Shulou(Shulou.com)11/24 Report--

People often encounter weak cell phone signals.

Generally speaking, we will judge the current signal strength by the signal identification in the upper right corner of the phone.

But in fact, this method of judgment is too crude. Not only the accuracy is not high, but also may not be accurate.

As a veteran communication driver, today, Xiao Zaojun will introduce you some more professional methods for judging mobile phone signals. At the same time, it also gives you some basic knowledge about mobile phone signals.

First of all, I would like to tell you some of the ways to check the signal that comes with your phone. You can view the signal strength without the help of a third-party App.

█ iPhone View opens the iPhone dialing interface, type * 3001 "12345" * in the dial button, and then click the dial button to view the phone's signal-related data.

Be careful! The menu content here will be different for different versions of the phone. And, to wait, it will take some time for the system to query the data. After a while, more menus will come out.

Click [NR Rach Attempt] under [5G] to view the value of 5G signal strength (cell_rsrp, the following figure is-98):

Click [Rach Attempt] under [4G] to view the value of 4G signal strength (rsrp, the following figure is-87):

The unit of these values is dBm. DBm is calculated by logarithm, so it is usually negative. For a specific introduction to dBm, see here: dB, dBm, dBw, dBi. What's the difference? )

Note that the smaller the absolute value of dBm, the better the signal quality.

The comparison reference is as follows:

In [Serving Cell Info] of [RAT], you can also see the following information:

Jujube Jun simply gives you a few more important parameters.

PLMN: the operator's public land mobile network code. Every operator is different. PLMN consists of MCC (mobile country code, 3 digits) and MNC (mobile network code, 2-3 digits). 46011 is the 4G / 5G of China Telecom.

KCTCellMonitorBWPSupport: type of support for adaptive carrier bandwidth.

Band Info: band number, 78 on the chart refers to N78.

5G band number (Sub-6 band) Bandwidth: frequency bandwidth, 20MHz on the chart.

CellID: cell number.

Radio Access: wireless access type. NR is 5G. LTE is 4G.

NRARFCN:5G frequency dot number. The band range 0-100GHz marks a total of 3279165 grids. These grids are numbered from 0 to 3279165. Each number represents an absolute frequency domain location, and these numbers are called NR-ARFCN. This frequency number has its own calculation formula, which can be found on the Internet.

PCI:Physical Cell Identifier, physical community identification. A wireless signal used to distinguish between different cells.

TAC:Tracking Area Code, tracking area code. It is assigned by the operator, which mainly plays the role of unique identification of mobile user location.

The way █ Android phones are viewed, then look at Android.

Different brands of Android phones have different ways to check signal strength.

Let's take Xiaomi (MIUI 14) as an example, open the phone's [Settings]-[my device]-[all parameters and Information]-[status Information]-[SIM Card status (SIM Card slot 1)] (or slot 2), and you can see the real-time signal strength. As shown below:

This interface Xiaomi mobile phone system does not allow screenshots, I can only take pictures. The signal strength is-93dBm. Asu is Arbitrary Strength Unit, the unit of subjective strength, which can be regarded as the relative value of signal strength.

Asu can be obtained through dBm. The calculation formula is as follows:

LTE and 5G:asu=dBm+140

WCDMA and GSM: asu= (dBm+113) / 2

The network type is 5G_SA, which means 5G independent networking (Standalone). For SA and NSA, you can see here: what exactly do 5G NSA and SA mean?

The viewing method of the third-party App of █ is good. The above is the viewing method that comes with the mobile phone. As you can see, the information you view is still relatively simple.

What should I do if I want to see more detailed information? That requires the help of third-party App software.

This kind of software is more, I am more commonly used is Cellular-Z. The app store that comes with the phone should be able to download it. It is not recommended that everyone go online to find the installation package, it is easy to be poisoned.

