Testing of wireless communication systems under realistic propagation conditions is critical to ensure that the specified performance is achieved in the target deployment scenarios. To this end, accurate characterization of radio channels via channel sounding and the high-fidelity replay thereof by emulation in the laboratory is fundamental for this purpose. In this thesis, contributions are made to three key areas to address this challenge.

First, a long-range phase-coherent channel sounder based on the vector network analyser (VNA) is developed.

Second, channel measurement and characterization are carried out employing the developed channel sounder to gain insight into path trajectory evolution in the propagation scenario.

Third, a framework for high-fidelity channel emulation in the presence of hardware resource constraints is proposed.

More specifically, a phase compensation scheme is proposed to mitigate the phase instability of optical fiber based VNA channel sounders, thus making large-scale, long-range phase-coherent channel sounding possible. With the proposed VNA-based channel sounder, long-range and phase coherent channel measurements in the millimeter wave (mmWave) frequency band using virtual antenna arrays are carried out thus enabling the characterization of the radio channel with high spatial and delay resolution.

Furthermore, the proposed channel sounder is employed in the characterization of the birth and death of
multipath components (MPCs) in indoor channels which is fundamental for the development of spatially consistent channel models.

One main application of radio channel models is for end to end testing in the laboratory. However, measured data from channel sounders or ray tracing simulation cannot be directly used in radio channel emulators due to the limitation of hardware resources on the radio channel emulators i.e. a limited number of delay taps and a fixed delay grid. To address these two challenges, a framework for pre-processing measured or simulated channels for replay in file-based digital channel emulators is proposed.