Likewise your device UI can signal to the end-user that they may wish to move the device closer to the cell. Quectel’s values aren’t totally qualitative: they also give an indication of how the signal strength and quality drops off as the modem moves away from the tower toward the edge of its cell. You can translate these values into a four-bar indicator of the kind shown by cellphones. How can an application make use of these values? Using the table above - and assuming you’re working with a Quectel BG96 modem, of course - you can read back the RSRP and RSRQ values after the modem has run been connected for a short time and use them to present a ‘connection quality’ indicator to end-users such as a line of LEDs, a single multi-color LED, or an on-display icon. These quality values will depend on the particular abilities of the modem: essentially how well it can extract signal. Other vendors will have different quality values for given ranges of RSRP and RSRQ. For the Quectel BG96, the cellular modem supported by the imp006 module, the AT command QCSQ (which stands for Query and Report Signal Strength) can be used: Now, because the RSRP and RSRQ values are continuously being determined by the modem, they can be read back by the application. RSRP and RSRQ are the only values you should use to compare the signal-handling performance of modems from different suppliers because only these are part of the LTE specification and are defined using signals sent by every cell tower. There are other values that are often discussed in the context of cellular signal strength, including RSSI and SINR, but these are not formally defined in the LTE specification and so are not comparable across modems from different manufacturers. If two towers’ RSRP values are too close to call, the modem uses RSRQ as the basis for its choice. With RSRP values for all the nearby towers, the modem chooses the tower with the best RSRP. A connection with a high RSRQ should be good, even if the RSRP is low: the modem is able to extract the information in the weak signal because of minimal noise. The LTE specification defines a second value, RSRQ (Reference Signal Received Quality), as the ratio of the carrier power to the interference power: essentially this is a signal-noise ratio measured using a standard signal. the closer to zero it is, the higher the power of the signal. RSRP values, presented in dBm, are always negative, and the higher the number, ie. This is the measured power of the LTE reference signals spread across the broadband and narrowband portions of the spectrum. LTE technology includes reference signals which a modem uses to assess the state of the connection to a given cell tower in a standard way.Ī modem determines which tower to connect to on the basis of a value called RSRP (Reference Signal Received Power). Cellular modems - ‘User Equipment’ (UE) in the jargon - continuously monitor signals transmitted by all nearby cell towers so that they can always connect to the one with the best signal. Work with the Breakout SDK for Narrowbandįortunately, cellular communications technology was developed specifically to cater for these factors. Get Started with Machine-to-Machine SMS Commands Get Started with the Programmable Asset Tracker How to Obtain a Programmable Asset Tracker Get Started with the Microvisor Nucleo Development Board How Super SIM Devices Connect to Cell Networks Monitor Super SIM Connection Events using AWS ElasticSearch and Kibanaīest Practices for Cellular Module Registration Set Super SIM’s Network Attach Priority List Get Started with Super SIM Connection Events Get Started with Super SIM eSIM Profiles for eUICCs Get Started with IP Commands and the Raspberry Pi Pico Get Started with IP Commands and the Raspberry Pi 4 Get Started with SMS Commands and the Raspberry Pi Pico Get Started with SMS Commands and the Raspberry Pi 4 Get Started with the Raspberry Pi 4 and Sixfab Base Hat Get Started with the Raspberry Pi 4 and Waveshare 4G Hat
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