Coopers Law and Shannon’s Theorum – Revisited

I had the opportunity to meet with Bill Bard of the University of Texas engineering department last week. Bill teaches a software defined radio course among other topics. During our discussion he posed the question – will we see more or fewer wireless standards in the coming years.

I made the prediction that we would continue to see new wireless standards emerge but that they would become less over time. The reason is that just as the web created the “long-tail” effect (the rise of many niches over the few hits) so software-defined radio would also create a “long-tail” effect but for wireless.

I’ve blogged before on Coopers Law which states that every 30 months the amount of information that can be transmitted over a given amount of radio spectrum doubles. This has held true since Marconi discovered the wireless signal in the late 1800s.

This is not to be confused with Shannon’s theorem which states in a mathematical formula the maximum information that can be transmitted over a communication channel.

While Shannon’s theorem refers to bits per hertz which has an upper limit, Coopers law takes into account frequency usage, spectrum allocation, and other variables related to wireless communication.

For those who don’t know the “long-tail” concept it was coined by Chris Anderson of Wired magazine who noticed that the web enabled niche players and gave them equal prominence as hit players. This applied to books, movies, etc. The internet distribution treated all equally unlike mass media (TV broadcasting for example) which favored hits over niche players.

Software defined radio levels the wireless field just as the internet leveled the media field. One no longer needs huge critical mass to create a standard and then adoption. Instead, software defined radio lets the user create their own wireless use case and with the power of standard PCs behind it, they can develop their own wireless protocols.

Changing the spectrum allocations is quite daunting given the government bureaucracy. But with some spectrum being used less than 0.3% of the time, pressure will mount to make use of that spectrum in some fashion. Software defined radio will provide a technical solution.

Best regards,
Hall T.