SWRU423A July 2015 – May 2016 WL1801MOD , WL1805MOD , WL1807MOD , WL1831MOD , WL1835MOD , WL1837MOD
The use of multiple antennas and the antenna-based multiple input, multiple output (MIMO) technique is a key feature of 802.11n equipment that sets itself apart from the earlier 802.11a/g equipment. This usage is responsible for superior performance, reliability, and range.
MIMO systems (WiLink8.0 supports 2x2 MIMO) divide a data stream into multiple unique streams, each of which is simultaneously modulated and transmitted through a different radio-antenna chain in the same frequency channel. MIMO leverages environmental structures and takes advantage of multipath signal reflections to improve radio transmission performance.
Through the use of multipath, each MIMO receive antenna-radio chain is a linear combination of the multiple transmitted data streams. The data streams are separated at the receiver using MIMO algorithms that rely on the estimates of the channels between each transmitter and receiver. Each multipath route can then be treated as a separate channel creating multiple "virtual wires" over which to transmit signals. MIMO employs multiple, spatially-separated antennas to take advantage of these "virtual wires" and transfers more data. In addition to multiplying throughput, range is increased because of an antenna diversity advantage as each receive antenna has a measurement of each transmitted data stream. With MIMO, the maximum per channel data rate grows linearly with the number of different data streams transmitted in the same channel.