Vendors to tackle interference with Bluetooth
- — 28 November, 2001 08:28
A chip set and software that are due to be unveiled here next month at the Bluetooth Developers Conference will aim to let Bluetooth wireless network products avoid interference from other devices that use the same radio spectrum.
Bandspeed Inc. will demonstrate a chip set that can sidestep radio waves generated by IEEE 802.11b wireless LANs, which use the same spectrum of radio frequencies utilized by Bluetooth devices. It can also prevent interference from other devices that use the same 2.4GHz spectrum, such as microwave ovens and cordless phones, according to the company. The chip set works in conjunction with a modified Bluetooth protocol stack from Open Interface North America Inc.
While 802.11b wireless technology is beginning to catch on for LANs in offices, homes and public areas such as airports and conference centers, Bluetooth also is gradually becoming available on some portable devices as a substitute for cables. Because both technologies use the same radio spectrum, there is a potential for interference that could slow down or interrupt the wireless links. In homes, both technologies also face some danger of interference from other devices.
The Bandspeed-Open Interface product would be integrated into a Bluetooth module in a client device, said Rick Beale, vice president of marketing at Bandspeed. It can detect what frequencies in the 2.4GHz spectrum are occupied at any given time and cause the Bluetooth device to use other, unoccupied frequencies. It does not require any cooperation from the 802.11b network. The technique the companies use, called Adaptive Frequency Hopping, is being considered as a possible standard by the Institute of Electrical and Electronics Engineers (IEEE) and the Bluetooth Special Interest Group, Beale said.
The combined chip set and protocol stack will become available in products in the second half of next year, and will not add significantly to the price of a Bluetooth device, Beale said.
At least one other company is developing a solution to the Bluetooth-wireless LAN conflict. Mobilian Corp. is developing a chip set that will combine 802.11b and Bluetooth networking in a two-chip component for client devices and LAN hubs, according to Mike Mastalir, director of corporate marketing at Mobilian. That chip set will use patent-pending software and hardware capabilities to prevent interference and let users take advantage of both technologies at the same time. It will not prevent interference from other devices that use the 2.4GHz band, Mastalir said.
Analysts and vendors have long been aware of the conflict between the two technologies, but there are disagreements over how serious it is.
"The interference is not really as great as it was initially thought," said Chris Kozup, a Meta Group Inc. analyst in Burlingame, California. For example, on a client device such as a notebook PC, vendors may be able to avoid it just by positioning the two network components on different parts of the device, Kozup said. The greater conflict seems to be between 802.11b and Bluetooth LAN hubs, Kozup said, but this is unlikely to be a common problem as Bluetooth probably will not be widely used for LANs, he added.
Widespread adoption of Bluetooth and 802.11b wireless LANs remain the biggest question mark on the importance of these technologies, analysts said.
"Is it all of a sudden going to make a market out of Bluetooth? No," Kozup said. The still-high cost of components and lack of a unified standard have slowed deployment of that technology, he said.
Bluetooth is not being rapidly adopted in corporations or homes, said Jason Smolek, an analyst at International Data Corp. in Framingham, Massachusetts. Meanwhile, wireless LANs are racing toward higher speed -- and a new radio spectrum around 5GHz -- with the emerging 802.11a standard. Many vendors may have 802.11a products out within a year.
"You'll probably have 5GHz wireless LANs before this even becomes a problem," Smolek said.
The Bluetooth Developers Conference will run Dec. 11-13 in San Francisco. More information is available at http://www.key3media.com/bluetooth/.