Showing papers on "GSM frequency bands published in 2014"

GSM whitespaces: An opportunity for rural cellular service

Abstract: The GSM network is the largest network on Earth, providing vital communications service to billions of people. Yet hundreds of millions of people live outside the coverage of existing cellular providers. Recently, researchers have demonstrated a new model of cellular connectivity, community cellular, that has the potential to bring coverage to extremely rural populations. Although the total capital costs for these networks (

Fire-Detectors Review and Design of an Automated, Quick Responsive Fire-Alarm System Based on SMS

Abstract: In this work a review of existing fire-detector types has been carried out along with the development of a low cost, portable, and reliable microcontroller based automated fire alarm system for remotely alerting any fire incidents in household or industrial premises. The aim of the system designed is to alert the distant property-owner efficiently and quickly by sending short message (SMS) via GSM network. A Linear integrated temperature sensor detects temperature beyond preset value whereas semiconductor type sensor detects presence of smoke or gas from fire hazards. The sensor units are connected via common data line to ATMega8L AVR microcontroller. A SIM300CZ GSM kit based network module, capable of operating in standard GSM bands, has been used to send alert messages. The system is implemented on printed circuit board (PCB) and tested under different experimental conditions to evaluate its performances.

Design and evaluation of multi-band RF energy harvesting circuits and antennas for WSNs

Abstract: Radio frequency (RF) energy harvesting is an emerging technology that will enable to drive the next generation of wireless sensor networks (WSNs) without the need of using batteries. In this paper, we present RF energy harvesting circuits specifically developed for GSM bands (900/1800) and a wearable dual-band antenna suitable for possible implementation within clothes for body worn applications. Besides, we address the development and experimental characterization of three different prototypes of a five-stage Dickson voltage multiplier (with match impedance circuit) responsible for harvesting the RF energy. Different printed circuit board (PCB) fabrication techniques to produce the prototypes result in different values of conversion efficiency. Therefore, we conclude that if the PCB fabrication is achieved by means of a rigorous control in the photo-positive method and chemical bath procedure applied to the PCB it allows for attaining better values for the conversion efficiency. All three prototypes (1, 2 and 3) can power supply the IRIS sensor node for RF received powers of -4 dBm, -6 dBm and -5 dBm, and conversion efficiencies of 20, 32 and 26%, respectively.

Efficient compact dual-band antennas for GSM and Wi-Fi energy harvesting

Abstract: Since the demand for autonomous wireless sensors increases, there is an important interest in battery-less systems that use radiofrequency (RF) energy harvesters. The key element on the receiving side of an energy harvesting system is the rectenna (rectifier + antenna) which receives electromagnetic power and converts it into electric continuous power. With the development of multiple frequency bands in today's wireless communication systems, the multi-band rectennas would be useful. Among various entities of rectenna, antenna is one of the important elements which is responsible for collecting the incoming RF signals of various frequencies. We present in this paper two efficient compact dual-band antennas for RF energy harvesters: a Printed-IFA for GSM bands with 1.3 dBi at 900 MHz band and 3.2 dBi at 1800 MHz band; and a quasi-Yagi for Wi-Fi bands with 5.7 dBi at 2.45 GHz band and 5.9 dBi at 5.3 GHz band. Also simulation and measurement results will be presented.

A 4×4 MIMO antenna system for mobile tablets

Abstract: This paper presents a 4×4 MIMO antenna system for mobile tablets. Each antenna of the MIMO system is capable of covering GSM 900(890-960MHz), GSM 1800(1710-1880 MHz), GSM 1900(1850-1990 MHz), UMTS (1920-2170 MHz), WLAN (2400-2480 MHz), WiMAX (3400-3600 MHz) and several LTE frequency bands. The MIMO antenna system is composed of four coupled fed monopole antennas which each antenna placed on the corner at the non-grounded portion of the circuit board. The substrate used for the circuit board is FR-4 substrate with relative permittivity of 4.4 and loss tangent of 0.02. The overall volume of the circuit board is 230 × 176 × 0.8 mm 3 with each antenna occupying an area of 75 × 11 mm 2 . To improve the isolation between antennas of the MIMO system a decoupling structure, consisting of ground slots and decoupling strips, was etched on the bottom layer of the circuit board. The isolation achieved is better than 15 dB over all the frequency bands covered by each antenna leading to an envelope correlation coefficient of less than 0.09. The simulation and measured results are in good agreement.

