Hardware Simulator Design for MIMO Propagation Channel on Shipboard at 2.2 GHz

A wireless communication system can be tested either in actual conditions or with a hardware simulator reproducing actual conditions. With a hardware simulator it is possible to freely simulate a desired radio channel, making it possible to test “on table” mobile radio equipments. This paper presents new architectures for the digital block of a hardware simulator of MIMO propagation channels. This simulator can be used for LTE and WLAN IEEE 802.11ac applications, in indoor and outdoor environments. However, in this paper, specific architectures of the digital block of the simulator for shipboard environment are presented. A hardware simulator must reproduce the behavior of the radio propagation channel. Thus, a measurements campaign has been conducted to obtain the impulse responses of the shipboard channel using a channel sounder designed and realized at IETR. After the presentation of the channel sounder, the channel impulse responses are described and implemented. Then, the new architectures of the digital block of the hardware simulator, implemented on a Xilinx Virtex-IV FPGA are presented. The accuracy, the occupation on the FPGA and the latency of the architectures are analyzed.     

An Extended-AMATA Indoor Propagation Model for GSM 900/1800 MHz and Wi-Fi 2.4 GHz Frequencies

In a previous article, we reported on a novel indoor propagation model; we called the AMATA model, which we applied at 900 MHz and 2.4 GHz frequencies. The model could be applied at both GSM and wireless LAN frequencies. The developed formula merits, on its own, as a novel fourth power effective attenuation equation, which relies on the number of wall separations within the floor. This paper reports an extended-AMATA indoor propagation model that generally describes university and office type buildings. A sample of four different multi-floor building structures that have a stone block type outer wall was chosen. Those flat roofed, stone built, multi floor buildings are very common, not only in Palestine, but probably in vast areas in the Middle East region. The new model benefits over the previous one, applied at 900 MHz, in that it can be extended to cellular base-stations, transmitting at 1800 MHz frequency and outdoor Wi-Fi basestations, as opposed to indoor access points, transmitting at 2.4 GHz. The work is of paramount importance to cellular and Wi-Fi network operators, transmitting at 900/1800 MHz and 2.4 GHz frequency bands. Our new model can be applied with a high confidence level to buildings, similar to the sample of buildings, we measured.     

Wideband Millimeter-Wave Channel Characterization in an Open Office at 26 GHz

Based on the newest frequency allocation for the fifth generation (5G) radio systems at 26 GHz millimeter wave band by the World Radio Communications Conference, this paper investigates the wideband channel properties by measurements carried out in the LOS and NLOS environments at 26 GHz with 1 GHz bandwidth in an open office at KeySight Beijing, China, which is a representative of an indoor hotspot scenario. In the time domain measurements, an omni-directional biconical horn is used at the transmitter, while at the receiver a 24.3 dBi horn is applied and rotated with 5° angular step in the whole azimuth plane, and from ?20° to 30° in the elevation plane with 10° angular step. In the work, two kinds of path-loss models are developed, namely directional and omni-directional models by using close-in and float intercept methods. The directional path-loss model is useful for adopting beamforming techniques. The large scale channel parameters such as the shadow fading, root mean square (RMS) delay spread, RMS angular spread in the azimuth and elevation planes, Ricean K-factor, number of clusters and their correlations are investigated for the fifth generation (5G) link and system level simulations. A new method for extracting number of clusters is proposed to find the peak power within a sliding window. The power angular profiles are employed at the measurement locations for propagation mechanisms studies. We believe that the newest results in this work are useful in the simulations and planning for future 5G radio systems at 26 GHz.     

Indoor Radio Propagation and Interference in 2.4 GHz Wireless Sensor Networks: Measurements and Analysis

In wireless sensor networks (WSNs), the performance and lifetime are significantly affected by the indoor propagation and the interference from other technologies using the 2.4 GHz band. Next to an overview of the propagation and coexistence issues in the literature, we present a model for analysing these effects in WSNs. We also present our measurements results on the indoor propagation, the interference of the microwave oven (MWO) and their impact on the performance of the WSN. The propagation measurements reveal significant influence of the multipath: changing a node position with a few centimetres or changing the communication channel can lead up to 30 dB difference in the received power. The power leakage of MWO has been observed around $-$ 20 dBm at 1 m distances to the oven. This leads to extra retries of the 802.15.4 messages which matches our simulation results: the packet success ratio at first try decreases to 30–40 %, which increases the average active time of the sensor, closely located to the MWO. We observe that the ON–OFF pattern of the MWO could be exploited by WSNs to improve the performance.     

