How is a cellular signal measured? How to find out the exact cellular signal strength on iPhone

To the question What do these numbers mean in the signal level? (see photo) given by the author Dry out the best answer is Decibels (dB) are logarithmic units,
widely used in radio engineering to express the relationship of two quantities.
The ratio of voltages (U) and powers (P) of two signals in decibels can be
express it like this: N = 20 log (U1/U2) = 10 log (P1/P2)
If a certain reference value is used as one of the quantities in the relation
absolute value, then it becomes possible to express absolute values
in logarithmic units. For example, if we take as the reference value
power is 1 mW, then other absolute power values ​​can be expressed in
logarithmic units<дБм>(decibel to milliwatt) which are often
used in radio engineering. In this case, positive values ​​correspond to
levels exceeding the reference value, and negative - levels below the reference
meanings.
_________________________________________________________________-RxLev, signal level - level received via
this radio signal channel at the input to the telephone receiver. Measured in
decibels per milliwatt (dBm). Calculated using the formula RxLev = 10lg
Rx(mW) /1 mW. Since the received signal power is significantly less than 1 mW,
the resulting value is negative. Moreover, the smaller it is numerically, the signal
worse. In GSM cellular networks, the received signal strength varies by
within approximately −35 dBm - −111 dBm.
In Android level
signal is issued in ASU units
(Arbitrary Strength Unit),
The noise level is taken as 0 useful signal, i.e. -113dBm.
Formula
conversion from ASU to dBm:
(2 * ASU) – 113.
dBm and asu
Gradations of cellular signal strength with base station
(BS):
5. up to -75 dBm - reliable or normal communication in buildings;
4. -85…-75 dBm - reliable communication on the street and in transport;
3. -95…-85 dBm - average signal level (border zone);
2. -105…-95 dBm - low signal level (reception not guaranteed);
1. -110…-105 dBm -min signal level (communication on the verge of breaking).
__________________________________________________________________________-
Asu-arbitrary strength unit
wireless network signal level, my translation)) The signal in the pilot channel is continuously emitted by the BS, level
the power of this signal is constant and 4-6 dB higher than in direct channels
traffic. The subscriber station (SS) uses the pilot signal to acquire
carrier frequency (initial synchronization), after which it tracks it with
accurate to the phase and identifies the reference vibrations necessary for processing
signals of this BS upon reception.
The direct traffic channel is used to transmit voice messages,
data, service control information and signaling.
Gradations of the signal-to-noise ratio (asu) in the pilot channel:
I. asu at least 10 – the telephone can transmit voice;
II. asu at least 6-7 – the phone can transmit data.
A by-product of the search)))

The signal level is one of the most important characteristics for obtaining high Internet speed on a 3g/4g modem. In this article I will show you how to check the signal level of a 3g/4g modem using standard programs that come with the modem and third-party programs.

How to determine the signal level on a 3g/4g Beeline modem.

Launch the "USB modem" program, go to the "Settings" tab,

Select the "Modem Information" menu, on the right you will see the signal strength of your modem.

How to find out the signal level on a 3g/4g Beeline modem.

Launch the Megafon Modem program. Click "Help" - "Diagnostics".

Go to the Network Status tab. There you will see the modem signal level.

A universal program for determining the signal level of a 3g/4g modem.

The plugin is designed for convenient configuration of 3G modems and 3G antennas. The plugin can: show the signal level in dBm in large numbers (on the entire screen), as well as pronounce the signal level in Russian or English; determine the direction to the operator’s transmitting base station. The program works together with MDMA, i.e. launch the MDMA utility, then launch the plugin.

“Level Percentage” - Level in percentage
“Level as voice” - Voice level
“Voice R2” - Speak only when the signal level changes

The article will be useful for those who are choosing an antenna and equipment to strengthen the mobile 3G and 4G Internet signal, or a repeater to strengthen cellular communications.

The 3G/4G signal frequency is the initial parameter in choosing an antenna. For example, you may not even know the location of base stations on the ground - just catch the signal and determine the direction by level by rotating the antenna. But if you don’t know the frequency, you may not be able to catch the signal at all.

Important! It is recommended to carry out all testing at the point where the antenna is planned to be installed (with a laptop + modem, ideally on the roof), because indoors, the modem may not be able to pick up a signal in the 2600 MHz (4G) range, but for an outdoor antenna it is the most effective!
Due to the fact that the methods for determining the GSM/3G/4G/4G+ frequency are different, we will consider them separately.

1. Mobile method:

1. Android:
Attention! Turn off Wi-Fi!
To test the frequency, the built-in technical menu “Netmonitor” is used, which is called up with a personal code in each smartphone model. A list of Android phone numbers and codes such as *#0011# or *#*#4636#*#* or *#*#197328640#*#* can be found

For Samsung:Turn off Wi-Fi, and select 3G or 4G LTE mode. In the telephone number entry field, enter the combination: *#0011#, after which the phone will enter service mode with a report on the signal of the BS to which you are connected.

