GSM frequency bands

About: GSM frequency bands is a research topic. Over the lifetime, 559 publications have been published within this topic receiving 5067 citations.

A 5/sup th/ order /spl Sigma//spl Delta/ modulator for GSM/WCDMA dual-standard wireless receivers

Abstract: A MASH 2-1-1-1 structure with a 5 level internal quantizer at the last stage is designed for a very-low-IF GSM/zero-IF WCDMA receiver. According to the different signal bandwidth and dynamic range requirements, this sigma delta modulator is reconfigured to achieve the required resolution with less power consumption. In GSM mode, only the first stage (2nd order SigmaDelta ADC) is turned on to achieve 76dB DR with oversampling ratio of 64 and bandwidth of 400kHz; in WCDMA mode, all the stages are turned on, together with a 5 level quantizer at the last stage, to achieve 66dB dynamic range with oversampling ratio of 8 and bandwidth of 5MHz. For other standards, like Bluetooth, Zig-bee, ADSL etc., this multi-standard SigmaDelta modulator can be easily reconfigured as MASH 2-1 or 2-1-1 structures to achieve different requirements from different standards. The design was implemented in TSMC 0.35mum CMOS process with 3.3V power supply

Velocity Estimation of Mobile Terminals by Exploiting GSM Downlink Signalling

Abstract: In this paper, we experimentally evaluate algorithms for velocity estimation of a GSM 900 mobile terminal which are based on the analysis of the statistical properties of the fast fading process. It is shown how theses statistics can be obtained from the training sequences present in downlink transmission bursts without establishing an active connection. Realistic simulations of a GSM channel according to the COST 207 channel models have been conducted. These models incorporate effects like multipath propagation, fading, cochannel interference and additive noise. It is shown that velocity estimation by searching for the maximum slope of the power density spectrum of the fast fading performs best.

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.

Comparisons on thermal effects Of 1.8GHz electromagnetic field exposure on Swiss Albino mice

Abstract: Radio frequency (RF) and microwave (MW) radiation are electromagnetic radiation in the frequency ranges 3 kHz – 300 MHz, and 300 MHz – 300 GHz, respectively. While there have been many benefits from the use of RF frequency, people nowadays are concerned that a long-term exposure could affect their body biological system and health. The recent increase in the usage of mobile telephone has raised the public awareness on the effect of RF radiation. This research is conducted by setting up RF electromagnetic radiation experiment in such control environment to identify and study the devices that have potential to release any RF frequency that may effect on human health. The study for this research project concentrates on the radiation 1.8 GHz of RF on life sample since GSM1800 is commonly used around the world in mobile communication voice data calls. The GSM frequency bands or frequency ranges are the cellular frequencies designated by the International Telecommunication Union (ITU) for the operation of the GSM for mobile phones. Apart from that, a body temperature analysis between unexposed life sample and exposed life samples less than 1.8 GHz RF signals was conducted. The objective is to study the changes of body temperature effect on RF frequency exposure to Swiss Albino mice. A comparison is made between control cage mice which are free from any radiation and exposed cage mice. The main objective is to compare the effect in terms of their body temperature between male and female mice in control cage and exposed cage. The methodology was conducted by exposing mice to RF frequency within 2 months whereby the temperature was captured twice a day. This experiment also may assist to understand and study about the effects of RF radiation to life sample.

Antenna arrangement for a multimode mobile terminal

Abstract: A mobile multimode terminal is provided with multiple antennas between which frequency bands are divided. The claimed arrangement comprises three antennas 11-13, multimode phone transmitters/receivers 101-107 and at least one controllable switch 61-63 placed between the antennas and the transmitters/receivers and is operable in at least five mobile communication systems, i.e. GSM850 and/or US-TDMA850, GSM 900 and/or US-TDMA1900, GSM1800, GSM1900, WCDMA and/or CDMA2000. The first antenna 11 is adapted to transmit the signals of a first, second, third and fourth system (GSM850/US-TDMA850, GSM900/US-TDMA1900, GSM1800, GSM1900) and receive the signals of the first and third systems (GSM850/US-TDMA850, GSM1800), the second antenna 12 is adapted to transmit the signals of a fifth system (WCDMA/CDMA2000) and receive the signals of the second and fourth systems (GSM900/US-TDMA 1900, GSM 1900) and the third antenna 13 is adapted to receive the signals of the fifth system (WCDMA/CDMA2000). The antenna arrangement enables the terminal to operate worldwide in networks applying different frequency bands and technologies. The frequency bands of the antennas are arranged for each antenna in a way that the bands fill an optimal frequency area, thus accomplishing smaller total volume for the antennas and good performance.