MODEM SIGNALING USING A MULTITONE PREFIX OVER A VOICE CHANNEL OF A WIRELESS COMMUNICATION SYSTEM

• US 20110249714A1
• Filed: 10/11/2010
• Published: 10/13/2011
• Est. Priority Date: 10/22/2009
• Status: Active Grant

• Current Assignee: General Motors LLC (General Motors Company), GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors LLC (General Motors Company), GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Surti, Iqbal M., Madhavan, Sethu K., Yi, Ki Hak, MacDonald, Andrew J., Saraydar, Cem U.
• Granted Patent: US 9,225,844 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• CPC Class Codes: G07C 5/008 communicating information to a remotely located station transmission systems for measured values G08C
• CPC Class Codes: H04M 11/066 Telephone sets adapted for data transmision
• CPC Class Codes: H04M 11/068 using time division multiplex techniques; integrated services digital networks H04Q11/0428

Abstract

A system and method of communicating data between a vehicle and call center via a voice channel of a wireless communication system. The method carried out by the system includes the steps of: establishing a voice channel connection between a vehicle telematics unit and call center via a wireless cellular network; generating a modem signaling carrier comprising a prefix followed by a single frequency tone; sending the modem signaling carrier over the voice channel connection using an EVRC-B vocoder; establishing a data communication session over the voice channel connection in response to the modem signaling carrier; and thereafter carrying out data communications between the vehicle telematics unit and call center during the data communication session.

Claims

1. A method of communicating with a modem via a voice channel of a wireless communication system, comprising the steps of:

generating a composite carrier comprising a prefix together with a tone having at least one frequency component; and

sending the composite carrier across a voice channel of a wireless communication system.

2. The method set forth in claim 1, wherein the generating step further comprises generating the composite carrier such that the prefix precedes the tone without being superimposed on the tone.

3. The method set forth in claim 1, wherein the generating step further comprises generating the composite carrier such that it includes three portions that together repeat one or more time, the three portions including the prefix, the tone, and a period of silence during which no tones are sent.

4. The method set forth in claim 1, wherein a relative duty cycle of the prefix is less than 20% of the prefix and tone together.

5. The method set forth in claim 1, wherein the prefix comprises multiple spectral components in the audio frequency range that each different amplitudes relative to each other.

6. The method set forth in claim 5, wherein the prefix is a speech component that comprises human speech.

7. The method set forth in claim 5, wherein the prefix is a speech component that comprises synthesized speech.

8. The method set forth in claim 5, wherein the tone is continuous and the prefix is intermittent.

9. The method set forth in claim 1, wherein the sending step further comprises sending the composite carrier over the voice channel of a cellular communications network from a first modem located at a vehicle to a second modem located at a call center using vocoders that process the composite carrier before and after the composite carrier is sent over the voice channel.

10. A method of communicating data between a vehicle and call center via a voice channel of a wireless communication system, comprising the steps of:

establishing a voice channel connection between a vehicle telematics unit and call center via a wireless cellular network;

generating a modem signaling carrier comprising a prefix followed by a single frequency tone;

sending the modem signaling carrier over the voice channel connection using an EVRC-B vocoder;

establishing a data communication session over the voice channel connection in response to the modem signaling carrier; and

thereafter

carrying out data communications between the vehicle telematics unit and call center during the data communication session.

11. The method set forth in claim 10, wherein the generating step further comprises generating the composite carrier such that the prefix precedes the tone without being superimposed on the tone.

12. The method set forth in claim 10, wherein the generating step further comprises generating the composite carrier such that it includes three portions that together repeat one or more time, the three portions including the prefix, the tone, and a period of silence during which no tones are sent.

13. The method set forth in claim 10, wherein a relative duty cycle of the prefix is less than 20% of the prefix and tone together.

14. The method set forth in claim 10, wherein the prefix comprises multiple spectral components in the audio frequency range that each different amplitudes relative to each other.

15. The method set forth in claim 14, wherein the prefix is a speech component that comprises human speech.

16. The method set forth in claim 14, wherein the prefix is a speech component that comprises synthesized speech.

17. The method set forth in claim 14, wherein the tone is continuous and the prefix is intermittent.