3G parameter values:

1. uarfcn(may be denoted as RX): Channel number identifying the frequency. If the value is from 10562-10838, then you have 3G/UMTS 2100 MHz. If 2937-3088, then this is 3G/UMTS 900 MHz. In our case uarfcn = 10687 , therefore frequency 3G = 2100.
   
2. EcIo (Ec/Io or Ec/No): the ratio of the signal level to the noise level (the higher the indicator, the better). The lower the load (the network is free), the closer the EcIo indicator tends to 0. As the number of subscribers increases, the throughput decreases - the ratio worsens down to -12..-14 dB, after which, according to the settings, a 3G->2G switch can occur. Perhaps you should choose the direction to a freer tower. For 4G this parameter is designated as CINR .
   
3. RSCP:(Reference Signal Received Power) The strength of the received signal that your device receives when connected to the BS. -70 good, -100 bad.
   

4G LTE values:

1. Band: The frequency at which the 4G network tower operates. There are 3 of them in total. In our case Band:7 this is the frequency 2600 MHz , If Band:3 That 1800 MHz, And Band:20- frequency 800 MHz. (Full list of frequency bands.)
2. RSSI: Base signal strength value At values RSRP= -120 dBm and below LTE connection may be unstable or absent altogether.
3. CINR: The ratio of the level of the useful signal to the airborne noise. Everything is simple here: the higher this value, the better the signal quality. If SINR below 0, the connection speed will be low, as this means that there is more noise in the received signal than usefulness, which increases the likelihood of losing the LTE connection.

1.1 ADDITIONAL APPLICATIONS FOR ADNROID:

Here, without a doubt, it is worth noting the CellMapper application, which is capable of identifying and displaying on the screen the operating frequency value, information about the tower, about neighbors, and displaying the tower on the map ( option should be enabled“Calculate GSM/UMTS/LTE frequencies”) As we already wrote, the frequency is displayed in the value Band. The signal level is indicated in the field Reference Signal Received Power(RSRP). To use the application, you must register for free on the website.

1.2 Displaying the signal level in standard USB Modem applications:

Information about the signal level is contained on almost any 3G/4G LTE modem; to do this, just study the menu.

2. Testing using a USB modem (the most reliable):

Nevertheless , the most effective, inexpensive and reliable way to establish the carrier frequency of an Internet signal remains a computer + modem with a HiLink or Stick . Below is the testing methodMDMA program using firmware Stick which is usually found on purchased locked modems of Russian telecom operators.

2.1 Working with the MDMA program:

(window displaying communication parameters)

Important! Before starting the program MDMA (Mobile Data Monitoring Application) It is necessary to close all “native” programs of the usb modem!!!

After launch, the program will display the signal level, airborne noise, and base station parameters. Here, our goal is to determine at what frequency the 3G & 4G LTE operator operates, by sorting them out. Pressing the button"Band Config" we will call the window in which we will perform simple actions:

1. Change the "Automatic" parameter to "Custom"
2. 3G check the box to start with UMTS 2100 Click "OK" and monitor the signal strength and network registration in the main window. If the operator's name appears in the field and a check mark appears next to "Registered", then your operator operates on the frequency UMTS 2100. If registration does not take place, return to the leading step and uncheck UMTS 2100 and install on UMTS 900.
   
3. If when selecting a parameter (for example, UMTS 900) the program generates an error, it means your modem does not work in this standard.
4. On 4G LTE network consistency and logic actions similar to 3G, except that they are all carried out in the right area (LTE Bands).

2.2 Analysis using a universal modem with Hilink interface:

Here, the actions are similar to the previous example; the range is also determined by enumerating frequencies.

Go to Settings -> Network settings, then select the standard (LTE, UMTS, etc.), set the “Manual” mode and start checking the ranges, checking the RSSI signal strength on the parameters page.

Determining the range in 3G networks:

Page displaying signal parameters

It should be noted that there are cases when the operator broadcasts the Internet directly totwo ranges at the same time. For example, in Chekhov M.O. Tele2 in 4G operates in parallel at 800 and 2600 MHz. The RSSI power varies, but the main frequency remains 800 MHz. If you want to provide greater speed and use both frequencies for reception, you should use a multi-standard antenna that supports LTE - A technology in 2 bands simultaneously.

Many people are interested in the dependence of signal level on speed. From our work experience it is clear that the speed decreases and stability disappears only at a very low signal level. And at medium and high levels, the speed of Internet access practically does not change and directly depends on the load of the base station. Many companies that install 3G Internet scam their clients out of money by offering to install a powerful antenna almost next to the base station, while promising higher speed and stability. In reality, this is just a scam for money. We are interested in a good reputation and installation integrity. Therefore, we will never offer you to install a powerful antenna when it is not necessary. Let's try to deal with different situations at different distances from the base station and decide what signal level is sufficient.

