ls, sometimes referred to as "mini-slot." Combined with a shorter slot duration, the dura- tion of an NR packet can be much shorter than that of an LTE packet. For example, the duration of a 2-OFDM-symbol data packet in a 120 kHz subcarrier spacing is only 1/56th of the duration in LTE, where the length of a transmission (i.e. a TTI) is 14 OFDM 13.3 Low Latency, Flexible Timing, and Modem Control Flow Complexity Table 13.5 Maximum number of monitored PDCCH candidates. Maximum number of Subcarrier PDCCH candidates per spacing (kHz) Slot duration (ms) slot and per serving cell symbols of 15 kHz subcarrier spacing. With a short transmission time, a small packet can be transmitted with a much lower latency in NR than in LTE. To reduce the modem processing burden, the processing time requirement is generally defined starting from the end of a reception. 13.3.1.3 Multiple PDCCH Monitoring Occasions Per Slot In LTE, the PDCCH is transmitted during the first three OFDM symbols of a slot. To enable mini-slot transmission to take effect under low latency, NR allows the transmis- sion of the PDCCH over any of the OFDM symbols in a slot. In SO doing, the time to wait for a transmit instance can be greatly reduced. To avoid the modem implementation burden due to more frequent PDCCH monitor- ing occasions, NR specifies an upper limit on the number of blind decoding candidates to be monitored as well as the number of control channel elements in which the channel estimation is to be performed within a slot for various PDCCH monitoring cases. These requirements have similar levels as in LTE for the case of 15 kHz subcarrier spacing. For other subcarrier spacings, the capability of handling PDCCH within 1 ms is larger in NR than in LTE. See Table 13.5 for the maximum number of monitored PDCCH can- didates per slot and per serving cell. The tasks involved in handling PDCCH include channel estimation, noise estimation, detection/decoding, pruning of blind decoding results, DCI parsing, and SO on. The impact of mini-slot transmission