Poor 4G/LTE/3G/Edge reception on Galaxy S6 with Android 6.0.1

Poor 4G/LTE/3G/Edge reception on Galaxy S6 with Android 6.0.1 baseband G920AUCS4CPG1

For the past 3 months I've been experiencing extremely poor cellular/data reception both indoor and outdoor with my Galaxy S6 that I've had since October 2015 (11 months).  I did have good reception both indoor and outdoor before 3 months ago.  I think that the poor reception is causing my phone to use extra power to boost reception and decreasing my battery life.

My Phone:

Samsung Galaxy S6

Android 6.0.1

Baseband G920AUCS4CPG1

Please provide some me some guidance as to what could be causing the poor reception.  Is it a phone setting, does my phone need a reset, is there an outage where I work, live and drive?

Thanks!