802.11Ac Wave-2 Primer And The Ap 1850; Clients Supporting 3 And 4 Spatial Streams - Cisco Aironet 1850 Series Deployment Manual

Revised: January 25, 2017,

802.11ac Wave-2 primer and the AP 1850

For an overview of 802.11ac, see the technical white paper at the following URL:
http://www.cisco.com/c/en/us/products/collateral/wireless/aironet-3600-series/white_paper_c11-713103.html
Key differences with 802.11ac Wave-2 using the AP 1850 are:
• The ability to use 1, 2, 3 (and now 4) Spatial Streams
• An extra Spatial Stream gives you a bump in data rate @ 80 MHz 1733 versus1300 Mbps
• Same channel bonding 20, 40, 80 (does not support 160 MHz)
• 11ac Beamforming (was in Wave-1) now implemented, but only 11ac clients participate in .11ac beamforming
• Multi-User MIMO (MU-MIMO) support—supported in Wave-2 for 11ac Wave 2 clients only
• Based on IEEE 802.11ac final standard—ratified Dec'2013

Clients Supporting 3 and 4 Spatial Streams

Clients with 3SS support are starting to become a commonplace with 4SS and MU-MIMO Wave-2 clients on the horizon. As the
new 802.11ac specification starts to get traction, many newer client adapters will have more advanced chipsets and support 3SS and
4SS as a subset to 802.11ac. Additionally, the Cisco AP 1850 fully supports all the DFS frequencies for more usable channels in the
5 GHz range. More clients, especially 802.11ac clients, will start supporting these newer channels in legacy 802.11n modes as well.
Currently, the most popular 3SS client is the Apple 2011 MacBook Pro, because it is based upon the Broadcom BCM4331 chipset
and a small USB adapter by Trendnet, that is, TEW 684UB, based on the Ralink chipset.
Additionally, the Intel 5300 and 6300 modules have supported 3SS for a long time. Because of the different types of notebooks that
these cards are installed in, testers have observed good throughput on many notebooks (+320 Mbps) and reduced throughput on other
notebooks such as 240 Mbps. If you experience low throughput using the Intel card, you may 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.
Sometimes, it can be difficult to reliably maintain a 3SS link because it is easy for the client to rate-shift
Note
out of the 3SS mode. The client plays an important role in the ability to maintain a 3SS link, so it can vary
with the quality of the client being used and the test environment.