Showing papers on "GSM frequency bands published in 2009"

Dual Band High Efficiency Class Ce Power Amplifier Based on CRLH Diplexer

Abstract: In this paper, the most adequate architecture to implement dual frequency ampliflers is shown. Composite Right/Left Hand (CRLH) and Extended Composite Right/Left Hand (ECRLH) transmission lines are studied and evaluated to flnd the most suitable structure for dual band power ampliflers. As an example, the performance of a class CE amplifler, working in TETRA and GSM frequency bands, is compared with simulations and measurement, showing good agreement.

A 0.13 $\mu$ m CMOS Quad-Band GSM/GPRS/EDGE RF Transceiver Using a Low-Noise Fractional-N Frequency Synthesizer and Direct-Conversion Architecture

Abstract: This paper presents a single-chip CMOS quad-band (850/900/1800/1900 MHz) RF transceiver for GSM/GPRS/EDGE applications which adopts a direct-conversion receiver, a direct-conversion transmitter and a fractional-N frequency synthesizer with a built-in DCXO. In the GSM mode, the transmitter delivers 4 dBm of output power with 1deg RMS phase error and the measured phase noise is -164.5 dBc/Hz at 20 MHz offset from a 914.8 MHz carrier. In the EDGE mode, the TX RMS EVM is 2.4% with a 0.5 dB gain step for the overall 36 dB dynamic range. The RX NF and IIP3 are 2.7 dB/-12 dBm for the low bands (850/900 MHz) and 3 dB/-11 dBm for the high bands (1800/1900 MHz). This transceiver is implemented in 0.13 mum CMOS technology and occupies 10.5 mm2. The device consumes 118 mA and 84 mA in TX and RX modes from 2.8 V, respectively and is housed in a 5 times 5 mm2 40-pin QFN package.

Method for measuring TD-SCDMA network by GSM/TD-SCDMA double-mode terminal with GSM mode

Abstract: The invention provides a method for a GSM/TD-SCDMA double-mode terminal working under a GSM mode to measure a TD-SCDMA network. The method comprises the steps as follows: A. under the idle state of GSM and under the service state of GSM, an idle frame and a latest time slot of a frame before the idle frame receive and store TD-SCDMA data; and B. the measurement on received signal strength instruction (RSSI) and received signal code power (RSCP) is carried out according to the stored TD-SCDMA data. The invention can measure the TD-SCDMA network, no matter GSM is under the service state or under the idle state, and therefore, when a TD-SCDMA network signal is stronger, the TD-SCDMA network is automatically switched to the TD-SCDMA mode.

Extremely compact dual-band PIFAs for MIMO application

Abstract: A MIMO structure consisting of two extremely compact planar inverted-F antennas (PIFAs) (lambda/60 x lambda/20 x lambda/6) is proposed for GSM 900 MHz and 2.4 GHz wireless local area network applic ...

An Analytical Approach to Enhance the Capacity of GSM Frequency Hopping Networks with Intelligent Underlay-Overlay

Abstract: Intelligent Underlay Overlay (IUO) scheme is one of the most cost effective solution for capacity enhancement of Global System for Mobile Communication (GSM) However, the overall gain from this type of complex architecture depends on how efficiently it is designed and available radio resources are utilized This paper proposes a step by step process to design IUO in order to optimize the gain Here, the network configurations are determined analytically and a traffic model is developed to estimate the traffic distribution among different layers of IUO cell Equations for frequency reuse in each layer are derived and Frequency Hopping (FH), Power Control (PC) and Discontinuous Transmission (DTX) are integrated Effect of various parameters on cluster sizes is studied It is found that for some cases it is better to utilize the advantages from FH rather than IUO when these features are combined Several factors are taken into consideration during design phase like co-channel cells, super area coverage, traffic distribution, ratio and speed of moving vehicles, blocking probability intended by operator etc Finally an IUO cell is designed which shows 4142% capacity enhancement over normal cells having similar features and resources

