5G NR TDD Slot Configuration
This is just to brush up on the main parameters defining the TDD slot format, configuration and pattern in 5G NR. As usual, to keep it simple, only the very basic scenarios are described and most common examples are presented below.
According to 3GPP TS 38.213 (11.1 Slot configuration), If a UE is provided tdd-UL-DL-ConfigurationCommon, the UE sets the slot format per slot over a number of slots as indicated by tdd-UL-DL-ConfigurationCommon.
The tdd-UL-DL-ConfigurationCommon provides:
The pattern1 provides:
If tdd-UL-DL-ConfigurationCommon provides both pattern1 and pattern2, the UE sets the slot format per slot over a first number of slots as indicated by pattern1 and the UE sets the slot format per slot over a second number of slots as indicated by pattern2.
The pattern2 provides:
The applicable values of P2 are same as the applicable values for P.
Below three examples of tdd-UL-DL-ConfigurationCommon and their graphical interpretation are presented:
The UE sets the slot format per slot over a number of slots as indicated by tdd-UL-DL-ConfigurationCommon.
A value P=0.625msec is valid only for SCS=120kHz. ?A value P=1.25msec is valid only for SCS=60kHz or SCS=120kHz. ?A value P=2.5msec is valid only for SCS=30kHz, or SCS=60kHz, or SCS=120kHz.
The applicable values of P2 are the same as the applicable values for P. A UE expects that P+P2 divides into 20 msec, e.g. P+P2 periods of 3+2 are permitted but periods of 1+2 ms are not permitted.
Within each pattern period, nrofDownlinkSlots?defines the number of downlink slots at the start of the period, while nrofUpnlinkSlots?defines the number of uplink slots at the end of the period.
The nrofDownlinkSymbols?defines the number of downlink symbols within the slot which follows the downlink slots.Similarly, the nrofUplinkSymbols?defines the number of uplink symbols within the slot which precedes the uplink slots.
Symbols and slots which remain unallocated at the centre of the pattern are treated as "Flexible" and can be subsequently allocated to either the uplink or downlink, but since we agreed to keep it simple, in the very basic scenarios and most common scenarios those unallocated symbols are "fixed" and serve as a guard period between DL and UL.
Mid-band 30kHz SCS TDD pattern with both Pattern1 and Pattern2 and one special slot
tdd_UL_DL_ConfigurationCommon
referenceSubcarrierSpacing = kHz30
pattern1
dl_UL_TransmissionPeriodicity = ms0p5
nrofDownlinkSlots = 3
nrofDownlinkSymbols = 3
nrofUplinkSlots = 2
nrofUplinkSymbols = 3
dl_UL_TransmissionPeriodicity_v1530 = ms3
pattern2
dl_UL_TransmissionPeriodicity = ms2
nrofDownlinkSlots = 4
nrofDownlinkSymbols = 0
nrofUplinkSlots = 0
nrofUplinkSymbols = 0
Right-click and Open image in new tab to enlarge:
Mid-band 30kHz SCS TDD pattern with both Pattern1 and Pattern2 and two special slots
tdd_UL_DL_ConfigurationCommon
referenceSubcarrierSpacing = kHz30
pattern1
dl_UL_TransmissionPeriodicity = ms0p5
nrofDownlinkSlots = 2
nrofDownlinkSymbols = 6
nrofUplinkSlots = 2
nrofUplinkSymbols = 4
dl_UL_TransmissionPeriodicity_v1530 = ms3
pattern2
dl_UL_TransmissionPeriodicity = ms2
nrofDownlinkSlots = 4
nrofDownlinkSymbols = 0
nrofUplinkSlots = 0
nrofUplinkSymbols = 0
Right-click and Open image in new tab to enlarge:
Hi-band (mmWave) 120kHz SCS TDD pattern with Pattern1 only and one special slot
tdd-UL-DL-ConfigurationCommon
????????????????? referenceSubcarrierSpacing kHz120,
????????????????? pattern1
??????????????????? dl-UL-TransmissionPeriodicity ms0p625,
??????????????????? nrofDownlinkSlots 3,
??????????????????? nrofDownlinkSymbols 10,
??????? ????????????nrofUplinkSlots 1,
??????????????????? nrofUplinkSymbols 2
Right-click and Open image tn new tab to enlarge:
Senior Engineer in Tech Mahindra 5G-NR || VO-NR || NSA || LTE || LTE+ ||E2E-testing
6 个月Hi, why we are considering dl_UL_TransmissionPeriodicity_v1530 = ms3 in pattern1 instead of dl_UL_TransmissionPeriodicity = ms0p5
wireless network optimization supervisor
9 个月Thanks
Cloud-native Open RAN Professional
10 个月well explained!
Staff Engineer at Qualcomm
1 年Mid-band 30kHz SCS TDD pattern with both Pattern1 and Pattern2 and one special slot and Mid-band 30kHz SCS TDD pattern with both Pattern1 and Pattern2 and two special slots figures are reversed?
LTE & 5G-NR Radio Engineer, Eden-Net SON, PMP
1 年Thanks a lot Andrew !