scholarly journals Exact secure outage probability performance of uplinkdownlink multiple access network under imperfect CSI

2021 ◽  
Vol 10 (6) ◽  
pp. 3274-3281
Author(s):  
Dinh-Thuan Do ◽  
Minh-Sang Van Nguyen
Keyword(s):  
Outage Probability ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Access Network ◽  
Base Station ◽  
High Signal ◽  
Secrecy Outage Probability ◽  
Factors Affecting ◽  
Secrecy Outage ◽  
The Right

In this paper, we study uplink-downlink non-orthogonal multiple access (NOMA) systems by considering the secure performance at the physical layer. In the considered system model, the base station acts a relay to allow two users at the left side communicate with two users at the right side. By considering imperfect channel state information (CSI), the secure performance need be studied since an eavesdropper wants to overhear signals processed at the downlink. To provide secure performance metric, we derive exact expressions of secrecy outage probability (SOP) and and evaluating the impacts of main parameters on SOP metric. The important finding is that we can achieve the higher secrecy performance at high signal to noise ratio (SNR). Moreover, the numerical results demonstrate that the SOP tends to a constant at high SNR. Finally, our results show that the power allocation factors, target rates are main factors affecting to the secrecy performance of considered uplink-downlink NOMA systems.

scholarly journals Exploiting Uplink NOMA to Improve Sum Secrecy Throughput in IoT Networks

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Zhongwu Xiang ◽  
Weiwei Yang ◽  
Yueming Cai ◽  
Yunpeng Cheng ◽  
Heng Wu ◽  
...  
Keyword(s):  
Outage Probability ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Secrecy Outage Probability ◽  
Benchmark Analysis ◽  
Rate Region ◽  
Device Placement ◽  
Joint Connection ◽  
Secrecy Outage ◽  
The Impact

This paper exploits nonorthogonal multiple access (NOMA) to enhance the uplink secure transmission in Internet of Things (IoT) networks. Considering the different intercept ability of eavesdroppers (Eve), secrecy performances of both strong and weak Eve wiretap scenarios have been investigated. In strong Eve wiretap scenario (SWS), Eve is assumed to be powerful enough to decode message without interference and, in weak Eve wiretap scenario (WWS), Eve is assumed to have significant demodulation capability constraint. The new closed-form expressions of joint connection outage probability (JCOP), joint secrecy outage probability (JSOP), and sum secrecy throughput (SST) are derived in these two scenarios to indicate the impact of parameters, i.e., transmit power, codeword rate, and the placement of devices, on security performance. In order to demonstrate the superiority of NOMA, we also investigate the secrecy performance of orthogonal multiple access (OMA) system as a benchmark. Analysis results show that the performance in WWS is always better than that in SWS and, in low signal-to-noise ratio (SNR) or high codeword rate region, the performances of these two scenarios are close. In addition, we present the condition that NOMA outperforms OMA in terms of SST. Moreover, the placements of devices are significant to the SST performance of NOMA system. The suboptimal device placement scheme has been designed to maximize SST. Analysis results demonstrate that when Eve is far away from legal users, the suboptimal results tend to optimal.

scholarly journals On Secrecy Outage Probability for Downlink NOMA Systems With Relay-Antenna Selection

2021 ◽  
Author(s):  
Shu Xu ◽  
Chen Liu ◽  
Hong Wang ◽  
Mujun Qian ◽  
Wenfeng Sun
Keyword(s):  
Outage Probability ◽  
Multiple Access ◽  
Antenna Selection ◽  
Maximal Ratio Combining ◽  
Selection Combining ◽  
Secrecy Outage Probability ◽  
Channel State ◽  
Secrecy Outage ◽  
Secure Transmission ◽  
Theoretical Results

