Wave Wireless Communication Research Articles

Analysis of Radio Frequency Blackout for a Blunt-Body Capsule in Atmospheric Reentry Missions

A numerical analysis of electromagnetic waves around the atmospheric reentry demonstrator (ARD) of the European Space Agency (ESA) in an atmospheric reentry mission was conducted. During the ARD mission, which involves a 70% scaled-down configuration capsule of the Apollo command module, radio frequency blackout and strong plasma attenuation of radio waves in communications with data relay satellites and air planes were observed. The electromagnetic interference was caused by highly dense plasma derived from a strong shock wave generated in front of the capsule because of orbital speed during reentry. In this study, the physical properties of the plasma flow in the shock layer and wake region of the ESA ARD were obtained using a computational fluid dynamics technique. Then, electromagnetic waves were expressed using a frequency-dependent finite-difference time-domain method using the plasma properties. The analysis model was validated based on experimental flight data. A comparison of the measured and predicted results showed good agreement. The distribution of charged particles around the ESA ARD and the complicated behavior of electromagnetic waves, with attenuation and reflection, are clarified in detail. It is suggested that the analysis model could be an effective tool for investigating radio frequency blackout and plasma attenuation in radio wave communication.

Hybrid MIMO Architectures for Millimeter Wave Communications: Phase Shifters or Switches?

Hybrid analog/digital MIMO architectures were recently proposed as an alternative for fully-digitalprecoding in millimeter wave (mmWave) wireless communication systems. This is motivated by the possible reduction in the number of RF chains and analog-to-digital converters. In these architectures, the analog processing network is usually based on variable phase shifters. In this paper, we propose hybrid architectures based on switching networks to reduce the complexity and the power consumption of the structures based on phase shifters. We define a power consumption model and use it to evaluate the energy efficiency of both structures. To estimate the complete MIMO channel, we propose an open loop compressive channel estimation technique which is independent of the hardware used in the analog processing stage. We analyze the performance of the new estimation algorithm for hybrid architectures based on phase shifters and switches. Using the estimated, we develop two algorithms for the design of the hybrid combiner based on switches and analyze the achieved spectral efficiency. Finally, we study the trade-offs between power consumption, hardware complexity, and spectral efficiency for hybrid architectures based on phase shifting networks and switching networks. Numerical results show that architectures based on switches obtain equal or better channel estimation performance to that obtained using phase shifters, while reducing hardware complexity and power consumption. For equal power consumption, all the hybrid architectures provide similar spectral efficiencies.

Millimeter Wave Wireless Communications (Rappaport, T., et al; 2014) [Book review

This book presents broad information in the area of millimeter wave wireless communications, specifically dealing with communications, circuits, antennas, propagation, and networking and standards. With the proliferation of cellular wireless devices, such as smartphones and the rapid adoption of Internet of Things (IoT) technology, the demand for higher wireless bandwidth will only increase. This demand will be further exacerbated by the fact that smartphones are quickly becoming the devices of choice for people to watch multimedia content. The 4G technologies are fast going to reach their limits to satisfy this demand. This has resulted in the search for technologies to help increase the available bandwidth. Millimeter wave (mmWave) technology, wherein communication happens in the spectrum range of 3–30 GHz, appears to be one of the promising technologies.

Planar High Gain Dielectric Loaded Exponentially Tapered Slot Antenna for Millimeter Wave Wireless Communications

A new and upcoming application is the use of millimeter wave (MmW) antennas for high date rate point-to-point connections to serve gigabit (Gi-Fi) wireless communications. The concept of substrate integrated waveguide (SIW) and exponentially tapered slot (ETS) antenna are used together design a high gain, efficient planar dielectric loaded antenna for MmW Gi-Fi wireless communications at 60 GHz. The SIW is used to feed the antenna and a dielectric loading is utilized in front of the antenna to increase the gain. The dielectric loaded ETS antenna and compact SIW feed are fabricated on a single substrate, resulting in low cost and easy fabrication. The antenna with elliptical shaped dielectric loaded is fabricated using printed circuit board process. The measured gain of the antenna is 11.4 dB, while the radiation efficiency of 96.84 % is obtained at 60 GHz. The measurement results are compared with simulated results.

Book reviews [Two books reviewed

Reviews the following books: Mobility Protocols and Handover Optimization: Design, Evaluation and Application (Dutta, A. and Schulzrinne, H.; 2014); Millimeter Wave Wireless Communications (Rappaport, T.S., Heath Jr, R.W., Daniels, R.C. and Murdock, J.N.; 2015)

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

Indoor radio link characterization studies for millimeter wave wireless communications utilizing dielectric-loaded exponentially tapered slot antenna

A trend that is pragmatic in today’s wireless communications is the demand for the supportof increasing data rates over short distances. Through the last decade, ample knowledge about the 60 GHz millimeter wave (MmW) channel has been gathered and different architectures have been analyzed to develop MmW communication systems for commercial applications. The usage of MmW frequencies is perceived as a resilient entrant for realizing future, gigabit wireless communications as it offer vast bandwidths for short-range indoor communications. In this work, the MmW antenna solutions for exponentially tapered slot (ETS) antenna using substrate integrated waveguide (SIW) technology and indoor radio wave propagations are studied at 60 GHz for wireless communications. The SIW is used to feed the antenna, and a dielectric loading is utilized in front of the antenna to increase the gain. The antenna with elliptical-shaped dielectric loaded is fabricated using printed circuit board process. The measurement results are compared with simulated results. Then, the indoor short-range radio wave propagation study is carried out using ETS antenna with RF measurement equipment to measure and model propagation channels at 60 GHz. The attained simulations are compared to the experimental results.

