CHANNEL CODING FOR ASYNCHRONOUS FIBEROPTIC CDMA COMMUNICATIONS

Several recent studies have explored the feasibility and systems perfo rmance aspects of a code division multiple access (CDMA) format for fi beroptic networks [1]-[13], Previously discussed CDMA architectures wo uld either have to tolerate a high bit error rate or be forced to use long code sequences in networks with even a moderate number of simulta neous users. The use of long sequences lowers the maximum achievable b it rate or places unrealistic requirements on the system hardware. Thi s paper examines some of the possible improvements to system performan ce that could be realized by combining the CDMA format with external e rror correcting codes (ECC's) or a PPM format, It is determined that E CC's can be highly effective in lowering the BER, and/or increasing th e achievable information bit rate and number of network users, The res ults are sufficiently encouraging to conclude that one should seriousl y consider including ECC's in any practical fiberoptic CDMA network.