Clients That Support Three Spatial Streams - Cisco Aironet 1600 Deployment Manual

802.11n, Spatial Streams, and Beamforming
The AP 2600, while similar to the AP 3600, is slightly different since it is a 3x4:3. This means that the
AP 2600 also has four antennas to help on the receive (upstream signal) but uses only three transmitters
on the downstream side.
The yellow sections of the MCS chart (see Figure 54) depict the faster data rates supported by the AP
3600. The AP 3600 supports 802.11a/b/g rates as well as 802.11n rates of MCS values 0-23.
Figure 54 AP 2600/3600 Supports up to 450 Mbps (MCS Rates 0-23); AP 1600 (MCS Rates 0-15)
These additional MCS rates permit more choices for the client supporting 3SS when making rate-shifting
decisions, since the rate-shifting algorithm maintains the best overall throughput connection.

Clients That Support Three Spatial Streams

Clients with 3SS support are now more common. As the new 802.11ac specification becomes more
accepted, many newer client adapters will have the newer chipsets and support 3SS as a subset to
802.11ac. Unlike many competitors, the AP 1600/2600 and the AP 3600 fully support all the DFS
channels for more usable channels in the 5 GHz range. More clients, especially 802.11ac clients, will
start to emerge and support these newer channels in 802.11n modes.
Currently the most popular 3SS client is the Apple 2011 MacBook Pro. It is based upon the Broadcom
BCM4331 chipset and a small USB adapter (TEW 684UB) by Trendnet, based on the Ralink chipset.
The Intel 5300 and 6300 has supported 3SS for a long time. Perhaps because this card is installed in
different hardware platforms, testers have observed good throughput (+320 Mbps) on many notebooks
and reduced throughput (such as 240 Mbps) on other notebooks. If you experience low throughput with
the Intel card, try a MacBook Pro or Trendnet adapter. If they perform well, try another notebook with
the Intel card or open a case with Intel or the laptop manufacturer for a possible remedy. During the AP
3600 beta trials, Cisco observed differences in performance with different notebooks using the Intel 6300
card.
Cisco Aironet 1600/2600/3600 Series Access Point Deployment Guide
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