Showing papers on "GSM frequency bands published in 2013"

Genetic-based design of a tetra-band high-efficiency radio-frequency energy harvesting system

Abstract: In this study, we exploit genetic algorithms to design a rectenna required to harvest ambient radio-frequency (RF) energy from four different RF bands in critical (ultra-low power) conditions. For this purpose a set of multi-resonant annular-ring patch antennas are pixel-wise described inside an electromagnetic simulator to provide the `population' of individuals among which the genetic tool is able to select the most adapted one with respect to the design specifications. The further use of circuit-level non-linear simulation tool, based on Harmonic balance technique, allows the rigorous multi-band design of the whole rectenna system in RF stationary conditions at several received power levels. The result is a novel compact, lightweight and highly efficient tetra-band rectenna, able to harvest RF energy from GSM 900, GSM 1800, UMTS and WiFi sources available in the ambient. At these frequency bands high radiation efficiency is desired as an essential prerequisite for optimally handling very low-power densities. Very good agreement with measurements of both the radiating and rectifying designs is demonstrated in real office scenarios. Finally the rectenna is connected to a power management unit and the resulting assembly is tested in terms of stored energy while harvesting from a mobile cell-phone call.

Low-SAR, Miniaturized Printed Antenna for Mobile, ISM, and WLAN Services

Abstract: Recently, the mobile handsets support both the mobile and wireless LAN services. Thus, our target is to introduce a new antenna that supports both services. The antenna operates for most of the mobile applications such as the GSM 850, GSM 900, DCS 1800, PCS 1900, UMTS 2100, and most of the LTE bands, especially the low-frequency LTE 700 band. The antenna also supports the WiMAX, wireless local area network (WLAN), and the Industrial, Scientific, and Medical (ISM) bands. The antenna not only has a compact size, but also it supports a low specific absorption rate (SAR) radiation at all the operating frequencies. It consists of a monopole, a meander line, and an electromagnetic band-gap (EBG) structure. In order to cover the low frequency bands, a meander line is utilized due to its compact size, but unfortunately it is a narrowband antenna that is difficult to cover both LTE700 and GSM 900 bands. The solution stems from the use of an EBG structure that widens the band to cover the two low frequency bands and to reduce the maximum SAR. The higher frequency bands are supported by both the monopole and the meander line since they acts as traveling-wave antennas at the high frequency bands. The antenna meets three challenging parameters: the compact size, the multiband operation including the low frequency bands, and the low SAR radiation. Good agreement is found between the experimental and the simulated results.

Antennas and circuits for ambient RF energy harvesting in wireless body area networks

Abstract: In this paper, we identify the spectrum opportunities for radio frequency (RF) energy harvesting through power density measurements from 350 MHz to 3 GHz. The field trials have been performed in Covilha by using the NAKDA-SMR spectrum analyser with a measuring antenna. Based on the identification of the most promising opportunities, a dual-band band printed antenna operating at GSM bands (900/1800) is proposed, with gains of the order 1.8-2.06 dBi and efficiency 77.6-84%. Guidelines for the design of RF energy harvesting circuits and choice of textile materials for a wearable antenna are also discussed. Besides, we address the guidelines for designing circuits to harvest energy in a scenario where a wireless body area network (WBAN) is being sustained by a TX91501 Powercasf® RF dedicated transmitter and a five-stage Dickson voltage multiplier responsible for harvesting the RF energy. The IRIS motes, considered for our WBAN scenario, can perpetually operate if the RF received power attains at least -10 dBm.

A fully-autonomous integrated rf energy harvesting system for wearable applications

Abstract: In this paper we introduce a complete system architecture of a textile-based rectenna loaded by a novel power management platform able to be autonomously activated by ambient RF energy harvesters An integral design approach of the system blocks is carried out to provide the actual nonlinear behavior of the rectenna output, which is a function of the operating frequencies and power levels, as the DC-DC converter input The RF properties of the textile rectenna are computed by nonlinear techniques with textile materials and antenna layout numerically characterized by means of EM simulations A novel integrated power converter is adopted It is equipped with a start-up circuit and an energy storage unit and it is designed by microelectronic technology Energy autonomy of the entire system, including a battery-less activation is expected for RF available power levels as low as -15 dBm The system operation is computed with the wearable rectenna recovering RF energy upon user request from GSM 900, GSM 1800 and WiFi sources

