Multi-rate and multi-quality transmission scheme using adaptive overlapping pulse-position modulator and power controller in optical cdma networks

We propose the multi-rate and multi-quality transmission scheme using adaptive overlapping pulse-position modulator (OPPM) and optical power controller in optical CDMA networks. In the proposed system, the multi-rate and the multi-quality transmission can be achieved by accommodating users with the different value of M and the different transmitted power in the same network. The proposed scheme has the advantage that it is not required to change the code-length and weight depending on the required bit-rate of the user and the difference of the bit-rates does not have so much effect on the bit error probabilities(BEPs). Moreover, the difference of the power does not cause the change of bit-rate. We analyze the BEPs of the four multimedia service classes corresponding to the combinations of high/low-rates and high/low-qualities, and show that the proposed scheme can easily achieve distinct differentiation of the service classes with the simple system configuration.