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B. P. Lathi, Zhi Ding - Modern Digital and Analog Communication Systems-Oxford University Press (2009)

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866 ERROR CORRECTING CODES

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PROBLEMS

14.1-1 Golay's (23, 12) codes are three-error correcting codes. Verify that n = 23 and k = 12 satisfies

the Hamming bound exactly for t = 3.

14.1-2 (a) Determine the Hamming bound for a ternary code (whose three code symbols are 0, I, 2).

(b) A ternary (11, 6) code exists that can correct up to two errors. Verify that this code satisfies

the Hamming bound exactly.

14.1-3 Confirm the possibility of a (18, 7) binary code that can correct up to three errors. Can this

code correct up to four errors?

14.2-1 If G and H are the generator and parity check matrices, respectively, then show that

14.2-2 Given a generator matrix

GH 1 =0

G = [I I ]

construct a (3, I) code. How many errors can this code correct? Find the codeword for data

vectors d = 0 and d = 1. Comment.

14.2-3

Repeat Prob. 14.2-2 for

G = (1 l ]

14.2-4

This gives a (5, 1) code.

A generator matrix

G=[ I 0 I 0 0 ]

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