802.11ac: The New Standard for Very High Throughput

Meeting the data rate demands of the growing wireless community using high-bandwidth applications



802.11ac Overview

A new IEEE standard is in the wings ready to make its debut on the wireless market stage: 802.11ac.  

802.11ac builds upon the success of 802.11n which is now the predominant WLAN standard in the market. 802.11n brought improvements in data rates and link efficiencies; however, consumer and commercial trends have created demand for a new set of capabilities which are addressed by 802.11ac (see Table 1).

Table 1 - 802.11ac Major Features Enhancements

802.11ac Features Customer Benefits
Wider channels Higher data rates – up to 1.3Gbps per radio
Higher encoding density Higher bit density per packet
Increased number of spatial streams Higher data rates per AP/client link
Beamforming Greater wireless AP/client link reliability
Multi-user MIMO Greater AP/client capacity and efficient use of spectrum


The cumulative benefit of 802.11ac features will enable Wi-Fi solutions to meet today’s demand for high capacity and high quality mobile real-time applications like video and voice.

802.11ac White Paper - Understanding the New IEEE Standard

 

Why is 802.11ac needed?

As the commercial population becomes more mobile, two trends have emerged for Wi-Fi solutions to address:

  1. Mobile applications now demand more bandwidth – Video and voice applications have increased the demand for pervasive bandwidth…everywhere.
  2. Individuals carry multiple wireless devices – With an average corporate mobile device/user ratio approaching 2.7  (laptop, tablet, and/or smartphone), client congestion has become a problem for wireless networks.

The challenge for 802.11ac is to meet today’s functional demands and the explosive wireless market growth that is expected over the next three to five years.

IDC Tech Brief - The Promise of 802.11ac

 

802.11ac explained

The 802.11ac standard addresses these new business requirements to achieve the goal of higher data rate and greater link reliability by sophisticated RF architectural enhancements that include:

  • Wider channel support – 802.11ac mandates support of 80MHz wide channels with optional 160MHz wide channels to achieve higher data rates than are achieved with 802.11n.

Table 2 - 802.11ac Data Rates by Channel Width

  Channel Width
# Spatial Streams 20 MHz 40 MHz 80 MHz 160 MHz
1 86 Mbps 200 Mbps 433 Mbps 866 Mbps
2 173 Mbps 400 Mbps 866 Mbps 1.73 Gbps
3 288.9 Mbps 600 Mbps 1.3 Gbps 2.34 Gbps
4 346.7 Mbps 800 Mbps 1.73 Gbps 3.46 Gbps


Achieving higher data rates, however, comes at a cost: fewer available channels in the 5 GHz band. With 802.11a, there are a total of 24 non-overlapping channels available, but with 802.11ac, achieving the maximum data rate possible reduces that number to two for 80MHz and only one for 160 MHz wide channels.

Maximize Channel Availability

 

Table 3 - Available 802.11ac Channels

  Including DFS* Excluding DFS
Channel size US EUROPE US EUROPE
40 MHz 8 9 4 2
80 MHz 4 5 2 1
160 MHz 1 2 -- ---

* DFS = Dynamic Frequency Selection – for avoiding interference with Weather Radar

Achieving maximum data rates with 802.11ac can be an insurmountable “coverage” challenge for traditional Wi-Fi vendors (see Table 3) for whom it is imperative to have at least three non-overlapping channels for adequate pervasive coverage.  Meru’s technology is built with a single channel architecture and can maximize the performance and coverage of a 802.11ac-class solution, making Meru the de facto vendor able to deploy facility-wide solutions.

802.11ac Technical Overview

 

The other optimizations in 802.11ac also include:

  • Denser amplitude modulation – 256-QAM - four times denser than 802.11n further increasing the bit rate density achieved by 802.11ac. (Video)
  • More spatial streams - up to eight spatial streams, further increasing the data rate for each radio. (Note that first-generation silicon will support only three spatial streams.)
  • Beamforming to fortify RF connections – increases reliability of the AP/client link.
  • Multi-user MIMO – supports simultaneous transmissions to multiple clients and maximizes RF band utilization. Up to four distinct clients can receive data simultaneously from a single AP at full channel data rate.

