Alexander Maltsev

Experimental investigations of 60 GHz WLAN systems in office environment

This paper presents the results of an experimental investigation of 60 GHz wireless local area network (WLAN) systems in an office environment. The measurement setup with highly directional mechanically steerable antennas and 800 MHz bandwidth was developed and experiments were performed for conference room and cubicle environments. Measurement results demonstrate that the 60 GHz propagation channel is quasioptical in nature and received signal power is obtained through line of sight (LOS) and reflected signal paths of the first and second orders. The 60 GHz WLAN system prototype using steerable directional antennas with 18 dB gain was able to achieve about 30 dB baseband SNR for LOS transmission, about 15-20 dB for communications through the first-order reflected path, and 2-6 dB SNR when using second-order reflection for the office environments. The intra cluster statistical parameters of the propagation channel were evaluated and a statistical model for reflected clusters is proposed. Experimental results demonstrating strong polarization impact on the characteristics of the propagation channel are presented. Cross-polarization discrimination (XPD) of the propagation channel was estimated as approximately 20 dB for LOS transmission and 10-20 dB for NLOS reflected paths.

Triangular systolic array with reduced latency for QR-decomposition of complex matrices

The novel CORDIC-based architecture of the triangular systolic array for QRD of large size complex matrices is presented. The proposed architecture relies on QRD using a three angle complex rotation approach that provides significant reduction of latency (systolic operation time) and makes the QRD in such a way that the upper triangular matrix R has only real diagonal elements

Enabling 5G backhaul and access with millimeter-waves

This paper presents the approach of extending cellular networks with millimeter-wave backhaul and access links. Introducing a logical split between control and user plane will permit full coverage while seamlessly achieving very high data rates in the vicinity of mm-wave small cells.

Millimeter-Wave Electronically Steerable Integrated Lens Antennas for WLAN/WPAN Applications

This paper presents design and experimental verification of electronically steerable integrated lens antennas (ILAs) for WLAN/WPAN communication systems operating in the 60-GHz frequency band. The antenna is comprised of a quartz extended hemispherical lens, four switched aperture coupled microstrip antenna (ACMA) elements, and a distribution circuit based on SPDT MMIC switches. The designed ILAs are capable of electronic steering between four different antenna main beam directions in one plane. Fixed beam and electronically steerable ILA prototypes are fabricated and tested. The results are given for two quartz dielectric lenses with the radii of 7.5 and 12.5 mm in order to meet a wide range of WLAN/WPAN requirements. The measured maximum gains of the designed ILAs are 18.4 and 23.2 dBi. The experimental results of the fabricated electronically steerable quartz ILA prototypes prove the simulation results and show

Impact of Polarization Characteristics on 60-GHz Indoor Radio Communication Systems

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Quasi-deterministic approach to mmWave channel modeling in a non-stationary environment

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Experimental Characterization of E-Band Two-Dimensional Electronically Beam-Steerable Integrated Lens Antennas

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Comparative Analysis of Spatial Covariance Matrix Estimation Methods in OFDM Communication Systems

angle sector coverage for the lenses with the 7.5 and 12.5 mm radii, respectively. The bandwidth of the ILAs exceeds the frequency band of 57–66 GHz allocated for WLAN/WPAN applications. The designed ILAs meet all the requirements for steerable directional antennas of 60-GHz WLAN/WPAN systems.

Highly Directional Steerable Antennas: High-Gain Antennas Supporting User Mobility or Beam Switching for Reconfigurable Backhauling

This letter presents experimental results for the polarization impact on 60-GHz indoor radio communication systems. Different transmit and receive antenna polarizations (linear polarizations with different electrical field vector orientations and circular polarizations with different handedness) were used to analyze the degradation in the received signal power due to nonoptimally matched polarization characteristics between the transmit antenna, the propagation channel, and the received antenna. Different signal propagation paths including line-of-sight (LOS) propagation and first- and second-order reflections were investigated. It was found that the degradation due to polarization characteristics mismatch could be as large as 10-20 dB. Polarization characteristics of the transmit and receive antennas providing maximum received signal power were found to be dependent on the type of the signal propagation path. The most robust antenna polarization configuration was identified as a configuration using linear polarization at one end of the communication link and circular polarization at the other end, giving the degradation relative to the optimally matched case of 2-3 dB only.

Mobile WiMAX - Deployment Scenarios Performance Analysis

There is increasing faith that mmWave technology will be part of 5G wireless networks in the wide frequency range 30-90 GHz. Experimental measurements are used to model mmWave channels addressing issues like human body shadowing or reflections due to moving vehicles. In this paper a new quasi-deterministic (Q-D) approach is introduced for modeling mmWave channels. The proposed channel model allows natural description of scenario-specific geometric properties, reflection attenuation and scattering, ray blockage and mobility effects. This new channel modeling approach is of utmost importance for further measurement campaigns planning, channel model characterization, system level simulations and network access capacity estimations.