31-05-2012, 01:34 PM
Error Detection and Correction
Error Detection.ppt (Size: 1.28 MB / Downloads: 29)
INTRODUCTION
Let us first discuss some issues related, directly or indirectly, to error detection and correction.
BLOCK CODING
In block coding, we divide our message into blocks, each of k bits, called datawords. We add r redundant bits to each block to make the length n = k + r. The resulting n-bit blocks are called codewords.
LINEAR BLOCK CODES
Almost all block codes used today belong to a subset called linear block codes. A linear block code is a code in which the exclusive OR (addition modulo-2) of two valid codewords creates another valid codeword.
CHECKSUM
The last error detection method we discuss here is called the checksum. The checksum is used in the Internet by several protocols although not at the data link layer. However, we briefly discuss it here to complete our discussion on error checking.
Error Detection.ppt (Size: 1.28 MB / Downloads: 29)
INTRODUCTION
Let us first discuss some issues related, directly or indirectly, to error detection and correction.
BLOCK CODING
In block coding, we divide our message into blocks, each of k bits, called datawords. We add r redundant bits to each block to make the length n = k + r. The resulting n-bit blocks are called codewords.
LINEAR BLOCK CODES
Almost all block codes used today belong to a subset called linear block codes. A linear block code is a code in which the exclusive OR (addition modulo-2) of two valid codewords creates another valid codeword.
CHECKSUM
The last error detection method we discuss here is called the checksum. The checksum is used in the Internet by several protocols although not at the data link layer. However, we briefly discuss it here to complete our discussion on error checking.