Multi-user MIMO

In contrast, single-user MIMO (SU-MIMO) involves a single multi-antenna-equipped user or terminal communicating with precisely one other similarly equipped node.

MU-MIMO leverages multiple users as spatially distributed transmission resources, at the cost of somewhat more expensive signal processing.

To remove ambiguity of the words receiver and transmitter, we can adopt the terms access point (AP) or base station, and user.

Examples of advanced-transmit processing for MIMO BC are interference-aware precoding and SDMA-based downlink user scheduling.

Examples of advanced receive processing for MIMO MAC are joint interference cancellation and SDMA-based uplink user scheduling.

However, knowing CSIR costs a lot of uplink resources to transmit dedicated pilots from each user to the AP.

CO-MIMO improves the performance of a wireless network by introducing multiple-antenna advantages, such as diversity, multiplexing and beamforming.

A simple form that does not require any advanced signal processing is single frequency networks (SFN), used especially in wireless broadcasting.

To optimize the capacity of ad hoc channels, MIMO concepts and techniques can be applied to multiple links between the transmit and receive node clusters.