A study on Path loss Analysis for GSM Mobile Networks for Urban, Rural and Suburban Regions of Karnataka State

Abstract: To establish any mobile network system, the basic task is to foresee the coverage of the proposed system in general. Many such different approaches have been developed, over the past, to predict coverage using what are known as propagation models. In this paper, measurement based path loss example and shadowing parameters are applied on path loss models. Here, the measurements are carried out in urban, rural and suburban areas considering non-line-of-sight terrains with low elevation antennas for the transceiver (Tx) and receiver (Rx)[5]. The impact of multipath are more emphasized in the rural context. This causes higher probability of RF signal errors. On the basis of observation and with the help of clutter, we can present models which give better understanding for urban, rural and suburban regions in Karnataka state at 940 MHz GSM frequency[5],[26][13].

Two days of European spectrum: Preliminary analysis of concurrent spectrum use in seven European sites in GSM and ISM bands

Abstract: We report initial results from 48 hour spectrum occupancy measurement campaign that was done in time-correlated fashion in seven different European locations. We give a description of the measurement campaign and provide results from our preliminary analysis of overall duty cycle in the frequency range 110-3000 MHz. The paper particularly focuses on traffic and duty cycle patterns in GSM 900 and GSM 1800 bands. For the sake of completeness, we also discuss ISMband utilization in two of our measurement sites. We show that spectrum utilization is generally low, but that variance between frequency bands and locations is significant, which means that any statistical claims on occupancy statistics need to be done carefully before regulatory claims are made.

Wireless power supplying flexible and wearable systems

Abstract: In this paper we first overview CAD techniques for the optimization of energy harvesting and storage systems designed to exploit EM sources available in the ambient. For a successful operation an accurate prediction of the minimum received power is needed to ensure the rectifier turn-on and the start-up of the energy storage control circuit. The proposed method is based on a first step dedicated to the simulation/optimization of the rectenna nonlinear regimes to determine reference values of the received signals. The second step is carried out in the time domain and is devoted to the optimization of the power management unit with the goal of dynamically keeping the rectenna at its optimum loading conditions. During this process the dispersive behavior of rectenna is accurately accounted for. The procedure validation is then discussed for a textile multi-layer multi-frequency rectenna using fabric for both the substrates and the metallic layers. The presented system is thought to recover RF energy upon user request from GSM 900, GSM 1800 and WiFi sources.

Low SAR, Compact and Multiband Antenna

Abstract: This paper proposes a new mobile handset antenna structure to reduce the value of the speciflc absorption rate (SAR) and to cover most of the mobile operating bands and other wireless applications. The covered bands are the GSM 900, DCS 1800, PCS 1900, UMTS 2100, and most of the LTE bands. Furthermore, it covers the ISM, WiMAX and the WLAN bands. The electromagnetic radiation in the direction of the human head is reduced via the use of electromagnetic band gap structure (EBG). The antenna is constructed from a monopole and a meander line. The operating bands ranges from (850{1030MHz) and (1.71{7.8GHz). Moreover, the flrst band of the antenna can be tuned by using various meander line lengths or by adjusting the spacing between the monopole and the meander line, while the second band can be tuned by adjusting the monopole length or the meander line area. The antenna volume is 20£20£1:5mm 3 (0.6cm 3 ), so the proposed antenna is suitable for many wireless handheld devices. The simulation results are compared to the experimental measurements and a good agreement is observed.

High time-resolution spectrum occupancy model for testing of cognitive radio devices

Abstract: The ubiquitous problem of radio spectrum scarcity caused by ever-increasing traffic, e.g. in mobile communications, demands measures. One approach would be secondary use of spectrum by radio devices with cognitive abilities employing dynamic spectrum access. In order to avoid interference with the primary use of the spectrum, such cognitive devices must be thoroughly tested. In this paper, we present a high time-resolution model of spectrum occupancy, stemming from the activity of primary users, for testing purposes. The proposed model is based on a few statistical parameters and includes a novel parameter adaptation procedure that improves the accuracy of current models significantly. The intended use of the model is over-the-air testing of cognitive devices, for instance for prototyping purposes, e.g. evaluation of the achievable performance, or for conformance testing. The model parameters are extracted from measurement data in the GSM 900 downlink band obtained at the Ilmenau University of Technology campus. However, the modeling approach is not restricted to GSM 900 but lends itself to other bands and radio technologies, too.

