In this paper we propose a Downlink Angle of Departure (DL-AOD) positioning algorithm for UE coordinates estimation using channel measurements. The channel estimation is performed with a multi-element transmit antenna array at the base station (gNB) and a single or multi-element receive antenna array at the user device (UE). The algorithm performs total receive channel power maximization with respect to the multi-dimensional space-time filter coefficients to derive an optimal DL-AOD solution. It is shown that the DL-AOD measurements may suffer from the Non-Line of Sight (NLOS) propagation phenomenon, specifically in indoor environments, that causes an angular bias relative to the true Line of Sight (LOS) direction. To reduce the impact of NLOS links on the resulting positioning accuracy the reliability function is introduced for correct weighting of the DL-AOD measurements in the positioning equations. The performance evaluation of the proposed algorithm is provided for the Industrial Internet of Things (I-IoT) use case.

This paper presents a detailed analysis of the impact of power amplifier (PA) non-linearity on the performance of single carrier (SC) and OFDM systems in 60 GHz spectrum. The efficiency of the considered systems was analyzed by estimating values of the power amplifier output backoff needed to meet the requirements on the transmit spectrum mask (TSM) compliance and error vector magnitude (EVM). Different models of the PA including an experimentally measured model for the 60 GHz PA were considered. It was estimated that for many types of modulations and PA models, SC system can have up to 1.5 dB higher output power than OFDM system. However, for the experimental PA model accounting for amplitude modulation-phase modulation distortion in addition to amplitude modulation amplitude modulation distortion, the difference between the OFDM and SC output power levels was minimal, and OFDM even had approximately 1 dB better performance than SC for the BPSK modulation. A potential improvement in the transmit power due to application of digital predistortion techniques was estimated for both systems to be in the range from 1.5 to 3.4 dB.

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.

This paper presents the results of the spatial reuse mode performance analysis for millimeter-wave (mmWave) WPAN systems with steerable high-directional antennas. The practical approach to the spatial reuse problem solution is proposed and two spatial scheduling algorithms for spatial reuse mode implementation are presented. The system level simulations are used to estimate the performance of the proposed algorithms. It is demonstrated that the introduction of the spatial reuse mode for the indoor mmWave WPAN system with 8 parallel communication links will increase the overall mmWave WPAN system throughput in 3-5 times in comparison with conventional time division mode.

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.