With the assistance of relays, cooperative communication provides the benefits of spatial diversity to improves the system performance. It could be prospective for the application of wireless networks. The issue of security is highly requested for personal privacy in the internet. With applying this cooperative system to internet service, security is critically requested. Usually, in the higher layer networks, it adopts an encryption to approach the security request. However, a complex encryption spends a lot of computer resource. It is not practical for Internet of things (IoT) application which has a limited computing resource. Shannon perfect secrecy illustrates the secure communication could be implemented on the physical layer. Assuming the relays in the system is the eavesdroppers, this paper provides the secrecy analysis for the cooperative system and gives a theoretical solution. With an appropriate assignment of relay, the results show that the cooperative system could provide a secure communication if the number of available relays is larger than that of eavesdroppers. A proper choosing the relays to transmit the information could be the important issue in the cooperative communication system.
With the assistance of relays, cooperative communication provides the benefits of spatial diversity to improves the system performance. It could be prospective for the application of wireless networks. The issue of security is highly requested for personal privacy in the internet. With applying this cooperative system to internet service, security is critically requested. Usually, in the higher layer networks, it adopts an encryption to approach the security request. However, a complex encryption spends a lot of computer resource. It is not practical for Internet of things (IoT) application which has a limited computing resource. Shannon perfect secrecy illustrates the secure communication could be implemented on the physical layer. Assuming the relays in the system is the eavesdroppers, this paper provides the secrecy analysis for the cooperative system and gives a theoretical solution. With an appropriate assignment of relay, the results show that the cooperative system could provide a secure communication if the number of available relays is larger than that of eavesdroppers. A proper choosing the relays to transmit the information could be the important issue in the cooperative communication system.
Cooperative system is a tendency for future communications because of its spatial diversity to improve the system performance. However, the security is a critical issue in the wireless application with a highly private request. Although the encryption schemes have been proposed to approach the secure purpose, those schemes need a lot of computing resource. It is not practical for the applications with limited computing ability, such as IoT. According to Shannon theory of perfect secrecy, the security could be implemented on the physical layer. Based on the positive secrecy rate, the evaluation of security, secure communication could be practical. This work concentrates on the theoretical solution to the secrecy rate in the AF mode cooperative communication system. Also, the numerical results with the proposed methodology are given. It shows the effects of eavesdropper could not affect the secure communication if the number of the eavesdropper is less than that of relays in the system. The appropriate relay assignment benefits the secure communication.
Due to the character of low cost and easily to implemented, the cooperative communication is the future tendency. Three fundamental mode, Amplify-and-Forward (AF) mode, Decode-and-Forward (DF) mode and Compress and Forward (CF) mode are employed to the system. In the cooperative system, relays function to transmit the delivered signal to the destination. Each node in the system could play as the source station, the relay and the destination station. Currently, the issue of privacy and security are seriously requested in the communication. There could be the eavesdroppers pre-tend as the relay to steal the message. Hence, the secrecy protection becomes important. In the higher layer, the encryption scheme is applied to protect the message. However, it is difficult for those devices with low computing resources, the example of IoT (Internet of Things). With Shannon Theory, a secure communication could be supported with a positive secrecy rate. Hence, secure cooperative communication could be possible if there exist a positive secrecy rate between the two ends in the transmissions. Base on the secrecy rate analysis, the maximum secrecy rate is the initial step toward a secure communication. In the cooperative system, the delivered signal could be transmitted via relays. Hence, the path from the source to the destination could be a huge combination. With the exhaustive method to find the optimal secrecy rate could be realized. Hence, in this work, the numerical experiment, the AF and DF mode cooperative mode is adopted.
