在5G中，TDD的配置非常灵活，可by cell-specific and UE-specific RRC消息。
并且帧格式可以通过PDCCH的DCI format 2_0动态告诉UE。
LTE 和 NR的不同
- 在LTE中，TDD的帧结构是预先定义了7中模式。
- 在5G/NR中没有预先定义任何模式，而是通过一些参数来配置具体的帧结构。（实则是配置的选项更多了，可以通过参数配置来预先设定更多的配置结构）
These parameters are defined in 38.331 as follows :
TDD-UL-DL-ConfigCommon ::= SEQUENCE {
referenceSubcarrierSpacing SubcarrierSpacing
dl-UL-TransmissionPeriodicity ENUMERATED {ms0p5, ms0p625, ms1, ms1p25, ms2, ms2p5, ms5, ms10} OPTIONAL,
nrofDownlinkSlots INTEGER (0..maxNrofSlots) OPTIONAL,
nrofDownlinkSymbols INTEGER (0..maxNrofSymbols-1) OPTIONAL,
nrofUplinkSlots INTEGER (0..maxNrofSlots) OPTIONAL,
nrofUplinkSymbols INTEGER (0..maxNrofSymbols-1) OPTIONAL
}
dl-UL-TransmissionPeriodicity : Periodicity of the DL-UL pattern
nrofDownlinkSlots : Number of consecutive full DL slots at the beginning of each DL-UL pattern
nrofDownlinkSymbols : Number of consecutive DL symbols in the beginning of the slot following the last full DL slot
nrofUplinkSlots : Number of consecutive full UL slots at the end of each DL-UL pattern
nrofUplinkSymbols : Number of consecutive UL symbols in the end of the slot preceding the first full UL slot
REf
38.331
38.211 section FFS