Public safety rethinks PANs
Personal area network, or PAN, technology has experienced tremendous growth in the commercial market thanks to the demand for Bluetooth headsets. But the growth has not translated to the public-safety market — which is clamoring for wireless headset technology — because of interference and security concerns.
Global Bluetooth headset sales almost tripled in 2005 to 33 million units, according to research firm Strategy Analytics. The firm’s analysts forecast total wholesale revenues of $2 billion in 2007, making Bluetooth headsets the world’s largest accessory market for mobile devices. But public-safety end users simply don’t trust Bluetooth, especially when they hear about hackers accessing Paris Hilton’s cell phone via its Bluetooth port.
“Users have heard a lot of things in the news about the security implications of Bluetooth,” said John Lair, vice president of marketing for FreeLinc, a maker of wireless accessories for the two-way radio market. “They also know this is 2.45 GHz technology that is susceptible to interference.”
Indeed, long before Bluetooth became a hit in the commercial market, entities such as the Department of Homeland Security’s SAFECOM program were sounding the alarm about the potential security and interference issues associated with the technology. Bluetooth uses spread-spectrum frequency hopping across 79 random frequencies within a specified range, at a rate of 1600 frequency changes per second, but it shares the 2.45 GHz band with non-Bluetooth devices, such as 802.11b handsets and microwave ovens.
“It is thus critical that public-safety users carefully evaluate the environment where Bluetooth might be used,” SAFECOM wrote in a wireless technology guidebook published in 2003. “Bluetooth is especially not recommended for mission-critical applications in a mobile environment because of the difficulty in isolating this technology from potential sources of interference.”
But Mike Foley, executive director of the Bluetooth Special Interest Group, said the security criticisms lobbed at Bluetooth are overblown. “Bluetooth can be and is used in mission-critical applications all the time,” he said. The Austin (Texas) Police Department, for example, uses Bluetooth wireless headsets to communicate among its force.
The California Institute for Telecommunications and Information Technology (Calit2) at UC Irvine is developing a wearable, wireless multimodal communication system that lets first responders in emergency evacuations maintain constant two-way communication with an operations center.
The GPS/Bluetooth-equipped apparatus consists of a backpack-transported computer, video camera, wearable keyboard and wireless mouse. An eyeglass-mounted visual display, in conjunction with a full-duplex audio microphone and earpiece, provides updated real-time situation awareness. A sensor detects and communicates levels of dangerous gases present in an environment, while an avionics-designed helmet incorporates a compass, accelerometer and thermometer to transmit images and data to the control center (see story on page 52).
Foley said Bluetooth technology actually was developed with security in mind, with built-in features such as a mode that allows a radio to be turned on and off, a process that lets users set alphanumeric and lengthy PIN codes to authorize pairing, and the requirement that the owner of the device must accept contact. Add those features to the encrypted security algorithms built into the Bluetooth specification and the result is a wireless link that never has been broken, he said.
Also overblown are the criticisms regarding interference, according to Foley. “Understandably, the 2.4 GHz spectrum is a crowded one so interference in this spectrum is a common problem,” he said. “But often Bluetooth technology gets the bad rap in this area when it is not the culprit.”
Bluetooth’s adaptive frequency hopping feature allows the signal to jump around the radio wave, staying out of the way of other radio waves being used and thus avoiding interference, he said.
But although Bluetooth technology may be entering the public-safety marketplace, on a limited basis, it’s clear first responder two-way radios currently don’t have the capability. Motorola, which ranks as the largest vendor in the Bluetooth headset business, currently is not aggressively marketing its Bluetooth lapel microphones to public-safety users. Just two Bluetooth products work with Motorola two-way radios, and these radios are targeted at the commercial market. Spokespeople for the vendor were not able to provide any guidance as to when — or whether — Motorola will be targeting public safety with Bluetooth-capable wireless speaker microphones.
FreeLinc knows first-hand the trepidation public-safety has about the use of Bluetooth with two-way radios. Originally, the wireless accessories maker shopped the idea of manufacturing on a private-label basis a Bluetooth-enabled wireless speaker microphone for portable radios. It was told by OEMs that a 2.4 GHz-based product wouldn’t provide enough security to justify its use in mission-critical applications. So the company decided to produce the speaker microphone itself using near-field magnetic communications technology.
Operating in the low-frequency industrial, scientific and medical band at 13.5 MHz, near-field magnetic communications creates a three-dimensional bubble that envelops the user in about 5 feet of personal space and is — by the laws of physics — inherently private and secure. The technology has been around since the 1950s and has been used extensively for changing traffic lights.
“If someone were to intercept the signal, they’d have to be sitting in the user’s lap,” Lair said.
To further enhance security, as well as performance, FreeLinc has engineered the device to create a pairing sequence between the speaker microphone and adapter to prevent interference from rogue signals. “If the adapter detects another radio device — even another FreeLinc device — it won’t make the connection unless it has recognized the matching secure ID,” Lair said.
Interestingly, Aura Communications, which holds the intellectual property rights to near-field magnetic communications, originally positioned the technology as a direct competitor to Bluetooth in the consumer market, but failed to gain traction with handset vendors that already had committed to Bluetooth. In addition, near-field magnetic communications have a major disadvantage in the consumer market — its 5-foot range that compares unfavorably with Bluetooth’s 30-foot range.
But that major difference doesn’t matter to public safety, Lair said. Five feet is enough room, and users get high-quality voice as a trade-off.
“I saw how the technology was being used by some transportation officers in subways and figured if they can hear it, I should be able to hear it in the court room,” said Chris Marsh, a deputy with the White County (Ill.) Sheriff’s Office.
Marsh recently replaced his wired earpiece with FreeLinc’s wireless speaker microphone. He needed the radio capabilities so his dispatch center could keep in contact with him without interrupting court proceedings. “I love the mobility of it and the fact that you can be in the vehicle and have that in your ear and not be constrained by a wire,” he said.
FreeLinc is now the exclusive licensee of near-field magnetic communications and plans to apply the technology to a slew of applications, including helmet systems, remote push-to-talk buttons and remote surveillance kits. It’s also partnering with some well-known, though unnamed at this point, manufacturers that will license the technology and even build modules for new applications, according to Lair.
“There is no great solution at this point for communicating with a mask on,” Lair said. “Every firefighter has expressed dismay with the current options. … We’re putting a lot of R&D effort into that.”
|Technology||Bluetooth||Near-field magnetic communications|
|Spectrum band||2.45 GHz||13.5 MHz|
|Data rates||10 Mb/s||204.8 kb/s|
|Distance||30 feet||5 feet|
|Current uses||Cell phones, laptops, personal gaming devices, PDAs, computer keyboards, automobiles, digital cameras, cell phone headsets, medical devices||Wireless headsets|