Samsung is only "forced" by group agreement if their patents were included in the ETSI standards patent pool.
Apparently these patents were not included as part of the essential standards (and are not covered under FRAND terms), but were used to enhance WCDMA operation by many companies, including Infineon.
Apple said they thought they had paid the patent fees via Intel, however Intel didn't buy Infineon until this year. Therefore the fees for all the chips that Infineon built before Intel took over, have not been paid.
Apple has, I think, conceded that point and now the debate is only over what is a reasonable amount.
Samsung is asking for 2.4% of the chip price per patent. E.g. if the chip costs $20, and there's three patents, then about $1.50 per phone.
Apple wants the patents declared to be covered under FRAND, to get a lower rate than that. It seems likely to me that they will at least eventually get a lower rate.
TL;DR - Some of Samsung's patents are not covered under FRAND rules, but Apple would like them to be.
Great.
Please link some sources that clearly state that some of the patents are not covered under FRAND. After, please link to those patents which are not covered under FRAND terms.
Thanks