Wi-Fi spreads its wings

The performance of Wi-Fi has increased hugely over the past five years and it is now enabling more than just connectivity, as network owners add new applications such as voice over Wi-Fi, location and proximity services and potentially become a platform for M2M and IoT applications. James Atkinson reports

Wi-Fi spreads its wings

Wi-Fi technology is rapidly becoming the world’s most ubiquitous form of wireless technology in the home, enterprise, and in public spaces. It is also increasingly being embraced by service providers including cable, fixed line and mobile network operators.

This is in part due to the fact that the technology has evolved to match Ethernet speeds and throughput, and in many cases the products are of carrier-grade quality with the arrival of the 802.11ac standard, which provides gigabit speeds. And this perhaps is leading to a different focus.

‘Wi-Fi is now very efficient in terms of performance – with the caveat that it is deployed properly. It can now provide enough bandwidth and speed to handle most uses cases. As a result there is now less focus on the technology design elements and more on the added-value services you can bring to the Wi-Fi,’ says Bruce Miller, VP of product marketing at Xirrus.

Matthew Gast, director of product management at Aerohive Networks, agrees. ‘Wi-Fi is fast enough for most uses cases now, with some exceptions, such as sporting arenas. It mostly delivers a very good service, especially at short distances – there is nothing the same in terms of price, performance and capability. Now it’s about making Wi-Fi adaptable to your needs.’

However, Miller says: ‘The mobile carriers have a very disciplined approach in terms of testing and network design to make sure that the user experience is really good to try to stop subscribers churning to another carrier. Typically, you do not have that competitive issue with Wi-Fi, so I think we need to up the ante and adopt a more carrier-type mentality to network design, self-testing and monitoring of the wireless environment.’ 

802.11ac standard
The 802.11ac Wi-Fi standard (which uses the 5GHz unlicensed band) is now the prevailing Wi-Fi technology. In its latest annual report, From 2016 to 5G, the Wireless Broadband Alliance (WBA) notes that 802.11ac products now dominate new shipments as of the third quarter of 2015. 802.11ac Wave 1 products came to market in 2014 and now account for 40% of access point (AP) shipments globally.

The second half of 2015 saw the first 802.11ac Wave 2 products coming to market. According to the WBA summary, Wave 2 of the standard brings wider channels than Wave 1 (up from 80MHz to 160MHz) plus other speed boosters such as multi-user MIMO, up to 256 QAM modulation and up to four spatial streams. These enhancements boost peak data rates from 433.3Mbps per spatial stream (1.2Gbps total) for Wave 1, to an aggregate 6.93Gbps for Wave 2 (given ideal spectrum circumstances).

Serving the enterprise
In the enterprise space, key considerations have centred on providing scalability, handling increased densities of simultaneous users, making networks easy to implement and manage for customers with little IT or RF expertise, using the network to improve business processes and efficiency – and where feasible, monetising the Wi-Fi network by introducing new services that provide revenue streams.

Two other important areas that have attracted a lot of attention from Wi-Fi vendors are handling the BYOD phenomenon and enabling mobile access to the network anywhere, anytime, anyhow.

At a briefing in October this year, Dominic Orr, CEO of Aruba (now an HP company), said the company’s aim is to provide a Cloud-first, mobile-first, approach to networking. In combination with HP, Aruba wants to provide ‘agile application delivery from the data centre to the mobile edge’.

‘We need an open system as the features of each application are going to be different, so this requires a composable per application computing infrastructure, where you release the necessary resources to handle the demands of a particular application – addressing priority, timing, bandwidth, etc,’ says Orr.

He argues that the new digital workplace is one dominated by wireless devices, and networks have to get smarter to deal with this. ‘We need to be constantly aware of who the users are, what apps need priority, and what resources need to be marshalled to deal with them.

‘We need to have the intelligence to decide what traffic needs to go through immediately and what can wait; who are the VIPs in the room? We have to preferentially disappoint – you know which apps or which people you must give preference to,’ says Orr.

