5G NR SINR Measurement Mapping
SINR (Signal to Interference plus Noise Ratio) is the ratio of the desired signal power to the sum of interference and thermal noise. In 5G NR it is the primary driver of MCS selection and therefore of achievable throughput.
SINR is reported as an integer index 0 to 127 mapped to a dB value per TS 38.133 §10.1.16. Resolution is 0.5 dB. The dB range spans -23 to +40.
Last verified 2026-04-15 against 3GPP TS 38.133 v18.3.0 §10.1.16 · Release 18
3GPP formula (TS 38.133 §10.1.16): SINR_dB = 0.5 * index - 23
SINR to modulation expectation
| Quality | SINR (dB) | Expected modulation |
|---|---|---|
| Excellent | >= 20 | 256-QAM |
| Good | 13 to 20 | 64-QAM |
| Fair | 0 to 13 | 16-QAM |
| Poor | -5 to 0 | QPSK |
| Very poor | < -5 | Out of coverage |
Capturing SINR on Android with HiCellTek
HiCellTek RF Monitor displays SS-SINR and CSI-SINR in real time for the serving cell. The trace is stored for post session analysis and exportable to Excel, CSV, and QMDL.
Frequently asked questions
What is SINR in 5G NR?
Signal to Interference plus Noise Ratio, the ratio of the desired target signal to the sum of thermal noise and interference from neighboring cells. It is the primary driver of MCS selection and therefore throughput.
What is the SINR reporting range?
Per TS 38.133 §10.1.16, SS-SINR and CSI-SINR reporting indices run from 0 to 127. The dB range is -23 to +40 in steps of 0.5 dB.
What SINR is needed for 256-QAM?
At least 22 dB SINR is typically required for the top 256-QAM MCS rows in Table 2. Below that, the scheduler typically backs off to 64-QAM or lower.
How does SINR relate to MCS?
Higher SINR allows higher MCS which means more bits per symbol. SINR is the main input the scheduler uses to select MCS for each UE every TTI.
Is SINR measured on RSRP signals?
SS-SINR is measured on the SSS. CSI-SINR is measured on CSI-RS. Both are defined in TS 38.215 and their reporting ranges in TS 38.133.
Can SINR be negative?
Yes. Negative SINR means noise plus interference is larger than the target signal. Modern LDPC coding in NR can decode at SINR below 0 dB with repetition, though throughput drops accordingly.