AirTies can finally talk openly about Sky-Q hybrid mesh

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WiFi symbol in highlight concrete wall.

Bulent Celebi, the ebullient chairman of AirTies Wireless Networks, has been talking to us about proprietary mesh networks and powerline as a spare backhaul option in WiFi for so long, that it’s hard to imagine that we have never written about it. But it has taken this long for someone to buy into the concept and for the product to be completed for a live implementation and readied for launch.

The fact that the someone is Sky, one of the two largest pay TV operators in Europe, will make everyone want to understand just what it has achieved and how this system works on its new Sky Q set top.

The significance is that when you add client steering, a technology that AirTies has already announced, this is a genuine solution to the bad apple problem, without resorting to something dramatic. Other market players have suggested that you simply prioritize the TVs in the home over the tablets and if tablet bandwidth usage gets too high, you simply cut it off.

The whole 802.11AC wave 2 was all about adding MU (multi user) MIMO to WiFi. This is a complex mathematical process to aim multiple beams of radio at up to four devices at once. If one of these ungratefully takes too much capacity – creates a bad apple – then only one beam is lost, and the other 75% capacity of the chips can continue to operate at full speed.

But this technology is as yet untried at any operator, and is more suited say some, to really high density environments such as conference halls and stadiums.

What the AirTies solution does is quite complex, but bear with us. First, all of its product lines jump from channel to channel frequently, taking samples of what each WiFi channel condition is like, before it decides to occupy that channel. This way it ensures that it always has a clean, empty part of the WiFi spectrum to work in. For AirTies that’s old hat, but most equipment vendors still do not do this.

It then uses 5GHz WiFi as backhaul for a mesh, preferably making your home gateway and every TV in your home into an Access Point in its own right, which talk to one another, transferring and organizing traffic.

Each node in the mesh will tend to speak in 2.4 GHz to handsets and tablets, which for the most part is the only WiFi which is used inside these devices. In an operator market, the big devices such as smart TVs and set tops, will tend to tap into the plentiful bandwidth in 5.0 GHz, for the heavy lifting of 4K TV streams. But in a Single User WiFi chip, the processor looks first at one device and serves it, then at the next and so on, rather like a timesharing processor, before rotating back to the first one again. If it can keep up with their respective data demands, like this, sequentially, then no problem. But if one of the devices becomes greedy, and takes longer to quench its data thirst, then the others are left waiting.

This is the dreaded bad apple problem and as we say most attempts at solving it are based around cutting off the rogue portable device in order to preserve the data for fixed devices. The reasons a tablet, which only needs say 10 Mbps to get a video stream, can cause this problem is because when the connection gets unreliable, the WiFi drops down to a less efficient, but more robust form of data encoding, perhaps from 64QAM to QPSK, and so it takes far longer to deliver the same stream. And the reason this happens is because these devices move, and their antennas change position, and they get further away, and require the signal to go through more obstacles.

Now if that device happens to use a 5.0 GHz WiFi chip, it begins to drag down the performance of the entire mesh which is relying on 5.0 GHz for talking from the home gateway to each TV set or set top. And when that happens the TV signal can fall apart.

Because of this AirTies adds two further ideas. First it steers each client device to the Access Point in the home which has the best signal for it, and remember every TV or set top or home gateway or network storage device is an AP. This means the bad apple happens less often, and as we said, mostly on a 2.4 GHz radio. But when it happens on a 5.0 GHz radio the system still recovers by opting to use powerline connections between some of the fast boxes, for all, or part, of the data transfer.

So some frames could come over the air and some over the HomePlug AV2 powerline, but they all get there on time. This results in a revolutionary performance improvement that Sky has been testing for about 3 years.

“Today it is capable of 5 HD streams simultaneously,” Celebi told us “and allows you to record 4 others.” And his client’s press release quote shows what Sky thinks, “Working with AirTies has helped us create an amazing new customer experience across screens with Fluid Viewing, as well as take the Sky experience to the next level by enabling Sky Broadband customers to turn all their Sky Q boxes into smart hotspots,” said Andrew Olson, Director of New Products, Sky.

