Showing papers on "GSM frequency bands published in 2002"

Dual-mode RF communication device

Abstract: A novel RF to IF converter operates in two modes allowing both wide bandwidth signals and narrow bandwidth signals to be processed using the same wide bandwidth bandpass filter as well as a dual-mode image-reject mixer As a mobile receiver, both wide bandwidth WCDMA or IMT-2000 signals and narrow bandwidth GSM signals pass through the same wide bandwidth channel select filter In the GSM mode, signals lying to one side of the frequency range of the narrow GSM signal are attenuated by the wide bandwidth channel select filter Then signals lying to the other side of the GSM signal are attenuated by an image-reject mixer The image-reject mixer also downconverts the GSM signal In the WCDMA or IMT-2000 mode, the wide bandwidth channel select filter attenuates signals outside of the WCDMA or IMT-2000 channel bandwidth, and the image-reject mixer downconverts the wide bandwidth signal without rejecting signals

Comparison between radiation efficiencies of phone antennas and radiated power of mobile phones measured in anechoic chambers and reverberation chamber

Abstract: Chalmers University and Bluetest AB have developed a reverberation chamber that can be used to measure radiation efficiency of phone antennas and the radiated power of mobile phones. This paper describes the verification of the reverberation chamber measurements by comparison with two anechoic chambers. The total radiated power of each of ten different mobile phone models was measured. In addition, the antennas on eight of the phone models were fed by a cable (spare set of phones), and the radiation efficiencies were measured. Both the antenna radiation efficiency and the radiated power were measured in the presence of a head-and-shoulder phantom. The handsets were measured in only one position - the so-called left talk, 45/spl deg/ user-intended position. The phone tests were performed in the GSM 900 (GSM), GSM 1800 (DCS) and GSM 1900 (PCS) bands. There exists high correlation in the results of the radiation efficiencies and radiated power measured in the reverberation chamber and two different anechoic chambers, respectively. The agreement between the results of corresponding active and cable-fed devices is also good. Frequency stirring, platform stirring and polarization stirring are important for achieving accuracy when measuring in the reverberation chamber.

High directivity multi-band coupled-line coupler for RF power amplifier

Abstract: The present invention discloses a miniature high directivity multi-band coupled-line coupler for RF power amplifier module application. The coupler utilizes a three-coupled-line structure, with a first RF line designated coupled line for the GSM 900 MHZ band, a second RF line designated coupled line for the DCS/PCS 1800/1900 MHZ band, and a common coupled line. A first capacitor is connected between the center of the first line and the center of the common line and a second capacitor is connected between the center of the second line and the center of the common line. The coupler has a length considerably less than the length of a quarter wave length coupler while achieving directivity requirements for both GSM band and DCS/PCS band.

GSM 900/DCS 1800 fractional-N modulator with two-point-modulation

Abstract: This paper presents a fractional-N modulator architecture that uses the technique of two-point-modulation. This technique allows direct modulation of the VCO within the closed loop of a high resolution PLL based fractional-N frequency synthesizer, without restriction due to loop bandwidth and PLL dynamics. A prototype transmitter was implemented using the GSM standard to verify the superior performance predicted by simulation. The core element of this new modulator architecture is a PLL-based fractional-N frequency synthesizer. This prototype synthesizer consists essentially of a full custom IC for the analog section, and the digital functionality was implemented in a filed programmable gate array (FPGA). The analog circuitry was fabricated in a 25 GHz BiCMOS process with 0.8 /spl mu/m as minimum feature size. Measurements of the spectrum for the GSM modulated signal and of the demodulated signal show that the strict demands of the GSM specification can be met.

Method for dynamically mapping channels for new GSM frequency bands

Abstract: An apparatus and method for providing a dynamic mapping of channel numbers to physical frequencies for some cells of a cellular telephone system, for use in case of a cellular telephone system representing physical frequencies by channel numbers and providing a fixed mapping of channel numbers to physical frequencies. The method includes a step of providing an information element indicating the dynamic mapping, and is performed in a way that is compatible with an existing channel numbering space, thereby keeping unchanged any existing signaling messages. The method also provides for a change in a dynamic mapping: a duplicated mapping is broadcast in which two non-overlapping sets of channel numbers are both mapped at least in part to a same frequency block, the broadcasting being continued for a predetermined time assumed to be of sufficient extent that any mobile phones operating in the cells will have decoded the duplicated mapping.

