Mobile communication system having a control station which selects speech coding schemes for a mobile station

• US 5,991,642 A
• Filed: 09/10/1996
• Issued: 11/23/1999
• Est. Priority Date: 01/10/1995
• Status: Expired due to Term

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Mobile Communications Network Inc. (Nippon Telegraph and Telephone Corporation)
• Inventors: Yamamoto, Kouji, Katuta, Moritoshi, Nakaima, Noriya, Watanabe, Yasuyuki
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US08/712,053
• Time in Patent Office: 1,169 Days
• Field of Search: 455/550, 455/552.3, 455/422, 455/433, 455/435, 455/436, 455/464, 455/513, 455/517, 455/413, 455/414, 455/423, 455/450, 455/466, 455/445, 455/557, 455/60
• US Class Current: 455/560
• CPC Class Codes: H04W 28/24 Negotiating SLA [Service Level Agreement]; Negotiating QoS [Quality of Service]
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 88/181 Transcoding devices; Rate adaptation devices

Abstract

Communication is carried out on the basis of an optimum speech coding scheme that is matched to the speech coding schemes provided by the radio zones, and to the speech coding capabilities of the mobile stations. To achieve this, when a traffic channel is set up between a mobile station and a switch, a traffic channel selection condition that has been specified by the switch on the basis of the speech coding capabilities of the mobile station that made the SETUP request and of the mobile station to which the call is made, is stored in the control station. The control station grasps which speech coding scheme is currently being used in the radio zone which it controls. Moreover, by transferring the selection conditions specified by the switch and using these conditions as information required for channel setup by another control station, communication can be carried out using a high-priority speech coding scheme when handover occurs. This happens when channel selection takes place in another radio zone spanning control stations, or when a mobile station has moved to a radio zone in which a high-priority speech coding scheme can be used. As a result, traffic channels based on the optimum speech coding scheme can be changed over smoothly.

Claims

1. Mobile communication system comprising:

a plurality of mobile stations, at least two of said plurality of mobile stations being connectable to each other;

at least one switch which switches and connects transmission routes between two of said plurality of mobile stations respectively connected to two of said plurality of base stations; and

control stations which set and control the connection conditions of the base stations;

wherein at least one of said plurality of mobile stations can handle a single type of speech coding scheme, and at least one of said plurality of mobile stations can adaptively handle two or more different types of speech coding schemes;

the control stations include;

a table which temporarily stores, during the time interval from connection until release, conditions relating to the speech coding schemes of two connected mobile stations;

a means which independently selects the type of speech coding scheme on the basis of the content stored in said table without inquiry to or response from said at least one switch; and

a means which, when at least one of the two mobile stations has been connected to another base station, transfers the connection conditions to the control station pertaining to the other base station.

2. Mobile communication system as set forth in claim 1, wherein at least one of the plurality of base stations is capable of handling a single type of speech coding scheme, and at least one of the plurality of base stations is capable of adaptively handling two or more different types of speech coding schemes.

3. Mobile communication system as set forth in claim 1 or 2, wherein an order of priority is set in advance for the speech coding schemes which can be used by at least one of the plurality of base stations which is capable of adaptively handling two or more different types of speech coding schemes.

4. Mobile communication system as set forth in any of claims 1 to 2, further comprising:

a database in which is recorded which of the plurality of mobile stations can handle which speech coding schemes; and

said at least one switch includes a means which refers to said database when a connection is to be established by said switch and a means which transfers information recorded in said database to the control stations; and

the control stations have a means which records the transferred information in the aforementioned table.

5. Mobile communication system as set forth in any of claims 1 to 2, wherein the at least one switch includes a means which, when a connection is to be established by said switch, determines which speech coding schemes the two mobile stations to be connected can handle, this being done via the channels used for the connection control, and by means of information from those mobile stations.

6. Mobile communication system comprising:

a plurality of mobile stations, at least two of said plurality of mobile stations being connectable to each other;

at least one switch which switches and connects transmission routes between two of said plurality of mobile stations respectively connected to two of said plurality of base stations; and

control stations which set and control the connection conditions of the base stations;

wherein at least one of said plurality of mobile stations can handle a single type of speech coding scheme, and at least one of said plurality of mobile stations can adaptively handle two or more different types of speech coding schemes;

the control stations include;

a table which temporarily stores, during the time interval from connection until release, conditions relating to the speech coding schemes of two connected mobile stations;

a means which selects the type of speech coding scheme on the basis of the content stored in said table; and

a means which, when at least one of the two mobile stations has been connected to another base station, transfers the connection conditions to the control station pertaining to the other base station;

an order of priority is set in advance for the speech coding schemes which can be used by the at least one of the plurality of base stations which is capable of adaptively handling two or more different types of speech coding schemes; and

the speech coding scheme in use is changed in accordance with the order of priority when a mobile station capable of adaptively handling two or more different types of speech coding schemes has moved, during a call, from a radio zone of a base station capable of handling a single type of speech coding scheme, to a radio zone of a base station capable of adaptively handling two or more different types of speech coding schemes.

