Cooperative Jamming for Secure Transmission with Finite Alphabet Input under Individual Power Constraint

Kuo CAO  Yueming CAI  Yongpeng WU  Weiwei YANG  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E101-A   No.6   pp.961-966
Publication Date: 2018/06/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E101.A.961
Type of Manuscript: LETTER
Category: Digital Signal Processing
physical layer security,  relay wights,  power control,  finite alphabet input,  

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This letter studies secure transmission design with finite alphabet input for cooperative jamming network under individual power constraint. By adopting the zero-force scheme, where the jamming signal is fully laid in the null space of the relay-destination channel, the problem of enhancing the achievable secrecy rate is decomposed into two independent subproblems: relay weights design and power control. We reveal that the problem of relay weights design is identical to the problem of minimizing the maximal equivalent source-eavesdropper channel gain, which can be transformed into a semi-definite programming (SDP) problem and thus is tackled using interior point method. Besides, the problem of power control is solved with the fundamental relation between mutual information and minimum mean square error (MMSE). Numerical results show that the proposed scheme achieves significant performance gains compared to the conventional Gaussian design.