Power limit for signal receptiion

[Spiders]

Hi

For some LTE cellphon, I would like to amplify the received signal. I would like to know if there is a powerlimit on the receive path that I shouldn't exceed?
For exemple;
-is it risky for the cellphone to add anLNA with a gain up to 20 dB for exemple on the receiving path? could it damage the cellphone ?
-If there is receive power limit which we shouldn't exceed to avoid device damage, how or where could I identify it? What is the term used for that limit or to look for ?

Regards,

 

[KlausST]

Hi,

Is there an improvement when you amplify the received signal only?
Usually you need to amplify the transmitted signal, too, because cellular phone communication is always in both directions.
How did you decide to achieve this?

Klaus

 

[FvM]

You can be pretty sure that the sensitivity of your mobile phone is already noise limited, using a state-of-the-art LNA in the RX path. So it's just useless to add more gain.

Secondly I don't believe that modifying a recent mobile phone is an actual option for you.

 

[Spiders]

You can be pretty sure that the sensitivity of your mobile phone is already noise limited, using a state-of-the-art LNA in the RX path. So it's just useless to add more gain.

Secondly I don't believe that modifying a recent mobile phone is an actual option for you.

Why should I be pretty sure ?
What is the term used for that limit and how could I find it in a datasheet?

I didn't say that I am doing this on a "recent" mobile phone

 

[betwixt]

Spiders, the issue is that unless you can break the signal path in the phone between the antenna and PIN switch it would be of no benefit to you anyway. All digital phones adapt their transmit power according to a command sent from the base station. If the base station receives a weak signal it increases the phones TX power and if the signal gets stronger it tells it to reduce. The same happens in the opposite direction. If you make the phone more sensitive you unbalance the system and one or the other direction will fail prematurely.

As for actual received signal level, it is usually only a few uV so it would take massive voltage gain to do any damage. Bear in mind there is a powerful transmitter in the phone and also that it has to be capable of operation only metres away from a cell mast so the input stage is designed to withstand strong signals.

Brian.