Patent ID: 7035201

Claim:
A method for multiplexing and multiple accessing a multi-rate OFDM-CDMA system with an input data stream having a data rate of a predetermined value m, said m being a multiple of a basic rate and said multi-rate OFDM-CDMA system having a plurality of predetermined spreading codes and a plurality of orthogonal carrier, said input data stream having a selected number of data being m×P wherein P is an integer, and each data representing a symbol having a predetermined sample duration, said method comprising the steps of: (a1) multiplexing said input data stream into m effective data sub-streams each having a data rate equal to said basic rate and having P data; (a2) performing an OFDM operation on each of said m effective data sub-streams, wherein said OFDM operation comprising: (b1) serial-to-parallel converting each of said m data sub-streams into P parallel data in each sub-stream; and (b2) copying said representative symbol of each data into F branches indicating from a first branch to a F th branch, wherein F is an integer and a constant spreading factor of said plurality of spreading codes; and (a3) performing a CDMA operation on each of said P×F wherein F is a spreading factor of a basic data-rate user, and an integer effective data sub-streams being performed with OFDM operation.