GSM Signal Research Articles

Ad hoc Network for Emergency Rescue System based on Unmanned Aerial Vehicles

Intelligent Unmanned Aerial Vehicles (UAVs) on emergency rescue is widely used to detect injured mountaineers in inaccessible areas. These systems should satisfied several features. On the one hand, it is important to know the georeference of the injured mountaineers. It is also important to have real-time images of the situation and the area where people have been hilly. For this reasons, in this paper, we present the development of a UAV integrated within a wireless ad hoc network and a communication protocol able to transfer between several UAV’s and Smartphones working with Android OS. This paper also shows how to extend the concept of ad hoc network on Smartphones to extend wireless coverage for emergency situations in critical areas without GSM cellular coverage. After developing our system, we have focused our effort on demonstrating the correct operation of our UAV and its network performance when the system is used to track within a zone. Experimental results show the big potential of this kind of networks working on hostile terrain such as big mountains, ravines and river canyons without GSM signal communication.

Indoor Localisation Based on GSM Signals: Multistorey Building Study

Among the accurate indoor localisation systems that are using WiFi, Bluetooth, or infrared technologies, the ones that are based on the GSM rely on a stable external infrastructure that can be used even in an emergency. This paper presents an accurate GSM indoor localisation system that achieves a median error of 4.39 metres in horizontal coordinates and up to 64 percent accuracy in floor prediction (for 84 percent of cases the floor prediction is mistaken by not more than a single floor). The test and reference measurements were made inside a six-floor academic building, with an irregular shape, whose dimensions are around 50 metres by 70 metres. The localisation algorithm uses GSM signal readings from the 7 strongest cells available in the GSM standard (or fewer, if fewer than 7 are available). We estimate the location by a three-step method. Firstly, we propose a point localisation solution (i.e., localisation based on only one measurement). Then, by applying the central tendency filters and the Multilayer Perceptron, we build a localisation system that uses a sequence of estimations of current and past locations. We also discuss major accuracy factors such as the number of observed signals or the types of spaces in the building.

Secure Electromagnetic Buildings Using Slow Phase-Switching Frequency-Selective Surfaces

The concept of a secure electromagnetic building (SEB) which can successfully prohibit wireless communications is presented. Wireless security is achieved using a slow phase-switching technique and can be realized by time-varying the transmission properties of a frequency-selective surface (FSS) to increase the bit error rate (BER) of the unwanted signal. Results are presented which demonstrate that a technique of phase switching at rates much lower than the baseband data rate can be used successfully. The system has been implemented using a reconfigurable dual-polarized dual layer FSS incorporating varactor diodes where over 100° of phase change can be achieved for voltage changes of $\pm 0 - 3V$ . A vector signal analyzer was used to evaluate the BER performance of the system for a GSM signal operating at 2 GHz. BERs are shown to be as high as 36% which are sufficient to successfully prohibit wireless communication. The solution is also shown to be robust over a wide range of incidence angles, which is important for real-world applications where the location of the prohibited wireless source may be unknown or mobile. Furthermore, as the system is reconfigurable, the building can be switched between secure and nonsecure modes.

Using of GSM and Wi-Fi Signals for Indoor Positioning Based on Fingerprinting Algorithms

In the paper framework for indoor positioning utilizing Wi-Fi and GSM signals is introduced. Nowadays, indoor positioning is a very attractive topic for researchers, since accurate and reliable positioning system can unlock new market to service providers. In this paper we will analyse the use of Wi-Fi and GSM signals and their combination for the fingerprinting based positioning in the indoor environment. Performance of positioning system in terms of accuracy was analysed using simulations. In the simulations the position of the mobile device was estimated in three ways, when only GSM signals were used, when only Wi-Fi signals were utilized and when a combination of both signals was used. Three positioning algorithms from the Nearest Neighbour (NN) family were used in the simulations. Simulations were performed in the simulation model created in MATLAB environment.

Application of Genetic Algorithm for the Optimization of Energy Saving Glass Coating Structure Design

Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient.

Real-time assessment of possible electromagnetic-field-induced changes in protein conformation and thermal stability.