Specific Absorption Rate evaluation in apple exposed to RF radiation from GSM mobile towers

Abstract: Specific Absorption Rate (SAR) is a measure of the rate at which energy is absorbed by an object when exposed to an electromagnetic field. SAR evaluation at different human organs due to cell phone radiation is very common today. On the other hand, none has yet considered that the plants, fruits and crops get exposed to RF radiation from cell phone towers 24 hours a day without any shielding. Therefore, the purpose of this research paper is to evaluate SAR in apple fruit (in tree) due to radiation coming from cell phone towers in GSM bands at controlled and public exposure zones. SAR has been evaluated in an apple with CST MICROWAVE STUDIO (CST-MWS) simulator based on Finite Integration Technique (FIT).

Multi-frequency plane printed antenna comprising protruded floor and applied to mobile terminal

Abstract: The invention discloses a multi-frequency plane printed antenna comprising a protruded floor and applied to a mobile terminal and belongs to the technical field of mobile terminal antennas The multi-frequency plane printed antenna is characterized in that two resonance structures, namely a simulation branch and a parasitism land branch are utilized to select and combine all resonance modes which are simulated so as to obtain broadband and multi-frequency characteristics A coaxial probe feeding manner is utilized to improve the reliability of test results, and impedance matching is performed by loading an adjusting piece In addition, with the protruded floor structure, under the condition that acceptable antenna performance is ensured, placing spaces are provided for electronic equipment such as a camera, a loudspeaker, a data interface, a power supply and an earphone interface, wherein the electronic equipment possibly needs to be placed The area of a clearance zone occupied by the multi-frequency plane printed antenna on a circuit board is only 15mm*283mm, a -6dB impedance bandwidth of the multi-frequency plane printed antenna can effectively cover work frequency bands of GSM 850, GSM 900, DCS, PCS, UMTS, LTE 2300, 24-GHz WLAN, LTE 2500 and the like

Broadband dual-polarized antenna unit and broadband antenna

Abstract: The invention relates to a broadband dual-polarized antenna unit which is arranged on a metal reflective board, and comprises two pairs of polarized dipole radiation units orthogonally arranged, each dipole radiation unit is arranged on the metal reflective board by a balun, and the positions where the dipole radiation units are connected with the balun are in the same one reference plane; each dipole radiation unit comprises two unit arms symmetrically fixedly arranged on the balun, one ends of the unit arms are fixedly connected with the balun, and the other ends of the unit arms are provided with board like pieces perpendicular to the reference plane; and projections of the unit arms on the reference plane enclose a centrosymmetric polygonal or circle. The broadband dual-polarized antenna unit is simple in structure, easy to manufacture, and suitable for batch production, has the advantages of high performance and broadband, and is especially applicable to mobile communication systems of GSM (Global System For Mobile Communication) 800, GSM 900, CDMA (Code Division Multiple Access) 800, LTE (Long Term Evolution) 700 and the like with 600-1000MHz.

A wireless sensor netwok for RF characterisation of buildings

Abstract: This paper presents a wireless sensor network (WSN) designed to assist in the characterization of radio propagation within buildings. The WSN comprises a number of 2.4GHz Zigbee nodes which measure RF power within the building and transmit these values to a central controller to record the values. Tunable band-pass filters (BPF) are used to select the frequency at which the RF signals are measured. In this paper two systems are presented, one for measuring signal strength within the Trans-European Trunked Radio (TETRA) band (380M-420MHz), the other within the AMPS and GSM 900 bands (806MHz-960MHz). Received Signal Strength Indicator (RSSI) of the 2.4GHz Zigbee signal are also sampled and recorded.

