  MIMO interference network optimization is important for increasingly crowded
wireless communication networks. We provide a new algorithm, named Dual Link
algorithm, for the classic problem of weighted sum-rate maximization for MIMO
multiaccess channels (MAC), broadcast channels (BC), and general MIMO
interference channels with Gaussian input and a total power constraint. For
MIMO MAC/BC, the algorithm finds optimal signals to achieve the capacity region
boundary. For interference channels with Gaussian input assumption, two of the
previous state-of-the-art algorithms are the WMMSE algorithm and the polite
water-filling (PWF) algorithm. The WMMSE algorithm is provably convergent,
while the PWF algorithm takes the advantage of the optimal transmit signal
structure and converges the fastest in most situations but is not guaranteed to
converge in all situations. It is highly desirable to design an algorithm that
has the advantages of both algorithms. The dual link algorithm is such an
algorithm. Its fast and guaranteed convergence is important to distributed
implementation and time varying channels. In addition, the technique and a
scaling invariance property used in the convergence proof may find applications
in other non-convex problems in communication networks.
