A new hybrid division duplex scheme: Orthogonal frequency division duplex (OFDD)

In this paper, we propose orthogonal frequency division duplex (OFDD) which combines orthogonal division duplex (ODD) [1] and frequency division duplex (FDD) as a new hybrid division duplex scheme. In the asymmetric traffic environment, the mismatch of uplink and downlink between adjacent cells results in co-channel interference (CCI) which degrades the system performance. The proposed scheme can remove CCI of users at cell boundary by cell-partitioning. Furthermore, it can additionally reduce CCI of users at cell center by random sub-carrier allocation in ODD mode. From simulation results, we show that OFDD enhances average cell capacity by reducing CCI in the asymmetric traffic environment, compared with conventional schemes.