World Wireless Network Research Articles

A Probabilistic Indoor Localization System for Heterogeneous Devices

The extensive deployment of wireless infrastructure provides a low-cost way to track mobile users in indoor environments. Crowdsourcing has been promoted as an efficient way to reduce the labour-intensive site survey process in conventional fingerprint-based localization systems. Alongside its promising advantages, crowdsourcing produces a number of new challenges, including the heterogeneity of devices resulting in signal diversity and varying sensitivities to different access points. These are caused by different sensor specifications and antenna attenuation. These challenges are exacerbated by differences in the device populations between the survey and client phases. This paper presents a prototype model of a multiple-surveyor-multiple-client system to localize mobile users based on a crowdsourced fingerprint. A linear regression model is applied to calibrate across participating training devices. The conditional likelihood of a client observing an access point not visible in the training phase is obtained using a geometric distribution. The proposed system is able to achieve comparable localization performance. Field test results demonstrate the efficiency and benefit that the previously built radio map can be adapted to localize a new device that has not participated in the training phase with an average matching accuracy of 94% in a real world wireless network.

How not to build a world wireless network: German–British rivalry and visions of global communications in the early twentieth century

Edward Snowden’s revelations laid bare an unprecedented scale of state influence on communications technology. But government elites have frequently shaped technological development through their beliefs about potentially nefarious uses of communications. This article argues that beliefs about how other states or groups might use a technology can shape innovation. In particular, German visions about the British use of cables spurred German investment in developing wireless telegraphy. Germans imagined that the British were using cable technology to damage Germany’s reputation, spy on Germany and ‘poison’ neutral countries against the Central Powers. The German government and military at first created a colonial wireless network to bypass British cables. In World War I, however, they sought to establish a world wireless network. In the end, innovation was significantly shaped by how Germans imagined their enemies’ uses of communications technology.

Simple Traffic Prediction Mechanism and its Applications in Wireless Networks

Several studies have analyzed traffic traces collected from real world deployments of wireless networks. The vast majority of these studies have employed descriptive statistics with the aim of obtaining insights into the different aspects of wireless networks. While the contributions of all these studies are valuable, they mainly provide guidelines on design and deployment of wireless networks on a longer term perspective. The ability to predict at shorter timescales such as on the order of a few minutes empowers the network management entity with extra intelligence to optimize network performance taking into account anticipated traffic conditions. This paper proposes a simple traffic prediction mechanism using the Recursive Least Squares algorithm and highlights its applications in proactive network management. The performance of the proposed prediction mechanism is also evaluated using publicly available data set collected from a real world wireless network. Results from this study show that the RLS algorithm is capable of accurately predicting the traffic load and shows good adaptive behaviour. Moreover it is intuitively simple and results in a lightweight implementation.

What is German History? Reflections on the Role of the Nation in German History and Historiography

At the end of the sixteenth century, when the humanist and geographer Matthias Quad tried to find the boundaries for " Germany," he was forced to conclude that "there is no country in all of Christendom which embraces so many lands under one name." Two hundred years later, Goethe and Schiller wrote their famous epigram: " Germany? But where is it? I don't know how to find such a country." In 1832, Leopold von Ranke remained pessimistic that an answer to this question might easily be found: