Emergency call handling in a cellular telecommunication system

• US 5,937,355 A
• Filed: 08/08/1997
• Issued: 08/10/1999
• Est. Priority Date: 12/07/1995
• Status: Expired due to Term

• Current Assignee: Blackberry Limited
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Joong, Donald, Katinakis, Nikos, Rahman, Akbar
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US08/908,772
• Time in Patent Office: 732 Days
• Field of Search: 455/466, 370/111, 370/8, 379/106, 379/45, 379/91, 379/40, 379/106.1, 379/91.01, 375/283
• US Class Current: 455/466
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 76/50 for emergency connections

Abstract

An emergency call handling system and method for a cellular telecommunications system. The emergency call handling system is provided with at least one subscriber terminal which upon failure to seize a voice connection to an emergency center for an emergency call, transfers data messages over the digital control channel to the emergency center advising it that the user of this one subscriber terminal has an emergency situation. Advantage is found with the present invention in that in times of radio voice channel and/or network traffic congestion resulting in call set up failure, the information relating to a user emergency can be forwarded as data messages to the emergency center.

Claims

1. An emergency call handling system within a cellular communication system for routing emergency voice calls and short message service (SMS) messages from a plurality of subscriber terminals to an emergency center (EC), said system comprising:

a mobile switching center (MSC) for controlling signaling with a plurality of base stations (BS'"'"'s); and

at least one subscriber terminal normally communicating with the MSC through one BS over a digital control channel (DCC) when in an idle mode and a voice channel (VC) when in an active subscriber communication mode, said one terminal including;

emergency call means within the terminal for initiating an emergency voice call via the BS through the MSC to the EC;

call failure detection means within the terminal for detecting when the emergency voice call has failed to be set up with the EC; and

data transmission means within the terminal responsive to a call failure detection for transmitting an emergency SMS message over the DCC through the BS and MSC to the EC while not affecting the operation of the DCC as a control channel.

2. The emergency call handling system of claim 1 wherein the MSC further includes means to selectively route the emergency SMS message to the EC while routing non-emergency SMS messages to a SMS message center.

3. The emergency call handling system of claim 1 wherein the EC includes acknowledgment means that upon receipt of the emergency SMS message from said one terminal transmits an acknowledgment SMS message to the MSC, through the BS and over the DCC to said one terminal.

4. The emergency call handling system of claim 1 wherein the EC includes call back means responsive to the emergency SMS message that sends a call back to said one terminal through the MSC, BS and over the VC.

5. The emergency call handling system of claim 1 wherein said emergency SMS message includes 1) data information identifying the SMS message as an emergency and 2) data information relating to the identity of the terminal.

6. The emergency call handling system of claim 5 wherein the emergency SMS message further includes user medical history information.

8. The emergency call handling system of claim 1 wherein the MSC includes means for analyzing the emergency SMS message and adding to said emergency SMS message forwarded to the EC location information corresponding to the location of said terminal.

9. The emergency call handling system of claim 1 wherein the call failure detection means includes count means which counts up to a predetermined number of consecutive emergency call failures and thereafter enables the data transmission means to transmit said emergency SMS message.

10. The emergency call handling system of claim 1 wherein the call failure detection means enables the data transmission means to transmit said emergency SMS message upon determination that a failure to set up a call over the VC to the EC is the result of congestion.

7. An emergency call handling system within a cellular communication system for routing emergency voice calls and short message service (SMS) messages from a plurality of subscriber terminals to an emergency center (EC), said system comprising:

a mobile switching center (MSC) for controlling signaling with a plurality of base stations (BS'"'"'s); and

at least one subscriber terminal normally communicating with the MSC through one BS over a digital control channel (DCC) when in an idle mode and a voice channel (VC) when in an active subscriber communication mode, said one terminal including;

emergency call means within the terminal for initiating an emergency voice call via the BS through the MSC to the EC;

call failure detection means within the terminal for detecting when the emergency voice call has failed to be set up with the EC; and

data transmission means within the terminal responsive to a call failure detection for transmitting an emergency SMS message over the DCC through the BS and MSC to the EC while not affecting the operation of the DCC as a control channel, the emergency SMS message including (1) data information identifying the SMS message as an emergency message, (2) data information relating to the identity of the terminal, and (3) data information corresponding to the location of the terminal.

11. An emergency call handling system within a cellular communication system having a plurality of cells and a plurality of subscriber terminals for routing emergency voice calls and short message service (SMS) messages from said subscriber terminals to an emergency center (EC), said system comprising:

a mobile switching center (MSC) including means to route said emergency voice calls to the EC;

a plurality of base stations (BS'"'"'s) electronically connected to said MSC, each of said BS'"'"'s transmitting radio frequency signals over at least one digital control channel and a plurality of voice channels over a coverage area defining one of said cells; and

at least one subscriber terminal normally communicating with the MSC via one of said BS'"'"'s over a corresponding channel selected from one of the group consisting of a digital control channel (DCC) and a voice channel (VC), said one terminal including;

emergency call means within the terminal for initiating an emergency voice call to the EC via the BS and the MSC;

call failure detection means within the terminal for detecting when the emergency voice call has failed to be set up with the EC; and

data transmission means within the terminal responsive to a call failure detection for transmitting an emergency SMS message over the DCC to the BS and through the MSC to the EC while not affecting the operation of the DCC as a control channel.

