  The muon spectrometer of the CMS (Compact Muon Solenoid) experiment at the
Large Hadron Collider (LHC) is equipped with a redundant system made of
Resistive Plate Chambers and Drift Tube in barrel and RPC and Cathode Strip
Chamber in endcap region. In this paper, the operations and performance of the
RPC system during the first three years of LHC activity will be reported. The
stability of RPC performance, such as efficiency, cluster size and noise, will
be reported. Finally, the radiation background levels on the RPC system have
been measured as a function of the LHC luminosity. Extrapolations to the LHC
and High Luminosity LHC conditions are also discussed.
