scispace - formally typeset
Search or ask a question

Showing papers on "GSM published in 2009"


Proceedings ArticleDOI
04 Nov 2009
TL;DR: TailEnder is developed, a protocol that reduces energy consumption of common mobile applications and aggressively prefetches several times more data and improves user-specified response times while consuming less energy.
Abstract: In this paper, we present a measurement study of the energy consumption characteristics of three widespread mobile networking technologies: 3G, GSM, and WiFi. We find that 3G and GSM incur a high tail energy overhead because of lingering in high power states after completing a transfer. Based on these measurements, we develop a model for the energy consumed by network activity for each technology.Using this model, we develop TailEnder, a protocol that reduces energy consumption of common mobile applications. For applications that can tolerate a small delay such as e-mail, TailEnder schedules transfers so as to minimize the cumulative energy consumed meeting user-specified deadlines. We show that the TailEnder scheduling algorithm is within a factor 2x of the optimal and show that any online algorithm can at best be within a factor 1.62x of the optimal. For applications like web search that can benefit from prefetching, TailEnder aggressively prefetches several times more data and improves user-specified response times while consuming less energy. We evaluate the benefits of TailEnder for three different case study applications - email, news feeds, and web search - based on real user logs and show significant reduction in energy consumption in each case. Experiments conducted on the mobile phone show that TailEnder can download 60% more news feed updates and download search results for more than 50% of web queries, compared to using the default policy.

1,239 citations


Proceedings ArticleDOI
19 Apr 2009
TL;DR: An energy-efficient localization framework called EnLoc is developed, driven by measurements from Nokia N95 phones, that characterizes the optimal localization accuracy for a given energy budget, and develops prediction- based heuristics for real-time use.
Abstract: A growing number of mobile phone applications utilize physical location to express the context of information. Most of these location-based applications assume GPS capabilities. Unfortunately, GPS incurs an unacceptable energy cost that can reduce the phone's battery life to less than nine hours. Alternate localization technologies, based on WiFi or GSM, improve battery life at the expense of localization accuracy. This paper quantifies this important tradeoff that underlies a range of emerging services. Driven by measurements from Nokia N95 phones, we develop an energy-efficient localization framework called EnLoc. The framework characterizes the optimal localization accuracy for a given energy budget, and develops prediction- based heuristics for real-time use. Evaluation on traces from real users demonstrates the possibility of achieving good localization accuracy for a realistic energy budget.

266 citations


Journal ArticleDOI
TL;DR: The issue of LTE physical cell identity confusion associated with inbound handover to femtocells (which is expected to be resolved within the 3GPP Release 9 timeline) is discussed.
Abstract: Femtocells have become an attractive device for operators to offer extended services on their licensed UMTS/LTE spectrum. In this article we focus on the access control strategy - a crucial aspect for operators to give preferential access to femtocells for their subscribers. The general issue of supporting femtocells in pre-Release 8 UMTS networks with pre-Release 8 UE is first outlined in order to help the reader understand the motivation behind some concepts introduced in 3GPP Release 8 to support femtocells. A description of the femtocell access control strategy for UMTS and LTE is then provided based on 3GPP Release 8 specifications. Finally, the issue of LTE physical cell identity confusion associated with inbound handover to femtocells (which is expected to be resolved within the 3GPP Release 9 timeline) is discussed.

221 citations


Patent
07 Jan 2009
TL;DR: In this article, a distributed activity coordinator modifies the activity pattern of multiple radio access communication devices (RACDs) collocated in a single device such as a mobile station.
Abstract: A novel and useful apparatus for and method of coordinating the allocation of transmission and reception availability and/or unavailability periods for use in a communications device incorporating collocated multiple radios. The mechanism provide both centralized and distributed coordination to enable the coordination (e.g., to achieve coexistence) of multiple radio access communication devices (RACDs) collocated in a single device such as a mobile station. A distributed activity coordinator modifies the activity pattern of multiple RACDs. The activity pattern comprises a set of radio access specific modes of operation, (e.g., IEEE 802.16 Normal, Sleep, Scan or Idle modes, 3GPP GSM/EDGE operation mode (PTM, IDLE, Connected, DTM modes), etc.) and a compatible set of wake-up events, such as reception and transmission availability periods. To prevent interference and possible loss of data, a radio access is prevented from transmitting or receiving data packets while another radio access is transmitting or receiving. In the event two or more RATs desire to be active at the same time, the mechanism negotiates an availability pattern between the MS and a corresponding BS to achieve coordination between the RATs.

