In my experience the big hurdle is getting your device certified, not licensing issues. That's not really an IP issue however, it's just that uncertified devices might misbehave and create issues for other users.

Mobile Telecoms standards are written by 3GPP, all BTSs and handsets (and for that matter, interfaces like 'A') are standard, and controlled by 3GPP. I believe they are open.

Not they belong to the companies and some of them are available under FRAND licensing.

For the rest there is the 3GPP patent platform.

I'd say it's patent law, not copyright law, that make the licences possible to enforce.

Most of the patents are the result of a lot of research and cleverness. Some of the patents are the equivalent of looking in another drawer if the first one did not contain what you are looking in.

It's a bit arbitrary that an API isn't protected when some bullshit patents are. There is clearly much thought in some of the java APIs.

I'd like to see shorter protection time for patents thought, especially in areas where there are very low investment costs, like software development.