Myspeedtest: active and passive measurements of cellular data networks

As the number and diversity of applications available to mobile users increases, there is an increasing need for developers, network service providers, and users to understand how users perceive the network performance of these applications. MySpeedTest is a measurement tool that actively probes the network to determine not only TCP throughput and round trip time, but also the proximity to popular content providers, IP packet delay variation, and loss. It also records other metadata that could affect user experience, such as signal strength, service provider, connection type, battery state, device type, manufacturer, time of day, and location. The tool also takes passive measurements of the applications installed on the device and the network usage of these applications. My SpeedTest is available on the Google Play Store and currently has 1300+ active users. This thesis presents the design and implementation of MySpeedTest as well as effect of metrics like latency and IP packet delay variation on performance.MSCommittee Chair: Nick Feamster; Committee Member: Patrick Traynor; Committee Member: Raghupathy Sivakuma

Mobile network performance from user devices: A longitudinal, multidimensional analysis

Abstract. In the cellular environment, operators, researchers and end users have poor visibility into network performance for devices. Improving visibility is challenging because this performance depends factors that include carrier, access technology, signal strength, geographic location and time. Addressing this requires longitudinal, continuous and large-scale measurements from a diverse set of mobile devices and networks. This paper takes a first look at cellular network performance from this perspective, using 17 months of data collected from devices located throughout the world. We show that (i) there is significant variance in key performance metrics both within and across carriers; (ii) this variance is at best only partially explained by regional and time-of-day patterns; (iii) the stability of network performance varies substantially among carriers. Further, we use the dataset to diagnose the causes behind observed performance problems and identify additional measurements that will improve our ability to reason about mobile network behavior

Research Resources for Network Application Studies

The growth of computer networks has led to increasing diversity of Internet applications, including streaming media and network games. However, without precise information on how network and system improvements benefit the networked application user, it is difficult to properly assess the benefits of new network treatments or to design the next generation networks that will effectively support the QoS of emerging applications. This research attempts to bridge this gap in understanding with three innovative projects: 1) integrating measures of network performance with user perception; 2) quality of service for network games; and 3) perceived quality of adaptive streaming media repair. With the requested research resources, we have developed an application performance studies laboratory that allows us to finely control network performance for a range of selected networked applications. Each project shares research resources in the new laboratory to measure performance for interactive applications, network games and streaming media repair, as appropriate

Spectrum Policy and Management

This project provides an examination of the FCC’s policies towards spectrum reallocation. The project examines the National Broadband Plan and how the FCC has approached the goals described within it. The demand for broadband communications has increased dramatically in recent years and has resulted in a predicted spectrum deficit in the near future. In addition to a number of spectrum auctions and their winners the project examines how the redistribution of spectrum impacts the broadband community. The project also provides an examination of spectrum reallocation and policy in other countries, to provide a broader view of spectrum policy. Finally the project examines new spectrum technologies and spectrum usage policies to further examine how the US’s spectrum policies should evolve

Application of cognitive radio based sensor network in smart grids for efficient, holistic monitoring and control.

Doctoral Degree. University of KwaZulu-Natal, Durban.This thesis is directed towards the application of cognitive radio based sensor network (CRSN) in smart grid (SG) for efficient, holistic monitoring and control. The work involves enabling of sensor network and wireless communication devices for spectra utilization via the capability of Dynamic Spectrum Access (DSA) of a cognitive radio (CR) as well as end to end communication access technology for unified monitoring and control in smart grids. Smart Grid (SG) is a new power grid paradigm that can provide predictive information and recommendations to utilities, including their suppliers, and their customers on how best to manage power delivery and consumption. SG can greatly reduce air pollution from our surrounding by renewable power sources such as wind energy, solar plants and huge hydro stations. SG also reduces electricity blackouts and surges. Communication network is the foundation for modern SG. Implementing an improved communication solution will help in addressing the problems of the existing SG. Hence, this study proposed and implemented improved CRSN model which will help to ultimately evade the inherent problems of communication network in the SG such as: energy inefficiency, interference, spectrum inefficiencies, poor quality of service (QoS), latency and throughput. To overcome these problems, the existing approach which is more predominant is the use of wireless sensor network (WSNs) for communication needs in SG. However, WSNs have low battery power, low computational complexity, low bandwidth support, and high latency or delay due to multihop transmission in existing WSN topology. Consequently, solving these problems by addressing energy efficiency, bandwidth or throughput, and latency have not been fully realized due to the limitations in the WSN and the existing network topology. Therefore, existing approach has not fully addressed the communication needs in SG. SG can be fully realized by integrating communication network technologies infrastructures into the power grid. Cognitive Radio-based Sensor Network (CRSN) is considered a feasible solution to enhance various aspects of the electric power grid such as communication with end and remote devices in real-time manner for efficient monitoring and to realize maximum benefits of a smart grid system. CRSN in SG is aimed at addressing the problem of spectrum inefficiency and interference which wireless sensor network (WSN) could not. However, numerous challenges for CRSNs are due to the harsh environmental wireless condition in a smart grid system. As a result, latency, throughput and reliability become critical issues. To overcome these challenges, lots of approaches can be adopted ranging from integration of CRSNs into SGs; proper implementation design model for SG; reliable communication access devices for SG; key immunity requirements for communication infrastructure in SG; up to communication network protocol optimization and so on. To this end, this study utilized the National Institute of Standard (NIST) framework for SG interoperability in the design of unified communication network architecture including implementation model for guaranteed quality of service (QoS) of smart grid applications. This involves virtualized network in form of multi-homing comprising low power wide area network (LPWAN) devices such as LTE CAT1/LTE-M, and TV white space band device (TVBD). Simulation and analysis show that the performance of the developed modules architecture outperforms the legacy wireless systems in terms of latency, blocking probability, and throughput in SG harsh environmental condition. In addition, the problem of multi correlation fading channels due to multi antenna channels of the sensor nodes in CRSN based SG has been addressed by the performance analysis of a moment generating function (MGF) based M-QAM error probability over Nakagami-q dual correlated fading channels with maximum ratio combiner (MRC) receiver technique which includes derivation and novel algorithmic approach. The results of the MATLAB simulation are provided as a guide for sensor node deployment in order to avoid the problem of multi correlation in CRSN based SGs. SGs application requires reliable and efficient communication with low latency in timely manner as well as adequate topology of sensor nodes deployment for guaranteed QoS. Another important requirement is the need for an optimized protocol/algorithms for energy efficiency and cross layer spectrum aware made possible for opportunistic spectrum access in the CRSN nodes. Consequently, an optimized cross layer interaction of the physical and MAC layer protocols using various novel algorithms and techniques was developed. This includes a novel energy efficient distributed heterogeneous clustered spectrum aware (EDHC- SA) multichannel sensing signal model with novel algorithm called Equilateral triangulation algorithm for guaranteed network connectivity in CRSN based SG. The simulation results further obtained confirm that EDHC-SA CRSN model outperforms conventional ZigBee WSN in terms of bit error rate (BER), end-to-end delay (latency) and energy consumption. This no doubt validates the suitability of the developed model in SG