Terahertz MMICs and Antenna-in-Package Technology at 300 GHz for KIOSK Download System

Toward the realization of ultra-fast wireless communications systems, the inherent broad bandwidth of the terahertz (THz) band is attracting attention, especially for short-range instant download applications. In this paper, we present our recent progress on InP-based THz MMICs and packaging techniques based on low-temperature co-fibered ceramic (LTCC) technology. The transmitter MMICs are based on 80-nm InP-based high electron mobility transistors (HEMTs). Using the transmitter packaged in an E-plane split-block waveguide and compact lens receiver packaged in LTCC multilayered substrates, we tested wireless data transmission up to 27 Gbps with the simple amplitude key shifting (ASK) modulation scheme. We also present several THz antenna-in-packaging solutions based on substrate integrated waveguide (SIW) technology. A vertical hollow (VH) SIW was applied to a compact medium-gain SIW antenna and low-loss interconnection integrated in LTCC multi-layer substrates. The size of the LTCC antennas with 15-dBi gain is less than 0.1 cm³. For feeding the antenna, we investigated an LTCC-integrated transition and polyimide transition to LTCC VH SIWs. These transitions exhibit around 1-dB estimated loss at 300 GHz and more than 35 GHz bandwidth with 10-dB return loss. The proposed package solutions make antennas and interconnections easy to integrate in a compact LTCC package with an MMIC chip for practical applications.     

An Indoor Propagation Model Based on a Novel Multi Wall Attenuation Loss Formula at Frequencies 900 MHz and 2.4 GHz

This paper describes an indoor propagation model pertaining to a sample of six different multi-floor building structures that have a stone block type outer wall and are generally described as university, hospital and office type buildings. Those flat roofed, stone built, multi floor buildings are very common, not only in Palestine, but probably in vast areas in the Middle East region. The goal is to come up with a relatively general model that would be both reliable and representative to a wider sample of multi-floor buildings, falling under a similar building structure classification. The improved model; we name the AMATA model, lends itself to its generalization for the GSM and wireless LAN frequencies as well as the developed multiwall effective attenuation fourth power nonlinear equation that solely relies on the number of wall separations within the floor. A clear improvement in the standard deviation of the mean path loss resulted in comparison to the well known indoor ITU path loss model. Our model can be applied with a high confidence level to the wider range of buildings similar to the classification type of the building structure sample, we conducted measurements upon.     

Propagation Path Loss and Materials Insertion Loss in Indoor Environment at WiMAX Band of 3.3 to 3.6?GHz

The purpose of this study is to characterize the indoor channel for IEEE 802.16 (WiMAX) at 3.3?C3.6?GHz frequency. This work presents a channel model based on measurements conducted in commonly found scenarios in buildings. These scenarios include closed corridor, wide corridor and semi open corridor. Path loss equations are determined using log-distance path loss model and a Rayleigh multipath induced fading, Normal multipath induced fading or a combination of both. A numerical analysis of measurements in each scenario was conducted and the study determined equations that describe path loss for each scenario. Propagation loss is given for 300?MHz bandwidth. This work also represents the insertion loss of different materials and the obstruction loss due the existence of human beings between the transmitting antenna and the receiving one.     

Coupling and Propagation of Sommerfeld Waves at 100?and 300?GHz

The coupling between a linearly-polarized gaussian beam and a Sommerfeld wave propagating on a circular metallic wire is obtained owing to a differential phase element inserted in front of the metal wire. At millimeter-wavelengths we calculate a theoretical maximum coupling efficiency of 32% for this system in spite of the metal nature and radius in the range of a few hundreds of microns. A detailed experimental study of 100 and 300 GHz Sommerfeld waves propagating on stainless steel and tungsten wires is reported. The measured field at any distance from the wire compares well with theoretical predictions.     

