Private branch mobile communication system and method

• US 6,571,108 B1
• Filed: 05/28/1999
• Issued: 05/27/2003
• Est. Priority Date: 05/29/1998
• Status: Expired due to Term

• Current Assignee: NEC Platforms, Ltd. (NEC Corporation)
• Original Assignee: NEC Corporation
• Inventors: Takai, Minako, Otsuka, Kiyokazu
• Primary Examiner(s): Vo, Nguyen T.
• Assistant Examiner(s): Orgad, Edan
• Application Number:
  US09/321,835
• Time in Patent Office: 1,460 Days
• Field of Search: 455/435, 455/463, 455/555, 455/426, 455/432, 455/436, 455/450, 455/462, 455/554, 455/464, 455/433, 379/198, 379/221.09, 379/225, 379/231, 379/232, 379/234
• US Class Current: 455/433
• CPC Class Codes: H04M 2203/1091 Fixed mobile conversion
• CPC Class Codes: H04M 3/42314 in private branch exchanges
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node
• CPC Class Codes: H04W 84/16 WPBX [Wireless Private Branch Exchange]

Abstract

The invention provides a private branch mobile communication apparatus and method which allows hand-over without interruption of communication and makes it possible to allow a service from a private branch exchange of a home node to be utilized as it is even if a radio terminal moves from the private branch exchange of the home node to another private branch exchange. A network common database, a local database and a memory section are stored in each of private branch exchanges. When a radio terminal forwards a position registration request to a radio base station belonging to a second private branch exchange other than the home node to the radio terminal, the second private branch exchange refers to the network common database to access the local database and the memory section of the private branch exchange of the home node, and then refers to the network common database to perform position registration into the private branch exchange of the home node and extract service data of an additional service to be performed by the private branch exchange which has received the position registration request other than the home node.

Claims

1. A private branch mobile communication system, comprising:

a distributed node switched network including a plurality of private branch exchanges each of which accommodates one or more radio base stations and has an identifiable node number provided thereto, and one or more radio terminals;

a common system ID which defines a range of use over said distributed node switched network being allocated to said radio terminals, private branch exchanges and radio base stations;

a network common database provided in each of said private branch exchanges and common for said radio terminals which have the system ID and the radio base stations, and a local database provided in each of said private branch exchanges for recording basic data of any of said radio terminals and said radio base stations into the private branch exchange so that the private branch exchange may serve as a home node to the radio terminal; and

means provided in each of said private branch exchanges for referring to said network common database to convert an ID from a radio terminal into a node number and a physical accommodation position provided by the private branch exchange of the home node to the radio terminal.

2. A private branch mobile communication system as claimed in claim 1, further comprising:

a subscriber control section provided in each of said private branch exchanges for controlling communication with any of said radio base stations which belongs to the private branch exchange and performing fetching and forwarding of various events;

a call control section provided in each of said private branch exchanges for discriminating which one of said private branch exchanges serves as a home node to that one of said radio terminals which has forwarded a position registration event by accessing said network common database of the private branch exchange itself and converting a unique ID of the radio terminal into a node number and a physical accommodation position;

a memory section provided in each of said private branch exchanges for storing position information of radio terminals and other related information; and

a control signal transfer section provided in each of said private branch exchanges for transferring a control signal for rewriting said memory section of the private branch exchange of the home node in response to an instruction of said call control section.

3. A private branch mobile communication system as claimed in claim 1, wherein said private branch mobile communication system forms a personal handyphone system.

4. A private branch mobile communication system as claimed in claim 2, wherein said private branch mobile communication system forms a personal handyphone system.

5. A private branch mobile communication system as claimed in claim 1, wherein said means for referring to said network common database comprises:

a receiving unit that receives information corresponding to a logical accommodation position of said radio terminal; and

a conversion section that refers to said network common database so as to convert said logical accommodation position to said node number and to a channel switch accommodation position.

6. A private branch mobile communication method, comprising the steps of:

forming a distributed node switched network from a plurality of private branch exchanges each of which accommodates one or more radio base stations and has an identifiable node number provided thereto, and one or more radio terminals;

allocating a common system ID which defines a range of use over said distributed node switched network to said radio terminals, private branch exchanges and radio base stations;

storing, into each of said private branch exchanges, a network common database common for the radio terminals which have the system ID and a local database for recording basic data of any of said radio terminals into the private branch exchange so that the private branch exchange may serve as a home node to the radio terminal and radio base stations;

determining, when any of said radio terminals which has the common system ID forwards a position registration request to one of said radio base stations which belongs to one of said private branch exchanges other than the home node to the radio terminal itself, by the private branch exchange to which the position registration request has been forwarded, an ID unique in the network of the radio terminal from said network common database and communicating, based on the ID unique in the network determined from the network common database and the node number, the position registration request of the radio terminal to the private branch exchange of the home node designated by the node number; and

updating, by the private branch exchange of the home node, the position registration information of the memory section regarding the radio terminal.

7. A private branch mobile communication method as claimed in claim 6, wherein, when the radio terminal performs a busy transfer request, data for busy transfer is read out from the memory section of the private exchange of the home node to the radio terminal, and a communication path is established between the radio terminal and an extension terminal of a destination of the transfer through the private branch exchanges.

8. A private branch mobile communication method, comprising the steps of:

forming a distributed node switched network from a plurality of private branch exchanges each of which accommodates one or more radio base stations, and one or more radio terminals;

allocating a common system ID which defines a range of use over said distributed node switched network to said radio terminals, private branch exchanges and radio base stations;

storing, into each of said private branch exchanges, a network common database common for the radio terminals which have the system ID and a local database for recording basic data of any of said radio terminals into the private branch exchange so that the private branch exchange may serve as a home node to the radio terminal; and

referring, when any of said radio terminals which has the common system ID performs a position registration event into one of said radio base stations which belongs to a second one of said private branch exchanges other than the home node to the radio terminal, by the second private branch exchange, to said network common database to access the memory section of the private branch exchange of the home node to perform position registration and reading out service data regarding the radio terminal stored in the private branch exchange individual data base of the home node, and then performing an additional service by the second private branch exchange.