Millimeter Wave Broadband Wireless, 1 Gbps now and 20 Gigabits per second or More Soon

Bridgewave Communications, the leading supplier of gigabit wireless solutions, has been selling the SLE100 point-to-point bridge that delivers highly reliable, low latency, wire-speed 100 Mbps full-duplex, half-mile (800-meter) connectivity since July 15, 2008. Built around BridgeWave’s field-proven 60 GHz radios, the SLE100 enables enterprise network managers to seamlessly extend LANs and achieve carrier-class performance at an unprecedented price for millimeter wave bridges. The SLE100 wireless bridge is priced at less than $10,000 per link (100mbps, 0.5 mile range). The 60 Ghz wireless bridge with 1 gigabit speed is less than $20,000 per link (1 gps, 0.75-1.5 mile range). The 80Ghz wirless bridge is more expensive but has up 4-6 miles of range.

MIT Technology Review reports that Batelle earlier in 2008, field tested a prototype millimeter communication system. The team was able to send a 10.6-gigabit-per-second signal between antennas 800 meters apart. And more recently, the researchers demonstrated a 20-gigabit-per-second signal in the lab.

Whereas Wi-Fi and cellular networks operate on frequencies of 2.4 to 5.0 gigahertz, millimeter-wave technology exploits a region from about 60 to 100 gigahertz. Much of the millimeter region is unlicensed and open for use; it has only been neglected because of the difficulty and expense involved in generating a millimeter-wave signal, encoding information on it, and then decoding at the other end. Usually, data is encoded by first generating a low-frequency wave of around 10 gigahertz, then converting it into a higher-frequency signal. The drawback is that encoding data on a 10-gigahertz signal limits the data rate to about one gigabit per second.

The Battelle team was able to better this by more than a factor of 10 using off-the-shelf optical telecommunication components. The researchers modulated data on two low-frequency laser beams, then combined the two. When these two beams combine, they create a pattern of interference that acts as a 100-gigahertz signal. “It looks as though we have a laser beam that has a 100-gigahertz frequency,” Ridgway says.

Competing technology is free space optics. Free space optics is faster but has more problems with interference from weather at atmospheric early 2008, HP demonstrated a free-space optical connection provided a 240 Gbit/s optical connection that beamed information through the air between boards. HP plans to sell free space optic connection products in 2009.

“We want to expand our photonics business to include all communications in the range of 100 nanometers on a chip all the way up to 100 meters between systems,” the HP executive added. “In the near term we want to connect boards and blades with photonic interconnects. In the long-term we want to build on-chip photonic connections which we think will break the core-to-memory bottleneck.”

Free space optics performance results showed stable operation when increasing the FSO communication system data rate from 2.5 Gbps to 10 Gbps in Sept 2006.


A record transmission of 1.2 tbps was made with free space optics.

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