0 years after its introduction, only a few smartphone models support CA_4_12 with band 12 as Pcell. Moving on to 2UL-xDL, the UE now has to face additional sources of self-interference from IMD products due to the simultaneous uplink operation. IMDs may impact the UE's own Pcell as well as several Scells, as explained in the next section. 12.5.2 EN-DC: Explosion of LTE-CA Combinations as Baseline to 5G With LTE-CA commercial deployments being the baseline of further 5G EN-DC com- binations, Figure 12.17 shows that 5G starts with an impressive number of 400+ distinct combinations. In comparison, it took LTE several years to reach 667 combinations. It is worth noting that FR2 plays an important role in the number of combinations, and the number of bands is likely to expand further. The pace at which new combinations are introduced is SO high that these numbers will probably be obsolete by the time of print- ing. This obviously further fuels complexity and challenges RF-FE solutions to deliver the best cost/number of supported combinations trade-off. 12.5.3 FR1 UE Types and Power Sharing in EN-DC There are two types of UEs in respect of uplink power sharing between LTE and 5G, namely, (1) UEs that support DPS between LTE and 5G and (2) UEs that do not support DPS. The UE informs the network which category it belongs to with the UE capability parameter dynamicPowerSharing. Support for DPS will become mandatory after initial deployments. UEs that do not support DPS cannot coordinate LTE and 5G transmission powers, and both modems independently set their own transmission powers without knowl- edge of other RAT transmissions. Therefore, these UEs rely on the network to guarantee by scheduling that P_LTE + P_NR < Pcmax, in other words, that the combined output power of LTE and 5G does not exceed the UE's output power capabilities. In an event that P_LTE + P_NR may exceed Pcmax, the network needs to configure the UE to use tdm-Pattern for single UL-transmission in which case only either LTE or 5G carrier is transmitted in