Presentation at IEEE 802.11 portends an inevitable future Wi-Fi that will utilize ultrawideband frequencies
In the world of wireless communications the term UWB is often mistaken for the WiMedia or ECMA wireless standard or the unsuccessful Wireless USB standard championed by Intel in 2005. UWB actually stands for ultrawideband. The FCC defines ultrawideband as any radio transmission that utilizes at least 500MHz of contiguous radio spectrum. WiMedia and Wireless USB are examples of UWB, but there are other examples of UWB including the PHYs supported in the recently published 802.15.6 Body Area Network standard (a pulse based UWB wave form) and the WiGig 60GHz standard.
At the recent IEEE meeting held in San Diego on July 17th, there was an evening session to discuss the possibility of utilizing the unlicensed ultrawideband frequencies from 6-9GHz as a future extension of Wi-Fi. These presentations were not proposing to adopt the earlier WiMedia efforts as an extension of Wi-Fi, rather they discussed the technical and marketing issues of extending the Wi-Fi frequency range to the 6-9GHz ultrawideband frequencies. Though 802.11ac is only just coming to market the 5GHz spectrum is expected to become quickly over crowded, much like 2.4GHz is overcrowded today. There are many reasons for this, including the fact that AC uses very wide channels that use a great deal of spectrum for speed, the fact that more and more tablets, smartphones and HDTVs will use AC for video thereby clogging the spectrum, and the possibility that Wi-Fi Direct will become popular thus using up even more spectrum. Based on all these market dynamics, and the fact that it takes many years to develop extensions of an international standard, the time is not far off when Wi-Fi will need more spectrum; that is where UWB frequencies come in. As a result of the FCC’s original ruling making UWB frequencies are available in the USA and most major countries. The common frequency bands across these countries generally are from 6GHz to 9GHz and are authorized in countries such as the USA, Canada, UK, the EU, China, Korea, Japan, Russia and many others. The transmit power permitted in this frequency band is small compared to what is authorized today for Wi-Fi, yet by utilizing greater than 500MHz of spectrum the in-room data rates are similar to what 802.11ac can achieve. Moreover, an added benefit of using 500MHz of spectrum is that power efficiency can be improved, which is ideal for mobile in-room applications such as smartphone, gaming controller and tablet connectivity.
Alereon spoke at the IEEE meeting, presenting real measured data on our chips that operate in the 6 – 9GHz frequency bands achieving data rates on the desktop up to 1Gbps, from a couch to an HDTV of many 100s of Mbps, and across a room sufficiently to transmit compressed 1080P video at a higher throughput and lower latency than today’s Wi-Fi video streaming links. The presentation went on to project that with some proposed enhancements in technology that are similar to new techniques found in 802.11ac, that data rates of 4 or 8Gbps could be achieved on the desktop or in close proximity for applications such as photo sharing, and many hundreds of Mbps could be transmitted very robustly in an average room. Other presentations essentially proposed the IEEE should consider forming a group to consider the development of an “AC+” extension for in room applications, such as Wi-Fi Direct or other personal area connectivity or wireless video applications. The proposal for an AC+ was not meant to detract from the already completed 802.11ad efforts that use ultrawideband frequencies up around 60GHz to extend Wi-Fi. Rather the proposal was made to increase the spectrum capacity of Wi-Fi for in-room applications while focusing infrastructure applications in the existing 5GHz range. Finally, it should be noted that not all countries derive the same benefit from extending 802.11ac to the new 5GHz frequencies as others. In particular China, the world’s most populated country with the highest urban densities and the highest sales of smartphones also has 80% less available spectrum at 5GHz than most other countries. So this proposal to utilize ultrawideband spectrum should look particularly interesting to Chinese constituencies.
The IEEE works in mysterious ways often fraught with non-technical considerations based on the interests of large and influential companies. Like many good ideas, it is likely to take time for this idea to gestate. That said, to me it seems this idea has a certain element of inevitability to it. For companies like Alereon, which have familiarity with UWB frequencies and have built chips that can make highly useful wireless connections in these unlicensed frequency bands, we know how valuable this spectrum can be. For other companies however, there is a fear of the unknown. However the continued consumer demand for new applications with more video and more wireless connectivity, in the constant pursuit of a Life without Wires™, makes it inevitable that the IEEE will someday utilize UWB spectrum. There simply isn’t any other unlicensed spectrum available.
Let me know your thoughts. Thanks for reading. — EB
