Flexibility in 5G NR Air Interface | Webinar 

Hi Rohit! Thanks for your question! In LTE we have 7 Frame configurations of UL-DL slots in TDD. In 5G, there are 56 different slot configurations which are defined, but that is applicable for FLEXIBLE slots in the 5G-FRAME. What about the other slots in a frame? How are they defined? For ex. with SCS as 15khz, we have 10 slots of 1ms each in Frame of 10ms. How are these defined? Are there any specific Frame configuration as we had in LTE? TD- LTE supports 7 TDD UL_DL Configurations. Each of these configurations indicate the number of subframes configured for downlink and uplink in a frame of 10 subframes. Service providers shall plan one of the 7 TDD UL_DL configurations during network planning and this configuration does not change over a period. 5G NR supports TDD UL_DL configuration at the granularity of OFDM symbols. Within a slot of 14 OFDM symbols, certain OFDM symbols can be configured for downlink and certain OFDM symbols for uplink and rest of the OFDM symbols are marked as flexible. OFDM symbols with Flexible configuration can be configured either as downlink or uplink or for switching time from downlink to uplink for a device. 5G NR supports 56 slot formats for TDD operation. Each slot format indicates number of symbols for downlink, for uplink and for flexible configuration in a slot of 14 OFDM symbols. The number of slots in a frame of 10 ms depends on subcarrier spacing. For example, grid with SCS 15 KHz offers 10 slots, SCS 30 KHz offers 20 slots and SCS 60 KHz offers 40 slots. Each of these slots is configured according to one of the 56 slot formats. Example of TDD configuration in 5G is depicted below: tdd-UL-DL-ConfigurationCommon referenceSubcarrierSpacing kHz30 pattern1 dl-UL-TransmissionPeriodicity ms5 nrofDownlinkSlots 7 nrofDownlinkSymbols 6 nrofUplinkSlots 2 nrofUplinkSymbols 4 In the above TDD configuration, with SCS of 30khz, a total of 10 slots are available in 5ms periodicity. Among 10 slots, first 7 slots are configured as downlink, last 2 slots are configured as uplink. In remaining one slot, first 6 symbols are configured as downlink, last 4 symbols are configured as uplink. Remaining 4 symbols are configured as Flexible. Flexible symbols can be configured either as downlink or uplink or for switching time from DL to UL, conveyed via dedicated RRC signaling to the device. Hope this answers your query. If you have any additional questions please reach out to me directly at Prakash@awardsolutions.com. Thanks again!