In-band Full-duplex Technology Research Articles

Simultaneous-Multifunction Phased Arrays: Enabled by In-Band Full-Duplex Technology

Simultaneous-Multifunction Phased Arrays: Enabled by In-Band Full-Duplex Technology

Design and analysis of adaptive full-duplex cognitive relay cooperative strategy based on primary system behavior

The core problem of cognitive radio networks is the accurate sensing and the efficient use of spectrum holes without interfering the communication of the primary system. This paper proposes a cooperative strategy with two full-duplex cognitive base stations (FDCBS) where in-band full-duplex technology and cognitive radio are integrated. If the primary channel is in the “busy” state, the FDCBS assist the primary system in the retransmission of the failed packet and receive the cognitive packets simultaneously. We derive the outage probability and the average spectral efficiency of the primary system and the cognitive system for two scenarios where the 2-state Discrete Markov Chain describes the primary system behaviour (2-SDMC) and a non-identically distributed Nakagami-m fading channel is assumed. We determine the average spectral efficiency of the cognitive system in the case of incomplete self-interference, and the lower bound of the outage probability of the cognitive system when the primary channel is in the “busy” state. Numerical results show that our proposed scheme achieves a better improvement on the efficiency of the cognitive system and the primary system simultaneously than the traditional Half-Duplex relay mode.

Photonic-Enabled RF Canceller for Wideband In-Band Full-Duplex Wireless Systems

In-band full-duplex (IBFD) wireless systems offer the ability to revolutionize frequency spectrum utilization for future networks. This is only possible if the self-interference generated by each wireless node is sufficiently mitigated, and becomes more challenging as the bandwidth increases. RF cancellation is one of the critical components that enables this interference reduction, but has previously been limited to narrowband operation or restricted to distinctive environments. This paper presents a novel RF canceller that utilizes photonic components to create a wideband vector modulator architecture with tunable time-delay taps. A prototype system with 20 canceller taps has been demonstrated to provide 25 and 20 dB of cancellation over 500-MHz and 1-GHz instantaneous bandwidths, respectively, and is tunable between 0.5 and 5.5 GHz. This unique photonic-enabled RF canceller design provides a path forward to achieve the wideband operation and high tap counts that will be required to successfully deploy future wireless systems with IBFD technology.