Joint SVD-GSVD Precoding Technique and Secrecy Capacity Lower Bound for the MIMO Relay Wire-Tap Channel
The authors consider a problem of secure communications for the communication system consisting of multiple inputs for a source and a relay and multiple outputs for the relay, a destination and an eavesdropper. For the above-mentioned communication system, they establish a lower bound on the secrecy capacity at which secure communications between the source and the destination are attainable. They make use of the Singular Value Decomposition (SVD) and its generalization to decompose the whole system into parallel independent channels. At the source, the Generalized Singular Value Decomposition (GSVD) is performed to simultaneously diagonalize the channel matrices of the relay and the destination and independently code across the resulting parallel channels.