Monday, 10 June 2013

802.11ad - Just for Home Cinema...Right?

One of the things I love about Twitter is that once in a while you stumble across something that completely shifts your view of the world. I spotted this little nugget (posted by @wifichef) a couple of days ago, which made me significantly re-assess my view of the application of 802.11ad technology:
"A deeper dive in to High Capacity WLANs: http://t.co/L6kcx5oMI9"
Expecting another deep dive in to 802.11n high density WLANs (...small cell sizes, using 5GHz, band steering, disabling lower speeds etc.) I clicked through the link to see if I could find any new information. However, I was completely surprised to find myself looking at a whitepaper discussing the merits of 802.11ad! In fact, it actually highlighted the disadvantages of a traditional 'legacy' WiFi network - this had me hooked :)

I must admit that I had dismissed 802.11ad (which uses the 60GHz band) as a niche technology that I'd probably hardly ever see in the Enterprise environments that I tend to work in. (I must admit to having only a superficial knowledge of the 802.11ad standard though). After all, what use is a wireless technology that can only travel a few feet, particularly when you have a building of maybe hundreds or thousands of people? How could we ever design usable WiFi networks with cell sizes that small!? You might see it on some consumer-grade wireless routers, perhaps for movie streaming in the home. Beyond that...nah, I just didn't see  it taking off.

But, after reviewing this whitepaper from Wilocity, I had to pause and re-assess my view of 802.11ad. It details testing done in high density client environments using 802.11ad-capable latops. They posted some very impressive link speed and SNR results for a 'high density' of 802.11ad stations in close proximity. This was achieved by deploying a number of 802.11ad laptops, each of which had an 802.11ad wireless docking station next to it on the desk. Each desk had an equal number of laptops and docking stations around the edges of the desk (as you might expect to see in a typical office).



My first reaction was: "Well why would you do that? If each docking station is cabled anyhow, why not just pull the network cable out of the docking station and connect it in to the laptop!?". But, after some thought, I started to consider how this technology might advance in the future... 

It looks like we only have per-laptop 802.11ad docking stations at the moment (which obviously doesn't save you much in cabling, assuming each docking station is cabled). But,  perhaps wireless equipment vendors might be able to manufacture per-desk 802.11ad access points in the future, for just the users occupying that desk? If that could be coupled with fast transition to existing 802.11n/ac office-wide networks, then as users roam about the office, they could hop between 802.11n/ac & 802.11ad networks. This would provide high speed 802.11ad at a user's desk, with lower speed 802.11n/ac as they use the traditional office wide network whilst moving between desks and rooms.

These super-small cells could make the planning of high-capacity wireless networks much easier in office-type environments. Just put an AP on each desk, together with a token blanket of traditional (ceiling-mounted) WiFi coverage to provide slower-speed transit connectivity as users move around. That would certainly make HD wireless surveying a lot more straightforward!

I have no idea how much of this will be technically possible, but I could certainly see the attraction of this type of super-small cell. It is much more akin to the provision of desktop hubs or switches that regular wired network engineers could get their head around, making support and planning much easier than traditional WiFi networks. This would obviously require more cable drops around the office, but there may be some environments where the additional cabling is worth the trade-off for the additional capacity and ease of deployment.

It is going to be fascinating to see how 802.11ad evolves and whether it could introduce yet another paradigm shift around WiFi networking.