Mobile Communications Network -1.Basic Technology of Portable and Automobile Telephones

For a portable telephone to call a fixed telephone, the local switch first performs call origination reception. A call origination information query is then conducted between the local switching station and the service control station, followed by a security check and channel setting between the local switching station and the portable telephone. From the local switching station, the call termination signals are transmitted through a gateway switching station and POI to other networks, for example, NTT's fixed telephone network. If the fixed telephone network sends a connect signal, the call is started.

If a fixed telephone calls a portable telephone, the signals first reach a gateway switching station via POI from NTT's fixed telephone network, and the connection is initiated. Subsequently, the gateway switching station sends call termination signals to the local switching station after querying the service connection station for call termination information. The local switch transmits a signal to the portable telephone through the radio base station and, if there is an answer, the security check and channel setting are conducted. Once a connect signal is returned from the portable telephone, the call can be initiated.

If a portable telephone calls another portable, the procedures up to initiating the security check and channel setting are the same as those for calls to a fixed telephone. After these steps, the local switching station queries the service control station for call termination information, and then sends call termination signals to the called party's local switch through the gateway switching station. If there is an answer from the called party's portable telephone, the security check and channel setting are then carried out, and the call can be initiated in response to a connect signal from the called party's portable telephone.

(1) Outgoing Call Acceptance

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(2) Query on Outgoing Call Information

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(3) Security Check

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(4) Channel Set-Up

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(5) Call Accepted by NTT Network

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(6) Response and Start of Communications

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Connection of Outgoing Calls from a Mobile Station

noticeCreated 1999/03

noticeUpdated 2004/03

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