Antenna Sites Research Articles

A Novel Application Offloading Algorithm and an Optimized Application Servers Placement for Mobile Cloud Computing

An application's offloading algorithm to over go the limitations of mobile terminals, namely their lack of computing capacity and limited battery autonomy is introduced. The proposed Mobile Application's Offloading algorithm enables to shift applicative jobs from mobile handsets to remote servers. The novelty of MAO consists in considering the Quality of Experience as an additional decision test before proceeding to application offloading. Based on various traffic scenarios, researchers study the efficiency of the MAO algorithm and show its performance in terms of rejected jobs and energy savings. First, the researchers consider the case where the application servers were placed systematically at the antenna's site. For a more realistic context of Mobile Cloud Computing, they extend the analysis by considering the case where the remote servers can be placed at different splitting points of the infrastructure. They assess by means of closed-forms fitting functions the performance of the MAO algorithm. Authors end this article with proposing an optimized applications servers placement.

The quest for energy traps in the CP43 antenna of photosystem II

To identify energy traps in CP43, a subcomplex of the photosystem II antenna system, site energies and excitonic couplings of the QY transitions of chlorophyll (Chl) a pigments bound to CP43 are computed using electrostatic models of pigment–protein and pigment–pigment interactions. The computations are based on recent crystal structures of the photosystem II core complex with resolutions of 1.9 and 2.1Å and compared to earlier results obtained at 2.9Å resolution. Linear optical spectra (i.e., absorption, linear dichroism, circular dichroism, and fluorescence) are simulated using the computed excitonic couplings, a refinement fit for the site energies, and a dynamical theory of optical lineshapes. A comparison of the obtained root mean square deviation of about 100cm−1 between directly calculated and refined site energies with the maximum range of about 350cm−1 of directly calculated site energies shows that the combined quantum chemical/electrostatic approach provides a semi-quantitative agreement with experiment. Possible reasons for the deviations are discussed, including limits of the electrostatic models and the lineshape theory as well as structural alterations of CP43 upon detachment from the core complex. Based on the simulations, an assignment of the two low-energy exciton states A and B of CP43, that where observed earlier in hole burning studies, is suggested. State A is assigned to a localized exciton state on Chl 37 in the lumenal layer of pigments. State B is assigned to an exciton state that is delocalized over several pigments in the cytoplasmic layer. The delocalization explains the smaller inhomogeneous width of state B compared to state A observed in hole burning spectra, which is proposed to be due to exchange narrowing. The assignment of states A and B largely confirms our earlier suggestion that was based on a fit of linear optical spectra and electrostatic calculations using the 2.9Å resolution structure. Interestingly, for the latter structure, the site energy of Chl 37 is obtained closer to the refined value than for 1.9 and 2.1Å resolution. This is explained by a variation of the site energy due to the influence of lipids that might be different in the core complex and isolated CP43. To remove remaining uncertainties in the assignment of states A and B, target sites for mutagenesis experiments are proposed based on the electrostatic computations. In particular, it is suggested to mutate Trp C63 close to Chl 37 to probe the identity of state A and to mutate Arg C41 close to Chl 47 to probe state B.

Fully Passive Remote Radio Head for Uplink Cell Densification in Wireless Access Networks

A novel remote radio head (RRH) concept for fully passive radio access network (RAN) plants is demonstrated for short-range wireless networks. The joint transmission of data and energy through the optical fronthaul of RANs enables on-demand network densification through the deployment of distributed cells with low-complexity and low-power antenna sites along a passive optical network without electrical supply. The feasibility of the proposed RRH is demonstrated in uplink direction, employing low-noise amplification and analogue radio-over-fiber transmission over multimode fiber. Remote powering through the optical fronthaul is realized at a feed power of 120 mW.

