Wireless communication in the 60GHz frequency band promises to enable exciting applications ranging from downloads at video kiosks to connections between laptop and printers. While the standardization committee is preparing the launch of the new standard (probably in 2009), research groups worldwide are racking their brains on the challenges associated with the use of this millimeter-wave portion of the RF spectrum.
Within reach of consumers
With all the current hype on 60GHz, one might forget that 60GHz wireless communication has been around for awhile, more specifically in the James-Bond sphere of high-security communications and military satellite-to-satellite communications.
Traditionally, 60GHz radios rely on the extraordinary characteristics of the expensive gallium arsenide (GaAs) material. Today, the advances in silicon processing technology (CMOS) enable smaller transistors with higher switching speed, making them more realistic candidates for the analog circuits in 60GHz radios.
The advantage of an analog radio front-end in CMOS technology instead of GaAs is that it can be seamlessly integrated with the digital radio baseband on one chip, resulting in a smaller one-chip, 'cheap' 60GHz radio. A James Bond technology comes within reach of consumer electronics.
In the short term, early 60 GHz multichip are being based on high speed silicon-germanium (SiGe) circuits. However, it is expected that the second generation of these radios will rely solely on plain silicon CMOS processes with true one-chip solutions. The latter could appear on the market by 2010.
Why 60GHz?
In 2001, the Federal Communications Commission (FCC) allocated a substantial block of 7GHz in the 57-64GHz band for unlicensed use. This 'unlicensed' aspect is a great advantage since this means that operators do not need to spend significant time and money to obtain a license from its national authority. Furthermore, this unlicensed band is available throughout the world, meaning that a worldwide harmonization around 60GHz is possible.
Click here for Figure 1.
Figure 1: Worldwide spectrum allocation in the 60GHz band.
Of course, the main advantage of the wide bandwidth available at 60GHz is that it enables high data rate wireless communication with capabilities far beyond current wireless standards (all below 10GHz).
An apparent disadvantage of 60GHz communication—its high propagation attenuation—turns into an advantage for the short-range applications: immunity to interference, high security characteristics and frequency reuse.
A world of possibilities opens
Thinking of high data rate (up to 5Gbit/sec) short-distance (3 to 5m) wireless communication, one can easily name dozens of applications. So let's just limit ourselves to the application domains that are described by the IEEE standardization committee as user cases:
- Wireless high-definition multimedia interface (HDMI). Uncompressed video can be wirelessly transmitted from a DVD player to a flat screen.
- Fast up and download of high-definition movies. Users can download high-definition movies from a video kiosk onto their mobile device or at home can download a movie from their mobile device onto the computer.
- Wireless docking station. A laptop computer can be wirelessly connected to the network, the display, an external drive, the printer, a digital camera etc.
Click here for Figure 2.
Figure 1: One application field of 60GHz wireless communication is the fast up and download of high-definition movies.
