Signal Quality: RSSI, RSRP and RSRQ Explained

Estimated reading time: 5 minutes

Signal quality indicates how well a radio signal can be decoded and maintained for reliable communication. It reflects clarity and stability, accounting for factors that may disrupt transmission. 

Crucial for consistent data transmission, signal quality affects cellular network performance. Factors that degrade signal performance and result in slower data transfer and a less dependable connection include:

• Interference
• Network congestion
• Distance from the cell tower

A stable connection quality is necessary for dependable Internet of Things (IoT) connectivity. Consistent communication ensures the reliable operation of an IoT device and its connected applications. 

Poor signal performance can lead to:

• Dropped connections
• Increased latency
• Delayed or incomplete data reporting
• Increased power consumption from retransmissions

Strong signal performance ensures that devices: 

• Transmit data reliably
• Maintain stable connections
• Operate with maximum efficiency 

How IoT Devices Monitor Signal Quality

IoT devices continuously measure signal quality through their built-in radio transceivers and antennas. Manual sampling is not required. Operators review this information through device reports or diagnostic tools and dashboards.

By analyzing signal metrics, operators can identify coverage gaps and interference. Insights like these help them remotely optimize device placement and reduce costly downtime. This strategy enhances performance and maintains steady data transmission.

What Is the Received Signal Strength Indicator?

Received Signal Strength Indicator (RSSI) is a common metric for evaluating wireless signal strength. It’s used across multiple technologies, including:

• 2G
• 3G
• Wi-Fi

Expressed in decibels per milliwatt (dBm), RSSI values typically range from around -110 dBm (poor) to -50 dBm (excellent). However, RSSI reporting varies across technologies. In LTE, the standardization is less comprehensive than in Wi-Fi, which can affect interpretation.

RSSI measures the total power received by a device from a signal source. It includes not only the intended signal but also interference and background noise. Because it reflects overall power, it’s often used to estimate the vicinity to a transmitter or determine the proximity to a signal source. 

RSSI alone does not provide a complete picture of signal quality or stability. A strong RSSI could still mean poor performance if interference is present. LTE and 5G networks pair RSSI with more precise metrics, such as RSRP and RSRQ, to provide a comprehensive picture of connection health. RSSI is useful for detecting signal presence and strength, but it is only one metric when assessing network quality.

What Is Reference Signal Received Power?

Reference Signal Received Power (RSRP) is a key measure of signal strength in LTE and 5G New Radio (NR) networks. It measures the average power of reference signals transmitted by a cell tower. These signals are essential for maintaining stable connections.

RSRP is crucial for:

• Cell handover decisions
• Network optimization
• Coverage analysis

Unlike RSSI, which captures total received power including interference and noise, RSRP focuses on the strength of the reference signal itself. This makes it a more precise indicator of cellular network signal strength. Expressed in decibels per milliwatt (dBm), RSRP values typically range from about -140 dBm (very weak) to -44 dBm (very strong).

In IoT deployments, RSRP is a primary measure of whether a device can maintain a consistent connection. Although RSRP indicates signal strength, it does not account for interference or overall signal quality. Pairing it with RSRQ and other metrics provides a complete picture of connection health.

What Is Reference Signal Received Quality?

Reference Signal Received Quality (RSRQ) is principally used in LTE and 5G NR networks.  It reflects overall connection quality by evaluating signal strength in the context of interference and noise. 

RSRQ is particularly useful for:

• Assessing overall connection quality
• Making handover decisions at cell edges
• Optimizing network performance in noisy environments

RSRQ compares the reference signal strength (RSRP) to the total received power (RSSI), which includes interference and noise. Accounting for both signal strength and interference, RSRQ serves as a strong indicator of signal clarity and network conditions. Expressed in decibels (dB), typical values range from about -19.5 dB (poor) to -3 dB (excellent).

In LTE-based IoT systems, RSRQ helps identify degraded performance caused by interference, even when RSRP appears strong. This makes it an essential metric for operators who need to maintain constant connectivity and minimize downtime. RSRQ is often analyzed alongside RSSI and RSRP for a complete picture of network health.

Network Performance

Cellular networks form the backbone of modern IoT applications. They deliver high-speed, low-latency connectivity across vast areas. However, performance can vary significantly depending on signal conditions. By monitoring key metrics such as RSSI, RSRP and RSRQ, operators and engineers can:

• Identify weak coverage areas
• Optimize antenna placement
• Improve device handover strategies
• Ensure consistent data transmission

These metrics are vital to low-power wide-area (LPWA) technologies like LTE-M and narrowband IoT (NB-IoT), which prioritize long-range, battery-efficient communication. 

In 5G networks, it’s necessary to evaluate signal strength and quality due to higher-frequency bands and advanced features such as network slicing. Proactive performance monitoring helps maintain stable connections and support the growing demands of IoT ecosystems.

Optimize Your Deployment with Telit Cinterion

Reliable connectivity is the foundation of every successful IoT deployment. Telit Cinterion delivers industry-leading modules, data plans and cloud services designed to keep devices connected, wherever they are. 

The NExT™ connectivity platform simplifies IoT device management. Our security by design approach ensures data integrity across networks. Whether optimizing signal strength or deploying devices in challenging environments, we provide the tools and expertise to succeed.

Telit Cinterion’s modules and services help you optimize signal quality and ensure consistent IoT performance. Connect with an expert today.