Joel L. Dawson is an entrepreneur, former MIT professor, writer, international speaker, and expert on wireless communications. He is the author of three books:
- PrEnergy Fundamentals of Radio, Wiley (2025)
- A Guide to Feedback Theory, Cambridge University Press (2021)
- Feedback Linearization of RF Power Amplifiers (co-author Thomas Lee), Kluwer Academic Publishers (2004)
He received the NSF CAREER Award in 2008, and was selected for the Presidential Early Career Award for Scientists and Engineers (PECASE) in 2009, the highest honor bestowed by the United States government on outstanding scientists and engineers in the early stages of their independent careers. One of his previous startup companies, Eta Devices, Inc., was named a Technology Pioneer by the World Economic Forum in 2015.
Abstract:
Title: Pushing to Nature’s Limit: Energy in Wireless Links
Data traffic has been growing at a rate of 20-30%, compounding annually, for many years now, while the available spectrum has not. This has led to a rational response, which is to prioritize above all spectral efficiency. That is, how many bits per second can we achieve for every Hertz of available bandwidth? The Shannon Limit gave us a concrete target to hit, and for decades we have poured all of our effort into reaching this mighty goal. Complex modulation strategies, sophisticated error correction codes, multiple antenna techniques and more have been developed at breakneck speed and given us network performance of which we can be justly proud.
The only thing missing from this tidal wave of progress is a commensurate push for energy efficiency. For a long time this was because from a practical standpoint energy really wasn’t important. Electricity was so far down on the list of operating costs for running a cellular network, for example, that if we were wasteful of energy it really did not hurt anyone’s bottom line. The result was that while energy efficiency has been discussed, even trumpeted, for decades, the truth is that as a field our heart hasn’t been in it. We discuss energy efficiency often, but when push comes to shove we aggressively implement the latest high-throughput methods and ask our hardware engineers to minimize energy in the aftermath.
We have reached the point where this cannot continue. We can no longer afford to pay exponentially in output power for linear gain in throughput; we can no longer optimize our radio hardware for use cases that never occur in the field; we can no longer use «software defined radio» as a euphemism for trading energy cost for flexibility; we can no longer let logarithmic loss units blind us to the real energy costs of our design decisions. In this brief talk, we overview common mistakes that we make as architects of wireless links, and examine a better way forward.
