A 40gbps DQPSK Modem For THz-wave Point To Point Communications

With the mobile network gaining its popularity nowadays, the demand of network capacity is increasing dramatically. Utilizing wider bandwidth is a straightforward way of improving capacity. Millimeter-wave(mm-wave) frequency bands, given tens of GHz available bandwidth, offer opportunities to realize multi-gigabit wireless transmission. A high speed differential quadrature phase shift keying(DQPSK) modulator and demodulator(modem) is presented for data rates up to 40 Gbps, in which the modulator is based on an FPGA and the demodulator is implemented using microwave components. The modem performance has been verified in a lab environment. This work demonstrated that millimeter-wave wireless communication is a flexible alternative to optical fiber links in next generation high capacity networks.This thesis mainly studies the design and implementation of the 40 Gbps DQPSK modem. Firstly, the thesis presents the motivation of high speed communication research and lasted research results in the field. Secondly, the thesis proposes a new differential coding scheme and its FPGA implementation structure. Techniques of improving signal integrity are also discussed such as pre-emphasis. Next, a differential demodulator structure build by microwave components is demonstrated. Finally, measurement setup and results are presented and discussed that verifies this modem can operate up to 40 Gbps data rate.