UWB in a Handheld
May 20, 2004
A chip shown by in China this week may be the precursor to a future of high-speed ultra-wideband wireless in roducts like digital camcorders and televisions -- perhaps even by next year.
On May 18th in Beijing, Haier Corporation and Freescale Semiconductor, a subsidiary of Motorola, demonstrated a wireless connection between a 40-inch plasma display and a handheld camcorder using direct sequence ultra-wideband (DS-UWB) technology. The demonstration took place at China's National Science and Technology Show, which runs May 15-22.
According to Martin Rofheart, Freescale's director of UWB Operations, the demonstration was particularly relevant in terms of proving the commercial viability of UWB technology for handheld applications.
"It's the first time that anyone has shown UWB in the class of applications where it really shines, in multimedia audio/video wireless connectivity for handheld devices," he says.
The demonstration involved the transmission of live data at 20 megabits per second from a digital camcorder, beaming video footage to a plasma television display. Freescale's current technology can go up to 114 megabits per second, and can transmit up to three simultaneous streams over a single UWB connection.
UWB's greatest strength, Rofheart says, lies in its speed/power ratio. "From a handheld perspective, what you care about is how many bits you can move for a given amount of battery that you consume," he says. "If you look at Bluetooth, 802.11a, 802.11b, and 802.11g, they all take about the same amount of energy to move the same amount of data. Ultra-wideband is literally ten times better at that metric."
In an application like the one demonstrated in Beijing, UWB can help camcorders and similar handhelds operate much more efficiently. "The battery will last ten times longer for moving the same pile of data, or move ten times as big a pile for the same battery life," Rofheart says. "From a handheld perspective, that's a big deal."The demonstration made use of Motorola's ultra-wideband XtremeSpectrum chipset.
"It's the first productized chipset out there," Rofheart says. "We've refined the software layers and the system layers that go with it, and we've got it into a form factor and functionality that delivers a level of performance that is unequaled."
UWB implementations today are split between two competing technologies: direct sequence ultra-wideband, supported by a the UWB Forum that includes Freescale and a number of smaller companies, and the MultiBand OFDM Alliance, supported by a consortium that includes Intel, Panasonic, Philips, and Sony, among many others.
The most significant difference between the two standards, Rofheart suggests, lies in power consumption. "Both multiband OFDM and direct sequence can deliver comparable performance," he says. "But when you start looking at handheld applications, direct sequence is far less complex, less power-consumptive, and less costly than the multiband OFDM solution."
For handheld products, that could prove a key differentiator for direct sequence ultra-wideband. "If you look at this form of connectivity--handheld audio/video devices, storage peripherals, and things of that type--many of them are battery-operated," Rofheart says. "What we need is a wireless technology that will enable that, and the direct sequence UWB is just a far simpler, more elegant solution."
Time to market
Direct sequence ultra-wideband, Rofheart says, also has a two-year head start on multiband OFDM. "There's no prototype, even, of a multiband OFDM system," he says. "That's why there are so many companies in the [multiband OFDM] group. There's no opportunity for them to figure out anything here--we've got that big a head start."
According to Rofheart, the technology that was demonstrated in China will be released to the consumer market by Christmas of 2004. By the end of 2005, Freespace expects to advance to the point where it can transmit a full gigabit per second, and hopes to have devices operating at that speed released by 2006.
"It's a pretty compelling solution," he says.