In-Depth

Wireless world: The increasing WiFi burden

phone_holding_lifestyle_picGrowth in devices that can play back video means that more demands than ever are being placed on domestic WiFi networks. With 4K UHD TV and VR on the way, the problem is only going to get worse. Stuart Thomson looks at possible solutions.

Fixed-line multi-play operators have long supported in-home WiFi as part of their broadband offering and, more recently, in-home WiFi has been used to deliver TV everywhere services. Now, with the launch of advanced TV offerings, including complete line-ups of HD – and increasingly also 4K Ultra HD – channels, supplied to an ever-expanding number of devices in the home, the burden on WiFi is becoming greater.

The issue is particularly pressing for service providers as problems with WiFi connectivity account for a huge proportion of calls to their customer care centres and ultimately for people churning from their services.

Charles Cheevers, chief technology officer, customer premises equipment, at technology provider Arris, says that operators must build in-home networks that can cope with the expected growth in bandwidth consumption driven by the proliferation of connected devices and the popularity of ultra-high-bandwidth applications such as virtual reality gaming.

While video streaming, even of 4K UHD TV content, along with a migration of QAM video to IP will ultimately only require about 25Mbps within the home, Cheevers foresees four tipping points that could dramatically increase in-home bandwidth demand.

One is the switch to UHD video over IP, leading to a fourfold growth in bandwidth. A second is uptake of wirelessly connected 8K TVs, thin enough to be wall-mounted, that will likely be wirelessly connected, avoiding the need for an ungainly set-top box to be mounted alongside them. Together with existing applications, this could require 170Mbps.

The other two tipping points relate to HD and UHD virtual reality applications. The addition of HD virtual reality could require 350Mbps while full UHD virtual reality could lead to bandwidth demand over 10 times that required today for IP video – perhaps 675Mbps.

Growth in demand for these high-bandwidth applications will go hand-in-hand with growth in the number of connected devices – tablets, smartphones, wireless cameras, and other devices – all of them consuming video wirelessly.

WiFi architecture

With a growing need to move beyond best-effort WiFi and support the delivery of multiple streams of video to multiple devices, operators are still working out how to deliver quality assurance for in-home video distribution.

For Bülent Çelebi, CEO of wireless networking specialist AirTies, operators have to move beyond straightforward solutions such as deploying modems that work in both 2.4GHz and 5GHz bands – the latter is able to deliver higher throughput and is less prone to interference, but is effective only over shorter distances – which he says is “not good enough” to solve the problem. Deploying higher-specification devices such as DOCSIS gateways with 8×8 channel configurations will be insufficient, he says.

“Operators are investigating what path to go down,” says Çelebi. However, until now few operators have deployed advanced WiFi systems. Single access points situated under the staircase or out of sight in a cupboard remain the most common basis for delivering in-home connectivity – a situation that technologists in the field believe will ultimately be unsustainable.

Brick walls inside homes immediately compromise the bandwidth available from WiFi. In the US, where houses are often made of wood, this is less of a problem, but even in areas where wood construction is predominant, tiling in bathrooms and heavier exterior walls can present challenges. In Europe, where brick and concrete are more widely used, the challenges are even more pronounced.

The situation in the US is also exacerbated, says Çelebi, by the proliferation in the number of devices now being used to consume video within the home. “OTT streaming is not that big in Europe yet but it is in the US,” he says.

Taking a basic mobile device upstairs in a home will reduce the performance of that device in playing back video.

The only clear solution, says Çelebi, is to build multiple access points in the home. “In particular, you have mobile devices and people moving around inside the house, away from the main WiFi access points – this creates a perfect storm,” he says. To solve the problem operators are now deploying a minimum of two access points and often as many as six, he says. “The good news is you can keep on adding them until you get coverage everywhere,” he says. For Sky’s advanced TV deployment, Sky Q, in which AirTies was involved, the UK pay TV operator “turned all its set-top boxes to smart access points” enabling homes with multiple TVs to distribute video around the home wirelessly.

While delivering the in-home network fully through wireless is the most cost-efficient way to go, some operators have successfully passed the cost of connecting access points via hybrid deployments, using Powerline or Multimedia over Cable Access (MoCA) as an in-home backbone, to their consumers. “You have cable operators in the US charging US$10 a month for premium WiFi, so they are making incremental money from it,” says Çelebi. Operators can also provide an in-home network to subscribers who trade up to higher broadband offerings as an incentive to do so.

