In smart cities, the ubiquitous network connections and high data rate services are provided to afford effective service of real-time monitoring and responses. With the development of the 5G mobile communication technology, the wireless sensor mobile communication networks in the smart city have become a hot issue for academic researches. Due to the openness of wireless channels, the physical layer security of the wireless mobile sensor mobile communication networks in smart city encounters severe challenges. In this paper, based on Wyner's wiretap model, the secrecy performance of the wireless mobile sensor communication networks over 2-Nakagami fading channels is investigated. We derive the exact secure outage probability (SOP) and the probability of strictly positive secrecy capacity expressions for two transmit antenna selection (TAS) schemes. The exact closed-form expressions for the lower bound on the SOP are also derived using the optimal TAS scheme. Then, the system secrecy performance is verified and analyzed by Monte Carlo simulations under different conditions. The simulation results show that the analytical results match perfectly with the Monte Carlo simulation results. Increasing the number of transmit antennas can improve secrecy performance.
In smart cities, the ubiquitous network connections and high data rate services are provided to afford effective service of real-time monitoring and responses. With the development of the 5G mobile communication technology, the wireless sensor mobile communication networks in the smart city have become a hot issue for academic researches. Due to the openness of wireless channels, the physical layer security of the wireless mobile sensor mobile communication networks in smart city encounters severe challenges. In this paper, based on Wyner's wiretap model, the secrecy performance of the wireless mobile sensor communication networks over 2-Nakagami fading channels is investigated. We derive the exact secure outage probability (SOP) and the probability of strictly positive secrecy capacity expressions for two transmit antenna selection (TAS) schemes. The exact closed-form expressions for the lower bound on the SOP are also derived using the optimal TAS scheme. Then, the system secrecy performance is verified and analyzed by Monte Carlo simulations under different conditions. The simulation results show that the analytical results match perfectly with the Monte Carlo simulation results. Increasing the number of transmit antennas can improve secrecy performance.
The Performance of Physical Layer Security over K Fading SIMO Channel
The wireless communication services are developing rapidly, but the vulnerability of its broadcast is often eavesdropped and attacked by an illegal third party, which poses a huge challenge for secure transmission. Traditional upper-layer protocols and tools have inherent loopholes and difficulties in key distribution and management. However physical layer security technology has become an important technology to the assurance of information security by its simple algorithms and better practicability. In this paper, based on the secure performance of single-input multiple-out (SIMO) Wyner's wiretap model over K fading channels, the closed-form expressions for average secrecy capacity (ASC), secure outage probability (SOP) and the probability of strictly positive secrecy capacity (SPSC) are derived. The theoretical analysis and Monte Carlo simulation prove that the results are consistent and feasible, with an important role in restraining illegal interception and attack.
Intrigued by the rapid growth and expand of wireless devices, data security is increasingly playing a significant role in our daily transactions and interactions with different entities. Possible examples, including e-healthcare information and online shopping, are becoming vulnerable due to the intrinsic nature of wireless transmission medium and the widespread open access of wireless links. Traditionally, the communication security is mainly regarded as the tasks at the upper layers of layered protocol stack, security techniques, including personal access control, password protection, and end-to-end encryption, have been widely studied in the open literature. More recently, plenty of research interests have been drawn to the physical layer forms of secrecy. As a new but appealing paradigm at physical layer, physical layer security is based on two pioneering works: (i) Shannon’s information-theoretic formulation and (ii) Wyner’s wiretap formulation. \n \nOn account of the fundamental of physical layer security and the different nature of various wireless network, this dissertation is supposed to further fill the lacking of the existing research outcomes. To be specific, the contributions of this dissertation can be summarized as three-fold:(i) exploration of secrecy metrics to more general fading channels; (ii) characterization a new fading channel model and its reliability and security analysis in digital communication systems; and (iii) investigation of physical layer security over the random multiple-input multiple-output (MIMO) α −μ fading channels. \n \nTaking into account the classic Alice-Bob-Eve wiretap model, the first contribution can be divided into four aspects: (i) we have investigated the secrecy performance over single-input single-output (SISO) α −μ fading channels. The probability of non-zero (PNZ) secrecy capacity and the lower bound of secrecy outage probability (SOP) are derived for the special case when the main channel and wiretap channel undergo the same non-linearity fading parameter, i.e., α. Later on, for the purpose of filling the gap of lacking closed-form expression of SOP in the open literature and extending the obtained results in chapter 2 to the single-input multiple-output (SIMO) α − μ wiretap fading channels, utilizing the fact that the received signal-tonoise ratios (SNRs) at the legitimate receiver and