In any wireless network, signal strength plays a critical role in performance. One of the most common measurements used to evaluate signal quality is Received Signal Strength Indicator (RSSI). Whether you’re setting up Wi-Fi, deploying IoT devices, or optimizing a cellular network, understanding RSSI helps you diagnose connectivity issues and improve reliability.
What is RSSI?
RSSI (Received Signal Strength Indicator) is a way to measure how strong a wireless signal is when it’s received by your device. A stronger RSSI means clearer and more reliable connection on your phone, laptop or router, while a weaker RSSI increases the risk of dropped calls, slower downloads, or glitches in your Bluetooth devices.
RSSI is typically measured in decibels (dBm) and can range from -100 dBm (weakest signal) to 0 dBm (strongest signal). The closer the RSSI value is to 0 dBm, the better the signal strength. An RSSI of -30dBm, for instance, means better connection quality and faster data transfers on your device, while an RSSI of -90dBm can create dropped connections, buffering videos, or slow downloads.
In Wi-Fi, RSSI helps you understand your:
- Signal strength: The stronger the RSSI, the faster and more stable your internet connection from Wi-Fi will be. Low RSSI means a weaker signal, leading to slower speeds and more interference.
- Network coverage: A high RSSI means the device is closer to the router or other Wi-Fi transmitter, whereas a low RSSI might indicate you are too far from the router or there are obstacles (for example, walls) weakening the signal.
- Troubleshooting: Wi-Fi devices often use RSSI values to make decisions, such as when to switch between access points in a mesh network or whether to boost signal strength. It can be a key metric for troubleshooting connectivity issues.
Technicians and network engineers often use RSSI for:
- Site surveys and network design: During the planning phase of a wireless network, network engineers use RSSI measurements to determine the best locations for access points (APs). This minimises dead zones, and ensures the space receives a strong and consistent signal.
- Optimisation of Wi-Fi coverage: Ensure Wi-Fi coverage is reliable and consistent throughout a building or area. They may then relocate access points, increase transmission power, or deploy additional APs (access points) to improve coverage.
- Run diagnostics: RSSI is one of the critical metrics used to diagnose network issues related to weak signal strength or poor performance.
How does RSSI work?
Wireless devices have small sensors that detect the energy of the signal. When the device receives the signal, it calculates its strength and assigns it an RSSI value.
This value isn’t the same as the speed of your connection, but it tells the device how reliable the signal is. If the RSSI is strong, the device knows it’s getting a clear signal and can use it efficiently, while if the RSSI is weak, the device might struggle, causing slower speeds or dropped connections.
RSSI works in real-time, constantly updating as the device moves closer to or farther from the signal source. For example, if you’re walking away from a WiFi router, the RSSI will drop, signaling to your device that the connection is weakening.
This helps the device decide whether it needs to switch to a stronger signal or alert you that the connection is poor.
What is a Good and Bad RSSI Signal Strength / Value?
A good RSSI signal strength typically falls between -30 dBm and -60 dBm. This range allows for fast and reliable connectivity, making it ideal for activities such as 4K streaming, online gaming, and video conferencing. Users with an internet connection within this range can expect high-speed internet with minimal buffering or interruptions.
An average RSSI signal strength is between -60 dBm to -70 dBm. While it may not be as fast or reliable as stronger signals, it is still suitable for most common activities like browsing the web, emailing, and standard-definition video streaming. However, users may experience slower speeds or occasional buffering when carrying out high-bandwidth tasks like HD streaming or large file downloads
A poor RSSI level is generally below -70 dBm, with anything below -80 dBm often resulting in a very unreliable connection. At this level, users may experience frequent connection drops, slow speeds, and buffering when attempting activities such as video streaming, online gaming, or even basic web browsing.
How to Improve RSSI
If RSSI readings are weak, consider the following:
Move Closer to the Router
The simplest way to improve your RSSI is to reduce the distance between your device and the WiFi router. WiFi signals weaken as they travel, so being too far from the router can lead to a lower RSSI. Try to use your device in the same room or areas with fewer walls and obstructions between you and the router. The closer you are, the stronger the signal will be.
Reduce interference
Devices like microwaves, cordless phones, and neighbouring Wi-Fi networks can interfere with your signal. Switch your router to a less crowded channel, or move the router away from these sources of interference. Using 5 GHz instead of 2.4 GHz can also help.
Upgrade Your Router or Antennas
Older routers may not have the same range or power as newer models. Upgrading to a modern router with better antennas and support for newer WiFi standards (like WiFi 6) can greatly improve your RSSI. Some routers also allow you to replace or adjust their antennas to boost the signal in specific directions.
Use a WiFi Extender or Mesh System
If your router’s signal can’t reach certain parts of your home, a WiFi extender or mesh system can help. These devices work by repeating or redistributing the WiFi signal to areas with poor RSSI. A mesh WiFi system is especially useful for large homes or areas with lots of walls, as it provides a seamless and reliable connection throughout the space.
Update your firmware
Your router’s firmware is the software that controls its functions and features. Sometimes, the manufacturer releases updates that can improve the performance, stability, and security of your router.
Adjust Your Device or Router Placement
Sometimes, small changes in placement can make a big difference. Place your router on a high, flat surface, like a shelf, to maximize its signal range and avoid placing it on the floor or near thick walls. Try to also keep your device in an open area and avoid placing it in corners or behind large objects.
Change your Wi-Fi channel and frequency band:
Your Wi-Fi network operates on a certain channel and frequency band, which can affect its speed and reliability. If there are many other Wi-Fi networks in your area using the same channel or band, they can interfere with each other and cause congestion.
Conclusion
Received Signal Strength Indicator (RSSI) is a fundamental measurement in wireless networking. It provides insight into how strong a signal is at the receiver and plays a vital role in maintaining stable connections. However, RSSI alone does not determine overall network quality. Combining RSSI with other metrics like SNR delivers a clearer picture of wireless performance.
By understanding RSSI and monitoring it correctly, network administrators can improve coverage, reduce downtime, and ensure reliable connectivity across residential, commercial, and industrial environments.
