Multi-length time-and-frequency-hopping codes for multimedia service differentiation

In this paper, we propose a new generation algorithm of multi-length time-and-frequency-hopping codes for the optical code-division multiple access network. The generation algorithm is more flexible compared to the conventional multi-length code generation algorithms, and thus can provide more sophisticated multimedia service differentiation with respect both to the transmission rate and bit error rate (BER). As a way to differentiate the multi-length codes for multiple service classes, we show that the ratio of the BER performance between any two service classes can be approximated by the ratio of the code weights independent of code lengths under high user population. We also present the performance results under various conditions to demonstrate the differentiation of services classes with respect to BER and packet delay.