@Rick, I was trying to follow these technologies for a while, but there does not seem to have been much happening lately. The last I heard was that a database had been approved for specific locations to avoid using it - mostly stadiums and theaters. I also know that California was trying to allocate some decent new ISM spectrum space which could be used, but that seems to have gone quiet as well. Other than that, I am not sure what is happening.
@Rick, my interest at the time was mostly driven by military applications since I was working for Northrop-Grumman at the time. The JTRS (Joint Tactical Radio System) program has probably done more to drive development of the technology in the military space than anything else. There are also some university programs that are working on it, typically paired with MANET (Mobile ad-hoc networking) protocols.
I would love to see some consumer applications of this technology. It is somewhat ironic to see the cell carriers experimenting with it for backhaul, since I primarily think of it as a way to do an end-run around having to feed the cellular meter every time I check my email.
As more specturm become avialable for shared use the importance of cognitive radio and Software Defined Radios (SDR) become ever more urgent. These bands, which will be distributed across a wide range of specturm, will have unique characteristics and constraints which will vary around the world. Successful devices will need to operate in multiple bands, under various policy restrictions and be able to aggregate non-continguous bands to accomoate the high demand for capacity. And these devices may need to change to different bands with only a few minutes of notice.
This adaptability and agility is at the heart of the what cognitive radio and SDR is all about. Highly integrated SoC processors are available today which can accomplish layer 1,2 and 3 processing requried by SDR in a single chip. For example, the new TI device is ideal for this application, TCI6630K2L .... sorry for the blantant plug, but it is a sweet chip!
@pflynn: I know TI has been working on SDR and cognitive radio chips for years...but is this technology deplyed in any mainstream cellular nets? What are the hurdles besides what the blogger mentions here in regulaitons?
@rick: In short, yes. There are several deployments of our TCI66xx architecture in the market today for WCDMA and now LTE solutions which are able to handle multiple bands simultaneously. Vendors are just beginning to apply this technology to backhaul and unlicensed shared specturm solutions.
When I lived in Russia during 2002, there was a small town with 9 different cellular operators and 2 independent mobile internet providers (yes, in GSM, internet and voice services can come from different companies on same channel). I wasn't surprising that even back then, cellular service there was already cheaper that in US.