Joint Relay Selection and Power Allocation in Large-Scale MIMO Systems with Untrusted Relays and Passive Eavesdroppers

In this paper, a joint relay selection and power allocation (JRP) scheme is proposed to enhance the physical layer security of a cooperative network, where a multiple antennas source communicates with a single-antenna destination in presence of untrusted relays and passive eavesdroppers (Eves). The objective is to protect the data confidentially while concurrently relying on the untrusted relays as potential Eves to improve both the security and reliability of the network. To realize this objective, we consider cooperative jamming performed by the destination while JRP scheme is implemented. With the aim of maximizing the instantaneous secrecy rate, we derive a new closed-form solution for the optimal power allocation and propose a simple relay selection criterion under two scenarios of non-colluding Eves (NCE) and colluding Eves (CE). For the proposed scheme, a new closed-form expression is derived for the ergodic secrecy rate (ESR) and the secrecy outage probability as security metrics, and a new closed-form expression is presented for the average symbol error rate (SER) as a reliability measure over Rayleigh fading channels. We further explicitly characterize the high signal-to-noise ratio slope and power offset of the ESR to highlight the impacts of system parameters on the ESR. In addition, we examine the diversity order of the proposed scheme to reveal the achievable secrecy performance advantage. Finally, the secrecy and reliability diversity-multiplexing tradeoff of the optimized network are provided. Numerical results highlight that the ESR performance of the proposed JRP scheme for NCE and CE cases is increased with respect to the number of untrustworthy relays.Comment: 18 pages, 10 figures, IEEE Transactions on Information Forensics and Security (In press

Additional file 5: Table S2. of Spatial regulation of monolignol biosynthesis and laccase genes control developmental and stress-related lignin in flax

Description of the gene expression localization in the tissues of flax roots, stems and leaves. (JPEG 391 kb

Additional file 4: Figure S3. of Genetic association of stomatal traits and yield in wheat grown in low rainfall environments

Morphological features of a single stomata. Arrows indicate aperture length (APL) and width (APW) and guard cell length (GCL) and width (GCW). Aperture area (APA) and guard cell area (GCL) were calculated by multiplying the length and width of the rectangle. (DOCX 261 kb

Additional file 1: Figure S1. of Genetic association of stomatal traits and yield in wheat grown in low rainfall environments

Frequency distribution of phenotypes for stomatal size related traits and yield in the RAC875/Kukri DH lines based on means obtained over each experiment. a) Lameroo, b) Roseworthy, c) Well watered conditions in the glasshouse, d) Drought conditions in the glasshouse. Arrows indicate phenotypic values of RAC875 (R) and Kukri (K). (PPTX 264 kb