Near-field Ultra-wideband mmWave Channel Characterization Using Successive Cancellation Beamspace UCA Algorithm

Of the wide palette of 5G features, ultra-wide bandwidth and large-scale antenna configuration are regarded as the essential enabling technology components at millimeter wave (mmWave) communication. Accurate knowledge of delay and angle information of multipath components is essential for many applications in mmWave systems. There is a strong need for a low computation-cost channel estimation algorithm for such systems, where typically adopted far-field and narrowband assumptions might be violated. In this work, a generic yet novel beamspace uniform circular array (UCA) beamforming algorithm with successive cancellation scheme is proposed to jointly detect the impinging angle and delay of the multipath components. The proposed algorithm is computationally cheap and it works for ultra-wideband (UWB) systems in the near-field conditions. Both numerical simulations and experimental validation results are provided to demonstrate the effectiveness and robustness of the proposed algorithm, compared to the state-of-art works

Measurement-based Channel Characterization Using Virtual Array with Directional Antenna

Obtaining accurate channel characteristics is essential for wireless communication system design and protocols. Directional scan sounding (DSS) achieved by rotating a directional antenna with a turntable, and virtual antenna array (VAA) basedsounding achieved by moving the antenna to the pre-designed locations are both popular methods to characterize static radio channel environments. However, the beam-width of the employed directional antenna limits the angular resolution of DSS. The conventional VAA usually employs an omnidirectional antenna which limits its application in millimeter wave bands due to the low antenna gain. In this work, VAA scheme based on directional antennas is presented to characterize the spatial-temporal profiles and omnidirectional pathloss of the channels. This scheme can provide high angular resolution and improve the SNR in the measurements simultaneously. Indoor channel measurements at 28 GHz with four different link distances were conducted to verify the effectiveness of the directional antenna based VAA scheme