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Overview
Reliable cellular communication depends heavily on antenna selection, installation quality and RF environment optimisation. This guide explains how to improve LTE, 5G, LTE-M and NB-IoT signal reception in IoT applications using correct antenna selection, positioning and survey analysis techniques.
Modern IoT deployments rely heavily on reliable cellular communication.
However, many connectivity problems are caused not by the modem itself, but by:
Even small installation improvements can significantly improve:
This guide explains practical methods for improving cellular signal reception in embedded and industrial IoT systems.
This guide explains:
Expected Result
At the end of this guide the user will understand how to identify and improve poor cellular signal performance in IoT applications.
Cellular performance depends on more than just signal strength.
Three key measurements are commonly used:
| Measurement | Description |
|---|---|
| RSRP | Reference Signal Received Power |
| RSRQ | Reference Signal Received Quality |
| SINR | Signal to Interference plus Noise Ratio |
Together these determine:
Strong signal strength does not always mean good performance.
| Condition | Typical Result |
|---|---|
| Strong signal + good quality | Excellent performance |
| Strong signal + poor quality | Congestion or interference issues |
| Weak signal + good quality | Usable with antenna improvements |
| Weak signal + poor quality | Unstable operation |
| LTE RSRP Signal Quality Scale (dBm) | |||
| Poor | Fair | Good | Excellent |
| < -110 | -110 to -100 | -100 to -90 | > -90 |
| Min -140 dBm | Max -44 dBm | ||
| LTE RSRQ Signal Quality Scale (dB) | |||
| Poor | Fair | Good | Excellent |
| < -15 | -15 to -12 | -12 to -8 | > -8 |
| Min -19.5 dB | Max -3 dB | ||
SINR indicates how much usable signal exists compared to interference and noise.
| SINR Signal Quality Scale (dB) | |||
| Poor | Fair | Good | Excellent |
| < 0 | 0 to 10 | 10 to 20 | > 20 |
| Min -20 dB | Max 30+ dB | ||
Cellular signal degradation may occur due to:
Outdoor antenna placement usually provides significantly better performance.
| Installation Type | Typical Behaviour |
|---|---|
| Indoor antenna | Higher attenuation and reflections |
| Outdoor antenna | Improved signal visibility |
| Roof mounted antenna | Best overall coverage |
| Basement installation | Severe attenuation possible |
Different materials attenuate RF signals differently.
| Material | Typical RF Impact |
|---|---|
| Glass | Low to moderate attenuation |
| Brick | Moderate attenuation |
| Concrete | High attenuation |
| Metal cladding | Very high attenuation |
| Low-E glass | Significant attenuation possible |
Small antenna movements can significantly affect signal quality.
Good antenna placement should:
| Recommendation | Benefit |
|---|---|
| Mount higher where possible | Improved signal visibility |
| Position near windows | Reduced penetration losses |
| Move away from metalwork | Reduced reflections |
| Avoid electrical noise sources | Reduced interference |
| Test multiple positions | Identify optimum location |
Many antennas depend on a suitable conductive ground plane.
Poor ground plane conditions can reduce:
Ground plane behaviour becomes particularly important for:
RF cable losses directly reduce received signal strength.
As frequency increases:
This becomes increasingly important for:
| Recommendation | Benefit |
|---|---|
| Use shortest practical cable | Reduced attenuation |
| Use low loss cable | Improved RF efficiency |
| Avoid unnecessary adaptors | Reduced insertion loss |
| Minimise connector count | Improved reliability |
Modern LTE and 5G systems commonly use:
Multiple Input Multiple Output (MIMO)
MIMO improves:
| Recommendation | Purpose |
|---|---|
| Maintain antenna separation | Reduce antenna coupling |
| Use matched antennas | Balanced performance |
| Avoid cable imbalance | Improved diversity operation |
| Use correct polarisation | Improved MIMO efficiency |
Directional antennas focus RF energy toward a specific cell tower.
They are useful when:
| Type | Typical Use |
|---|---|
| Omnidirectional | General IoT and mobile installations |
| Directional | Weak signal fixed installations |
LTE-M and NB-IoT devices often operate in challenging RF environments.
These applications commonly require:
Improving antenna placement can significantly improve:
Vehicle environments introduce:
Roof-mounted antennas generally provide the best performance because they maximise ground plane efficiency and signal visibility.
Common interference sources include:
Unlike GNSS systems which benefit from RHCP/LHCP multipath rejection, cellular systems may still receive reflected signals with similar polarisation characteristics.
This can create:
As a result, small antenna movements may significantly change LTE or 5G signal quality.
Cellular surveys allow installers to identify:
SNYPER and SENTRY survey tools can help optimise deployments before final installation.
| Step | Action |
|---|---|
| 1 | Perform initial survey |
| 2 | Compare operators |
| 3 | Review RSRP, RSRQ and SINR |
| 4 | Test antenna positions |
| 5 | Reduce cable losses |
| 6 | Optimise antenna mounting |
| 7 | Repeat survey validation |
| Mistake | Consequence |
|---|---|
| Mounting antenna indoors | Reduced signal quality |
| Using long RF cables | Signal attenuation |
| Poor antenna grounding | Reduced efficiency |
| Incorrect antenna type | Poor coverage |
| Ignoring signal quality | Unstable performance |
| Poor MIMO separation | Reduced throughput |
| Step | Purpose |
|---|---|
| Survey environment | Identify network conditions |
| Optimise antenna placement | Improve signal quality |
| Reduce cable losses | Increase RF efficiency |
| Improve grounding | Improve antenna behaviour |
| Validate installation | Confirm reliable operation |
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