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4G LTE
3GPP TS 36.213

LTE CQI Calculator

Bidirectional mapping between Signal-to-Interference-plus-noise Ratio (SINR) and Channel Quality Indicator (CQI) indices for LTE and 5G NR.

References: 3GPP TS 36.213 Section 7.2.3 Table 7.2.3-1 (CQI Definition), TS 36.101 (SINR requirements)
SINR to CQI Calculator
Enter SINR value or CQI index for bidirectional lookup

Range: -10 to 30 dB

Direct CQI lookup

CQI reporting mode

-10 dB0 dB10 dB20 dB30 dB
CQI 11
Out of RangePoorFairGoodVery GoodExcellent
SINR 15.0 dB → CQI 11

CQI Index: 11

64QAM
Input SINR:15.0 dB
Report Mode:wideband
Modulation:64QAM
Code Rate:567/1024 = 0.5537
Spectral Efficiency:3.3223 bits/symbol
Recommended MCS:MCS 20
Expected BLER:10%

Quality: Very Good

Very good channel quality - Excellent throughput, suitable for 4K video and high-speed downloads

Estimated Throughput (20 MHz, SISO):

Peak (theoretical):55.81 Mbps
Realistic (with overhead):39.07 Mbps

Assumes 100 PRBs, 12 subcarriers/PRB, 14 symbols/subframe. Overhead includes control channels and reference signals.

Suitable Use Cases:

  • 4K video streaming
  • High-speed downloads
  • Cloud gaming
  • Large file transfers
Excellent Conditions
64QAM modulation indicates very good SINR and low interference. Typically achieved near cell center with optimal RF conditions.
LTE CQI Reference Table
Complete CQI table (0-15) with SINR thresholds and modulation schemes
CQIModulationCode Rate × 1024Code RateEfficiencySINR Range (dB)MCSBLER
0
N/A--0.0000Out of range-100%
1
QPSK780.07620.1523-6.7 to -4.7010%
2
QPSK1200.11720.2344-4.7 to -2.3010%
3
QPSK1930.18850.3770-2.3 to 0.2210%
4
QPSK3080.30080.60160.2 to 2.4410%
5
QPSK4490.43850.87702.4 to 4.3610%
6
QPSK6020.58791.17584.3 to 5.9810%
7
16QAM3780.36911.47665.9 to 8.11110%
8
16QAM4900.47851.91418.1 to 10.31310%
9
16QAM6160.60162.406310.3 to 11.71510%
10
64QAM4660.45512.730511.7 to 14.11810%
11
64QAM5670.55373.322314.1 to 16.32010%
12
64QAM6660.65043.902316.3 to 18.72210%
13
64QAM7720.75394.523418.7 to 21.02410%
14
64QAM8730.85255.115221.0 to 22.72610%
15
64QAM9480.92585.5547≥ 22.72810%
About CQI

What is CQI?

Channel Quality Indicator (CQI) is a measurement reported by the UE to inform the eNodeB about the downlink channel quality. The eNodeB uses CQI to select the appropriate modulation and coding scheme (MCS) for optimal throughput.

CQI Reporting:

  • Wideband CQI: Single CQI value for entire system bandwidth
  • Subband CQI: Different CQI per subband (frequency selective)
  • Reporting Modes: Periodic or Aperiodic (triggered by eNodeB)
  • Update Rate: Typically 5-10 ms for periodic reports

CQI Index Meaning:

  • 0: Out of range - no transmission recommended
  • 1-6: QPSK modulation - poor to moderate signal
  • 7-9: 16QAM modulation - good signal
  • 10-15: 64QAM modulation - excellent signal
Link Adaptation

Process:

  1. UE measures downlink channel quality (RSRP, RSRQ, SINR)
  2. UE calculates appropriate CQI based on measurements
  3. UE reports CQI to eNodeB via PUCCH or PUSCH
  4. eNodeB selects MCS based on reported CQI
  5. eNodeB schedules downlink transmission with selected MCS

SINR to CQI Mapping:

Typical SINR thresholds for modulation schemes:

  • < -6.7 dB: No transmission (CQI 0)
  • -6.7 to 5.9 dB: QPSK (CQI 1-6)
  • 5.9 to 11.7 dB: 16QAM (CQI 7-9)
  • > 11.7 dB: 64QAM (CQI 10-15)

CQI and BLER:

CQI is selected to achieve a target Block Error Rate (BLER) of ~10% on the first transmission, allowing HARQ retransmissions to correct errors.