Development of a Semielliptical Partial Ground Plane Antenna for RFID and GSM-900

Abstract: A novel compact broadband patch antenna for UHF (ultrahigh frequency), RFID (radio frequency identification), and GSM-900 (global system for mobile communications) band is shown in this paper The antenna is composed of an ellipse shape annular ring at the patch The ground plane of the planar antenna is modified with a semiellipse shape slot The structure can generate substantial amount of current at the feed-line The geometry of the antenna is evaluated by using HFSS simulation software and deliberated across the paper Parametric study is exhibited to delineate the response change of the antenna The antenna has a physical width of 024 λ and length of 03 λ It covers a frequency starting from 09 GHz to 108 GHz A fractional bandwidth of 182% has been achieved from 09 GHz till 108 GHz An average gain of 55 dBi is achieved at the resonance frequency The simulated and measured results have good agreement

Wide band FSS for increased thermal and communication efficiency in smart buildings

Abstract: A tri-layer wide band FSS has been presented for hard-coated energy saving glass used in modern building architecture. Due to the presence of coating which blocks infrared signals and passes visible spectrum, there is an attenuation in the useful microwave signals as well, which is a drawback. Designing a band-pass FSS in the coating can be a solution to the problem. The proposed design is consisted of three FSS layers with a high-pass FSS sandwiched between two low-pass FSSs separated by glass layers. On average, it provides an improved transmission magnitude in -10 dB bandwidth of 1.4 GHz (0.62 - 2.02 GHz) which covers GSM 900/1800/1900 MHz, GPS, UHF TV, security bands etc. Due to complimentary FSSs structures, the infrared loss due to etching has been minimized and its efficiency is improved. It also provides 2.45 GHz WLAN security by confining signals to the interior of the building. The FSS design has a stable frequency response for both TE and TM polarizations up to 45°. It's performance is significantly enhanced in terms of average transmission magnitude improvement in -10 dB bandwidth, oblique incidence stability and loss/efficiency of infrared signal compared to the recently published research.

RF energy harvesting and remote powering at 900MHz and 2.4GHz

Abstract: This work presents the development of two low cost RF energy harvesters dedicated to the ISM bands. The rectifiers exhibit respectively a maximum of power efficiency of 47% and 33% at 900MHz and 2.4GHz. Focusing on the sensitivity, the harvesters provide a IV output voltage at 3m with a radiated power of 27dBm at 2.4GHz, and 11m with a radiated power of 30dBm at 900MHz. The demonstration of energy scavenging is further proposed by the remote powering of a clock (0.9V/5uA) during the download of a video with a cellphone in GSM mode, and then the data broadcasting in bluetooth mode by a tablet.

An empirical 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 standardized IEEE 80222 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 signaling Existing mobile communication system uses CDMA 800, GSM 900, GSM 1800 and WCDMA 2000 MHz bands for which approximately l/8th of the band capacity is used for in-band signaling 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 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 analyzed using RF analysis software and spread sheet database An analysis of the collected data lead to arrive at the conclusion that more than l/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 Also, with the help of collected data of eight cities, an empirical relationship has been established which can be taken as a thumb rule for projection of channel occupancy from densely populated core areas of big cities to less populated township areas when population is known

Experimental Characterization of Wearable Antennas and Circuits for RF Energy Harvesting in WBANs

Abstract: Field trials have been performed in Covilha to identify the spectrum opportunities for radio frequency (RF) energy harvesting through power density measurements from 350 MHz to 3 GHz. Based on the identification of the most promising opportunities, a dual-band printed antenna was conceived, operating at GSM bands (900/1800), with gains of 1.8 and 2.06 dBi, and efficiency varying from 77.6 to 82%, for the highest and lowest operating frequency bands, respectively. In this paper, guidelines for the design of RF energy harvesting circuits and choice of textile materials for a wearable antenna are briefly discussed. Besides, we address the development and experimental characterization of three different prototypes of a five-stage Dickson voltage multiplier (with and without impedance matching circuit) responsible for RF energy harvesting. All the three prototypes (1, 2 and 3) can power supply the sensor node for RF received powers of 2 dBm, -3 dBm and -4 dBm, and conversion efficiencies of 6, 18 and 20%, respectively.

