Is 802.11ad the Ultimate Cable Replacement?

At the Consumer Electronics Show early last month in Las Vegas, a very unglamorous announcement was made by the IEEE: The organization officially signed off on the 802.11ad standard.Though making what to many is a bookkeeping-type announcement at a show filled with shiny gadgetry is a recipe not to be noticed, the advance of 802.11ad is a major step forward in the evolution of the 802.11 WiFi family. And, though products are a year or two down the road, it is a spec that should be watched very carefully by cable operators.The bottom line is that 802.11ad is almost certain to become a useful tool in home networking applications. "We see this not only on the computing side, but also the home entertainment side for storage and docking," said Srinivas Pattamatta, the director for computing at Qualcomm Atheros (NASDAQ:QCOM). "We can imagine for cable operators who want HDMI quality with low latency that this we be the right technology."Each incremental advance of the 802.11 family has taken a fairly similar path: Each sends data a bit faster and a bit longer distance than its processor. This has held true through at least five variants of the standard, and will for the latest, which is 802.11ac. While this family has taken shape and expanded, the ecosystem and other interested parties have developed a generic set of tools such as beam forming and Multiple In Multiple Out (MIMO) antennas. The 802.11ad standard is similar - and significantly different. What it shares is the use of the generic toolset. Where it branches off from previous 802.11 is its use of the extremely high 60 GHz range. This means that the use case is turned on its head. 802.11ad, which will be marketed as WiGig, is a very-short-distances technique capable of sending data at the breakneck speed of 7 Gbps.Stephen Palm, the senior technical director for Broadcom (NASDAQ:BRCM), pointed out the fundamental need to support mobile devices - which is driving interest in 802.11ac - isn't the main rationale for 802.11ad. It is more of a cable replacement technology to tidy up the "rat's nest" effect of multiple wires connecting set-tops, TV sets, DVRs, etc. "802.11ac is very big in operator plans because of the changing demographic of the viewers," Palm said. "That change in the demographic - going from wired to wireless - doesn’t apply to [the usecase for] "ad.'"802.11ad never will be a complete replacement for wires because it is a line-of-sight technology that doesn't propagate through walls. However, dual- and tri-band chips already will enable a session to agilely move between WiFi standards. Qualcomm and Wilocity have released the reference design for such a chip.Thus, for instance, a user transferring a high-definition movie 3 feet from a home gateway can start out doing so via WiGig. As he or she walks out the door, the transfer would agilely shift to 802.11ac or whatever other "flavor" of WiFi in the chip. For more stationary uses - sending data from a set-top or gateway across the room to a big screen TV, for example - 802.11ad may be the only version necessary.This clearly is a long term endeavor. Jay Fausch, Alcatel-Lucent's (Euronext Paris, NYSE:ALU) senior director for customer marketing, suggests that the industry is in a good position. While residential gateways are generating a lot of current interest, they remain a future technology for most operators - as the new WiFi protocols are. This is another way of saying that this all could work out quite nicely. "The timing for the maturation of 802.11ac and ad and the rollout of next-generation residential gateways is reasonably well aligned," he said. "MSOs should be talking about the roadmap."At the end of the day, cable operators will have a number of 802.11 technologies to choose from. Hal Roberts, a systems engineer and architect for Calix (NYSE:CALX), suggested another role for 802.11ad. In many instances, 802.11ac or the earlier versions of the protocol will suffice for home networks. At some point, however, 802.11ad - operating at that isolated frequency band - may be an offload option when the more common WiFi frequencies become too crowded. "It could take much of the burden off 'ac' when the day rolls around when 'ac' is more mature," he said. "Think of it as a safety value for 'ac.'"In the bigger picture, cable operators should understand that many of the advances that are being made in what may appear to be different areas can benefit them - and their competitors. The physical laws and design goals are the same across all telecommunications disciplines, said John Chapman, the CTO of Cisco's (NASDAQ:CSCO) Cable Access Business Unit and a Cisco Fellow. In this sense, convergence has already occurred. The interest of operators in 802.11ac and 802.11ad - a family of protocols that wasn’t designed with cable in mind but from which it will benefit - is an example of this. "Cable guys are feeding from the same trough as others," Chapman said. "If it can be built for WiFi, it can be built for cable."Carl Weinschenk is the Senior Editor for Broadband Technology Report. Contact him at [email protected].