7. Mobile communication system comprising:

a plurality of mobile stations, at least two of said plurality of mobile stations being connectable to each other;

a plurality of base stations connected to said mobile stations by radio channels;

at least one switch which switches and connects transmission routes between two of said plurality of mobile stations respectively connected to two of said plurality of base stations; and

control stations which set and control the connection conditions of the base stations;

wherein at least one of said plurality of mobile stations handle a single type of speech coding scheme, and at least one said plurality of mobile stations can adaptively handle two or more different types of speech coding schemes;

the control stations include;

a table which temporarily stores, during the time interval from connection until release, conditions relating to the speech coding schemes of two connected mobile stations;

a means which selects the type of speech coding scheme on the basis of the content stored in said table; and

a means which, when at least one of the two mobile stations has been connected to another base station, transfers the connection conditions to the control stations pertaining to the other base station;

an order of priority is set in advance for the speech coding schemes which can be used by the at least one of the plurality of base stations capable of adaptively handling two or more different types of speech coding schemes; and

the speech coding scheme in use is set in accordance with the order of priority when said mobile station capable of adaptively handling two or more different types of speech coding schemes accesses a control channel of a base station capable of handling a single type speech coding scheme, and communicates by means of a traffic channel of a base station capable of adaptively handling two or more different types of speech coding schemes.

8. Mobile communication system comprising:

a plurality of mobile stations;

at least one base station connected to said mobile stations by radio channels;

at least one switch which, for a mobile station connected to said at least one base station, connects a transmission route to a called party belonging to an upper node; and

control stations which set and control the connection conditions of the base stations;

wherein, of the plurality of mobile stations, at least one of said plurality of mobile stations can adaptively handle two or more different types of speech coding schemes; and

the aforementioned control stations include;

a table which temporarily stores, over a time interval from connection until release, conditions relating to the speech coding schemes of two connected mobile stations;

a means which independently selects the type of speech coding scheme on the basis of the content stored in the table without inquiry to or response from said at least one switch; and

a means which, when at least one of two of said mobile stations has been connected to another base station, transfers the connection conditions to the control station pertaining to the other base station.

9. Mobile communication system comprising:

a plurality of mobile stations;

at least one base station connected to said mobile stations by radio channels;

at least one switch which, for a mobile station connected to said at least one base station, connects a transmission route to a called party belonging to a communication network connected to an upper node; and

control stations which set and control the connection conditions of the base stations;

wherein, of the plurality of mobile stations, at least one of said plurality of mobile stations are capable of handling a single type of speech coding scheme, and at least one of said plurality of mobile stations are capable of adaptively handling two or more different types of speech coding schemes;

the upper node has a means which converts the speech coding scheme to the speech coding scheme applied to the communication network; and

the control stations include;

a table which temporarily stores, over a time interval from connection until release, conditions relating to the speech coding schemes of two mobile stations which are connected;

a means which independently selects the type of speech coding scheme on the basis of the content stored in said table without inquiry to or response from said at least one switch; and

a means which when at least one of the two mobile stations has been connected to another base station, transfers the connection conditions to the control station pertaining to the other base station.

10. Mobile communication system comprising:

a plurality of mobile stations, at least two of said plurality of mobile stations being connectable to each other;

at least one switch which switches and connects transmission routes between two of said plurality of mobile stations respectively connected to two of said plurality of base stations; and

control stations which set and control the connection conditions of the base stations;

wherein at least one of said plurality of mobile stations can handle a single type of speech coding scheme, and at least one of said plurality of mobile stations an adaptively handle two or more different types of speech coding schemes;

the control stations include;

a table which temporarily stores, during the time interval from connection until release, conditions relating to the speech coding schemes of two connected mobile stations;

a means which selects the type of speech coding scheme on the basis of the content stored in said table; and

a means which, when at least one of the two mobile stations has been connected to another base station, transfers the connection conditions to the control station pertaining to the other base station;

at least one of the plurality of base stations is capable of handling a single type of speech coding scheme, and at least one of the plurality of base stations is capable of adaptively handling two or more different types of speech coding schemes;

an order of priority is set in advance for the speech coding schemes which can be used by the at least one of the plurality of base stations is capable of adaptively handling two or more different types of speech coding schemes; and

the speech coding scheme in use is changed in accordance with the order of priority when a mobile station capable of adaptively handling two or more different types of speech coding schemes has moved, during a call, from a radio zone of a base station capable of handling a single type of speech coding scheme, to a radio zone of a base station capable of adaptively handling two or more different types of speech coding schemes.

11. Mobile communication system comprising:

a plurality of mobile stations, at least two of said plurality of mobile stations being connectable to each other;

a plurality of base stations connected to said mobile stations by radio channels;

at least one switch which switches and connects transmission routes between two of said plurality of mobile stations respectively connected to two of said plurality of base stations; and

control stations which set and control the connection conditions of the base stations;

wherein at least one of said plurality of mobile stations handle a single type of speech coding scheme, and can adaptively handle two or more different types of speech coding schemes;

the control stations include;

a table which temporarily stores, during the time interval from connection until release, conditions relating to the speech coding schemes of two connected mobile stations;

a means which selects the type of speech coding scheme on the basis of the content stored in said table; and

a means which, when at least one of the two mobile stations has been connected to another base station, transfers the connection conditions to the control stations pertaining to the other base station;

at least one of the plurality of base stations is capable of handling a single type of speech coding scheme, and at least one of the plurality of base stations is capable of adaptively handling two or more different types of speech coding schemes;

an order of priority is set in advance for the speech coding schemes which can be used by the at least one of the plurality of base stations capable of adaptively handling two or more different types of speech coding schemes;

the speech coding scheme in use is set in accordance with the order of priority when mobile station capable of adaptively handling two or more different types of speech coding schemes accesses a control channel of a base station capable of handling a single type speech coding scheme, and communicates by means of a traffic channel of a base station capable of adaptively handling two or more different types of speech coding schemes.