Call routing in a telecommunication system

• US 20020196781A1
• Filed: 05/23/2002
• Published: 12/26/2002
• Est. Priority Date: 12/02/1999
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Salovuori, Heikki
• Granted Patent: US 7,606,261 B2
• Time in Patent Office: Days
• US Class Current: 370/352
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services
• CPC Class Codes: H04W 88/16 Gateway arrangements
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A method of routing calls in a telecommunication system comprising a mobile services switching center (MSC) and a base station connected thereto, and mobile stations wherefrom a telecommunication connection is established by using a first predetermined protocol on a radio connection. The telecommunication system further comprises a packet data network, a server communicating with the MSC and the packet data network, wherefrom a telecommunication connection is established through the packet data network and the server to the MSC. In the server, messages according to the first protocol supplied from the MSC are as such arranged into data packets of data network protocol to be forwarded through the packet data network to the terminal. The terminal transmits and receives the messages according to the first protocol arranged as such into the data packets of the packet data network protocol and emulates a mobile station using the first protocol.

Claims

1. A method of routing calls in a telecommunication system comprising

a mobile communication system comprising at least one mobile services switching centre and at least one base station connected thereto, and mobile stations wherefrom a telecommunication connection is established to the mobile services switching centre through the base station by using a first predetermined telecommunication protocol on a radio connection,

a packet data network wherein data to be transmitted is transmitted in data packets, according to a protocol specified for the packet data network,

a server communicating with the mobile services switching centre and said packet data network, the server being configured to arrange messages according to the first telecommunication protocol arranged as such into data packets according to said packet data network protocol and supplied from the mobile communication system to be forwarded through said packet data network to the terminal, the server being further configured to decompress messages according to the first telecommunication protocol arranged as such in the data packets according to said packet data network protocol and supplied from the terminal through the packet data network to be forwarded to the mobile communication system, and

at least one terminal, which is arranged to support said packet data network protocol and from which terminal a telecommunication connection is established through the packet data network and the server to the mobile switching centre, the method comprising

establishing a telecommunication connection from said terminal to said packet data network by using a second predetermined telecommunication protocol, through which telecommunication connection the data packets according to said protocol specified for the packet data network can be transmitted,

transmitting and receiving by said terminal the messages according to the first telecommunication protocol arranged as such into the data packets according to said packet data network protocol, and

emulating a mobile station using said first telecommunication protocol by the terminal.

2. A method as claimed in claim 1, further comprising

establishing from said server a data transmission connection between the mobile services switching centre and said packet data network, and authenticating, by said server, said terminal in response to a connection setup request transmitted by the mobile station or the terminal.

3. A method as claimed in claim 1, wherein

said protocol specified for the packet data network is an IP protocol, whereby information on IP addresses of the terminals is maintained by said server, and data transmission directed to the terminals is routed according to said IP addresses.

4. A method as claimed in claim 1, further comprising

connecting said terminal to a group call according to the mobile communication system using said first telecommunication protocol, such as a TETRA protocol.

5. A method as claimed in claim 4, further comprising

activating, from said server, said terminal into a group by establishing a connection to the terminal, and transmitting necessary group call numbers to the terminal in response to an activation request issued by the mobile communication system or the terminal.

6. A method as claimed in claim 5, further comprising

connecting the terminal to the group call by transmitting a call setup message, such as H.323 call setup signalling, from said server to an IP address of the terminal.

7. A method as claimed in claim 5, further comprising

initiating group call setup from said terminal by transmitting a call setup message to an IP address of the server.

8. A method as claimed in claim 6, further comprising

transmitting a request for a speech item in the group call as fast signalling, such as a short message or a WAP message, from said terminal to said server in response to a press of a PTT button specified in the terminal.

9. A method as claimed in claim 6, further comprising

connecting to the group call several terminals which have established a telecommunication connection from said server to said packet data network by using a second predetermined telecommunication protocol.

10. A method as claimed in claim 4, further comprising

connecting said terminal to several at least partly simultaneous group calls.