Abstract Secure transmission is essential for future non-orthogonal multiple access (NOMA) system. This paper investigates relay-antenna selection (RAS) to enhance physical-layer security (PLS) of cooperative NOMA system in the presence of an eavesdropper, where multiple antennas are deployed at the relays, the users, and the eavesdropper. In order to reduce expense on radio frequency (RF) chains, selection combining (SC) is employed at both the relays and the users, whilst the eavesdropper employs either maximal-ratio combining (MRC) or selection combining (SC) to process the received signals. Under the condition that the channel state information (CSI) of the eavesdropping channel is available or unavailable, two e↵ective relay-antenna selection schemes are proposed. Additionally, the closed-form expressions of secrecy outage probability (SOP) are derived for the proposed relay-antenna selection schemes. In order to gain more deep insights on the derived results, the asymptotic performance of the derived SOP is analyzed. In simulations, it is demonstrated that the theoretical results match well with the simulation results and the SOP of the proposed schemes is less than that of the conventional orthogonal multiple access (OMA) scheme obviously.

scholarly journals Analysis and Design of SCMA-Based Hybrid Unicast-Multicast Relay-Assisted Networks

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 329 ◽  
Author(s):  
Yibo Zhang ◽  
Xiaoxiang Wang ◽  
Dongyu Wang ◽  
Yufang Zhang ◽  
Yanwen Lan
Keyword(s):  
Outage Probability ◽  
Cooperative Diversity ◽  
Signal To Noise Ratio ◽  
Base Station ◽  
Cooperative Transmission ◽  
High Signal ◽  
Transmission Scheme ◽  
Two Stage ◽  
Analysis And Design ◽  
Relay Location

This paper studies a multi-user network model based on sparse code multiple access (SCMA), where both unicast and multicast services are considered. In the direct transmission scheme, the communication between the base station (BS) and the users is completed with one stage, in which the relay is inexistent. In the two-stage cooperative transmission scheme, any number of relays are placed to improve the reliability of wireless communication system. The BS broadcasts the requested message to users and relays in the first stage, and the successful relays forward the message to unsuccessful users in the second stage. To characterize the performance of these two schemes, we derive the exact and approximate expressions of average outage probability. Furthermore, to take full advantage of the cooperative diversity, an optimal power allocation and relay location strategy in the high signal-to-noise ratio (SNR) regime is studied. The outage probability reaches the minimum value when the first stage occupies half of the total energy consumed. Simulation and analysis results are presented to demonstrate the performance of these two schemes. The results show that the two-stage cooperative scheme effectively reduce the average outage probability in SCMA network, especially in the high SNR region.

scholarly journals On the Performance Balancing for Uplink NOMA Systems

2020 ◽  
Vol 13 (6) ◽  
pp. 454-459
Author(s):  
Nam-Soo Kim ◽  
Keyword(s):  
Outage Probability ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Base Station ◽  
Cellular Systems ◽  
Mobile Cellular ◽  
Noise Ratio ◽  
Outage Probabilities ◽  
Error Floors

Outage probability and capacity are the representative performance measures for the quality of service (QoS) in mobile cellular systems. Recently, power back-off scheme is proposed in uplink non-orthogonal multiple access (NOMA) systems. The power back-off scheme improves the performance of a near user, however, decreases that of a far user. In comparison, the scheme indicates the error floors with an outage probability of 2.4×〖10〗^(-1) and 9.1×〖10〗^(-2) with power back-off 5 dB and 10 dB, respectively under the specified condition. To address these drawbacks, we propose an equal average signal-to–interference plus noise ratio (SINR) scheme that derives the same average SINR from active users at the base station (BS) in uplink non-orthogonal multiple access (NOMA) systems. Numerical results show that required signal-to-noise ratio (SNR) for the outage probability of 1×〖10〗^(-3) of the near and far users are close enough within 1 dB, which means an outage balance between two users. And it is noticed that the outage probabilities in the proposed scheme decrease as the increase of the received SNR without error floors. Also, different from the power back-off scheme, we noticed that the capacities of the two users in the proposed scheme are coincident and increase with SNR. The outage probabilities and ergodic capacity of the near and far users are derived in closed-form expressions. The analytical results are conformed by Monte Carlo simulation.

scholarly journals Secrecy Performance Analysis of Half/Full Duplex AF/DF Relaying in NOMA Systems Over κ - μ Fading Channels

2021 ◽  
Author(s):  
Nesrine Zaghdoud ◽  
Adel Ben Mnaouer ◽  
Hatem Boujemaa ◽  
Farid Touati
Keyword(s):  
Fading Channels ◽  
Signal To Noise Ratio ◽  
Multipath Fading ◽  
Full Duplex ◽  
High Signal ◽  
Secrecy Outage Probability ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Special Cases ◽  
Secrecy Outage

