Multiple In, Multiple Out (Mimo) - Black Box SmartPath LWN602A User Manual

3.4.1 Multiple In, Multiple Out (MIMO)

Multiple In, Multiple Out (MIMO) is a major WLAN advancement introduced in the IEEE 802.11n standard in which multiple RF
links are formed on the same channel between the transmitter and receiver simultaneously. To accomplish this, the transmitter
separates a single data stream into multiple spatial streams, one for each RF chain (an antenna + various digital signal processing
modules linked to the antenna). The transmit antennas at the end of each RF chain then transmit their spatial streams. The recipi-
ent's receive antennas obtain streams from all the transmit antennas. In fact, because of multipath, they receive multiple streams
from each transmit antenna. The receive antennas pass the spatial streams to the digital signal processors in their RF chains, which
take the best data from all the spatial streams and reassemble them into a single data stream once again (see Figure 3-10).
802.11n wireless client
with two antennas
Digital Signal
Processors
Data
Data
Chapter 3: The SmartPath AP (LWN602HA) Overview
Generally, orient the antennas vertically
for improved radio coverage, as shown here:
When mounting the SmartPath
AP (LWN602HA) on a ceiling,
orient its antennas downward.
When mounting the SmartPath AP
on a wall or post, fully extend its
antennas upward and downward.
When mounting the SmartPath AP
above a ceiling or on a horizontal
beam, orient its antennas upward.
Figure 3-9. SmartPath AP antennas, installed.
RF Chains RF Signals (Multipath)
Transmit
Antennas
Figure 3-10. 2x2 MIMO (2 transmit antennas x 2 receive antennas).
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Object
Receive
Antennas
SmartPath AP using
two antennas
RF Chains
Digital Signal
Processors
Reassembled
Data
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