Dynamic clusters (Dynamic Location of Phone Call Clusters)

When mobile handsets are making a call, a measurement report is sent to the serving base station periodically which includes the signal strengths to the base station and the next six strongest signals of the surrounding base stations. Motorola asked the Study Group if it was possible to say whether we could use this information to infer if phone calls occur in clusters and if it was possible to determine the locations, size and other features of these clusters. The Study Group found clusters in 'signal space,' that is, handsets reporting similar signal strengths with the same base stations and explored methods of locating these clusters geographically

Fingerprinting Smart Devices Through Embedded Acoustic Components

The widespread use of smart devices gives rise to both security and privacy concerns. Fingerprinting smart devices can assist in authenticating physical devices, but it can also jeopardize privacy by allowing remote identification without user awareness. We propose a novel fingerprinting approach that uses the microphones and speakers of smart phones to uniquely identify an individual device. During fabrication, subtle imperfections arise in device microphones and speakers which induce anomalies in produced and received sounds. We exploit this observation to fingerprint smart devices through playback and recording of audio samples. We use audio-metric tools to analyze and explore different acoustic features and analyze their ability to successfully fingerprint smart devices. Our experiments show that it is even possible to fingerprint devices that have the same vendor and model; we were able to accurately distinguish over 93% of all recorded audio clips from 15 different units of the same model. Our study identifies the prominent acoustic features capable of fingerprinting devices with high success rate and examines the effect of background noise and other variables on fingerprinting accuracy

Public safety and cognitive radio

This book gives comprehensive and balanced coverage of the principles of cognitive radio communications, cognitive networks, and details of their implementation, including the latest developments in the standards and spectrum policy. Case studies, end-of-chapter questions, and descriptions of various platforms and test beds, together with sample code, give hands-on knowledge of how cognitive radio systems can be implemented in practice. Extensive treatment is given to several standards, including IEEE 802.22 for TV White Spaces and IEEE SCC41

Partner Selection Criteria in Strategic Alliances When to Ally with Weak Partners

In many emergent markets, cross-industry alliances are necessary to develop and market new products and services. The resource-based view suggests that firms form alliances to access or acquire valuable, rare, non-imitable and non-substitutable resources, and that such access determines the level of profits. Hence, firms confronted with the choice between partners with strong versus partners with weak resource endowments should choose the former. We contest this view and argue that firms benefit from allying with weak partners at certain times. In essence, we suggest that partner selection involves assessing the relative importance of strong resource endowments and aligned strategic aspirations over time. By adopting an evolutionary approach, we show that appropriate partner selection criteria are dynamic and may involve allying with weak partners in the initial exploratory stage, with weak and/or strong partners in the development stage and with strong partners in the maturity stage. Our findings suggest that the resource-based understanding of strategic alliances should be extended to include a more profound role for a partner firm’s strategic aspiration.Strategic alliances, partner selection, resources, aspirations

Estimating network effects in mobile telephony in Germany

In this paper we analyze the demand for mobile telecommunication services in Germany in the period from January 1998 to June 2003. During this time, the subscriber base grew exponentially by about 700% while prices declined only moderately by about 41%. We believe that prices alone cannot account for such rapid diusion and network eects have inuenced the evolution of the industry. We put this view to the test by using publicly available data on subscriptions, price indices and churn rates. Using churn rates gave us approximate sales levels which enabled us to use standard methods to investigate the eect of network size on demands. Our estimates of a system of demand functions show that network eects played a signicant role in the diusion of mobile services in Germany

A game theoretic approach to energy efficient cooperative cache maintenance in MANETs

There have been an increasingly large number of mobile handsets equipped with dual or multiple network interfaces. The server interface (e.g., GPRS, EDGE, UMTS) is responsible for communicating with the network operator, while the peer interfaces (e.g., Bluetooth, IEEE 802.11) are used to connect with other computing devices. However, they are usually used separately. In this paper, we investigate the use of both network interfaces to support energy efficient data applications among mobile clients. Specifically, we proposed a fully distributed protocol for mobile handsets to form cooperative groups to maintain cache consistency with minimal communication with the network operator. Our proposed protocol takes advantage of the low power consumption and high data rate of the peer interface. The aim is to reduce the use of the server interface, which is typically slower and involves higher power consumption. Furthermore, we also consider the presence of selfish clients. It is shown that groups formed by the proposed protocol constitutes a pure Nash Equilibrium. This suggests that our protocol is robust even in the presence of selfish clients. Simulation results confirm that, given the same energy resource, mobile clients running the proposed protocol complete more queries, experience longer lifetime and achieve smaller query latency. © 2005 IEEE.published_or_final_versio

Investigations of MIMO Antenna for Smart Mobile Handsets and Their User Proximity

In this chapter, a monopole antenna with compact size, simple structure, easy to fabricate is reported which covers LTE700 (band13/14) (746–798 MHz), GSM1800 (1710–1885 MHz), PCS1900 (1850–1990 MHz), and LTE2600 (2500–2690 MHz) band based on 6-dB return loss. The proposed MIMO antenna consists of two radiating elements. The main radiating element is a composition of driven element, which is directly fed with microstrip line, and one parasitic element. The parasitic element provides the resonance at higher frequency band and the combination of driven elements and parasitic elements provide above-said frequency bands. The current distribution, far-field radiation patterns, and diversity parameters are checked out for the MIMO antenna in free space. Further performances are studied in the presence of user proximity

Baseband analog front-end and digital back-end for reconfigurable multi-standard terminals

Multimedia applications are driving wireless network operators to add high-speed data services such as Edge (E-GPRS), WCDMA (UMTS) and WLAN (IEEE 802.11a,b,g) to the existing GSM network. This creates the need for multi-mode cellular handsets that support a wide range of communication standards, each with a different RF frequency, signal bandwidth, modulation scheme etc. This in turn generates several design challenges for the analog and digital building blocks of the physical layer. In addition to the above-mentioned protocols, mobile devices often include Bluetooth, GPS, FM-radio and TV services that can work concurrently with data and voice communication. Multi-mode, multi-band, and multi-standard mobile terminals must satisfy all these different requirements. Sharing and/or switching transceiver building blocks in these handsets is mandatory in order to extend battery life and/or reduce cost. Only adaptive circuits that are able to reconfigure themselves within the handover time can meet the design requirements of a single receiver or transmitter covering all the different standards while ensuring seamless inter-interoperability. This paper presents analog and digital base-band circuits that are able to support GSM (with Edge), WCDMA (UMTS), WLAN and Bluetooth using reconfigurable building blocks. The blocks can trade off power consumption for performance on the fly, depending on the standard to be supported and the required QoS (Quality of Service) leve