White Spaces: Avnera's ISM Analogy

This blog post references my cover story ‘White Spaces: Ready For Development Permits Or Off-Limits?‘ in EDN’s August 7, 2008 edition.

Avnera’s wireless audio transmitter-and-receiver chipset combos don’t operate in the VHF and UHF bands that White Spaces promoters hope to someday soon inhabit, but the 2.4 GHz ISM band is a no less challenging slice of spectrum real estate. As I wrote in my recent cover story:

The FCC’s (Federal Communications Commission’s) decision to open up the [ISM] bands for use by low-power transmitters and receivers in a license-free manner has resulted in an unparalleled explosion of adoption, both in the consumer-electronics realm and elsewhere.

But as I also forecasted way back in 2002, when 802.11b was still the ‘new kid on the block’:

As more consumers who fill their homes with cordless phones, garage-door openers, Wi-Fi networks, microwave ovens, and Bluetooth-based gear are discovering, regulation-free environments are also ripe settings for overuse and subsequent destructive interference.

Avnera and its competitors have a particularly challenging problem to solve. The human auditory system is fine-tuned to discern even fleeting glitches, but in combination with the visual system, it is also highly sensitive to ‘lip sync’ issues involving a delay between video and the corresponding audio track…or, for that matter, the delay between the different channels of a surround sound presentation. So how does wireless audio surmount interference-induced bitstream interruptions caused by transient spectrum inhabitors, without simultaneously introducing excessive buffer-induced latency, and without being a ‘spectrum bad neighbor’ itself?

I thought, in answering these questions, that Avnera would provide not only some insight into how White Spaces advocates will tackle similar situations but would also be an interesting interviewee in its own right. And company Chairman, CEO and President Manpreet Khaira didn’t disappoint me. Clearly still in possession of some formidable engineering skills, he told me about the tradeoffs that the company made in developing its technology, along with the additional Avnera-supplied ‘knobs’ that the company’s customers can ‘turn’ in doing further optimization work for their specific design goals (one versus two antennas, dynamic versus always-full-on transmission power, etc).

Khaira also provided background information on the strengths and shortcomings I experienced in the past while reviewing two Avnera-based products, the Rocketfish wireless speaker set and Acoustic Research’s wireless headphones. He also positioned Avnera against both 2.4 and 5 GHz ISM competitors such as Amphony and SST, and against emerging UWB alternatives. Finally, he shared detailed thoughts on both the difficulties and benefits of doing blended analog-plus-digital single-die IC designs.

Originally, I’d planned on just providing you with an abridged text summary of my nearly hour-long interview with Khaira. However, in re-listening to it while commuting during my long day last Thursday, I instead decided there was so much good stuff in it that I’d just provide you with the teleconference recording. Admittedly, I chopped off the front-end introductions and back-end goodbyes, along with slimming the MP3 bitrate to reduce the server storage and download payload. And remember, my original intent wasn’t to provide the audio of the discussion, so please excuse my less-than-completely polished interviewer banter. Nonetheless, I think it’s well worth 54 minutes of your time and 9.3 MBytes of your storage space, and I hope you agree. See below for the link; feedback is as always appreciated!

EDN’s interview with Avnera’s Manpreet Khaira (32 Kbps MP3)