Rotationally invariant non-coherent burst coding and decoding

• US 8,095,850 B1
• Filed: 02/17/2010
• Issued: 01/10/2012
• Est. Priority Date: 09/25/2006
• Status: Active Grant

• Current Assignee: Alfred E. Mann Foundation For Scientific Research
• Original Assignee: Alfred E. Mann Foundation For Scientific Research
• Inventors: Karr, Lawrence J., Hess, Phillip B.
• Primary Examiner(s): Torres, Joseph D
• Application Number:
  US12/707,178
• Time in Patent Office: 692 Days
• Field of Search: 714/758, 714/781
• US Class Current: 714/758
• CPC Class Codes: H03M 13/1505 Golay Codes
• CPC Class Codes: H03M 13/251 with block coding
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04J 13/10 Code generation
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04L 1/0042 Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0058 Block-coded modulation

Abstract

An apparatus, system and method can be arranged for coding and/or decoding with a phase invariant coding scheme that is useful for short burst signaling devices. 10-bit data is mapped into a 12-bit data with a non-coherent burst code mapper. A parity generator creates a 12-bit parity data to form a 24-bit extended binary Golay code from the 12-bit data. The values for selected bit fields in the 12-bit data and 12-bit parity data are swapped to generate I and Q data such that sensitivity to changes in rotational phase is removed. I and Q data can be used by a transmitter to transmit a rotationally-invariant signal. On receipt, I and Q signals can be recovered, reverse swapped to generate the parity and data signals, and remapped to recover the transmitted 10-bit data. The receiver can also be arranged to use a soft decoding method for improved signal integrity.

Claims

1. A method for decoding information from a signal transmission that is encoded with a non-coherent burst code, the method comprising:

derotating a series of baseband samples associated with the signal transmission into in-phase and quadrature-phase portions, wherein the series of baseband samples include a combination of signals and noise associated with the signal transmission, wherein the series of baseband samples has an unknown rotation angle, and wherein the derotated series of baseband samples are aligned to a nominal rotation angle that corresponds to at least one of 45 degrees, 135 degrees, 225 degrees, and 315 degrees;

generating a 24-bit coded signal by hard-limiting the derotated series of baseband samples;

identifying a first set of bit positions for a first 12-bit portion of the 24-bit coded signal from a first portion of a 24-bit weight 12 template code;

identifying a second set of bit positions for a second 12-bit portion of the 24-bit coded signal from a second portion of the 24-bit weight 12 template code;

swapping a first set of bit values in the first set of bit positions for the 24-bit coded signal with a second set of bit values occupying the second set of bit positions for the 24-bit coded signal to provide a 24-bit data;

decoding a 12-bit data from the 24-bit code using an extended binary Golay decoder; and

remapping the 12-bit data to a 10-bit output data, wherein the 12-bit data corresponds to a mapping from 10-bit data space to 12-bit data space, wherein the mapping between the 10-bit data space and the 12-bit data space is determined by the 24-bit weight 12 template code.

2. The method of claim 1, further comprising:

identifying a first rotational phase for a first one of the 10-bit output data that is received at a first instance of time;

identifying a second rotational phase for a second one of the 10-bit output data that is received at a second instance of time, wherein the second instance of time occurs after the first instance of time; and

decoding a 2-bit output data at the second instance of time from a difference between the first rotational phase and the second rotational phase.

3. The method of claim 2, wherein the first rotational phase is indicated with a first quadrant signal, the second rotational phase is indicated with a second quadrant signal, and wherein decoding comprises applying an exclusive OR operation on the first quadrant signal and the second quadrant signal.

4. The method of claim 1, further comprising:

mapping the 10-bit output data to a 24-bit code;

correlating the 24-bit code with the series of baseband samples to provide a phase signal;

identifying a first phase signal for a first one of the 10-bit output data that is received at a first instance of time;

identifying a second phase signal for a second one of the 10-bit output data that is received at a second instance of time, wherein the second instance of time occurs after the first instance of time; and

decoding a 2-bit output data at the second instance of time from a difference between the first phase signal and the second phase signal.

5. The method of claim 1, further comprising:

ranking a signal strength associated with each bit from the derotated series of baseband samples

identifying bit positions in the 24-bit coded signal corresponding to bits that have a lowest signal strength in the ranking;

creating a list of all possible values for the identified bit positions;

cycling through possible bit values for the identified bit positions until all permutations of bit values are exhausted, by;

selecting a next permutation of bit values from the list;

modifying the identified bit positions in the 24-bit coded signal with the selected bit values;

reverse swapping a first set of bit values in the first set of bit positions for the 24-bit data with a second set of bit values occupying the second set of bit positions for the 24-bit data to provide a second 24-bit data; and

correlating the second 24-bit data with the derotated series of baseband samples to provide a correlation result for the selected permutation of bit values;

ranking the correlation results; and

selecting the highest ranked correlation result for the decoded 12-bit data.

6. The method of claim 5, further comprising:

identifying a first rotational phase for a first one of the 10-bit output data that is received at a first instance of time;

identifying a second rotational phase for a second one of the 10-bit output data that is received at a second instance of time, wherein the second instance of time occurs after the first instance of time; and

decoding a 2-bit output data at the second instance of time from a difference between the first rotational phase and the second rotational phase.

7. The method of claim 6, wherein the first rotational phase is indicated with a first quadrant signal, the second rotational phase is indicated with a second quadrant signal, and wherein decoding comprises applying an exclusive OR operation on the first quadrant signal and the second quadrant signal.

8. The method of claim 6, wherein the first rotational phase is indicated from a first phase output of a correlator at the first instance of time, and wherein the second rotation phase is indicated from a second phase output of the correlator at the second instance of time.