“…However, FIGURE 8. Comparison of beam measurements overhead of the multi-codebook-based [39], [44], [45], [71] and subspace-reduction-based [40], [41], [43], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [68], [69], [73], [74], [75], [76], [77], [79], [80], [81] surveyed works against exhaustive beam sweeping. The number of UE beams is fixed to N = 16.…”