Performance comparison of different multiple access schemes for the downlink of an OFDM communication system

A comparison of different multiple access schemes for the downlink of an OFDM communication system is performed. The access methods OFDM-TDMA, OFDM-FDMA, and OFDM-CDMA are described and compared with regard to flexibility and computation complexity. Further on, the performance of the different approaches is quantitatively analysed, comparing the resulting BER for the given OFDM system in a time-variant and frequency-selective radio channel.