Degrees of Freedom of Full-Duplex Cellular Networks with Reconfigurable Antennas at Base Station

TL;DR

This paper analyzes the degrees of freedom in full-duplex cellular networks with reconfigurable antennas at the base station, showing potential for doubling DoF and improving sum rate under various channel state information conditions.

Contribution

It provides a complete characterization of sum DoF for no CSIT and an achievable sum DoF for partial CSIT in FD networks with reconfigurable antennas, advancing understanding of FD capabilities.

Findings

FD base station with reconfigurable antennas can double the sum DoF.

Sum DoF is improved compared to traditional HD networks.

DoF gains translate into sum rate improvements at practical SNR levels.

Abstract

Full-duplex (FD) cellular networks are considered in which a FD base station (BS) simultaneously supports a set of half-duplex (HD) downlink (DL) users and a set of HD uplink (UL) users. The transmitter and the receiver of the BS are equipped with reconfigurable antennas, each of which can choose its transmit or receive mode from several preset modes. Under the no self-interference assumption arisen from FD operation at the BS, the sum degrees of freedom (DoF) of FD cellular networks is investigated for both no channel state information at the transmit side (CSIT) and partial CSIT. In particular, the sum DoF is completely characterized for no CSIT model and an achievable sum DoF is established for the partial CSIT model, which improves the sum DoF of the conventional HD cellular networks. For both no CSIT and partial CSIT models, the results show that the FD BS with reconfigurable antennas can double the sum DoF even in the presence of user-to-user interference as both the numbers of DL and UL users and preset modes increase. It is further demonstrated that such DoF improvement indeed yields the sum rate improvement at the finite and operational signal-to-noise ratio regime.