2011年7月30日星期六

Steve Perlman, DIDO, Wireless, Cellular DIDO promises wireless breakthroughs

SAN JOSE, Calif. – A serial entrepreneur released a white paper describing a wireless technology that can deliver more than ten-fold increases in spectrum utilization compared to today's cellular systems.

The Digital Input, Distributed Output (DIDO) method can radically extend the range while decreasing the power consumption and silicon complexity of radios, its inventors claim.

"We have only scratched the surface of the potential of this technology," said Steve Perlman, chief executive of Rearden Companies, a Palo Alto, Calif. incubator and one of the DIDO inventors.

"We believe there are not only far more applications in communications, but we believe that the unprecedented control and capacity that we have with radio signals will lead to a wide range of applications in other fields, such as medicine, imaging, manufacturing and alternative energy," he said in the white paper now posted online.

The technique uses a data center as an intermediary for all wireless communications. The servers apparently compute waveforms specific to each wireless client's data request.

Each client receives a unique waveform with justthat user's data. DIDO does this by synthesizing a private channel for eachuser, which is why each user gets 100 percent of the data rate of the spectrum,regardless of how many users share the spectrum, Perlman said.

Rearden has tested the technique with ten radios, each using the full data rate available for a given slice of spectrum in a site near Austin, Texas.

"We know we can get to one-hundred fold what today's cellular systems provide, and we are optimistic we can get to a thousand-fold," said Perlman in a recent talk at Columbia University where he first publically described DIDO. "We don’t know what the limit is [because] this is all green-field" research, he added.

The average power is easily one-tenth that of cellular, and in many cases its one one-hundredth, Perlman said

In a fully deployed DIDO system, the antennas are far closer to the user on average than in a cellular system where, for example, many users are on the fringes of the system, he explained. Also, DIDO doesn't transmit much power where there are no users, so this is far less wasted RF energy, he added.

In terms of silicon complexity a DIDO access point radio can be as simple as an A/D, D/A and an amplifier, said Perlman. All it is doing is digitizing and transmitting, or receiving and digitizing a digital waveform. It does no processing at all, he said.

A DIDO user radio has a little more to it because it is a portable radio, but it is closer to a walkie-talkie than a 3G radio in complexity, Perlman said.


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Steve Perlman, DIDO, Wireless, Cellular DIDO promises wireless breakthroughs