5G NR RESOURCE GRID

5G NR Downlink Resource Grid & 3GPP Visualizer

Downlink Numerology & BWP aware μ = 0–4 SSB · CORESET/PDCCH · PDSCH · DMRS · CSI-RS

A configuration explorer for the NR downlink: pick a numerology, bandwidth part and a few channels, and the grid re-renders every resource element from the 3GPP mapping rules. Hover any RE to inspect it. Companion to the 4G LTE resource grid.

3GPP release & assumptions

Release: formulas and tables follow 3GPP Release 17 (TS 38.211, 38.213, 38.214, 38.331). Values are stable across Rel-15..18 for everything implemented here.

• SSB — synchronization signal block with PSS, SSS and PBCH in a half-frame burst pattern (TS 38.213 §4.1).
• CORESET / PDCCH — control resource set and physical downlink control channel mapped in CCEs from REG bundles (TS 38.211 §7.3).
• PDSCH — RB allocation within the BWP; data REs are rate-matched around SSB, CORESET/PDCCH, CSI-RS and DM-RS (TS 38.214 §5.1.4).
• CSI-RS — all 18 rows of Table 7.4.1.5.3-1; ZP-CSI-RS shown as reserved REs.
• Not modelled: PT-RS, PUCCH/PRACH, multi-BWP switching, DCI-driven dynamic grants, full frequencyDomainAllocation bitmaps (CSI-RS row 1 uses RB offset mod 3).

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Configuration

Live

Numerology & carrier

Numerology μSCS = 15·2^μ kHz (TS 38.211 §4.2)

μ=0 · 15 kHz μ=1 · 30 kHz μ=2 · 60 kHz μ=3 · 120 kHz μ=4 · 240 kHz

Cyclic prefix

Normal (14 sym/slot) Extended (12 sym/slot)

Carrier bandwidth (N_grid)resource blocks (TS 38.211 Table 4.4.2-1)

24 RB 48 RB 51 RB 106 RB 133 RB 273 RB

offsetToPointA / N_start,gridCRB of the lowest carrier RB (TS 38.211 §4.4.4.2)

CRB

Physical cell ID (0–1007)derives DMRS shifts (PSS/SSS)

Bandwidth part (BWP)

BWP start (RB, relative to carrier)

BWP size (RB)

Duplex & slot format

Duplex mode

FDD (all downlink) TDD (slot format)

TDD slot format (0–55)D/U/F per symbol (TS 38.213 Table 11.1.1-1)

SS/PBCH block (SSB)

SSB case / SCStime pattern (TS 38.213 §4.1)

Case A · 15 kHz Case B · 30 kHz Case C · 30 kHz Case D · 120 kHz Case E · 240 kHz

L_max (SSBs per burst)

4 (f ≤ 3 GHz) 8 (FR1 3–6 GHz) 64 (FR2)

SSB lowest RB (CRB of SSB RB 0)

k_SSB (ssb-SubcarrierOffset)

CORESET / PDCCH

Start symbol / duration1–3 symbols (TS 38.211 §7.3.2.2)

len 1 2 3

Frequency (RB, relative to BWP)

× RB

CCE-to-REG mapping

Non-interleaved Interleaved L 2 3 6

Highlight PDCCH candidateaggregation level × first CCE

none AL 1 AL 2 AL 4 AL 8 AL 16 @CCE

Slot periodicity / offsetmonitoring pattern (TS 38.213 §10)

period offset

PDSCH / DMRS

Mapping type / start / lengthSLIV (TS 38.214 §5.1.2.1)

Type A Type B S L

DMRS config type / add. positions

Type 1 (comb-2) Type 2 add pos0 pos1 pos2 pos3

RB allocation (within BWP)frequency resource assignment (TS 38.214 §5.1.2.2)

start × RB

Slot periodicity / offset

period offset

dmrs-TypeA-Position / CDM groups w/o data

pos2 pos3 CDM 1 2 3

CSI-RS

Row (Table 7.4.1.5.3-1)

Row 1 · 1p · density 3 Row 2 · 1p · density 1 Row 3 · 2p · FD-CDM2 Row 4 · 4p · FD-CDM2 Row 5 · 4p · FD-CDM2 Row 6 · 8p · FD-CDM2 Row 7 · 8p · CDM4 Row 8 · 8p · CDM4 Row 9 · 12p · noCDM Row 10 · 12p · CDM4 Row 11 · 16p · FD-CDM2 Row 12 · 16p · CDM4 Row 13 · 24p · noCDM Row 14 · 24p · CDM4 Row 15 · 24p · CDM8 Row 16 · 32p · FD-CDM2 Row 17 · 32p · CDM4 Row 18 · 32p · CDM8 ZP

First symbol l0 / subcarrier k0 (in RB)

l0 k0 dens off

Slot periodicity / offset

period offset

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Resource Grid

Downlink · Live

View span:

Slot Subframe Frame

Zoom: 100%

Hover over any resource element to inspect its channel, CRB/PRB, subcarrier, symbol & slot

Reference · 3GPP Release 17

My Future Networks / 5G NR Downlink Resource Grid

Release and assumptions Subcarrier spacing Downlink channels CCE to REG bundles Questions Related tools

3GPP Release & Technical Assumptions

This 5G NR downlink resource grid is a Release 17 visualizer for the physical resource grid in 3GPP TS 38.211, the procedures in 3GPP TS 38.213, and the PDSCH mapping rules in 3GPP TS 38.214. The placements used here are the ones that stayed stable from Release 15 through Release 18 for the channels this page draws. Pick a numerology, a bandwidth part, and the channels, and every resource element is placed from those mapping rules.

