I'm aware that they're considered to be essential. The question is, why? Are there any viable alternatives? If not, why not? Were standards manipulated to specifically include patented technologies? Who established the standard, and to what extent were government bodies (FCC etc) involved in the ratification process?
You will need to read chapter one of the tanemmbaumb book on networks, there is a wholle section dedicated to Standard setting methods. And do some more research on top (but please, for the love of all that is holly, do not ask an AI assistant about it)
The TL;DR is:
a.) standards bodies (some govermental, some private, some mixed) covene to "define a standard", in this case the 3GPP (the 3GPP is completely private, but works hand in hand with the ITU-T and ITU-R, In the past, they worked closely with ETSI as well, but I do not know about that now)
b.) Companies invest a m37r1c 5h170n of money on R&D to get the best tech, and lobby agressively to get their tech/patents on the standard for 2 reasons:
1.) Easy revenue stream through FRAND licensing &
2.) If your tech is selected as part of the standard you have a leg-up on your competitors, as you understand that tech better than anyone.
c.) Of course, what you give up by having your patents into the standard is that you cna not charge "whatevur" for your patents, the patents have to be FRAND, and, although there are disagreements from time to time, FRAND is a very specific set of conditions, highly (but not completely) aligned with jurisprudence dictated in germany
d.) In the case of standards, there is no way around the essential patents. For if you do not use those standard patents, your implementation is non-standards compliant, and therefore, the equipment is not interoperable. Not a big deal if you are making a (smart) fridge, absolutely essential if you want to make a 5G cellphone that wants to talk to any RAN, or want to make a RAN that can talk with any 5G cellphone.
----- TL;DR over
The patent, in this case, seems to be a pattent that allows a handset to inform (via signaling) the RAND to explain their transmit/receive power situation when the handset is using more than one frequency band at the same time, which is a disctintive feature of 5G (this was non existent in 2G and 3G, a bolted on thing in 4G, but is integral to 5G).
IANAL, but IMHO, this patent royalties shall be paid by BOTH the handset makers (Apple, Samsung et al), AND the RAN makers (Nokia, Ericsson et al*), but not by the network operators.
Possibly Acer wants to double dip, or maybe the Operators are willfully selling/pushing no-name handsets that did not pay up, and acer considers easier to go after the telcos themselves than after some "fly by the seat of your pants" Zhenzen/Mumbai handset maker.
I find it hard to believe that Nokia or Ericsson is not paying up for an Essential patent, but some no name phone maker? would not surprise me in the slightest.
* Bigest makers of RAN worldwide are Huawei, and Ericsson trading blows for first place, Nokia in 3rd, ZTE in 4th and Samsung in 5th, then there are many more. But note that Huawei and ZTE are banned in the USoA, where this lawsuit is taking place.