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

A Review of Ionospheric Scintillation Models

This is a general review of the existing climatological models of ionospheric radio scintillation for high and equatorial latitudes. Trans-ionospheric communication of radio waves from transmitter to user is affected by the ionosphere which is highly variable and dynamic in both time and space. Scintillation is the term given to irregular amplitude and phase fluctuations of the received signals and related to the electron density irregularities in the ionosphere. Key sources of ionospheric irregularities are plasma instabilities; every irregularities model is based on the theory of radio wave propagation in random media. It is important to understand scintillation phenomena and the approach of different theories. Therefore, we have briefly discussed the theories that are used to interpret ionospheric scintillation data. The global morphology of ionospheric scintillation is also discussed briefly. The most important (in our opinion) analytical and physical models of scintillation are reviewed here.

Three-dimensional indoor localisation system using radio frequency identification tags

Radio Frequency Identification (RFID) is an information exchange technology based on radio wave communication. It is also a possible solution to indoor localisation. Owing to multipath propagation and anisotropic interference in the indoor environment, theoretical propagation models are generally not sufficient for RFID-based localisation. In fact, the received radio frequency signal distribution may not even be monotonic and this makes range-based localisation algorithms less accurate. On the other hand, range-free localisation algorithms, such as k Nearest-Neighbour (kNN), require reference tags to be spread throughout the whole three-dimensional (3D) space which is frequently not practical. In this work, a hybrid real-time localisation algorithm that combines reference tags with Received Signal Strength Indicator (RSSI) ranging is introduced to improve RFID-based 3D localisation in indoor environments. The localisation algorithm is implemented in MATLAB and is synchronised with radio signal data in real-time. Results show that the proposed hybrid algorithm achieves an average 3D localisation error of 1.08 m which represents a significant improvement over algorithms that use only kNN or RSSI.

Absorption of Microwaves in Low Intensity Eucalyptus Litter Fire

A fuel bed was constructed where various vegetation species could be used as combustion fuel. The fuel bed was equipped with a thermocouple to measure fire temperature and a two-port automatic network analyser to measure microwave scattering parameters in flame medium. The parameters are then used to determine microwave propagation characteristics in fire. The measurements have implications on radio wave communication during wildfire suppression and in remote sensing. The attenuation data also provide an estimation of vegetation fire ionisation and conductivity. Eucalyptus litter fire with a maximum flame temperature of 976 K was set on the fuel bed and X-band microwaves (7.00 - 9.50 GHz) were caused to propagate through the flame. Attenuation of 0.35 - 0.90 dB was measured for microwaves in the frequency range. For the low intensity fire, conductivity was measured to range from 0.00021 - 0.00055 mho/m and electron density was to be the range of 1.83 - 2.24 × 1015 m-3.

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

Special Issue on Signal Processing for Millimeter Wave Wireless Communications

Multi-gigabit millimeter wave wireless communications for 5G: from fixed access to cellular networks

With the formidable growth of various booming wireless communication services that require ever increasing data throughputs, the conventional microwave band below 10 GHz, which is currently used by almost all mobile communication systems, is going to reach its saturation point within just a few years. Therefore, the attention of radio system designers has been pushed toward ever higher segments of the frequency spectrum in a quest for increased capacity. In this article we investigate the feasibility, advantages, and challenges of future wireless communications over the E-band frequencies. We start with a brief review of the history of the E-band spectrum and its light licensing policy as well as benefits/challenges. Then we introduce the propagation characteristics of E-band signals, based on which some potential fixed and mobile applications at the E-band are investigated. In particular, we analyze the achievability of a nontrivial multiplexing gain in fixed point-to-point E-band links, and propose an E-band mobile broadband (EMB) system as a candidate for the next generation mobile communication networks. The channelization and frame structure of the EMB system are discussed in detail.

