Physical layer security: secrecy performance analysis and design of cooperative communication systems

Security aspects of wireless networks have gained increasing interest in the field of communication security. Due to the nature of wireless networks potential security risks, vulnerabilities and threats are still a possibility, such as eavesdropping and denial of service attacks, which have been an interesting subject for many researchers. To minimise the security risks of such attacks, researchers have attempted to secure the upper layers of the OSI model by proposing various methods of encryption, such as symmetric and asymmetric encryption techniques. However, such techniques are very demanding in terms of power consumption and network resources.
Therefore, a new research direction has shifted the focus from the upper layers to exploit physical layer characteristics to enhance communication security with energy-efficient solutions, such as fading and noise. The notion of information-theoretic security was initially introduced by Shannon. It stipulates that secure communication is still possible even in the presence of eavesdroppers with infinite computing powers.
Additionally, there has been growing interests in investigating the physical layer’s security issues in various cooperative relay communication schemes. In cooperative communication, relay nodes are permitted to cooperatively help in transmitting data from the source to the legitimate destination, taking advantage of the wireless nature of the network. Several relay strategies were introduced – such as decode-and-forward (DF) and amplify-and-forward (AF). The use of such strategies has proven, theoretically, to improve the performance of secure communication and to increase network energy saving.
The major contributions of this work was to devise and implement a secrecy performance analysis for a Single-Input Single-Output (SISO) system with Nakagami-m fading. Unlike many studies that have investigated the dissimilar fading scenarios, there was a need to close the gap in the literature by proposing, presenting and analysing similar fading scenario for SISO system that underwent a similar fading, Nakagami-m. The validation process of the derived closed form was simulated and evaluated to validate the analytical analysis carried out in this research work.