Search results for "Telephony"
showing 10 items of 84 documents
Keynote talk 3: From basics to advanced modelling and simulation techniques for mobile radio channels
2011
From the earliest beginnings of mobile communications to the present time, there has always been a high demand for realistic mobile radio channel models. This demand is driven by the fact that channel models are indispensable for the performance evaluation, parameter optimisation, and test of mobile communication systems. Channel modelling and simulation techniques are therefore of great importance for electronics and telecommunication engineers who are involved in the development of present and future mobile communication systems. This presentation will start with a review of the basic principles of mobile radio channel modelling and gradually moves to more advanced modelling and simulatio…
PCP: An End-to end Measurement Based Call Admission Control for Real-Time Services Over IP Networks
2000
Distributed end-to-end measurement based connection admission control mechanisms have been recently proposed. The goal of these schemes is to provide tight QoScon trol on a per connection basis by means of measurements taken by the edge nodes and priority based forwarding procedure at internal nodes. Since the additional flows handling procedures are implemented at the border routers and the forwarding mechanisms are for flows aggregates only, the approach is fully scalable and compatible with the IETF Differentiated Service proposal. The aim of this paper is to propose specific schemes and to investigate the advantages and limits of the approach by analyzing the basic mechanisms and evalua…
Delay-oriented data traffic migration in maritime mobile communication environments
2012
Maritime ship-to-shore communication has to satisfy different user requirements while suffering dynamic communication circumstances. Satellite networks are the primary means to communicate between ship and shore. The idea of compensating the deficiency of satellite communication with other terrestrial networks is not new. However, focus was often on how to keep users always best connected, without considering respective application needs or the potential disconnections. In this paper, we propose a delay-oriented satellite data traffic migration solution, exploiting the route repetitiveness and predictability of ships, leveraging the delay tolerance of many communication applications, with t…
The MOBI-Kids Study Protocol: Challenges in Assessing Childhood and Adolescent Exposure to Electromagnetic Fields from Wireless Telecommunication Tec…
2014
The rapid increase in mobile phone use in young people has generated concern about possible health effects of exposure to radiofrequency (RF) and extremely low frequency (ELF) electromagnetic fields (EMF). MOBI-Kids, a multinational case–control study, investigates the potential effects of childhood and adolescent exposure to EMF from mobile communications technologies on brain tumor risk in 14 countries. The study, which aims to include approximately 1,000 brain tumor cases aged 10–24 years and two individually matched controls for each case, follows a common protocol and builds upon the methodological experience of the INTERPHONE study. The design and conduct of a study on EMF exposure an…
Women, Empowerment, and Mobile Phones in the Developing World
2020
This chapter surveys and analyzes recent literature on mobile communication to examine its relationship to gender and development, more specifically how women in developing countries use and are impacted by mobile phones. Focusing on issues of power, agency, and social status, the chapter reviews how mobile telephony has been found to be implicated in patriarchal bargaining in different societies, how privacy and control are enabled through it, what benefits have been shown to accrue to women using mobile phones, and what barriers, limitations, and disadvantages of mobile use exist for women and why. The conclusion urges more gender-disaggregated analysis of mobile phone impact and use and …
Sex, social reproduction, and mobile telephony as responses to precarity in urban Tanzania
2019
The gendered effects of neoliberal economic restructuring around the world are usually studied in their most dramatic forms: cross-border migration, exploitation, resistance, and violence. This chapter examines significant transformations arising from economic restructuring in the nexus between gender, labour, and urban space — transformations in which mobile technologies are deeply implicated. It explores how mobile phones are used by the poor for day-to-day survival in Tanzania’s largest city. The chapter shows how gendered economic bargains are negotiated at the very bottom of a survival economy located within the dynamics of a globalized economic system. An important characteristic of m…
Mobile telephony in emerging markets: The importance of dual-SIM phones
2020
Abstract A substantial share of customers in emerging markets use dual-SIM phones and subscribe to two mobile networks. A primary motive for so called multi-simming is to take advantage of cheap on-net services from both networks. In our modelling effort, we augment the seminal model of competing telephone networks á la Laffont, Rey and Tirole (1998b) by a segment of flexible price hunters that may choose to multi-sim. According to our findings, in equilibrium, the networks set a high off-net price in the linear tariffs to achieve segmentation. This induces the price hunters to multi-sim. We show that increased deployment of dual-SIM phones may induce a mixing equilibrium with high expected…
Practical procedure for verification of compliance of digital mobile radio base stations to limitations of exposure of the general public to electrom…
2002
In the last few years, society has witnessed the installation of an ever increasing number of radio base stations as a necessity for handling new capabilities and services to the large number of users. This rapid development of wireless networks, however, has induced a marked mistrustful attitude in people, who fear possible biological effects of electromagnetic emissions from mobile communications base stations. While there are guidelines on the limitation of human exposure to electromagnetic fields (emf ), there is no harmonised standard measurement procedure to evaluate compliance with the limits on exposure in the vicinity of a base station. The measurement procedure has to be practical…
Effect of Channel-Quality Indicator Delay on HSDPA Performance
2007
This paper evaluates the effect of the channel estimation inaccuracy on the performance of an HSDPA system. This study provides some results from system level simulations that have been conducted over a very complete dynamic simulator which models an HSDPA system full compliant with specifications. This emulator allows performing multi-user transmission and link adaptation with a limited modulation and coding scheme (MCS) selection based on the channel quality indicator (CQI) modes. Many factors such as the user equipment (UE) speed, the employed scheduling algorithm or the traffic load have been considered in the assessment. Moreover the intrinsic constraints of a WCDMA system like HSDPA h…
Improved GNSS positioning exploiting a vehicular P2P infrastructure
2010
This paper considers the possibility to exploit external altitude measurements to improve the performance of a Kalman based GNSS receiver. The altitude measurements are provided by means of a peer to peer network, that is supposed to be based on the evolution of the 802.11 standard for the vehicular environment, namely the WAVE (802.11p). The performance of such a system are investigated for different characteristics of the aiding measurement and for a different number and disposals of the aiding peers. The aiding measurement is obtained starting from the altitude measurements that the other peers in the network send to the aided user. The experiments highlight the need for a parameter that…