A new coded optical code division multiple access (OCDMA) systems

The performance of optical code division multiple access with pulse position modulation system (OCDMA-PPM) considering the effects of using recent kinds of coding schemes is analyzed and discussed. It is seen that coding offers considerable coding gain, but with reasonable encoding/decoding complexity and is very effective in increasing the numbers of simultaneous users at certain bit error probability. In this paper we obtain upper bounds to average maximum likelihood (ML) bit error probability of optical CDMA-PPM with some coding schemes such as serial concatenated block code (SCBC), double serial concatenated block code (DSCBC), the much interesting code (turbo code) and the most recent promising structured code (zigzag code) which have very low complexity softin/softout decoding rules, also have lower error floors than comparable turbo codes and double concatenated codes.