Power-Efficient Spatial Multiplexing for Multiantenna MANETs

The authors consider the problem of minimizing network's transmit power for given transmission rate demands of all links in a Multi-Input Multi-Output (MIMO) ad hoc network. The problem is non-convex, hence, challenging to be solved, even in a centralized manner. To derive a distributed solution, they reformulate the problem as a non-cooperative game. They then propose a Network Interference Function (NIF) that captures the total interference incurred at unintended receivers by all transmitters. The proposed NIF sets the light for designing transmitter-dependent pricing policies for the above game. A Price-based Iterative Water-Filling algorithm (PIWF) is proposed to find MIMO precoding matrices, which determines both beam directions and transmission power allocation among antennas (or data streams) at each transmitter.