More and more aspects of home and work applications are moving to an online streaming model. Consequently, wireless internet technology needs to evolve to meet our increasing usage of high-definition 4K streaming and cloud-based services.
The Institute of Electricians and Electronics Engineers (IEEE) addresses the challenges posed by our growing demands for internet services with the publication of the 802.11ax: High Efficiency WLANs certification.
First, wireless networks will become an increasingly dense network environment, as more access points are installed to expand network coverage and improve transmission rates. Second, the internet’s evolution towards high-definition audio and video content, as well as cloud-based services, will increase the demand for throughput rates in the coming years.
Many people today already carry more than one internet connected device, such as a smartphone, smartwatch and/or internet tablet, and the number of devices that are carried is expected to increase. The forecast for the number of network-connected devices is almost 31 billion devices worldwide in 2020, and more than double that by 2025.
Allowing large numbers of additional devices to connect to an existing network would result in congestion, and a necessity for organisations to deploy more access points to ensure a satisfactory service, leading to an increased density of access points.
In such a dense environment, interference issues can arise, which in turn increase the packet error rate – the degree to which errors are encountered during data transmission over a network – and reduce the number of concurrent transmissions in a given area by preventing neighbouring WLANs from accessing the channel.
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In scenarios such as these, it can become a challenge to deploy, optimise and coordinate large numbers of access points. This is especially true where an internet service provider (ISP) offers internet access to large numbers of people in a comparatively small area; “802.11ax capabilities will bring improved performance to home, multi-tenant apartment and office deployments, and enterprise and public venue applications,” says Dorothy Stanley, IEEE 802.11 working group chair.
In such cases, intelligent access point coordination can improve spatial reuse, and the use of an efficient medium access protocol could support many simultaneous connections. It could be argued that 802.11ax has been designed for the internet of things (IoT), where multiple devices require regular internet access, without loss of connection, in order to remain functional.
“The lower latency characteristics will enable new use-cases including IoT and control systems,” says Stanley.
802.11ax will be a new type of WLAN, which is designed to operate in the existing 2.4 GHz and 5 GHz bands, as well as incorporating additional bands between 1 and 7 GHz as they become available.
Though the nominal data rate of 802.11ax devices is 37% higher than IEEE 802.11ac, the new amendment is expected to be able to achieve a fourfold increase to the average user throughput rate. This is due to a more efficient spectrum utilisation and the use of MU-OFDMA (Multi-User Orthogonal Frequency Division Multiple Access) technology.
According to the developers of 802.11ax, interactive and high-definition video – such as multi-party video conferencing and virtual reality – is anticipated to dominate future internet usage. Both of these will require several gigabits of throughput rate.
Multimedia internet usage
Internet usage is also increasingly moving towards a multimedia format, with audio and video content. Furthermore, file storage, management and synchronisation with the cloud is becoming the standard for content management and generation systems.
Based on predicted future scenarios and expected use-cases, IEEE 802.11ax incorporates three key amendments:
- Coexistence: WLANs need to coexist with other wireless networks that also operate in the same environment and with licensed devices.
- Higher throughput: Improving both the system and user throughput requires a more efficient use of channel resources.
- Energy efficiency: The increasing demands on access points will require improved low-power hardware architecture as well as low-power functionalities.
Alongside this, 802.11ax allows for backwards compatibility with devices that are certified for previous versions of the standards. Whilst there will be a loss of efficiency and functionality with connecting devices of differing certifications, backwards compatibility must be maintained in order to ensure their primary function – connectivity.
To achieve these objectives, IEEE 802.11ax introduces new functionality to wireless devices:
- Spatial reuse: The combined use of CSMA/CA (Carrier-Sense Multiple Access with Collision Avoidance), a conservative CCA (Clear Channel Assessment) and a high transmit rate can allow for limited spatial reuse in certain scenarios.
