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 Robust Secure Beamforming Design for Cooperative Cognitive Radio Nonorthogonal Multiple Access Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Quanzhong Li ◽  
Sai Zhao
Keyword(s):  
Cognitive Radio ◽  
Secure Communication ◽  
Multiple Access ◽  
Spectrum Efficiency ◽  
Maximization Problem ◽  
Artificial Noise ◽  
Practical Case ◽  
Secrecy Rate ◽  
Worst Case ◽  
Rank One

By the integration of cooperative cognitive radio (CR) and nonorthogonal multiple access (NOMA), cooperative CR NOMA networks can improve the spectrum efficiency of wireless networks significantly. Due to the openness and exposure of wireless signals, secure communication is an important issue for cooperative CR NOMA networks. In this paper, we investigate the physical layer security design for cooperative CR NOMA networks. Our objective is to achieve maximum secrecy rate of the secondary user by designing optimal beamformers and artificial noise covariance matrix at the multiantenna secondary transmitter under the quality-of-service at the primary user and the transmit power constraint at the secondary transmitter. We consider the practical case that the channel state information (CSI) of the eavesdropper is imperfect, and we model the imperfect CSI by the worst-case model. We show that the robust secrecy rate maximization problem can be transformed to a series of semidefinite programmings based on S-procedure and rank-one relaxation. We also propose an effective method to recover the optimal rank-one solution. Simulations are provided to show the effectiveness of our proposed robust secure algorithm with comparison to the nonrobust secure design and traditional orthogonal multiple access schemes.

scholarly journals Throughput and Outage Probability Analysis for Cognitive Radio-Non-Orthogonal Multiple Access in Uplink and Downlink Scenarios

2020 ◽  
Vol 7 (4) ◽  
pp. 659-666
Author(s):  
H.T. Madan ◽  
Prabhugoud I. Basarkod
Keyword(s):  
Cognitive Radio ◽  
Outage Probability ◽  
Power Allocation ◽  
Cognitive Radio Networks ◽  
Multiple Access ◽  
Radio Networks ◽  
Spectrum Efficiency ◽  
Secondary Users ◽  
Power Domain ◽  
The Impact

Non orthogonal multiple access (NOMA) in cognitive radio (CR) network has been recognized as potential solution to support the simultaneous transmission of both primary and secondary users. In addition, CR-NOMA can also be used to serve multiple secondary networks in overlay cognitive radio networks. The aim of our work is to increase the secondary user’s throughput without compromising in QoS requirements of the primary users. Our presented work analyses the performance of power domain NOMA in cognitive radio networks for both uplink and downlink scenarios. The primary aspect of the work is to investigate the impact of power allocation on spectrum efficiency and fairness performance of CR-NOMA. Objective function is to maximize the overall throughput under the QOS constraints of the users. We have derived closed form expressions for optimized power allocation coefficient(α) for CR-NOMA uplink and downlink communications. Parameters causing the channel outage, have been examined and conditions for outage probability is derived for CR-NOMA communication. Finally, we have presented the simulation results to validate the mathematical models that are developed for power allocation coefficient and outage probability.

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 5G cognitive radio system design with new algorithm asynchronous spectrum sensing

2021 ◽  
Vol 10 (4) ◽  
pp. 2046-2054
Author(s):  
Mohammed Mehdi Saleh ◽  
Ahmed A. Abbas ◽  
Ahmed Hammoodi
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Energy Detection ◽  
Primary User ◽  
Spectrum Access ◽  
Secondary Users ◽  
Radio System ◽  
Wireless Applications ◽  
Fifth Generation ◽  
Time Required

Due to the rapid increase in wireless applications and the number of users, spectrum scarcity, energy consumption and latency issues will emerge, notably in the fifth generation (5G) system. Cognitive radio (CR) has emerged as the primary technology to address these challenges, allowing opportunist spectrum access as well as the ability to analyze, observe, and learn how to respond to environmental 5G conditions. The CR has the ability to sense the spectrum and detect empty bands in order to use underutilized frequency bands without causing unwanted interference with legacy networks. In this paper, we presented a spectrum sensing algorithm based on energy detection that allows secondary user SU to transmit asynchronously with primary user PU without causing harmful interference. This algorithm reduced the sensing time required to scan the whole frequency band by dividing it into n sub-bands that are all scanned at the same time. Also, this algorithm allows cognitive radio networks (CRN) nodes to select their operating band without requiring cooperation with licensed users. According to the BER, secondary users have better performance compared with primary users.

