Cisco Aironet 1700 Deployment Manual page 44

Figure 59 Beamforming (constructive and destructive interference)
Figure 60 provides a visual comparison of ClientLink 1.0, using 1 spatial stream, and ClientLink 2.0, using 3 spatial streams.
Unlike the AP 3500, the AP 3600 provides multiple spatial streams using four transceivers for even greater performance. AP
3600 can beamform to all 802.11a/g and 802.11n 1, 2 and 3 spatial stream clients. The signal is x3 as each stream is
beamformed.
Figure 60 Example of ClientLink (directing the signal to a client, in this case 1 spatial stream)
In order to beamform to clients using 3 spatial streams, since 3 transmitters are used in the transmissions,
Note
the AP needs at least one additional radio to beamform. The AP 3600 and AP 3700 use 4 radios per band
and can beamform to clients using 3 spatial streams.
Cisco Aironet Series 3700 Access Point
Cisco Aironet Series 1700/2700/3700 Access Point Deployment Guide
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