Mobile Phone FTA voltage ragne

I remembered that it seems like the mobile phone proceed FTA should define
low voltage test value for testing. It depends on high voltage value to
multiply a ratio(<1) to get low voltage value. I'm not quite sure this rule.

Could someone tell me how to calculate low voltage value?
Or ETSI has another rule to get low voltage test value?
Thanks.

The phone manufacturer chooses the nominal voltage. ETSI is specifying the percent for min or max voltage for different battery types.
For example if nominal voltage is 3.6V and use a Lithium battery, the minimum voltage is 3.6*0.85=3.06V

Leclanché/lithium 0,85 * nominal nominal nominal