Previous studies on possible interactions of radiofrequency electromagnetic fields (RF EMFs) with proteins have suggested that RF EMFs might affect protein structure and folding kinetics. In this study, the isolated thermosensor protein GrpE of the Hsp70 chaperone system of Escherichia coli was exposed to EMFs of various frequencies and field strengths under strictly controlled conditions. Circular dichroism spectroscopy was used to monitor possible structural changes. Simultaneously, temperature was recorded at each point of observation. The coiled-coil part of GrpE has been reported to undergo a well-defined and fully reversible folding/unfolding transition, thus facilitating the differentiation between thermal and non-thermal effects of RF EMFs. Any direct effect of EMF on the conformation and/or stability would result in a shift of the conformational equilibrium of the protein at a given temperature. Possible immediate (t ≤ 0.1 s) and delayed (t ≥ 30 s) effects of RF EMFs were investigated with sinusoidal signals of 0.1, 1.0, and 1.9 GHz at various field strengths up to 5.0 kV/m and with GSM signals at 0.3 kV/m in the protein solution. Taking the overall uncertainty of the experimental system into account, possible RF EMF-induced shifts in the conformational equilibrium of less than 1% of its total range might have been detected. The results obtained with the different experimental protocols indicate, however, that the conformational equilibrium of GrpE is insensitive to electromagnetic fields in the tested range of frequency and field strength.

Application of Genetic Algorithm to the Design Optimization of Complex Energy Saving Glass Coating Structure

Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient.

Effects of Climatic Change On Gsm Signal in Lagos Metropolitan Terrain

The nexus of this study is to examine thoroughly the dependence of climatological parameters on GSM signal, especially in a metropolitan terrain. To validate this work, field measurements were carried out in the ITU regions of Lagos metropolitan area. The measurement system consisted of live documented radio base stations (BS) data transmitting at 13GHz, 15GHz and 23GHz in seven sites that constituted a metropolitan environment. The seven sites were segmented into non-urban (rural), suburban, urban, Ex-urban, dense-urban, micro-urban and peri-urban propagation environment. The Rain outage of the annual unavailability of the region of metropolitan data was collected using a Lenovo Laptop with installed path loss software alongside a licensed key called DONGLE. Results of this effort reveal that climate change affects signal propagation.

Determination of Pathloss Exponent Using Gsm Signal in Orhuwhorun Environ, Delta State

Determination of Pathloss Exponent Using Gsm Signal in Orhuwhorun Environ, Delta State

Determination of Building Penetration Loss of Gsm Signals, Using Selected Buildings in Orhuwhorun, Delta State, Nigeria as a Case Study

Determination of Building Penetration Loss of Gsm Signals, Using Selected Buildings in Orhuwhorun, Delta State, Nigeria as a Case Study

Determination of GSM Signal Strength Level in Some Selected Location in EKPOMA

In this work, the empirical method was adopted because it involves the measurement of large data, with the help of software called RF signal tracker which was installed in a mobile phone called Samsung galaxy pocket, this software gave us the distance to site (base station) and the signal strength level of the network provider at a particular distance. From my data, it was observed that the calculation of path loss with log – distance model which is deterministic is not as accurate as the empirical model (generated model), the generated model gave a better and more accurate result than the existing ones, and that the path loss exponents of the tested locations was fully known. Model was developed to calculate the power received of GSM signal in Ekpoma and the model was named “Generated model”.

An Analysis of High Precision Detection Technique for Wireless Positioning System

In order to solve the issue of high precision detection for mobile phone, an effective approach for triggering the GSM signal is proposed to make the phone transmit the frequency hopping signal which can be established without user interaction. An algorithm of time delay estimation for frequency hopping is proposed and verified by the simulation. The results show that bandwidth signal of frequency hopping can be used which leads to the estimation errors range of approximately [-4.3m, +4.3 and the multipath resolution is improved as well. The technique is therefore ideally suited for high precision of mobile station location.

Reconfigurable frequency selective surface for use in secure electromagnetic buildings

Practical measurements of a reconfigurable frequency selective surface (FSS) designed to stop the transmission of the GSM network protocol are shown. The method uses the time-varying transmission phase of the FSS to impair a GSM signal transmitted into a building or room, such that the receiver cannot detect the incoming signal. Measurements of the FSS response are shown for varying reconfigurable states and the FSS has been tested against a GSM signal to observe the level of impairment offered by the FSS. It is shown that the FSS can provide up to 35% bit error rate.

