Throughput and mode selection in two-way MIMO systems under queuing constraints

In this paper, the throughput of and mode selection between half-duplex and full-duplex modes are studied in two-way multiple-input multiple-output (MIMO) systems operating under statistical queuing constraints. In particular, the effective capacity of these systems is determined in order to identify the throughput under constraints on the buffer overflow probability. In the low signal-to-noise ratio (SNR) regime, the optimal input covariance matrices that achieve the minimum energy per bit of the system are investigated. Full-duplex mode is found to have better performance at low SNRs and short distances, while half-duplex mode outperforms full-duplex operation at high SNR levels and long distances. Additionally, in the numerical results, the influence of the self-interference cancelation parameter and QoS exponent on the throughput is analyzed.