Timetable for commercial availability of 802.11ac

Industry availability of commercial products will precede the ratification of the standard. The IEEE task group projects no functional changes to the specification, so Wi-Fi vendors are proceeding with plans to release products in mid-2013 (see below).

Because the 802.11ac standard has modified the RF physical and MAC layer specification, deployment of an 802.11ac-based network will require the purchase of new access points. The availability of 802.11ac, however, does not make 802.11n products obsolete because there remains a strong requirement for supporting 2.4GHz mobile devices. Enterprise deployments of 802.11ac will have to consider support for 2.4GHz.  

802.11ac deployment strategies

Purchase and integration of 802.11ac will involve three decision points:

  1. When to buy. 802.11n meets about 80-90% of the bandwidth demand of today’s mobile applications. In most cases, the on-boarding of applications like tele-presence and voice will trigger the decision to buy 802.11ac.
  2. Once a buy decision has been made, the next decision must be how to deploy 802.11ac to best provide for continued support of 2.4GHz devices. An 802.11ac deployment might mean a “forklift” replacement of older 802.11n equipment with dual-radio/dual-mode 802.11ac products or it might mean deploying an 802.11ac-only solution as an overlay to an existing 802.11n network. Either way, there will be a CAPEX factor to address.
  3. A decision must then be made on how pervasive is the need for Very High Throughput (VHT). One strategy would involve deploying VHT hotspots only where localized higher data rates or client density is required. Meru’s single channel architecture greatly simplifies this decision to extend VHT support pervasively throughout a facility.
Top Considerations when Upgrading to 802.11ac

The number of wirelessly connected devices is expected to grow from 10 billion to 212 billion by 2020.1 To support this explosion of devices onto our networks, the new 802.11ac Wi-Fi standard promises to deliver Gigabit Wi-Fi speeds and support for higher device densities. The increase to Gigabit speeds is accomplished in part by combining multiple Wi-Fi channels together. However, this can reduce the number of available unrestricted channels to two or fewer, constraining an IT administrator’s ability to use existing Wi-Fi access point deployment strategies. To deliver the full promise of the new standard, efficient use of Wi-Fi channels is critically important.

In the past, the competition leveraged the large number of available channels within the 802.11n standard by utilizing a minimum of three channels for enterprise-wide Wi-Fi coverage. With 802.11ac, this is no longer an easy option. Only Meru’s solution, with its unique single-channel, virtual-cell option within the MobileFLEX architecture can provide enterprise-wide coverage with just one channel. The architecture has been designed from day one to be the most channel-efficient Wi-Fi solution on the market. Only Meru can consistently deliver enterprise-wide Gigabit Wi-Fi speeds globally, providing Meru a significant advantage as enterprises transition to Gigabit Wi-Fi.

Mobility is an unstoppable force

There are almost as many mobile subscriptions as there are people in the world, according to the International Telecommunications Union.2 Yet we are only in the beginning stages of the mobility revolution. Within the next six years, more than 212 billion “Internet of Things” devices are expected to be wirelessly connected, up from 10 billion in 2013.3 The majority of American adults own smartphones, according to the Pew Research Center study and many have multiple mobile devices — a smartphone, a tablet, a laptop — that they use at the same time.4 In today’s mobile world, not only is Wi-Fi the preferred way to connect, but it is increasingly the only way to connect. Unfortunately, in the new Gigabit Wi-Fi world, there are fewer and fewer channels available to support all these devices. We are moving from double-digit channels with the 802.11n Wi-Fi standard to just one or two unrestricted channels with the new 802.11ac standard.5

Simplifying coverage

Other Wi-Fi vendors require a minimum of three non-overlapping channels to provide enterprise-wide Wi-Fi coverage. These vendors can use 80 MHz or 160 MHz channels only sparingly. In contrast, Meru only needs one channel for enterprise-wide coverage. With Meru’s single-channel, virtual-cell option within the MobileFLEX architecture, customers can deploy an enterprise-wide 802.11ac network that maximizes both performance and coverage.

The fastest 802.11ac solution

Vendors that are restricted to using smaller channel widths due to their need to use multiple channels for enterprise-wide AP deployments are limited to 600 Megabit speeds per radio or less. In contrast, Meru can deploy with wider channels, thus supporting the fastest Gigabit speeds per radio possible with the new 802.11ac Wi-Fi standard.

