System and method of an in-band modem for data communications over digital wireless communication networks

• US 8,958,441 B2
• Filed: 06/03/2009
• Issued: 02/17/2015
• Est. Priority Date: 06/05/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Werner, Marc W., Pietsch, Christian, Sgraja, Christian, Granzow, Wolfgang, Joetten, Christoph A., Huang, Pengjun, Leung, Nikolai K N
• Primary Examiner(s): Thier, Michael
• Assistant Examiner(s): MENSAH, PRINCE AKWASI
• Application Number:
  US12/477,608
• Publication Number:
  US 20090304057A1
• Time in Patent Office: 2,085 Days
• Field of Search: 370/252, 370/328, 370/335, 370/338, 370/428, 370/493, 370/522, 370/503, 455/426, 455/493, 455/550, 455/556, 455/557, 455/572, 455/575, 455/7, 455/9, 455/24, 455/68, 455/423, 455/425, 455/447, 455/450
• US Class Current: 370/493
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1858 Transmission or retransmission of more than one copy of acknowledgement message
• CPC Class Codes: H04L 1/189 Transmission or retransmission of more than one copy of a message

Abstract

A system is provided for transmitting information through a speech codec (in-band) such as found in a wireless communication network. A modulator transforms the data into a spectrally noise-like signal based on the mapping of a shaped pulse to predetermined positions within a modulation frame, and the signal is efficiently encoded by a speech codec. A synchronization sequence provides modulation frame timing at the receiver and is detected based on analysis of a correlation peak pattern. A request/response protocol provides reliable transfer of data using message redundancy, retransmission, and/or robust modulation modes dependent on the communication channel conditions.

Claims

1. A method of controlling source terminal transmissions, the method comprising:

detecting a request signal at a source terminal in an in-band communication system;

transmitting a synchronization signal from the source terminal upon detection of the request signal;

repeatedly receiving alternating negative acknowledgment (NACK) signals and synchronization signals at the source terminal, wherein the alternating NACK signals and synchronization signals indicate successful reception of the transmitted synchronization signal from a destination terminal;

repeatedly transmitting a user data segment from the source terminal using a first modulation scheme, wherein each transmission uses a different redundancy version;

discontinuing transmission of the user data segment upon detection of a first received signal, wherein the first received signal indicates a successful reception of the user data segment from the destination terminal; and

switching to a second modulation scheme if the source terminal receives a predetermined number of the NACK signals, wherein the NACK signals further indicate an unsuccessful reception of the user data segment from the destination terminal, and wherein the predetermined number is greater than one.

2. The method of claim 1 wherein the request signal is a start signal detected on a downlink.

3. The method of claim 1 wherein the request signal is a user initiated action at the source terminal.

4. The method of claim 1 wherein the request signal is a sensor signal detected at the source terminal.

5. The method of claim 1 wherein the step of transmitting a synchronization signal is preceded by transmitting a send signal, and discontinuing transmission of the send signal upon detection of a second received signal, wherein the second received signal indicates a successful reception of the send signal from the destination terminal.

6. The method of claim 5, wherein the send signal is comprised of a synchronization signal followed by a send message.

15. The method of claim 1, wherein the request signal is a start signal, and the destination terminal is constrained to repeatedly transmit the start signal until the transmitted synchronization signal is received by the destination terminal.

16. The method of claim 1, wherein the destination terminal is constrained to discontinue transmission of the NACK signals and synchronization signals upon reception of the user data segment.

17. The method of claim 1, wherein the first received signal comprises an acknowledge (ACK) signal.

18. The method of claim 17, wherein the destination terminal is constrained to repeatedly transmit the ACK signal to the source terminal until a predetermined number of the ACK signals have been transmitted.

19. The method of claim 1, wherein a duration of a modulation frame of the second modulation scheme is greater than a duration of a modulation frame of the first modulation scheme.

20. The method of claim 19, wherein the first modulation scheme and the second modulation scheme have a same number of time instances.

7. An apparatus for controlling source terminal transmissions, the apparatus comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory, the instructions being capable of executing the steps of;

detecting a request signal at a source terminal in an in-band communication system;

transmitting a synchronization signal from the source terminal upon detection of the request signal;

repeatedly receiving alternating negative acknowledgment (NACK) signals and synchronization signals at the source terminal, wherein the alternating NACK signals and synchronization signals indicate successful reception of the transmitted synchronization signal from a destination terminal;

repeatedly transmitting a user data segment from the source terminal using a first modulation scheme, wherein each transmission uses a different redundancy version;

discontinuing transmission of the user data segment upon detection of a first received signal, wherein the first received signal indicates a successful reception of the user data segment from the destination terminal; and

switching to a second modulation scheme if the source terminal receives a predetermined number of the NACK signals, wherein the NACK signals further indicate an unsuccessful reception of the user data segment from the destination terminal, and wherein the predetermined number is greater than one.

8. The apparatus of claim 7 wherein the request signal is a start signal detected on a downlink.

9. The apparatus of claim 7 wherein the request signal is a user initiated action at the source terminal.

10. The apparatus of claim 7 wherein the request signal is a sensor signal detected at the source terminal.

11. The apparatus of claim 7 wherein the memory further comprises instructions preceding the instructions of transmitting a synchronization signal, the instructions being executable to transmit a send signal, and discontinuing transmission of the send signal upon detection of a second received signal, wherein the second received signal indicates a successful reception of the send signal from the destination terminal.

12. The apparatus of claim 11 wherein the send signal is comprised of a synchronization signal followed by a send message.

13. An apparatus for controlling source terminal transmissions, the apparatus comprising:

means for detecting a request signal at a source terminal in an in-band communication system;

means for transmitting a synchronization signal from the source terminal upon detection of the request signal;

means for repeatedly receiving alternating negative acknowledgment (NACK) signals and synchronization signals at the source terminal, wherein the alternating NACK signals and synchronization signals indicate successful reception of the transmitted synchronization signal from a destination terminal;

means for repeatedly transmitting a user data segment from the source terminal using a first modulation scheme, wherein each transmission uses a different redundancy version;

means for discontinuing transmission of the user data segment upon detection of a first received signal, wherein the first received signal indicates a successful reception of the user data segment from the destination terminal; and

means for switching to a second modulation scheme if the source terminal receives a predetermined number of the NACK signals, wherein the NACK signals further indicate an unsuccessful reception of the user data segment from the destination terminal, and wherein the predetermined number is greater than one.

14. The apparatus of claim 13, further comprising means for transmitting a send signal prior to the synchronization signal, and discontinuing transmission of the send signal upon detection of a second received signal, wherein the second received signal indicates a successful reception of the send signal from the destination terminal.