Improving GSM Services in Nigeria Through Interference Mitigation

Since the early days of wireless communication till today, there has been the simple dipole (oneelement) antenna which functions by radiating and receiving radio frequency (RF) energy equally well in all directions. This rather unfocussed/indiscriminate approach of radiating RF signals is just adequate for simple RF environments where no specific knowledge of the whereabouts of the gsm user is available. It is very clear that as huge amounts of RF power is radiated into the environment, only a small portion of it is received. Given this limitation therefore, this present and obsolete technique attempts at overcoming its challenges by simply boosting the power levels of the signal which it pushes blindly into the atmosphere. Unfortunately, all the gsm operators in Nigeria and indeed in many countries, have continued to deploy obsolete antenna systems (Omnidirectional and Sector antennas) which are characterized by colossal waste in RF energy and interference. This paper presents the result of an investigation and combination of two techniques of Direction of Arrival (DOA) Estimation and Beam Pattern Synthesis (BPS) for suitable implementation in antenna system, the combination of which will ensure that (a) RF energy is not available in areas where gsm users are non-existent (b) RF energy is available in only the areas where there is at least one gsm user with wireless device turned on. The DOA estimation technique proposed in this paper is the Multiple Signal Classification (MUSIC). For the BPS, the Least Mean Square (LMS) technique is used. Validation of the workings of these two applications, which form the Digital Signal Processing (DSP) algorithm for the antenna system, was carried out using the Matlab as the simulation tool. In the case of the MUSIC technique, the simulation was run for four different signals originating from different directions (or angles) using a fixed number of antenna elements. The results show clearly the ability of the system to identify each gsm signal and its direction of arrival. In the case of LMS technique, simulation was run for two signals, one desired and the other undesired (interferer). The results for the pair of signals are displayed graphically, where the unwanted signal is seen mitigated by the system. The combination of DOA and BPS for implementation in gsm networks ensures that the huge waste in RF energy and interference will be a thing of the past as the energy will be available only in the area needed. DOI: 10.5901/jesr.2013.v3n4p121

Long-term effects of 900 MHz radiofrequency radiation emitted from mobile phone on testicular tissue and epididymal semen quality

The purpose of this study is to bridge this gap by investigating effects of long term 900 MHz mobile phone exposure on reproductive organs of male rats. The study was carried out on 14 adult Wistar Albino rats by dividing them randomly into two groups (n: 7) as sham group and exposure group. Rats were exposed to 900 MHz radiofrequency (RF) radiation emitted from a GSM signal generator. Point, 1 g and 10 g specific absorption rate (SAR) levels of testis and prostate were found as 0.0623 W/kg, 0.0445 W/kg and 0.0373 W/kg, respectively. The rats in the exposure group were subject to RF radiation 3 h per day (7 d a week) for one year. For the sham group, the same procedure was applied, except the generator was turned off. At the end of the study, epididymal sperm concentration, progressive sperm motility, abnormal sperm rate, all-genital organs weights and testis histopathology were evaluated. Any differences were not observed in sperm motility and concentration (p > 0.05). However, the morphologically normal spermatozoa rates were found higher in the exposure group (p < 0.05). Although histological examination showed similarity in the seminiferous tubules diameters in both groups, tunica albuginea thickness and the Johnsen testicular biopsy score were found lower in the exposure group (p < 0.05, p < 0.0001). In conclusion, we claim that long-term exposure of 900 MHz RF radiation alter some reproductive parameters. However, more supporting evidence and research is definitely needed on this topic.