DGPS 기준국 사이트 환경에 따른 안테나 성능 모델링 해석

본 논문에서는 DGPS 단축형 모노폴 안테나와 안테나 사이트 환경을 모델링하여 안테나 주변 환경에 따른 안테나 성능을 분석한다. DGPS 기준국 안테나의 성능 해석을 위한 모델링을 해석하고 대지 도전율이나 전파 장애물에 의한 안테나 성능을 모의 분석하여 DGPS 안테나 설치에 요구되는 사이트 환경을 정립한다. 일정한 접지 면에 적정한 방사형 접지를 갖는 안테나 사이트는 대지 도전율이나 전파 장애물로 인한 안테나 정합회로에 대한 영향은 적으나, 방사 효율 영향은 크게 나타난다. 안정된 DGPS 서비스를 위해서는 안테나 사이트의 양호한 대지 도전율이외에 주변에 전파 장애물이 없는 평탄한 안테나 사이트가 중요하다. Based on the modeling of DGPS antenna and antenna site environment, the DGPS short-monopole antenna performance according to the antenna surrounding environment are analyzed in this paper. The DGPS antenna site modeling that considers the ground conductivity and radio wave obstacles is performed and the general requirements for DGPS antenna site are proposed. In case of antenna site with proper radials on the ground plane of the fixed scale, the effect for antenna matching network due to the ground conductivity and radio wave obstacles is small but the impact on the radiation efficiency is large. To provide the stable DGPS service, it is important to install the DGPS antenna on the flat ground plain with good conductivity and without radio wave obstacles.

A novel single feed of circular polarized antenna and open area test site measurements for 2.4 GHz application

ABSTRACTA novel single feed of the truncated edge circular polarized array antenna for 2.4 GHz applications with high gain is analyzed and proposed. The presented circular polarized antenna is comprised of four patches as its radiating elements and fed by a single coaxial connector at the ground layer. Dimension‐wise, the proposed antenna is designed with compact size of 56 × 69 × 1.6 mm3. It is notified that 45° of patches' truncated edge, 45 mm element spacing of Y‐axis, and 39.5 mm element spacing of X‐axis collectively contribute to the circular polarization capability. The prototype of the antenna has a right‐hand circular polarization with an axial ratio of 2.019 in particular of 2.4 GHz. Additionally, the similarity patterns of E‐plane and H‐plane of the antenna prove its circular polarization capability. Further, the proposed antenna seems to have an omnidirectional pattern eventhough using a full ground plane and improved the effective coverage angle. With the measured gain of 5.35 dB and the reflection coefficient of −14.16 dB, the proposed antenna has big potential for Wi‐Fi and biomedical application. The antenna prototype performance is verified, and the experimental result is presented and discussed. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1337–1344, 2014

Multiphysics design methodology for photonic-based phased array antennas

This work proposes a multiphysics design methodology for photonic-based phased array antennas. It is based on the use of circuital and full wave electromagnetic solvers in conjunction with an optical numerical tool. To illustrate the proposed methodology, it is presented the design of a photonic beamformer for a phased array based on four patch antennas operating at 5.8 GHz. The array has been numerically evaluated using a 50-km radio over fiber system, responsible to transmit the RF signal from the Central Office to the Remote Antenna Site. It has been used the following pieces of software: VPI Transmission Maker for optical domain simulations, Designer and HFSS from ANSYS for electrical domain simulations. The last two are easily integrated, as the same company had produced them. Conversely, it was necessary to create an efficiency interface for enabling the integration between VPI Transmission Maker and them. This interface enables the integration between the optical domain at hundreds of THz and the electrical domain at some GHz. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:838–843, 2014

OFDM/WDM PON With Laserless, Colorless 1 Gb/s ONUs Based on Si-PIC and Slow IC

We introduce a next-generation long-reach access optical network (35 dB loss budget +2  dB margin) delivering up to 40G/40G per passive 1∶256 optical distribution network, supporting symmetrical 1  Gb/s rates per home user or up to 40  Gb/s for business users (e.g., enterprises, antenna sites). The proposed system is based on a novel spectrally efficient orthogonal frequency division multiplexing/wavelength division multiplexing OFDM/WDM architecture symmetrically using 16-QAM OFDM polarization diversity in both the downstream and upstream in order to serve low-cost energy-efficient symmetric 1  Gb/s optical network units (ONUs), which are self-coherent, laserless, colorless, and tunable-filter-free. Each ONU comprises a standard semiconductor optical amplifier (SOA), a silicon-based photonic integrated circuit (PIC), and mixed-signal electronic integrated circuits (ICs) performing the signal processing at a relatively slow rate as compared with the overall passive optical network (PON) throughput: digital to analog converters (DACs) and analog to digital converters (ADCs) at 417  MS/s for the home user ONUs.