190 citations


01 Jan 2009
TL;DR: The present document may be made available in more than one electronic version or in print and the reference version is the Portable Document Format (PDF), in case of existing or perceived difference in contents between such versions.
Abstract: The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI Secretariat. No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media.

168 citations


Journal ArticleDOI
TL;DR: A small-size printed loop antenna with an internal printed matching circuit capable of GSM/DCS/PCS/UMTS operation in the mobile phone is proposed and its radiation performances including the SAR (specific absorption rate) results are studied.
Abstract: A small-size printed loop antenna with an internal printed matching circuit capable of GSM/DCS/PCS/UMTS operation in the mobile phone is proposed. The antenna comprises an 85-mm long folded loop strip and an internal printed matching circuit encircled therein and formed by a coupling strip and an inductive strip. The loop strip is excited by the coupling strip to generate a 0.25 lambda resonant mode at about 900 MHz for GSM operation. For the inductive strip, it effectively causes a wideband higher order mode at about 1900 MHz for DCS/PCS/UMTS operation. Further, the antenna shows a uniplanar structure and requires a very small printed area of 170 mm2 on the system circuit board of the mobile phone, making it easy to fabricate at low cost. Details of the proposed antenna and its radiation performances including the SAR (specific absorption rate) results are studied.

162 citations


Patent
01 Oct 2009
TL;DR: In this paper, a smart miniature circuit breaker (SMCB) is used to monitor electricity consumption at a circuit level in new and existing domestic consumer units or industrial distribution boards.
Abstract: A smart miniature circuit breaker (SMCB) can be used to monitor electricity consumption at a circuit level in new and existing domestic consumer units or industrial distribution boards. The SMCB comprises: a miniature circuit breaker (MCB) 2; an instantaneous current measurement device, wireless transceiver 6 and hard wired communication means 7, that can be used in any combination to transmit data and receive acknowledgement and configuration data; and a store to buffer data. The SMCB reads the usage of electricity in the circuit, at a user defined rate, and reports it to a local coordinator 4 which incorporates local data storage, processing capability and means for remote connectivity via an IP gateway such as Wifi, GSM or Ethernet network. The wireless transceiver can operate in a licence free communication spectrum at 433 MHz, 868MHz or 2.4GHz and the circuit current can be measured and communicated at a frequency set by the coordinator unit.

155 citations


Patent
05 Aug 2009
TL;DR: In this paper, a system and method to intercept traffic at standard interface points as defined by Cellular/Wireless networks (GSM/GPRS, 3G/UMTS/HSDPA/HSUPA, CDMA, WIMAX, LTE), emulate the respective protocols on either side of the interception point, extract user/application payloads within the intercepted packets, perform optimizations, and reencapsulate with the same protocol, and deliver the content transparently is disclosed.
Abstract: A system and method to intercept traffic at standard interface points as defined by Cellular/Wireless networks (GSM/GPRS, 3G/UMTS/HSDPA/HSUPA, CDMA, WIMAX, LTE), emulate the respective protocols on either side of the interception point, extract user/application payloads within the intercepted packets, perform optimizations, and re-encapsulate with the same protocol, and deliver the content transparently is disclosed. The optimizations include but are not limited to Content Caching, prediction & pre-fetching of frequently used content, performance of content-aware transport optimizations (TCP, UDP, RTP etc.) for reducing back-haul bandwidth, and improvement of user experience. An additional embodiment of the current invention includes injecting opportunistic content (location based, profile based or advertisement content) based on the information derived while monitoring control plane protocols.

152 citations


Journal ArticleDOI
TL;DR: The HACS system provides security against intrusion as well as automates various home appliances using SMS and uses GSM technology thus providing ubiquitous access to the system for security and automated appliance control.
Abstract: This paper mainly focuses on the controlling of home appliances remotely and providing security when the user is away from the place. The system is SMS based and uses wireless technology to revolutionize the standards of living. This system provides ideal solution to the problems faced by home owners in daily life. The system is wireless t herefore more adaptable and cost-effective. The HACS system provides security against intrusion as well as automates various home appliances using SMS. The system uses GSM technology thus providing ubiquitous access to the system for security and automated appliance control.

