Example Data Table
| Scenario |
RB |
NF |
SINR |
Branches |
Combining |
Typical use |
| Cell edge uplink |
6 |
4.5 dB |
-8 dB |
2 |
MRC |
Narrow coverage check |
| Wide bearer test |
50 |
5 dB |
-6 dB |
2 |
MRC |
10 MHz occupied noise estimate |
| Four branch site |
100 |
4 dB |
-5 dB |
4 |
EGC |
Diversity comparison |
| Lab reference |
25 |
3 dB |
-9 dB |
1 |
None |
Single receiver baseline |
Formula Used
Noise bandwidth: BW = RB × 180,000 Hz, or manual BW × 1,000,000 Hz.
Thermal noise: N = -174 + 10log10(BW Hz).
Receiver noise: RN = N + noise figure.
Practical combining gain: gain is estimated from branch count, method, branch imbalance, and antenna correlation.
LTE sensitivity: Sensitivity = RN + required SINR + losses + margins - combining gain - external gain.
Link margin: Link margin = measured signal - calculated sensitivity.
How to Use This Calculator
- Enter a scenario name for reports and exports.
- Select LTE resource blocks or type a manual occupied bandwidth.
- Add receiver noise figure and the required SINR.
- Choose the diversity branch count and combining method.
- Add correlation, branch imbalance, losses, and design margins.
- Enter the measured signal level to calculate link margin.
- Press calculate, then review the result, table, and Plotly chart.
- Use CSV or PDF export for records and planning notes.
Understanding LTE Sensitivity Combining
LTE sensitivity shows the weakest signal a receiver can decode while meeting the chosen SINR and quality target. It is not a fixed number. It changes with bandwidth, noise figure, implementation margin, interference, and the diversity method used by the receiver.
Why bandwidth matters
Every LTE resource block adds thermal noise. A narrow allocation has a lower noise floor. A wide allocation carries more data, but it also collects more noise. That is why sensitivity becomes less negative when bandwidth grows. The calculator uses occupied noise bandwidth, not only the marketed channel size.
Combining gain explained
Multiple receive branches can improve sensitivity. Maximum ratio combining usually gives the highest gain because it adds branch power with weighting. Equal gain combining is slightly weaker. Selection combining keeps the best branch and discards the others. Real networks also suffer from branch imbalance and antenna correlation, so the practical gain is lower than the ideal value.
Using margins carefully
Margins protect a link budget from uncertainty. Implementation margin covers hardware limits, quantization, and demodulation losses. Interference margin covers neighboring cells and uplink noise rise. Cable, duplexer, and body losses raise the required input level. Extra front end gain lowers it, but it can also reduce linearity if used badly.
Planning insight
A good sensitivity study compares several branch counts. It also checks the result against the measured signal at the receiver connector. Positive link margin means the receiver has headroom. Negative margin means the design needs lower noise, better antennas, less loss, narrower bandwidth, or a stronger signal.
Practical workflow
Start with the LTE resource block count or the exact occupied bandwidth. Enter the receiver noise figure and required SINR from your modem target. Then choose the combining method, branch count, correlation, and imbalance. Finally add losses and margins. Use the chart to see how diversity changes the limit. Export the results for design reviews, site notes, and acceptance reports.
Important limits
The output is an engineering estimate. It does not replace lab conformance testing. Receiver algorithms, channel models, fading speed, coding rate, and reference sensitivity requirements can shift the final number. Treat the result as a planning baseline.
FAQs
1. What is LTE receiver sensitivity?
It is the minimum input signal level a receiver needs to decode data at the selected SINR, bandwidth, and quality target. A more negative value means better weak signal performance.
2. Why does bandwidth change sensitivity?
Wider bandwidth collects more thermal noise. More noise raises the required input signal. Narrow resource allocations usually produce better sensitivity values than full bandwidth allocations.
3. What does combining gain mean?
Combining gain is the receiver improvement from using multiple branches. It depends on branch count, combining method, correlation, and imbalance between antenna paths.
4. Is MRC better than selection combining?
Usually yes. Maximum ratio combining weights and adds branch signals. Selection combining uses only the strongest branch, so its practical gain is normally lower.
5. How should I enter antenna correlation?
Use zero for independent branches. Use higher values when antennas are close, similarly polarized, or affected by shared fading. Higher correlation reduces diversity benefit.
6. What is implementation margin?
It is extra allowance for nonideal receiver behavior. It can cover demodulator loss, quantization, calibration limits, hardware variation, and model uncertainty.
7. Why is link margin important?
Link margin compares measured signal with calculated sensitivity. Positive margin means the signal is above the receiver limit. Negative margin suggests coverage risk.
8. Can this replace lab testing?
No. It is a planning calculator. Use it for estimates, comparisons, and reports. Validate final products with controlled receiver tests and standard procedures.