Effects of Channel Estimation Error on Full-Duplex Two-Way Networks

Bidirectional communication systems based on full-duplex transmission have been proposed as a way to increase the ergodic capacity of multiantenna two-way networks. This type of system enables simultaneous exchange of data between two nodes via bidirectional use of spatial resources. However, when channel estimation error is present, each node experiences both desired-channel interference (DI) and echo-channel interference (EI). This paper investigates the effect of channel estimation errors on the ergodic capacities for bidirectional full-duplex transmission (BFD) using one of two combining schemes: maximal-ratio combining (MRC) or optimum combining (OC). We derive the ergodic capacities as closed-form expressions and quantify the effect of channel estimation errors on ergodic capacities for BFD with MRC (BFD-MRC) or OC (BFD-OC). Numerical results demonstrate that full-duplex transmission in two-way networks is an attractive option when channel estimation error is present.