Are mobile phone signal booster receivers really useful?

A mobile phone booster can enhance the signal of a mobile phone.
The principle of use is very simple. For example, the light second brand mobile phone signal amplifier uses a booster to introduce a good outdoor signal to the host, and spreads it to every corner of the room through the indoor ceiling to strengthen the mobile phone signal.
The signal strengthening receiver is a mobile phone signal automatic optimization tool. Through the analysis and selection of communication base stations, actively switch high-quality idle base stations, and change the default passive switching mode, so as to achieve the effect of mobile terminal signal enhancement. Tests have shown that the call effect can be significantly improved by turning on the signal booster.