Voice fallback origination for vehicle cellular communication with a call center
View Patent ↗A system and method for making vehicle originated calls to a telematics service provider or other call center. The method includes identifying a call type associated with a desired wireless communication of speech or data to the call center, and then carrying out one of a number of different call connection processes depending on the call type. For voice channel cellular connections, an in-band modem cellular connection is preferably established in most instances using a connection retry strategy that includes primary, secondary, and possibly tertiary connection attempts each of which utilize at least one of a number of different voice and data call origination processes. The system and method can be carried out in connection with various cellular system technologies, but is especially suited for use with GSM systems.
1. A cellular voice channel origination method for use by a vehicle telematics unit to establish a voice call between the telematics unit and a call center, comprising the steps of:
(a) attempting a radio resource connection from the telematics unit to a wireless cellular system;
(b) initiating a mobile originated call to a call center via the wireless cellular system;
(c) monitoring at the telematics unit for receipt of a connect message;
(d) sending a connect acknowledgement message in response to receipt of the connect message and receiving a return acknowledgement, thereby establishing the voice call between the telematics unit and call center; and
(e) connecting the call to an advisor at the call center.
2. A cellular voice channel origination method as defined in claim 1 , further comprising, prior to the step (b), the step of sending a service request via a standalone dedicated control channel of the wireless cellular system.
3. A cellular voice channel origination method as defined in claim 1 , wherein step (c) further comprises monitoring for receipt of the connect message over a fast associated control channel of the wireless cellular system.
4. A cellular voice channel origination method as defined in claim 1 , further comprising the step of carrying out multiple iterations of steps (a) through (c) until the connect message is received or until a specified maximum number of iterations have occurred.
5. A cellular voice channel origination method as defined in claim 1 , further comprising the step of using a data compatible modem at the telematics unit to establish an in-band modem cellular connection between the telematics unit and call center after the voice call is established.
6. A cellular voice channel origination method as defined in claim 1 , wherein step (d) further comprises the steps of determining that the data mode session is successfully established in response to receiving an acknowledgement signal, and carrying out a call re-establishment procedure if the acknowledgement signal is not received.
7. A cellular voice channel origination method as defined in claim 1 , further comprising the step of carrying out multiple iterations of steps (a) through (c) and incrementing a counter during each iteration if the connect message is not received.
8. A cellular voice channel origination method as defined in claim 1 , further comprising the steps of starting a timer at least prior to step (b) and carrying out steps (c) through (e) if the timer has not expired prior to completion of step (b).
9. A cellular voice channel origination method as defined in claim 8 , further comprising repeating steps (a) and (b) if the timer has expired prior to the completion of step (b).
10. A cellular voice channel origination method for use by a vehicle telematics unit to provide a wireless communication from the telematics unit to a call center, comprising the steps of:
(a) initializing a counter;
(b) starting a connection timer;
(c) attempting a radio resource connection from the telematics unit to a wireless cellular system;
(d) sending a service request via a standalone dedicated control channel of the wireless cellular system;
(e) initiating a mobile originated call to a call center via the wireless cellular system;
(f) monitoring at the telematics unit for receipt of a connect message over a fast associated control channel of the wireless cellular system;
(g) incrementing the counter if the connect message is not received before expiration of the timer and then repeating steps (b) through (f) after incrementing the counter;
(h) sending a connect acknowledgement message in response to receipt of the connect message and receiving a return acknowledgement, thereby establishing the voice call between the telematics unit and call center; and
(i) repeating at least steps (b) through (f) until the voice call is successfully established or the counter reaches a specified maximum limit.
11. A cellular voice channel origination method as defined in claim 10 , further comprising the step of connecting the call to an advisor at the call center.
12. A cellular voice channel origination method as defined in claim 11 , further comprising the steps of determining that there has been a radio link failure and attempting re-establishment.
13. A cellular voice channel origination method as defined in claim 12 , further comprising the steps of attempting re-establishment of the mobile originated call if there is a radio link failure and repeating step (h) if the re-establishment is successful.
14. A cellular voice channel origination method as defined in claim 10 , further comprising the step of incrementing the counter if the radio resource connection is not established.