4G LTE Resource Grid

You are in the free 4G LTE downlink

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

Change a setting below and watch PSS, SSS, PBCH, cell RS, PDCCH, and PDSCH 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.

Access code

TRIAL

Sign in with Google, paste this code, then pick any tool.

Start the 30-day trial
  1. 1 Open the lab
  2. 2 Sign in with Google
  3. 3 Paste TRIAL
  • Grids. 4G downlink (this page), 4G uplink, 5G downlink, 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

Teaching a class, or want a licence after the trial? Open the lab and press Contact. We ask for your name, email, mobile, and a short message, then reply by email. The form does not show our address.

4G LTE Resource Grid

Downlink Interactive PRB map FDD & TDD PCFICH · PHICH · PDCCH · PDSCH

A hands-on view of how the LTE downlink maps synchronization, broadcast, reference, and control channels onto individual resource elements. Tweak the parameters and watch the grid rebuild in real time. Companion to the 5G NR resource grid.

3GPP release & assumptions

Release: channel mapping follows 3GPP Release 17 (TS 36.211, 36.213, 36.331). The formulas used here are stable across Rel-8 through Rel-18 for everything implemented.

  • PSS/SSS — primary and secondary synchronization signals in subframes 0 and 5 (TS 36.211 §6.11).
  • PBCH — physical broadcast channel carrying the MIB in subframe 0, centred around DC (TS 36.211 §6.6).
  • Cell RS — cell-specific reference signals for up to four antenna ports (TS 36.211 §6.10).
  • PCFICH / PHICH / PDCCH — control region sized by CFI; PHICH groups derived from Ng and duration (TS 36.211 §6.7–6.8).
  • PDSCH — data region in remaining OFDM symbols, rate-matched around control and reference REs.
  • Not modelled: EPDCCH, CSI-RS (Rel-10+), DMRS for PDSCH, multi-cell ICIC, carrier aggregation.

Wait a sec… loading the interactive grid…

Resource Grid

Downlink · Live
View span:
Zoom: 100%

Generated live from the configuration and 3GPP channel-mapping formulas. Each cell is a resource element (RE) colored by the channel it carries — hover to inspect.

Hover over any cell to inspect its channel, subframe, slot, symbol & subcarrier

About the 4G LTE downlink resource grid

The LTE downlink physical resource grid is a time–frequency lattice of resource elements (REs), grouped into physical resource blocks (PRBs) of 12 subcarriers × 1 slot. This tool draws the grid live from your configuration so you can see exactly which REs carry synchronization, broadcast, reference, and control signalling.

LTE downlink channels on the grid

PSS / SSS
Primary and secondary synchronization signals for cell search and frame timing (subframes 0 and 5).
PBCH
Physical broadcast channel carrying the Master Information Block (MIB) in the centre PRBs of subframe 0.
Cell RS
Cell-specific reference signals used for channel estimation, mapped per antenna port.
PCFICH
Physical control format indicator channel — signals how many OFDM symbols the control region spans (CFI).
PHICH
Physical hybrid-ARQ indicator channel — carries HARQ ACK/NACK for uplink grants.
PDCCH
Physical downlink control channel — carries DCI scheduling grants in CCEs built from REGs.
PDSCH
Physical downlink shared channel — user data in the remaining available REs.

Configurable parameters

Adjust duplex mode (FDD or TDD), channel bandwidth, cyclic prefix, CFI, PHICH configuration, cell ID, MBSFN subframes and antenna ports. The grid updates instantly and supports shareable links to any configuration. For 5G NR, see the companion 5G NR resource grid tool.

The other tools are in the lab. Uplink, 5G, and the PHY calculators. Code TRIAL.
Open Resource Grid Lab

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