Mobile telephony

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

Effects of User-Deployed, Co-Channel Femtocells on the Call Drop Probability in a Residential Scenario

Abstract: The femtocell concept aims to combine fixed-line broadband access with cellular telephony using the deployment of low-cost, low-power 3G base stations in the subscriber's homes. These plug-and-play residential base stations would be deployed without much consideration to cell planning on the part of the user, relying instead on inbuilt auto-configuration abilities to minimise the impact on the macro cellular network by self-provisioning parameters such as the transmit and pilot power levels. In this paper, simulations of the deployment of such femtocells in a residential scenario were performed to study its effects on the service experienced by users that are connected to the underlay macrocells. The results show that with auto-configuration, the deployment of the femtocells would not pose a significant impact on the dropped call rate, causing an additional 0.45% increase in chance of a macrocell user's call dropping in the simulation's worst case scenario. In addition the impact of such femtocell deployment on the network signalling is discussed.

Location determination of a mobile device using IEEE 802.11b access point signals

Abstract: Wireless LANs are becoming increasingly popular today, particularly those based on IEEE 802.11b standard. We study the problem of determining the location of a mobile device, which is communicating through a WLAN. We exploit the fact that the strength of the signals that a device will receive from different access points will vary with location. We build a database of signal strength information for various locations, and use this information to determine which location a given test data comes from. The problem is complicated because RF signals are affected by the noise, interference, multi-path effect, and random movement in the environment. We find that in spite of this randomness, the signal information is sufficient to detect the position of mobile device with certain error margin.

Automatically changing a mobile device configuration based on environmental condition

Abstract: The described techniques automatically change the notification mode used by a mobile communications device to alert a user of an incoming communication to the mobile communications device. The notification mode is changed in response to a detected environmental condition. The mobile communications device monitors one or more environmental conditions, such as motion, light, sound, and heat, and compares the detected level of each environmental condition to a predetermined threshold. In response to the comparison result, the mobile communications device automatically adjusts the notification mode used to alert a user to an incoming communication. In some implementations, the notification mode change may be triggered only after the environmental condition persists for a predetermined interval of time. In some implementations, the types of automatic notification mode changes used may be based on a preference of a user and may be set through the use of an Internet protocol interface.

Simulation of Rayleigh-faded mobile-to-mobile communication channels

Abstract: Mobile-to-mobile channels find increasing applications in futuristic intelligent transport systems, ad hoc mobile wireless networks, and relay-based cellular networks. Their statistical properties are quite different from typical cellular radio channels, thereby requiring new methods for their simulation. This paper proposes a "double-ring" model to simulate the mobile-to-mobile local scattering environment, and develops sum-of-sinusoids (SoS)-based models for simulating such channels. The proposed models produce waveforms having desired statistical properties with good accuracy, and also remove some drawbacks of an existing model derived by using the discrete line spectrum simulation method.

Exploiting social ties for cooperative D2D communications: a mobile social networking case

Abstract: Thanks to the convergence of pervasive mobile communications and fast-growing online social networking, mobile social networking is penetrating into our everyday life. Aiming to develop a systematic understanding of mobile social networks, in this paper we exploit social ties in human social networks to enhance cooperative device-to-device (D2D) communications. Specifically, as handheld devices are carried by human beings, we leverage two key social phenomena, namely social trust and social reciprocity, to promote efficient cooperation among devices. With this insight, we develop a coalitional game-theoretic framework to devise social-tie-based cooperation strategies for D2D communications. We also develop a network-assisted relay selection mechanism to implement the coalitional game solution, and show that the mechanism is immune to group deviations, individually rational, truthful, and computationally efficient. We evaluate the performance of the mechanism by using real social data traces. Simulation results corroborate that the proposed mechanism can achieve significant performance gain over the case without D2D cooperation.