What does the dbm of mobile phone signal mean?

unit of power and p (watt) conversion formula:

(1*P)DBm=(1*P)dB-3dB (P: watt)

First, DB is a pure counting unit: for power, dB = 1*lg(A/B). For voltage or current, the meaning of dB = 2*lg(A/B).dB is actually very simple, that is, a very large number (followed by a long string of zeros) or a very small number (preceded by a long string of zeros) is expressed briefly. For example:

x = 1 (how many? )

1lgx = 15db

x = .1

1lgx =-15db

DBM defines miliwatt. dBm=1lg1mw；

dBw defines watt. dBw = 1lg1 W = 1lg1 mw = 3 dBm。

by default, db always defines the unit of power, which is 1lg. Of course, in some cases, signal intensity can be used to describe work and power, and then 2lg is used. This is true in both control field and signal processing field. For example, sometimes you can see the expression of dBmV.