Evaluation of spectrum opportunities in the GSM band

Abstract: In this paper we explore the possibility of exploiting underutilized channels in the GSM bands. The secondary (unlicensed) users of the spectrum are the nodes of an overlay cognitive ad-hoc network, which opportunistically transmits in data channels left unused by the primary (licensed) system. The fundamental constraints for the secondary system are: 1) it uses the time slots/frequency channels (i.e. data channels) unused by the primary GSM system, 2) its operation does not degrade the performances of the primary system, 3) there is no exchange of signalling information between the primary and the secondary system to facilitate the secondary usage of spectrum, that is, the primary users are not cognitive aware. The focus is on the feasibility of the proposed approach, so that we consider a system level simulator based on a realistic GSM network deployed in the city of Bologna. In this context we evaluate the impact that the operation of the secondary users has on the performances of the primary system. In addition, we study the performances that can be obtained by the secondary system under the condition of marginal interference to the primary system. We will show that an appropriate choice of the frequency channel, makes the secondary usage of spectrum a valid approach to increase the operator's spectrum efficiency.

A novel wrist wear dual-band diversity antenna

Abstract: A novel wrist conformal dual-band antenna structure is proposed for application in watch-type wireless devices. Simulation results show that this structure can achieve good performance in dual GSM bands and high efficiency when worn on hand. Based on this structure, a dual-element diversity antenna is also proposed. More research regarding this novel structure will be done in the future.

SAR analysis in human head model exposed to mobile base-station antenna for GSM-900 band

Abstract: Friis transmission equation combined with Finite Difference in Time Domain (FDTD) method has been used to carry out investigation on Specific Absorption Rate (SAR) inside the human head model exposed to a 100 Watt GSM Base Station Antenna (BSA) at GSM-900 band. Maximum local SAR (MLSAR) has been calculated at 925 MHz, keeping distance between head and BSA in the range of 0.5 m to 5.0 m. The human head is modelled as an inhomogeneous sphere of diameter 21.0 cm. The objective of this study is to estimate MLSAR induced in the human head model by BSA and compared with recommended values.

Reduction of specific absorption rate in human tissues using split ring resonators

Abstract: In this paper, we are presenting a framework for investigation on mobile phone and human head interaction. As we all know that some of the radio waves emitted by a mobile phone handset are absorbed by the human head. The rate at which radiation is absorbed by the human body is measured by the Specific Absorption Rate (SAR). The SAR is calculated by using Finite Difference Time Domain (FDTD) Method. The results of the calculated peak or average SAR are correlated with the distance between the antenna and phantom and with the standing wave ratio at the antenna feed point. The results show that the energy absorbed by the biological tissue primarily depends on the operational parameters of the handset's antenna. To reduce the SAR, we use metamaterials to reduce the electromagnetic interaction between the mobile phone antenna and human head. It is found that the SAR in the head can be reduced by placing the metamaterials between the antenna and the head. By arranging split ring resonators (SRRs) periodically we get an electromagnetic shield. By properly designing structural parameters of SRRs, the effective permeability of the medium can be made negative around 900 and 1800 MHz GSM frequency bands. The design procedure will be described. Numerical results of the SAR values in a muscle cube and brain with the presence of SRR's exhibit significant SAR reduction. These results can provide helpful information in designing the mobile communication equipments for safety compliance.

