A multi-carrier based approach to wireless duplex: Orthogonal frequency division duplex (OFDD)

One of the advantages of multi-carrier transmission techniques is the flexibility of frequency resource usage. In this paper, we focus on this advantage and extend it to a wireless duplex scheme. This proposed scheme is named orthogonal frequency division duplex (OFDD). In OFDD, uplink and downlink channels consist of different sets of orthogonal sub-carriers each other. Terminals transmit their own signals simultaneously, and thus OFDD realizes full-duplex wireless systems. In this paper, we introduce the principle of OFDD and compare the features of OFDD and the other conventional duplex schemes. In addition, we refer to one of the significant issues caused by the loss of the orthogonality between the uplink and downlink, which is named as inter-link interference. We evaluate the bit error rate performance of point-to-point OFDD wireless communications in the presence of inter-link interference by computer simulations.