Question

The minimum end to end delay in block interleaving is

(a) 2MN+2M+2

(b) 2MN-2M+2

(c) 2MN-2M-2

(d) 2MN+2M-2

This question was addressed to me in an interview for job.

The question is from Concatenated and Interleaving Codes and its Application in CD topic in portion Channel Coding of Digital Communications

Answer 1

The correct option is (b) 2MN-2M+2

For explanation I would say: The inter leaver or De-inter leaver delay is 2MN symbol times. M(N-1)+1  memory cells needs to be filled before transmission can begin. Thus the minimum end to end delay is 2MN-2M+2 symbol times, not including any channel propagation delay.