5G NR Frame structure | 5G Frame as per NR standard

This page describes 5G NR Frame structure. It describes 5G frame as per NR (New Radio) 3GPP standard. The 5G NR frame structure depicts subframes,slot and symbol configurations.

5G NR Supports two frequency ranges FR1 (Sub 6GHz) and FR2 (millimeter wave range, 24.25 to 52.6 GHz). NR uses flexible subcarrier spacing derived from basic 15 KHz subcarrier spacing used in LTE.

5G NR frame Structure

5G NR Frame structure 5G NR slots per subframe

A frame has duration of 10 ms which consists of 10 subframes having 1ms duration each similar to LTE technology. Each subfame can have 2μ slots. Each slot typically consists of 14 OFDM symbols. The radio frame of 10 ms are transmitted continuously as per TDD topology one after the other. Subframe is of fixed duration (i.e. 1ms) where as slot length varies based on subcarrier spacing and number of slots per subframe. As shown below, it is 1 ms for 15 KHz, 500 µs for 30 KHz and so on. Subcarrier spacing of 15 KHz occupy 1 slot per subframe, subcarrier spacing of 30 KHz occupy 2 slots per subframe and so on. Each slot occupies either 14 OFDM symbols or 12 OFDM symbols based on normal CP and extended CP respectively.

5G NR uplink downlink timing relation

Each 5G NR frame is divided into two equal size half frames with 5 subframes in each. Half frame-0 consists of subframes 0 to 4 and half frame-1 consists of subframes 5 to 9. Uplink frame-i start TTA time duration before the start of downlink frame-i.
➤TTA = (NTA + NTA, offset)*Tc
Physical layer timing unit, Tc = 1/(Δfmax*Nf)
Δfmax = 480 KHz , Nf = 4096
Tc = 0.509 ns

5G NR TA offset

NTA, offset is defined in TS 38.133 document as per table 7.1.2-2.

• OFDM symbols in a slot can be classified as 'downlink', 'flexible', or 'uplink'.
• Signaling of slot formats is mentioned in subclause 11.1 of TS 38.213 document. Table below mentions the same.
• In a slot in a downlink frame, the UE shall assume that downlink transmissions only occur in 'downlink' or 'flexible' symbols.
• In a slot in an uplink frame, the UE shall only transmit in 'uplink' or 'flexible' symbols.
• A UE not capable of full-duplex communication is not expected to transmit in the uplink earlier than NRx-Tx*Tc after the end of the last received downlink symbol in the same cell where NRx-Tx is given by TS 38.101 document.

Slot Formats in 5G NR Frame Structure (Normal CP)

As mentioned in the table, a slot can be all downlink, all uplink or mixed (i.e. combination of downlink and uplink). Here mixed refers to static, semi-static or dynamic. Slot aggregation is supported in 5G NR and hence data transmission can be scheduled to span one or multiple slots. Slot format indication informs UE whether an OFDM symbol is downlink, uplink or flexible. The figure below depicts the same.

5G NR Frame DL/UL combinations

Number of resource blocks per subframe is depicted in the following figure.

5G NR RBs per subframe

The figure depicts resource grid of 5G NR with symbols in time axis and subcarriers in frequency axis. 12 subcarriers form one PRB (Physical Resource Block). 5G NR supports 24 to 275 PRBs in a single slot. Occupied BW of 34.56 MHz (minimum) and 396 MHz (maximum) can be achieved for 120 KHz subcarrier spacing. One SS/PBCH Block occupies 4 OFDM Symbols in time domain and 24 PRBs in frequency domain. 5G NR SS consists of PSS and SSS as specified for LTE.
Also refer 5G mm wave frame structure>>.

5G NR Numerology | 5G NR Terminology

5G NR Control channels | 5G NR Traffic Channels | 5G NR Reference Signals and sequences

Frame structure of wireless standards, technologies

Frame structure of various wireless standards/technologies are mentioned below. It include WiMAX, WLAN, Zigbee, GSM, GPRS, UMTS, LTE, TD-SCDMA, GPS, SDH, 11ac WLAN, AMPS, Ethernet, VLAN etc.
WiMAX physical layer Frame Structure as per 802.16d and 802.16e standards
WiMAX MAC layer Frame Structure as per OFDM 802.16d standard
Zigbee RF4CE Frame Structure
Zigbee physical layer Frame Structure
Zigbee MAC layer Frame Structure
GPRS Frame Structure
GPS Frame Structure
LTE Frame Structure
TD-SCDMA Frame Structure
UMTS Frame Structure
SONET Frame Structure
SDH Frame Structure
802.11ac PHY Frame Structure
802.11ac MAC layer Frame Structure
WLAN Frame Structure as per 802.11a,11b,11n,11ac standards
AMPS Frame Structure
Ethernet Frame Structure
VLAN Frame Structure
GSM Frame Structure


This 5G tutorial also covers following sub topics on the 5G technology:
5G basic tutorial
5G Frequency Bands
5G millimeter wave tutorial
5G mm wave frame
5G millimeter wave channel sounding
Difference between 4G and 5G
5G testing and test equipments
5G network architecture
5G NR Physical layer
5G NR MAC layer
5G NR RLC layer
5G NR PDCP layer

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