A Complexity-Efficient High Resolution Propagation Parameter Estimation Algorithm for Ultra-Wideband Large-Scale Uniform Circular Array

Abstract

Millimeter wave (mm-wave) communication with large-scale antenna array configuration is seen as the key enabler of the next generation communication systems. Accurate knowledge of the mmwave propagation channels is fundamental and essential. In this contribution, a novel complexityefficient high resolution parameter estimation (HRPE) algorithm is proposed for the mm-wave channel with large-scale uniform circular array (UCA) applied. The proposed algorithm is able to obtain the high-resolution estimation results of the spherical channel propagation parameters. The prior channel information in the delay domain, i.e., the delay trajectories of individual propagation paths observed across the array elements, is exploited, by combining the high-resolution estimation principle and the phase mode excitation technique. Fast initializations, effective interference cancellations and reduced searching spaces achieved by the proposed schemes significantly decrease the algorithm complexity. Furthermore, the channel spatial non-stationarity across the array elements is considered for the first time in the literature for propagation parameter estimation, which is beneficial to obtain more realistic results as well as to decrease the complexity. A mm-wave measurement campaign at the frequency band of 28-30 GHz using a large-scale UCA is exploited to demonstrate and validate the proposed HRPE algorithm.X. Cai and W. Fan are with the APMS section at the Index terms-Millimeter-wave, ultra-wideband, large-scale uniform circular array, spatial nonstationarity and channel parameter estimation. I. INTRODUCTIONWhile the next generation communication system (5G) is still on its ascendant, millimeter wave (mm-wave) communication has been seen as the key enabling component due to the vast amount of available spectrum [1]-[3]. However, the air attenuation, small antenna aperture etc. would result in severe power loss [4] for the mm-wave propagations, compared to the sub-6 GHz frequency bands with rich multipath components (MPCs) [5]. Nevertheless, the mm-wavelength makes it practical to pack massive antennas [6] in a small area to form large scale antenna arrays. Beamforming [7] and beam-selection [2] techniques can be exploited to compensate the power loss and to enhance the spectrum efficiency through spatial multiplexing. Furthermore, applications such as localization, tracking and surrounding environment reconstruction [8] are promising, e.g., to help vision-disabled people.To enable the advanced 5G mm-wave techniques and applications, accurate and realistic channel models are fundamental and essential. The establishment of effective mm-wave channel models relies on the comprehensive channel measurements and the channel characteristics extracted from the measured data. In the mm-wave propagations with large scale antenna array configurations, the assumptions applied for the previous generation communication systems (e.g. the Long Term Evolution system) are violated. i) The narrowband assumption [9] is invalid due to the ultrawide system...

Fast Double-Directional Full Azimuth Sweep Channel Sounder Using Low-Cost COTS Beamforming RF Transceivers

“…It is based on a global coarse search for the maximum MPC finding. Thereafter, the second search was performed on a finer sub-grid to achieve (18) and (19) using the continuous functions of beam patterns and signal auto-correlation [8].…”

“…As described above, direction scanning requires a long measurement time (several hours per single channel acquisition) which is determined by the angular sampling interval (ASI) in a given scanning angle range of interest and the antenna's half-power beamwidth (HPBW) [13]. Moreover, a virtual synthetic array with low-gain antennas can be used [14]- [18] to capture the channel in an element space by physically moving a single antenna element along multiple positions to form a full array. However, this requires strict phase coherence to obtain the angle-resolved power spectrum by beamforming, as well as a very long measurement time.…”

Modeling Multi-Frequency Characteristics for Classroom and Hall Scenarios at 2-4, 9-11 and 27-29 GHz Bands

“…To establish an accurate and realistic channel model, comprehensive and complexity-efficient HRPE algorithms are required for extracting the spherical propagation parameters in ultra-wideband large-scale arrays for future communications. Furthermore, the realistic spatial non-stationarity in path gain across the array elements should be considered as well [26]. Therefore, based on the ultra-wideband and spherical wave propagation model assumption, the HRPE algorithm [26] is exploited to fully extract the spherical channel propagation parameters, i.e.…”

“…Suitable number of paths assuming for each frequency band is necessary to obtain accurate estimation results. Moreover, spatial non-stationarity in realistic channel, such as the power variation across the antenna elements should also be considered [26]. Therefore, to fully and realistically extract the parameters of the MPCs, a complexity-efficient high resolution parameter estimation (HRPE) algorithm is needed.…”

“…• A complexity-efficient high-resolution parameter estimation (HRPE) algorithm [26] is utilized for fully extracting spherical channel propagation parameters of the MPCs with the spatial non-stationarity of path gain considered, resulting in more accurate and realistic estimation. Besides that, based on the HRPE estimation results, composite level parameters, such as path loss, number of paths, RMS delay spreads and azimuth spreads at 2-4, 9-11 and 27-29 GHz frequency bands are investigated.…”