12. The emergency call handling system of claim 11 wherein the EC comprises a public safety answering point (PSAP).

13. The emergency call handling system of claim 11 wherein the EC includes acknowledgment means that upon receipt of the emergency SMS message from said one terminal transmits an acknowledgment SMS message to the MSC, through the BS and over the DCC to said one terminal.

14. The emergency call handling system of claim 11 wherein the EC includes call back means responsive to the emergency SMS message that sends a call back to said one terminal through the MSC, BS and over the VC.

15. The emergency call handling system of claim 11 wherein said emergency SMS message includes 1) data information identifying the SMS message as an emergency and 2) data information relating to the identity of the terminal.

16. The emergency call handling system of claim 15 wherein the emergency SMS message further includes user medical history information.

17. The emergency call handling system of claim 15 wherein said emergency SMS message further includes SMS information corresponding to the location of the terminal.

18. The emergency call handling system of claim 11 wherein the MSC includes means for analyzing the emergency SMS message and adding to said emergency SMS message forwarded to the EC location information corresponding to the location of said terminal.

19. The emergency call handling system of claim 11 wherein the call failure detection means includes count means which counts up to a predetermined number of consecutive emergency voice call failures and thereafter enables the data transmission means to transmit said emergency SMS message.

20. The emergency call handling system of claim 11 wherein the call failure detection means enables the data transmission means to transmit said emergency SMS message upon determination that a failure to set up a voice call over the VC to the EC is the result of congestion.

21. A method for emergency call handling in a cellular communication system for routing emergency voice calls and short message service (SMS) messages from a plurality of subscriber terminals to an emergency center (EC) via a mobile switching center (MSC) controlling a plurality of base stations (BS'"'"'s), said method comprising the steps of:

communicating from at least one of said subscriber terminals to the MSC over a digital control channel (DCC) and a voice channel (VC), said communicating step including;

initiating in the subscriber terminal, an emergency voice call to the EC over the VC to the BS and through the MSC to the EC,

detecting in the subscriber terminal, when the emergency voice call has failed to be set up with the EC, and

responsive to the subscriber terminal detecting a failed set up of the emergency voice call with the EC, transmitting from the subscriber terminal, an emergency SMS message over the DCC to the BS through the MSC while not affecting the operation of the DCC as a control channel, and

the MSC transmitting the emergency SMS message to the EC.

22. The emergency call handling method of claim 21 further including the step of the EC transmitting a SMS acknowledgment message to said one terminal through the MSC, BS and over the DCC upon receipt of the emergency SMS message.

23. The emergency call handling method of claim 21 further including the step of the EC initiating a call back through the MSC, BS and over the VC to said one terminal upon receipt of the emergency SMS message.

24. The emergency call handling method of claim 21 wherein said emergency SMS message includes 1) data information identifying the SMS message as an emergency and 2) data information relating to the identity of the terminal.

26. The emergency call handling method of claim 21 further including the step of the MSC analyzing the emergency SMS message to determine if it is an emergency message, and adding to said emergency SMS message forwarded to the EC location information corresponding to the location of said terminal.

27. The emergency call handling method of claim 21 further including the step of said one terminal counting a predetermined number of emergency voice call failures and thereafter enabling said step of transmitting an emergency SMS message to said EC.

28. The emergency call handling method of claim 21 further including the step of detecting a failure to connect over a VC to the EC due to congestion and thereafter initiating the step of transmitting the emergency SMS message.

25. A method for emergency call handling in a cellular communication system for routing emergency voice calls and short message service (SMS) messages from a plurality of subscriber terminals to an emergency center (EC) via a mobile switching center (MSC) controlling a plurality of base stations (BS'"'"'s), said method comprising the steps of:

communicating from at least one of said subscriber terminals to the MSC over a digital control channel (DCC) and a voice channel (VC), said communicating step including;

initiating an emergency voice call to the EC over the VC to the BS and through the MSC to the EC,

detecting when the emergency voice call has failed to be set up with the EC, and responsive to detecting a failed set up of the emergency voice call with the EC, transmitting an emergency SMS message over the DCC to the BS through the MSC while not affecting the operation of the DCC as a control channel, said emergency data message including (1) data information identifying the SMS message as an emergency, (2) data information relating to the identity of the terminal, and (3) data information corresponding to the location of the terminal; and

the MSC transmitting the emergency SMS message to the EC.

29. An emergency call handling system for a cellular communication system for routing emergency voice calls and short message service (SMS) messages from a plurality of subscriber terminals to an emergency center (EC), said system comprising:

a mobile switching center (MSC) for controlling signaling with a plurality of base stations (BS'"'"'s);

at least one subscriber terminal normally communicating with the MSC through one BS, said one terminal including data transmission means for transmitting SMS messages including emergency SMS messages from the subscriber terminal over a digital control channel (DCC) through the BS to the MSC while not affecting the operation of the DCC as a control channel; and

data analyzing means in the MSC for analyzing the SMS messages received from said one terminal to selectively route emergency SMS messages to the EC while routing non-emergency SMS messages to a SMS message center.