Squashed Single Feed Circularly Polarised Micro strip Antenna for Navigation Applications

A squashed single-feed circularly-polarized (CP) wide beam microstrip antenna is projected for CNSS application. The antenna is intended by a double-layer arrangement, comprise a round space with two rectangular stubs the length of the width route and a sponging ring accurate more than it. To gather the uplink and downlink band of the scheme, a dual-band circularly polarized antenna should be encouraged and applied. In the meantime, due to the little number of CNSS satellites, the enormous gain of terminal antenna for small altitude is necessary. The third generation message scheme has been formally implement in our saleable. With the increasing difficulty of the scheme, it is straight away need to solve the multipath signal degradation and reduce the numeral, the cost and the site of antenna. For immediately gathering these supplies, the composite dual-polarized base location transmitter has been the prospect trend. The antenna is considered with a doublelayer arrangement, comprise a round patch with two rectangular stubs along the distance route and a parasitic ring right above it. The resonance frequency and the CP character are mostly prohibited by the round patch and the rectangular stubs, correspondingly. The perpendicular HPBW could be widening by the parasitic ring. New results show that the deliberate vertical HPBW is around 140 and the deliberate out-of-roundness for the horizontal radiation pattern is only 1.1 dB. In addition, it could uphold good inconspicuous character.

Comprehensive Approach Toward the Feasibility of Radio Over Fiber Technology for WiMAX Systems

To meet the explosive demands of high-capacity and broadband wireless access, modern cell-based wireless networks have trends, i.e. continuous increase in the number of cells and utilization of higher frequency bands. It leads to a large amount of Base Stations (BSs) to be deployed; therefore, cost-effective BS development is a key to success in the market. In order to reduce the system cost, Radio over Fiber (RoF) technology has been proposed since it provides functionally simple BSs that are interconnected to a central Control Station via an optical fiber. The well-known advantages of optical fiber as a transmission medium such as low loss, light weight, large bandwidth characteristics, small size, and low cable cost make it the ideal and most flexible solution for efficiently transporting radio signals to remotely located antenna sites in a wireless network. In addition to its transmission properties, the insensitivity of fiber optic cables to electromagnetic radiation is a key benefit in their implementation as the backbone of a wireless network. This paper will provide an overview of RoF technology, followed by the description of suitable architectures for the deployment of Worldwide Interoperability for Microwave Access (WiMAX) networks employing RoF systems. Main issues and challenges in the deployment of WiMAX employing RoF technology will be discussed in detail after reviewing some experimental and theoretical work. Furthermore, a simulation model for IEEE 802.16e is studied and simulation results are shown.

Everyday Landmarks of Networked Urbanism: Cellular Antenna Sites and the Infrastructure of Mobile Communication in Philadelphia

Harnessing the utility of mobile communication and the mobile Internet is a common, everyday aspect of the urban condition. The wireless connectivity these pocketable devices are produced through an electromagnetic overlay that emanates from cellular antenna and towers. These sites have a distinct if often overlooked presence in the urban landscape of the United States. Through fieldwork in Philadelphia, Pennsylvania, this essay examines the aesthetic impact of telecommunications network equipment such as cellular sites as a means of locating these sites as key socio-technical actors in one of the information and telecommunication infrastructures of contemporary, networked urbanism.

Challenges to radio over fiber (RoF) technology and its mitigation schemes – A review

For realization of future high performance integrated networks, broadband distribution and access networks and to meet the increasing demand of multimedia services with a guaranteed quality of service, RoF technology comes out as the most promising technology that combines the capacity of optical networks with the flexibility and mobility of wireless networks. Reduction in complexity at the antenna site, reduction in installation cost of access networks, possibility of dynamically allocation of radio carriers to different antenna sites, transparency and scalability are the few advantages of radio-over-fiber (RoF) technology. In this paper, we review the different challenges that limit the probable capabilities of RoF communication networks and different mitigation techniques to combat with these challenges to realize high-performance RoF links.

