An MPSK Millimeter-Wave Point-to-Point Link With Radio Over Fiber Synchronous Baseband Receiver

This paper reveals a millimeter-wave point-to-point radio link of MPSK (QPSK, 8-PSK, and 16-PSK) modulation without the need of an analog to digital converter (ADC). The proposed point-to-point radio link uses the clock and data recovery (CDR) applied in the optical-electrical converter (OEC) to recover the MPSK intermediate frequency (IF) signals frequency offset as well as the radio over fiber (RoF) concept to extend the transmit distance of the central unit and the remote radio unit. The proposed point-to-point synchronous radio link removes the high-speed ADC requirement for the digital-intermediate-frequency-over-fiber (DIFoF) link, which can significantly reduce the complexity and the expense of the remote radio unit compared with the standard RoF link. Simultaneously, we have designed a simple symbol synchronization algorithm to realize the real-time point-to-point radio link on a Field Programmable Gate Array (FPGA). The proposed millimeter-wave radio link has successfully demonstrated 6 Gbps QPSK transmission and can tolerate a frequency offset up to 100 MHz.