Blockage detection and channel tracking in wideband mmWave MIMO systems

Tracking wideband millimeter wave (mmWave) multiple-input-multiple-output (MIMO) systems based on a hybrid architecture is a challenging problem, especially in high mobility scenarios where links are likely to be blocked by obstacles, such as trees, pedestrians or vehicles. In this paper, we propose a new strategy to track the frequency selective mmWave channel under blockage. We first introduce a statistical channel model that includes the evolution models for channel gains and angles of arrival and departure, as well as the statistics of blockage events. Then, we define a change point detection (CPD) test to identify the time instants where blockage appears/disappears, so the appropriate channel evolution models can be used for wideband channel tracking during the blockage events. To simultaneously achieve a high CPD success rate and a high accuracy in the channel estimate, we further propose a double digital combiner architecture that employs different digital combiners for CPD and channel tracking. Finally, we integrate into our framework a previously proposed Bayesian channel tracking algorithm. Simulation results show that the proposed approach achieves a good channel tracking performance even in mobile scenarios that suffer from highly dynamic blockage events.