Hybrid solutions

Çelebi says that a ‘pure WiFi’ solution can currently provide about 200Mbps around the house, which, he says, “at this point is more than good enough for multiple UHD streams”. Further down the line, there may be a more pressing need for hybrid solutions, he says. However, not all of these are equal. While plumbing in Ethernet cabling is clearly the best solution available, relying on Powerline is much less reliable, he claims, because of the huge variations in bandwidth available from different sockets and the difficulty of predicting available bandwidth. For this reason, he says, Powerline is best used as a complementary backbone solution to wireless, adding in capacity to what is already available.

For Çelebi, using a combination of the different technologies available should enable operators to stay ahead of the development of the broadband pipe into the home and changes in consumer expectations about available bandwidth.

Wireless technology itself will get smarter and will make more use of available spectrum to improve bandwidth and performance, says Çelebi. “The next wave of innovation will focus on making use of available spectrum,” he says. The 802.11ax standard represents the next generation of the WiFi standard and will help. 802.11ax make use of time division multiplexing techniques to ensure optimal use of the available spectrum, delivering a likely fourfold improvement in bandwidth compared with the current 802.11ac standard. Use of this technology can go hand in hand with technical innovations such as AirTies’ client steering, says Çelebi, enabling slower client devices to be kept out of various bands so that they don’t drive down the speed of the network.

Most agree that operators will have to invest significantly in their in-home networks. Arris’ Cheevers postulates a typical current home network based on a single WiFi access point using 2.4GHz spectrum, probably poorly located and which does not connect to low-power Internet of Things devices.

Cheevers says that the ‘Gigabit home’ could involve a primary gateway – possibly an 8×8 device, and 4×4 extenders to enhance coverage, using both 2.4GHz and 5GHz spectrum. The in-home backbone could be wireless, or wired, based on Ethernet or MoCA.

The need to connect IoT devices will lead to the addition of low-power radios, possibly based on the Zigbee/Thread protocol. There is also potential in the future for the use of 60GHz spectrum – part of what is known as millimetre wave band – which can deliver very high bandwidth over very short distances.

To feed the network, the backbone could be built on a hybrid solution involving existing cabling, new cabling or via a pure wireless solution, says Cheevers.

“We try to leverage what we have. There is coax which is more prevalent in the US. You could have a 10Gbps coax network that could feed these [extenders] without having to rewire,” he says. “Powerline is another option but it struggles to give you multi-Gigabit speeds due to interference and so on. Structured cabling is another option.” Regarding the latter, Cheevers says that there is considerable interest in the effort to create a standard, dubbed 802.3bz, that would deliver speeds over Ethernet cabling of 2.5Gbps to 5Gbps, requiring a less heavy investment than 10GbE. An alternative, he says, is to use a pure wireless solution, perhaps based on the 802.11ax standard delivered over a Mesh or 60GHz network.

The future in-home network may require creativity from service providers in persuading customers to pay extra for services and to position gateway devices more centrally in the home. The two things are not unconnected. Operators have been busy working on designs that consumers would be happier to display in the open rather than hide under the staircase, but, as Cheevers points out, “the cost is not insubstantial”.

For Steve Johnson, regional director for northern Europe at WiFi technology specialist Ruckus Wireless, service providers have typically sought to deploy WiFi using low-cost consumer technology platforms that provide best-effort coverage and bandwidth, with many areas within the home not covered. The use of multiple devices simultaneously is causing problems and this is only going to get worse as more consumers use more devices at the same time. “That is leading to a requirement for enterprise-class technology as against consumer-level technology,” says Johnson. “Operators are willing to invest.”

For Johnson, the shared nature of WiFi means that growth in the number of internet-connected devices in the home is the key challenge. He says security of WiFi is also becoming increasingly important.

Number of devices

In-home networks are also increasingly having to cope with applications that require huge bandwidth and bandwidth at irregular intervals, but for Johnson this is less of an issue than the number of devices.

“However, the biggest challenge is operator bandwidth,” he says, arguing that the bandwidth delivered to the home is generally more of a bottleneck than the WiFi network itself. Within the home, he says, the capability of technologies such as Ruckus’ own Beamflex enables the wireless signal to be focused, permitting more devices to be connected, generally without the need for additional access points in small-to-average sized homes.