Privacy and security have an increasingly important role in wireless networks. A secure communication enables a legitimate destination to successfully retrieve information sent by a source, while it disables the eavesdropper (illegitimate destination) to interpret the intercepted information. Physical (PHY) layer security approaches for wireless communications can prevent eavesdropping without encryption. It exploits the physical characteristics of the wireless channel in order to transmit messages securely. They are typically feasible when the source-destination channel is better than the source-eavesdropper channel. Cooperative schemes are a means to improve the performance of secure wireless communications. We propose an improved relay selection scheme, based on source-eavesdropper channel SNR restriction, that will guarantee the best secrecy rate at the destination under QoS condition. Performance has been studied in terms of secrecy rate, outage probability and average error probability. Simulations shows that the proposed scheme outperforms in terms of the secrecy rate at the destination when compared to techniques in the literature.
The prominence of the wireless communication has been urging the monotonically increasing demand of security and privacy. In wireless systems, the notion of perfect secrecy of information with respect to illegitimate nodes can be ensured via physical layer security (PLS) techniques. Unfortunately, they can be made less effective if source- eavesdropper wiretap channel is better than the main source-receiver channel. The various node cooperation schemes can be employed to combat this limitation where a relay node assists the communication to improve the performance significantly. In this paper, a four node wireless communication system consisting of a source, a destination, a relay and an eavesdropper as wire-tapper has been considered. The performance of the traditional cooperation schemes in terms of secrecy rate has been investigated with a different scenario where relay node helps the eavesdropper to deteriorate the secrecy rate. In addition, since legitimate receiver can overhear the transmission of relay, it favours the achievable secrecy rate. We formulate an analytical expression of conditional secrecy outage probability for the investigated system. From the obtained simulation results, it has been observed that secrecy rate is monotonically increases with path loss index. Furthermore, the proper selection of the system parameters leads to enhance the secrecy performance of the system even if relay pertains to degrade the performance. Amplify-and-forward, cooperation, decode-and-Forward, secrecy rate, relay.
As Internet of Things (IoT) has boomed in recent years, many security issues have also been exposed. Focusing on physical layer security in wireless Internet of Things network communication, a series of security methods have been widely studied. Nevertheless, cooperative jamming methods in physical layer security to fight against collusive eavesdroppers have not been thoroughly studied yet. In this article, we study a cooperative-jamming-based physical layer secure transmission scheme for Internet of Things wireless networks in the presence of collusive eavesdroppers. We design a cooperative jamming strategy without knowing the channel state information of eavesdroppers. Considering the cooperation of multiple nodes with multiple antennas, this strategy can maximize the signal-to-interference-plus-noise ratio at an actuator (legitimate receiver). Meanwhile, the generated cooperative jamming signals can reduce the signal-to-interference-plus-noise ratio at eavesdroppers. To explore the theoretical security performance of our strategy, we perform a secrecy outage probability analysis and an asymptotic analysis. In the cases of cooperative jamming and without cooperative jamming, the closed-form expressions of the secrecy outage probability are deduced, and the influence of system parameters on the secrecy outage probability becomes more intuitive through a strict mathematical asymptotic behavior analysis. In addition, considering the energy limitation of Internet of Things devices, we propose a power allocation algorithm to minimize the total transmission power given the security requirements. The numerical results show the effectiveness of our schemes and are consistent with the theoretical analysis.
Security is an important aspect for the future wireless networks. Since the number of network nodes increases constantly, and, in addition, the networks are decentralized and ad-hoc in nature, it becomes more challenging to apply the current cryptographic methods that require exchange of keys between the communicating parties. Information-theoretic secrecy is an emerging security field that explores the possibility of achieving perfect secrecy data transmission between the intended network nodes, while possible malicious nodes (also called eavesdroppers) are kept ignorant of the transmitted information. In other words, that is the ability of the physical layer to provide security (beside the reliability) of the transmitted (broadcasted) data. For that reason, it is often called physical layer security. In this paper we observe how a simple cooperative network with one relay node can improve the physical layer security by decreasing the area in which the eavesdropper can reside and listen to the information transmitted to the destination. This region is called vulnerability region and we provide its characterization. Under certain conditions, the vulnerability region vanishes, which makes our wireless system perfectly secure for any position of the eavesdropper within the wireless network.