eavesdropper can be approximated as new α −μ distributed random variables (RVs), the SOP metric is therefore derived, and given in terms of the bivariate Fox’s H-function; (ii) the secrecy performance over the Fisher-Snedecor F wiretap fading channels is initially considered. The SOP, PNZ, and ASC are finalized in terms of Meijer’s G-function; (iii) in order to generalize the obtained results over α −μ and Fisher-Snedecor F wiretap fading channels, a more flexible and general fading channel, i.e., Fox’s H-function fading model, are taken into consideration. Both the exact and asymptotic analysis of SOP, PNZ, and average secrecy capacity (ASC), are developed with closed-form expressions; and (iv) finally, motivated by the fact that the mixture gamma (MG) distribution is an appealing tool, which can be used to model the received instantaneous SNRs over wireless fading channels, the secrecy metrics over wiretap fading channels are derived based on the MG approach. \n \nDue to the limited transmission power and communication range, cooperative relays or multi-hop wireless networks are usually regarded as two promising means to address these concerns. Inspired by the obtained results in Chapters 2 and 3, the second main contribution is to propose a novel but simple fading channel model, namely, the cascaded α −μ. This new distribution is advantageous since it encompasses the existing cascaded Rayleigh, cascaded Nakagami-m, and cascaded Weibull with ease. Based on this, both the reliability and secrecy performance of a digital system over cascaded α −μ fading channels are further evaluated. Closed-form expressions of reliability metrics (including amount of fading (AF), outage probability, average channel capacity, and average symbol error probability (ABEP).) and secrecy metrics (including SOP, PNZ, and ASC) are respectively provided. Besides, their asymptotic behaviors are also performed and compared with the exact results. \n \nConsidering the impacts of users’ densities, spatial distribution, and the path-loss exponent on secrecy issue, the third aspect of this thesis is detailed in Chapter 8 as the secrecy investigation of stochastic MIMO system over α −μ wiretap fading channels. Both the stochastic geometry and conventional space-time transmission (STT) scheme are used in the system configuration. The secrecy issue is mathematically evaluated by three metrics, i.e., connection outage, the probability of non-zero secrecy capacity and the ergodic secrecy capacity. Those three metrics are later on derived regarding two ordering scheme, and further compared with Monte-Carlo simulations.
Next-generation wireless communication systems with high user mobility inherit cascaded fading channel models, where the fading effects are more severe than classical channel models including Rayleigh and Nakagami-m. In this study, physical layer secrecy/security performance analysis has been investigated over double Nakagami-m fading channels. While analytic results are derived, the closed-form expression of the probability of positive secrecy capacity is obtained, then the exact secrecy outage probability is obtained in the closed-form. Furthermore, computer simulations are given to verify the analytic results.
The impact of antenna correlation on secrecy performance in wireless communication networks is analyzed. This network consists of a signal antenna at the source, while receiver and eavesdropper are both equipped with multiple antennas, which are correlated in space. We employ maximal-ratio combining (MRC) scheme at the receiver and eavesdropper to combine the received signals. We assume that the main channel and the eavesdropper's channel undergo Nakagami-m fading with the fading parameters mB and mE, respectively. In this paper, we derive new closed-form expressions for the exact secrecy outage probability and the probability of positive secrecy. To verify the analytical results, we provide Monte Carlo simulations at the end.
Physical layer security is an important method to improve the secrecy performance of wireless communication systems. In this paper, we analyze the effect of employing channel correlation to improve security performance in multiple-input multiple-output (MIMO) scenario with antenna selection (AS) scheme. We first derive the analytical expressions of average secrecy capacity (ASC) and secrecy outage probability (SOP) by the first order Marcum Q function. Then, the asymptotic expressions of ASC and SOP in two specific scenarios are further derived. The correctness of analytical and asymptotic expressions is verified by Monte Carlo simulations. The conclusions suggest that the analytical expressions of ASC and SOP are related to the product of transmitting and receiving antennas; increasing the number of antennas is beneficial to ASC and SOP. Besides, when the target rate is set at a low level, strong channel correlation is bad for ASC, but is beneficial to SOP.
Secrecy Analysis of Physical Layer over κ−μ Shadowed Fading Scenarios
In this paper, the secrecy analysis of physical layer when both the main and wiretap channels undergo κ−μ shadowed fading channel is investigated. In particular, the average secrecy capacity (ASC), secure outage probability (SOP), the lower bound of SOP (SOPL), and the probability of strictly positive secrecy capacity (SPSC) are derived by using the classic Wyner's wiretap model. Two different scenarios for the fading parameters, i.e., μ and m which represents the shadowing impact have been studied. These parameters are chosen first as arbitrary numbers, thus the performance metrics are expressed in single infinite series with multivariate Meijer G-function. In the second scenario, both the aforementioned fading parameters are assumed to be integer numbers in order to obtain the derived results in simple exact closed-form analytic mathematically tractable expressions. The numerical results of this analysis are verified via Monte Carlo simulations.