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The objective of this paper is to describe a least square method to compute the far field from a nonuniformly spaced antenna array. This is because the far field pattern of an antenna array is the Fourier transform of the current distribution developed on the antenna structure, This is equivalent to computing the spectrum from a nonuniformly spaced data set using a least squares method. The merit...
The radio holography method performs the direction-of-arrival (DOA) estimation of radio waves with a relatively simple array system because it uses a reference antenna. This paper proposes a new radio holography method in which cyclic correlations of digital-modulation signals are introduced for the DOA estimation of desired signals only. The DOA estimation accuracy of the method is evaluated by computer...
The maximum likelihood (ML) estimation for multipath component (MPC) parameters requires high computational complexity, resulting in low efficiency in channel measurement campaigns. In this paper, a new method, called Fast Reduced-Dimension SAGE (FRDS) algorithm, is proposed to estimate the parameters such as excess delay, power, and angle-of-arrival/departure (AoA/AoD). By sounding channels using...
The Over-The-Horizon (OTH) locating of radiation source can be realized by the troposcatter propagation of electromagnetic (EM) signals. This paper studies the troposcatter signal group delay for target ranging and proposes a modified beamspace MUSIC to estimate the arrival azimuth angle of the troposcatter signal. Finally, the OTH target can be located by the ranging and azimuth angle estimation...
In this paper, we describe a modified signal design for Multistream Spatial Modulation (MSM). The fundamental idea behind MSM is to activate multiple antennas and transmit complex symbols along with active antenna indices. Here, a modified MSM technique explicitly designed to combat the effect of spatial correlation in realistic channel scenarios is proposed. In this MSM scheme, two antennas are made...
Co-prime arrays have gained in popularity as an efficient way to estimate second order statistics at the Nyquist rate from sub-Nyquist samples without any sparsity constraint. We derive an expression for the degrees of freedom and the number of consecutive values in the difference set for the prototype co-prime array. This work shows that, under the wide sense stationarity (WSS) condition, larger...
In this paper, we propose a joint analog-digital (AD) beamforming scheme that exploits the mutual coupling effect to further improve the performance of multi-user multiple-input single-output (MU-MISO) systems. We firstly propose a joint AD scheme by iteratively optimizing the beamforming vectors in the digital domain and the load impedances of each antenna element in the analog domain. We further...
In this paper, three-dimensional (3D) regular-shaped geometry-based stochastic model (RS-GBSM) is developed for wideband multiple-input multiple- output (MIMO) high speed railway communication system under non-isotropic scattering condition. Correlations of the proposed model in space, time and frequency are studied. Numerical result shows that the simulation model fits the reference model well.
A small-cell network (SCN) constructed by splitting a macro-cell into numerous small cells using an active antenna array system is studied. A synchronization signal appropriate for the SCN, virtually generated by a base station (BS) with 3D beamforming, is proposed for efficient handover in SCNs. The virtual cell synchronization signal (VCSS) carries a macro-cell ID (MCID) and virtual- cell ID (VCID)...
Recently, the use of unmanned aerial vehicle (UAV) is going to receive great interest in various areas. As a newly emerging area, UAV-aided communications encounter unique communication scenarios and thus need corresponding UAV channel models for better design of such UAV communication systems. In this paper, we propose a three-dimensional (3D) sphere UAV air-to-ground (A2G) multiple-input-multiple-output...
Beamforming design for millimeter-Wave hybrid array with the subarray structure is very challenging. There is neither known optimal solution that maximizes the sum rate capacity nor near-optimal solution. This paper proposes some low-complexity user-directed analog radio- frequency (RF) beamforming design schemes. The basic idea is to iteratively allocate different subarrays to different users such...
Massive multiple-input multiple-output (Massive MIMO) is acknowledged as a key technology for the 5th generation (5G) of wireless communication systems, which theoretically proved to be of higher throughput, better robustness, superior spectrum- and energy- efficiency. A reliable and realistic channel model serves is the enabling foundation for practical design and testing of communication systems...
In this paper, we propose a joint analog-digital (A/D) beamforming scheme for the point-to-point (P2P) multiple-input-multiple-output (MIMO) systems, where we exploit the mutual coupling effect to further improve the system performance. By judiciously selecting the value of each load impedance for the antenna array, it will be shown that the mutual coupling effect can be beneficial. We firstly prove...
Closed-form approximations to the expected perterminal signal-to-interference-plus-noise-ratio (SINR) and ergodic sum spectral efficiency of a large multiuser multiple-input multiple-output system are presented. Our analysis assumes correlated Ricean fading with maximum ratio combining on the uplink, where the base station (BS) is equipped with a uniform linear array (ULA) with physical size restrictions...
We propose a hybrid architecture to integrate RF (i.e., sub-6 GHz) and millimeter wave (mmWave) interfaces for 5G cellular systems. To alleviate the challenges associated with mmWave communications, our proposed architecture integrates the RF and mmWave interfaces for beamforming and data transfer, and exploits the spatio-temporal correlations between the interfaces. Based on extensive experimentation...
In this paper, the mutual coupling effect among antenna elements for the downlink multiuser multiple-input-single-output (MU-MISO) is studied. Different from conventional knowledge that the mutual coupling effect usually degrades the system performance, a joint analog-digital precoding scheme is proposed so that the system can benefit from this effect. Linear precoding approaches are applied in the...
Compressed beam-selection (CBS) exploits the limited scattering of the millimeter wave (mmWave) channel using compressed sensing and finds the best beam-pair with limited overhead. The CBS procedure can further benefit from the knowledge of some additional structure in the channel. As mmWave systems are envisioned to be deployed in conjunction with sub-6 GHz systems, we use the spatial information...
Emulation of a realistic environment is modeled in an anechoic chamber to measure the performance of a Base Station Massive MIMO Array antenna using a Spatial Channel Model. The first bounce path establishes the angles of departure and angle spreads observed by the MM array and each is produced by probes placed in the chamber. A channel emulator is utilized to model the full connection between the...
MIMO technology allows high-data rates in wireless devices. A 4 × 4 MIMO multiband antenna system is proposed using small non-resonant elements placed each one at different corners of a smartphone platform. Electromagnetic analysis as well as an experimental demonstrator show that a compact solution using four non-resonant elements of 10 mm × 3.2 mm × 3.2 mm operating at 824MHz-960MHz and 1710MHz-2400MHz...
More and more radio systems are incorporated in modern automobiles e.g. multiple mobile communication standards for car-to-car or car-to-infrastructure communications like LTE, ITS G5, satellite navigation, radar detection, and so on. Due to the intimate relation between wireless information and the automotive state of operation, these complex systems need to be tested extensively and under realistic...
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