Wi-Fi Goes Carrier-Class
ORLANDO — Wi-Fi is growing up. Standards bodies, silicon makers and equipment vendors are working hard to improve the reliability, capacity, security and mobility of Wi-Fi networks and devices. Cable operators are well-positioned to benefit from these advances, noted the speakers at yesterday’s SCTE Cable-Tec Expo workshop “Wi-Fi Lessons Learned and Where It’s Going.”
Stuart Hoggan, principal architect/Security at CableLabs noted technology improvements are making Wi-Fi much more service provider friendly or “carrier grade.” These advances include improvements in:
>> Roaming,
>> Security and
>> Automatic network discovery and selection.
As in the wireless world, roaming agreements between services providers will allow a subscriber of one service provider to access the Wi-Fi network of another. Therefore, roaming will require an inter-operator interface to provide subscriber authentication and support billing, noted Hoggan. By supporting roaming, network providers have the potential for a wider Wi-Fi footprint and the ability to offer new such new services as wireless data offload.
Hoggan also noted the industry is seeing improvements in Wi-Fi security. Security is critical to a carrier-class service to provide data privacy via encryption and authentication to ensure users are connected to a trusted network, and no theft of service occurs.
“WPA2 enterprise is well-suited to this,” said Hoggan. There are issues, however, because many legacy devices don’t support WPA2 or don’t support all of its features. It’s also complex to configure, which could be a barrier to adoption. “Cable operators may have to support both open SSIDs and secure SSIDs for a long time,” until more devices have an easier way to implement security, he added.
In addition, auto network discovery is essential to a carrier-class Wi-Fi service, and the WFA Hotspot 2.0 protocol is tackling this challenge. Hotspot 2.0 allows clients to discover roaming relationship, access point capability and network load connections, and help them select the best access point to connect to, Hoggan explained. Such seamless and automatic network discovery will lead to higher adoption and an improved user experience.
Carrier-Grade Wi-Fi Is Real
So what is carrier-grade Wi-Fi? For in-home distribution, Hal Roberts, systems architect at Calix, defines it as the ability to support four HD videos (or 40 Mbps minimum throughput) plus VoIP plus data with 90 percent coverage of 90 percent of homes at low error rates.
Enhancements such as wider channels – 40 megahertz enabled by 802.11n and 80 megahertz coming with 802.11ac – as well as multiple input multiple output (MIMO) spatial multiplexing supplies the increased throughput, he said. Innovations like beam forming, which uses multiple antennas to “point” the signal to clients, also increases the signal strength to devices, thus making them more reliable and increasing throughput.
Will this really work? Roberts says yes. Calix obtained silicon from three vendors and used their reference designs to build devices to test throughputs. It set up an in-home benchmark test in a three-story, 3,700-sq.ft. home, with the access point placed in the lowest level. Test results showed these minimum rates:
>> 2×2 @ 2.4 GHz = 35 Mbps (zero “no communication” errors)
>> 2×2 @ 5 GHz = 14 Mbps (two no-communication errors)
>> 3×3 @ 5 GHz = 48 Mbps (carrier class)
>> 4×4 @ 5 GHz = 255 Mbps (carrier class)
“The improvements are real. It maybe doubtful you’ll get 255 Mbps, but you will certainly get a huge improvement,” Roberts explained.
What will cable operators do with this carrier-class service? Husnain Bajwa, vice president/Product Marketing at Ericsson, sees potential deployment scenarios in direct sales, wholesale and operator-managed services to enterprises. These include indoor applications in cafes, malls, airports and retail stores; indoor/outdoor applications at universities, hospitals, and marinas; stadiums; and such outdoor applications as city centers, mass transit and parks.
— Jennifer Whalen