143 citations


Proceedings ArticleDOI
17 May 2009
TL;DR: Results of power and energy consumption measurements conducted on mobile phones for 2G and 3G networks for text messaging and voice services imply that mobile phones should switch the network in dependency of the service used to save the maximum amount of energy.
Abstract: Over the last years mobile phones had a remarkable evolution. From a simple device for voice communication, it became a full blown multimedia device with multiple features and appealing services. In parallel with the introduction of novel services, mobile devices became more and more energy-hungry reducing the operational time for the user. To extend the battery life of mobile phones is one of the top priorities for mobile phones' manufacturers. This paper presents results of power and energy consumption measurements conducted on mobile phones for 2G and 3G networks. The services under investigation were text messaging, voice and data. The paper reports larger energy consumption in 3G networks for text messaging and voice services than energy consumption in 2G networks. On the other side the 3G networks become more energy friendly when large volumes of data have to be downloaded. The results imply that mobile phones should switch the network in dependency of the service used to save the maximum amount of energy. As this handover consumes energy, we include its analysis in our measurements.

140 citations


Book
07 Jun 2009
TL;DR: In this paper, the authors present an overview of Antennas for WLAN (WiFi) and WCDMA (CDMA, GSM) applications, including RFID/UWB Positioning Index.
Abstract: Preface Acknowledgments Introduction Chapter 1. Fundamentals of Antennas Chapter 2. Base Station Antennas for Mobile Radio Systems Chapter 3. Antennas for Mobile Communications: CDMA, GSM, and WCDMA Chapter 4. Advanced Antennas for Radio Base Stations Chapter 5. Antennas Issues and Technologies for Enhancing System Capacity Chapter 6. New Unidirectional Antennas for Various Wireless Base Stations Chapter 7. Antennas for WLAN (WiFi) Applications Chapter 8. Antennas for Wireless Personal Area Network (WPAN) Applications: RFID/UWB Positioning Index

Book
01 Jan 2009
TL;DR: By describing the critical decisions and the phases of the development of GSM, this key text explains how the GSM initiative became a success in Europe and how it evolved to the global mobile communication system.
Abstract: From the Publisher: GSM (Global System for Mobile communication) provides a service to more than 500 million users throughout 168 countries worldwide. It is the world market leader serving 69 % of all mobile digital users and is currently evolving into UMTS (Universal Mobile Telecommunication System). By describing the critical decisions and the phases of the development this key text explains how the GSM initiative became a success in Europe and how it evolved to the global mobile communication system. Initially the strategy and technical specifications were agreed for Europe and the subsequent evolution to a global solution was achieved by incorporating all non-European requirements and by inviting all committed parties worldwide to participate. The process started in 1982 and the first GSM networks went into commercial service in 1992. The first UMTS networks are expected in 2002 and the fourth generation discussions have begun. *Presents a complete technical history of the development of GSM and the early evolution to UMTS *Clarifies the creation of the initial GSM second generation system in CEPT GSM, the evolution to a generation 2.5 system in ETSI SMG and the evolution to the Third Generation (UMTS) in ETSI SMG and 3GPP *Covers all of the services and system features together with the working methods and organisational aspects GSM and UMTS provides an interesting and informative read and will appeal to everyone involved in the mobile communications market needing to know how GSM and UMTS technologies evolved. The accompanying CD-ROM provides nearly 500 reference documents including reports of all standardisation plenary meetings, strategy documents, keydecisions, the GSM Memorandum of Understanding and the report of the UMTS Task Force.

Patent
27 Apr 2009
TL;DR: In this article, an intelligent activation module can be programmed with a variety of settings including speed, map deltas, final destination information, or settings as pre-determined by a user of the mobile device.
Abstract: A programmable intelligent activation module to intelligently allow access to GPS resources is provided. In accordance with pre-programmed settings, an intelligent activation module will control the frequency by which a GPS module is allowed to access a GPS or GSM network in order to acquire location information of a mobile device equipped with GPS equipment. By controlling access to a GPS or GSM network, network resources such as bandwidth are conserved unless actually needed as is determined by the intelligent activation module. Similarly, battery resources for the mobile device are also conserved in that unnecessary activation of the GPS module is prevented until such activation is actually needed. The intelligent activation module can be programmed with a variety of settings including speed, map deltas, final destination information, or settings as pre-determined by a user of the mobile device.