The signal level can be monitored in the MDMA program. Its number is shown in the RSSI column. Also, not only the signal level, but also the noise level is of great importance. This is also worth paying attention to. Now let's look at the level scale. The worst signal is -113 dB (virtually none) and the best is -51 dB (and higher). Note that the numbers have a minus sign. The closer it is to zero (the lower its value), the better.

The noise level can also be tracked in the same program in the SNR column, the second value after the decimal point. It ranges from 0 (better) to -20 and below (worse). With a value of -5...-3, the noise level is very low, and this has an extremely positive effect on speed and stability. The value -8...-12 is the average level, the speed will be noticeably lower. And below -12...-15 the noise is high, there is a lot of interference, the base station is heavily loaded, breaks are possible, etc.

It is very important to know the number of the base station (cell number) you have joined. One cell may be much less busy than another and vice versa. Accordingly, the speeds will also be different. Very often, a more distant cell turns out to be the best in terms of speed, despite the low signal strength. For example, a 3G modem without an external directional antenna connects to the first available cell, which is the best in signal strength, but not always the best in speed. A directional antenna helps connect the modem to the best cell in terms of speed. It also increases outgoing speed and improves stability.

Let's move on to the values ​​of the signal level and approximate speed (at a low noise level -5...-3):

-113...-110 dB. 0 sticks. The connection is unstable, the connection is constantly disconnected, the speed is around 1 Mbit/sec.

-109...-101 dB. 0 sticks. But the connection is still there and remains confident (with a directional antenna). Speed ​​1...3 Mbit/sec reception, 0.2...0.3 Mbit/sec transmission.

-100...-96 dB. 1 stick. Stable connection. Speed ​​3-5 Mbit/sec reception, 0.3...0.5 Mbit/sec transmission.

-95...-92 dB. 2 sticks. Speed ​​5-10 Mbit/sec reception, 0.7...1 Mbit/sec transmission.

-91...-87 dB. 3 sticks. Speed ​​10-15 Mbit/sec reception, 1-2 Mbit/sec transmission.

-86...-83 dB. 4 sticks. Speed ​​10-20 Mbit/sec reception, 2-3 Mbit/sec transmission.

-82...-50 dB. 5 sticks. Speed ​​10-25 Mbit/sec reception, 3-4 Mbit/sec transmission.

As you can see, with 2 “sticks” and higher, the incoming speed changes slightly. The signal level has a much greater effect on the outgoing speed. All results are approximate and obtained experimentally from real operating conditions. Those. If you manage to get a signal level higher than -95 dB, then you simply won’t notice any significant differences in speed. The speed very much depends on the load of the base station, and for 3G it is around 10 Mbit/sec. All results are given for 3G Internet. For 4G Internet, the signal level significantly affects the speed. And for its stable operation you need a signal of -90 dB or higher.

Also note that for some Megafon base stations, for stable 3G operation the signal level must be above -100 dB. There were cases when, when the signal level of Megafon was -102 dB, the outgoing speed was too low - around 0.02 Mbit/sec, and the connection was constantly disconnected. And for MTS, at a level of -107 dB, the incoming speed was 5-6 Mbit/sec, and the outgoing speed was 0.5 Mbit/sec. In practice, a lot depends on the load on the base station, as well as on the quality of the equipment at the base station.

How does distance from the base station affect signal strength? When removed from the base station by 5...10 km and with line of sight It is possible to get 3G Internet directly from a modem without an external antenna at a signal level above -100 dB. However, if there is no line of sight and the distance exceeds 10 km, then directional antennas will help you. If the signal level on your modem is -109 dB, then with a 14 dB directional antenna it will be equal to -109 + 14 = -95 dB, which is already quite enough for stable operation. And even if you live in the middle of nowhere and are 35 km away from the base station, you can still get high-speed Internet! Only in this case will you need a high mast (perhaps even higher than 10 meters) and a 0.9 m dish with an offset feed and honest gain in the region of 21...24 dB. We take on even the most difficult cases! A specialist will select the right set of equipment and antenna for you individually.

For preliminary signal measurement, we have a special quadcopter that allows you to quickly and efficiently measure signal levels without building mast structures and without calling a bucket truck (in difficult conditions). It is possible to rise to a height of up to 100 meters to assess the signal level, as well as to collect information about the terrain, etc. For this, a built-in video camera is used. This allows you to very accurately evaluate all the work on constructing mast structures and selecting a suitable antenna.

A prerequisite for its flight is a wind speed of no more than 2-3 m/s and the absence of rain or snowfall. If these conditions are absent, the signal is measured in the traditional way with the deployment of a temporary mast. The flight time is about 15 minutes - this time is quite enough to measure the signal and assess the terrain. Also, using a quadcopter allows you to throw a thin rope into hard-to-reach places. For example, on the roof of a house or on a tree. For subsequent pulling of a thick rope and securing it in order to perform high-altitude work on the installation of network equipment. This allows you to save a lot on work and speeds it up. Now you can install the Internet in absolutely any wilderness. Please note that using a quadcopter to measure the signal is absolutely free and is already included in the installation price!