tokens: ['Figure', '', 'depicts', 'the', 'MMTel', 'offline', 'charging', 'architecture', 'Figure', '', 'MMTel', 'offline', 'charging', 'architecture', 'This', 'MMtel', 'offline', 'charging', 'architecture', 'is', 'based', 'on', 'the', 'IMS', 'offline', 'charging', 'architecture', 'described', 'in', 'TS', '', '', 'with', 'service', 'CTFs', 'supporting', 'MMtel', 'specific', 'service', 'charging', 'interfacing', 'the', 'CDF', 'through', 'the', 'Rf', 'reference', 'point', 'The', 'CTFs', 'considered', 'in', 'the', 'MMTel', 'offline', 'charging', 'architecture', 'reside', 'in', 'the', 'Application', 'level', 'network', 'functionality', 'providing', 'MMTel', 'service', 'and', 'supplementary', 'services', 'The', 'CTFs', 'related', 'to', 'charging', 'for', 'the', 'IMS', 'basic', 'capabilities', 'supporting', 'MMTel', 'service', 'are', 'described', 'in', 'TS', '', '', 'and', 'reside', 'in', 'the', 'set', 'of', 'IMS', 'Nodes', 'SCSCF', 'MRFC', 'reflected', 'in', 'IMS', 'offline', 'architecture']