Processes for the epoxidation of ethylene are provided in which, following start-up, an epoxidation catalyst is contacted with a feed comprising ethylene, oxygen, carbon dioxide in an amount below 2. A metal oxide is evaporated at predetermined temperature conditions, and is swept towards a reacting zone, to which first and second gas phase reacting agents are concurrently swept. The GSM1\xd7 system is built using standard CDMA as its air interface and an unmodified CDMA RAN with a standard IOS interface to the MSN.