Study on ESD Effects of GaAs HBT Power Amplifiers for DCS/GSM Dual Band Handsets

Abstract: Study on electrostatic discharge (ESD) impact on the GaAs HBT power amplifier (PA) in DCS/GSM dual band handsets is performed in this paper, which has been regarded as its main reliability issue accounting for most failures of radio frequency integrated circuits. In order to suppress the positive ESD impact on the PA in an effective but very economic way, a set of forward ESD diodes at its input port is replaced by the PN junction of GaAs HBT transistor in its first-stage. Alternatively, to introduce a set of thin film resistors (TFRs) at the front of a HBT transistor is necessary for improving the S 11 -parameter and stability of PA; however, their electrothermal breakdown possibilities do exist. Therefore, both performance degradation and breakdown events of several PA dies are measured for different ESD voltages described by the human body model, with different TFRs chosen for both DCS and GSM bands, respectively. Their transient temperature responses are also captured and compared for different ESD waveforms, which are predicted using the in-house developed algorithm based on the hybrid time-domain finite-element method.

A reconfigurable low-pass/high-pass $$\varDelta \varSigma$$ΔΣ ADC suited for a zero-IF/low-IF receiver

Abstract: This paper presents the design of a reconfigurable delta sigma analog to digital converter. Its main degree of freedom is the choice of the noise shaping between low-pass and high-pass. Thanks to this reconfiguration parameter, the converter takes full advantage of both noise shapings and employs the most suited architecture depending on the received standard. Moreover, the low-pass/high-pass reconfiguration makes the analog-to-digital converter compliant for both the low-IF and the zero-IF receiver architectures. The paper also presents a novel reconfigurable dynamic element matching technique which efficiently addresses the digital to analog converter mismatch for both the high-pass and the low-pass delta sigma modulators. The sampling frequency and the quantizer number of bits are likewise adjustable. A GSM/UMTS compliant delta sigma analog to digital converter including reconfigurable decimator has been designed in a 1.2 V 65 nm CMOS process. The high-pass modulator is employed in a low-IF receiver for the GSM mode to profit from its robustness against offset and 1/f noise. For the UMTS mode, the low-pass modulator is employed in a zero-IF receiver because of its lower sensitivity to clock jitter.

Hazard estimation from Radiofrequency Radiation in a Nigerian Teaching Hospital from nearby GSM Base-Stations

Abstract: Increasing competition between GSM service providers and several calls for improvement of their quality of service from members of the public has led to proliferation of base station (BTS) masts in Nigeria. Consequently, there is an increase in the risk of radiation hazard due to exposure of the public to radiofrequency radiation from the BTS antennae. This study is aimed at estimating the radiation hazard due to electric field intensity from BTSs.Electric field intensity measurements due to different GSM Operators were taken at thirty sites in the 900MHz and 1800MHz frequency bands. The maximum instantaneous electricfield intensities of 301.05 ± 63.85mV/m and 241.49 ± 57.00mV/m were obtained for GSM900 and GSM1800 respectively. Estimation of the specific energy absorption rate (SAR) yield 39.00μW/kg and 34.80μW/kg for the skin, while that of the brain yield 33.90μW/kg and 32.70μW/kg for GSM 900 and GSM 1800 respectively. The skin penetration depth for the worst case of exposure was obtained as 4.16cm. Exposures in the study area are below the ICNIRP reference level.

Method and terminal for gsm cell searches

Abstract: It is presented a method for Global System for Mobile communications, GSM, cell searches. The method is performed in a wireless terminal (1) of a cellular network when the wireless terminal is active in a non-GSM radio access technology and comprising the steps of: scheduling (40) reception of a part of a frame burst of a GSM frequency in said cellular network for said wireless terminal (1); searching (41) digital samples received on said GSM frequency for a predefined logical channel pattern. A corresponding wireless terminal, computer program and computer program product are also presented.

Interfrequency and inter-technology neighbor planning on a self-organizing network

Abstract: In an example, a self-organizing network (SON) provides automated interfrequency load balancing for a base station such as a NodeB. The NodeB may provide a plurality of carriers, such as in a plurality of UARFCN frequencies, and the SON may provide configuration directives for increasing efficiency. For example, when one carrier becomes loaded, the SON may update neighbor associations to take advantage of relatively unloaded frequency carriers. A plurality of scenarios S may be provided, and a policy P may be defined for each. When the NodeB encounters a scenario S, SON may send configuration directives to implement policy P. Similar concept and policy could be applied in conjunction with INTER Technology Neighbor Definitions between LTE and UMTS and UMTS and GSM. Example if GSM Frequency Neighbors needs to be replaced with different Frequency Neighbors from UMTS based on Load or RF conditions.