CDMA/GSM double-mode mobile communication method and its communication equipment

Abstract: The present invention relating to a mobile communication method and its divice for being used in honeycomb frequency band aspect can be mainly used to establish radio communication with IS 95 GSM network or CDMA network. The method can be realized by designing CDMA or GSM mode auxiliary commonicatino module inferface and attaching a CDMA or GSM mode auxiliary communication module on mobile phone which can be used on GSM or CMDa system mode. The device can be built up with following steps, 1) to attach GSM mode auxiliary communication module expansion interface on mobile phone with CDMA mode so as to let mobile phone have expansible GSM mode, b) to attach CDMA mode auxiliary communication module expansion interface on mobile phone with GSM mode so as to let mobile phone have expansible CDMA mode, c) to attach GSM auxiliary communication module on mobile phone basically in CDMA mode to let it be double mode mobile phone which can select CDMA and GSM, d) to attach CDMA auxiliary communication module on mobile phone basically in GSM mode to let it be double mode mobile phone which can select GSM and CDMA. It this way, people can realy realize global communication with using the same one mobile phone.

A multiple–shape channel selection filter for multimode zero–IF receiver using capacitor over active device implementation

Abstract: In this paper, a base-band first stage filter for a 3G multimode zero-IF receiver is presented. The multiple-shape channel selection filter can be configured either in a W-CDMA or GSM/DCS mode, by a simple digital command. The structure is a third order Butterworth low-pass filter, implemented using the Gm-C technique. The equivalent input thermal noise is 26nV/√Hz for the GSM mode and 36nV/√Hz for the W-CDMA mode; the out-of-band IIP3 is 5.3dBvp and 4.7dBvp for the GSM and W-CDMA modes respectively. The in-band IIP1 is -1dBvp and -3dBvp for the GSM and W-CDMA modes respectively. The circuit consumes 1.9mA in the GSM mode and 450µA in the W-CDMA mode. The whole structure was implemented in a 0.25µm SiGe BiCMOS process with 2fF/µm2MIM capacitors permitting integration with a 3G multi-mode zero-IF receiver. This base-band circuit was layed out using capacitors over active devices implementation, in order to permit an important reduction of the die area.

PIFA‐monopole internal mobile phone antenna for GSM/DCS/PCS triple‐band operations

Abstract: A novel internal mobile phone antenna comprising a planar inverted-F antenna (PIFA) and a low-profile planar monopole, which are designed, respectively, for covering the DCS/PCS and GSM bands, is proposed in this paper. The PIFA and the planar monopole together occupy a compact volume of 6.8 × 7.0 × 34 mm3, and are suitable to be built-in within the housing of a mobile phone. In addition, both the PIFA and the planar monopole have simple structures, which makes the proposed antenna easy to design and implement with a relaxed fabrication tolerance. A prototype of the proposed antenna was constructed and experimentally studied. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 217–219, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10561

Hand-over testing method and testing apparatus

Abstract: PROBLEM TO BE SOLVED: To implement a hand-over test in a GSM (global system for mobile) communication system. SOLUTION: In the hand-over testing method for implementing the hand-over test between GSM base stations by sending a GSM test signal in which a frequency of each slot is changed to a mobile terminal which communicates with a GSM base station by using the GSM communication system, in response to a GSM frequency change request designating the frequency of a slot in the GSM test signal, within a frame to which the GSM frequency change request is inputted, set frequency data for obtaining the designated frequency and set attenuation quantity data for obtaining a predetermined output signal level are calculated. Afterwards, synchronously with the slots in a frame next to the frame to which the GSM frequency change request is inputted, the calculated set frequency data and set attenuation quantity data of the relevant slot are set to a carrier generating circuit and an attenuator in a test signal generating part. COPYRIGHT: (C)2004,JPO

Water pumping stations remote control system in depression areas based GSM-900 cellular communications system

Abstract: The article presents a remote control system for water pumping stations effected by means of a GSM cellular communications system. The paper shows the possibility of making use of a visualisation system in order to run research experiments. Characteristics of research at hand and issues to be solved are outlined.

Agile multi-band delta-sigma frequency synthesizer architecture

Abstract: The emerging cellular and wireless standards necessitate the development of multi-mode transceiver systems. The main challenge in such systems is to have a common frequency synthesizer architecture acting as the local oscillator. In this paper, we propose a multi-band delta-sigma modulator based synthesizer architecture. This novel synthesizer architecture has been successfully implemented in an RF-CMOS process. The synthesized frequencies include the GSM, PCS and DCS bands.

