Full-duplex bidirectional communication under self-interference

Abstract

In this paper, we analyze bidirectional communication between two multiple antenna nodes performing half-duplex and full-duplex transmissions. We compare the performance of half-duplex and full-duplex modes in terms of achievable sum rate under finite Signal to Noise Ratio (SNR), while utilizing a realistic, experimentally characterized residual self-interference (SI) model for full-duplex operation. In our comparisons, for considering different perspectives for radio resource exploitation, we evaluate the antenna conserved and RF chain conserved full-duplex implementations, while investigating the effect of the number of antennas, different SI cancellation levels and transmission power. Our results indicate that antenna conserved full-duplex is only slightly better than half-duplex transmission, even when SI is completely canceled. RF chain conserved full-duplex, on the other hand, can double the half-duplex performance when SI is perfectly canceled, and still significantly higher capacity over half-duplex is achieved by realistic SI cancellation. Specifically, the capacity gain of RF chain conserved full-duplex over half-duplex is highly dependent on the transmission power levels, but not dependent at all on the number of antennas. Lastly, it is also deduced that individual transmission power of nodes is also important in determining the sum rate, especially for full-duplex implementations with poor SI cancellation.