- Temporal efficiency: As CSMA/CA functionalities can shorten the time that a node spends transmitting data every time it accesses a channel, IEE 802.11ax includes several solutions to mitigate this reduction.
- Spectrum sharing: Unplanned deployment of WLANs results in a fragmented spectrum occupancy and causes inefficiencies and interference from neighbouring WLANs, thus dynamic clouding and MU-OFDMA are introduced.
- Multiple antennas: As well as downlink MU-MIMO (Multi User – Multiple Input and Multiple Output), there will now be an uplink MU-MIMO, allowing for – as the name suggests –multiple users to both download and upload data concurrently.
All of this combines to offer performance gains through improved spatial reuse and a wider spectrum utilisation. “802.11ax is a way more efficient use of the spectrum – sub-carrier divisions in a channel allow you to put more data through,” explains Blaz Vavpetic, CTO of iPass a global aggregator of wireless networks.
Some may view 802.11ax as a competitor to 5G mobile communications networks. However, it would be more accurate to describe it as a complementary network. Each has their own unique advantages, which operate best in different environments.
“Everybody is riding the 5G hype train right now, but when you break it down in to the characteristics of density, efficiency and power/performance, then 802.11ax checks all those boxes,” says Vavpetic.
That said, there are specific use-cases where one is more suitable than the other. For example, 5G networks operating in the higher spectrum may be best for high bandwidth and low latency use cases, such as in line-of-sight applications. However, 5G is also susceptible to interference at higher frequencies.
“The minute you start putting those devices in motion and they start experiencing disruptive objects in the radio frequency environment, then 5G service starts to falter,” says Vavpetic.
Wi-Fi 6, which includes 802.11ax, will pave the way for WPA3 adoption. WPA3 brings improved security to previously open and unencrypted Wi-Fi networks. Whereas before, where many Wi-Fi hotspots were open and unencrypted, WPA allows their interface to be encrypted using 256-bit AES, which is inherently more secure.
“As a service provider, we aggregate approximately 65,000,000 hot spots around the world and use VPN to provide air interface encryption; but in a world where everyone is Wi-Fi 6, you get the benefit of AES encryption,” says Vavpetic.
One of the key advantages of 802.11ax is that it is not a technology swap, but a technology upgrade. In order to take full advantage of 802.11ax functionality, companies do not need to replace their existing network infrastructure, or change how they manage their service. It would simply work on top of the existing wireless network structure.
Blaz Vavpetic, iPass
Given the improved functionality of 802.11ax, many companies may wish to bring their device strategy forward in order to acquire 802.11ax devices sooner. Whilst in certain scenarios this may be an understandable hardware strategy, it would generally be recommended for an organisation to maintain their existing hardware schedule, but to upgrade their access points to 802.11ax devices when they come to end of their lifecycle.
“Nobody is going to truncate their life-cycle to do the upgrade,” says Vavpetic. “But as they come through, and their budget allows, they will be taking 802.11ax upgrades.”
Of course, the full advantage of 802.11ax networks will not be felt until the devices on the network are 802.11ax certified. However, this new Wi-Fi standard has experienced significant challenges and delays, due to the previous two versions of the draft standard being rejected, before it was passed by the IEEE committee in July 2018.
Once the standard has been ratified, networks will start to upgrade to 802.11ax as the certified devices proliferate into the enterprise environment. “Ratification is expected in 1-2Q 2020, with products shipping in 2018/2019,” says Stanley.
With this in mind, service providers do not necessarily need to accelerate their investment cycles, as 802.11ax compliant devices will not be there from the beginning. Instead, there will be a trickle-through proliferation of the standard, which will see a gradual dissemination of technology.
Ultimately, 802.11ax provides the most benefits in dense environments that have a high number of active, network-connected devices entering the environment at the same time. It is in these environments that the improved spatial efficiency and multiple-user access points will be fully taken advantage of.
“802.11ax will help Wi-Fi be prominent in the next generation of wireless services,” concludes Vavpetic.