Patent ID: 7330656

Claim:
A PON (Passive Optical Network) employing CDMA (Code Division Multiple Access) only in upstream transmissions, said PON comprising: a plurality of ONTs (Optical Network Terminals) corresponding to subscribers; a plurality of WDM filters for dividing upstream wavelengths to the PON and downstream wavelengths to the subscribers; an OLT (Optical Line Terminal) for receiving optical signals transmitted from the ONTs and transmitting the received optical signals to a higher network, said OLT transmitting signals transmitted from the higher network into at least one of the plurality of ONTs; and an optical coupler, wherein: each ONT includes a first switching unit connected to at least one lower interface, a level transformer for converting Ethernet signals having levels of ‘0’ and ‘1’ into data signals of levels of ‘−1’ and ‘+1’, a first code generator for generating CDMA codes as specific codes so as to discriminate each ONT, and a first multiplier for performing spread spectrum function by multiplying the data signals by the CDMA codes so as to transmit Ethernet signals transmitted from the lower interfaces into the higher network; and wherein the OLT includes an optical receiver for receiving optical signals transmitted wherein the OLT includes an optical receiver for receiving optical signals transmitted from the ONTs, a branching filter for branching upstream CDMA signals received through the optical receiver, a plurality of second code generators for generating codes for despread, a plurality of second multipliers for multiplying received signals by the codes generated from the second code generators, and a plurality of data decider for extracting data through correlation calculation, so as to transmit Ethernet signals transmitted from higher interfaces into the higher network.