Assessment of Spatial Exposure to RF Radiation due to GSM 900 and GSM1800 - A Case Study of UCH, Ibadan, Nigeria

Abstract: An assessment of radiofrequency exposure due to GSM 900 and GSM 1800 was carried out at 30 strategic locations in the University College Hospital (UCH), Ibadan with a frequency selective spectrum analyzer (SPECTRAN HF 60105). The Spectrum analyzer was coupled to a calibrated Omnidirectional antenna to obtain a spatial power density for each location. The mean power densities of 38.37µW/m 2 and 8.68µW/m 2 and maximum power densities of 212.40µW/m 2 and 67.40µW/m 2 were obtained for GSM 900 and GSM 1800 respectively. The standard deviation of 51.3 µW/m 2 and 14.90µW/m 2 were also obtained for GSM 900 and GSM 1800 respectively. GSM 900 and GSM 1800 respectively show compliance level of 0.0047% and 0.00075% with the ICNIRP reference level. Keywords - power density, GSM, radiofrequency, exposure, spectrum analyzer

Path Loss Model Tuning at GSM 900 for a Single Cell Base Station

Abstract: Mobile communications has become an everyday commodity. In the last decades, it has evolved from being an expensive technology for a few selected individuals to today’s ubiquitous systems used by a majority of the world’s population. Imprecise propagation models lead to networks with high co-channel interference, as well as power waste. This study aims to adapt a propagation model in the city of Nablus (Palestine) for a GSM frequency band. This study helps to design better GSM networks for the city in spite of the geographical and frequency limitations. The modification is accomplished by investigating the variation in path loss between the measured and predicted values, according to the propagation model for a specific cell. The results from a simulation model and measured data was compared and analyzed. Bertoni-Walfisch model, without tuning, gave the best results with a mean error of 1.426 dB, which is much less than the mean error obtained by the Standard Macrocell model, 10.91 dB, which is used by a local mobile operator. The two models have been tuned to fit measured data for GSM-900 in the city of Nablus. This is a vital step in cell planning and rollout of wireless networks. To confirm the superiority of Bertoni-Walfisch, a comparison between Bertoni-Walfisch and Standard Macrocell model in terms of Standard Deviation and Mean Error (RMSE). DOI: 10.4018/jmcmc.2013010104 48 International Journal of Mobile Computing and Multimedia Communications, 5(1), 47-56, January-March 2013 Copyright © 2013, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. strength. This will make the model more precise in receiving wireless signal predictions (Yang, Shi, 2008). Operators utilize special planning software to undertake propagation model tuning, such as ASSET and ATOLL (Mingjing, Wenxiao, 2008), (Yang, Fang, Yongyu, Dacheng, 2007). The local cellular communication operator uses ASSET software (AIRCOM International Ltd., 2007) which is based on modified Hata model. 1.1. Terrestrial Description of Nablus City The city of Nablus cast narrow streets and moderately high buildings, the buildings heights vary between 9 and 12 m within the old city and city center. Most of the buildings are mass of concrete, rock-like blocks, and bricks. Furthermore, in terms of landscape, Nablus has a particular characteristic of having a large number of squares (small open areas). Extensive experimental tests were performed in the geographic area of Nablus and especially in the city center to investigate the channel propagation behavior in different directions relative to the streets. The results of those measurements were used to define the standard deviation, mean error and RMSE to enhance our understanding of wave propagation in the city. 1.2. Frequency Reuse Problem in Drive Test Frequency reuse is a technique where frequencies and channels within a communication system is reused to improve capacity and spectral efficiency. Frequency reuse in mobile cellular systems requires each cell to maintain a frequency that is enough far away from the frequency in the adjacent cell to eliminate the interference problems. A local operator requires frequency reuse for many sites. For example, Nablus has around seventy sites with each site containing two to three cells while the operator has twenty-four channels from GSM-900 band. The first twelve channels are BCCH (Broadcast Control Channel), and the last twelve are traffic channels due to certain agreements. Therefore, frequency reuse is an urgent need in Nablus cellular networks. The paper is organized such that Section 2 presents the measurement environment. Section 3 reviews some propagation models and the path loss concept. Section 4 discusses the standard macrocell model tuning. Section 5 describes Bertoni-Walfisch model tuning and Section 6 concludes the findings.