Influence of GSM Signals on Human Peripheral Lymphocytes: Study of Genotoxicity

Exposure to radiofrequency (RF) electromagnetic fields (EMF) is continuously increasing worldwide. Yet, conflicting results of a possible genotoxic effect of RF EMF continue to be discussed. In the present study, a possible genotoxic effect of RF EMF (GSM, 1,800 MHz) in human lymphocytes was investigated by a collaboration of six independent institutes (institutes a, b, c, d, e, h). Peripheral blood of 20 healthy, nonsmoking volunteers of two age groups (10 volunteers 16-20 years old and 10 volunteers 50-65 years old) was taken, stimulated and intermittently exposed to three specific absorption rates (SARs) of RF EMF (0.2 W/kg, 2 W/kg, 10 W/kg) and sham for 28 h (institute a). The exposures were performed in a setup with strictly controlled conditions of temperature and dose, and randomly and automatically determined waveguide SARs, which were designed and periodically maintained by ITIS (institute h). Four genotoxicity tests with different end points were conducted (institute a): chromosome aberration test (five types of structural aberrations), micronucleus test, sister chromatid exchange test and the alkaline comet assay (Olive tail moment and % DNA). To demonstrate the validity of the study, positive controls were implemented. The genotoxicity end points were evaluated independently by three laboratories blind to SAR information (institute c = laboratory 1; institute d = laboratory 2; institute e = laboratory 3). Statistical analysis was carried out by institute b. Methods of primary statistical analysis and rules to adjust for multiple testing were specified in a statistical analysis plan based on a data review before unblinding. A linear trend test based on a linear mixed model was used for outcomes of comet assay and exact permutation test for linear trend for all other outcomes. It was ascertained that only outcomes with a significant SAR trend found by at least two of three analyzing laboratories indicated a substantiated suspicion of an exposure effect. On the basis of these specifications, none of the nine end points tested for SAR trend showed a significant and reproducible exposure effect. Highly significant differences between sham exposures and positive controls were detected by each analyzing laboratory, thus validating the study. In conclusion, the results show no evidence of a genotoxic effect induced by RF EMF (GSM, 1,800 MHz).

Performance and limits of KNN-based positioning methods for GSM networks over leaky feeder in underground tunnels

Localisation techniques have long been of major importance for safety systems and a lot of research has been conducted in the distributed computing field regarding its functionality and reliability. In the specific scenario of long yet narrow tunnels existing at CERN, localisation methods will enable a number of applications and processes to substantially reduce human intervention. In this article, we evaluate the use of fingerprinting techniques with GSM signal available throughout the LHC tunnel via a radiating cable and compare some methods to estimate the location. In the tests, 16 variants of the K-Nearest Neighbour algorithm, employing different distance weighting methods and fingerprint grouping functions, are taken into consideration and their performance is assessed with a specific rating algorithm. The existing GSM infrastructure and tunnel conditions seem to be favourable to the adoption of these fingerprinting methods. Nevertheless, significant variations in the signal have been observed which might be traced back to the presence of bulky equipment and different operational states of the accelerator. The performance limits of these fingerprinting methods are discussed for the current scenario and, based on that, an outlook for future research is given aiming at improving the system's accuracy under such challenging conditions.

Long Distance Pipeline Cathodic Protection Test System Based on GSM

With the mode of combining long distance pipeline cathodic protection method and GSM communication technology, the System realizes automatic pipeline testing and transmission of test data, and has succeeded in solving transmission of test data at the area without GSM signals.

Exploring the Physical-layer Identification of GSM Devices

In this work, we study the physical-layer identification of GSM devices. For our exploration, we build an ad-hoc acquisition setup that collects GSM signals during voice calls. We collect signals from a population of 18 mobile devices and build fingerprints by considering both the transient and the data parts of the acquired signals. Our results show that devices of different models and manufacturers can be identified with high accuracy (0% identification error) by exploiting transient-based fingerprints. Same model and manufacturer devices could also be identified by using transient-based fingerprints: we find an identification error between 0 and 8% depending on the considered device set. We also find that the built transient-based fingerprints are sensitive to the device transmission power, but only partially to the device position with respect to our acquisition setup antenna. This possibly enables defensive (e.g., access control) applications. Although with less accuracy with respect to transient-based fingerprints, data-based fingerprints could also be used to identify same model and manufacturer devices. However, these seem to be sensitive to the device position.

Effects of mobile phone signals over BOLD response while performing a cognitive task

Objective The aim of this study was to investigate the effects induced by an exposure to a GSM signal (Global System for Mobile Communication) on brain BOLD (blood-oxygen-level dependent) response, as well as its time course while performing a Go–NoGo task. Methods Participants were tested twice, once in presence of a “real” exposure to GSM radiofrequency signal and once under a “sham” exposure (placebo condition). BOLD response of active brain areas and reaction times (RTs) while performing the task were measured both before and after the exposure. Results RTs to the somatosensory task did not change as a function of exposure (real vs sham) to GSM signal. BOLD results revealed significant activations in inferior parietal lobule, insula, precentral and postcentral gyri associated with Go responses after both ‘‘real’’ and ‘‘sham’’ exposure, whereas no significant effects were observed in the ROI analysis. Conclusions The present fMRI study did not detect any brain activity changes by mobile phones. Also RTs in a somatosensory task resulted unaffected. Significance No changes in BOLD response have been observed as a consequence of RF-EMFs exposure.