An Express Lane For Wi-Fi

By Paul Kruczkowski, Editor

The desire to wirelessly move increasing amounts of data quickly around the home and office is asking more of Wi-Fi than the technology is currently capable of providing. The newest IEEE 802.11ac standard only provides for about 1 GBit/s performance for multi-station WLAN throughput and 500 Mbit/s maximum single link speed — a far cry from the multi-gigabit speeds needed for HD video and data sharing/backup applications. In addition, demand for Wi-Fi enabled devices continues to grow, straining Wi-Fi's limited bandwidth and increasing the opportunities for interference. At the same time, the emergence of thinner, sleeker portable devices like ultrabooks is driving the development of wireless docking technologies, which will replace bulky I/O connectors (like USB and HDMI) with multiple compact antennas. For all these reasons, Wi-Fi desperately needs additional bandwidth and speed – an express lane, so to speak.

One technology that addresses Wi-Fi's shortcomings is being developed by the Wireless Gigabit Alliance (WiGig), an organization formed in May 2009 to promote the adoption of multi-gigabit speed wireless technology and to advocate for a 60 GHz extension of the IEEE 802.11 standard, known as IEEE 802.11ad. WiGig uses 7 GHz of contiguous spectrum (67 to 64 GHz), divided into 2 GHz wide channels, enables WiGig to offer multi-gigabit data rates. Depending on the modulation and coding scheme implemented, the theoretical data rate can reach as high as 7 GBits/s. The 60 GHz band is also inherently resistant to interference, due to atmospheric absorption. This absorption also limits range; however, WiGig takes advantage of the frequency band's smaller antenna elements to implement phased array beamforming, extending the transmission range to 10 meters. (Download the alliance's white paper on WiGig technology for more information.)

The WiGig specification ensures seamless tri-band operation on the 2.4, 5, and 60 GHz bands. The traditional 2.4 and 5 GHz Wi-Fi physical layer will still be the gateway to broadband Internet access, since downstream Internet speeds are within 802.11n capabilities, while WiGig technology will enable wireless docking at 60 GHz, connecting wireless devices HD monitors, keyboards, mice, and speakers. WiGig's multi-gigabit data rates will also allow for wireless computing, display of HD video, sync of portable devices through IP based peer-to-peer applications, and sharing of network peripherals. WiGig-enabled A/V devices like HDTVs, digital set-top boxes, gaming systems, and Blu-ray players will likely follow at a later date.

The WiGig Alliance has already reached several key milestones in its quest to commercialize its technology, laying the foundation for continued progress toward that goal:

• Standard: From the beginning, the WiGig Alliance has been focused on defining a standard to ensure interoperability of WiGig devices. This includes the recent additions of new protocol adaptation layers (PALs) to define USB and PCIe I/O interfaces and an HDMI A/V interface.
• Partnerships: The WiGig Alliance has a partnership with the Wi-Fi Alliance to ensure seamless operation with existing Wi-Fi, as well as a cooperative agreement with the Video Electronics Standard Association (VESA) to develop interoperable wireless display products and provide an effective wireless alternative to cables, docking stations, and adapters.
• Regulatory Approval: WiGig has received ITU endorsement and IEEE 802.11ad draft status, and the WiGig Alliance expects that the IEEE standard will gain final approval in December 2012. "Expanding IEEE standard 802.11 to include WiGig will lend legitimacy to the technology," Brian O'Rourke, principal analyst at In-Stat, told me during a recent conversation.
• Device Development: WiGig members have developed tri-band chipsets and held a technology plugfest at MET laboratories in Santa Clara, CA, to validate the interoperability of various current designs, with a focus on the physical (PHY) layers. At the 2012 Consumer Electronics Show (CES) in Las Vegas, WiGig Alliance members demonstrated TVs, laptops, keyboards, mice, and wireless hard drives that meet the 802.11ad draft specification.
• Testing: Agilent Technologies introduced the first IEEE 802.11ad, WiGig-compliant test solution, providing a platform for design verification. "The 2 GHz modulation bandwidth of the WiGig signal in the 60 GHz band presented the biggest challenge, requiring new probing techniques, instrumentation, and software," David Grieve, Agilent's 60 GHz program lead and chair of the WiGig Alliance's Interoperability Working Group, explained.

What's next for WiGig? The alliance is now focused on defining the testing of higher layer protocols for a second plugfest in 2012, which will focus on medium access control (MAC) layers and protocol adaptation layers (PALs). Alliance members continue to fine tune the physical layers for production devices and some are working on advanced antenna techniques. It is possible that a few WiGig-enabled devices will emerge on the market this year; however, I believe wider support and acceptance of the technology won't happen until 2013. This means that companies with 60 GHz expertise still have time to apply for membership to the alliance and develop WiGig technology of their own. As Carlos Cordeiro, chief standards architect at Intel, chair of the 60 GHz Technical Task Group at the Wi-Fi Alliance, and technical editor at the WiGig Alliance, put it during a recent discussion: "Anyone is welcome to join the party."