Cross-channel similarity analysis and application using a multidimensional structural measure

To address the stringent requirements of full coverage and ultra-high data rates in next-generation mobile communications, it is essential to leverage the coexistence of multiple radio frequency (RF) systems operating in well-separated frequency bands within precisely defined scenarios. In this context, an investigation of frequency-dependent and environment-dependent channel characteristics by exploring the spatial and temporal correlations of multipath channels across different frequency bands and different environments is imperative. This paper introduces a structural Channel Similarity Index Measure (CSIM) that holistically evaluates multiple multipath parameters between two channels, including amplitude, phase, delay, angle of arrival (AoA) and angle of departure (AoD). Based on extensive field measurement campaigns and ray tracing simulations conducted across both centimeter wave (cmWave) and millimeter wave (mmWave) bands in typical indoor and outdoor scenarios, the proposed CSIM is proven to effectively measure similarity from specific dimensions as well as the statistical distributions, and the similarities between channels across different frequencies and different environments are presented. Moreover, the feasibility of out-of-band information-assisted beam search, enabled by cross-band channel similarity, is also validated.