PHY3- Millimeter-wave communications and antenna arrays
Wednesday, 20 June 2018, 11:00-12:30, E1 hall
Session chair: Didier Bourse (Nokia, France)
11:00 – Total Array Gains of Polarized Millimeter-Wave Mobile Phone Antennas
Katsuyuki Haneda and Mikko Heino (Aalto University, Finland); Jan Järveläinen (Premix & AALTO University, Finland)
This paper studies a gain of an antenna array implemented on a mobile device operating at a millimeter-wave radio frequency. Assuming that mobile phones at a millimeter-wave range operate with a single transceiver chain and analog beamforming like phased arrays, its total array gain is attributed to average gains of antenna elements and signal precoding or combining gains in excess to received power from a single-element dual-polarized omni-directional antenna. The total array gain circumvents the ambiguity of conventional array gain which cannot be uniquely defined as there are multiple choices of a reference single-element antenna in an array. Different polarized 8-element patch antenna arrays implemented on a mobile phone chassis, i.e., uniform linear array (ULA) and distributed array (DA) operating at 60 GHz, are studied. The antenna elements are placed so that they cover vertical, slanted or horizontal polarizations. The gain is evaluated for different orientations of the chassis along with effects of a body torso and a finger of a person operating the phone The gain in a small-cell scenario in an airport shows that DA achieves higher gains than ULA regardless of polarization states of antenna elements at the base and mobile stations, and of the existence of line-of-sight in radio channels. Antenna polarizations do not make much impact on the total array gain as random orientation of a mobile phone and finger shadowing modifies the polarization states. The results show that antenna array geometry is the more influential design aspect than polarization when a single transceiver chain is considered.
11:18 – Out-of-Band Interference in 5G mmW Multi-Antenna Transceivers: Co-existence Scenarios
Marko E Leinonen and Nuutti Tervo (University of Oulu, Finland); Olli Kursu (Centre for Wireless Communications, University of Oulu, Finland); Aarno Pärssinen (University of Oulu, Finland)
Large antenna arrays used for compensating the mmW path loss gives interesting perspectives for considering out-of-band emissions and reception signals to be direction dependent. In addition, co-existence of lower frequency and mmW systems set special requirements for both conventional cellular and mmW systems. This paper discusses on these two cases as the most important out-of-band interference scenarios in fifth generation systems. Effects of intermodulation and adjacent channel leakage are discussed in both mmW beamforming transceiver and receiver, respectively. It is concluded that distortion is behaving differently in multi-antenna transmitter than at the receiver. Measured and simulated examples of the nonlinear behavior of an array are given for receiver and transmitter, respectively. Furthermore, smart array linearization scheme given as a reference provides new perspective to consider the direction dependent out-of-band distortion as a part of the future cellular standards.
11:36 – Effects of Unit Cell Enlargement and 1-Bit Quantization in 5G Linear Metasurface Antennas
Xavier Artiga (Centre tecnològic de Telecomunicacions de Catalunya (CTTC), Spain)
Metasurface antennas constitute an attractive low cost, low complexity and low power alternative to phased arrays for 5G millimeter wave communications. This paper addresses the design of low complexity linear metasurface antennas with scanning capabilities, based on modulated surface impedances. In particular, it shows that with a proper design, the number of reconfigurable unit cells can be reduced up to a 50% without a significant reduction of the radiation properties of the antenna, by means of enlarging the unit cell sizes. Besides, the paper proposes a 1-bit reconfigurable unit cell and demonstrates the feasibility of 1-bit metasurface antennas, enabling the use of MEMS switches for loss reduction, scanning stability improvement and for simplifying the interface with digital circuitry. Finally, cell enlargement and 1-bit quantization are jointly assessed, revealing that their effects are cumulative and that in the case of 1-bit solutions, the unit cell dimensions must be carefully selected.
11:54 – Approaching Two Dimensional Mazo Limit: A Novel Non-orthogonal Waveform with Inter-carrier Zero Correlation Window
Fan Yang (Fujitsu R&D Center Co., Ltd, P.R. China)
A novel multicarrier waveform, which can double the spectral efficiency of the orthogonal frequency multiplexing (OFDM) signal, is proposed in this study. It is based on a preprocessing proposed in this work over the semi-orthogonal frequency division multiplexing (SOFDM) signal, whose subcarrier spacing is half of that of OFDM. This preprocessing is designed to minimize the inter-carrier interference (ICI) in the original SOFDM signal. To this end, it is performed by multiplying the sine portion of each subcarrier with a special bipolar clock signal governed by an integer-valued parameter M and thus makes each subcarrier orthogonal to all its adjacent (M-1) subcarriers. This desired property is called inter-carrier zero correlation window (ZCW) and is proved in this paper by mathematical induction. According to the ZCW property, when M is not less than the number of subcarriers, the ICI among the subcarriers becomes zero. Thus, the performance and receiver complexity can be optimized simultaneously. However, it is also found that the side lobe level of this signal increases with the rise of $M$, which could lead to a high out-of-band (OOB) power emission. To remove this unwanted effect, a smoothing function is proposed further to be used over the bipolar clock signal. The simulation results prove that it can double the spectral efficiency of the OFDM signal without performance loss or side lobe distortion. Thus, it approaches the two-dimensional Mazo limit in the faster-than-Nyquist (FTN) theory.
12:12 – Transmisson Hub and Terminals for Point to Multipoint W-band TWEETHER System
Claudio Paoloni (Lancaster University, United Kingdom (Great Britain)); François Magne (WHEN-AB & SARL, France); Frederic Andre (Thales Electron Devices, France); Joel Willebois (BOWEN, France); Quang Trung Le (HF Systems Engineering GmbH & Co. KG, Germany); Xavier Begaud (LTCI, Télécom ParisTech, Université Paris-Saclay, France); Giacomo Ulisse (Johann Wolfgang Goethe-Universität, Germany); Viktor Krozer (Goethe University of Frankfurt am Main, Germany); Rosa Letizia (Lancaster University, United Kingdom (Great Britain)); Marc Marilier (OMMIC, France); Antonio Ramirez (Fibernova Systems, Spain); Ralp Zimmerman (HF System Engineering, Germany)
The European Commission Horizon 2020 TWEETHER project will conclude the activity in April 2018 with the release of one transmission hub and three network terminal equipment for enabling the first W-band, 92 – 95 GHz, point to multipoint system, for high capacity backhaul and fixed access. The project ambition has been to develop the European technology for a breakthrough in millimeter wave wireless networks, by introducing the use of traveling wave tubes to achieve the required transmission power for covering, with low-gain antennas, a wide area sector with radius longer than 1 km. The lack of transmission power has so far prevented the use of point to multipoint distribution in millimeter wave bands. At W-band, 3 GHz bandwidth is available to permit up to 10 Gbps/km2 area, capacity to backhaul small cells in a flexible and cost-effective way. The TWEETHER system is also designed to provide high throughput fixed access. This paper will describe the latest results and the technological advancements the project generated, bringing Europe at the state of the art for point to multipoint millimeter wave wireless networks.