interference among data symbols from different users, increasing the overall system spectrum efficiency without introducing symbol error rate (SER) performance loss, which makes this class of multiple access techniques interesting for future mobile communication systems. This paper analyzes one promising NOMA technique, called sparse code multiple access (SCMA), where C users can share U<C time-frequency resources from the physical layer. Initially, the SCMA and orthogonal frequency division multiplexing (OFDM) integration is considered, defining a benchmark for the overall SER performance for the multiple access technique. Furthermore, this paper proposes the SCMA and generalized frequency division multiplexing (GFDM) integration. Since GFDM is a highly flexible non-orthogonal waveform that can mimic several other waveforms as corner cases, it is an interesting candidate for future wireless communication systems. This paper proposes two approaches for combining SCMA and GFDM. The first one combines a soft equalizer, called block expectation propagation (BEP), and a multi-user detection (MUD) scheme based on the sum-product algorithm (SPA). This approach achieves the best SER performance, but with the significant increment of the complexity at the receiver. In the second approach, BEP is integrated with a simplified MUD, which is an original contribution of this paper, aiming for reducing the receiver’s complexity at the cost of SER performance loss. The solutions proposed in this paper show that SCMA-GFDM can be an interesting solution for future mobile networks.

Examination of the fifth-generation vehicular simultaneous wireless information and power transfer cooperative non-orthogonal multiple access network in military scenarios considering time-varying and imperfect channel state information conditions

2021 ◽  
pp. 154851292110330
Author(s):  
Sharnil Pandya ◽  
Patteti Krishna ◽  
Ravi Shankar ◽  
Ankur Singh Bist
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Multiple Access ◽  
Ad Hoc ◽  
Access Network ◽  
Power Splitting ◽  
Power Transfer ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Fifth Generation

In a defense scenario, the communicating nodes are mobile and, due to this, the fading channel links become time selective in nature. Non-orthogonal multiple access (NOMA) is a promising technique in modern wireless communication systems, and it is employed in a variety of defense ad hoc wireless communication scenarios where nodes are mobile and it is difficult to estimate the channel coefficients perfectly. NOMA contributes to increased spectral efficiency (SE), firstly by enabling fifth-generation new radio deployment in the 3.5 GHz frequency range, and secondly by employing a simultaneous wireless information and power transfer (SWIPT) time switching and power splitting-based cooperative NOMA (C-NOMA) network where simple radio frequency circuitry is used for energy harvesting. NOMA together with the selective decode-and-forward (S-DF) protocol will increase the SE and energy efficiency simultaneously. The outage probability performance is evaluated for various values of the fading severity parameter and node velocity forming the channel error. It is significant to note that digital S-DF-based SWIPT C-NOMA performs much better than an analog amplify-and-forward-based C-NOMA SWIPT system.

scholarly journals Implement of multiple access technique by wireless power transfer and relaying network

2021 ◽  
Vol 10 (2) ◽  
pp. 793-800
Author(s):  
Anh-Tu Le ◽  
Dinh-Thuan Do
Keyword(s):  
Multiple Access ◽  
Performance Metrics ◽  
Signal To Noise Ratio ◽  
Wireless Power Transfer ◽  
Base Station ◽  
Power Splitting ◽  
Power Transfer ◽  
Wireless Power ◽  
Amplify And Forward ◽  
Decode And Forward

In this paper, we investigate non-orthogonal multiple access (NOMA) network relying on wireless power transfer to prolong lifetime. The base station (BS) sends common signals to the relay with two functions (energy harvesting (EH) and signal processing) to further serve two NOMA users in downlink. Performance gap exists since different power allocation factor assigned from power splitting protocol adopted at the relay and such relay employs both amplify-and-forward (AF) and decode-and-forward schemes. To provide performance metrics, we prove formulas of the outage probability which is a function of transmit signal to noise ratio. Simulation results indicate specific parameters to adjust system performance of two user in the considered EH-NOMA system. This finding is important recommendation to design EH-NOMA which shows particular outage performance at required target rates.

scholarly journals Outage performance analysis of non-orthogonal multiple access systems with RF energy harvesting

2021 ◽  
Vol 11 (5) ◽  
pp. 4135
Author(s):  
Hoang Thien Van ◽  
Vo Tien Anh ◽  
Danh Hong Le ◽  
Ma Quoc Phu ◽  
Hoang-Sy Nguyen
Keyword(s):  
Energy Harvesting ◽  
Fading Channels ◽  
Multiple Access ◽  
Power Splitting ◽  
Decode And Forward ◽  
Fifth Generation ◽  
Half Duplex ◽  
Iot Devices ◽  
Indoor Scenarios ◽  
Log Normal

Non-orthogonal multiple access (NOMA) has drawn enormous attention from the research community as a promising technology for future wireless communications with increasing demands of capacity and throughput. Especially, in the light of fifth-generation (5G) communication where multiple internet-of-things (IoT) devices are connected, the application of NOMA to indoor wireless networks has become more interesting to study. In view of this, we investigate the NOMA technique in energy harvesting (EH) half-duplex (HD) decode-and-forward (DF) power-splitting relaying (PSR) networks over indoor scenarios which are characterized by log-normal fading channels. The system performance of such networks is evaluated in terms of outage probability (OP) and total throughput for delay-limited transmission mode whose expressions are derived herein. In general, we can see in details how different system parameters affect such networks thanks to the results from Monte Carlo simulations. For illustrating the accuracy of our analytical results, we plot them along with the theoretical ones for comparison.

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