Signal Strength (RSSI, RSRP, SINR)

Understanding the Metrics Behind Your Signal

Once you start diving into signal quality, you’ll come across three common terms: RSSI, RSRP, and SINR. These are the key performance indicators that your router or IoT device uses to measure how well it’s connected to the mobile network.

But while they may seem like technical jargon, understanding what they mean — and how to improve them — can make a real difference to the reliability of your connectivity.

RSSI – Total Power, Not Total Quality

RSSI (Received Signal Strength Indicator) measures the overall power of all signals received by the antenna — including both usable signals and interference.

While it’s often shown in device dashboards or router admin panels, it’s not a true reflection of signal quality on its own. A high RSSI could still mean a poor connection if the noise level is also high.

👉 Use it only as a rough guide, and don’t rely on RSSI alone when deciding where to place your device or antenna.

RSRP – The Key Signal Strength for LTE

RSRP (Reference Signal Received Power) measures just the power of the LTE reference signals, making it a much more accurate reflection of true signal strength.

This is the number to watch when positioning your external antenna. A stronger RSRP generally means:

• Better connection stability
• Fewer dropouts
• Higher throughput speeds

Improve RSRP by:

• Installing an antenna where it may receive a better signal compared to the router location.
• Placing your router or antenna near a window or outdoors
• Avoiding metal enclosures or signal-blocking materials

For critical IoT applications — especially when using Fixed IP SIMs, Multinetwork SIMs, or Roaming SIM cards — a strong RSRP ensures a solid foundation for remote access and data transfer.

SINR – The Signal’s Cleanliness Matters

SINR (Signal to Interference + Noise Ratio) is arguably the most important metric for signal quality. It tells you how much of your signal is usable vs how much is lost to interference or noise.

A poor SINR can result in:

• Slow data speeds
• High latency
• Connection timeouts

Improve SINR by:

• Using a shielded directional antenna to block out neighbouring tower interference
• Raising the antenna to avoid ground-level reflections
• Ensuring there’s a clear line-of-sight to the cell tower where possible

A good SINR is essential when using your router for VoIP, live video feeds (such as with CCTV systems), or time-sensitive machine-to-machine communications.

Tips for Optimising Signal Performance

When setting up any 4G or 5G IoT router, it’s not just about plugging in and hoping for the best. Signal quality can vary dramatically depending on the local environment, building materials, and even the direction your antenna faces.

To maximise uptime and performance:

• Use external antennas — ideally with adjustable mounting brackets
• Choose Multinetwork or Roaming IoT SIM cards that connect to the strongest local network
• Monitor RSRP and SINR values in real time during installation
• Consider antenna extension cables to place antennas at roof height or near windows

Millbeck can also assist in preconfiguring routers with network monitoring tools that help installers fine-tune performance from day one.

Why This Matters for IoT & Remote Deployments

Signal quality isn’t just about speed — it’s about reliability. In remote or mission-critical M2M deployments, a poor connection can lead to missed alerts, failed telemetry, or expensive site visits.

By understanding RSSI, RSRP, and SINR — and how they interact — you can make smarter decisions about your setup and avoid unnecessary downtime.

Need Help? Speak to Millbeck

Whether you’re deploying a single IoT router or managing thousands of connected devices across the UK and beyond, Millbeck can help.

We supply:

• Industrial routers with antenna options for any environment
• IoT SIM cards with Fixed IP or Private IP options
• Roaming and Multinetwork SIMs designed for maximum uptime
• Preconfigured hardware ready to install

If you’re unsure whether your current setup is working as well as it could — or you just need guidance on signal metrics — get in touch and we’ll be happy to help.