Journal ArticleDOI
TL;DR: This paper presents the first design of a low-cost wakeup radio made out of standard components, and includes a specialised low-power microcontroller filtering out interference (e.g. GSM signals), which makes it practical for use in many real-world settings.
Abstract: In many wireless sensor network scenarios, battery-powered nodes must operate for years, which necessitate the need for advanced power management of the radio. In this paper, we pursue the idea of using a second, ultra low-power radio that can be used to trigger a remote interrupt, so that a receiver can fire up its primary radio to engage in efficient high-speed communication with the sender. Wakeup radio avoids the complex bookkeeping associated with energy-efficient MAC protocols, but at the price of additional hardware. We present the first design of a low-cost wakeup radio made out of standard components. Our working prototype implementation operates in the European license-free 868 MHz band, and includes a specialised low-power microcontroller filtering out interference (e.g. GSM signals), which makes it practical for use in many real-world settings.

Patent
29 Dec 2009
TL;DR: In this paper, the authors provide a single E.164 number for voice and data call redirection and telephony services such as caller identification, regardless of in which type of network a dual mode mobile device operates.
Abstract: Systems and methods provide a single E.164 number for voice and data call redirection and telephony services such as caller identification, regardless of in which type of network a dual mode mobile device operates. When the dual mode device registers and is active in a GSM network, temporary routing and status updates are triggered and resultant information is maintained in both networks. A mobile terminated call is routed through an enterprise WLAN with call control within the enterprise being handled by SIP or H.323 signaling, and the call is redirected to the mobile device in the GSM network, where call control is assumed by the SS7 network. Services are provided using the protocols native to the active network, and the single E.164 is used consistently along with or lieu of the temporary routing information for subscriber identity specific functions, such as caller identification and voice mail.

Patent
28 Jun 2009
TL;DR: In this paper, the authors present a method for mediating SMS messages comprising of configuring electronic hardware on the wireless mobile communications device to implement a firewall on the WMS device, the firewall configured to identify and optionally mediate infrastructure SMS messages.
Abstract: Methods, systems, and software for mediating SMS messages, and especially type 0 SMS messages, in a wireless mobile communications device configured to send and receive data using a GSM protocol and including a subscriber identity module (“SIM”) including electronic hardware and computer software executed by the hardware such that the SIM is configured to send, receive, and process messages using a Short Message System (“SMS”) between the wireless mobile communications device and a communications network One aspect includes a method for mediating SMS messages comprising: configuring electronic hardware on the wireless mobile communications device to implement a firewall on the wireless mobile communications device, the firewall configured to identify and optionally mediate infrastructure SMS messages

Patent
17 May 2009
TL;DR: In this paper, the authors present an environment which allows a user to quickly and efficiently switch between service provider accounts supporting communications over both GSM and CDMA communication networks by re-programming a mobile device equipped with a software defined radio based chipset module.
Abstract: Methods and systems enable mobile devices equipped with software defined radio based chipset modules to seamlessly re-program the mobile device to operate on any of a variety of service provider networks. By re-programming a mobile device equipped with software defined radio based chipset module, the mobile device can support communications over both GSM and CDMA communication networks. An environment is provided which allows a user to quickly and efficiently switch between service provider accounts supporting communications.

Journal ArticleDOI
TL;DR: In this article, the authors examined the patents filed in the standardization of UMTS, the third-generation mobile phone technology developed under sponsorship of the European Telecommunications Standards Institute (ETSI) and others, using a patent policy developed in response to issues faced in the earlier GSM (nee Group Special Mobile) standardization.

