Full resolution of mobile phone signal strength

1. DB
DB is a value that represents relative values. A pure ratio represents only the relative size relationship between two quantities, with no unit, when considering the number of DB whose power is larger or smaller than that of B,

The formula below is as follows: 10log (a power/B power). If the ratio of the two is used, 20log (a voltage/B voltage) is used ).)
[Example] If the power of a is twice the power of B, then 10lg (the power of a/B) = 10lg2 = dB. That is to say, the power of a is 3 dB higher than that of B.

If the power of a is half the power of B, the power of a is 3 dB lower than that of B.

2. DBM
DBM is a value indicating the absolute power value (or a ratio of 1 MW power as the benchmark). The formula is: 10log (power value/1 MW ).

[Example] if the power P is 1 MW, it is converted to dBm and then 0 dBm.
[Example] For 40 W power, the converted value in dBm unit should be:
10log (40 W/1 MW) = 10log (40000) = 10log4 + 10log10000 = 46dbm.
In short, DB is the ratio between two quantities, indicating the relative size between two quantities, while dBm indicates the absolute power size value. In dB and DBM computing, pay attention to the basic concepts,

When one DBM is used to subtract another dBm, the result is dB, for example, 30dbm-0dbm = 30db.

3. Cell phone signal strength Representation

Okay, soMobile phoneThe unit of the number shown on is dBm. When you look at it carefully, you will find that the value is negative. That is to say, the phone will display-67 (DBM), which indicates that the signal is very strong.

Here is a small knowledge:

China Mobile's specifications stipulate that when the mobile phone reception level is greater than or equal to (city-90dbm; Country-94dbm), the coverage requirements are met, that is, the wireless signal strength here meets the coverage requirements.

-67dbm is more than 20 DBS better than-90dbm signal, so it will have a much better voice quality in the call success rate and call process (of course, Edge/GPRSInternet accessSpeed)

Therefore, the larger the value, the better the signal, because it is a negative value, and it is always a negative value in your hands, if you feel

If you are interested in antennas with wireless base stations nearby, you can try to bring your mobile phone as close as possible to the antenna panel, so the value will grow bigger and bigger,

So it may be very close to 0 (0 cannot be reached, here the 0This does not mean that the phone has no signal .)

When selecting the engineering mode in the signal strength meter, a lot of parameters are displayed. You only need to check that bcchev (control channel level value) is the signal strength value of the mobile phone, in dBm, how big the signal your phone can normally answer it, BCCHLev-C1, C1 also has a display value, such as: bcchlev(-63), C1 (34 ), it indicates that your phone will not quit when the signal is greater than-97dbm.

Next, we can see how much transmission power a mobile phone needs. According to the GSM protocol, the transmission power of mobile phones can be controlled by base stations. The base station uses the downstream sacch channel to issue commands to control the transmit power level of the mobile phone,

2 dB for each power level;

The maximum transmit power level of the GSM 2000 mobile phone is 5 (2 W = mW, 33dbm), and the minimum transmit power level is 19 (3 MW, 5dbm ),

The maximum transmit power level of the DCS1800 mobile phone is0 (1 W, 30dbm), minimum transmit power level is 15 (1 MW, 0dbm ).

When the mobile phone is far away from the base station or in the wireless shadow area, the base station can command the mobile phone to send a large power until 33dbm (GSM900 ),

To overcome the signal loss caused by long-distance transmission or building occlusion.

The txpower in the intensity meter is the transmit power of the mobile phone. When you call the phone, you can see the transmit power of your mobile phone. That is, the larger the value, the more power-saving the radiation, the smaller the radiation, and the value at 5,

Your phone consumes a lot of powerBatteryIt may take less than one day for others to hear your voice during a call. Your mobile phone may suddenly fail to receive a signal, so that you can call a complaint to allow the operator to overwrite the signal,

Make your mobile phone signal better and reduce radiation.

The above words have only one core meaning. Don't be fooled by your phone signal !!! It is defined by mobile phone manufacturers. To be professional, you can view the signal strength dBm directly.
AndroidSystemCheck the signal strengthSet-About mobile phone-in the network.

There is a gap between indoor and outdoor signal strength. Generally, the outdoor signal is better than the indoor signal.
Now let's look at the so-called dBm. The value range is-xx ~ Between 0. The larger the number, the higher the signal strength.

-50dbm ~ Within the 0dbm range, congratulations! Your signal is very good. You can stand next to the base station, right?
-90dbm ~ -60dbm. Congratulations, you will not be able to make a phone call. If you cannot, contact the carrier. That's their problem.

GIn the room, the signal strength of the DS table is-67dbm and 23asu. In the phone handshake,-75dbm, 19asu. Adjust the positions to see at least-83dbm and 15asu.

What level does this belong? In short, the signal is very good. Not looking outside, but definitely higher than this,
For other mobile phones, you can visit the Internet by yourself. Most of the DBM values of Ds are in the same grade. Some posts show off that they are larger than-50dbm because they are on the edge of the base station. The normal range is-90dbm ~ -60dbm.

 

Reprinted: http://bbs.imobile.com.cn/thread-tid-9627189.html