Physical layer security: secrecy capacity analysis for multiuser networks using joint SVD-GSVD precoding technique

Abstract

In this thesis, the problem of Physical Layer (PHY) Security is considered. This problem deals with secure signal transmission for a Multiple-Input Multiple-Output (MIMO) system using a relay i.e. the signal is transmitted in such a way so that even if it is received by some illegal receiver, called as the eavesdropper, besides the intended receiver, the former will not be able to decode it. This problem occurs in all wireless communication systems which use broadcast technique since in this technique, the signal is received by every receiver, even if some of them are not intended for it. To transmit the signal securely, signal beamforming is performed at the transmitter as well as the receiver. many techniques are used to perform beamforming for e.g. Singular Value Decomposition (SVD), Generalized Singular Value Decomposition (GSVD), etc. In here, the combination of these two techniques, Joint SVD-GSVD precoding technique, is used to achieve this purpose. Secrecy rate is the parameter for measuring the performance of secure transmission. Here, the lower bound on the secrecy rate for a wireless communication system is analyzed. The results are derived, for different channel conditions, giving a brief review about the effect of Channel State Information (CSI) measurement on the reception of the data.