After Cellular-Z is installed, start it and go to the main interface:

As you can see, it is quite functional-in addition to the signal status of the phone's two card slots, it can also see Wi-Fi and GNSS (satellite positioning), as well as the complete information of the phone itself.

The various parameters of the card slot information have just been interpreted by Xiao Zaojun, so I will not repeat them here. There is a NR-FREQ, which is the current specific 5G frequency of the phone.

The signal strength, which shows the numerical value, also shows the dynamic diagram. As mentioned earlier, the lower the absolute value of the value, the better the signal.

The signal has several parameters, let's talk about them separately. (more professional, you can skip it if you don't want to see it)

RSRP:Reference Signal Receiving Power, reference signal reception power.

What we are mainly looking at is this parameter. It is the average of the signal power received on all RE (resource elements) that carry the reference signal within a Symbol (symbol). The range is between-44 and-140, the larger the better.

RSRQ:Reference Signal Receiving Quality, reference signal reception quality.

It is the ratio of RSRP to RSSI, ranging from-3 to-19.5, the larger the better. It mainly sorts different LTE candidate cells according to the signal quality. This measurement is used as an input to handover and cell reselection decisions.

RSSI:Received Signal Strength Indication, the received signal strength indication.

It attenuates with the increase of distance, usually a negative value, and the closer the value is to zero, the higher the signal strength. The RSSI remains too low, indicating that the uplink signal received by the base station is too weak, which may lead to demodulation failure. RSSI continues to be too high, indicating that the received uplink signal is too strong, the interference between each other is too large, but also affect the signal demodulation.

SINR:Signal to Interference plus Noise Ratio, signal to interference plus noise ratio.

It represents the ratio of the strength of the received useful signal to the strength of the received interference signal (noise and interference).

█ about Wi-Fi, by the way, Wi-Fi.

Wi-Fi is divided into 2.4GHz band and 5GHz band (and 6GHz band, which is not available in China at present). The channels in both bands include the following:

2.4GHz band

Attention in the 5GHz band, the 2.4GHz band is very crowded. Mobile phones should try not to use the 2.4G band, but should use the 5GHz band. Smart home products generally support only 2.4G band, which can make do with it.

With this tool, you can see which channel is free at home.

Then, on your own Wi-Fi router, you can set up this free channel (for example, the 48 channel in the figure above, which belongs to the 5GHz band). The Wi-Fi signaling experience will be much better.

█, let's talk about speed measurement.

Sometimes, the high signal strength does not necessarily mean that the network is fast. When the number of user access is too large, or the transmission resources of the base station are congested, it may also occur that "the signal is full, but the network speed is very slow".

For speed measurement, it is generally with the help of a third-party App, such as Speedtest.

Turn on position authorization so that you can select a closer speed measurement point, and then start the speed measurement.

In general, the 5G speed measurement will not exceed the 1000Mbps. The speed of a few hundred bps is already excellent. Dozens of Mbps, there is no problem watching video and chatting. If you only have a few Mbps, the online experience is a little tough.

█ about complaints if there is often a problem of poor network signal quality, you can call the operator customer service phone to complain. If the operator is slow to solve the problem, you can also call the Ministry of Industry and Information Technology (12321) to lodge a complaint.

In the vicinity of some mysterious units, or near the R & D buildings of equipment vendors such as ZTE Huawei, mobile phone signal problems often occur, possibly because of interference. This can also be complained about.

Remind everyone again, the base station signal is poor, the individual, property or company is powerless, can only let the operator solve. Except for operators, no one or unit is allowed to build their own public network communication base stations.

If the base station signal is poor, you can deploy Wi-Fi to access the Internet, but Wi-Fi does not allow you to make phone calls or send text messages (except for Internet phone services such as Wechat video calls). Therefore, there will still be other people calling you, indicating that "the number you dialed cannot be connected".

All right, that's today's popular science. Does everyone understand?

This article comes from the official account of Wechat: fresh Jujube classroom (ID:xzclasscom), author: Xiaozaojun

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