n, the eNB does not schedule the UE more than the minimum number of subframes necessary to transmit the traffic corresponding to the selected channel access prior- ity class or lower than the following: (1) The channel access priority class signaled in uplink grant based on the latest buffer status report and received uplink traffic from the UE if type 1 uplink channel access procedure is signaled to the UE. (2) The channel access priority class used by the eNB based on the downlink traffic, the latest BSR and received uplink traffic from the UE, if type 2 uplink channel access procedure is signaled to the UE [5]. Four channel access priority classes are defined as shown in Table 8.3, which can be used when performing uplink and downlink transmissions on unlicensed carriers. In LTE-based LAA, each channel access priority class, used by user traffic, is associated with the stan- dardized LTE QoS class identifiers (QCIs); i.e., channel access priorities 1,2,3,4 are associ- ated with QCI values 1,3,5,65,66,69,70),(2,7),(4,6,8,9), respectively [5]. A non- standardized QCI (operator defined QCI) should use a suitable channel access priority class associated with the standardized QCIs, which best matches the traffic class. If a downlink transmission on physical downlink shared channel (PDSCH) is intended for which channel access has been obtained using channel access priority class pe {1, 2, 3, 4}, the LTE system must ensure that the transmission duration does not exceed the minimum duration needed to transmit all available buffered traffic; and further the transmission duration does not exceed the maximum channel occupancy time (MCOT)8 8 as defined in Table 8.3 for each channel Maximum MCOT is the maximum continuous transmission time after channel sensing, while Wi-Fi may transmit for much shorter time duration. The maximum continuous transmission time in license-assisted access is limited to 8 or 10 ms regardless of frame size and data rate. 870 Chapter 8 Table 8.3: Channel access priority classes in the downlink/upl