Wi-Fi Aware

The ability for Wi-Fi enabled devices to automatically discover each other and understand each other’s public Wi-Fi offerings is a powerful enabler for point to point Wi-Fi connectivity. Standards based ad hoc point to point Wi-Fi connections are currently quite a manual arrangement and so have seen little usage. Attempts to initiate such connections using Bluetooth and NFC have lowered the hurdle, but pre-emptively discovered potential connections via Wi-Fi Aware will make it much easier.
As is very often the case the full potential of technology is unlocked by widely or ideally universal standards, so Wi-Fi Aware promises to create new possibilities.

Mobile network operators using unlicensed spectrum

Obviously MNOs using unlicensed spectrum disadvantages others operating in that spectrum. The freedom to setup wireless networks for distinct needs without the burden of licenses for its use is an important right that has and will continue to enable innovation and advances in wireless technology. If allowed, MNOs could easily subvert that resource.
The existence of the IEEE 802.19 Wireless Coexistence Working Group to addresses coexistence between wireless standards of unlicensed devices, and in particular its Coexistence in Unlicensed Bands Study Group, is late but welcome. Perhaps equipment working in the unlicensed spectrum will ultimately be required to conform to a coexistence protocol that can be mandated by the ETSI et al. Although and extra burden on those developing for unlicensed frequencies it would ultimately be a benefit as we move to higher utilisation.

Ofcom and 5G mobile services

From 16 January 2015 to 27 February 2015, Ofcom (regulator of spectrum in the UK) is asking “for stakeholder input on spectrum bands above 6 GHz that might be suitable for future mobile communication services.”
This is being broadly termed ‘5G mobile services’.
Although no standards yet exist and the technology is certainly inchoate, wireless technology develops quickly, so it is good to see Ofcom getting involved at this time.

Also on 12 March 2015 Ofcom is hosting a “debate to explore the impact of new mobile and wireless broadband technologies, including those underpinning 5G, on spectrum regulation and management.”

WiGig in mobile devices

Qualcomm has acquired Wilocity, a maker of chipsets for the 60 GHz wireless band – IEEE 802.11ad. Qualcomm chipsets for mobile devices are to be enabled in this band, so we should see rapid growth of 60 GHz (WiGig) inclusion in mobile devices.

Short range high throughput and out of band with existing WiFi, WiGig creates new opportunities. WiGig data transport from cheap low power small infrastructure equipment (see our thinking on Myrmidon access points) will be a great enabler for ubiquitous high throughput wireless connectivity. As consumer devices provide a rapid rollout of endpoints for WiGig so the ROI for this kind of access point becomes much better. Expect to see this new kind of access point coming to market in the short to medium term. A network built using them will make a form of ‘fog computing’ more viable, because high bandwidth wireless connectivity to proximate processing and storage services will have significant advantages over longer more contended network paths.

Dual band radios in mobile devices have been around for some time, and tri-band radios will be arriving soon. At some point it will become feasible to provide two or three concurrent radios in mobile devices with the obvious associated advantages. The question is when will such radio arrays arrive? Power consumption is probably the main constraint for this kind of connectivity. Battery technology is subject to intense research and we should expect impressive improvements to come to market soon. Nonetheless, concurrent multi-radio solutions need a rapid way to bring radios in and out of service to reduce power consumption.

MU-MIMO soon and trends

In April Qualcomm announced their forthcoming 802.11ac MU-MIMO chipsets. These include the QCA 9990 and QCA 9992 chipsets for business grade access points with 4 and 3 stream radios respectively. Their client device chipsets provide 1 and 2 streams. All these MU-MIMO chipsets provide up to 80 MHz channel width, not 160 MHz. Their highest link speed is then 1.73 Gbps on 4 stream access point and ‘home router’ chipsets, while their client device chipsets with 2 streams have a highest link speed of 867 Mbps. So, for an all Qualcomm setup the upper limits for access points and ‘home routers’ are more usefully considered as aggregate capacity limits, e.g. two 2 stream clients could in theory transfer at 1.73 Gbps. In practice of course it is more likely to be about half of that or less. As these chipsets were “expected to sample in the second quarter of 2014” we can expect them in the products in the second half of 2014, along with some of their competitors – Broadcom and Quantenna have made similar announcements.

