Joint Relay and Jammer Selection for Secure Two-Way Relay Networks (1111.7108v1)

Abstract: In this paper, we investigate joint relay and jammer selection in two-way cooperative networks, consisting of two sources, a number of intermediate nodes, and one eavesdropper, with the constraints of physical layer security. Specifically, the proposed algorithms select two or three intermediate nodes to enhance security against the malicious eavesdropper. The first selected node operates in the conventional relay mode and assists the sources to deliver their data to the corresponding destinations using an amplify-and-forward protocol. The second and third nodes are used in different communication phases as jammers in order to create intentional interference upon the eavesdropper node. Firstly, we find that in a topology where the intermediate nodes are randomly and sparsely distributed, the proposed schemes with cooperative jamming outperform the conventional non-jamming schemes within a certain transmitted power regime. We also find that, in the scenario in which the intermediate nodes gather as a close cluster, the jamming schemes may be less effective than their non-jamming counterparts. Therefore, we introduce a hybrid scheme to switch between jamming and non-jamming modes. Simulation results validate our theoretical analysis and show that the hybrid switching scheme further improves the secrecy rate.

• The paper proposes joint relay and jammer selection strategies to enhance physical layer security against eavesdroppers in two-way relay networks using amplify-and-forward protocol.
• Theoretical and simulation results show cooperative jamming significantly improves secrecy rates (around 1 BPCU gain) at specific power levels compared to non-jamming, leading to hybrid switching scheme development.
• The research suggests practical implications for designing security protocols in wireless networks, balancing secrecy rate enhancement and eavesdropping mitigation through intelligent node selection.

Joint Relay and Jammer Selection for Secure Two-Way Relay Networks: An Analysis

The paper in focus addresses the significant challenge of securing communications in two-way relay networks by investigating joint relay and jammer selection strategies. Authored by Jingchao Chen and colleagues, the paper presents a novel approach to enhance security features in wireless networks by exploiting the physical layer. Rather than relying solely on cryptographic methods, this research examines how selecting relays and jammers can bolster security against eavesdroppers.

The paper's core contribution lies in proposing algorithms capable of selecting optimal intermediate nodes that function both as relays and as deliberate jammers. The relay employs an amplify-and-forward (AF) protocol to facilitate communication between two source nodes, while additional nodes simultaneously generate interference to confound potential eavesdroppers. This dual functionality ensures not only the enhancement of data transfer but also the degradation of unwanted interception.

Theoretical Insights

A principal finding is the identification of specific scenarios where cooperative jamming significantly outperforms conventional non-jamming methods. The authors demonstrate that, in a setting with randomly and sparsely distributed intermediate nodes, jamming provides a considerable improvement in secrecy. Conversely, when nodes are clustered together, traditional non-jamming schemes may hold an edge, leading to the development of a hybrid switching strategy that dynamically toggles between jamming and non-jamming modes based on environmental conditions.

Simulation and Numerical Results

Quantitative simulation results corroborate the theoretical predictions, highlighting that optimal performance is contingent on transmission power levels. Within a specified power range, jamming schemes markedly enhance secrecy rates, surpassing non-jamming alternatives by roughly 1 BPCU. However, at higher power levels, the secrecy rate gains from jamming diminish and eventually plateau, whereas non-jamming methods continue to exhibit linear scalability.

The authors emphasize that intelligent switching mechanisms, such as the Optimal Switching (OSW) and Suboptimal Switching (SSW) schemes, overcome inherent limitations posed by continuous jamming. The OSW scheme, while providing superior secrecy rates across the power spectrum, necessitates detailed channel state information, rendering it more complex in implementation. On the other hand, the SSW scheme relies on averaged channel data, offering practical ease without significant performance trade-offs.

Implications and Future Directions

The research sets a precedent for employing physical-layer techniques to achieve secure communications in wireless networks. The approach offers an intricate balance between enhancing the secrecy rate and mitigating eavesdropping possibilities through cooperative jamming. Practically, these findings could influence the design of security protocols in environments where eavesdropping threats are prevalent, such as in military or sensitive commercial communications.

Future work could explore the algorithm's applicability in dynamic environments where node distribution changes over time. Additionally, refining the hybrid switching mechanism based on real-time feedback will likely increase adaptability in ever-evolving network conditions. Furthermore, extending this work to other relay network topologies could unveil additional insights, potentially broadening the scope of relay-jammer selection strategies.

In conclusion, Jingchao Chen and colleagues have provided a significant contribution to physical layer security in wireless networks, offering critical insights into how relay and jammer selection can be utilized to enhance secure communications in two-way relay systems. This research opens several avenues for further exploration and underscores the potential of cooperative network strategies to mitigate eavesdropping threats.