3x capacity and segmented applications

Meru needs only a single channel for enterprise-wide coverage which can be layered to deliver up to three times the capacity. With our unique channel layering capability, Meru can deliver the performance needed in high-density environments like lecture halls, convention centers, and stadiums. In addition, channel layering allows enterprises to physically separate applications at the radio frequency (RF) layer for the highest possible quality of service (QoS). As an example, hospitals can create a dedicated channel for life-critical applications such as patient monitoring and telemetry. Similarly, schools and universities can create a dedicated channel for online assessments.

Network in control

In the Wi-Fi standard, it is the client that monitors the availability of access points and decides when to roam from one access point to another. This can lead to inconsistent performance, as some clients roam too infrequently, resulting in a “sticky client,” while others can roam too aggressively and “ping pong” back and forth between multiple access points. Meru’s unique, standards-compliant wireless virtualization capability makes all the access points enterprise-wide appear as a single giant access point. This pulls the control away from the client and puts it back in the hands of the network infrastructure. In contrast to other vendors, where the client makes the roaming decision, Meru’s controllers hand off clients transparently from one access point to another based on context, providing maximum control over the user experience.

Great with 802.11ac Wave 1

With support for two 802.11ac radios and 80 MHz channels, Meru offers 2.5 times the capacity of other vendors when DFS channels are unavailable – which is often the case in dense urban environments, where airports and weather radar systems and other interfering sources prevent the use of DFS channels. Other major vendors are forced to recommend utilizing half the available 802.11ac Wave 1 channel widths in enterprise-wide deployments, limiting their ability to leverage the full power of 802.11ac.6

Even better with 802.11ac Wave 2

Meru’s technology differentiation becomes even more compelling with 802.11ac Wave 2, when only one 160 MHz channel is available. Vendors that only support multi-channel deployment architectures are limited to utilizing smaller channel widths in enterprise-wide deployments, which reduces their ability to capitalize on the higher speeds and capacity possible with 802.11ac Wave 2.7


  1. "Worldwide Internet of Things (IoT) 2013–2020 Forecast: Billions of Things, Trillions of Dollars" , IDC
  2. "Measuring the Information Society" , ITU
  3. "Worldwide Internet of Things (IoT) 2013–2020 Forecast: Billions of Things, Trillions of Dollars" , IDC
  4. "Internet & American Life Project," , Pew Research Center
  5. Non-DFS Channels
  6. Meru: 2 x 802.11ac @ 80Mhz = 2 x 1.300Gbps = 2.6Gbps
    Others: 1 x 802.11ac @ 40Mhz + 1 x 802.11n @ 40Mhz = 1 x 600Mbps + 1 x 450Mbps = 1.05Gbps
  7. Meru: 1 x 802.11ac @ 160Mhz = 1 x 2.600Gbps = 2.6Gbps
    Others: 1 x 802.11ac @ 40Mhz = 1 x 600Mbps = 0.6Gbps
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The fastest 802.11ac solutions in the industry

Meru has lead the WLAN industry in creating the AP832, the fastest 802.11ac wireless access point product, maximizing the promise of the standard. The product portfolio now consists of a set of three wireless access points addressing a broad spectrum of customer use cases. The AP832 is a three-stream 802.11ac access point for those who need the highest performance and client density solution. The AP822 is a cost- effective two-stream solution for mid-range performance requirements. Additionally, Meru offers the AP122, the industry’s first two-stream in-room wall plate format 802.11ac dual-radio access point. Keeping to our commitment, all these units are the fastest wireless access points in their class.

AP122


Application

Cost-effective, in-room gigabit performance solution for high-bandwidth wireless and mobile applications

Technology

Dual-radio, 2-stream 802.11ac wireless access point with Ethernet ports

Data Sheet
| Product Details

AP822


Application

High-density, cost-effective solution for high-bandwidth wireless and mobile applications

Technology

Dual-radio, two-stream 802.11ac wireless access point with optional internal or external antennas

Data Sheet
| Product Details

AP832


Application

High-density, high-diversity environments with high-bandwidth wireless and mobility applications

Technology

Dual-radio, three-stream 802.11ac wireless access point with either internal or external antennas

Data Sheet
| Product Details