Energy Savings from Cognitive Radio and Cooperative Systems?

I find my self reading the  VTC 2011 workshop program where there is a workshop on Cognitive radio and Cooperative strategies for POWER saving (C2POWER). The key question asked is if these techniques can make up for the additional power spent in signal processing to actually save energy. I think this a relevant problem – however, in my view this discussion  clearly misses the main power saving potential: by making more spectrum available we can use less signal processing and less power hungry PHY-layers. Mainstream design in PHY-layer development has since the early 3G spectrum auctions being going down the path of maximizing spectrum efficiency and hasn’t looked back since then.  It is clear that cranking out as many bps in a given small piece of spectrum by using high-order linear modulation is not the way to energy efficiency.  In addition to extensive high-speed signal processing, the efficiency of power amplifiers is low – in the order of 10% or less.  Cooperative schemes are not likely to require less linearity from PA:s.

A more radical approach is if we instead spend our processing capabilities on dynamic spectrum access to free more spectrum, we could sacrifice spectrum efficiency and revert to low-order constant envelope schemes  where power amplifiers are  very efficient.  Potential energy savings in this approachs should be an order of magnitude, not just a few dB:s.

Jens Zander

About Jens Zander

Professor Jens Zander is professor in Radio Communication Systems at the Royal Institute of Technology, Stockholm, Sweden. He has been among the few in Swedens Ny Teknik magazine's annual list of influential people in ICT that have been given the epithet “Mobile Guru”. He is one of the leading researchers in mobile communication and is the Scientific director of the industry/academia collaboration center Wireless@KTH. His research group focuses on three main areas – the efficient and scalable use of the radio frequency spectrum, economic aspects of mobile systems and application and energy efficiency in future wireless infrastructures.
This entry was posted in Green radio. Bookmark the permalink.