Section: 5.6.2 Channel Access Priority Classes
Content: The Channel Access Priority Classes (CAPC) of radio bearers and MAC CEs are either fixed or configurable for operation in FR1: - Fixed to the lowest priority for the padding BSR and recommended bit rate MAC CEs; - Fixed to the highest priority for SRB0, SRB1, SRB3 and other MAC CEs; - Configured by the gNB for SRB2 and DRB. When choosing the CAPC of a DRB, the gNB takes into account the 5QIs of all the QoS flows multiplexed in that DRB while considering fairness between different traffic types and transmissions. Table 5.6.2-1 below shows which CAPC should be used for which standardized 5QIs i.e. which CAPC to use for a given QoS flow. NOTE: A QoS flow corresponding to a non-standardized 5QI (i.e. operator specific 5QI) should use the CAPC of the standardized 5QI which best matches the QoS characteristics of the non-standardized 5QI. Table 5.6.2-1: Mapping between Channel Access Priority Classes and 5QI When performing Type 1 LBT for the transmission of an uplink TB (see TS 37.213[ Physical layer procedures for shared spectrum channel access ]  [37], clause 4.2.1.1) and when the CAPC is not indicated in the DCI, the UE shall select the CAPC as follows: - If only MAC CE(s) are included in the TB, the highest priority CAPC of those MAC CE(s) is used; or - If CCCH SDU(s) are included in the TB, the highest priority CAPC is used; or - If DCCH SDU(s) are included in the TB, the highest priority CAPC of the DCCH(s) is used; or - The lowest priority CAPC of the logical channel(s) with MAC SDU multiplexed in the TB is used otherwise.