Abstract Although the progress in understanding 5G and beyond techniques such as Non-Orthogonal Multiple Access (NOMA) and full-duplex techniques has been overwhelming, still analyzing the security aspects of such systems under different scenarios and settings is an important concern that needs further exploration. In particular, when considering fading in wiretap channels and scenarios, achieving secrecy has posed many challenges. In this context, we propose to study the physical layer security (PLS) of cooperative NOMA (C-NOMA) system using the general fading distribution κ - μ. This distribution facilitates mainly the effect of light-of-sight as well as multipath fading. It also includes multiple distributions as special cases like: Rayleigh, Rice, Nakagami-m which help to understand the comportment of C-NOMA systems under different fading parameters. The use of Half-Duplex and Full-Duplex communication is also investigated for both Amplify-and-forward (AF) and Decode-and-Forward (DF) relaying protocols. To characterize the secrecy performance of the proposed C-NOMA systems, closed form expressions of the Secrecy Outage Probability (SOP) and the Strictly Positive Secrcey Capacity (SPSC) metrics for the strong and weak users are given for high signal-to-noise ratio (SNR) due to the intractable nature of the exact expressions. Based on the analytical analysis, numerical and simulation results are given under different network parameters.

scholarly journals Security performance analysis for power domain NOMA employing in cognitive radio networks

2020 ◽  
Vol 9 (3) ◽  
pp. 1046-1054
Author(s):  
Thi-Anh Hoang ◽  
Chi-Bao Le ◽  
Dinh-Thuan Do
Keyword(s):  
Cognitive Radio ◽  
Multiple Access ◽  
Base Station ◽  
Cognitive Networks ◽  
Secrecy Outage Probability ◽  
Security Threat ◽  
Performance Improvements ◽  
Legitimate User ◽  
Power Domain ◽  
Secrecy Outage

The power domain non-orthogonal multiple access (NOMA) technique introduces one of the fundamental characteristics and it exhibits the possibility of users to decode the messages of the other paired users on the same resources. In cognitive radio inspired NOMA (CR-NOMA), the base station (BS) has to serve untrusted users or users with different security clearance. This phenomenon raises a security threat particularly in such CR-NOMA. This paper develops a tractable analysis framework to evaluate the security performance of cooperative non-orthogonal multiple access (NOMA) in cognitive networks, where relay is able to serve two far NOMA users in the presence of external eavesdropper. In particular, we study the secrecy outage probability in a two-user NOMA system. This situation happens in practical the BS is pairing a legitimate user with another untrusted user. Main reason is that the non-uniform distribution in terms of trusted and untrusted users in the cell. By performing numerical results demonstrate the performance improvements of the proposed NOMA scheme in comparison to that of several situations in terms of different parameters. Furthermore, the security performance of NOMA is shown to verify the derived expressions.

scholarly journals Secure outage probability of cognitive radio network relying non-orthogonal multiple access scheme

2021 ◽  
Vol 10 (2) ◽  
pp. 828-836
Author(s):  
Chi-Bao Le ◽  
Dinh-Thuan Do
Keyword(s):  
Outage Probability ◽  
Multiple Access ◽  
Cognitive Radio Network ◽  
Signal To Noise Ratio ◽  
Base Station ◽  
Secondary Source ◽  
Radio Network ◽  
Secondary Network ◽  
Access Scheme ◽  
The Internet Of Things

This paper studies the secondary network relying relay selection to transmit signal from the secondary source (base station) to two destinations. Especially, two destinations are required non-orthogonal multiple access (NOMA) scheme and it benefits to implementation of the Internet of Things (IoT) systems. However, eavesdropper over-hears signal related link from selected relay to destination. This paper measure secure performance via metric, namely secure outage probability (SOP). In particular, signal to noise ratio (SNR) criterion is used to evalute SOP to provide reliable transmission to the terminal node. Main results indicates that the considered scheme provides performance gap among two signals at destination. The exactness of derived expressions is confirmed via numerical simulation.

scholarly journals On the Performance of Security-Based Nonorthogonal Multiple Access in Coordinated Multipoint Networks