Miller agrees, saying: ‘You can have multiple networks on top of each other, which you can divide into: a critical network for the business; a BYOD network that doesn’t have such high-priority access; and maybe an M2M industrial network with sensors and that kind of device.
They might be on the same network, but they are essentially segregated according to what they are and what they need to do, so you provide multiple services over the same infrastructure.’

Scalability issues
Scalability is being addressed in a number of ways, but virtualisation is proving a compelling approach for Ruckus Wireless. ‘I feel Wi-Fi is a bit ahead of the game with NFV/SDN,’ says Dave Wright, advanced technologist at Ruckus. ‘We’ve been doing this for some time where the controller tells the APs to do edge forwarding or centralised forwarding.’

A year ago, Ruckus unveiled its Virtual SmartZone controller – a virtual control plane, which encapsulates key network functions in software that can run on standard hardware. In November this year, it separated out the data plane in the shape of its Virtual SmartZone Data Plane (vSZ-D) – a further move into NFV/SDN territory. The vSZ-D distributes the workload across multiple systems requiring only a single controller and vSZ-D deployments at remote sites.

Wright explains the thinking. ‘We’ve redistributed the workflow between the APs and the controller. Before, most of the MAC layer processing and data had been offloaded to the controller, but as we scaled to 10,000s of access points (APs) it became untenable to shunt everything back to the controller to do all the processing.

‘So, we moved some of the processing back to the APs, which meant investment in more SON and radio resource management, to ensure that only necessary data or information is going back to the controller. Due to that and the way we architected our controller, we are able to support 10,000 APs on a single platform and 30,000 APs on a cluster – with 300,000 devices.’

Data analytics
Wi-Fi is also very good at providing big data analytics. ‘We can see what the users our doing on the network, so our customers can now collect the kinds of data on their end users that they’ve never had access to before, which they can mine for useful insights,’ says Aerohive’s Matthew Gast. Location-based and proximity services are one such outcome of this data.

A number of Wi-Fi vendors have improved the accuracy of Wi-Fi by combining it with beacons. ‘It depends how granular you need to be and what range you need to operate in,’ says Wright. ‘Bluetooth beacons are very granular, but you need a lot of them.’

Gast says: ‘Combined Wi-Fi and beacon location accuracy allows you do something different. It depends on the scale you want – in building, floor or room or even
in what part of the room or store. Each step requires a different level of measurement, so as you make more detailed information available, that enables you to do different things and provide different types of services.’

Aruba’s Orr argues that this kind of technology enhances mobile engagement, which needs to be simple and Cloud managed with a rich SDK for application developers. ‘We now have the opportunity to use the network to see who has come into a shop. We can see that a certain customer comes into a particular coffee shop every Monday to Friday between 8.00 and 8.15am, but at the weekend goes to a branch somewhere else for two hours.

‘A company could use the data to increase the rent in one location, because they can prove the footfall is 40% greater in this branch than that one. It can also use this data to push information, vouchers, or a loyalty card to the customer – this is mobile engagement,’ says Orr.

Gast says he has heard of a rail system where the train conductor is fitted with a beacon. ‘It doesn’t have to be you moving closer to the beacon to activate a location-based application. Instead, something else is moving closer to you. Only wireless technology can enable this kind of application.’

Wi-Fi Calling
It is these kinds of services that enable Wi-Fi network owners to do more than just provide connectivity – they can monetise it as well. Wi-Fi calling or voice over Wi-Fi can also provide an opportunity to monetise – perhaps not in mature markets with good cellular coverage where the user expectation would be for free access. But in less developed regions, many users might be prepared to pay a bit for VoWiFi if they cannot access cellular coverage.

But there are other reasons for operators to embrace VoWiFi. Ruckus’s Wright observes: ‘What is really fascinating is that the carriers saw what happened to SMS and they know they cannot afford to lose the voice experience. As a result we are seeing a pretty aggressive movement to embrace carrier VoWiFi services.

‘What this means is that Wi-Fi is becoming part of global voice services, something that is critical to operators who don’t want to lose that service. They want to maintain that customer connection as strongly as possible,’ says Wright.

The next billion
Looking ahead, Wright points out that Google, Microsoft, Apple, and Facebook are all thinking about how to provide Internet access to the next two billion potential users who are not already connected. But cellular solutions are cost prohibitive for a lot of the world’s population, so Wi-Fi networks might be the answer.

