The human body is a fascinating, well-oiled machine forged and perfected by hundreds of millions of years of evolution. So, when two MIT researchers were looking for a highly efficient design for a spectrum analysis chip, they turned to one of the most efficient designs in nature — the human inner ear — with outstanding results that will bring us 'smart radios' and transmitters capable of adaptively maximizing bandwidth and data transmission rates across all fields of communication.

Nature as the engineer's best pal

Bioelectronics, the research field of MIT associate professor Rahul Sarpeshkar, tries to apply knowledge of how the human body works to the world of integrated circuitry. Sarpeshkar says engineers can learn a great deal by studying biological systems, particularly when it comes to achieving highly efficient designs that have to cope with noisy environments while requiring very little power, and has widely demonstrated his thesis with much of his previous work.

Now, by mimicking the mechanics of the human inner ear, his team has managed to produce the "RF [Radio Frequency] cochlea," a highly efficient signal processing chip that can analyze and manipulate an incredibly high range of frequencies — from TV and radio to cellular and wireless Internet networks — in a way that is faster than any human designed radio-frequency spectrum analyzer and approximately 100 times as power-efficient.

"The cochlea quickly gets the big picture of what's going on in the sound spectrum," said Sarpeshkar. "The more I started to look at the ear, the more I realized it's like a super radio with 3,500 parallel channels."

His work also provides an insight as to what is the algorithmic efficiency of the natural cochlea, which is far superior to what researchers have achieved so far with standard digital signal processing. "In the implementation described in our paper, the RF cochlea is at least 50 times faster than a commercial spectrum analyzer with an equivalent number of frequency-resolving channels," he told us, where this performance directly reflects the efficiency of its natural counterpart.

Building a smarter radio

What about possible applications? "The most immediate would be in cognitive radio, where a quick measurement of the spectrum allows you to adapt your communication strategy in a 'smart radio' or in a 'cognitive radio' to get better bandwidth, reception, or transmission," said Prof. Sarpeshkar.

"Such advanced radios of the future will be designed to intelligently utilize parts of the spectrum that are frequently available but wasted because they are dedicated to a particular use (e.g. some TV channels, cell phone spectrum at 3am at night, avoidance of frequencies that are currently prone to jamming and interference because of the current radio environment etc)."

Prof. Sarpeshkar declined to speculate on when the RF cochlea might first appear in a commercial product: however, if the technology were licensed and an endeavor were made to commercialize it, it could likely be achieved within a couple of years.

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