Eliminating Out-Of-Cell Interference In Cellular Massive Mimo With A Single Additional Transceiver

Wireless cellular communication networks are bandwidth and interference limited. An important means to overcome these resource limitations is the use of multiple antennas. Base stations equipped with a very large (massive) number of antennas have been the focus of recent research. A bottleneck in such systems is the cost of a large number of transmit/receive chains requiring ADCs, low noise amplifiers and power amplifiers. The present work considers a line-of-sight channel model. It is shown that given a sufficiently large antenna array, it suffices that the number of transmit/receive chains exceeds the number of desired users by one in order to reduce the interference to any desired level. Furthermore, by judiciously selecting the antennas, the resulting channel is nearly orthogonal.