Time diversity voice channel data communications

• US 20070264964A1
• Filed: 05/26/2006
• Published: 11/15/2007
• Est. Priority Date: 04/07/2006
• Status: Active Grant

• Current Assignee: Karma Automotive LLC (Wanxiang Group Corporation)
• Original Assignee: Airbiquity Incorporated
• Inventors: Birmingham, Kiley
• Granted Patent: US 7,924,934 B2
• Time in Patent Office: Days
• US Class Current: 455/403
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04M 11/066 Telephone sets adapted for data transmision

Abstract

A receiver with a time diversity combining component recovers a digital data signal transmitted over a voice channel of a digital wireless telecommunications network. A feature extraction module receives an audio frequency waveform encoding the digital data signal and generates a feature vector representing the digital data signal. A bit sequence estimation module analyzes the feature vector and generates an estimated bit sequence corresponding to the digital data signal. A memory stores the feature vector if the estimated bit sequence contains errors. A time diversity combining component generates a second estimated bit sequence by analyzing the first feature vector in combination with one or more feature vectors stored in the memory.

Claims

1. A receiver for recovering a digital data signal transmitted over a digital voice channel of a wireless telecommunications network comprising:

a feature extraction module configured to receive an audio frequency waveform encoding the digital data signal transmitted over the digital voice channel of the wireless telecommunications network and generate a first feature vector describing the audio frequency waveform;

a memory configured to store one or more feature vectors; and

a bit sequence estimation module configured to analyze the first feature vector and generate a first estimated bit sequence corresponding to the digital data signal,

wherein the bit sequence estimation module comprises a time diversity combining component configured to generate a second estimated bit sequence by analyzing the first feature vector in combination with one or more feature vectors stored in the memory.

2. A receiver according to claim 1, further comprising an inband signaling modem configured to demodulate the digital data signal.

3. A receiver according to claim 1, wherein each feature vector comprises a sequence of Fourier magnitudes or a sequence of cross-correlation values.

4. A receiver according to claim 1, wherein the one or more feature vectors have about 80% or more bits in common with the first feature vector.

5. A receiver according to claim 1, further comprising an error detection module configured to check for errors within first and second estimated bit sequences.

6. A receiver according to claim 1, wherein the bit decision rule module comprises an error correction component configured to implement a selected forward error correction method.

7. A receiver according to claim 6, wherein the selected forward error correction method comprises BCH, Reed-Solomon, or convolutional error correction.

8. A receiver according to claim 1, further comprising an error detection module configured to implement a CRC error checking algorithm.

9. A method for recovering a digital data signal transmitted over a digital voice channel of a wireless telecommunications network comprising:

extracting a first feature vector from an audio frequency waveform encoding the digital data signal transmitted over the digital voice channel of the wireless telecommunications network;

generating a first estimated bit sequence based on the first feature vector;

checking for errors within the first estimated bit sequence;

storing the first feature vector in a memory module if the first estimated bit sequence contains errors;

selecting a second feature vector stored in the memory module;

generating a second estimated bit sequence based on a combination of the first feature vector and the second feature vector; and

checking for errors within the second estimated bit sequence.

10. A method according to claim 9, further comprising:

selecting one or more additional feature vectors stored in the memory module for combination with the first and second feature vectors;

generating one or more additional estimated bit sequences based on a combination of the first feature vector, the second feature vector, and the one or more additional feature vectors; and

checking for errors within the one or more additional estimated bit sequences.

11. A method according to claim 9, wherein selecting the second feature vector comprises determining whether the second feature vector is similar to the first feature vector.

12. A method according to claim 9, further comprising deleting the second feature vector from the memory module if the second estimated bit sequence does not contain errors.

13. A method according to claim 9, wherein generating the second estimated bit sequence comprises summing or averaging the first feature vector and the second feature vector.

14. A method according to claim 9, wherein the digital data signal is transmitted using an FSK modulation scheme or a PSK modulation scheme.

15. A method according to claim 9, wherein each feature vector comprises a sequence of Fourier magnitudes or a sequence of cross-correlation values.

16. A method according to claim 9, wherein the digital data is converted into synthesized data tones having frequencies within the range of about 200 Hertz to about 3500 Hertz.

17. A method according to claim 9, wherein the digital data is transmitted at a baud rate within the range of about 100 bits/second to about 500 bits/second.

18. A machine readable medium comprising machine readable instructions for causing a computer to perform a method for recovering a digital data signal transmitted over a digital voice channel of a wireless telecommunications network, the method comprising:

extracting a first feature vector from an audio frequency waveform encoding the digital data signal transmitted over the digital voice channel of the wireless telecommunications network;

generating a first estimated bit sequence based on the first feature vector;

checking for errors within the first estimated bit sequence;

storing the first feature vector in a memory module if the first estimated bit sequence contains errors;

selecting a second feature vector stored in the memory module;

generating a second estimated bit sequence based on a combination of the first feature vector and the second feature vector; and

checking for errors within the second estimated bit sequence.

19. A machine readable medium according to claim 18, wherein the method further comprises:

selecting one or more additional feature vectors stored in the memory module for combination with the first and second feature vectors;

generating one or more additional estimated bit sequences based on a combination of the first feature vector, the second feature vector, and the one or more additional feature vectors; and

checking for errors within the one or more additional estimated bit sequences.

20. A machine readable medium according to claim 18, wherein selecting the second feature vector comprises determining whether the second feature vector is similar to the first feature vector.