Comparisons of system architectures for microwave-photonics transmissions at 60 GHz

We report here on different system architectures for a wireless link operating in the 60 GHz range, which has a high potential for use in short range and highly secure high data rate applications. The millimetre wave around 60 GHz is generated by photonic heterodyning or microwave-photonics using radio-over-fibre concept of transmission. Low error transmission using two techniques at data rates up to 4.2 Gb/s is experimentally demonstrated.     

Optimization of the UTC-PD Epitaxy for Photomixing at 340 GHz

We present a method to optimize the epitaxial layer structure of an InGaAs/InP uni-traveling-carrier photo-diode (UTC-PD) for continuous THz-wave generation. The design approach used is general in that it can be applied for any target frequency while this study focuses on 340 GHz. The photodiode epitaxy is modeled and optimized using a TCAD software implementing the hydrodynamic semiconductor equations. This physical device model was found to be in good agreement with reported experimental results. It is shown that the UTC-PD can generate ~1 mW at 340 GHz by choosing the optimum absorption layer and collection layer thicknesses.     

Complex permittivity of soil and water mixtures at 9 GHz

Measurements of the complex permittivity of many soil samples were conducted using the evanescent waveguide technique at 9 GHz. The complex permittivity was taken as a function of moisture content. The experimental results were interpreted using Wiener's theory for dielectric mixtures to evaluate the degree of binding of water in soils.     

Impact of antenna radiation pattern variation on the performance of SPMA at 28 GHz

The target of this paper is to analyze the impact of variation in antenna radiation pattern on the performance of Single Path Multiple Access (SPMA) in urban/dense-urban environment. For this study, an extended 3GPP antenna model, and 3D building data from an urban area of Helsinki city is used. The simulations are performed at 28 GHz frequency using “sAGA” a MATLAB based 3D ray tracing tool. The variables considered for the series of simulations are Front to Back Ratio (FBR), Side Lobe Level (SLL), and Half Power Beamwidth (HPBW) of an antenna in horizontal and vertical plane. Network performance is compared in terms of metrics like signal strength, SINR, and capacity. This paper also presents the spectral efficiency and power efficiency analysis. The performance of SPMA was found susceptible to the change in antenna radiation pattern, and the simulation results show a significant impact of radiation pattern on the capacity gain offered by SPMA. Interestingly, SPMA was found a fairly power efficient solution with respect to the traditional macro cellular network approach. However, the level of power efficiency heavily depends upon the antenna beamwidth and on other beam parameters.     

Improving a Hybrid Method of Indoor Propagation Modeling for Wireless Communications Systems

1　IntroductionThewirelesscommunicationsystemshavebeendevelopedrapidlyintherecentyears.Ithasnotonlycalledresearchers’attentiontomodelingtechniquesinInternet[1 ] ,butalsomoreandmorepeopleen gagedin propagationmodelingforindoorwirelesscommunications.Theeffectivedesign ,assessmentandinstallationofaradionetworkinanindoorenvi ronmentrequireanaccuratecharacterizationoftheradiopropagationchannel.Raytracingisapopularmethodforthepredictionofradiochannelcharacter isticsofwirelesscommunicationsystems.R…     

Review of Wireless Personal Communications Radio Propagation Models in High Altitude Mountainous Areas at 2.6 GHz

This paper presents five commonly used radio propagation models (RPMs) which are suitable for the prediction of path loss in macrocell environments of LTE wireless communication systems. These RPMs’ application in high altitude mountainous areas networks (HAMANETs) environment requires further validation and studies. Through using the measured path loss in the HAMANETs at 2.6 GHz to calculate the predicted value of the five RPMs and the measured value’s mean error (ME), root mean square error, and error standard deviation (ESTD), we verified the predicted value of the SPM model that is closer to the actual measurement. On this basis, the empirical propagation model in HAMANETs environment is corrected. When correcting, a method to calculate base station’s effective antenna height and propagation distance is provided by using the altitude above sea level data. This method can reduce the error that the mountainous areas are simplified to the flat-terrain in the existed propagation models. A linear least square method is used to calculate the optimal propagation model. Finally, the ME is the smallest, and the ESTD is less than 8 dB, which indicate that the corrected propagation model is more suitable for the actual environmental path loss’s prediction. The results show that the path loss factor of the test area is about 65 dB, including the influence of the high altitude, mountains, vegetation, and air humidity in HAMANETs environment. The study results can provide useful advice to the evaluation and verification of personal wireless communications in the HAMANETs. Furthermore, using the correction method proposed in this paper can correct propagation models suitable for the different propagation environments to improve the accuracy and efficiency of wireless network optimization.     

