Chapter 4 Cooperative Jamming: The Tale of Friendly Interference for Secrecy ∗

Ersen Ekrem, Şennur Ulukuş

Vaibhav Kumar Gupta, Poonam Jindal

Cooperative jamming, a potential supplement can be used to improve physical layer based security by transmitting a weighted jamming signal to create interference at the eavesdropper. The secrecy rate is derived for cooperative jamming technique in terms of network throughput. We have analyzed the effect of Aloha protocol with cooperative jamming on the secrecy capacity of large scale network. To implement cooperative jamming with Aloha protocol a transmitter can be considered as a source or as a friendly jammer with the massage transmission probability p. We observed that an optimum level of security can be achieved for a specific value of jammer power using cooperative jamming and at the moderate value of massage transmission probability p using cooperative jamming with Aloha protocol.

Xiangyun Zhou, Lingyang Song, Yan Zhang

Physical layer security is an emerging security research area that explores the possibilities of achieving perfect secrecy data transmission between sources and intended destinations, while possible malicious eavesdroppers who intend to eavesdrop the communication links obtain zero information. However, such a security is determined by the wireless channel conditions: if the channel between source and destination is worse than the channel between source and eavesdropper, the secrecy rate is typically zero. To overcome this limitation, cooperative jamming is considered as a promising approach where selected jammers can transmit jamming signals to interfere with the malicious eavesdroppers and thus the secrecy capacity can be effectively improved. In this chapter, we consider the jamming power allocation issue in a jammer-assisted cooperative wireless network. The secrecy rate of the source-destination links can be optimized utilizing a well-chosen amount of jamming power from the friendly jammer, and thus each source that can benefit intends to obtain an optimal jamming power to maximize its secrecy rate for data transmission. Then, the problem comes to how to effectively allocate the limited jamming power owned by the friendly jammer among the sources in demand to achieve an optimized system performance. By considering the friendly jammer as the auctioneer and the sources as the bidders, we formulate this power allocation problem as an auction game model, and introduce three distributed auction-based power allocation schemes, i.e., Power allocation scheme based on Single object pay-as-bid Ascending Clock Auction (P-ACA-S), Power allocation scheme based on Traditional Ascending Clock Auction (P-ACA-T), and Power Allocation Scheme based on Alternative Ascending Clock Auction (P-ACA-A). In addition, we investigate some basic properties of the proposed three auction-based power allocation schemes, i.e., convergence, cheat-proof property, and social welfare maximization.

Şennur Ulukuş, Ersen Ekrem

Zhifan Xu, Melike Baykal‐Gürsoy

Haiyang Zhang, Lingjie Duan

Cooperative jamming approach has been commonly used in the field of physical layer security to achieve a good secrecy rate of wireless networks. In this approach, the Gaussian noise signal sent by a friendly jammer can disrupt the reception of the eavesdropper, however, it may also interfere with the legitimate receiver. In this paper, we propose a novel approach, namely, information jamming, to go beyond the secrecy rate achieved by the traditional cooperative jamming approach in a multiple-input single-output (MISO) wiretap channel. We propose that a multi-antenna friendly jammer transmits the source message rather than Gaussian noise signal for simultaneously enhancing the signal strength at the legitimate receiver and canceling the received signal at the eavesdropper. In particular, we aim to maximize the achievable secrecy rate by optimizing the information jammer's beamforming vector. Though the optimization problem is non-convex, we successfully solve it optimally via a two-stage based numerical approach. To gain more useful analytical results, we also propose two suboptimal jamming schemes with low computation, by targeting at improving the legitimate reception and avoiding the eavesdropping, respectively. Finally, numerical results show that the proposed information jamming approach significantly helps go beyond the secrecy rate of the existing cooperative jamming approach, especially when the transmit power of the jammer is large enough.