Mobile telephony

About: Mobile telephony is a research topic. Over the lifetime, 38008 publications have been published within this topic receiving 553646 citations.

Method and system for providing a temporary subscriber identity to a roaming mobile communications device

Abstract: A system provides a service to mobile devices that permits the mobile devices to substantially avoid roaming charges while roaming in visited networks A temporary subscriber identity (TSI) server receives a TSI request message from a TSI client operating on a roaming mobile device If available, a temporary service identity is returned to the TSI client, which registers the mobile communications device with a specified service provider as a home subscriber using the temporary service identity

A Generalized Subspace Approach for Mobile Positioning With Time-of-Arrival Measurements

Abstract: The problem of locating mobile terminals has received considerable attention particularly in the field of wireless communications. In this correspondence, a simple subspace-based algorithm for mobile positioning with the use of time-of-arrival measurements deduced from signals received at three or more reference base stations is derived and analyzed. It is shown that the proposed approach is a generalization of the mobile localization method based on multidimensional similarity analysis. Computer simulations are included to contrast the estimator performance with Cramer-Rao lower bound.

Enabling pervasive computing with smart phones

Abstract: Mobile telephony's technical and market success in Europe attracted researchers' interest in mobile systems. Some researchers began investigating appropriate architectures for providing information services to cellular mobile telephony users, and the quest for the "killer" third-generation (3G) mobile telephony application dominated the EU Information Society Technology research program. Dozens of projects launched to pursue this aim, and we were intimately involved in several of them. We report here on lessons learned during our involvement in this research and suggest how pervasive computing might benefit from this experience. Although some business and practical challenges exist, mobile phones could serve as information service end points, control devices for ubiquitous systems, network hubs for personal and body area networks, and ID tokens.

Traffic incidents processing system and method for sharing real time traffic information

Abstract: A traffic incidents processing system for sharing real time traffic information between a plurality of users connected via a network. The system includes a central computer system, operatively connected to a wide area network such as the Internet, a multiplicity of mobile communication devices, capable of determining their geographical location, and are operatively connected to a wide area network such as the Internet, and are capable of transmitting location based traffic information to the said central computer system. The central computer system continuously maintains updated database of traffic information. The central computer system is capable of analyzing, screening and assessing the reliability of the traffic information, detect a traffic situation, and provide customized, real time traffic alerts to a plurality of users connected to a network and to mobile communication devices such as cellular telephones via the wide area network as well as via short messaging service SMS, multimedia messaging system MMS, or any other data protocol capable of communicating with mobile devices. The central computer system is further capable of storing a history of routes traveled by users, and determine an optimal route from any originating point to any destination point by analyzing the stored routes and construct the optimal route using the most frequently traveled segments found in the stored routes database, and the realtime traffic information that is known to the system.

TDD-CDMA for the 4th generation of wireless communications

Abstract: This article discusses an evolutionary TDD mode of CDMA-based path for 3.5G/4G systems. This technology has already been the basis of two 3G standards: TD-CDMA and TD-SCDMA with a synchronous uplink. Several techniques have been developed that allow TDD-CDMA-based systems to transmit at rates usually associated with 3.5G to 4G, up to 10-20 Mbit/s with wide area coverage. The present TDD-CDMA-based 3G standards are evolving to provide these higher rates, while fully retaining the coverage and mobility associated with, and expected from, the present mobile communications systems. This article discusses how TDD-CDMA specific techniques facilitate delivering services at data rates associated with 3.5G and 4G. We review how TDD-CDMA can provide for asymmetric uplink and downlink transmissions, facilitate deployment of advanced antennas for improved downlink coverage, and enable provision of advanced receiver techniques in base stations and mobiles. We also discuss how these techniques affect systems capacity in full packet-switched IP-based systems. We then discuss 4G TDD CDMA systems: those with different modulation techniques for uplink and downlink communications. These are generally based on a multicarrier mode of CDMA, and may incorporate OFDM technique.