  We take two new approaches to design efficient algorithms for transmitter
optimization under rate constraints, to guarantee the Quality of Service in
general MIMO interference networks, which is a combination of multiple
interfering broadcast channels (BC) and multiaccess channels (MAC) and is named
B-MAC Networks. Two related optimization problems, maximizing the minimum of
weighted rates under a sum-power constraint and minimizing the sum-power under
rate constraints, are considered. The first approach takes advantage of
existing efficient algorithms for SINR problems by building a bridge between
rate and SINR through the design of optimal mappings between them. The approach
can be applied to other optimization problems as well. The second approach
employs polite water-filling, which is the optimal network version of
water-filling that we recently found. It replaces most generic optimization
algorithms currently used for networks and reduces the complexity while
demonstrating superior performance even in non-convex cases. Both centralized
and distributed algorithms are designed and the performance is analyzed in
addition to numeric examples.