A resource element is one subcarrier in one OFDM symbol. A resource block is 12 consecutive subcarriers. Common resource blocks are numbered from Point A. Physical resource blocks are numbered from the start of the active bandwidth part.

Configurable parameters

• Numerology μ from 0 to 4, so subcarrier spacing is 15 × 2^μ kHz, plus normal or extended cyclic prefix.
• Carrier bandwidth in resource blocks, offsetToPointA, and physical cell ID from 0 to 1007.
• Bandwidth-part start and size, relative to the carrier.
• FDD, or TDD with a slot format from TS 38.213 Table 11.1.1-1.
• SSB case A to E, Lmax, the SSB common resource block, and kSSB.
• CORESET start symbol, duration of 1 to 3 symbols, frequency span, CCE-to-REG mapping, REG bundle size, and one PDCCH aggregation level.
• PDSCH allocation, DM-RS, and CSI-RS row, including every row of TS 38.211 Table 7.4.1.5.3-1 and ZP-CSI-RS.

This page does not draw PT-RS, PUCCH, PRACH, multi-BWP switching, or DCI-driven grants. Uplink and the cell-bring-up calculators are in Resource Grid Lab. The fixed 15 kHz picture is the 4G LTE Resource Grid Tool.

How subcarrier spacing changes the 5G resource grid

Numerology μ is the control that rescales the whole grid. Spacing is 15 × 2^μ kHz. Each step doubles the subcarrier spacing, halves the slot length, and doubles how many slots fit in 1 ms. The resource element stays one subcarrier by one symbol, so a fixed carrier bandwidth contains fewer resource blocks as μ grows, and each symbol gets shorter.

NR numerology μ = 0 to 4 (TS 38.211 clause 4.2, normal cyclic prefix unless noted)

μ	Subcarrier spacing	Slots per 1 ms	Slot duration	Symbols per slot
0	15 kHz	1	1 ms	14
1	30 kHz	2	0.5 ms	14
2	60 kHz	4	0.25 ms	14, or 12 with extended CP
3	120 kHz	8	0.125 ms	14
4	240 kHz	16	62.5 µs	14, SS/PBCH only

Extended cyclic prefix is defined only for μ = 2. μ = 4 is the SS/PBCH numerology, not a PDSCH numerology. Changing μ on this page rebuilds the grid, including which SSB case still lines up with the carrier spacing.

NR Downlink Channels on the Grid

Each cell of the canvas is one resource element. Hover a cell to read its channel, CRB, PRB, subcarrier, symbol, and slot. The notes below are the mapping that drawing uses.

SSB

The SS/PBCH block is 20 resource blocks by 4 OFDM symbols: PSS, then PBCH with its DM-RS, then SSS together with PBCH, then PBCH with its DM-RS again. Time positions follow case A at 15 kHz, case B or C at 30 kHz, case D at 120 kHz, or case E at 240 kHz. A half-frame burst holds Lmax of 4, 8, or 64 candidate SSBs (TS 38.213 clause 4.1). The CRB and kSSB controls place that block on the carrier.

CORESET

A control resource set is the time-frequency region where PDCCH may be sent. Duration is 1, 2, or 3 OFDM symbols. The frequency span is a multiple of 6 resource blocks inside the bandwidth part (TS 38.211 clause 7.3.2.2).

PDCCH

PDCCH carries downlink control information in control-channel elements. One CCE is six REGs, and a candidate uses aggregation level 1, 2, 4, 8, or 16. The highlight on this grid is one candidate at a chosen first CCE, on the monitoring occasions you set.

PDSCH

PDSCH resource element mapping fills the allocated resource blocks and symbols, then removes PDSCH DM-RS, the SSB, an overlapping CORESET, and CSI-RS. That rate matching follows TS 38.214 clause 5.1.4 for the channels this page models.

DM-RS

Demodulation reference signals sit inside the PDSCH allocation and inside each PDCCH REG so the receiver can estimate the channel. Position depends on the antenna port and the cell ID. PDSCH mapping skips them.

CSI-RS

CSI-RS is the channel-state reference used for beam management and CSI reporting. This grid draws all 18 rows of TS 38.211 Table 7.4.1.5.3-1. ZP-CSI-RS is shown as reserved resource elements, and PDSCH skips those too.

Mapping CCEs to REG bundles

One REG is one resource block on one OFDM symbol of the CORESET: 12 resource elements, some of them PDCCH DM-RS. One CCE is always six REGs. The REGs are grouped into REG bundles before a CCE is assembled.

