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802.11ac: The Next WLAN Wave Gigabit Wireless in 2013

Position Overview The next wave of WiFi standards promises to bring wired speed to the airwaves while opening up the “cleaner” 5GHz spectrum for greater utilization. Juniper Networks is actively supporting the development of the IEEE 802.11ac standard and plans to incorporate IEEE 802.11ac innovations into its line of enterprise-class access points in the near future. This will ensure that Juniper continues to deliver the best-performing, Wi-Fi-certified access points with the most complete feature set while minimizing deployment churn for customers. The currently shipping Juniper WLAN controllers are capable of supporting 802.11ac access points, so customers can deploy a Juniper 802.11n network today with confidence that they are building an 802.11ac-ready wireless network.

Although true 802.11ac enterprise-class devices will not be available until later in 2013, some vendors will rush to bring 802.11ac access points to market in advance of full standards ratification in order to claim “first to market” status. However, these vendors run the risk of last-minute changes to the standard. For instance, the early 802.11ac chipsets will not support multi-user MIMO (MU-MIMO). Those purchasing early versions of 802.11ac access points will likely want to upgrade radios to gain the advantages of MU-MIMO once the next revision chip sets are available. Juniper plans to deliver 802.11ac APs based on the initial single-user MIMO (SU-MIMO) chipsets to meet the early adopter requirements for gigabit wireless and, later, MU-MIMO. MU-MIMO-capable chipsets are only expected to be available in mid 2014 (for all vendors), with full MU-MIMO-capable access points following later in the year.

While some customers will want to adopt 802.11ac in advance of MU-MIMO, most are more likely to wait for fully ratified 802.11ac APs with the latest chipsets. To gain full advantage of 802.11ac, especially for very high client density environments, Juniper recommends waiting for MU-MIMO to realize the full benefits of 802.11ac. However, for customers who have not yet upgraded their WLAN to 802.11n and don’t want to delay their refresh cycle, Juniper recommends upgrading now to the highest-performance and fully featured 802.11n APs with 3x3 MIMO and 3 spatial streams, such as the WLA532.

Customers concerned about preparing their networks for IEEE 802.11ac do need to consider implications beyond the access points. The implications of supporting 1Gbps wireless traffic are not trivial, as they directly affect the capacity of the WLAN controllers in your network. Fortunately, Juniper’s WLAN controllers are all 11ac compatible.

IEEE 802.11ac Standard Background IEEE 802.11ac, the latest 802.11 wireless Physical Layer technology standard still under development, brings gigabit speeds to WLANs and, more importantly, the ability to support simultaneous wireless service to multiple stations.

There are two key flavors of Physical Layer implementations: SU-MIMO and MU-MIMO. SU-MIMO (single user multiple input and multiple output) provides connectivity to one user at any given time, whereas MU-MIMO provides simultaneous service to multiple stations. The standard also specifies the ability to support Physical Layer data rates of up to 6.93 Gbps, up to eight additional MIMO spatial streams, up to 160MHz wide RF bandwidth, and up to 256QAM high-density modulation. It must be noted that the actual application data throughput in 802.11 technologies is usually less than the physical data rate.

The following are key feature specifications expected in the new standard:

802.11ac: The Next WLAN Wave

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• Support for 5GHz UNII band • Wider channel bandwidths—80MHz (mandatory), 160MHz (optional), 80+80MHz (optional) in addition to 20MHz and

40MHz • Up to six 80MHz channels and up to two 160MHz channels in the FCC domain • MIMO spatial streams—mandatory 1-stream with support for up to eight spatial streams; Wi-Fi Alliance Certification

will require a mandatory minimum of two streams on APs • Multi-user MIMO (MU-MIMO):

- Multiple stations, each with one or more antennas, transmit- or receive-independent data streams simultaneously - Downlink MU-MIMO (one transmitting device, multiple receiving devices) included as an optional mode

• Modulation 256-QAM, rate 3/4 and 5/6, added as optional modes • New MCS 8 and MCS 9 in addition to support for MCS 0 to 7 • Transmit beam-forming—single sounding and feedback format • MAC Layer modifications to support above changes • Coexistence mechanisms for 20/40/80/160MHz channels • Fully backwards compatible with 802.11a/n stations

Industry Status The standard is expected to be completed in 2H 2013, with final ratification expected in late 2013 to early 2014. Much like 802.11n, we expect pre-standard product rollout before ratification starting in early 1H 2013, with the first wave of WFA certification based on the 802.11ac draft 3.0 occurring in the same time frame.

We expect the first-generation 802.11ac enterprise class products will implement the SU-MIMO portion of the specification with support for up to three spatial streams (up to 1.3Gbps) in 2013. Most smart phones and tablets require a single chip solution, which is not expected until the latter half of 2013. Therefore, wide 802.11ac adoption won’t occur until late 2014.

Also, the enhanced version of 802.11ac, also known as MU-MIMO, is expected to be supported by the next generation of 802.11ac enterprise products starting in late 2014.

Benefits Speed and clean spectrum are the greatest and most anticipated benefits.

• Up to 33% increase in Physical Layer data rates due to higher modulation • Gigabit speeds due to more spatial streams, wider channel bandwidths and higher modulation • Lower power consumption and enhanced battery life on clients due to faster transmission rates • Lower interference in the 5GHz spectrum, more suitable for multimedia applications sensitive to packet loss and

delay and requiring high throughput, such as voice and video • Transmit beamforming increases throughput by providing directional signal reception and transmission thereby

improving the quality of the signal sent to wireless clients

Challenges This new speed will bring with it some considerations and challenges for successful deployments.

• Higher modulation and wider channel bandwidths in 802.11ac require tight design margins and are also more susceptible to higher propagation loss and interference.

• The majority of the client device population will still be 1-stream or 2-stream 802.11n stations for the next two to three years. Therefore, most deployments will be mixed environments, limiting the maximum possible throughput capacity.

• 802.11ac product pricing will most likely be much higher than 802.11n products.

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Corporate and Sales Headquarters Juniper Networks, Inc. 1194 North Mathilda Avenue Sunnyvale, CA 94089 USA Phone: 888.JUNIPER (888.586.4737) or 408.745.2000 Fax: 408.745.2100

APAC Headquarters Juniper Networks (Hong Kong) 26/F, Cityplaza One 1111 King’s Road Taikoo Shing, Hong Kong Phone: 852.2332.3636 Fax: 852.2574.7803

EMEA Headquarters Juniper Networks Ireland Airside Business Park Swords, County Dublin, Ireland Phone: 35.31.8903.600 EMEA Sales: 00800.4586.4737 Fax: 35.31.8903.601

Copyright 2012 Juniper Networks, Inc. All rights reserved. Juniper Networks, the Juniper Networks logo, Junos, NetScreen, and ScreenOS are registered trademarks of Juniper Networks, Inc. in the United States and other countries. All other trademarks, service marks, registered marks, or registered service marks are the property of their respective owners. Juniper Networks assumes no responsibility for any inaccuracies in this document. Juniper Networks reserves the right to change, modify, transfer, or otherwise revise this publication without notice. December 2012