Method and apparatus for data encoding and communication over noisy media

• US 5,944,842 A
• Filed: 06/17/1997
• Issued: 08/31/1999
• Est. Priority Date: 03/14/1995
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: Adaptive Networks, Inc.
• Inventors: Propp, Michael B., Propp, David L.
• Primary Examiner(s): MOISE, EMMANUEL LIONEL
• Application Number:
  US08/876,385
• Time in Patent Office: 805 Days
• Field of Search: 371/43.1, 371/43.2, 371/43.3, 371/43.4, 371/44, 371/45, 371/46, 371/47.1, 371/37.01, 371/38.1, 371/2.1, 371/39.1, 371/41, 375/243
• US Class Current: 714/701
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/709 Correlator structure
• CPC Class Codes: H04B 2203/5408 using protocols
• CPC Class Codes: H04B 2203/5416 by adding signals to the wave form of the power source
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5441 Wireless systems or telephone
• CPC Class Codes: H04B 2203/5495 having measurements and testing channel
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/1829 Arrangements specially adapted for the receiver end
• CPC Class Codes: H04L 2007/047 using a sine signal or unmodulated carrier
• CPC Class Codes: H04L 7/0337 Selecting between two or more discretely delayed clocks or selecting between two or more discretely delayed received code signals
• CPC Class Codes: H04L 7/041 using special codes as synchronising signal
• CPC Class Codes: H04L 7/042 Detectors therefor, e.g. correlators, state machines digital correlators in general G06F17/15
• CPC Class Codes: H04L 7/046 using a dotting sequence

Abstract

A novel apparatus and method are provided for data communication over noisy media. The apparatus includes one or both of a transmitter circuit located at a transmitting location and a receiver circuit located at a receiving location. The data is encoded to provide error correction capabilities. The encoded signal is further modified by performing one or more linear mathematical operations in order to further randomize the data signal. The transmitter circuit thus generates a wideband spread spectrum signal based on the data which is to be transmitted, which spreads the signal and improves its immunity to noise. The coding used to spread the data signal may or may not be a function of the data itself. The present invention provides enhanced noise immunity without any resulting degradation in the operation and efficiency of the error correction coding. A synchronization circuit and method are also provided for quickly achieving fast, accurate synchronization utilizing parallel synchronization and sub-bit correlation. The error correction is used to correct hard and soft errors, and dynamically adjust the combination of hard and soft errors corrected in order to improve the overall data error correction.

Claims

1. A method of encoding error correcting data signals to increase the randomness of the data signals without decreasing error correcting capabilities and effective signal bandwidth, comprising the steps of:

encoding data signals to produce encoded error correcting data signals; and

randomizing the encoded error correcting data signals using at least one linear operator, including the steps of;

XORing the encoded error correcting data with a pre-selected sequence to generate a codeword having a plurality of bits; and

re-arranging the plurality of bits of the codeword on a bit-by-bit basis using non-uniform bit separation.

2. The method of claim 1, wherein said at least one linear operator includes a permute operator for performing the step of re-arranging the plurality of bits.

3. The method of claim 2, wherein the permute operator is defined as (2, 3, 20, 19, 8, 18, 12, 4, 1, 5, 6, 10, 13, 11, 22, 16, 14, 7, 9, 0, 17, 21, 15, 23) for performing the step of re-arranging of the plurality of bits on a bit-by-bit basis.

4. The method of claim 1, wherein said at least one linear operator includes an offset operator for performing the step of XORing the encoded error correcting data.

5. The method of claim 4, wherein the offset operator is defined as hexadecimal 010804 as the pre-selected sequence.

6. A data encoder circuit for encoding error correcting data signals, comprising:

an encoder which encodes data signals to produce encoded error correcting data signals; and

a randomizer which performs at least one linear operation on said encoded error correcting data signals by XORing the encoded error correcting data with a pre-selected sequence to generate a codeword having a plurality of bits, and by re-arranging the plurality of bits of the codeword on a bit-by-bit basis using non-uniform bit separation, thereby increasing the randomness of the encoded error correcting data signals without decreasing error correcting capabilities and effective signal bandwidth.

7. The circuit of claim 6, wherein said at least one linear operation includes a permute operation for performing the step of re-arranging the plurality of bits.

8. The circuit of claim 7, wherein the permute operation is defined as (2, 3, 20, 19, 8, 18, 12, 4, 1, 5, 6, 10, 13, 11, 22, 16, 14, 7, 9, 0, 17, 21, 15, 23) for performing the step of re-arranging of the plurality of bits on a bit-by-bit basis.

9. The circuit of claim 6, wherein said at least one linear operation includes an offset operation for performing the step of XORing the encoded error correcting data.

10. The circuit of claim 9, wherein the offset operation is defined as hexadecimal 010804 as the pre-selected sequence.

11. A method of encoding error correcting data signals to increase the randomness of the data signals without decreasing error correcting capabilities and effective signal bandwidth, comprising the steps of:

(a) encoding data signals to produce encoded error correcting data signals;

(b) randomizing the encoded error correcting data signals using a polynomial operator; and

randomizing the randomized encoded error correcting data signals using at least one linear operator to rearrange the data signals in a codeword on a bit-by-bit basis to have nonuniform bit separation.

12. The method of claim 11, wherein the step (a) of randomizing includes the step of:

(a1) randomizing the encoded error correcting data signals by Golay coding using the polynomial operator.

13. The method of claim 11, wherein the step (b) of randomizing includes the steps of:

(b1) XORing the encoded error correcting data with a preselected sequence to generate a codeword having a plurality of bits; and

(b2) re-arranging the plurality of bits of the codeword on a bit-by-bit basis.

14. The method of claim 13, wherein said at least one linear operator includes a permute operator.

15. The method of claim 14, wherein the permute operator is defined as (2, 3, 20, 19, 8, 18, 12, 4, 1, 5, 6, 10, 13, 11, 22, 16, 14, 7, 9, 0, 17, 21, 15, 23).

16. The method of claim 13, wherein said at least one linear operator includes an offset operator.

17. The method of claim 16, wherein the offset operator is defined as hexadecimal 010804.