Broadband Access Using Wireless Over Multimode Fiber Systems

With the growing need for low cost wireless over fiber systems the use of multimode fiber (MMF) has become of greater interest. The well known advantages of optical fiber as a transmission medium such as low loss, light weight, large bandwidth characteristics and small size make it the most flexible solution for transporting radio signals to remotely located antenna sites where coverage is required. To provide reliable indoor cellular and wireless local area network (WLAN) coverage without dependence on the radio penetration from outside base stations, it is highly desirable that the same MMF infrastructure be used to carry additional services between the equipment room and the remote antenna units around the building. One of the main benefits of using the wireless over fiber technique is the inherent transparency to the transported wireless signals. This allows configuring the system for a range of both wireless and cellular services to be combined to transmit simultaneously. Hence, it is highly desirable to invest in a multiservice broadband remoting infrastructure which is capable of handling both current and future RF systems. In this paper we present an overview of some of the latest technologies for wireless over multimode fiber systems.

Effective area of the antenna of the RT-22 CrAO RI radio telescope

Based on the results of calibrator observations at 13.5-mm and 8.2-mm wavelengths in 1985 and 2005, the dependence of the effective area of the RT-22 CrAO RI antenna on ambient temperature and elevation was determined. The obtained results confirm a high quality of the RT-22 antenna at millimeter wavelengths. A high accuracy of the reflector surface makes it possible to observe at millimeter wavelengths right to 2 mm. At 8.2-mm wavelength, the effective area changes by no more than 5% when the antenna is reinstalled from the zenith to 15° elevation angle. Large antennas, intended to operate at maximum frequencies, should be built either taking into account the climatic conditions of the antenna sites or taking measures to provide thermal stability of the antenna.

Microgravity vertical gradient measurement in the site of VIRGO interferometric antenna (Pisa plain, Italy)

The site of the European Gravitational Observatory (EGO) located in the countryside near Pisa (Tuscany, Italy) was investigated by a microgravity vertical gradient (MVG) survey. The EGO site houses the VIRGO interferometric antenna for gravitational waves detection. The microgravity survey aims to highlight the gravity anomalies of high-frequency related to more superficial geological sources in order to obtain a detailed model of the lithologic setting of the VIRGO site, that will allow an estimate of the noise induced by seismic waves and by Newtonian interference. This paper presents the results of the gradiometric survey of 2006 in the area of the interferometric antenna. MVG measurements allow us to enhance the high frequency signal strongly associated with the shallow structures. The gradient gravity map shows a main negative pattern that seems related to the trending of the high density layer of gravel that was evidenced in geotechnical drillings executed along the orthogonal arms during the construction of the VIRGO complex. Calibrating the relationship between the vertical gradient and the depth of the gravel interface we have computed a model of gravity gradient for the whole VIRGO site, defining the 3D distribution of the top surface of this layer. This latter shows a NE-SW negative pattern that may represent a palaeo-bed alluvial of the Serchio from the Bientina River system.

Improving HSDPA Indoor Coverage and Throughput by Repeater and Dedicated Indoor System

The target of the paper is to provide guidelines for indoor planning and optimization using an outdoor-to-indoor repeater or a dedicated indoor system. The paper provides practical information for enhancing the performance of high-speed downlink packet access (HSDPA) in an indoor environment. The capabilities of an outdoor-to-indoor analog WCDMA repeater are set against a dedicated indoor system and, furthermore, compared to indoor coverage of a nearby macrocellular base station. An extensive measurement campaign with varying system configurations was arranged in different indoor environments. The results show that compared to dedicated indoor systems, similar HSDPA performance can be provided by extending macrocellular coverage inside buildings using an outdoor-to-indoor repeater. According to the measurements, the pilot coverage planning threshold of about −80 dBm ensures a 2500 kbps throughput for shared HSDPA connections. Improving the coverage above −80 dBm seems to provide only small advantage in HSDPA throughput. Of course, the pilot planning thresholds may change if different channel power allocations are used. In addition, network performance can be further improved by increasing the antenna density in the serving distributed antenna system. Finally, good performance of repeater implementation needs careful repeater gain setting and donor antenna siting.