Reduction of f1 neuronal excitability by exposure to 217hz magnetic fields from gsm 900 mobile phone

Abstract: Objective: The aim of this study was to investigate the effects of a 217 Hz magnetic field of mobile phone GSM 900 exposure on the bioelectric activity of F1 neuronal cells of the land

GSM/TD-SCDMA dual-mode terminal chip having single chip and single DSP construction

Abstract: The present invention discloses a GSM/TD-SCDMA terminal chip of a single-chip single DSP architecture, which realizes the GSM and TD system programs on a single DSP, thereby reducing the chip area and cost, lowering power consumption and improving the performance of interactive systems The chip includes: a micro-controller; a single clock generator and crystal vibration; and a single DSP chip The single DSP chip includes a chip control module, responding GSM frame interrupt and TD frame interrupt in time, distributing system resources to the GSM mode and TD-SCDMA mode, controlling the start-up of the GSM and TD-SCDMA radiofrequency signal, and shielding the GSM timer interruption or TD-SCDMA timer interruption for manually controlling network or single mode terminal; a sleeping mode dual affirmation module, detecting that the GSM and TD-SCDMA are all at a sleeping allowing state for allowing the DSP chip to enter into a sleeping mode; a GSM accelerator and a TD-SCDMA accelerator, for performing auxiliary digital signal processing to GSM and TD-SCDMA under the control of a single DSP The invention can be applied to the mobile communications field

Evaluation of a near field scanner for TRP and radiation pattern measurements of GSM mobile phones

Abstract: In this paper a new tool for estimation of the radio performance of terminal antennas in terms of Total Radiated Power, TRP is tested and evaluated. The tool is known as Lab Express and is developed by the Canadian company EMSCAN. The results from measurements performed with the Lab Express are compared with of the radiation patterns and total radiated power (TRP) estimates, measured with a CTIA approved Satimo SG24 chamber. The TRP and radiation pattern measurements are performed on 10 commercially available mobile phones at GSM 900 and GSM 1800 frequency bands. The dependency of the measured TRP on the positioning of the mobile phone on EMSCAN is also tested. Our results indicate that the TRP measured with Lab Express is well correlated with the results obtained from the Satimo SG24 chamber even though the Lab Express equipment seem to over estimate the TRP with on average about 4dB at 900MHz and about 1.3dB at 1800MHz.

A multi-band printed monopole antenna

Abstract: In this paper, we present an antenna design for multiband applications which can cover the GSM 900 (890–960 MHz), DCS (1710– 1880 MHz) and PCS (1850–1990 MHz), UMTS (1920– 2170 MHz), and WLAN2.4GHz (2400–2484MHz) frequency bands. A prototype is built and measured. Results of return loss, radiation patterns, and efficiency are given. The antenna is small, cheap to manufacture, has a low profile and would be suitable for wearable applications, mobile phones and base stations.

GSM frequency-hopping straightly-discharging station using baseband decoding mode

Abstract: The utility model relates to a GSM frequency hopping repeater using a baseband decoding mode, which is composed of a coupler, a diplexer, low-noise amplifiers, frequency selectors, power amplifiers and an antenna, wherein, an uplink low-noise amplifier, an uplink frequency selector and an uplink power amplifier are orderly connected to form an uplink; a downlink low-noise amplifier, a downlink frequency selector and a downlink power amplifier are orderly connected to form a downlink; the coupling end of the coupler is connected with the radio frequency input end of a frequency hopping controller, and the I/O interfaces of the frequency hopping controller are respectively connected with the I/O interface of the uplink frequency selector and the I/O interface of the downlink frequency selector. The utility model has the advantages of simple integral structure, scientific and reasonable design and high use reliability. In addition, the utility model can increase the quality of a wireless network, and can effectively reduce the interference of relay signals against a base station and the interference among frequency points. Thus, the utility model is a GSM frequency hopping repeater which uses a baseband decoding mode can accurately obtain the frequency hopping control.

Novel channelization multiplexer using Metamaterial filters

Abstract: This paper describes a novel channelization multiplexer for multi-band front-ends (B3G 450, GSM 900, GSM 1800 and W-CDMA 2100). This subsystem eliminates harmonic resonances by using Metamaterial (MTM) directional filters. The proposed configuration is simple to implement and is highly miniaturized.

