MU-MIMO: A Practical Example

Servicing a large number of clients that are using small packets with legacy Wi-Fi is inefficient because the overheads incurred by the preamble and other mechanisms tend to dominate. OFDMA is ideally suited for this scenario because it divides up the channel and services up to 37 users (for 80MHz bandwidth) simultaneously, which amortizes the overhead. OFDMA improves system efficiency, but it does not necessarily improve throughput.

MU-MIMO (Multi-User, Multiple input, Multiple output) creates spatially distinct separate channels between the transmitter and each of a small number of receivers such that each receiver hears only the information intended for itself, and not the information intended for other receivers. This means that the transmitter can, by superposition, transmit to a few receivers simultaneously,increasing the aggregate throughput by a factor equivalent to the number of receivers being serviced.