“Nothing frightens an operator more than moving everything to WiFi because [poor quality WiFi] is the thing that can make customers churn fastest,” says Cheevers. Video transmission requires a very high degree of reliability. The general rule, he says, is that you need to provide four times the bandwidth to the home that you want to guarantee for a particular service such as 4K UHD TV. He says that operators may try to persuade consumers to pay, directly or indirectly, for differentiated bandwidth, with premium services being privileged over other services.

“If you buy a pay-per-view event and your kids are doing whatever they want elsewhere, then nothing will stop the pay-per-view because you are paying for that to be the priority and the other [uses] can be throttled a bit,” he says. “Free VoD will have a lower priority than paid for VoD – we think there are dynamics in the market that will allow us to prioritise services.”

The delivery of data to an ever-growing number of devices in the home is not without its challenges. “When you start adding different applications together you have the equivalent of an enterprise network in the home,” says AirTies’ Çelebi. “However consumers don’t have their own IT department and they do have size and cost constraints.”

Çelebi says that AirTies is involved in field trials that feature 25-30 devices feeding off the same network. As the Internet of Things begins to take off, things are “only going to get worse”, he says. In addition to the proliferation of devices, consumers are also becoming more interested in ultra-bandwidth-hungry applications such as virtual reality gaming, requiring huge amounts of capacity.

While a number of technologists believe the time has come for operators to seriously consider investing more heavily in multiple in-home access points and extenders, others argue that there is still a lot that could be done to make existing deployments work better.

Alan Marks, senior solutions marketing manager at Nokia, says that changing the physical architecture of the WiFi network only makes sense if operators know what is going on inside the network. To enable a better understanding of the in-home network, cable operators have for the last couple of years been deploying TR-069-enabled devices. TR-069 is a technical specification that enables remote management of end-user devices. More recently, operators have also started deploying TR-181, a data model-enabling specification that works in conjunction with more recent TR-069-enabled devices.

“WiFi-related home networking issues are the top drivers of calls to customer care centres. What we’ve seen in the cable segment is an adoption of TR-069 remote management capabilities. Operators have been rolling out TR-069-enabled gateways that give them a more robust data model and better remote management on the LAN side of things,” says Marks. “Another thing they do after that is look more closely at the data collection and analytics piece – how to use analytics capabilities across the whole infrastructure.”

Marks concedes that there is a cost associated with putting TR-181 capability in gateways but points out that this will enable operators to configure the in-home network more efficiently, including by showing subscribers how to optimise their networks without the need for an expensive truck roll. Analytics can help the operator and subscriber figure out what needs to be done, including whether there is a need for a physical reconfiguration of the network he says.

Meanwhile, Jonathan Nevo Junowicz, business development manager for the Residential Clean Air project at Cisco, maintains that currently “no-one is optimising in-home WiFi”, which accounts for the vast bulk of calls to care centres. Typically these calls, which are already expensive to the operator and frustrating to the customer, result in a router being (expensively) replaced by the operator.

According to Nevo Junowicz, three out of five routers returned for refurbishment are found to be in perfect condition. The problem is interference of the signal, with neighbouring WiFi clouds and indoor and outdoor units causing each other problems. The problem is even greater, he says, in the 5GHz spectrum than in the 2.4GHz range.

According to Cisco’s own analysis, over half of installed residential gateways are tuned to a non-optimal channel both in the 2.4GHz an the 5GHz spectrum ranges. One in 10 gateways are transmitting on too much power, leading them to interfere with a further 15% of gateways located nearby. Overall, the density of residential gateways, small-to-medium business WiFi installations and outdoor access points are contributing to the problem.

For Nevo Junowicz, operators would do well to more effectively manage their indoor networks to minimise the interference problem rather than invest in new hardware.

To help solve this problem, Cisco has proposed what it describes as a Residential Clean Air cloud-based offering, designed to manage the in-home network remotely to avoid interference issues arising. He says that trials have shown that once a network was properly configured, traffic across that network increased by 30%.

“The service provider, without changing the architecture of these networks, with a small client [download] can deliver the correct configuration for any given consumer premises equipment,” he says. “The ‘last meter’ problem has not been solved and optimised and most vendors have not taken care of it.” Nevo Junowicz claims that Cisco will be able to differentiate between homes that simply need a reconfiguration of their existing equipment and those that require additional extenders and access points to deliver the desired bandwidth. “This is the first time that the service provider has been able to see inside the home.”