A method for sharing rf receiving unit, apparatus and system thereof

Abstract: A method for sharing RF receiving unit is provided in the present invention, apparatus and system thereof. The method includes the following contents: setting the receiving frequency band of the RF receiving unit of the DBB FDD system and the GSM system to broad frequency receiving, and the frequency band of the broad frequency includes the receiving frequency band of the DBB FDD system and the GSM system; receiving the signals of the DBB FDD system and the GSM 900 system by using a bipolar broadband antenna at the same time in the BS, and the frequency band of the bipolar broadband antenna is the same frequency band as the broad frequency. According to the embodiments of the present invention, the additional transmitting/receiving loss couldn't be produced because no needing Diplexer; two systems could receive downlink signals together in one BS by only one bipolar broadband antenna (frequency band 790-960MHz) instead of two bipolar antennas.

Perencanaan ulang site jaringan gsm 900 dan 1800 di kota semarang

Abstract: Global System for Mobile Communication (GSM) is designed to provide solutions for high increasing number of subscribers of mobile communication services, while the frequency resources is limited. GSM is a digital cellular communication technology with a coverage service area is divided into small areas called cells, and each cell is handled by a site. To anticipate the growth of users number GSM system requires site re-planning that consist of three aspects, namely capacity, coverage and quality. With this site re-planning the number of site eficiency is expected. This paper has made simulation re-planning for an outdoor coverage site system of GSM radio network 900 and 1800 in Semarang city, which has area of 373.67 km2 and consists of 16 districts and 177 villages, so it can serve customers until 2014. From re-planning simulation for GSM 900 and 1800 radio network outdoor site coverage system in Semarang,can be known the needed number of sites to serve the customers until the year 2014 with a teledensity of 30%, i.e 91 sites with 250 Global System for Mobile Communication (GSM) sectoral cells and 230 Digital Cellular System (DCS) sectoral cells with the highest traffic for the micro cells occurred at sector 3, Sendangguwo village, District Tembalang that is equal to 132.36 Erlang, while the highest traffic for the macro cells occurred in Sector 3 Bamban Kerep village, District Ngaliyan which amounted to 66,24 E. Keywords: Re-planning, site, GSM, coverage, Semarang City

Method for implementing frequency selection of GSM frequency selector by using frequency hopping synchronization

Abstract: The invention relates to a method for implementing frequency selection of a GSM frequency selector by using frequency hopping synchronization, which comprises the following steps: firstly, radio-frequency signals are coupled to a frequency hopping synchronization control module, and frequency hopping synchronization information is obtained; secondly, the frequency hopping synchronization control module changes parameters of a frequency synthesizer according to the frequency point time series, the frequency synthesizer controls voltage controlled oscillators, and the voltage controlled oscillators output intrinsic signals; thirdly, the frequency hopping synchronization control module controls a switch at a time slot among GSM frames to switch between the two voltage controlled oscillators so as to output different intrinsic signals to be provided for intrinsic input ports of an upper mixer and a lower mixer so that the GSM frequency selector selectively receives the radio-frequency signals. The invention can improve the wireless network quality, effectively reduces the interference to a base station and the interference among the frequency points, improves the use reliability and has stronger practicability.

Bandwidth enhancement of a compact multiband film-antenna for mobile phones

Abstract: A film-antenna capable of generating two wide resonant modes for covering the AMPS/GSM bands and the DCS/PCS/ UMTS bands for mobile phones is proposed. The antenna consists of two superimposed radiating arms which can support two resonant modes by themselves. The frequency range of a resonant mode generated by one of the arm is arranged to differ a little with the corresponding mode of the other, at the fundamental and higher-order modes. As a result, the bandwidths at both of the resonant modes are significantly enhanced. The antenna has a dimension of 5×15×40 mm3 and shows fairly good omni-directional radiation patterns at all the operating bands.

