Parallel Channel Sounder for MIMO Channel Measurements

In order to address the challenges in MIMO channel measurement and modeling for 5G communication scenarios, a CDM-based parallel channel sounder is developed and evaluated in this article. Compared to traditional TDM-based channel sounders, our parallel channel sounder supports eight-by-eight (8 x 8) MIMO communications, 200 MHz RF bandwidth, 5 ns multipath time resolution, 36 dB dynamic range, and 2 kHz maximum Doppler shift at a speed of 350 km/h. To achieve these performance targets, a series of sophisticated technical solutions are proposed and analyzed to realize 32 ps synchronization accuracy, 51.36 Gb/s parallel data streaming, and high-precision calibration across multiple channels. Key functions and performance metrics are evaluated and verified in a microwave chamber. Real measurement results in a complex campus environment show that our CDM-based parallel channel sounder can capture more detailed channel characteristics, and therefore offer accurate PDPs and RMS delay spreads at both LoS and NLoS positions under MIMO communication scenarios.