Improving MIMO Secrecy Rate through Efficient Power Allocation.

We study the problem of maximizing the secrecy capacity in multiple input multiple output (MIMO) communication systems in the presence of an eavesdropper using optimal power allocation. One of the key bottlenecks arise in identifying the appropriate spatial streams to securely transmit data and the corresponding transmit powers to maximize capacity. We employ the generalized singular value decomposition (GSVD) technique to identify these spatial streams and propose a power allocation scheme over these spatial streams. We also present an upper bound for the maximum achievable secrecy rate under certain conditions. We show that the proposed power allocation technique not only achieves better secrecy, but also converges to the upper bound faster than those in the literature.