Adapting the number of transmitting antennas in mobile networked MIMO (MNM)

We investigate a MIMO communications system that uses linear MMSE receiver processing to separate the spatial streams. In fading environments that do not exhibit "rich scattering", it is beneficial to reduce the number of active transmitters, even when this implies a reduction in total transmit power. A practical method is suggested to determine the number of transmitters to activate in a particular local propagation environment, based on a prediction of the frame error rate. Our approach uses "slow feedback" of the requested transmission mode, meaning that the selected rate should be sustainable over future Rayleigh instantiations of the same channel.