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This paper presents the performance testing of a train to ground communications network deployed in an underground environment and based on IEEE 802.11ac wireless technology. A fully operational pilot project was deployed in Metro de Madrid facilities for studying the feasibility and performance of the solution. Wireless nodes have been installed in the tunnel and onboard the train. During the testing...
This paper proposes a new feature extraction method for synthetic aperture radar (SAR) images with application to automatic target recognition (ATR). The original SAR image is first represented by a sparse image containing only a few dominant scattering centers (SCs). According to the theory of 2D compressive sensing (CS), a sparse image can be reconstructed from a low dimensional matrix with little...
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...
This contribution discusses a near-field antenna setup capable of delivering multiple input signals with controllable (i.e., user defined) amplitude and phase relations to an antenna under test, operating in the X-band. The setup is based on a Cartesian modulation (phase and quadrature signals) of phase coherent signals, achieved employing broadband passive IQ-mixers controlled via high-resolution...
In this work, a stable marching-on-in-time method is presented to obtain scattering response from arbitrary wire structures illuminated by a Gaussian plane wave directly in the time domain. Contrary to all the available time domain algorithms till now, the present procedure is also capable of handling multiple excitations in a trivial manner. The new procedure is based on the conventional method of...
A reconfigurable over-the-air chamber represents a reverberation chamber whose walls are lined with antennas that are terminated in reconfigurable impedances, allowing synthesis of a wide range of channel conditions for over-the-air testing of mobile wireless devices. While these chambers have potential for practical device testing, finding the right impedances to achieve the desired channel characteristics...
In this contribution the use of circular Plane Wave Generator (PWG) for testing large circular arrays is discussed. In particular, it is shown that the synthesis method proposed in the present paper allows the use of a lower number of radiating elements compared with previous PWG approaches.
This paper describes the challenges of performing accurate antenna measurements at low frequencies (UHF/P-band) and summarizes recent results achieved at ESA-ESTEC on near field testing of several space antennas working at those frequencies. In particular, the paper will present typical uncertainty budgets for medium gain antennas, analyzing the different contributions depending on the test setup...
The wireless industry is getting deeply engaged in the 5th generation communication standard. Despite lack of clear definitions, there are some parameters of the emerging standard which are commonly accepted. Higher frequencies (frequencies above 6 GHz) in the millimeter wave spectrum will be a key component for enabling a massive increase of the available bandwidth and thus data rates for the end...
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...
Large compensated compact ranges are designed for antenna and payload testing of spacecraft antennas and payload units. The Compensated Compact Range concept (CCR) of Airbus does have two major advantages for such measurements. First of all a small cross-polarization (< −40 dB) for frequencies ≥ 3 GHz due to the compensating reflector design. In addition they provide a scanning capability of the...
Massive MIMO is a multi-user technology, where radio base stations (BSs) are equipped with a large number of antennas to simultaneously serve many terminals in the same time-frequency resource. Performance evaluation of such large-scale antenna systems in the design and development stage is challenging. In this paper, we propose to evaluate massive MIMO BSs with a sectorized multi-probe anechoic chamber...
The move of cellular communications from existing frequencies predominantly below 3 GHz up to the lower end of the mmWave bands around 28 GHz and higher, is set to change everything about how we design, test and operate such systems. The successful launch of a new radio (NR) access system is critically dependent on a correct understanding of the quasi-optical propagation behaviour of narrow beamwidth...
Two OTA test methods from literature are selected as those most suited for testing future 5G equipment when assessing end-to-end performance: coherent wave-field synthesis and radiated two-stage or “Wireless Cable”. Both methods have their advantages and disadvantages. Wave-field synthesis is transparent for antenna characteristics of Equipment-under-Test but not viable for large test objects. The...
Base station conformance and performance testing is traditionally carried out in a conducted manner, i.e. test instruments are connected via cables to physical ports on the base station. As the complexity of the base station transceiving circuitry increases and more and more antennas are added to the transceiving links, new measurement techniques based on Over-the-Air metrics are needed. This is especially...
The 4:th generation communication standard is constantly evolving with more features being added to the standard specifications. Carrier aggregation and higher order MIMO are examples of features used to support higher data rates. The addition of features puts new requirements on wireless devices and this increasing complexity implies that Over-the-Air testing is more important than ever. At the same...
An overview of ASKAP phased array feed (PAF) development is presented. New analytical and experimental techniques devised for ASKAP are described. Dedicated engineering test facilities are shown to be invaluable for system verification. Experience gained from PAF manufacture is compared with forecasts, and the importance of routine engineering demonstrated.
In the late 1990's Professor Per-Simon Kildal got the idea that reverberation chambers could be used for characterizing small antennas and mobile devices. Many thought the idea was crazy but he was persistent and worked hard to realize his dream to build a small chamber that could be used by the wireless industry. This paper gives a short history of the research at Chalmers and the creation of the...
The Poggio-Miller-Chan-Harrington-Wu-Tsai (PMCHWT) integral equation is widely used in the scattering analysis of dielectric bodies. The RWG set is normally adopted to expand the electric and magnetic currents in the Method of Moments (MoM) discretization of the PMCHWT formulation. This set preserves normal continuity across edges in the expansion of currents. However, in the analysis of composite...
This paper discusses physical dimensions for a multi probe anechoic chamber based (MPAC) over-the-air (OTA) setup aiming for base station (BS) testing. The target frequency of the simulated massive multiple-input-multiple-output (MIMO) BS arrays is 28 GHz. The assessment is performed with two metrics. The first metric is a new power metric based on assumptions of a code book of fixed beams and planar...
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