Most people focus on signal strength when they're having connection problems. Signal strength is measured in dBm, typically ranging from -50 dBm (excellent) to -120 dBm (extremely poor). But signal strength is only part of what determines how well your phone actually works.
Signal quality often matters more than signal strength when it comes to your actual experience. Even small improvements in signal quality can result in significantly faster data speeds.
What's the Difference Between Signal Strength and Signal Quality?
Cell signal strength measures how strong the signal is, while signal quality measures how clear or clean the signal is. Both are important-strong signal doesn't always mean good performance if the quality is poor.
Signal Strength (RSRP or RSSI)
Signal strength tells you how powerful the signal is, usually shown in dBm (decibel-milliwatts). A higher (closer to zero) number means a stronger signal-like -60 dBm is better than -100 dBm. It affects how far the signal can travel and whether your cell signal booster can pick it up. However, strength alone isn't enough for good calls or fast data.
Signal Quality (SINR or RSRQ)
Signal quality shows how clean the signal is, factoring in interference and noise. High-quality signal means fewer dropped calls and better data speeds. It's measured using SINR or RSRQ, and higher values are better. Even with a strong signal, poor quality can lead to slow or unstable connections.
Understanding Connection Metrics for Cellular Devices
Cell networks use four specific metrics to evaluate how well your phone connects to cell towers, and understanding these measurements can help you figure out why your phone isn't working properly even when it shows good signal.
Modern 4G and 5G networks rely on four primary metrics to evaluate signal performance. Each one tells you something different about your connection:
RSRP (Reference Signal Received Power) measures the actual power your phone receives from a specific cell tower. This metric ranges from -44 dBm (excellent) to -140 dBm (unusable). Here's what the numbers mean:
- Stronger than -80 dBm: excellent signal with maximum data speeds
- -80 dBm to -90 dBm: good signal strength
- -90 dBm to -100 dBm: fair to poor performance
- Weaker than -100 dBm: drastically reduced performance
RSRQ (Reference Signal Received Quality) tells you how clean your signal is by measuring both the signal power and the total interference. This quality measurement ranges from -3 dB (excellent) to -19.5 dB (unusable). The scale works like this:
- Better than -10 dB: excellent quality
- -10 dB to -15 dB: good quality
- -15 dB to -20 dB: fair to poor quality
SINR (Signal to Interference plus Noise Ratio) measures how much your desired signal stands out from background noise and interference. Unlike the other metrics, higher SINR values are better:
- Above 15 dB: excellent performance
- 10 dB to 15 dB: good data speeds
- 5 dB to 10 dB: fair performance
- Below 5 dB: poor connection quality
RSSI (Received Signal Strength Indicator) represents the total power your phone receives across the full channel bandwidth. While many apps display RSSI, it can be misleading because it includes noise and interference along with the actual signal you want.
Here's why these metrics matter: you might have an RSSI reading of -68 dBm that looks strong, but if your RSRQ is -16 dB and your SINR is only 1.8 dB, you'll still have terrible performance. This explains why your phone can show full bars but still drop calls or load web pages slowly.
Cell phone carriers focus on maximizing SINR at their cell sites because it directly impacts how much data their networks can handle and how fast your connection will be.
How to Measure Signal Strength and Quality on Your Device
Your phone's signal bars don't give you the real numbers you need to understand your connection. To see what's actually happening with your signal, you need to access the specific measurements that your phone is already collecting.
The most reliable way to check your actual signal metrics is through Field Test Mode, which is built into most smartphones. This diagnostic tool shows you the exact dBm readings and quality measurements that your phone uses behind the scenes.
For iPhone users, dial *3001#12345#* and press call. This opens a detailed dashboard showing your signal strength in decibel-milliwatts (dBm) instead of those misleading bars. If you're using iOS 18, look for the RSRP tab under both 5G and 4G sections to see your actual signal strength. On iOS 17, tap "LTE Rach Attempt" and check the RSRP tab for 4G signal strength values.
For Android devices, Field Test Mode is typically accessed through your phone's settings. Go to Settings > About Phone > Status/Network > SIM Status, where your signal strength appears under "Signal Strength". Some Android phones also allow access by dialing *#*#4636#*#*.
Field test readings give you exact measurements instead of those arbitrary bars. Here's what the numbers mean:
- -50 to -79 dBm = Excellent signal (4-5 bars)
- -80 to -89 dBm = Good signal (3-4 bars)
- -90 to -99 dBm = Average signal (2-3 bars)
- -100 to -120 dBm = Poor to very poor signal (0-1 bars)
Android users can also install apps like Network Cell Info Lite, which displays signal strength, quality metrics, and frequency bands as soon as you open it. These apps provide nearly real-time updates as you move around your location. LTE Discovery offers similar functionality with information about LTE, 4G, and 5G networks.
Before taking measurements, turn off WiFi to ensure you're getting accurate cellular signal readings. For the most useful information, test your signal in multiple locations around your home or office to identify areas with optimal connectivity.
Why Signal Quality Often Matters More Than Signal Strength
Your phone's signal bars focus on strength, but signal quality determines whether your calls actually work. This explains why you might have full bars but still deal with dropped calls, slow data speeds, and poor call quality. The truth is that signal quality measures matter more than raw signal strength.
Think of it like this: turning up the volume on a static-filled radio station just gives you louder static, not clearer sound. The same thing happens with cellular signals. Boosting a poor-quality signal only amplifies the problems. Research shows that 72% of cell phone users experience dropped calls occasionally, with 32% experiencing them regularly, often despite having what appears to be strong signal.
Signal quality tells you how clean and usable your connection is. Even with relatively weak signal strength, good quality signal enables stable connections. But a strong signal with poor quality leads to:
- Dropped calls mid-conversation
- Slow data speeds during peak usage times
- Audio distortion during voice calls
- Frequent disconnections from the network
The Signal-to-Noise Ratio (SNR) has the biggest impact on performance. This measurement compares your desired signal against background noise. Higher SNR values mean clearer communication channels-essentially, how well your device can distinguish legitimate cell signals from background interference. Networks generally recommend an SNR value of 20 dB or higher for data networks, while voice applications require at least 25 dB.
Cell tower congestion affects signal quality regardless of strength. At concerts or in dense urban areas, you might have full signal bars but terrible performance. This happens because too many devices compete for the same resources, degrading signal quality without affecting the displayed signal strength.
If you're only focusing on improving signal strength through location changes or boosters, you might not solve your connectivity issues. Unless the underlying signal quality improves alongside strength, performance problems typically persist.
Conclusion
Signal quality and signal strength work together to determine your cellular experience, but quality typically has the bigger impact on your daily phone use. When your calls drop despite full bars, the problem is usually signal quality, not strength. Understanding this distinction helps you solve connection problems that seem impossible to fix.
The metrics we've covered - RSRP, RSRQ, SINR, and RSSI - give you a complete picture of what's actually happening with your connection. Field Test Mode on your phone lets you see these real measurements instead of relying on those misleading signal bars. This knowledge helps you make better decisions about where to position yourself for the best connectivity.
Cell tower congestion, interference, and noise all affect signal quality regardless of how strong your signal appears. This explains why you might have terrible performance in crowded areas even with full bars, or why someone with fewer bars might have a better connection than you do.
If you're having persistent connection problems, focus on improving signal quality alongside signal strength. Simple solutions like moving to a different location, changing your phone settings, or using a signal booster can help. For more complex signal issues, understanding both metrics helps you troubleshoot more effectively.
If you have questions about improving your specific signal situation, call us at 800-590-3564 and we'll help you find the right solution for your needs.