Celebi says this is the very first installation of this type anywhere in the world, and it is the culmination of over 12 years or work at AirTies, a company that he helped form in 2004, moving back from Silicon Valley to his native Istanbul, Turkey, to kick start it.

The system is perfectly capable of carrying multiple streams of 4K he assures us. Apart from the overall robustness, which means that coaxial fixed line connection no longer needs to be made between two devices in the home, this means that transcoding can be done on the signal that comes down from the satellite. So exceptionally high quality video can arrive at your smart phone and tablet, as good when it arrives at your TV set, (if your tablet screen is up to it) and this creates that Fluid Viewing that Sky is talking about. The viewing can be moved from device to device, always travelling over a combination of WiFi and powerline.

The set top is built around Broadcom chips, as is the WiFi, while the powerline chips come from Qualcomm Atheros.

“But aren’t you worried that the set top maker will simply copy the idea?” we asked AirTies. “Well in this case it is the old Amstrad arm that Sky bought to make its own set tops. So our deal is in the form of a technology license which the operator holds.”

This is a great solution for most of Europe, and it works really well for Sky, because it is a satellite TV provider, which has broadband capacity in the UK, but not in Germany or Italy, so it prefers not to send its signal over the internet. Its TV Everywhere service, Sky Go, which does travel over the internet, as does Sky Now, its separate pay TV OTT service. But these do not get close to the quality of video which comes from Sky Q, Celebi insists. And of course, it means Sky doesn’t need two routes into the home – satellite and the internet.

We know from previous discussions with both AirTies and others, that the power lines inside homes are not homogeneous around Europe and while it may work well in the UK, perhaps some of the central European countries would offer more problems, because the electrical cable can be substandard.

Also in the USA and China, while it might work, a similar combination of MoCA and WiFi might also work well. The upper speeds of MoCA are faster than even the latest HomePlug AV2 powerline, with MIMO.

In fact, there is a standard, the IEEE 1905.1 which allows transfers of a signal from WiFi to HomePlug to Ethernet to MoCA. We asked if the Sky Q system used it? “There are two reasons why we did not use 1905,” said Celebi, “first it is not a complete point to multipoint standard, only point to point, and secondly because our algorithms need to know the condition of traffic in every part of the network and 1905 does not facilitate a unified two-way interface. And Sky said ‘Who cares’.”

Another feature of the Sky Q system is allowing a user to download a program to a tablet or phone, and play it at the same quality, away from the home. This is presumably facilitated by the NDS part of Cisco which has always provided conditional access to Sky. However Inside Secure has the Sky Go contracts at Sky, so it may have come from there. Essentially the device must have an app which has key protection, hiding encryption keys from the iOS and Android operating systems in order to do this.

There have been two schools of thought on how to move forward on WiFi and one of them is that more and more antennas are needed on a single device, while AirTies has always made the point that upgrading the WiFi chip inside a device to a full Access Point, is a better way, because of its meshing capabilities. Celebi added, “We think that some other vendors and operators are coming around to our way of thinking, and will start to look at multiple APs in the home. Cablelabs has a project looking at this.”

But is HomePlug AV2 man enough for the job. Sometimes interference on the powerline can be considerable, dropping traffic from 200 Mbps down to 20 Mbps. “Yes, but you have to remember this is a mesh, not just in WiFi, but in powerline, so if we have part of the network poorly performing, it will automatically reach the device through another powerline route. And adding a node or trying a different power socket will almost always permanently solve any problem.”

Now that it has landed a tier 1 account with this technology many pay TV operators will be wanting to take a peek and see if this is appropriate for them.

While AT&T is known to use Quantenna WiFi chips, it initially had WiFi just for speaking to another TV, one that you can put in the garden. It still doesn’t use the WiFi to transcode out to other devices, and neither does DirecTV. “We have multiple tier 1 trials going on,” said Celebi, “both in Europe and the US, but we can’t name any names.”

We promptly bet him that AirTies would receive an offer it could not refuse to acquire the business from one of the major equipment vendors before the end of 2016. “No comment” he said.

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