Telephony over passive optical network using a TDMA/CDMA hybrid scheme

摘要

In this paper the concept of improving present TPON schemes to accommodate more users is investigated by the employment of a Time Division Multiple Access/Code Division Multiple Access (TDMA/CDMA) hybrid scheme. The hybrid strategy gives a 50:1 improvement in user capacity on TDMA. This is achieved because less power is used by the laser source to deliver data down the fibre to each user thus allowing more users on TPON. Moreover it eliminates the need for the addition of extra wavelength sources and power increase as is the case in present TPON techniques. The results of an analytical model are presented which show how such a system would affect present TDMA on TPON and hybrid TDMA/CDMA in terms of Bit Error Rate (BER), Signal to noise ratio (SNR) and the launch power needed by a laser source.