Proceedings ArticleDOI
29 May 2009
TL;DR: A single-chip transceiver that operates as a multimode multiband radio and eliminates the inter-stage receive / transmit SAW filters is presented.
Abstract: There has been an increased demand for 3G cell phones that support multiple bands of operation and are backward compatible with the 2G/2.5G standard to provide coverage where 3G networks have not yet been fully deployed. The transceiver design for such a handset becomes complicated with the need for separate transceivers for 3G and 2G/2.5G [1,2] or for multiple inter-stage receive / transmit SAW filters [3]. A single-chip transceiver that operates as a multimode multiband radio and eliminates the inter-stage receive / transmit SAW filters is presented. Figure 6.3.1 shows the block diagram of the transceiver with 7 primary and 4 diversity bands in WCDMA, and quad band in GSM. The transceiver is designed to operate in any of the UTRA bands 1 to 10, with the exception of band 7. It supports HSDPA (Cat 1–12), HSUPA (Cat 1–6), EGPRS (Classes 1–12, 30–39), and compressed mode of EGPRS / WCDMA operation. The transceiver is compliant with 3G DigRF interface 3.09.

Journal ArticleDOI
TL;DR: The measurements indicate a potentially large improvement using UMTS signalling data compared with GSM regarding handover location accuracy and can be used to generate real-time traffic information with higher quality and extend the geographic usage area for cellular-based travel time estimation systems.
Abstract: Field measurements from the GSM and UMTS networks are analysed in a road traffic information context. The measurements indicate a potentially large improvement using UMTS signalling data compared with GSM regarding handover location accuracy. These improvements can be used to generate real-time traffic information with higher quality and extend the geographic usage area for cellular-based travel time estimation systems. The results confirm previous reports indicating that the technology has a large potential in GSM and also show that the potential might be even larger and more flexible using UMTS. Assuming that non-vehicle terminals can be filtered out, that vehicles are tracked to the correct route and that handovers can be predicted correctly, a conclusion from the experiments is that the handover location accuracy in both GSM and UMTS will be sufficient to estimate useful travel times, also in urban environments. In a real system, these tasks are typically very challenging, especially in an urban environment. Further, it is reasonably established that the location error will be minor for the data obtained from UMTS.

Proceedings ArticleDOI
26 Apr 2009
TL;DR: A unified framework that encompasses UMTS and GPRS data collection in addition to GSM, and prospectively combines passive and active monitoring techniques is outlined, which identifies the main research challenges that must be faced in designing and implementing such an intelligent road traffic estimation system via third-generation cellular networks.
Abstract: In this contribution we address the problem of using cellular network signaling for inferring real-time road traffic information. We survey and categorize the approaches that have been proposed in the literature for a cellular-based road monitoring system and identify advantages and limitations. We outline a unified framework that encompasses UMTS and GPRS data collection in addition to GSM, and prospectively combines passive and active monitoring techniques. We identify the main research challenges that must be faced in designing and implementing such an intelligent road traffic estimation system via third-generation cellular networks.

Journal ArticleDOI
TL;DR: It is reported for the first time that UMTS MWs affect chromatin and inhibit formation of DNA double‐strand breaks co‐localizing 53BP1/γ‐H2AX DNA repair foci in human lymphocytes from hypersensitive and healthy persons and it is confirmed that effects of GSM MWs depend on carrier frequency.
Abstract: We have recently described frequency-dependent effects of mobile phone microwaves (MWs) of global system for mobile communication (GSM) on human lymphocytes from persons reporting hypersensitivity to electromagnetic fields and healthy persons Contrary to GSM, universal global telecommunications system (UMTS) mobile phones emit wide-band MW signals Hypothetically, UMTS MWs may result in higher biological effects compared to GSM signal because of eventual "effective" frequencies within the wideband Here, we report for the first time that UMTS MWs affect chromatin and inhibit formation of DNA double-strand breaks co-localizing 53BP1/gamma-H2AX DNA repair foci in human lymphocytes from hypersensitive and healthy persons and confirm that effects of GSM MWs depend on carrier frequency Remarkably, the effects of MWs on 53BP1/gamma-H2AX foci persisted up to 72 h following exposure of cells, even longer than the stress response following heat shock The data are in line with the hypothesis that the type of signal, UMTS MWs, may have higher biological efficiency and possibly larger health risk effects compared to GSM radiation emissions No significant differences in effects between groups of healthy and hypersensitive subjects were observed, except for the effects of UMTS MWs and GSM-915 MHz MWs on the formation of the DNA repair foci, which were different for hypersensitive (P 005) The non-parametric statistics used here did not indicate specificity of the differences revealed between the effects of GSM and UMTS MWs on cells from hypersensitive subjects and more data are needed to study the nature of these differences