A multi-carrier base station receiver using a delta-sigma oversampling A/D converter

Abstract: This paper presents the results of work at TRW in developing a multi-carrier receiver for cellular base station applications. Replacing existing single carrier receivers with a multi-carrier receiver has the potential to significantly increase the capacity of existing mobile phone networks and reduce the cost per carrier. Implementation of a multi-carrier receiver has been limited by the large dynamic range requirements for GSM/EDGE and WCDMA standards, with the GSM 900 MHz band presenting the greatest challenge. TRW is leveraging several proprietary technologies that enable and facilitate this development, including the latest product in a series of high performance analog-to-digital converters (ADCs). The stressing requirements for very high dynamic range (up to 108 dB SNR), wide bandwidth, and high linearity are met by employing a delta-sigma ADC that redefines the state-of-the-art. TRW's world-class InP process is used to fabricate devices capable of the high level of oversampling needed to satisfy the demanding performance values. We describe the receiver architecture and present preliminary test results from our first engineering model, demonstrating the practicality of a multi-carrier receiver for cellular base stations.

Widened band antenna for mobile device

Abstract: PROBLEM TO BE SOLVED: To propose an antenna in which two waving slots are connected to a conductive patch. SOLUTION: This antenna for radio communication equipment provided with the conductive patch having the two waving slots, a ground, a short-circuit connection connecting the patch to the ground, and a feeder connection connected to the patch is disclosed. The antenna has a radiation diagram including a primary resonant band including frequencies 1950 MHz to 2100 MHz and having a width greater than 20%. The antenna can operate within a frequency domain covering UMTS, PCS, DCS and maybe, a GSM bands. An antenna of a similar type can be used on many types of devices that use different frequency bands, for instance, various frequency bands, etc., in each country. Radio communication equipment including the antenna is also disclosed.

High-frequency circuit device and mobile communiation apparatus

Abstract: A high-frequency circuit device is provided that is used in a multiband mobile phone or the like and reduces transmission losses in high-frequency switch circuits so that the output power of transmission amplifiers is decreased, thereby achieving a substantial reduction in power consumption. In a first high-frequency switch circuit (16) provided between a first transmission amplifier (11) in a GSM circuit and an antenna (24), a strip line having a length corresponding to 1/4 of a wavelength in a GSM frequency band of approximately 900 MHz is provided as a phase adjusting unit (25) in series connection with a transmission signal path.

Transmitting circuit and communication terminal unit

Abstract: When a signal of GSM 900 frequency band is transmitted, a bias voltage setting circuit sets an optimum bias voltage for the GSM 900 frequency band to a first stage amplifier and a second stage amplifier. The transmission signal is amplified by the two amplifiers. A signal that is output from the second stage amplifier is supplied to a low-pass filter. The low-pass filter attenuates unnecessary radiation waves from the transmission signal. A GSM 900 frequency band amplifier amplifies the output signal of the low-pass filter and outputs the amplified signal. When a signal of DCS 1800 frequency band is transmitted, the bias voltage setting circuit sets an optimum bias voltage fro the DCS 1800 frequency band to the first stage amplifier and the second stage amplifier. A DCS 1800 frequency band amplifier amplifies an output signal of the second stage amplifier, and outputs the amplified signal.

Practical Deployment of Frequency Hopping in GSM Networks for Capacity Enhancement

Abstract: GSM Frequency Hopping can realize increased capacity with marginal degradation in the Quality of Service. Measurements obtained from trial systems and operational networks have been presented to demonstrate that tight frequency reuse is viable. The behavior of the GSM RF parameters such as RXQUAL changes due to frequency hopping and the RF optimization of the cell parameters require careful attention. Synthesizer Frequency Hopping in a 1×1 frequency reuse pattern with 16% fractional load produces capacity gains in excess of 50%. It is also observed to be less sensitive to the variations in traffic load compared to the 1×3 fractional reuse. Fractional 1×3 reuse is more difficult to optimize in congested networks without traffic-directed congestion relief. Observations for cell parameter optimization are based on measured RF and network performance data from operational networks.

Signal processor implementation of decimation filters in flexible receivers

Abstract: Configurable or programmable hardware is used much more than some years ago in wireless receivers. In this area, the need to develop small sized mobile terminals operating flexibly in different systems is receiving increasing attention. In this paper, we describe a programmable solution for sampling rate adaptation in a flexible radio focusing on the GSM mode. We present the hardware needed for the overall architecture and the implementation aspects of the solution based on the signal processor families TMS320C62x and TMS320C55x.