Mobile phone platform vehicle-mounted control system based on GPS and GSM technologies

Abstract: The utility model belongs to the technical field of automobile electronics and specifically relates to a mobile phone platform vehicle-mounted control system based on GPS and GSM technologies. The system comprises an original vehicle starting control circuit, a main control unit and a mobile phone intelligent control interface platform. The main control unit is provided with a GPS+GSM module, an MCU1 and an MCU2; the GPS+GSM module is connected with the MCU1 in a circuit; and a signal channel is formed by the mobile phone intelligent control interface platform, the GPS+GSM module, the MCU1 and the original vehicle starting control circuit. According to the utility model, the intelligent control of a vehicle by intelligent mobile phone operation is realized, more vehicle control functions are integrated in the system, the real-time performance is good, convenient and fast operation is enabled, and the realized functions comprise a GPS positioning function, GSM network communication, intelligent conversation operation, and a combination of control modes. Besides, in the technical field of a mobile phone controlled vehicle, the problems of slow channel transmission, long time delay, poor real-time performance, non-integrated more vehicle control functions and the like when mobile phone short messages are utilized to control a vehicle to perform simple operation mainly in a GSM mode in the prior art can be solved.

Pervasive RF energy harvesting system (GSM 900 and GSM 1800)

Abstract: RF energy harvesting holds a promising future for generating a small amount of energy to potentially power on low power devices like wireless sensor network. Due to path loss and restriction on transmit power; the RF power available to the input of the RF energy harvesting system is relative low. In this work, we show how wireless power transfer can occur more efficiently by the design of a high Q coil antenna. The receiving antenna and RF-DC converter are being analyzed and discussed. Finally, a prototype is fabricated and it shows capability to harvest a voltage in the range of 2V stored in the super capacitor from the air without a prominent source nearby. So, is RF energy harvesting ever going to become a practical reality? The answer is a cautious yes.

Detection method of GSM (Global System for Mobile Communications) frequency calibration package

Abstract: The invention relates to the synchronization technology in the technical field of mobile communication, and provides a detection method of a GSM (Global System for Mobile Communications) frequency calibration package. The detection method of the GSM frequency calibration package comprises the following steps: step 1, sampling GSM baseband signals to obtain a sampled data sequence of the GSM baseband signal, wherein the sampling frequency is the data rate of GSM; step 2, calculating phase difference of signals of two adjacent sampling points in the sampled data sequence of the GSM baseband signal; step 3, if the phase differences of continuous N adjacent sampling points in the sampled data sequence are more than 0, determining that the frequency calibration package is detected, wherein N is a positive integer, not less than 140 and not more than 148. The invention further provides a detection device of the GSM frequency calibration package. According to the method and device provided by the invention, the calculation amount, complexity and cost of the system can be reduced.

A compact multi-band planar inverted-F antenna with reduced SAR for mobile terminals

Abstract: This paper proposes a novel low SAR multi-band PIFA structure with reduce exposure of the human head to mobile-set antenna radiation. Triple band PDA structure operating at GSM 900, GSM 1900 and Wi-Fi bands are designed and fabricated. Analysis of SAR is SAR is decreased by reducing the radiation towards human head, while maintain significant radiation in all other directions. This SAR reduction is accomplished by inserting suitable slots in the top radiating patch and ground plane of PDA at appropriate positions so as to modify the current distribution and radiation pattern.

A reconfigurable low-pass/high-pass DR ADC suited for a zero-IF/ low-IF receiver

Abstract: This paper presents the design of a reconfigu- rable delta sigma analog to digital converter. Its main degree of freedom is the choice of the noise shaping between low-pass and high-pass. Thanks to this reconfig- uration parameter, the converter takes full advantage of both noise shapings and employs the most suited archi- tecture depending on the received standard. Moreover, the low-pass/high-pass reconfiguration makes the analog-to- digital converter compliant for both the low-IF and the zero-IF receiver architectures. The paper also presents a novel reconfigurable dynamic element matching technique which efficiently addresses the digital to analog converter mismatch for both the high-pass and the low-pass delta sigma modulators. The sampling frequency and the quan- tizer number of bits are likewise adjustable. A GSM/UMTS compliant delta sigma analog to digital converter including reconfigurable decimator has been designed in a 1.2 V 65 nm CMOS process. The high-pass modulator is employed in a low-IF receiver for the GSM mode to profit from its robustness against offset and 1/f noise. For the UMTS mode, the low-pass modulator is employed in a zero-IF receiver because of its lower sensitivity to clock jitter.

