Open AccessAchievable secrecy rate of wiretap channels incorporating multi‐input–multi‐output amplify and forward relaying
Author(s) -
Mirzaee Meysam,
Akhlaghi Soroush
Publication year - 2016
Publication title -
iet communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.355
H-Index - 62
eISSN - 1751-8636
pISSN - 1751-8628
DOI - 10.1049/iet-com.2015.0208
Subject(s) - beamforming , relay , secrecy , computer science , transmission (telecommunications) , gaussian , rank (graph theory) , closed form expression , secure transmission , topology (electrical circuits) , mathematical optimization , telecommunications , mathematics , combinatorics , computer security , power (physics) , mathematical analysis , physics , quantum mechanics
This study discusses the secrecy rate of two‐hop relay‐assisted cooperative wiretap channels, incorporating multi‐antenna amplify and forward relaying in the middle of transmission. In this regard, under the Gaussian code book assumption, three main scenarios including null‐space beamforming (NSBF), rank‐1 beamforming (RBF), and the so‐called general rank beamforming (GRBF) are proposed to be employed at the relay where their achievable secrecy rates are studied. Accordingly, for NSBF, a closed‐form solution is derived, whereas the corresponding optimisation problems are formulated for the remaining cases as a standard semi‐definite programming problem. Though GRBF ranks the first in terms of the achievable secrecy rate, RBF exhibits favourable results with a much lower complexity, as the corresponding optimisation problem runs over a reduced dimension. Moreover, NSBF has a much lower complexity, as it provides an analytical solution at the expense of a decrease in the secrecy rate, and interestingly, it performs quite well when the number of eavesdroppers is less than that of the relay antennas.