  In this paper, we investigate the multiple-input multiple-output (MIMO)
transceiver design under an interesting power model named mixed power
constraints. In the considered power model, several antenna subsets are
constrained by sum power constraints while the other antennas are subject to
per-antenna power constraints. This kind of transceiver designs includes both
the transceiver designs under sum power constraint and per-antenna power
constraint as its special cases. This kind of designs is of critical importance
for distributed antenna systems (DASs) with heterogeneous remote radio heads
(RRHs) such as cloud radio access networks (C-RANs). In our work, we try to
solve the optimization problem in an analytical way instead of using some
famous software packages e.g., CVX or SeDuMi. In our work, to strike tradeoffs
between performance and complexity, both iterative and non-iterative solutions
are proposed. Interestingly the non-iterative solution can be interpreted as a
matrix version water-filling solution extended from the well-known and
extensively studied vector version. Finally, simulation results demonstrate the
accuracy of our theoretical results.
