  This paper considers the joint precoder design problem for multiple-input
single-output (MISO) systems with coordinated base stations (BSs). We consider
maximization of the total sum rate with per BS antenna power constraint
problem. For this problem, we propose a novel linear iterative algorithm. The
problem is solved as follows. First, by introducing additional optimization
variables and applying matrix fractional minimization, we reformulate the
original problem as a new problem. Second, for the given precoder vectors of
all users, we optimize the introduced variables of the latter problem using
Geometric Programming (GP) method. Third, keeping the introduced variables
constant, the precoder vectors of all users are optimized by using phase
rotation technique. The second and third steps are repeated until convergence.
We have shown that the proposed algorithm is guaranteed to converge. Moreover,
for the total sum power constraint case, simulation results show that the
proposed iterative algorithm achieves almost the same average performance as
that of the algorithm which utilizes mean-square-error (MSE) uplink-downlink
duality approach. We also show that our iterative algorithm can be used to
solve sum rate maximization and weighted sum MSE minimization problems for an
arbitrary power constraint.
