Example 7.3

A mobile radio data link uses interleaving to spread the data errors on reception. If the interleaving depth used is a 10 x 8 matrix, and the bit rate for the signal is 9600 bps, what is the latency introduced by the interleaving process?

Solution

The de-interleaving process requires that the matrix rows are full up before the data can be read out from the columns, thus 8 x 10 bits = 80 bits must be read into the matrix before the de-interleaved data can be extracted. The data rate is 9600 bps, thus the time taken to load the matrix is 80 / 9600 = 8.3  ms. A further 8.3 ms will be used loading the interleaving matrix in the transmitter, giving a total latency of 16.6 ms.