scholarly journals Approximations of the Aggregated Interference Statistics for Outage Analysis in Massive MTC

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5448
Author(s):  
Sergi Liesegang ◽  
Antonio Pascual-Iserte ◽  
Olga Muñoz
Keyword(s):  
Outage Probability ◽  
Closed Form ◽  
Detection Threshold ◽  
Gaussian Kernel ◽  
Closed Form Expression ◽  
Allocation Strategy ◽  
Spatial Beams ◽  
Discrete Nature ◽  
Interference Statistics ◽  
Multiple Resource

This paper presents several analytic closed-form approximations of the aggregated interference statistics within the framework of uplink massive machine-type-communications (mMTC), taking into account the random activity of the sensors. Given its discrete nature and the large number of devices involved, a continuous approximation based on the Gram–Charlier series expansion of a truncated Gaussian kernel is proposed. We use this approximation to derive an analytic closed-form expression for the outage probability, corresponding to the event of the signal-to-interference-and-noise ratio being below a detection threshold. This metric is useful since it can be used for evaluating the performance of mMTC systems. We analyze, as an illustrative application of the previous approximation, a scenario with several multi-antenna collector nodes, each equipped with a set of predefined spatial beams. We consider two setups, namely single- and multiple-resource, in reference to the number of resources that are allocated to each beam. A graph-based approach that minimizes the average outage probability, and that is based on the statistics approximation, is used as allocation strategy. Finally, we describe an access protocol where the resource identifiers are broadcast (distributed) through the beams. Numerical simulations prove the accuracy of the approximations and the benefits of the allocation strategy.

scholarly journals Joint Resource Allocation for SWIPT-Based Two-Way Relay Networks

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6024
Author(s):  
Chunling Peng ◽  
Guozhong Wang ◽  
Fangwei Li ◽  
Huaping Liu
Keyword(s):  
Resource Allocation ◽  
Outage Probability ◽  
Closed Form ◽  
Time Allocation ◽  
Closed Form Solution ◽  
Form Solution ◽  
Closed Form Expression ◽  
Power Splitting ◽  
Decode And Forward ◽  
Joint Resource Allocation

This paper considers simultaneous wireless information and power transfer (SWIPT) in a decode-and-forward two-way relay (DF-TWR) network, where a power splitting protocol is employed at the relay for energy harvesting. The goal is to jointly optimize power allocation (PA) at the source nodes, power splitting (PS) at the relay node, and time allocation (TA) of each duration to minimize the system outage probability. In particular, we propose a static joint resource allocation (JRA) scheme and a dynamic JRA scheme with statistical channel properties and instantaneous channel characteristics, respectively. With the derived closed-form expression of the outage probability, a successive alternating optimization algorithm is proposed to tackle the static JRA problem. For the dynamic JRA scheme, a suboptimal closed-form solution is derived based on a multistep optimization and relaxation method. We present a comprehensive set of simulation results to evaluate the proposed schemes and compare their performances with those of existing resource allocation schemes.

scholarly journals Performance Analysis and Optimization of RIS-Assisted Networks in Nakagami-m Environment

2021 ◽  
Author(s):  
Monjed H. Samuh ◽  
Ahmed H. Abd El-Malek ◽  
Keyword(s):  
Outage Probability ◽  
Closed Form ◽  
Signal To Noise Ratio ◽  
Closed Form Expression ◽  
High Signal ◽  
Optimum Number ◽  
Diversity Order ◽  
Symbol Error Probability ◽  
Fading Parameter ◽  
Performance Results

Abstract This work studies and optimizes the performance of reconfigurable intelligent surface (RIS)-aided networks in Nakagami- m fading environment. First, accurate closed-form approximations for the channel distributions are derived. Then, closed-form formulas for the system outage probability, average symbol error probability (ASEP), and the channel capacity are obtained. Furthermore, we provide three different optimization approaches for finding the optimum number of reflecting elements to achieve a target outage probability. At the high signal-to-noise ratio (SNR) regime, a closed-form expression for the asymptotic outage probability is obtained to give more insights into the system performance. Results show that the considered system can achieve a diversity order of, where a is a function of the Nakagami- m fading parameter m and the number of reflecting elements N . Moreover, findings show that m is more influential on the diversity order than N . Finally, the achieved expressions are applicable to non-integer values of m and any number of meta-surface elements N .

scholarly journals Exploiting Opportunistic Scheduling for Physical-Layer Security in Multitwo User NOMA Networks

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Kyusung Shim ◽  
Beongku An
Keyword(s):  
Outage Probability ◽  
Closed Form ◽  
Base Station ◽  
Closed Form Expression ◽  
Opportunistic Scheduling ◽  
Secrecy Outage Probability ◽  
Form Expression ◽  
Selection Scheme ◽  
Optimal Values ◽  
Secrecy Outage

In this paper, we address the opportunistic scheduling in multitwo user NOMA system consisting of one base station, multinear user, multifar user, and one eavesdropper. To improve the secrecy performance, we propose the users selection scheme, called best-secure-near-user best-secure-far-user (BSNBSF) scheme. The BSNBSF scheme aims to select the best near-far user pair, whose data transmission is the most robust against the overhearing of an eavesdropper. In order to facilitate the performance analysis of the BSNBSF scheme in terms of secrecy outage performance, we derive the exact closed-form expression for secrecy outage probability (SOP) of the selected near user and the tight approximated closed-form expression for SOP of the selected far user, respectively. Additionally, we propose the descent-based search method to find the optimal values of the power allocation coefficients that can minimize the total secrecy outage probability (TSOP). The developed analyses are corroborated through Monte Carlo simulation. Comparisons with the random-near-user random-far-user (RNRF) scheme are performed and show that the proposed scheme significantly improves the secrecy performance.

scholarly journals Cooperative Jammer Selection for Secrecy Improvement in Cognitive Internet of Things

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4257 ◽  
Author(s):  
Ping Xie ◽  
Ling Xing ◽  
Honghai Wu ◽  
Jung Seo ◽  
Ilsun You
Keyword(s):  
Internet Of Things ◽  
Outage Probability ◽  
Closed Form ◽  
Smart Homes ◽  
Primary User ◽  
Closed Form Expression ◽  
Artificial Noise ◽  
Transmission Protocol ◽  
Security Model ◽  
Intercept Probability

Smart homes can improve the quality of life and be implemented by Internet of Things (IoT) technologies. However, security is a very important issue in smart homes. For this reason, we propose a secrecy transmission protocol for primary user (PU) by selecting friendly jammer in cognitive IoT model. In particular, a secondary transmitter (ST) is selected to transmit secondary signals by the PU’s frequency spectrum, while another ST is chosen to transmit artificial noise to protect the transmission confidentiality of the PU against eavesdropping. Moreover, two selection schemes are presented to confirm the former and the latter ST, and the goal is to optimize the secondary transmission performance and the primary security performance, respectively. For the non-security model and the proposed protocol, we derive the closed-form expressions of the intercept probability and the outage probability for the PU. We also obtain the closed-form expression of outage probability for the secondary user. The numerical results show that the security performance of the PU is significantly enhanced in our protocol compared to the non-security model. In addition, the outage performance of the secondary users is also improved in high secondary transmit SNR region.

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