COMS ERROR AND SIMILAR CALL SIGNS LEADS TO PLTDEV.

Narrative

THIS INCIDENT OCCURRED; I BELIEVE; AS A RESULT OF AN OVERLOADED AND OVERWORKED ATC SYS. THE ENTIRE FLT WAS CONSTANT HDG CHANGES; RADIALS TO INTERCEPT ALT AND AIRSPD CHANGES. FOR EXAMPLE; SHORTLY AFTER HDOF TO ZOB WE THOUGHT WE HEARD 'CLB TO FL270.' BTWN BEING STEPPED ON AND THE CTLR WORKING MORE THAN 1 FREQ; IT TOOK 4 ATTEMPTS ON OUR PART TO VERIFY OUR CLRNC. WE WERE AT OUR CRUISE ALT OF FL310 ON ZID AND GIVEN A PLT'S DISCRETION TO FL240. I CAN'T RECALL FOR SURE BUT I THINK WE WERE HANDED OFF TO ANOTHER CTLR AND CLRED TO 13000 FT; AND WE STARTED DSCNT. IT WOULD BE IMPOSSIBLE TO RECALL TIMES; HDGS; AIRSPD CHANGES; ETC WITH ANY DEG OF ACCURACY. DURING THIS TIME WE COMMENTED AMONG OURSELVES THERE DIDN'T SEEM TO BE ANY KIND OF FLOW BEING ESTABLISHED. WE COULD VISUALLY SEE SEVERAL ACFT; SEEMINGLY ALL HEADED IN DIFFERENT DIRECTIONS AT VARIOUS ALTS. AT SOME POINT WE HEARD 'MAINTAIN YOUR ALT.' WE LEVELED OFF AND MAINTAINED FL195 AND INFORMED THE CTLR. AT NO TIME WERE WE GIVEN TA'S. IN FACT; NOTHING WAS SAID UNTIL APPROX 5 HRS LATER WHEN A COMPANY SUPVR APCHED ME CONCERNING THIS INCIDENT. COULD WE HAVE ACCEPTED A CLRNC INTENDED FOR SOMEONE ELSE? POSSIBLY. IF SO; THE CTLR DIDN'T CATCH THE ERROR AND THIS HAS HAPPENED MANY TIMES INBOUND TO SDF. DID WE READ A CLRNC BACK WRONG? POSSIBLY. WE WEREN'T CORRECTED. COULD THE CTLR HAVE THOUGHT ONE THING AND SAID ANOTHER OR BEEN THINKING ONE FLT NUMBER AND ISSUED A CLRNC TO ANOTHER? I DON'T KNOW THE ANSWER. WHAT I DO KNOW IS THE CONSTANT STREAM OF ALT; AIRSPD AND HDG CHANGES BEING GIVEN EVERY NIGHT INBOUND TO LOUISVILLE. CONTRIBUTING FACTOR: MANY COMPANY FLT NUMBERS ARE VERY SIMILAR. A COMPREHENSIVE AND REALISTIC REVIEW OF SDF ARR PROCS NEEDS TO BE CONDUCTED. TO INCLUDE ZID; SDF ARR AND COMPANY POSSIBLY ADJOINING CTRS TOO. IF WE DID APCH ANOTHER ACFT; WHICH I AM NOT QUESTIONING; IT'S ONLY A MATTER OF TIME BEFORE IT HAPPENS AGAIN.