With MU-MIMO access points can service multiple stations simultaneously, so the available streams can be more fully utilised. The most important effect of this is to effectively increase the capacity of the spectrum. Obviously this is good news for WLAN owners and managers who have spectrum operating around capacity. Although MU-MIMO does not make a connection faster than before, it does provide more uncontended air time to clients, so they should also feel the benefit as better transfer times.

As MU-MIMO is compute expensive we are going to see more PoE+ equipment. As more channels are available in the 5 GHz band, and they are being added to, it makes sense for access points with two or more radios with omnidirectional antennas to be deployed where spectrum is highly utilised. This will add further to power requirements so we may see a growing market for mid-span PoE+ injectors.

802.11ac and MU-MIMO is coming at a good time as expectations and use of WiFi are soaring; a trend that will continue as the Internet of Things and wearable devices gain traction. If rumours are correct, the ever growing bandwidth needs of static and moving images will soon be added to by the demands of holographic displays. Obviously with all this data aggregating over WiFi to Ethernet we need 10 GbE at a sensible price soon.

WiFi networks and crowdsourcing an IT strategy

In a recent survey 1 in 3 British workers say they rely on WiFi to do their jobs effectively, and 61% of those believe their home WiFi to be better than their workplace WiFi. That survey of 2,004 randomly selected British wireless-reliant UK workers aged 18+ was commissioned by Aerohive Networks – a US based maker of premium business grade WiFi equipment. Their report contains a number of observations on productivity problems in the workplace, with unreliable connectivity considered the most disruptive, power cuts as second, and ‘wireless temporarily down’ as third. Aerohive report that “Up to 40% have missed deadlines and opportunities at work due to poor [wireless] connectivity”. This negative experience of WiFi in the workplace relative to the home supports the widely held view that WiFi use in the workplace is led by employees, not by IT department strategists. From this report one might infer that WiFi connectivity in the workplace is behind the expectations and needs of some employees to work as productively as they would like.

Modern mobile working practices are more typical in younger people. It is probably significant that they have a more technologically aware mind-set, along with higher expectations of their working environment developed in technologically rich educational environments. Recently we upgraded WiFi in some student accommodation. While investigating issues with networks, two students in a common area both using WiFi were asked if they also used a wired connection. Only one of the two did, even though a laptop with a port for a wired connection was being used by the one that only used WiFi. Obviously this is a vanishingly small sample, but this scenario is typical, and there are two important points to draw from it. Firstly, both students were spending some time working in a communal area using WiFi, but that was their choice, not a requirement. Secondly, one did not even take the trouble to use a wired connection when it was available and provided a better service – the reason we were there. Mobility is at least in part about a more social and collaborative style of working. It allows people to take what they are doing with them. They are controlling the technology rather than the technology controlling them. In science fiction movies nothing is ever plugged in, everything is wireless because that is how we like to see ourselves, with freedom to move and in control of powerful technology. In problem scenarios in science fiction technology takes control, even if it is wielded by other people. Wireless connectivity then is an essential enabler of expectations in working practices, and currently wireless connectivity is dominated by WiFi.

A recent webinar by LogMeIn reported on their survey of almost 1400 IT and non-IT professionals globally concerning modern trends in IT that could be collectively described as crowdsourcing an IT strategy. They simplify their findings into four macro-IT trends:

Firstly – use of personal devices for business; the so called bring your own device (BYOD) trend. Employees chose the technology and IT departments provided WiFi connectivity. This was the start of significant employee contributions to the IT strategy, i.e. crowdsourcing the IT strategy.

Secondly – an empowered, connected, and mobile workforce. These employees (who as discussed above are generally younger) expect mobility and ubiquitous wireless connectivity. This group are probably the strongest drivers of WiFi expectations in the Aerohive Networks survey above.

