Hello QuangCa,
I hope all is great with you. Thank you for using the NXP communities.
In this case, I do recommend reviewing the Starter Package for NTM88 and MKW01 as reference for our design. You can download it from your Software tab.
Within the Demo_project_NTM88 the RSSI value is given by the MKW01.
I hope this information helps.
Regards,
David
