Physical Layer Security in Buffer-State-Based Max-Ratio Relay Selection Exploiting Broadcasting With Cooperative Beamforming and Jamming

Abstract

In this paper, we propose a novel secure bufferaided decode-and-forward relay selection that amalgamates the benefits of the buffer-state-based relay selection, the max-ratio criterion, the simultaneous activation of multiple source-to-relay links, and the cooperative beamforming in dual-hop networks. More specifically, the proposed scheme is designed for selecting a single or multiple relay nodes for packet reception or transmission based on the buffer states of relay nodes, while avoiding the detrimental effects of both an empty buffer state and a buffer overflow. Analytical bounds on the secrecy outage probability and the average delay are derived for our proposed scheme, based on a Markov chain process, in order to verify the system model of our proposed scheme. Furthermore, we introduce the concept of cooperative jamming into the proposed scheme, in order to interfere with an eavesdropper's reception, while dispensing with the full channel state information associated with an eavesdropper at a central coordinator. Our simulation results demonstrate that the proposed schemes outperform the existing buffer-based secure relay selection schemes, in terms of both the secrecy outage probability and the average delay, as the explicit benefits of our novel introduced concepts.

Generalized Buffer-State-Based Relay Selection in Cooperative Cognitive Radio Networks

“…These two schemes are capable of attaining a lower average packet delay than the original MMRS and max-link counterparts, owing to the beneficial effects of packet sharing among the relay nodes. Furthermore, the concept of BSB relay selection was proposed in [9], which was then introduced into the beamforming-assisted G-ML scheme [12], the fullduplex scheme [24], the NOMA-based downlink [25], and the secure relaying scheme [13]. Since one of the challenges in the buffer-aided relaying protocols is an increased packet delay [3], the relay selection scheme in [26] was proposed for achieving a significant reduction of the packet delay, compared to the max-link scheme [6] by introducing a priority on the relay selection criterion.…”

“…Additionally, we assume that there are stable low-rate feedback channels, where an acknowledge (ACK) packet is sent from the SD node to all the SR nodes if the SD node successfully decodes the packet. Note that this is the same assumption as that considered in [10][11][12][13]. Since we assume that the SD node periodically transmits control packets to the SR nodes, the ACK packet can also be sent in a piggyback manner.…”

“…However, in the conventional relay selection schemes, the achievable diversity order is limited to the number of relay nodes, due to the prefixed schedule of reception and transmission [3]. In order to enhance the achievable diversity performance of the conventional relaying schemes, the buffer-aided cooperative relaying protocols have attracted much attention [4][5][6][7][8][9][10][11][12][13][14][15][16]. In the buffer-aided relay selection, the best source-to-relay (SR) and relay-to-destination (RD) links are selected separately [4], while the conventional relay nodes are designed for forwarding the received packet immediately to the destination node [1].…”

“…In order to combat the limitations, a number of buffer-aided relay selection schemes were proposed for taking into consideration the buffer state information of each relay node [9][10][11][12], [14]. Also, the buffer-aided relaying protocols are introduced into the context of the physical layer security, which guarantees the information-theoretic secure communications [8], [13].…”

Joint Optimization of Power Splitting and Beamforming in Energy Harvesting Cooperative Networks

“…In [22], a compressive survey of recent cooperative relaying and jamming techniques was presented. In [23], Nakai et al proposed to select relay sets based on buffer states and introduced cooperative jamming into the proposed buffer-statebased relay system. In our earlier work [24], we proposed to select the single best relay and multiple jammers for improving the PLS of cooperative relay networks, and focused on the joint optimization of relay selection and power allocation for maximizing the secrecy rate.…”