Prediction Performance of Blackout and Plasma Attenuation in Atmospheric Reentry Demonstrator Mission

A numerical simulation model that combines the plasma flows and electromagnetic waves around a reentry vehicle during atmospheric reentry was developed to evaluate the radio frequency blackout and plasma attenuation. The physical properties of the plasma flow in the shock layer and wake region were obtained using a computational fluid dynamics technique. The electromagnetic waves were expressed using a frequency-dependent finite difference time domain method with the plasma properties. Combined simulations were performed for the atmospheric reentry demonstrator of the ESA at various altitudes based on reentry orbit data. The electromagnetic wave behaviors around the vehicle during atmospheric reentry were investigated in detail. Moreover, a parametric analysis with different ionization reaction models was performed. It was confirmed that the vehicle is surrounded by the plasma and the propagation of the electromagnetic waves is prevented at high altitude. Then, the plasma is dissipated and the propagation recovers at low altitude. Validation of the simulation model was performed based on the plasma attenuation history of the experimental flight data. A comparison of the measured and predicted results showed good agreement. It was concluded that the combined simulation model could be an effective tool for investigating the radio frequency blackout and the plasma attenuation of radio wave communication.

A Novel Approach to Study Regional Ionospheric Variations Using a Real-Time TEC Model

Since IGY (International Geophysical Year), through coordinated global observations, ionospheric research has been carried out by many countries. This effort primarily helped in the design and operation of HF radio wave communication systems. The Indian region covers a highly variable part of the equatorial electrojet and EIA (Equatorial Ionisation Anomaly) phenomena making its predictability difficult. With the advent of satellite communication and navigation, the need for accurate ionospheric TEC (Total Electron Content) models at global and regional scales has been stressed. The GAGAN (GPS Aided Geo Augmented Navigation) project jointly undertaken by the Indian Space Research Organisation (ISRO) and the Airport Authority of India (AAI) aims at effectively utilising the Global Navigational Satellite System (GNSS) to determine position coordinates accurately for aircraft precision landing applications. For this purpose the range errors are estimated by using a ground network of TEC stations spread over Indian region. The near simultaneous data collected from these dual frequency GPS stations can be used to generate the geo-referenced TEC values for various applications. The author has developed necessary algorithm and associated computer programmes for a real-time vertical TEC (VTEC) model based on TEC data collected from the GAGAN ground based network stations. The model has been tested and sample results presented here show that it adequately provides for the latitudinal resolution of 1° for the entire longitude span and also for two longitude blocks (73 - 83 & 83 - 93°E) separately. Cubic spline and bilinear interpolation techniques are used for filling up temporal and spatial data gaps. The model provides tabulated output of hourly average VTEC data with latitude for ready use, as well as graphical displays of VTEC maps and contours for monitoring purpose. The real-time model and its extensions are also being used for detailed scientific studies; examples of these show small day to day variability of VTEC without any change in solar activity and indication of the change in the shape of the VTEC diurnal curve with season. The present model will be used for further studies to derive the monthly average variation of the diurnal pattern and the relationship between VTEC peak amplitudes with changes in solar activity. The new information generated can be fed back to improve the real-time model so that eventually the dependence of such models on ground based network stations data can be minimised.

An ultrawide tunable range single passband microwave photonic filter based on stimulated Brillouin scattering

A single passband microwave photonic filter with ultrawide tunable range based on stimulated Brillouin scattering is theoretically analyzed. Combining the gain and loss spectrums, tuning range with 44GHz is obtained without crosstalk by introducing two pumps. Adding more pumps, Tuning range multiplying with the multiplication factor equaling to the total quantity of pump can be achieved, which has potential application in microwave and millimeter wave wireless communication systems.

RFID Applications: Prospects and Challenges in Bangladesh

Radio frequency identification (RFID) is an emerging technology, radio wave communication between a microchip and an electronic reader, consisting of data gathering, distribution, and management systems that has the ability to identify or scan information for remoting recognition of objects with increased speed and accuracy. An attempt has been made to know how using of RFID technology helps to improve services and business process efficiency in public and private sectors of Bangladesh. With this aim, we have conducted extensive literature survey. At the end of this attempt, we have come to the conclusion that the potential use of this technology includes RFID chipped passports, human implants, item-level tagging, inventory tracking and access control systems. RFID technology is at its early stage of adoption in Bangladesh with a few business applications and pilot studies. However, when tags begin to be associated with individuals, privacy is threatened. RFID is a new type of threat to personal information and must be treated as such; indeed, it must be recognized that existing privacy legislation is not adequate. This paper also explores some current and emerging applications of RFID in Bangladesh and examines the challenges including privacy and ethical issues arising from its use, as well as addressing potential means of handling those issues.

DIELECTRIC LOADED EXPONENTIALLY TAPERED SLOT ANTENNA UTILIZING SUBSTRATE INTEGRATED WAVEGUIDE TECHNOLOGY FOR MILLIMETER WAVE APPLICATIONS

A novel compact dielectric loaded Exponentially Tapered Slot (ETS) antenna using Substrate Integrated Waveguide (SIW) technology is presented in this paper for Millimeter (Mm) wave wireless communication applications. The dielectric loaded ETS antenna and compact SIW feed are fabricated on a single substrate. The compact SIW feeding structure results in a considerable reduction in size and eliminates the unwanted radiations from feed. The proposed antenna is designed, fabricated, and investigated at 60GHz. Furthermore, the proposed antenna design is simulated using electromagnetic software CST Microwave Studio and the comparison is made with Ansys HFSS to validate the design procedure. The measurement results are compared with simulated results.