Gast says the role of the Wi-Fi vendor is evolving. ‘Marketing departments are about to overtake IT departments on what they spend on IT. Enterprises have to drive business value, so they need help from organisations who understand what they are doing better.

‘The core of what we do at Aerohive is to provide connectivity, but what is important is to help the customer to understand how to use that better and drive efficiencies and provide added-value services.’

Xirrus’ Miller adds a warning. ‘We are seeing so many changes in this dynamic market. There are new devices all the time; who knows what Samsung or Apple might come up with. That means the infrastructure must be able to adapt and cope with the unexpected because the customer only buys new Wi-Fi every five years. Future proofing is all important therefore. They need to buy something that is flexible that can cope with whatever the future might bring.’

What’s next in Wi-Fi technology?
802.11ad, or WiGig, operates in the 60 GHz band and supports multi-gigabit speeds, but has a very limited range because of power limitations in that spectrum. Good for in-room media, small cell backhaul, fast connection to peripherals. Available in 2015.

802.11ah will use ISM spectrum (868 MHz in Europe, 900 MHz in North America) and is designed to support long range Wi-Fi and Internet of Things applications including smart cities and rural access. It will compete with low power wide area network (LPWAN) standards such as Sigfox using the same bands. IEEE expected to ratify in 2016.

802.11af will enable Wi-Fi to use TV white spaces spectrum. The WBA notes that ‘the viability of the TVWS is still hotly debated, especially outside the US’. IEEE expected to ratify in 2016.

802.11ax aims to deliver gigabit speeds to the end user (rather than gigabit access points), using MIMO-OFDA signalling, also a possible technology for 5G. This combines MIMO antenna arrays with multiple access OFDM modulation. Good for venues and dense hotzones. It should be ratified in 2019.

Where can Wi-Fi find more spectrum?
The 2.4GHz unlicensed band is already heavily congested, so the arrival of 802.11ac technology in the 5GHz unlicensed band has been much needed. However, it too is filling up. The WBA’s From 2016 to 5G report identifies the main sources before 2020 as:

• Additional 5 GHz frequencies for conventional Wi-Fi/802.11ac. Most of these will be made possible by new spectrum sharing techniques, which make it more practical to have Wi-Fi (and other license-exempt technologies) coexist with licensed incumbents such as radar.
• Shared spectrum options such as TV White Space and 3.5 GHz (especially in North America, where the FCC proposes three tiers of access).
• Expansion into bands currently used by short-range devices and others, notably 863-868 MHz, with the 802.11ah extension.
• Expansion into 60 GHz spectrum courtesy of the WiGig standard (802.11ad).
• The 802.11ax effort is already investigating potential new licence-exempt or shared usage bands between 1 GHz and 6 GHz. Some of these will be the topic of debate at the World Radio Conference in November 2015, and its successor in 2019 (which will examine 5G spectrum allocations).

LTE in unlicensed spectrum
The proposal to enable the use of 4G LTE cellular in the 5GHz band has naturally caused some controversy in the Wi-Fi community. There are three approaches.

LTE-Unlicensed (LTE-U)
LTE-U is the most divisive because it does not implement ‘listen before talk’ (LBT) mechanisms to avoid interference with other signals such as Wi-Fi. This technology is already part of the 3GPP standards, but could only be used in countries such as the US and Japan, which do not mandate LBT in the 5 GHz band.

LTE-LAA (Licensed Assisted Access)
LTE-LAA uses the 5 GHz spectrum for supplemental downlink, boosting the capacity of a host network in licensed frequencies. Unlike LTE-U it does implement LBT to ensure no disruption to Wi-Fi. ‘It is still somewhat up in the air, but we are cautiously optimistic about where it is heading,’ says Ruckus’ Dave Wright.

LTELWA (Wi-Fi Link Access)
LTELWA splits the LTE data payload and tunnels some traffic over Wi-Fi. In effect it creates a tunnel for LTE traffic inside 802.11ac frames. It accesses the spectrum like Wi-Fi does and looks like Wi-Fi to other Wi-Fi networks in the same channel.

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