Serially concatenated MSK with designed interleavers

The serial concatenation of an outer convolutional code, a designed interleaver and inner minimum shift keying (MSK) is presented. This system is compared to serially concatenated MSK with random interleaver and to a system with three outer convolutional codes and random interleaver, which is called woven coded MSK. It is shown analytically that serially concatenated MSK with designed interleaver achieves the largest free distance of the considered systems. Therefore, it has the best performance in the error floor region of the bit error rate curves, which is demonstrated in simulations.