On Time-Interleaving Errors in Beamforming Receivers

Time-interleaved ADCs are a key building block in mm-wave receivers, where the use of multi-GHz signal bandwidths requires high-performance wide-band data conversion. It is therefore necessary to explore the beamforming receiver system impact of different time-interleaved ADC parameters and limitations, such as number of interleaved channels, mismatches between channels, non-idealities of the subADCs, and correlation between sub-ADCs. This paper presents a scalable testbench in MATLAB/Simulink which models time-interleaved pipeline ADCs with high fidelity. The testbench is used to investigate the impact of time-interleaving errors on digital, hybrid, and analog beamforming receivers, both with and without interfering signals. Results show that the combination of time-interleaving errors and interference causes a degradation in beamforming performance, even at relatively low SNDR levels. The effect is more pronounced in digital beamforming compared to hybrid and analog beamforming.