Comparison and Modeling of Multi-Frequency Wideband Channels at Sub-6 GHz Bands

Developing multi-frequency cooperation algorithms in wireless communication systems has been a topic of interest since the ever-growing complexity and network density prompt the current system to work at multiple frequencies. In this paper, firstly a wideband multiple-input and multiple-output (MIMO) channel model capable of reflecting characteristics in multi-frequency systems is presented, in which channel impulse response is given, and then large-scale and small-scale channel model parameters are investigated for their frequency dependence. In order to gain deeper insight into the behaviors of channels with different sub-6 GHz bands, a simulation setup is established, which compares multiple channel properties at widely available frequencies, namely 2.4, 3.5, and 5 GHz. Statistical properties such as time auto correlation function (ACF), and frequency correlation function (FCF) of the same frequency, spatial correlation coefficients between different frequencies, as well as instantaneous delay power spectrum density (PSD)) are among the metrics to be compared. Analysis of the comparisons offers insightful discoveries about channel characteristics. After justifying the presented multi-frequency channel model with data from measurement results, it is concluded that the model can be used to develop and evaluate multi-frequency communication protocols and systems.