Personal Handy-phone System signalling protocol architecture: study on internetwork interface for PHS roaming

Mobile telecommunication systems provide roaming service which allows calls to be made using different network operators in different geographic areas. This paper presents a study on internetwork signalling protocol architecture for PHS roaming. It's based on the distributed functional plane model for IN CS1 defined by ITU-T SG 11. The network capabilities, internetwork procedures and protocol structure for the roaming service are discussed, and the data model is proposed.