Redes sem fio de longas distâncias: novas contribuições para a justiça em nível de usuário e para a qualidade de serviços em fluxos de vídeo escalável

Esta tese tem como objetivo a avaliação de desempenho do acesso sem fio à internet para o uso de aplicações web e de vídeo escalável. O texto trata das principais contribuições alcançadas por este trabalho que são: (i) o desenvolvimento de um novo modelo de simulação de uma célula EVDO com o qual avaliamos justiça usando métricas como a vazão e o atraso, sob influência de diferentes cenários de mobilidade. Além disso, propomos uma solução simples para melhorar a justiça entre os usuários deste tipo de rede sem fio; e, (ii) a proposta de modelos matemáticos que nos permitem estudar, sob um novo ponto de vista, o processo aleatório de perda em filas FIFO/Droptail. Com base os resultados obtidos, propomos uma nova técnica fim-a-fim de transmissão de fluxos de vídeo escalável. Mostramos com essa técnica que, mesmo sem o emprego de complexos algoritmos de escalonamento e descarte nos roteadores, é possível priorizar os pacotes mais importantes para a qualidade do vídeo sem o uso de métodos tradicionais de priorização. Através de modelos de simulação desenvolvidos durante esta tese, avaliamos o ganho de qualidade atingido quando nossa técnica é usada, considerando perfis de vídeos bem conhecidos

Economically sustainable public security and emergency network exploiting a broadband communications satellite

The research contributes to work in Rapid Deployment of a National Public Security and Emergency Communications Network using Communication Satellite Broadband. Although studies in Public Security Communication networks have examined the use of communications satellite as an integral part of the Communication Infrastructure, there has not been an in-depth design analysis of an optimized regional broadband-based communication satellite in relation to the envisaged service coverage area, with little or no terrestrial last-mile telecommunications infrastructure for delivery of satellite solutions, applications and services. As such, the research provides a case study of a Nigerian Public Safety Security Communications Pilot project deployed in regions of the African continent with inadequate terrestrial last mile infrastructure and thus requiring a robust regional Communications Satellite complemented with variants of terrestrial wireless technologies to bridge the digital hiatus as a short and medium term measure apart from other strategic needs. The research not only addresses the pivotal role of a secured integrated communications Public safety network for security agencies and emergency service organizations with its potential to foster efficient information symmetry amongst their operations including during emergency and crisis management in a timely manner but demonstrates a working model of how analogue spectrum meant for Push-to-Talk (PTT) services can be re-farmed and digitalized as a “dedicated” broadband-based public communications system. The network’s sustainability can be secured by using excess capacity for the strategic commercial telecommunication needs of the state and its citizens. Utilization of scarce spectrum has been deployed for Nigeria’s Cashless policy pilot project for financial and digital inclusion. This effectively drives the universal access goals, without exclusivity, in a continent, which still remains the least wired in the world

Prototype Of Coupling Unit Network For Power Line Communications

Power Line Communications has made impressive strides since its introduction. Power Line Communications (PLC) or Broadband over Power Lines (BPL) is the method of transmitting broadband signals over the power lines and making it available at the power outlet in homes. It provides last mile communication and makes use of existing power lines to transmit signals, thereby eliminating the need to lay cables all over again. PLC is fast becoming a commercial reality in the United States. The Federal Communications Commission (FCC) is working toward making PLC a standard with particular emphasis on power emission issues and interference with nearby bands. Power companies, vendors and ISPs (Internet Service Providers) have tied up to bring this new technology to market. The Power line environment is inherently unpredictable due to interference, low signaling impedance and the highly linear operating environment that PLC transmitters require. The coupling unit in the PLC system acts as a filter and eliminates the harmful AC signal from interfering with the broadband signals. A coupling unit amplifier topology that provides gain equalization and wideband mitigation to the effects of low-impedance loads on PLC in the high frequency range has been explored in detail in this study. The amplifier is verified for its performance by means of circuit simulation using industry-standard software such as Agilent\u27s Advanced Design System (ADS). The coupling unit has also been fabricated to verify the performance. An experimental setup for verifying the performance of the coupling unit using a PLC transmitter and PLC receiver has also been proposed