Thirdly – applications sourced and managed by employees; the so called bring your own application (BYOA) trend. Employees report they do not always feel the need to seek the approval of the IT department, particularly to address problems localised to their small groups and themselves. This has resulted in a strong move away from enterprise grade software to the cloud ‘app’ based approach (cloud based processing and storage) which has perceived advantages described in terms like convenience, ease of use, agility, speed, less hassle, and flexibility. However, this piecemeal approach has no overarching strategy and little or no appreciation of broader consequences.

Fourthly – business data is increasingly in the cloud. A major advantage of the cloud is location anonymity, but that can also be a concern for some data.

IT professionals see the consequence of these four macro trends as a less secure and controlled IT world, with 42% expecting this trend to continue, and 35% expecting it to remain at about the same level. The main concern of 54% of IT professionals is a lack of security of business data in the cloud. The survey also indicated that 29% of IT departments monitor and modulate use of apps, accepting its inevitability but trying to make use of its advantages; 39% broadly ignore it, not yet knowing how to react; and 30% are actively suppressing use of apps not sanctioned by the IT department. This last reaction is despite strong anecdotal evidence that employee productivity is improved by these four trends.

We can see from these two surveys that IT strategies in the workplace are now partially emerging from employee decisions. At this time no coherent response has been established among IT professionals to crowdsourcing of IT strategy. However it is accepted that a strong WiFi network is a key enabling technology for the modern mobile working practices expected by an empowered, connected, and mobile workforce. Likely the way forward will be found in technologies being developed to modulate these trends so as to gain the best from them while minimising problems. Certainly, while it still possible the old arrangement of IT departments totally controlling IT use and strategy in the workplace are looking increasingly outdated and likely to hold back productivity.

‘Bring your own access’ will accelerate the trend for IT strategy crowdsourcing. Personally controlled mobile Internet connectivity can circumvent corporate Internet connectivity, so IT departments will then be unaware of the data moving in and out of the business. As data prices fall, coverage and speeds improve, and employees become more technologically enabled, this trend will accelerate.

8x8x8 MU-MIMO WiFi in 2015

Quantenna says they plan to release 8x8x8 MU-MIMO chipsets in 2015
This will be a very important development for anyone owning WiFi networks and of course WLAN/LAN professionals.
8 stream MU-MIMO can provide very high aggregate throughput to the LAN, making more efficient use of the WiFi infrastructure but requiring a 10 GbE LAN to make full use of it.

The significance of the ‘MU’ in 802.11ac MU-MIMO

Firstly, what is the ‘MU’ feature in 802.11ac MU-MIMO? Put simply it allows multiple Wi-Fi client devices (e.g. mobile phones, tablets, and laptops) to exchange data with an access point radio, in parallel. Previously only one Wi-Fi client device at a time could exchange data with an access point radio. An important consequence of this is that the aggregate throughput of access points can spend longer at higher levels and so make more efficient use of network resources. Another consequence is that traffic analysis will be more difficult when there are multiple simultaneous talkers.

The number of Wi-Fi client devices that can exchange data simultaneously with an access point radio is limited by the number of spatial streams that each supports. The 802.11ac amendment to the 802.11 standard allows for radios with up to eight spatial streams, although only recently have four stream MU-MIMO processors become available. Each spatial stream is a distinct stream of data that requires an antenna of its own linked to one radio. A connection between an access point and a Wi-Fi client device will use one or more streams. In practical terms this means a four stream 802.11ac processor with MU-MIMO in an access point can communicate in parallel with four single stream client devices, or two single stream client devices and one two stream client device, or two client devices each using two streams, or of course one four stream client device.