Journal ArticleDOI
TL;DR: This poster describes a means of localization where phones sense their surroundings, and use this ambient information to classify their location, and postulates that different surroundings have photo-acoustic fingerprints, that can be sensed and used for localization.
Abstract: Proliferating mobile phones provide a foundation for revolutionary innovations in peoplecentric computing. Numerous applications are on the rise, many of which exploit the phone's location as the primary indicator of context. We argue that existing physical localization schemes based on GPS/WiFi/GSM have limitations which make them impractical for use in such applications. Instead, in this poster we describe a means of localization where phones sense their surroundings, and use this ambient information to classify their location. Put differently, we postulate that different surroundings have photo-acoustic fingerprints, that can be sensed and used for localization. We demonstrate the feasibility using Tmote Invent motes that have light and sound sensors. Our ongoing work is extending SurroundSense to the mobile phone platform, and exploiting additional sensors (such as accelerometers and compasses) towards even better localization.

Journal ArticleDOI
TL;DR: An improved IP-based vertical handover technology for mobile WiMAX, 3GPP legacy systems, and 3G Long Term Evolution is presented, which is based on existing optimized handover techniques between mobileWiMAX and 3GsPP accesses and introduces an additional network element called the DFF that eliminates the data loss during VHO execution.
Abstract: Recent mobile devices are integrated with multiple network interfaces. Users want their devices connected to the network anytime anywhere. It is highly feasible for a user to change connection to another network for users that leave the service area of its current serving network, where handover needs to be executed seamlessly such that ongoing service sessions are not interrupted. The handover operation not only requires switching the interfaces within a device but also involves seamless reconfiguration of the supporting networks. In this article, an improved IP-based vertical handover technology for mobile WiMAX , 3GPP legacy systems (i.e., Global System for Mobile communications and Universal Mobile Telecommunications System), and 3G Long Term Evolution is presented, which is based on existing optimized handover techniques between mobile WiMAX and 3GPP accesses. Formerly proposed 3GPP WiMAX optimized VHO solutions introduced new elements, such as the forward attachment function and access network discovery and selection function. The ANDSF supports the discovery of target access, and the FAF provides the functionality that authenticates the UE before the execution of VHO. However, the previous technique has limitations that result in data loss and abnormal disconnection to the source access. This article provides a solution by introducing an additional network element called the data forwarding function (DFF) that eliminates the data loss during VHO execution. In addition, the DFF resolves the problem of abrupt disconnection to the source network. The simulation results show that the proposed VHO technique is effective in minimizing data loss during VHO execution between mobile WiMAX and 3GPP networks. As the proposed solution of this article is an IP based handover solution, it can be similarly applied to other communication networks.

Proceedings ArticleDOI
01 Dec 2009
TL;DR: The proposed solid waste monitoring and management system using radio frequency identification (RFID) associate with intelligent systems would provide in time solid waste collection, tracking the vehicle position through the GIS database and also overcome the disadvantages.
Abstract: This paper deals with the solid waste monitoring and management system using radio frequency identification (RFID) associate with intelligent systems. The system consists of RFID system, mobile communication like GSM and geographical information system (GIS) for tracking vehicle position. The proposed system would be able to monitor the solid waste collection process and management the overall collection process. It would provide in time solid waste collection, tracking the vehicle position through the GIS database and also overcome the disadvantages such as usage of minimum route, low fuel cost, clean environment and available vehicle. The technologies that would be used in the proposed system are good enough to ensure the practical and perfect for solid waste collection process monitoring and management for green environment.

