  This letter deals with the joint information and energy processing at a
receiver of a point-to-point communication channel. In particular, the
trade-off between the achievable information rate and harvested energy for a
multiple-antenna power splitting (PS) receiver is investigated. Here, the rate-
energy region characterization is of particular interest, which is
intrinsically a non-convex problem. In this letter, an efficient algorithm is
proposed for obtaining an approximate solution to the problem in polynomial
time. This algorithm is mainly based on the Taylor approximation in conjunction
with semidefinite relaxation (SDR) which is solved by interior-point methods.
Moreover, we utilize the Gaussian randomization procedure to obtain a feasible
solution for the original problem. It is shown that by proper receiver design
the rate-energy region can be significantly enlarged compared to the state of
the art, while at the same time the receiver hardware costs is reduced by
utilizing less number of energy harvesting circuitry.
