tokens: ['Circuit', 'Switched', 'and', 'IP', 'Multimedia', 'Subsystem', 'IMS', 'Service', 'Continuity', 'for', 'Voice', 'Calls', 'This', 'term', 'identifies', 'a', 'specific', 'protocol', 'mechanism', 'that', 'enables', 'seamless', 'transition', 'and', 'continuity', 'of', 'voice', 'calls', 'between', 'different', 'network', 'types', 'such', 'as', 'circuitswitched', 'networks', 'and', 'IMS', 'It', 'ensures', 'that', 'users', 'do', 'not', 'experience', 'interruptions', 'during', 'handovers', 'maintaining', 'service', 'quality', 'in', 'heterogeneous', 'network', 'environments', '']