ON DESIGN CONCEPT FOR FULL-DUPLEX BASED FLEXIBLE RADIO TRANSCEIVERS

Overview & Synopsis

The wireless medium is a shared and limited resource. Current wireless standards always share the medium with Half-Duplex principle: the transmission and reception of signals are done in two separate time slots or two different frequency bands. Besides, the transceiver can only transmit and receive one signal at a time. This dissertation takes an alternate approach: Instead of sharing the medium with Half-Duplex principle, the entire licensed frequency band is shared for simultaneous transmission and reception, which we call Full-Duplex. Besides, the design concept for a wideband flexible radio transceiver can process two different types of signals at a time. To reach this goal, we propose to use an active analog radio frequency (RF) selfinterference cancellation (AARFSIC) method or a combination scheme of the AARFSIC and active digital self-interference cancellation in time domain (ADSICT) to cancel the strong self-interference (SI) induced by the Full-Duplex principle. Based on the Full-Duplex radio, we propose a flexible Full-Duplex Dual-Band (FDDB) OFDM radio transceiver by combining the Dual-Band RF front-end. Building on these, we make three main contributions: We present an active selfinterference cancellation (ASIC) scheme, which can cancel both the strong one-path and multi-path SI completely, based on the combination of the AARFSIC and DSICT. Next, we introduce the design and evaluation of a Full-Duplex OFDM radio, including analysis and qualification of the impact of the thermal noise and phase noise on the system performance. Finally, we develop an FDDB OFDM radio that can work on two separate spectrum fragments. In order to eliminate the impact of the I/Q imbalance on the FDDB radio, a simple but practical digital I/Q imbalance estimation and compensation method is presented. The system level simulation conducted with ADS and Matlab software shows that this method can efficiently compensate both high and low I/Q imbalance.