Assessment of quasi-permanently vacant channels in mobile communication bands for cognitive radio

Abstract: Basis of cognitive radio is to exploit unused frequency channels in licensed band. Recently standardised IEEE 802.22 set of cognitive radio protocols envisages fixed and nomadic receivers at below 800 MHz bands. Radio link design for this cognitive radio consider that the channels are available only dynamically to secondary users. Scanning period is thus embedded in link layer control as overhead and reduces overall efficiency of cognitive radio technology. For mobile receivers, availability of permanent channels for radio link control is essential for in-band signalling. Existing mobile communication system uses CDMA 800, GSM 900, GSM 1800 and WCDMA 2000 MHz bands for which approximately 1/8th of the band capacity is used for in-band signalling. Present work provides an assessment of vacant channels in mobile communications range which were permanently available at the time of measurement. The study used conventional Radio frequency scanners available for different bands and dedicated engineering handsets for tracking active frequencies. Observations were taken at six different cities of India with population ranging from 1.5 million to 6.6 million. The tests were performed with assemblies carried in a vehicle and across the length and breadth of each city. The allotment of frequencies by Frequency Regulatory Authority to local mobile operators along with the frequency bands reserved for further distribution were also considered. The experimentally collected data were analysed using RF analysis software and spread sheet database. An analysis of the collected data lead to arrive at the conclusion that more than 1/8th part of resources of each band are nearly permanently vacant which is enough to design in-band common control signalling methods for cognitive radio.

Method for prolonging standby time of GSM (Global System for Mobile Communications)/TD (Time division) mode terminal, and terminal

Abstract: The invention provides a method for prolonging standby time of a GSM (Global System for Mobile Communications)/TD (Time division) mode terminal, and a terminal, wherein the method comprises the steps of: after being started-up, selecting a GSM mode network cell for lingering; receiving a packet switching (PS) business demand after being lingered at the GSM mode network cell, selecting a TD mode network cell to be lingered; and after executing the PS business in the TD mode network cell, quitting the lingering in the TD mode network cell. According to the method and terminal, the electricity consumption of the GSM/TD mode terminal can be reduced.

An indoor to outdoor propagation model at gsm 900 gsm1800 and cdma2100

Abstract: An empirical indoor to outdoor propagation model has been improved based on empirical techniques. Improved model includes building structures such as number of walls, position of windows and the affect of frequency. Proposed model is valid for GSM 900, GSM 1800 and CDMA 2100. Theory and measurements are in tracking each other at CDMA2100 and GSM frequencies by at most 6dB deviation. Generated model can easily be used for outdoor coverage predictions and interference capability based on indoor antennas, especially at CDMA

Compact planar inverted-F antenna for mobile RF energy scavenging system

Abstract: With a promising future for generation of electricity to power electronics, RF energy scavenging has become a matter of significant interest in recent years. In this paper, a small-size printed planar inverted-F antenna (PIFA) is designed dedicated for compact mobile RF energy scavenging system to extract power from ambient RF energy. The proposed PIFA has its working frequencies at about 900 MHz and 1800 MHz to form lower and upper band that cover GSM 900 and DCS 1800 respectively, yet it only occupies a small printed area of 20×40 mm2 on the system circuit board. Power around -15 dBm is received by proposed antenna at distance of 500m from base station which reveal reasonable performance for RF energy scavenging at moderate distance.

Transmit-receive cable sharing POI (Point Of Interface)

Abstract: The utility model discloses a transmit-receive cable sharing POI, comprising a cabinet, a combiner and jumper wires. Seven systems, i.e., China Mobile GSM 900, China Telecom CDMA 800, China Mobile DCS 1800, China Unicom DCS 1800, China Mobile TD-SCDMA, China Mobile LTE and China Unicom WCDMA, are included. The transmit-receive cable sharing POI is low in loss, port isolation reaches more than 80 dB, and interference among signals of different systems can be avoided; and the die-casting aluminum cabinet up to 3U standard is employed, and the structure is safe and reliable and easy for construction and installation. The POI of the utility model including seven systems employs waterproof design, which can be applied to indoor and outdoor places including large buildings, tunnels, stations, and government or enterprises office buildings. Most frequency ranges, including 2G and 3G frequency ranges, in the prior mobile communication are covered, so that market requirements can be better satisfied.

