LDPC BASED MULTI-USER SPACE FREQUENCY DIVERSITY SYSTEM DESIGN FOR UPLINK MULTI-CARRIER CDMA

We present the performance of a multi-user detector for space frequency uplink transmission in multi­ carrier CDMA systems. In our proposed architecture, the data symbols are parallelized and then each of the symbols are spread by a spreading code before sending the chips as multiple OFDM codeword. The SFBC decoder is placed at the last stage of our multi-user receiver and the user separation is done after the OFDM demodulator. We show that, the system is particularly easy to implement, and besides, the performance is comparable to the case of a single user SFBC system. We also point out the need of additional interleaver when the system is used with a LDPC channel encoder.