ve SUO figure for EN-DC operation. LTE system, but the new NR band is likely to operate with a 30 kHz SCS. The mixing numerology operation complicates the UE internal timing design. 13.4.2.4 Operating in the Legacy LTE Band The new C-band might not be available in some regions (e.g. where the C-band has already been occupied by other applications). One alternative is a soft refarming-like approach [5] which deploys an NR system in a legacy LTE band. For this LTE/NR coex- istence scenario, special handling is required to avoid any negative impact on the legacy UE in the field. For example, CRS is present in every subframe for the LTE system, SO the NR PDSCH needs to perform CRS rate matching accordingly. As for uplink transmis- sion, the UE will face new challenges for intra-band EN-DC scenarios (e.g. LTE B41 + 1 NR n41¹ or LTE B71+ NR n71¹2 due to transmissions of LTE and NR signals in the same band. Since the NR PUCCH may only occupy a partial subframe, the gain control mod- ule in the UE has to handle the non-equal Tx power scenario within a transmission subframe (i.e. some OFDM symbols require a higher Tx power than others). 13.4.3 Uplink Transmission Design for Minimizing Intermodulation Effect For certain EN-DC band combinations (LTE B313 NR n77), it is observed that the intermodulation problem can degrade the LTE receiving sensitivity [6]. SUO, introduced above (see Section 13.4.1 point a), is adopted to solve the issue. In SUO, a predefined TDM pattern alternating between LTE and NR uplink transmissions is configured by the network. Figure 13.10 show a SUO example. In this example, it can be seen that LTE uplink transmissions are aggregated to some subframes (#7, #8, #2, #3) while NR uplink transmissions are over other subframes. For UE implementation, a specific controller is used to coordinate the EN-DC uplink transmissions, which impacts both LTE and NR modems. As discussed in this section, NR uplink design deals with the challenges incurred by new 5G deployment scenarios, including uplink power sharing