Five-system eight-frequency combiner

Abstract: The utility model relates to a multi-system multi-frequency combiner for mobile communication, especially to a five-system eight-frequency combiner, which combines signals in eight different frequencies of five systems including CDMA 800, GSM 900, DCS 1800, TD-SCDMA and CDMA 2000, and outputs and covers the signals The five-system eight-frequency combiner comprises five input ends and one output end, and employs resonant cavity cross-coupling technology and public tap-coupling technology, so that the combiner is easy to debug, and mass production of the combiner is easy The combiner covers most frequency ranges of prior mobile communication, integrates 2G and 3G technologies of mobile communication, and is low in device loss According to the combiner, isolation degree can reach as high as 80 dB, interference between different systems can be avoided, and requirements for constructing the 3G system at present can be well satisfied

Four-frequency multimode electrically-tuned antenna

Abstract: The utility model relates to the technical field of antenna equipment, and specifically relates to a four-frequency multimode electrically-tuned antenna. The four-frequency multimode electrically-tuned antenna comprises a first reflecting plate and a second reflecting plate, wherein the edge of the first reflecting plate is in insulated connection with that of the second reflecting plate through a connecting piece; GSM 900 signal antenna array units and GSM 1800 signal antenna array units are installed on the front surface of the first reflecting plate; and intelligent antenna arrays, which are capable of processing TD-SCDMA signals and TD-LTE signals at the same time, are installed on the front surface of the second reflecting plate. Based on a traditional base station antenna and an intelligent antenna, the four-frequency multimode electrically-tuned antenna combining the traditional base station antenna with the intelligent antenna is achieved by means of reasonable optimization of resource allocation, so that compatibility of a communication system is improved, the number of base stations of a mobile operator and the complexity of network planning are reduced, and the construction cost of the base stations of the mobile operator is reduced.

Study on the appropriate dimensions and position of slots and notches in the ground plane of planar monopole handset antenna for bandwidth enhancement

Abstract: A slotted ground plane structure combined with a multiband planar monopole handset antenna for bandwidth enhancement and resonant modes tuning is presented. By simply inserting intelligent modifications using slots and notches to the system ground plane of an internal multiband handset antenna, a significant improvement in the bandwidths of lower bands LTE 700/GSM 850/GSM 900 and upper bands GSM 1800/1900, UMTS, LTE 2300/2500, WiMAX 3500, WLAN 2400/5200/5800 is achieved. The influences of the proposed slots and notches with different positions and dimensions on antenna performance are analyzed by means of simulations and parametric studies. Results show that the proposed ground plane modifications have improved the handset antenna performance to cover 12-band standard operations successfully.

FDTD Computation of Sar Distributions in Human Head for Mobile Phones

Abstract: The influence of radio frequency (RF) field orientation on specific absorption rate (SAR) in a human head is investigated in this paper. The amount of temperature raised in Human Head due to Mobile Phone usage with different frequency range is analyzed using a versatile electromagnetic field simulator based upon the Finite-Difference Time-Domain method (FDTD).The harmful effects of recent unbranded mobile phone is compared with the Branded Mobile Phones. This paper investigates the harmful effects of both Branded and Unbranded Mobile Phones for various frequency range and the result shows that the usage of Unbranded Mobile Phone will cause greater damage to brain cells when compared with Branded Mobile Phones. where E is the amplitude of electric field (V/m), σ is the conductivity (S/m), and ρ is the mass density of thetissue. In this paper, we present a finite-difference time- domain (FDTD) calculation of the specific absorption rate (SAR) in two-dimensional human head model at GSM 920 MHz, 835MHz and 1.900GHz radiation. The head model is exposed to an incident plane wave. The FDTD code is implemented using the EMPIRE XCcel Software. Simulation results indicate that the SAR value is minimum for GSM 835MHz when compared with other GSM frequency range.

