Nikkei Electronics Asia -- February 2007
Tech Feature
WirelessHD Group to Connect HDTV in Millimeter-Wave Band

Manufacturers in Japan, the US and Korea have banded together to develop wireless video transfer between audio-visual (AV) equipment in the home. The seven firms - Matsushita Electric Industrial Co Ltd, NEC Corp, Sony Corp, and Toshiba Corp, all of Japan; LG Electronics Inc and Samsung Electronics Co Ltd, both of Korea; and SiBEAM Inc of the US - have established a group, called WirelessHD, to draw up specs for wireless video transfer in the home using the 60GHz waveband (Table 1).

The 60GHz waveband is designated for unlicensed use in Japan, the US and Europe, with about 5GHz bandwidth free, which could mean an ultra-high speed communication interface running as fast as 5Gbps to 10Gbps. The group plans to issue the initial specification in spring 2007.

The prime target application is clearly transferring uncompressed high-definition television (HDTV) imagery. It is positioned as the wireless version of the High Definition Multimedia Interface (HDMI), which is spreading rapidly as a digital interface for displays. Industry people are hoping that it will interconnect HDTV recording equipment such as Blu-ray Disc and High-Definition Digital Video Disc (HD DVD) drives to large-screen TVs. Other applications being considered include connecting TVs to video cameras, digital cameras, high-grade audio gear and game systems (Fig 1). Transfer of compressed imagery is also a possibility, so that a single wireless communication scheme could handle just about everything.

For Higher Data Rates
The idea of using the millimeter waveband for wireless communication between AV equipment is not new. There are two key reasons why major household appliance manufacturers have become interested enough to form a promotion body.

The first is that wired interconnect schemes like HDMI are already being used to transfer uncompressed HDTV content between AV equipment in the home. Equipment manufacturers need to develop a new scheme for wireless transfer of HDTV imagery in preparation for the expected consumer demand for wireless implementation.

There are already other methods of wireless transfer for HDTV imagery in the home. IEEE802.11a/g, for example, can transfer about one channel of HDTV content. It requires data compression using Moving Picture Coding Experts Group (MPEG) or an equivalent, and cannot be used as a display interface. Ultra-Wide Band (UWB) is a possibility for transfer of uncompressed HDTV content, but the available wavebands are restricted due to possible interference issues, making it unlikely that it will ever accelerate to the 1Gbps level or above.

Transfer in the 60GHz range, however, could well replace HDMI. When it comes to picture-in-picture (PIP) TV applications, it can handle multiple channels in a multi-stream format. It would be possible to select from between multiple content streams at the display, for example - another advantage of high-speed communication.

The second reason is that there is increasing activity to implement the transceiver integrated circuits (IC) needed for millimeter-wave communication in relatively inexpensive complementary metal-oxide semiconductor (CMOS) technology, rather than conventional (and expensive) technologies like GaAs. If low-priced CMOS ICs become available, it is possible that the component cost of interface circuits could drop low enough for use in consumer equipment.

Looking to CMOS ICs
Of the companies driving WirelessHD, Silicon Valley venture start-up SiBEAM seems likely to become a CMOS IC manufacturer. (WirelessHD was established, in part, based on the high expectations the industry harbors for SiBEAM's CMOS ICs.)

SiBEAM has released very few details about ICs under development, but it is rumored that in addition to using CMOS technology it will also use smart antenna technology to support non-line of sight (NLOS) communications. The prototype is already completed and, according to a company spokesperson, "We should be able to offer a demo at the Consumer Electronics Show in 2007. Products using our chip will probably hit the market around the end of 2008."

Other Industry Bodies
WirelessHD has only just started. So far it has only described usage and announced that it will formulate standards for millimeter-wave communication.

The establishment of WirelessHD, however, is likely to stimulate other industry groups drawing up standards for the use of millimeter waves for high-speed communication in the home and office. A member of the IEEE802.15.3c group in the IEEE802 Committee, for example, commented, "The birth of WirelessHD will pressure us to accelerate work on 15.3c. If we take too long the whole purpose of the IEEE standard will be lost." A source at the WiMedia Alliance, a group applying (OFDM) technology in the 60GHz band, seems to be trying to slow WirelessHD down, commenting, "Millimeter wave technology is not yet mature." Discussion on closer interaction with other industry groups is likely to start soon.

by Hiroki Yomogita, Phil Keys

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