To start, I'll echo the above. Research groups like Gartner do regular reports of the type you describe.
www.gartner.com of course they charge for these.
Other sites like Feirce Telecom,
www.fiercetelecom.com/ focus on the industry and provide general market news and feature stories related to the overall industry.
in addition you can use tools like Google Alerts to stay on top of stuff like this. I have Google Alerts for things like "VoIP market" to keep track of regular news in that industry.
There are other industry/market research firms that target on telecom as well. TNS Telecommunications Research has furnished some of the market reports I've used in the past, they're pretty good.
But all of these are really just best guesses when it comes to predicting the future. If they were really psychic, they'd be picking lotto numbers.