dary Figure 8.13 Frame structure type 3 and LBT mechanism in LAA 22]. Operation in Unlicensed and Shared Spectrum 873 basis, where Nr is maximum ED threshold defined by regulatory requirements in dBm when such requirements are defined; otherwise [4]: -72 log10(BW MHz/20 MHz) dBm, ED threshold max (PH + 10log10(BW MHz/20MHz) PTX) where PH is a reference power equal to 23 dBm, TA = 10 dB for transmission(s) includ- ing PDSCH or TA = 5 dB for transmissions including discovery reference signal trans- mission(s) and excluding PDSCH, PTX is the configured maximum transmit power for the carrier in dBm, and it is given by Tmax = dBm/MHz + 10 log10(BW), where BW is the channel bandwidth in MHz. In a nutshell, the energy detection threshold can be increased if the bandwidth increases and/or the transmit power decreases. The detected energy level needs to be below this threshold for a certain period of time with a slot duration Tslot us and defer time Tdefer Tf + Mp, where Tf = 16(us)mp is based on the channel access priority class and is, therefore, traffic-type dependent and has a duration of at least one slot. The defer time is required to specifically protect Wi-Fi ACK/NACK transmission between the access points and the clients. As a result, the channel needs to be idle for an initial CCA period of 34 us and a maximum wait time of 88 us before an LAA-capable eNB can start its transmission. If the channel is sensed to be clear, the transmitter can only transmit for a limited amount of time defined as the maximum channel occupancy time T'MCOT: If the channel is sensed to be occupied dur- ing that time or after a successful transmission, the enhanced CCA period is started by generating a random number that is within the contention window. Because there are different traffic types (VoIP, video, background traffic, etc.), different channel priority access classes have been defined with different CW sizes and T'MCOT (see Table 8.3). If the most recent downlink transmission burst showed 80% or more decoding errors, as reported