code division multiple access

An effective solution to deal with the frequency selectivity of communication channels in the last decade is the use of multicarrier systems. One of the multicarrier systems that has received much attention in recent years is the generalized frequency division multiplex (GFDM). Due to the use of a well-localized prototype filter and also a short CP length, GFDM achieves excellent performance at an acceptable rate in communication channels with frequency selectivity and severe time variations. On the other hand, one way to achieve frequency diversity and prevent interference in multiuser systems is to use the code division multiple access (CDMA) technique. In this paper, a new data transmission system is proposed based on the combination of GFDM and CDMA in a multiuser network. A new structure for the transmitter and receiver of the proposed multi-user CDMA-GFDM system is presented in uplink and downlink. The results of the simulations show that the proposed system overcomes the conventional GFDM system in terms of bit error rate (BER) and achieves much better performance. In the simulations, we will see that in the Pedestrian A Profile Delay Power (PDP) communication channel, for SNRs of 10 and 20 dB, about 1.6 and 80 times BER improvement is achieved compared to GFDM, respectively. Also, for the Pedestrian B channel at the same SNRs, it will have at least 1.6 and 130 times BER reduction, respectively.