External antenna for tdmb and gsm roaming

Abstract: An external antenna for a terminal is provided to improve convenience by performing switching between a TDMB(Terrestrial Digital Multimedia Broadcasting) antenna and a GSM(Global System for Mobil communication) roaming antenna. An external antenna for a terminal includes A TDMB antenna(10), a GSM roaming antenna(20), a connector(30), and a switching unit(40). The TDMB antenna is used for receiving the TDMB. The GSM roaming antenna is used for the global roaming at the GSM frequency band. The connector delivers the frequency signal received from the TDMB antenna or the GSM roaming antenna to the terminal. The switching unit switches to connect the connector connected to one of the TDMB antenna and the GSM roaming antenna to the other.

Method for lowering transmission interference of WCDMA frequency band to GSM frequency band

Abstract: The present invention discloses a method for reducing the transmission interference of WCDMA frequency band to GSM frequency band on WCDMA and GSM dual-mode mobile phone. The method executes optimized designing to the antenna switch of WCDMA, and adds a resistor for the unloaded branch line as a load. Simultaneously if drain voltage exists on the port of antenna switch, DC blocking capacitor requires to be added. The method of the invention can effectively reduce and avoid the effect of transmission interference of WCDMA frequency band to GSM frequency band. The method of the invention can realize high-performance WCDMA and GSM dual-mode mobile phone and satisfies the market demand.

A internal penta-band monopole with a parasitic strip for GSM850/GSM/900/DCS/PCS/UMTS operations

Abstract: A penta-band internal monopole antenna with a novel parasitic strip suitable for GSM850/GSM900/DCS/PCS/UMTS2100 applications is constructed and studied. The proposed antenna is located at the bottom of the edge of the ground plane in main printed circuit board (PCB). It has antenna matching network and one parasitic strip using the new conception of the parasitic mode and second mode. It is an internal penta-band antenna suitable for most Asia, American and European 2G/3G handheld devices. The simulated impedance bandwidth covers the required bandwidth of the GSM 850(824–894), GSM900 (880–960 MHz), DCS (1710–1880 MHz), PCS (1850–1990 MHz) and UMTS 2100 (1920–2170) bands.

Evaluation of a Near Field Scanner For Active Measurements of Mobile Phones

Abstract: The radio performance measurements of terminal antennas require expensive investments and they are often performed in anechoic chambers. Now a days measurement techniques using wheeler cap, reverberation chamber, etc have become popular. But these methods are used for measurements either during the design or production or in-network testing phases but not for all. Hence EMSCAN, a Canadian company, has come up with a device called Lab express near field scanner to counter this problem. In this thesis an attempt is made to study the EMSCAN near field scanner by looking into architecture and design aspects of this device. Moreover, the capability of the device to measure the radio performance of the terminal antennas in terms of radiation pattern and total radiated power (TRP) is also studied and anlaysed.The analysis of the TRP and radiation pattern measurements of the terminal antennas is done by comparing the EMSCAN measurement results of 10 commercially available mobile phones with that of CTIA approved Satimo SG24 chamber. The TRP and radiation pattern measurements are done for GSM 900 MHz and DCS 1800 MHZ low bands i.e.975 and 512 respectively. Furthermore, the dependency of the measured TRP on the positioning of the mobile phone on EMSCAN is tested by measuring the TRP and the radiated power of a single mobile phone. The measurement results after comparison suggest that there is a correlation of around 79% at 1800 MHz and 49% at GSM 900 MHz among the two methods. This leads to the conclusion that EMSCAN scanner cannot replace the anechoic chambers for estimating the radio performance of terminal antennas. The results obtained by measuring the mobile phone in 8 different positions suggest that there is no significant difference in the TRP measured. There is a difference of 1.25dB was observed between the maximum and minimum TRP measured in two different positions on the near field scanner. The results obtained by both the methods are verified by computing the TRP and radiation pattern in Matlab.The Matlab results agrees more with the EMSCAN results than Satimo SG 24 chamber results.