Development of mathematical model for multi-user coded-cooperation based cognitive radio system and its outage probability analysis

2021 ◽  
Author(s):  
Garima Singh ◽  
Gurjit Kaur
Keyword(s):  
Mathematical Model ◽  
Cognitive Radio ◽  
Outage Probability ◽  
Utilization Efficiency ◽  
Spectrum Efficiency ◽  
Spectrum Utilization ◽  
Radio System ◽  
Cognitive Radio System ◽  
Temperature Constraint ◽  
Coded Cooperation

Abstract In this paper, single and multi-user coded-cooperation based cognitive radio system is developed by designing its mathematical model where both source and relay will communicate to a single destination with the help of each other. Then all possible multi-user scenarios are developed and their end-to-end outage probability (Pout) is calculated for underlay mode of cognitive radio. The performance of the system is analyzed in the form of channel gain and interference temperature constraint for Rayleigh fading channel. The proposed system concludes that the coded cooperation with cognitive radio outperform the available techniques in the form of bandwidth, diversity, spectrum utilization efficiency and also improves the quality of communication. Furthermore, the theoretical analysis of the outage probability for both system models is validated by asymptotic analysis. The proposed system can set as a standard for all those cognitive radio applications which requires better spectrum efficiency even if there is a scarcity of multiple physical antennas.

scholarly journals Energy Efficiency Optimization in Cooperative Spectrum Sensing by NOMA

2018 ◽  
Vol 7 (3.12) ◽  
pp. 1125 ◽  
Author(s):  
Meenakshi Awasthi ◽  
J.Madhav Nigam ◽  
Vijay Kumar
Keyword(s):  
Energy Efficiency ◽  
Cognitive Radio ◽  
Cooperative Spectrum Sensing ◽  
Basic Feature ◽  
Spectrum Efficiency ◽  
Superior Performance ◽  
Secondary Users ◽  
Energy Efficiency Improvement ◽  
5G Systems ◽  
Multiple Primary Users

Energy efficiency improvement is a major point of concern in cooperative scenario of cognitive radio networks, so as to compensate the overhead occurred due to power consumed by multiple numbers of secondary users. Non-orthogonal multiple access (NOMA) is a potential technique to get the higher spectrum efficiency for 5G systems. The basic feature of NOMA is to utilize the same channel, time and code but at different power levels, which results in higher spectrum efficiency (SE). In this article, firstly the cognitive radio (CR) inspired NOMA is generalized by multiple primary users. Then, energy efficiency (EE) is optimized for the proposed system. An efficient algorithm is proposed for the non-convex fractional programming problem. Simulation results show the superior performance over conventional multiple accesstechniques.  

scholarly journals Ranked Sense Multiple Access Control Protocol for Multichannel Cognitive Radio-Based IoT Networks

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1703 ◽  
Author(s):  
Muhammad Shafiq ◽  
Pankaj Singh ◽  
Imran Ashraf ◽  
Maqbool Ahmad ◽  
Amjad Ali ◽  
...  
Keyword(s):  
Cognitive Radio ◽  
Ad Hoc Networks ◽  
Multiple Access ◽  
Ad Hoc ◽  
Markov Chain Model ◽  
Low Cost ◽  
Chain Model ◽  
Secondary Users ◽  
Hoc Networks ◽  
Cr System

The widespread growth of the Internet-of-Things (IoT) and its dependence on the license-exempt Industrial, Scientific, and Medical (ISM) bands have made spectrum resources scarce. IoT can nonetheless get advantage from the Cognitive Radio (CR) technology to resolve the spectrum shortage issue. Since in CR networks the unlicensed Secondary Users (SUs) can exploit the white spaces in licensed channels of Primary Users (PUs) opportunistically. CR ad hoc networks are more useful in IoT due to ease of installation, low cost, and less complexity. However, CR ad hoc networks are prone to the rendezvous issue and hidden primary terminal problem. Moreover, the available channels in the CR system are not identical, PUs’ and SUs’ activities can diversify them as well. In this connection, channel selection by SUs is a complex balancing act since the transmission opportunities are space, frequency and time bounded. In this paper, we hence proposed a new Ranked Sense Multiple Access with Collision Avoidance (RSMA/CA) protocol for multichannel CR-based IoT networks. Our proposed RSMA/CA protocol not only resolves the hidden primary terminal problem but also avoids hidden and exposed terminal problems at the same time by mutual spectrum sensing. We suggest a new channel ranking mechanism to rank the available channels based on the long term qualities of the channels, PUs’ return rate, and SUs’ activities and tailor-made the algorithms in an existing scheme to make the rendezvous process more efficient. We analyze the performance of our proposed RSMA/CA in terms of normalized throughput through the Markov chain model and compared with that of the existing scheme. Simulation results show that our RSMA/CA protocol outperforms the existing scheme due to efficient rendezvous and access mechanisms.

Spectrum Sensing and Throughput Analysis for Cognitive Radio An Overview

2012 ◽  
pp. 203-224
Author(s):  
M. A. Matin ◽  
M Ahmed ◽  
N. Ferdous
Keyword(s):  
Cognitive Radio ◽  
Power Allocation ◽  
Spectrum Sensing ◽  
New Technology ◽  
Spectrum Efficiency ◽  
System Throughput ◽  
Secondary Users ◽  
Primary Users ◽  
Spectrum Scarcity ◽  
Cooperative Relays

Cognitive radio (CR) is a new technology introduced to deal with the issues of spectrum scarcity and underutilization. Since the spectrum is limited, the unlicensed secondary users (CR users) opportunistically access the underutilized spectrum allocated to the licensed primary users (PUs) of the network. This chapter first gives a brief overview on spectrum sensing and its impact on the system throughput in a cognitive radio network. Later, cooperative relays are introduced in the network to improve spectrum efficiency and mitigate interference to PU. A detailed analysis of power allocation is demonstrated where the transmit power of CR is kept within such limit so that it can maintain low interference to PU. This optimal power allocation can achieve high throughput, which is also presented in this chapter.

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