Medium Large Transport
Flight Crew Air Transport Pilot (ATP)
Distraction; Confusion; Communication Breakdown; Situational Awareness
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway
Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance
Procedure; Human Factors
When approaching spot 25 (old North line) the north ramp told us to request Mike Charlie as his area was busy.  The First Officer thought he was contacting ground to get the clearance (in hindsight; I think he had re-contacted inbound ramp).  The wording that was used lead both of us to believe we were cleared Mike Charlie.  It sounded like a clearance versus instructions to contact ground.  I didn't look down at the frequency but thought that we were cleared Mike Charlie to the North ramp.  So I proceeded Mike Charlie.The tower had me call on the phone and informed me.I didn't check the frequency; I just listened to the words and wording of the directions.I talked it over with the First Officer (FO) and he believes he did contact ground for the Mike Charlie clearance.Always check the frequency being talked on before following the directions given.
Upon landing on 36L took taxi way N and held short of 36C.  Switched to 126.4 to monitor for clearance to cross and acknowledged clearance to cross with call sign.  Apparently it was for another aircraft with similar call sign but ATC also cleared us as well before we passed the hold short line.  Acknowledged again for second time we were cleared to cross. On taxi in at spot 25N we were holding in sequence to go to our gate when aircraft in front of us got clearance to proceed down taxi way M then C.  We asked if we could follow the traffic (on 121.9) and understood that we could.  Then proceeded down MC to enter at C-10. Upon proceeding to gate we were asked to contact tower by phone.  He stated that we did not receive clearance to proceed down taxiway MC.  We stated we thought we did otherwise we would not have proceeded. On taxi in approaching we were told to contact the tower by phone.I believe with the large volume of traffic on the ground it becomes easy to misidentify a call sign especially when they are similar.  The radio frequency is more than crowded during push times. Limit the number of departures and arrivals in CLT.
Pilots report of landing at CLT and then having confusion about a similar call sign. An aircraft with a similar call sign is given a clearance and then their aircraft is given clearance. The pilots thought they had clearance to use taxiway MC but ATC said they did not.