Beam-based uplink multi-user detection for mmWave communications

To keep up with the dramatic proliferation of mobile traffic, the fifth-generation (5G) systems adopt the millimetre-wave (mmWave) frequency band together with a large-scale antenna array. Although the use of large-scale antenna array can effectively solve the problem of severe signal attenuation at high frequencies, it also derives other issues. For example, the system complexity on spatial domain becomes computationally prohibitive, because the system has to estimate all the channels of each antenna. Also, the ever-growing data rates make the frequency selectivity of channels worst in the spatial domain. Recently, utilising the sparse characteristics of the mmWave band, beam-domain signal processing has drawn increasing interest for future 5G systems. In this study, the authors design multi-user data detection for the mmWave communication on beam domain. To effectively reduce the design complexity, they exploit the salient feature of channel sparsity to propose beam-channel selection and user grouping. Results indicate that the beam-channel selection is a critical step in the design of 5G systems since it can significantly decrease the complexity while maintaining the throughput. User grouping allows us to independently design detectors with lower complexity. Results show that the designed detectors can achieve a good trade-off between throughput and complexity.