At this time a typical 802.11ac setup may use an 80 MHz channel width and an 800 ns guard interval, with connections perhaps achieving MCS 7. If that setup were fully MU-MIMO enabled it would then have a theoretical aggregate throughput of 4*292.5 Mbps i.e. 1.17 Gbps. Out of interest I performed a test as I wrote this in very good RF conditions using a Sony Xperia Z Ultra and Samsung Galaxy NotePRO 12.2 connected to D-Link DAP-2695. I used them for no other reason than they happen to be sitting on the next desk and are all are very current. All of these are 802.11ac devices, but not MU-MIMO. The Sony device achieved a link speed of 325 Mbps with RSSI at -42 dBm; it delivered 205.7 Mbps up and 207.95 Mbps down. The Samsung device achieved a link speed of 866 Mbps with RSSI also at -42 dBm; it delivered 208.87 Mbps up and 413.89 Mbps down. These were the best figures from among a handful of tests on each client device. Some test results achieved only half of these rates or less, but most were similar. These links are clearly 80 MHz, 400 ns, MCS 7 and MCS 9 for the Sony and Samsung respectively, with one and two streams respectively. Anyway, if these devices were MU-MIMO then my best aggregate download throughput for two Xperia and one NotePRO (for example) would be 2*207.95 + 413.89 = 829.79 Mbps. Add a client on a 600 Mbps 2.4 GHz radio and we can see it is possible for an access point to make full use a GbE link. The theoretical throughput of GbE is 118660598 data bytes per second (about 949 Mbps) using a 1460 data bytes Maximum Segment Size in a normal Ethernet frame of 1518 bytes containing a Maximum Transmission Unit (MTU) of 1500 bytes. Using a 9K MTU improves this to about 123916800 data bytes per second i.e. about 991 Mbps. In practice of course these theoretical GbE maximums cannot be achieved, and Wi-Fi transfer rates are likely to be about half of the link speed.

Let us consider how multiple SSIDs relate to this ‘MU’ feature. An access point radio operates on one logical channel at a time. In fact that logical channel may be composed of multiple contiguous channels or discontinuous ‘bonded’ channels that behave as one large channel. These techniques increase the amount of spectrum used by a radio for a logical channel and so its bandwidth. They do not provide distinct parallel streams of data. As SSIDs are configured to a band and thence a radio, so they will all share the same logical channel of their radio. Consequently all SSID traffic has to take a turn on their radio’s configured logical channel, unless that radio is MU-MIMO enabled. In which case SSID traffic might travel over one or more spatial streams, depending on Wi-Fi client device MU-MIMO capability, and so could travel in parallel with other SSID traffic. So, SSIDs provide no innate transmission parallelism; that can only come from MU-MIMO enabled 802.11ac radios.

The balance of wired and wireless

Recently I installed a 4G LTE router in a site where there is a poor wired Internet service with no plans for improvement, but a choice of proximate 4G LTE base stations. The resulting wireless throughput is better, the service more reliable, and the prospect of further improvements immanent – partly because of the increasing competition between the wireless Internet service providers (WISPs) offering 4G. Apparently the wired infrastructure is not economically viable to upgrade according to its ISP. This is surprising statement given that the area is very densely populated with consumers and wired infrastructure. Perhaps what they mean is not enough disgruntled customers are leaving for 4G to justify spend on upgrading their service yet. This is not the first area I have come across with that attitude by an ISP. The first time I was told this was also in a build-up area, but it had fewer consumers and more businesses that are probably paying for leased lines anyway, so it was easier to see why there. Anyway, this attitude made me wonder where it is economically viable to put in at least fibre to the cabinet. Obviously the WISP base stations that serve this recent site need to aggregate a lot of data, and at least one of them has no wireless carrier antennas, so I suspect it is using fibre for backhaul. I think this is a case where wired infrastructure can more easily make money. It has the throughput advantage (at the moment) that can justify the cost of digging in a heavily developed area with strong property laws. I expect ISPs to continue to cede customers to WISPs and wired infrastructure to further retrench and focus on highly aggregated throughput.

Now suppose that some clever researcher finds some scrap of information intrinsic in electromagnetic radiation that allows distinct transceivers to be identified, or even just groups of them. This would make a dramatic difference to wireless communication because spectrum becomes less contended. In fact something like that has already been announced in the shape of pCells. I hope for and expect more innovations of this kind. When they arrive they will have a profound effect on wireless communication and wires will retrench further.