On the applications of the space time premise when exploiting location diversity of multiple antenna sites

This paper presents novel techniques to exploit the spatial dimension and the space time (ST) premise in a Large Scale Communication Networks LSCN(s). These techniques are based on an encapsulation framework aimed at enforcing an artificial none line of sight (NLOS) condition. The framework integrates the spatially diverse multiple antenna sites (MAS); composing parts of an LSCN into joint transmission/reception systems. The location diversity of these MAS provides for exploiting the spatial dimension whether for multiplexing gain, diversity gain and/or array gain. Whereas multiplexing gain is best exploited in multi input multi output (MIMO) architectures to boost spectrum efficiency; diversity and array gains lend themselves to equally useful applications e.g., in VSAT technology; array/diversity gain can improve the uplink efficiency to satellite, diversity gain may resolve uncertainty issues in HF link, etc. This paper develops a framework for exploiting MIMO in a network to network communications. It also outlines possible applications of location diversity of MAS in LSCNs. Selected scenarios include terrestrial satellite networks, VSAT network topologies, HF communications and broadband global area networks (BGAN).

Occupational Exposure at Mobile Communication Base Station Antenna Sites

Occupational Exposure at Mobile Communication Base Station Antenna Sites

Radio-Over-MMF Techniques—Part II: Microwave to Millimeter-Wave Systems

Microwave to mm-wave radio carriers are commonly employed for creating high-capacity picocell wireless networks. Advanced radio-over-fiber (RoF) techniques can efficiently generate and transport such carriers, and deliver them to simplified antenna stations. As in in-building networks multimode fiber is predominantly used, adequate radio-over-multimode fiber (RoMMF) techniques are required to overcome the modal dispersion in multimode fiber links. The optical frequency multiplying technique is introduced; it is relatively simple to implement, yet it is shown to be robust against the modal dispersion, and it is able to generate very pure microwave carriers while requiring only moderate speed electronics. Thus, it can convey high data rates in comprehensive modulation formats on multiple-GHz carriers in MMF networks. It offers simultaneous operation at multiple radio standards, and capabilities for dynamic adaptation of the radio link parameters such as carrier frequency, transmit power, and other antenna site functions by means of an embedded control channel. Moreover, in combination with optical routing it enables dynamically adjustable network configurations for flexible wireless service delivery.

Experimental Results for the Multipath Performance of Galileo Signals Transmitted by GIOVE‐A Satellite

Analysis of GIOVE‐A signals is an important part of the in‐orbit validation phase of the Galileo program. GIOVE‐A transmits the ranging signals using all the code modulations currently foreseen for the future Galileo and provides a foretaste of their performance in real‐life applications. Due to the use of advanced code modulations, the ranging signals of Galileo provide significant improvement of the multipath performance as compared to current GPS. In this paper, we summarize the results of about 1.5 years of observations using the data from four antenna sites. The analysis of the elevation dependence of averaged multipath errors and the multipath time series for static data indicate significant suppression of long‐range multipath by the best Galileo codes. The E5AltBOC signal is confirmed to be a multipath suppression champion for all the data sets. According to the results of the observations, the Galileo signals can be classified into 3 groups: high‐performance (E5AltBOC, L1A, E6A), medium‐performance (E6BC, E5a, E5b) and an L1BC signal, which has the lowest performance among Galileo signals, but is still better than GPS‐CA. The car tests have demonstrated that for kinematic multipath the intersignal differences are a lot less pronounced. The phase multipath performance is also discussed.

Investigation of 3G radio network topologies considering performance and exposure aspects

Abstract. Five different radio network topologies, in the following referred to as "scenario", have been analyzed with regard to their capability to cover a medium size city with 3G mobile services. T-Mobile launched this study to assess different radio network topologies in terms of exposure. Thus, the main focus is to examine if, for exposure reasons, a medium size city can be covered with outer-city located sites. The radio network topologies discussed in this paper can generally be divided into two categories: In category one, the sites are located in the city, and in the other, the sites are located outside of the built-up area. In both cases the number of sites per scenario varies, and additionally the antenna height and site distance to the built-up area vary for the second category. The investigations are performed with a ray optical propagation model based on 3-D building data and a dynamic 3G network simulator. A mix of four services and a realistic spatial traffic distribution based on land usage is assumed. The performance of the scenarios, assessed by the evaluation of coverage and capacity, is examined together with the exposure. It is shown that network topologies with sites located only outside the city are not an adequate solution due to capacity constraints and coverage problems with high data services. A promising network topology is a reduced set of inner-city sites with higher order sectorization.