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Yue Tian ◽  
Xianling Wang ◽  
Zhanwei Wang
Keyword(s):  
Outage Probability ◽  
Physical Layer Security ◽  
Multiple Access ◽  
Physical Layer ◽  
Secrecy Outage Probability ◽  
Coordinated Multipoint ◽  
Security Issues ◽  
Sum Rate ◽  
Secrecy Outage

The conventional nonorthogonal multiple access (NOMA) strategy has secrecy challenge in coordinated multipoint (CoMP) networks. Under the secrecy considerations, this paper focuses on the security-based NOMA system, which aims to improve the physical layer security issues of conventional NOMA in the coordinated multipoint (NOMA-CoMP) networks. The secrecy performance of S-NOMA in CoMP, that is, the secrecy sum-rate and the secrecy outage probability, is analysed. In contrast to the conventional NOMA (C-NOMA), the results show that the proposed S-NOMA outperforms C-NOMA in terms of the secrecy outage probability and security-based effective sum-rate.

scholarly journals Secure Transmission for Simultaneous Wireless Information and Power Transfer in AF Untrusted Relay Networks

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 76 ◽  
Author(s):  
Hui Shi ◽  
Weiwei Yang ◽  
Dechuan Chen ◽  
Yunpeng Luo ◽  
Yueming Cai
Keyword(s):  
Outage Probability ◽  
Antenna Selection ◽  
Signal To Noise Ratio ◽  
Relay Networks ◽  
Optimal Number ◽  
Maximal Ratio Combining ◽  
High Signal ◽  
Secrecy Outage Probability ◽  
Transmit Antenna Selection ◽  
Untrusted Relay

This paper investigates secure communications of energy harvesting untrusted relay networks, where the destination assists jamming signal to prevent the untrusted relay from eavesdropping and to improve the forwarding ability of the energy constrained relay. Firstly, the source and the destination transmit the signals to the relay with maximal ratio transmission (MRT) technique or transmit antenna selection (TAS) technique. Then, the destination utilizes maximal ratio combining (MRC) technique or receive antenna selection (RAS) technique to receive the forwarded information. Therefore, four transmission and reception schemes are considered. For each scheme, the closed-form expressions of the secrecy outage probability (SOP) and the connection outage probability (COP) are derived. Besides, the effective secrecy throughput (EST) metric is analyzed to achieve a good tradeoff between security and reliability. In addition, the asymptotic performance of EST is also considered at the high signal-to-noise ratio (SNR). Finally, simulation results illustrate that: (1) the EST of the system with MRT and MRC scheme are superior to other schemes, however, in the high SNR regime, the EST of the system with MRT scheme is inferior to TAS; and (2) for the source node, there exists an optimal number of antennas to maximize the EST of the proposed schemes.

scholarly journals Performance Analysis of Cooperative NOMA Networks with Imperfect CSI over Nakagami-m Fading Channels

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 424 ◽  
Author(s):  
Xianli Gong ◽  
Xinwei Yue ◽  
Feng Liu
Keyword(s):  
Outage Probability ◽  
Fading Channels ◽  
Multiple Access ◽  
Base Station ◽  
High Signal ◽  
Direct Link ◽  
Decode And Forward ◽  
Estimation Errors ◽  
Channel Estimation Errors ◽  
Outage Performance

In this paper, we investigate a downlink cooperative non-orthogonal multiple access (NOMA) network with decode-and-forward relaying, where two scenarios of user relaying with direct link and user relaying without direct link are discussed in detail. More particularly, the performance of cooperative NOMA system under the assumption of imperfect channel state information (ipCSI) is studied over Nakagami-m fading channels. To evaluate the outage performance of the above discussed two scenarios, the closed-form expressions of outage probability for a pair of users are derived carefully. The diversity orders of users are achieved in the high signal-to-noise region. An error floor appears in the outage probability owing to the existence of channel estimation errors under ipCSI conditions. Simulation results verify the validity of our analysis and show that: (1) NOMA is superior to conventional orthogonal multiple access; (2) The best user relaying location for cooperative NOMA networks should be near to the base station; and (3) The outage performance of distant user with direct link significantly outperforms distant user without direct link by comparing the two scenarios.

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