 profile. This makes it ideal to offer different services, for example, for different business purposes or cus- tomers, within one 5G carrier. To support ultra-low latency for URLLC, 5G has specified support for the following techniques in Release 15: Short slot length via higher subcarrier spacing as shown in Figure 14.24: This reduces latency due to a shorter slot length, reduces the wait for the next slot, and provides Slot (1 1 ms) 15 kHz SCS 123456 Slot (0.5 ms) Slot (0.5 ms) 30 kHz SCS 12345678 01234567 Slot (0.25 ms) Slot (0.25 ms) Slot (0.25 ms) Slot (0.25 ms) 60 kHz SCS Slot (0.125 ms) x Slot (0.125 ms) x Slot (0.125 ms) x Slot (0.125 ms) x Slot (0.125 ms) x Slot (0.125 ms) x Slot (0.125 ms) x Slot (0.125 ms) 120 kHz SCS Figure 14.24 5G slot length for different subcarrier spacings (SCSs). 14 Internet of Things Optimization a faster turnaround time. Note that 5G can support multiple slot lengths in the same carrier, enabling different service mixes to be supported simultaneously. Data transmission shorter than a slot (i.e. using 2, 4, or 7 symbols in the downlink, and any number of symbols in the uplink). This allows for a packet to be transmit- ted in a very short time, processed quickly at the receiver, and the acknowledgment transmitted back to the transmitter. Flexible slot structure in TDD (i.e. a slot containing symbols for both data and HARQ feedback) to reduce the turnaround time. Preemptive scheduling and multiplexing of URLLC data within ongoing eMBB trans- mission: gNodeB (i.e. 5G base station) can preempt (i.e. puncture) ongoing data trans- mission with URLLC transmission. Preconfigured grant uplink transmission: UEs are assigned a preconfigured grant for uplink transmission and do not have to transmit a scheduling request to the gNodeB. The periodicity of the configured resources can be 2 symbols, 7 symbols, 1 slot, up to 5120 slots. Short uplink control transmission format (i.e. one or two symbols) to minimize the time to transmit HARQ-ACK feedback. Short periodicity for a scheduling reques