One of the big stumbling blocks remaining for widespread Bluetooth adoption continues to be interference issues in the 2.4 GHz unlicensed spectrum band, which the technology uses. In addition to household items using the spectrum band, numerous local area network standards also use the unlicensed band, including 802.11b, also known as Wi-Fi.
Bluetooth often is considered the troublemaker between the two technologies because of its fast frequency-hopping nature, up to 1600 hops per second, designed to prevent interference. If a Bluetooth transmission happens to hop onto a channel being occupied by Wi-Fi, which does not frequency hop, it can preserve its own transmission at the expense of Wi-Fi’s.
Portland, Ore.-based Mobilian Corp. says it has figured out a way to implement both technologies into a dual-chip solution that not only deals with the interference issues, but also allows both standards to operate at the same time with minimal interference. The solution, dubbed TrueRadio, is designed for use in PCMCIA cards in laptop computers allowing a continuos connection with little degradation of transmission.
“We have leveraged our understanding about where there is interference and developed technologies in the analog and digital signals to reduce degradation of signal,” said Frank Hanzlik, vice president of sales and marketing for Mobilian.
The key to TrueRadio is its Simultaneous Operation engine, allowing both technologies to operate at the same time. The Sim-Op engine includes an auto-detect mechanism designed to identify the correct network interface enabling a seamless end-user experience. Hanzlik noted Mobilian was able to develop TrueRadio because the company knew solutions operating in unlicensed spectrum bands, including the 2.4 GHz and 5 GHz bands, would need to be interference tolerant.
While TrueRadio does not eliminate all interference between Bluetooth and Wi-Fi, Hanzlik said it reduces it enough to make interference almost a non-issue.
“It’s not about a single operating standard,” Hanzlik said. “It’s about integrating more than one standard to work together cost-efficiently.”
The TrueRadio solution includes an analog chip providing the RF front ends for both the Bluetooth and Wi-Fi radios, in addition to the analog section of the Sim-Op engine managing interference between the two radio standards. The digital chip provides baseband processing for Bluetooth and Wi-Fi, and all of the modulation for the Sim-Op engine.
By combining the functions of the chips, Mobilian said it can reduce the external component count by more than 50 percent in comparison with discrete implementations of Bluetooth and Wi-Fi.
Samples of TrueRadio are expected to be available later this year, with production units in volume by the end of the year. Hanzlik said he expects PCMCIA cards for laptop computers using the solution to be available early next year for $100 to $150.
