Question

How many redundant bits are added in block codes for k information bits and n code bits?

(a) n+k

(b) n-k

(c) k^2

(d) n^2

The question was asked at a job interview.

My question is from Block Codes and Finite Fields topic in chapter Equalization, Diversity and Channel Coding of Wireless/Mobile

Answer 1

Right option is (b) n-k

The explanation is: In block encoder, k information bits are encoded into n code bits. A total of n-k redundant bits are added to the k information bits for the purpose of detecting and correcting errors.