Wideband channel tracking for mmWave MIMO system with hybrid beamforming architecture: (Invited Paper)

Millimeter-wave (mmWave) systems require a large number of antennas at both base station (BS) and user equipment (UE) for a desirable link budget. Due to time varying channel under UE mobility, up-to-date channel state information (CSI) is important to obtain the beamforming gain. The overhead cost of frequent channel estimation becomes a bottleneck to achieve high throughput. In this paper, we propose the first mmWave frequency selective channel tracking technique for hybrid analog and digital beamforming architecture. During tracking, this technique exploits mmWave channel sparsity and uses only one training symbol to update the CSI. Our simulation study utilizes a dynamic channel simulator that builds on top of recently proposed geometric stochastic approach from mmMAGIC project at 28 GHz. Assuming 10m/s moving speed and 200 deg/s rotation speed at UE, the proposed algorithm maintains the 80% of the spectral efficiency as compared to static environment over a time window of 100 ms. The proposed tracking algorithm reduces the overhead by 3 times as compared to existing channel estimation technique.