30. The emergency call handling system of claim 29 wherein the EC includes acknowledgment means that upon receipt of the emergency SMS message transmits an acknowledgment SMS message to the MSC, through the BS and over the DCC to said one terminal.

31. The emergency call handling system of claim 29 wherein the EC includes call back means responsive to the emergency SMS message that initiates a call back to said one terminal through the MSC, BS and over a voice channel (VC).

32. The emergency call handling system of claim 29 wherein said emergency SMS message includes 1) data information identifying the SMS message as an emergency and 2) data information relating to the identity of the terminal.

33. The emergency call handling system of claim 32 wherein the emergency SMS message further includes user medical history information.

35. The emergency call handling system of claim 29 wherein the means for analyzing the emergency SMS message includes means for adding to said emergency SMS message forwarded to the EC location information corresponding to the location of said terminal.

36. The emergency call handling system of claim 29 further including call failure detection means for detecting when an emergency voice call to the EC has failed to be set up and, responsive thereto, enabling the data transmission means to transmit the emergency SMS message.

37. The emergency call handling system of claim 36 wherein the call failure detection means includes count means which counts up to a predetermined number of emergency voice call failures and thereafter enables the data transmission means to transmit said emergency SMS message.

38. The emergency call handling system of claim 36 wherein the call failure means enables the data transmission means to transmit said emergency SMS message upon determination that a failure to set up an emergency voice call with the voice channel to the EC is the result of congestion.

34. An emergency call handling system for a cellular communication system for routing emergency voice calls and short message service (SMS) messages from a plurality of subscriber terminals to an emergency center (EC), said system comprising:

a mobile switching center (MSC) for controlling signaling with a plurality of base stations (BS'"'"'s);

at least one subscriber terminal normally communicating with the MSC through one BS, said one terminal including data transmission means for transmitting SMS messages including emergency SMS messages over a digital control channel (DCC) through the BS to the MSC while not affecting the operation of the DCC as a control channel, said emergency SMS messages including (1) data information identifying the data message as an emergency, (2) data information relating to the identity of the terminal, and (3) data information corresponding to the location of the terminal; and

data analyzing means in the MSC for analyzing the SMS messages received from said one terminal to route emergency SMS messages to the EC.

39. A method for emergency call handling in a cellular communication system for routing emergency voice calls and short message service (SMS) messages from a plurality of subscriber terminals to an emergency center (EC) via a mobile switching center (MSC) controlling a plurality of base stations (BS'"'"'s), said method comprising the steps of:

transmitting, from at least one subscriber terminal, SMS messages, including emergency SMS messages, over a digital control channel (DCC) through the BS to the MSC while not affecting the operation of the DCC as a control channel;

determining in the MSC, whether SMS messages received from said one subscriber terminal are emergency SMS messages;

routing said SMS messages to the EC upon determining that said SMS messages are emergency SMS messages; and

routing said SMS messages to a SMS message center upon determining that said SMS messages are not emergency SMS messages.

40. The emergency call handling method of claim 39 further including the step of the EC transmitting a SMS acknowledgment message to said one terminal through the MSC, BS and over a digital control channel upon receipt of the emergency SMS message to said one terminal.

41. The emergency call handling method of claim 39 further including the step of the EC initiating a call back to through the MSC, BS and over a voice to said one terminal after receipt of the emergency SMS message.

42. The emergency call handling method of claim 39 wherein said emergency SMS message includes 1) data information identifying the SMS message as an emergency and 2) data information relating to the identity of the terminal.

44. The emergency call handling method of claim 39 further including the step of the MSC adding location information to said emergency SMS message forwarded to the EC corresponding to the location of said terminal.

45. The emergency call handling method of claim 39 further including the steps of detecting when an emergency voice call to the EC has failed to be set up and, responsive thereto, enabling the step of transmitting the emergency SMS messages.

46. The emergency call handling system of claim 45 wherein the detecting step includes counting up to a predetermined number of emergency voice call failures and thereafter enabling the step of transmitting the emergency SMS messages.

43. A method for emergency call handling in a cellular communication system for routing emergency voice calls and short message service (SMS) messages from a plurality of subscriber terminals to an emergency center (EC) via a mobile switching center (MSC) controlling a plurality of base stations (BS'"'"'s), said method comprising the steps of:

transmitting, from at least one subscriber terminal, SMS messages, including emergency SMS messages, over a digital control channel (DCC) through the BS to the MSC while not affecting the operation of the DCC as a control channel, said emergency data messages including (1) data information identifying the data message as an emergency, (2) data information relating to the identity of the terminal, and (3) data information corresponding to the location of the terminal;

determining in the MSC, whether SMS messages received from said one subscriber terminal are emergency SMS messages; and

routing said SMS messages to the EC upon determining that said SMS messages are emergency SMS messages.