Systems and methods for message encoding and decoding

• US 8,316,274 B2
• Filed: 04/19/2010
• Issued: 11/20/2012
• Est. Priority Date: 10/24/2005
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Ry, Hans Westgaard, Persvold, Steffen, Bugge, Hakon
• Primary Examiner(s): Chase, Shelly A
• Application Number:
  US12/763,096
• Publication Number:
  US 20100205505A1
• Time in Patent Office: 946 Days
• Field of Search: 714/752, 714/758, 714/807, 714/774
• US Class Current: 714/752
• CPC Class Codes: H03M 13/09 Error detection only, e.g. using cyclic redundancy check [CRC] codes or single parity bit

Abstract

Presented herein are systems and methods for checking the integrity of data transmissions between or within one or more digital processing systems by identifying a data characteristic that is likely to change if there is an error in transmission. According to one embodiment, data messages are modified to achieve a selected characteristic according to a predetermined protocol, and changes to the data are recorded in a longitudinal check code (LCC) word, which is used by the receiver to decode the data message and restore the original data.

Claims

1. A method for checking the integrity of data transmission, the method comprising:

breaking, by a transmitter apparatus, a data message into a plurality of n-bit words;

grouping the n-bit words into word groups of (n−

m) n-bit words (where 0<

m<

n);

conditionally modifying the n-bit words to have a selected characteristic;

generating a longitudinal check code (LCC) word for a respective word group, which records characteristics of the n-bit words of the word group; and

adding the LCC word to the respective word group, resulting in word groups of (n−

m+1) words, whereby the n-bit words of the word groups of (n−

m+1) words may be analyzed together with the LCC word to check the integrity of the data transmission, and to restore the data message.

2. The method of claim 1, wherein an n-bit word is interpreted as having a sign, and modifying an n-bit word includes altering at least one bit from the n-bit word to achieve one of:

a selected value of the at least one bit;

a selected parity characteristic for the n-bit word; and

a selected sign of the n-bit word.

3. The method of claim 1, wherein the LCC word is generated by recording the occurrence of a change in each n-bit word of a word group in a corresponding bit of the LCC word.

4. The method of claim 3, wherein recording the occurrence of a change in an n-bit word includes recording whether at least one bit from the n-bit word is altered to achieve one of:

a selected value of the at least one bit;

a selected parity characteristic for the n-bit word; and

a selected sign of the n-bit word.

5. The method of claim 1, wherein the LCC word is generated by recording the original value of a bit from an n-bit word of a word group in a corresponding bit of the LCC word.

6. The method of claim 1, wherein the LCC word is generated by recording the original parity characteristic of an n-bit word of a word group in a corresponding bit of the LCC word.

7. The method of claim 1, wherein the LCC word is generated by recording the original sign of an n-bit word of a word group in a corresponding bit of the LCC word.

8. The method of claim 1, wherein an unused bit of the LCC word is modified to result in the LCC word having a selected characteristic.

9. The method of claim 1, wherein the LCC word is interpreted as having a sign, and at least one unused bit of the LCC word is modified to achieve one of:

a selected value of the at least one bit;

a selected parity characteristic of the LCC word; and

a selected sign characteristic of the LCC word.

10. The method of claim 1, wherein the n-bit words of a word group are conditionally modified to achieve a selected characteristic of the n-bit words, as defined by a predetermined protocol.

11. The method of claim 1, wherein the n-bit words of a word group are interpreted as having a sign, and the n-bit words of a word group are conditionally modified by altering at least one bit from each n-bit word to achieve one of:

a selected parity characteristic for each n-bit word, such that the parity characteristic of each successive n-bit word in the word group follows a predetermined protocol;

a selected value of the bit of the n-bit word, such that the selected value of the bit for each successive n-bit word in the word group follows a predetermined protocol; and

a selected sign of each n-bit word, such that the selected sign of each successive n-bit word in the word group follows a predetermined protocol.

12. The method of claim 1, wherein the LCC word is conditionally modified to achieve a selected characteristic of the LCC word, as defined by a predetermined protocol.

13. The method of claim 1, wherein the LCC word is interpreted as having a sign, and the LCC word is conditionally modified by altering an unused bit of the LCC word to achieve one of:

a selected value of the bit, as defined by a predetermined protocol;

a selected parity characteristic of the LCC word, as defined by a predetermined protocol; and

a selected sign characteristic of the LCC word, as defined by a predetermined protocol.

14. The method of claim 1, wherein the word group is transmitted to a receiving data buffer, comprising word positions containing original values.

15. The method of claim 14, wherein:

the n-bit words of a word group are conditionally modified to achieve a selected characteristic of the n-bit words, as defined by a predetermined protocol, and the predetermined protocol is used to ensure that the characteristics of the n-bit words in the word group are different from original values in the respective word positions of the receiving data buffer.

16. The method of claim 15, wherein:

the LCC word is conditionally modified to achieve a selected characteristic, as defined by a predetermined protocol; and

the predetermined protocol is used to ensure that the characteristics of the LCC word are different from original values in the respective word positions of the receiving data buffer.