Wideband self-interference channel modelling for an on-frequency repeater

In-band full-duplex relaying has been of recent interest as it can potentially double spectral efficiency and decrease latency, thus improving throughput to the end user. The bottleneck in enabling full-duplex operation is the self-interference (SI) due to the relay's own transmission, which must be mitigated at the antenna, radio frequency and digital domains. In the case of compact back-to-back relays which are proposed for outdoor-to-indoor relaying, the SI comprises direct coupling and multipath components. This paper models the SI channel across 300MHz bandwidth at 2.6GHz in two indoor environments with a back-to-back relay antenna. The power delay profile of the SI channel is modelled as a single decaying exponential function with specular components represented by delta functions. The fading characteristics of each tap are modelled by a normal distribution based on the measurements. The proposed model can be used to generate a tapped-delay model of the SI channel between compact back-to-back antennas for use in link-level simulations and hardware in the loop emulation.