Cell Phone Detection and Jamming System for GSM - 900 MHz and 1800 MHz Frequency Bands

Abstract: This paper deals with the design & implementation of a low cost Cell Phone Detection System with a "Denial of Service" technique jamming. The cell phone detector is a RF based sensor which monitors the RF activity in the vicinity. The Jammer generates a RF signal on the same frequency as that used by the Communication carriers with modulated noise with a greater power than that of that of the original signal. This causes collision between the two RF signals, which cancels the incoming or outgoing signal from the cell phone with respect to the Base station.

Bandwidth Enhancement for Planar Inverted F Antenna

Abstract: Planar Inverted F Antenna (PIFA) is popular and widely used in handheld wireless devices because of several significant advantages. However, PIFA also has many shortages that become big limitations for its commercial application, such as narrow bandwidth. Therefore, it is a great challenge to design a PIFA with good performance. In this paper, a conventional PIFA working on GSM dual-band system (GSM 900: 900 MHz and GSM 1800: 1800 MHz) was investigated first. Then, by adding a stub on the feed line, the narrow bandwidth problem of this PIFA was well solved. By this method, no additional cost is needed, and also it is easy to manufacture.

Low cost Multi-band planar antenna for mobile phone applications

Abstract: In this paper a novel Multi-band planar antenna structure is presented for GSM 900, DCS 1800, 3G (UMTS 2000) and 4G (LTE Advanced) applications. The antenna is optimized and simulated by using CST Microwave studio, 3-dimentional full wave electromagnetic simulation software. This antenna structure has a partial ground that was optimized into simulation. After the achievement, we have tested and validated this multi-band antenna by using R&S VNA.

Wireless Mobile Charging Using Rectenna

Abstract: The purpose of this work is to build a system for mobile to wirelessly charge it using microwaves. The main component used for conversion of message signals, in the form of microwaves, to electrical signals is rectenna. The rectenna is a microstrip antenna, which operates at GSM frequency (1.8GHz) having low S11 parameter, followed by a rectifier circuit having a bridge topology, consisting of schottky diodes. The designed antenna shows bandwidth of 50MHz, having return loss -21dB and efficiency 45%. There are some additions in mobile phone to apply this technique as a sensor and a filter. With this technique the need for separate chargers for mobile phones is eliminated and makes charging universal. Thus the more you talk, the more is your mobile phone gets charged.

Composite glonass/ gps+gsm-900/1800 system

Abstract: FIELD: radio engineering, communicationSUBSTANCE: composite GLONASS/GPS+GSM - 900/1800 system, having a GLONASS/GPS system antenna with an amplifier, a passive antenna designed to receive and transmit data in GSM networks and two feeders, characterised by that it further includes a metal base covered by a radiotransparent cap; wherein said passive antenna is vertically mounted on the base, said passive antenna being a dielectric plate, on the top edge of one the surfaces of which are deposited two current-conducting rectangles which are oriented with their long sides parallel to the metal base, on the lower edge of the two current-conducting rectangles, oriented with their short sides parallel to the metal base, between the two rectangles, situated on the lower edge, there is a third current-conducting rectangle with a rounded vertex An inverted L shaped element is attached to the vertex, wherein the GLONASS/GPS system antenna with the amplifier is mounted on the metal base in a plane perpendicular to the dielectric plate and symmetrical to its end partEFFECT: increasing the power of signals in the GSM-900/1800 range and reducing the shielding effect of the structure of a GSM antenna on a GLONASS antenna2 cl, 1 dwg

Design of 4G Antenna for Mobile Handset

Abstract: A compact multiband planar antenna is designed for mobile phone applications in this paper. A planar monopole antenna into distributed radiating elements has designed to obtain good antenna performance. The proposed antenna is combined of a chopped circular radiator with a meander line and an L-strip coupled element which is an extension of the ground plane. A chopped circular patch and L-shaped coupling strip generates lower band and separate radiator and meander lines generates upper band. A planar structure has dimensions as 17.6 × 56 mm. Such a planar structure has printed on circuit board. Antenna covers wireless communication bands as LTE 750, GSM 850, GSM 900, DCS 1700, UMTS-2110, and UWB 3100. The designed antenna performance has checked with the help of IE3D simulation software. The proposed antenna has designed and tested practically. General Terms Microstrip patch antenna, Mobile communication, Multiband antenna.