There can be at most one active BWP per cell, except when the serving cell is configured with SUL, in which case there can be at most one on each UL carrier. When an inactivity timer is configured for a serving cell, the expiry of the inactivity timer associated to that cell switches the active BWP to a default BWP configured by the network. Switching between configured BWPs happens by means of RRC signaling, DCI, inactivity timer or upon initiation of random access. In unpaired spectrum, DL and UL switch BWP simultaneously. In paired spectrum, DL and UL can switch BWP independently.In addition, initial access is supported in each of the uplink Overlapping transmissions on PUSCH are avoided through scheduling while overlapping transmissions on PUCCH are avoided through configuration (PUCCH can only be configured for only one of the 2 ULs of the cell). In case of Supplementary Uplink, the UE is configured with 2 UL carriers for one DL carrier of the same cell, and uplink transmissions on those two UL carriers are controlled by the network to avoid overlapping PUSCH/PUCCH transmissions in time.

At the same time, under bad channel conditions, for example, at the cell edge, a lower-frequency SUL carrier typically allows for significantly higher data rates compared to the non-SUL carrier, due to the assumed lower path loss at lower frequencies. Thus, under good channel conditions such as the device located relatively close to the cell site, the non-SUL carrier typically allows for substantially higher data rates compared to the SUL carrier. In SUL scenario, the non-SUL uplink carrier is typically significantly more wideband compared to the SUL carrier. As an example, a downlink/uplink carrier pair operating in the 3.5 GHz band could be complemented with a supplementary uplink carrier in the 800 MHz band. SUL implies that a conventional downlink/ uplink (DL/UL) carrier pair has an associated or supplementary uplink carrier with the SUL carrier typically operating in lower-frequency bands. NR supports a supplementary uplink (SUL) to specifically handle this scenario. There is co-existence only in the UL direction, typically within the UL part of a lower-frequency paired spectrum, with NR downlink transmission taking place in the spectrum dedicated to NR, typically at higher frequencies.LTE/NR co-existence in both DL and UL directions.Two co-existence scenarios were identified in 3GPP and guided the NR design: Since the lower frequency bands are already occupied by LTE primarily, so for enabling early NR deployment in lower-frequency spectra, LTE/NR spectrum co-existence is thought of as the way for an operator to deploy NR in the same spectrum as an already existing LTE deployment. In conjunction with a UL/DL carrier pair (FDD band) or a bidirectional carrier (TDD band), a UE may be configured with additional, Supplementary Uplink (SUL) which can improve UL coverage for high frequency scenarios. In 5G NR, a downlink carrier may be associated with two uplink carriers (the non-SUL carrier and the SUL carrier), where the Supplementary Uplink (SUL) carrier is typically located in lower frequency bands, thereby providing enhanced uplink coverage.Д®xample of Supplementary Uplink: With SUL, the UE is configured with 2 ULs for one DL of the same cell as depicted in figure below: Example of Supplementary UplinkД«elow are the Operating Bands defined by 3GPP for NR in Frequency Range 1 where the duplex mode is SUL: Operating Bands supporting SUL as duplex mode Supplementary Uplink (in detail)

Downlink vs uplink