Peering Over the Horizon

The recent growth of personal mobile devices has been nothing short of phenomenal.  A large part of what makes these devices so enticing is the universal mobile connectivity provided by Wifi, in which the capacity to deliver video and other bandwidth-hungry content is available.  Once relegated to the home, the Enterprise campus and the occasional “hot spot”, Wifi is blossoming into a full-fledged, publicly-accessible, ubiquitously deployed utility.  While not yet as fully integrated or seamless as the cellular networks, public Wifi can be found just about anywhere.  Airport Wifi solutions, restaurant Wifi solutions, convention Wifi solutions, stadium Wifi solutions; it’s all happening and it’s everywhere!

Unlike cellular deployments and expansion which are highly planned and controlled by a few carriers, Wifi growth has been an asynchronous, bottoms up approach from numerous uncoordinated individuals and groups relying on a shared, unlicensed spectrum.  With more and more mobile Wifi devices being deployed daily coupled with emerging demands for HD content, greater Wifi capacity will be required.  So where will the capacity be found to meet our seemingly insatiable demand?

Not betting the farm on new frequency spectrum allocations happening anytime soon, there are three standards looming on the horizon promising to fill the void.

The first is 802.11ac.  This effort targets increasing Wifi data rates up to ten times or about 1Gbps.  Operating in the 5 GHz band, it achieves this capacity increase through high-density modulation of up to 256 QAM across 160 MHz channels while leveraging up to eight MIMO spatial streams and multi-use MIMO.  Taking advantage of recent improvements in signal processing technology, 802.11ac is proving to be not only faster but more robust with better resistance to multipath fading.  This will mean significant improvements for airport Wifi solutions, stadium Wi-Fi solutions and other venues looking to deliver HD content in densely populated environments.  The finalization of this standard is expected in late 2012 with full production deployments in 2015.

The second effort, 802.11ad is being developed to deliver even higher data rates from 6 Gbps to 60 Gbps.  To achieve such high rates of throughput, developers are looking “upstairs” to the unlicensed green field spectrum at 60 GHz.  Unfortunately, the laws of physics come into play, restricting the distances in which such high bandwidths can be delivered.  While limited to 20 feet or so, this technology still promises significant advantage to restaurant Wifi solutions, convention Wifi solutions and other closely populated venues.

The third effort, known as White-Fi, is 802.11af.  Readers of this blog will be familiar with its strategy of using “white space”, the unused spectrum or guard bands between existing TV channels.  While not offering the high data rates promised by 802.11ac and 802.11ad, White-Fi’s strategic advantage is delivering additional capacity at much further distances.  This is due to the characteristics of the UHF frequency spectrum used by 802.11af which enables beyond line of sight communications not possible in the existing 2.4 GHz and 5 GHZ unlicensed microwave spectrum.

Wifi is rapidly becoming a ubiquitous public utility.  While new efforts to increase capacity are forthcoming, the challenge is to develop new technology to allow the integration, coordination and control necessary to merge these disparate Wifi communities into one seamless virtual public network.


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