I don't think the patent exhaustion applies here. My understanding is that Qualcomm's customers are not covered under the current law. Qualcomm and Samsung likewise signed an agreement not to go after their customers years back, but Samsung ended that agreement when Apple filed lawsuits against Samsung last year.
Well, if Samsung's patents are valid, why not? Apple successfully banned Samsung's products in Germany. I guess Samsung could *copy* Apple's legal strategy and file lawsuits in Dusseldorf, Germany and Eastern District of Texas for favorable outcome.
In the recent Apple v. Samsung case, a jury of our peers found that Samsung's patent assertion on 3G essential patents did not apply, citing Apple's agreement with Qualcomm.
I'd expect the same result, at least in the U.S. (especially with that precedent) over 4G patents.
Patent exhaustion has a long history, and basically precludes people from double dipping. If Qualcomm is paying Samsung, Samsung cannot collect more, no matter what shady antics they try to do with the contracts. Contract law does not supercede the fundamentals (patent exhaustion) of the law.