11. A telecommunication system for routing calls, the system comprising

a mobile communication system comprising at least one mobile services switching centre and at least one base station connected thereto, and mobile stations arranged to establish a telecommunication connection to the mobile services switching centre through the base station by using a first predetermined telecommunication protocol on a radio connection,

a packet data network wherein data to be transmitted is arranged to be transmitted in data packets, according to a protocol specified for the packet data network,

a server communicating with the mobile services switching centre and said packet data network, said server being configured to arrange messages according to the first telecommunication protocol supplied from the mobile services switching centre as such into data packets according to said packet data network protocol to be forwarded through said packet data network, the server being further configured to decompress messages according to the first telecommunication protocol arranged as such in the data packets according to said packet data network protocol and supplied from the packet data network to be forwarded to the mobile switching centre, and

at least one terminal arranged to establish a telecommunication connection through the packet data network and the server to the mobile switching centre,

said terminal is arranged to establish a telecommunication connection to said packet data network by using a second predetermined telecommunication protocol, through which telecommunication connection the data packets according to said protocol specified for the packet data network can be transmitted,

said terminal is arranged to transmit and receive the messages according to the first telecommunication protocol arranged as such into the data packets according to said packet data network protocol, and

the terminal using said second telecommunication protocol is arranged to emulate a mobile station using said first telecommunication protocol.

12. A telecommunication system as claimed in claim 11, wherein

said server is arranged to establish a data transmission connection between the mobile services switching centre and said packet data network, and to authenticate said terminal in response to a connection setup request transmitted by the mobile station or the terminal.

13. A telecommunication system as claimed in claim 11, wherein

said protocol specified for the packet data network is an IP protocol, and said server is arranged to maintain information on IP addresses of the terminals and route data transmission directed to the terminals according to said IP addresses.

14. A telecommunication system as claimed in claim 13, wherein

the maintenance of said IP addresses is arranged to be carried out according to a protocol supporting the mobility of the IP addresses, such as an AIP or Mobile IP protocol.

15. A telecommunication system as claimed in claim 11, wherein

said terminal is arranged to be connected to a group call according to the mobile communication system using said first telecommunication protocol.

16. A telecommunication system as claimed in claim 15, wherein

said server is arranged to activate said terminal into a group by establishing a connection to the terminal and to transmit necessary group call numbers to the terminal in response to an activation request issued by the mobile communication system or the terminal.

17. A telecommunication system as claimed in claim 16, wherein

said terminal is arranged to transmit a request for a speech item in the group call as fast signalling, such as a short message or a WAP message, to said server in response to a press of a PTT button specified in the terminal connected to the group call.

18. A telecommunication system as claimed in claim 17, wherein

said server is arranged to connect to the group call several terminals which have established a telecommunication connection to said packet data network by using a second predetermined telecommunication protocol.

19. A telecommunication system as claimed in claim 11, wherein

said mobile communication system is a TETRA system and said terminal is one of the following:

a GSM/GPRS terminal

a UMTS terminal

a workstation of a local area network

a terminal according to a wireless network, such as an IEEE 802.11

a terminal of a satellite telephone system

a combination thereof.

20. A terminal of a telecommunication system, the terminal being arranged to establish a telecommunication connection through a packet data network and a server to a mobile communication system arranged to utilize a first predetermined telecommunication protocol, data transmitted in the packet data network being arranged to be transmitted in data packets, according to a protocol specified for the packet data network, the terminal being arranged to transmit and receive messages according to the first telecommunication protocol arranged as such into data packets according to said packet data network protocol, and arranged to establish a telecommunication connection to said packet data network by using a second predetermined telecommunication protocol, through which telecommunication connection the data packets according to said protocol specified for the packet data network can be transmitted, and the terminal is arranged to emulate a mobile station using the first telecommunication protocol.

21. A terminal as claimed in claim 20, wherein

the terminal is arranged to be connected to a group call according to the mobile communication system using said first telecommunication protocol.

22. A terminal as claimed in claim 21, wherein

the terminal is arranged to issue an activation request to said server for participating in the group call and to receive necessary group call numbers.

23. A terminal as claimed in claim 20, wherein

the terminal is arranged to be connected to several at least partly simultaneous group calls.

24. A terminal as claimed in claim 20, wherein

the terminal is arranged to emulate a terminal of a TETRA system and the terminal is one of the following:

a GSM/GPRS terminal

a UMTS terminal

a workstation of a local area network

a terminal according to a wireless network, such as an IEEE 802.11

a terminal of a satellite telephone system

a combination thereof.

25. A terminal as claimed in claim 20, wherein the terminal comprises

signal generating means for performing call control signalling through said packet data network to said server,

means for forming and decompressing speech frames and signalling messages according to said first predetermined telecommunication protocol in data packets according to said protocol specified for the packet data network, means for decrypting the encryption in the received frames according to the first predetermined telecommunication protocol, and for encrypting the frames to be transmitted according to the first predetermined telecommunication protocol,

means for block deinterleaving and unmixing the decrypted frames, and for block interleaving and mixing the frames to be transmitted,

encoding and decoding means for encoding and decoding channel and speech coding, and

means for generating speech from the received speech frames, and for supplying the speech to be transmitted to the terminal.