Fast estimation of weight vectors to optimize multi-transmitter broadcast channel capacity

We improve capacity of broadcast channels by employing multiple transmitters and exploiting the spatial diversity among the users. We derive fast algorithms to compute orthogonal, near-optimal, and optimal weight vectors for broadcasting message signals to two and three users. The key innovation is that we decouple the weight vectors in the measure of channel capacity to (1) simplify the optimization problem to a search for the maxima of a smooth multidimensional function and (2) derive closed-form expressions for the orthogonal and near-optimal algorithms.