Call-back method in response to emergency call originating from cellular radiotelephone

• US 6,038,437 A
• Filed: 02/13/1997
• Issued: 03/14/2000
• Est. Priority Date: 02/13/1997
• Status: Expired due to Term

• Current Assignee: GTE Mobilnet Service Corporation
• Original Assignee: GTE Mobilnet Service Corporation
• Inventors: Zicker, Robert G.
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Smith, Sheila B.
• Application Number:
  US08/799,906
• Time in Patent Office: 1,125 Days
• Field of Search: 455/404, 455/432, 455/436, 455/439, 455/422, 455/524, 455/519, 455/550, 455/575, 455/560
• US Class Current: 455/404.1
• 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 originates from a cellular radiotelephone (20) and communicates through one of A-side and B-side cellular systems. Upon receipt of the call, the cellular radiotelephone (20) is assigned a temporary substitute Mobile Identification Number (MIN) (100) by the receiving A-side or B-side cellular system MTSO (33). Upon termination of the emergency call, a call-back to the cellular radiotelephone (20) is routed to both of the A-side and B-side MTSOs (100), using the substitute MIN (100), by the Public Switched Telecommunications Network (36). Both A-side and B-side MTSOs (100) issue a page order message to cellular radiotelephone (20) by transmitting to the MIN (74). Paging order confirmation messages (78), conveying the MIN (74), are evaluated for a match with a unique Electronic Serial Number (76).

Claims

1. A method of operating a mobile telephone switching office (MTSO) to provide call-back to a cellular radiotelephone following an emergency call, said method comprising the steps of:

(a) detecting an emergency call from a cellular radiotelephone;

(b) obtaining an identity code for said radiotelephone, said identity code being comprised of a radiotelephone mobile identification number (MIN) and a radiotelephone Electronic Serial Number (ESN);

(c) assigning said cellular radiotelephone a substitute MIN;

(d) enabling said call from said radiotelephone to a Public Safety Answering Position (PSAP);

(e) detecting a return call to said substitute MIN;

(f) extracting, in response to said step (e), said radiotelephone MIN from said identity code;

(f) transmitting a paging message addressed to said radiotelephone MIN;

(g) receiving a first one of a plurality of paging confirmation messages, in response to said step (f), over a reverse channel, each of said plurality of paging confirmation messages conveying said radiotelephone MIN;

(h) transmitting a message over a forward control channel indicating said reverse control channel is busy;

(i) processing said first paging confirmation message;

(j) determining whether said first paging confirmation message conveys said radiotelephone ESN;

(k) if said first paging confirmation message conveys said radiotelephone ESN, allocating a voice channel; and

(l) if said first paging confirmation message does not convey said radiotelephone ESN, repeating said steps (g)-(j) for a second one of said plurality of confirmation messages.

2. A method of operating a mobile telephone switching office (MTSO) to provide call-back to a cellular radiotelephone following an emergency call, said method comprising the steps of:

(a) detecting an emergency call from a cellular radiotelephone at a first one of an A-side cellular system and a B-side cellular system;

(b) obtaining an identity code for said radiotelephone;

(c) assigning said cellular radiotelephone a substitute mobile identification number (MIN);

(d) notifying a second one of said A-side and B-side cellular systems of said identity code and said substitute MIN;

(e) enabling said call from said radiotelephone to a Public Safety Answering Position (PSAP);

(f) detecting a return call to said substitute MIN; and

(g) paging, in response to said step (f), said radiotelephone assigned said substitute MIN.

3. A method of operating a mobile telephone switching office (MTSO) to provide call-back to a cellular radiotelephone following an emergency call, said method comprising the steps of:

(a) detecting a first emergency call from a cellular radiotelephone at a first one of an A-side cellular system and a B-side cellular system;

(b) assigning said cellular radiotelephone a first substitute mobile identification number (MIN);

(c) enabling said first call from said radiotelephone to a Public Safety Answering Position (PSAP);

(d) detecting a first return call to said first substitute MIN;

(e) paging, in response to said step (d), said radiotelephone assigned said first substitute MIN;

(f) receiving notification of a second identity code and a second substitute MIN from a second one of said A-side and B-side systems, said second identity code and second substitute MIN being associated with a second emergency call;

(g) detecting a second return call directed to said second substitute MIN; and

(h) transmitting a page order directed to said second identity code.

4. A method of operating a mobile telephone switching office (MTSO) for a first one of an A-side cellular system and a B-side cellular system to provide call-back to a cellular radiotelephone following an emergency call, said method comprising the steps of:

(a) detecting an emergency call initiated by said cellular radiotelephone;

(b) obtaining an identity code for said cellular radiotelephone;

(c) assigning said cellular radiotelephone a substitute mobile identification number (MIN) from a list of substitute MINs accessible by said A-side and B-side cellular systems;

(d) storing said identity code in association with said substitute MIN;

(e) notifying a second one of said A-side and B-side systems of said identity code and said substitute MIN;

(f) enabling said call from said radiotelephone to a Public Safety Answering Position (PSAP);

(g) detecting a return call directed to said substitute MIN; and

(h) paging, in response to said step (g), said radiotelephone assigned said substitute MIN.

5. A method of operating a mobile telephone switching office (MTSO) for a first one of an A-side cellular system and a B-side cellular system to provide call-back to a cellular radiotelephone following an emergency call, said method comprising the steps of:

(a) detecting a first emergency call initiated by said cellular radiotelephone;

(b) obtaining a first identity code for said cellular radiotelephone;

(c) assigning said cellular radiotelephone a first substitute mobile identification number (MIN) from a list of substitute MINs accessible by said A-side and B-side cellular systems;

(d) storing said first identity code in association with said first substitute MIN;

(e) enabling said first emergency call from said radiotelephone to a Public Safety Answering Position (PSAP);

(f) detecting a first return call directed to said first substitute MIN;

(g) paging, in response to said step (f), said radiotelephone assigned said first substitute MIN;

(h) receiving notification of a second identity code and a second substitute MIN from a second one of said A-side and B-side systems, said second identity code and second substitute MIN being associated with a second emergency call;

(i) detecting a second return call directed to said second substitute MIN; and

(j) transmitting a page order directed to said second identity code.