• Non-interleaved mapping uses bundle size 6, so each CCE is one contiguous bundle.
• Interleaved mapping uses bundle size 2, 3, or 6. The size has to agree with the CORESET duration, and the bundles are then permuted across the CORESET (TS 38.211 clause 7.3.2.2).
• Aggregation level L means the PDCCH candidate occupies L CCEs. This page highlights L = 1, 2, 4, 8, or 16.

LTE uses a different unit. There a REG is four resource elements and a CCE is nine REGs. That map is on the 4G LTE Resource Grid Tool.

Questions engineers ask

How does subcarrier spacing (μ = 0 to 4) affect the 5G resource grid?

Numerology μ sets the subcarrier spacing to 15 × 2^μ kHz. μ = 0 is 15 kHz and one 1 ms slot per subframe. μ = 1 is 30 kHz and 0.5 ms, μ = 2 is 60 kHz and 0.25 ms, μ = 3 is 120 kHz and 0.125 ms, and μ = 4 is 240 kHz and 62.5 μs. A resource element is still one subcarrier in one OFDM symbol, and a resource block is still 12 subcarriers, but the same bandwidth holds fewer resource blocks as the spacing grows. Normal cyclic prefix has 14 symbols per slot. Extended cyclic prefix exists only for μ = 2 and has 12 symbols per slot. 3GPP uses μ = 4 for the SS/PBCH block, not for PDSCH.

What is the difference between a resource element, a PRB, and a CRB?

A resource element is one subcarrier in one OFDM symbol. A physical resource block (PRB) is 12 consecutive subcarriers inside the active bandwidth part, numbered from that BWP. A common resource block (CRB) is the same 12-subcarrier unit numbered from Point A across the carrier. offsetToPointA and the BWP start convert a CRB index into a PRB index (TS 38.211 clause 4.4). Hover any cell on this grid to read the channel, the CRB, and the PRB.

How are CCEs mapped to REG bundles?

In a CORESET, one resource-element group (REG) is one resource block on one OFDM symbol: 12 resource elements, including the PDCCH DM-RS positions. One control-channel element (CCE) is six REGs. Non-interleaved mapping uses a REG bundle size of 6. Interleaved mapping uses a bundle size of 2, 3, or 6 and spreads those bundles across the CORESET (TS 38.211 clause 7.3.2.2). A PDCCH candidate then takes an aggregation level of 1, 2, 4, 8, or 16 CCEs. The mapping, bundle size, and aggregation level controls on this page redraw that assignment.

Where does the SSB sit on the NR downlink resource grid?

An SSB occupies 20 resource blocks and 4 OFDM symbols: PSS, PBCH with DM-RS, SSS plus PBCH, then PBCH with DM-RS. Cases A through E select the subcarrier spacing and the symbol positions of the burst (TS 38.213 clause 4.1). Lmax is 4, 8, or 64 candidate SSBs in a half-frame. Set the SSB CRB and kSSB to move the block in frequency.

How does PDSCH resource element mapping avoid SSB, CORESET, and CSI-RS?

PDSCH data uses the resource elements inside the allocated blocks and symbols that are not already taken by PDSCH DM-RS, the SSB, a CORESET that overlaps the allocation, or CSI-RS. ZP-CSI-RS is reserved the same way. That is the rate matching in TS 38.214 clause 5.1.4 for the channels this visualizer draws. PT-RS is not modelled here.

How is this 5G NR resource grid different from the 4G LTE resource grid?

LTE uses a fixed 15 kHz subcarrier spacing, a control region sized by CFI, and PCFICH plus PHICH in front of PDCCH. NR replaces that fixed control region with a CORESET, adds numerology μ, bandwidth parts, and Point A, and draws the SSB burst, DM-RS, and CSI-RS on the same grid. The LTE map is the 4G LTE Resource Grid Tool. Uplink for both generations is in Resource Grid Lab.

Related resource-grid tools

• 4G LTE Resource Grid Tool — PSS, SSS, PBCH, cell RS, PCFICH, PHICH, PDCCH, and PDSCH at 15 kHz.
• Resource Grid Lab — 4G and 5G uplink grids, plus CellConfig, Point A, CORESET#0, MCS / TBS, and MIB-to-PDSCH.
• 3GPP TS 38.211, 3GPP TS 38.213, and 3GPP TS 38.214 — the specifications this grid is drawn from.
• My Future Networks — more 5G and LTE notes on this site.

You are in the free 5G NR downlink

This map is the trailer. The lab is the rest of the radio.

Change a setting above and watch SSB, CORESET, PDCCH, PDSCH, DM-RS, and CSI-RS land on the grid. Resource Grid Lab is the same kind of picture for uplink, for the other generation, and for the calculators that take a cell from a band number to the first PDSCH. The trial is 30 days, once per verified email.

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• Grids. 4G downlink, 4G uplink, 5G downlink (this page), 5G uplink
• PHY. CellConfig, raster and band, Point A, CORESET#0, allocation, MCS / TBS, TDD / HARQ
• Bring-up. MIB, PDCCH CCE, PCI, RNTI, PRACH, timing advance, MIB to first PDSCH

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