For Nevo Junowicz, cellular technologies contribute to the problems, with Bluetooth and microwave technologies active in the 2.4GHz range and LTE-U promising to colonise large sections of the 5GHz spectrum. He says that the crunch facing operators as they look to a future involving more devices hanging on the WiFi network, consuming every greater amounts of bandwidth, could be deferred significantly by solving the interference problems that exist in the home today.

Arris’ Cheevers points out that legacy networks could also pose problems. He says that 802.11ax’s ability to deliver a step change in in-home bandwidth could be compromised to some extent if it has to coexist with 802.11ac. “802.11ax is four times as efficient as 802.11ac. That’s great. It gives you 400Mbps instead of 100Mbps so you have plenty of room for virtual reality and IP video services. The problem is when you mix 802.11ax with 802.11ac. It is not quite as inefficient as ‘all 802.11ac’ but there will be collisions.” This is a problem that will only be worked out over time as 802.11ac devices are phased out.

Cellular technologies could also potentially cause problems, although the extent to which this is likely to be true is contentious. In the US, the telecoms regulator, the FCC, has allowed operators to use unlicensed 5GHz spectrum for LTE as LTE-Unlicensed (LTE-U), which has given rise to concerns that it could seriously compromise the efficiency of WiFi networks using the same spectrum. In Europe, where regulators have insisted on a ‘listen-before-talk’ protocol to avoid this issue, the 3GPP Group has created ‘Licence Assisted Access’, whereby LTE signals will only use the spectrum in time slots when the WiFi traffic is not using it.

Cellular technology

While cellular technology could theoretically compromise WiFi performance, the fact that the same companies that operate cellular networks generally also support WiFi makes this less likely in practice.

There seems to be a consensus that cellular will not emerge as a substitute for WiFi. Further down the line there is ultra high-bandwidth 5G mobile to look forward to. For in-home networking, however, WiFi is likely to reign supreme and there will be no place for current or future cellular technologies in delivering in-home connectivity.

AirTies’ Çelebi thinks WiFi will be able to provide the capacity necessary to support the emerging range of devices and applications that consumers are likely to want, and does not believe that cellular technology will have a significant role in delivering connectivity in the home. Operators will be able to manage the WiFi-based in-home network to support the devices that rely on it, he says: “The capability is there so why bring in another standard and technology? I don’t see any reason for that.”

For Ruckus’s Johnson, WiFi is only going to become more, rather than less, important, with cellular technologies continuing to be challenged to provide effective in-building coverage.

Implementing a major role for WiFi outside the home is more challenging. Cable operators  in particular have investigated a ‘WiFi first’ approach to delivering mobile data – and voice – to their subscribers, both inside and outside the home. WiFi First can mean a number of things, however. The use of in-home networks to deliver wider public access through partitioning and multiple SSIDs has been widely discussed and implemented by a number of operators, but it meets with mixed reactions from technologists.

Çelebi, for example, is extremely sceptical about the wider potential of the use of partitioned home networks to deliver public WiFi. “The first problem is that these access points are in poor places [for public WiFi] such as the study or garage. The WiFi signal has to cut across an exterior wall which might be concrete, and then someone has to walk in front of the house and make a connection – and it could be a poor connection,” he says. Such a solution will, he says, only be effective if operators use multiple frequencies and client steering with multiple access points close to the street.

With over 50% of mobile traffic estimated to originate from inside the home, it could make more sense to focus on ensuring seamless roaming between cellular and WiFi networks once people go inside.

In any case, while mobile companies have been effective in pressing for more and more spectrum for wireless networks, WiFi has emerged as the clear technology of choice for most things that consumers want to do in the digital home.

“The World – led by Apple and Google – is going ‘WiFi First’,” says Nevo Junowicz, who adds that, just as SMS revenues were decimated by the arrival of the iPhone and all that followed, so video revenues are now running towards Netflix and voice revenues are heading to Facebook.

WiFi is clearly the technology of choice to enable the digital home to reach its full potential. But this means that the fixed-line broadband service operators that provide that network as part of their overall offering of multiplay services – including TV – are going to have their work cut out to make sure that the coming wave of high bandwidth applications using these networks does not result in their call centres being swamped by angry customers, leading to a dramatic shift upwards in churn.

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