Journal ArticleDOI
TL;DR: This paper presents a probabilistic location system using a wider-covered and longer-lived FM infrastructure and finds that the spatial separation of GSM signal decreases when the signal level is weaker than -90 dBm, and FM reports a better accuracy than GSM even with the fewer channels.
Abstract: Recent mobile devices have already contained a low-cost FM receiving function due to the continuing improvements in the device manufacturing. This paper shows that positioning based on FM signal is an alternative radio option while meeting the FCC requirement. We present a probabilistic location system using a wider-covered and longer-lived FM infrastructure. The performance is evaluated in two different metropolitan-scale environments including National Taiwan University (NTU) and Wen-Shan rural area. Both results show that the FM based location system not only satisfies the FCC requirement but also provides a comparable or even better performance to GSM based solution. Moreover, we completely analyze the realistic radio measurements of FM and GSM from four perspectives including temporal variation, spatial separation, measurement correlation and spectrum allocation. Most FM measurements are observed to provide a lower temporal variation but a weaker spatial separation than GSM. Fortunately, we discover that the lack of spatial separation can be compensated by adding additional sensed channels. This property is useful especially for a rural area where the available GSM base stations are limited and distant. Furthermore, we point out that the spatial separation of GSM signal decreases when the signal level is weaker than -90 dBm. At such a condition, FM reports a better accuracy than GSM even with the fewer channels.

Proceedings ArticleDOI
16 Dec 2009
TL;DR: The proposed Intelligent Traffic Light Controller is more efficient than the conventional controller in respect of less waiting time, more distance traveled by average vehicles and efficient operation during emergency mode and GSM interface and scope for further expansion.
Abstract: Present Traffic Light Controllers (TLC) are based on microcontroller and microprocessor. These TLC have limitations because it uses the pre-defined hardware, which is functioning according to the program that does not have the flexibility of modification on real time basis. Due to the fixed time intervals of green, orange and red signals the waiting time is more and car uses more fuel. To make traffic light controlling more efficient, we exploit the emergence of new technique called as "Intelligent traffic light controller". This makes the use of Sensor Networks along with Embedded Technology. The timings of Red, Green lights at each crossing of road will be intelligently decided based on the total traffic on all adjacent roads. Thus, optimization of traffic light switching increases road capacity and traffic flow, and can prevent traffic congestions. GSM cell phone interface is also provided for users those who wish to obtain the latest position of traffic on congested roads. This is a unique feature of this project which is very useful to car drivers to take an alternate route in case of congestion. The various performance evaluation criteria are average waiting time, average distance traveled by vehicles, switching frequency of green light at a junction, efficient emergency mode operation and satisfactory operation of SMS using GSM Mobile. The performance of the Intelligent Traffic Light Controller is compared with the Fixed Mode Traffic Light Controller. It is observed that the proposed Intelligent Traffic Light Controller is more efficient than the conventional controller in respect of less waiting time, more distance traveled by average vehicles and efficient operation during emergency mode and GSM interface. Moreover, the designed system has simple architecture, fast response time, user friendliness and scope for further expansion.

Patent
17 May 2009
TL;DR: In this article, the authors present an approach to track and monitor a currently activated connection manager and prevent the launching of a second connection manager while the first connection manager is still active in order to avoid potentially fatal collisions.
Abstract: Methods and systems enable mobile devices equipped with software defined radio based chipset modules to seamlessly re-program the mobile device to operate on any of a variety of service provider networks. By re-programming a mobile device equipped with software defined radio based chipset module, the mobile device can support communications over both GSM and CDMA communication networks. The re-programming of the mobile device may commence with the launching of a connection manager supporting a selected service provider. Various embodiment methods and systems are provided to track and monitor a currently activated first connection manager and prevent the launching of a second connection manager while the first connection manager is still active in order to avoid potentially fatal collisions.

Proceedings ArticleDOI
01 Dec 2009
TL;DR: This work proposes a VSN architecture to realize micro-climate monitoring based on GSM short messages and availability of GPS receivers on vehicles, and demonstrates the prototype of a ZigBee-based car network to monitor the concentration of carbon dioxide gas in areas of interest.
Abstract: Micro-climate monitoring usually requires deploying a large number of measurement tools. By adopting vehicular wireless sensor networks (VSNs), we can use fewer tools to achieve fine-grained monitoring. This work proposes a VSN architecture to realize micro-climate monitoring based on GSM short messages and availability of GPS receivers on vehicles. We demonstrate our prototype of a ZigBee-based car network to monitor the concentration of carbon dioxide (CO 2 ) gas in areas of interest. The reported data are sent to a server, which is integrated with Google Maps as our user interface. Since mobility of these vehicles is not controllable and sending short messages incurs charges, we also design an on-demand approach to adjust vehicles' reporting rates to balance between the micro-climate accuracy and the communication cost.