Self-Interference Mitigation using 1-Bit Bandpass Delta-Sigma Modulator with No Output Section

Abstract

In wireless communication systems, multi-input and multi-output (MIMO) and carrier aggregation (CA) have been developed to achieve high speed and high capacity communication. In these methods, many transmitters and receivers are used, which leads to larger equipment, and miniaturization is an issue. In this paper, a 1-bit bandpass delta-sigma modulator (BP-DSM) for the transmitter and a direct RF undersampling sample/hold integrated circuit (S/H-IC) for the receiver are introduced. In addition, to mitigate the self-interference between transmitters and receivers caused by miniaturization, the output waveform of the transmitted signal is pulsed like Return to Zero (RZ) and a no output section (NOS) of the transmitted signal is periodically introduced to be separated the received signal in the time domain. In a demonstration experiment, a reception performance of 9.87% error vector magnitude (EVM) in the NOS has been achieved at 760 MHz for both the transmission frequency and reception frequency, 64 QAM and 16 QAM for the transmission and reception signal, respectively, and a DU ratio of 0 dB.