Performance Analysis of Tags Collection Time on A New Architecture of 2.4 GHz Embedded Active RFID System for Indoor and Outdoor Tracking and Monitoring Applications Based on IEEE 802.15.4 Standard

This paper focuses on the analysis of tags collection time of 2.4 GHz embedded active Radio Frequency Identification (RFID) system for indoor and outdoor real-time tracking and monitoring applications based on IEEE 802.15.4 standard. The main novelty of the system is the implementation of the communication method in order to provide Machine to Machine (M2M) communication and automated switching mechanism between indoor and outdoor location by utilizing active RFID, Wireless Sensor Network (WSN), Global Positioning System (GPS) and mobile communication on a single platform. In this work, GPS receiver covers outdoor location tracking, while active RFID provides identification and Receive Signal Strength Indicator (RSSI) reading for each tag holder to cover indoor location tracking especially near or inside building where location information is not detected by GPS. Several experiments were conducted on three different RFID tags which were active RFID tag embedded with GPS and GSM (ERFIDG2), active RFID tag embedded with GPS (ERFIDG) and standalone RFID tag communicating with the same active RFID reader. The experiment was done to evaluate the communication performance of the active RFID in terms of tags collection time using Transparent (AT) and Application Programming Interface (API) mode. The experiment was extended to measure tags collection time in single hop and multi hops communication for Tag Talk First (TTF) and Reader Talk First (RTF) protocols. The results show that the proposed active RFID system (ERFIDG2) is better than the standalone and ERFIDG systems. The in-depth research done in this work is to study the experience and identify the challenges that will be faced in the development and implementation of a wireless RFID-based system for tracking and monitoring applications.     

Development of 28?GHz and 77?GHz, Mega-Watt Gyrotrons for Fusion Devices

A 28 GHz 1 MW with TE_8,3 cavity for GAMMA10 tandem mirror and a 77 GHz 1.5 MW gyrotron with TE_18,6 for Large Helical Device (LHD) have been developed to upgrade their Electron Cyclotron Heating (ECH) systems. In the 28 GHz gyrotron, the maximum power of 1.05 MW was obtained, which is in agreement with its design target value. And the high efficiency of 40% without collector potential depression (CPD) was obtained with 0.8 MW. In the first and second 77 GHz gyrotrons, 0.8 MW 3.6 sec., 0.3 MW 60 sec operations have been achieved, but several issues due to the stray RF and velocity dispersion have been found, too. In consideration of these, the design improvement was performed to aim at 1.5 MW in the third tube. In the short pulse test, the maximum output power of 1.6 MW and the maximum total efficiency of 49.4% with CPD were obtained. In the long pulse test, the pulse length extended to 5 sec with 1 MW, 1800 sec with 0.1 MW, 1.6 sec with 1.5 MW. Total injection power of 3.1 MW to LHD plasma has been achieved. It is shown that the electron beam pitch factor ?? decreases with increasing of beam current, comparing with the experimental and calculation results.     

RF Behavior of Cylindrical Cavity Based 240 GHz, 1 MW Gyrotron for Future Tokamak System

In this paper, we present the RF behavior of conventional cylindrical interaction cavity for 240 GHz, 1 MW gyrotron for futuristic plasma fusion reactors. Very high-order TE mode is searched for this gyrotron to minimize the Ohmic wall loading at the interaction cavity. The mode selection process is carried out rigorously to analyze the mode competition and design feasibility. The cold cavity analysis and beam-wave interaction computation are carried out to finalize the cavity design. The detail parametric analyses for interaction cavity are performed in terms of mode stability, interaction efficiency and frequency. In addition, the design of triode type magnetron injection gun is also discussed. The electron beam parameters such as velocity ratio and velocity spread are optimized as per the requirement at interaction cavity. The design studies presented here confirm the realization of CW, 1 MW power at 240 GHz frequency at TE_46,17 mode.