In-band full duplex cellular operation with reconfigurable uplink antennas at base station

In this paper, we propose an in-band full duplex (IBFD) cellular operation with reconfigurable uplink (UL) antennas at base station (BS). For handling mobile station (MS)-to-MS interference in an IBFD cellular system, a repetition coding of UL MSs is considered. While the repetition coding of UL MSs is applied, downlink (DL) MSs can cancel MS-to-MS interference by using one silent symbol to measure MS-to-MS interference. To avoid UL system throughput loss due to the repetition coding of UL MSs, we propose using reconfigurable antennas to enable to serve more UL users simultaneously than the number of UL antennas. The proposed scheme does not require any MS-to-MS channel estimation or channel information feedback, as well as any interference cancellation receiver at the DL MSs. We analyze the degrees of freedom (DoF) gain of the proposed scheme. It is shown that the proposed scheme achieves the double DoF gain compared with half duplex scheme when the number of UL MSs and the preset modes of reconfigurable antennas go infinity. Numerical results show that the proposed scheme has a significant sum rate performance gain even though the number of UL MSs and the number of preset modes of reconfigurable antennas do not go infinity.