Sound-light alarm theft-proof device of transformer based on Internet of things

Abstract: The utility model discloses a sound-light alarm theft-proof device of a transformer based on the Internet of things, which comprises a sound-light alarm, a three-phase input power supply and judging circuit, a signal input and output end, a main processing chip, a GSM wireless communication module and a storage battery. The main processing chip is respectively and electrically connected with the three-phase input power supply and judging circuit, the signal input and output end, the GSM wireless communication module and the storage battery. The sound-light alarm is electrically connected with the output end of the signal input and output end. The GSM wireless communication module is provided with an antenna. The storage battery is connected with a temperature switch. The three-phase input power supply and judging circuit, the signal input and output end, the main processing chip, the GSM wireless communication module, the storage battery and a charging switch are arranged in an aluminum alloy control cabinet. The outside of the aluminum alloy control cabinet is provided with heat-radiating grills. Wireless networks of GSM 900 MHz, 1800 MHz and 1900 MHz can be utilized by the sound-light alarm theft-proof device, and the alarm operation of the device is not limited by the distance.

Miniaturized 3D multi-frequency antenna

Abstract: The present invention provides a miniature three-dimensional multi-frequency antenna which can cover eight LTE specification bands. The miniature three-dimensional multi-frequency antenna is a simple loop metal microstrip antenna architecture appropriately configured with a breakpoint in a closed path, forming a cutoff type loop antenna to generate a lower frequency resonance mode. In addition, redesigned is a dual coupled feeding structure with its size controlled, such that four resonance modes can be excited to form two wide impedance bands in the low band and high band respectively, so as to successfully cover LTE 700, GSM 850, GSM 900, DCS, PCS, UMTS, LTE 2.3G, and LTE 2.5G, which are eight desirable specification bands, and to effectively reduce the size of the antenna.

High-performance GSM frequency selection ICS repeater

Abstract: The utility model discloses a high-performance GSM frequency selection ICS repeater which comprises a first transmit-receive antenna, an analog down converter, a digital module, an analog up converter and a second transmit-receive antenna, which are connected in order, wherein the digital module comprises an analog to digital converter (ADC) module, a DDC module, a noise self-adaptive offset module, a DUC module and a digital-analog converter (DAC) module, which are connected sequentially. The noise self-adapting offset module comprises a peripheral circuit reducing algorithm complexity and a self-adaptive filtering algorithm module capable of realizing improved IQRD-RLS algorithm, wherein the peripheral circuit comprises a first filter, a second filter, a third filter, a fourth filter, a first extraction module, a second extraction module, an interpolation module, a subtracter and a shifting register. The high-performance GSM option ICS repeater adopts a streamline improved IQRD-RLS algorithm, is fast in convergence rate, good in convergence effect and particularly suitable for a GSM system, and has small influence on performance when characteristic value diffusance is large.

Širokopásmový dělič výkonu pro pásma mobilních komunikací

Abstract: This document is focused on design of symmetrical wideband splitters, which are determined for distribution GSM (Global System for Mobile Communications) signals from one common antenna to two receivers. At the present time, GSM bands with for example LTE (Long Term Evolution) and others include frequencies in two bands, approximately from 0.81 GHz to 0.956 GHZ and from 1.71 GHz up to 2.62 GHz. That is exactly why this complex design of splitter represents wideband solution. This paper contains fundamental theory for designing of wideband splitter and simulated and measured parameters of the optimized splitter in CST Microwave Studio. Designed divider has been also analyzed by the worst case method. Obtained S parameters, such as transmission, isolation or reflections are discussed in the closing part of this paper.

The Number continuity service, Part I GSM Satellite phone

Abstract: Mobile Number Portability is now a widely used service allowing users to keep their number if they change their subscribed operator. It was first deployed in Hong-Kong (1999). « Number Continuity » corresponds to the same service but with the switch to another technology, because the subscribed main terminal does not have coverage. The new terminal may be a PC, a smartphone / WiFi, a “satphone”, a GSM phone if the main one is CDMA, with (almost) the same service transparently. Making calls or SMS with its normal CLI shown, receiving calls, SMS, MMS to his normal GSM number (unlike « Skype »). This article explains the GSM satphone number continuity implementation. The Geostationnary and Low Earth Orbit characteristics are presented as well the consequences of orbit drifts for which the exact computation is given based on the formal integration of Kepler's area law. The handover implementation and cases for the satellite service are explained. The constellation and services of the main satellite operators are compared. The telecom core network implementation of the service is detailed in the cases of a GSM type core network and an IS-41 (CDMA) core network.