Mobile MIMO capacity in network interference: Informed and Uninformed Transmitters

Multiple-Input Multiple-Output (MIMO) receivers maximize link throughput by finding the best balance between enhancing signal power and suppressing interference. This makes MIMO a good candidate for Mobile Ad-hoc Networks (MANETs) with network interference. It has been shown previously that MIMO achieves higher throughput in network interference if transmitters reduce the number of transmit antennas or modes (data streams) used. That result is confirmed here using a more realistic model than that previously employed, including Rice fading, log-normal shadowing, and range-loss exponents and shadowing standard deviations that grow with range. Ordinarily, limiting the number of transmit modes requires some sort of enforcement policy. Informed Transmitter (IT-) MIMO links with Channel State Information (CSI) feedback optimize single-link performance in severe interference by reducing the number of transmit modes and concentrating available power in the strongest. It is shown here that this reduction in IT-MIMO signal complexity results in network performance close to that of network-optimized Uninformed Transmitter (UT-) MIMO, without the need for network coordination.