Application acceleration for wireless and mobile data networks

This work studies application acceleration for wireless and mobile data networks. The problem of accelerating application can be addressed along multiple dimensions. The first dimension is advanced network protocol design, i.e., optimizing underlying network protocols, particulary transport layer protocol and link layer protocol. Despite advanced network protocol design, in this work we observe that certain application behaviors can fundamentally limit the performance achievable when operating over wireless and mobile data networks. The performance difference is caused by the complex application behaviors of these non-FTP applications. Explicitly dealing with application behaviors can improve application performance for new environments. Along this overcoming application behavior dimension, we accelerate applications by studying specific types of applications including Client-server, Peer-to-peer and Location-based applications. In exploring along this dimension, we identify a set of application behaviors that significantly affect application performance. To accommodate these application behaviors, we firstly extract general design principles that can apply to any applications whenever possible. These design principles can also be integrated into new application designs. We also consider specific applications by applying these design principles and build prototypes to demonstrate the effectiveness of the solutions. In the context of application acceleration, even though all the challenges belong to the two aforementioned dimensions of advanced network protocol design and overcoming application behavior are addressed, application performance can still be limited by the underlying network capability, particularly physical bandwidth. In this work, we study the possibility of speeding up data delivery by eliminating traffic redundancy present in application traffics. Specifically, we first study the traffic redundancy along multiple dimensions using traces obtained from multiple real wireless network deployments. Based on the insights obtained from the analysis, we propose Wireless Memory (WM), a two-ended AP-client solution to effectively exploit traffic redundancy in wireless and mobile environments. Application acceleration can be achieved along two other dimensions: network provision ing and quality of service (QoS). Network provisioning allocates network resources such as physical bandwidth or wireless spectrum, while QoS provides different priority to different applications, users, or data flows. These two dimensions have their respective limitations in the context of application acceleration. In this work, we focus on the two dimensions of overcoming application behavior and Eliminating traffic redundancy to improve application performance. The contribution of this work is as follows. First, we study the problem of application acceleration for wireless and mobile data networks, and we characterize the dimensions along which to address the problem. Second, we identify that application behaviors can significantly affect application performance, and we propose a set of design principles to deal with the behaviors. We also build prototypes to conduct system research. Third, we consider traffic redundancy elimination and propose a wireless memory approach.Ph.D.Committee Chair: Sivakumar, Raghupathy; Committee Member: Ammar, Mostafa; Committee Member: Fekri, Faramarz; Committee Member: Ji, Chuanyi; Committee Member: Ramachandran, Umakishor

Wireless sensor networks in motion : clustering algorithms for service discovery and provisioning

The evolution of computer technology follows a trajectory of miniaturization\ud and diversification. The technology has developed from mainframes (large computers used by many people) to personal computers (one computer per person)\ud and recently, embedded computers (many computers per person). One of the\ud smallest embedded computers is a wireless sensor node, which is a batterypowered\ud miniaturized device equipped with processing capabilities, memory,\ud wireless communication and sensors that can sense the physical parameters of\ud the environment. A collection of sensor nodes that communicate through the\ud wireless interface form a Wireless Sensor Network (WSN), which is an ad-hoc,\ud self organizing network that can function unattended for long periods of time.\ud Although traditionally WSNs have been regarded as static sensor arrays\ud used mainly for environmental monitoring, recently, WSN applications have\ud undergone a paradigm shift from static to more dynamic environments, where\ud nodes are attached to moving objects, people or animals. Applications that\ud use WSNs in motion are broad, ranging from transport and logistics to animal\ud monitoring, health care and military, just to mention a few.\ud These application domains have a number of characteristics that challenge\ud the algorithmic design of WSNs. Firstly, mobility has a negative effect on\ud the quality of the wireless communication and the performance of networking\ud protocols. Nevertheless, it has been shown that mobility can enhance the functionality of the network by exploiting the movement patterns of mobile objects. Secondly, the heterogeneity of devices in a WSN has to be taken into account for increasing the network performance and lifetime. Thirdly, the WSN services should ideally assist the user in an unobtrusive and transparent way. Fourthly, energy-efficiency and scalability are of primary importance to prevent the network performance degradation. This thesis focuses on the problems and enhancements brought in by networ mobility, while also accounting for heterogeneity, transparency, energy efficiency and scalability. We propose a set of algorithms that enable WSNs to self-organize efficiently in the presence of mobility, adapt to and even exploit dynamics to increase the functionality of the network. Our contributions include an algorithm for motion detection, a set of clustering algorithms that can be used to handle mobility efficiently, and a service discovery protocol that enables dynamic user access to the WSN functionality

InnoCube - Preparing the Fully Wireless Satellite Data Bus for Launch

The Innovative CubeSat for Education (InnoCube) mission is a technology demonstrator cubesat mission relying on a fully wireless data-bus, set to launch in November 2024. This paper will discuss the mission objectives, design and implementation of the InnoCube mission with an emphasis on the wireless data bus. The mission is a collaborative project between the University of Wuerzburg and the Technische Universität Berlin in Germany. The mission objectives are to showcase the viability of a fully wireless data-bus for intra-satellite communication onboard cubesats and satellites in general, to provide a platform for testing and validating these new technologies, and to provide an opportunity for students to gain hands-on experience in the design and operation of a cubesat mission. The design of the InnoCube mission includes a 3U cubesat bus including the avionics, the wireless data-bus, and a suite of payloads provided by the TU Berlin. The wireless data bus is based on a time-division multiple access protocol and will enable the cubesat’s subsystems to communicate within the satellite, relying only on wireless means of communication. InnoCube will provide valuable insights and data concerning the feasibility of a wireless data bus for space applications, which can be especially beneficial to larger satellites and their associated large data harness. The mission will be operated from the Technische Universität Berlin and will be launched in 2024. Firstly, the paper will give an overview of the design of the satellite’s subsystems including the additional payloads. Then, the technology used in the wireless bus will be described. Special emphasis will be given to the integration and testing of the wireless bus before launch. This paper will also discuss the challenges associated with the InnoCube mission, such as the need for robust communication protocols, the need for reliable power sources, and the need for reliable redundancy control schemes. Additionally, the paper will discuss the potential applications of the technology demonstrated by the InnoCube mission along with their advantages and disadvantages compared to a traditional data harness. Finally, the paper will discuss the potential benefits and open topics for future missions using wireless technology for intra-satellite communication as demonstrated by the InnoCube mission

Topology Control, Routing Protocols and Performance Evaluation for Mobile Wireless Ad Hoc Networks

A mobile ad-hoc network (MANET) is a collection of wireless mobile nodes forming a temporary network without the support of any established infrastructure or centralized administration. There are many potential applications based the techniques of MANETs, such as disaster rescue, personal area networking, wireless conference, military applications, etc. MANETs face a number of challenges for designing a scalable routing protocol due to their natural characteristics. Guaranteeing delivery and the capability to handle dynamic connectivity are the most important issues for routing protocols in MANETs. In this dissertation, we will propose four algorithms that address different aspects of routing problems in MANETs. Firstly, in position based routing protocols to design a scalable location management scheme is inherently difficult. Enhanced Scalable Location management Service (EnSLS) is proposed to improve the scalability of existing location management services, and a mathematical model is proposed to compare the performance of the classical location service, GLS, and our protocol, EnSLS. The analytical model shows that EnSLS has better scalability compared with that of GLS. Secondly, virtual backbone routing can reduce communication overhead and speedup the routing process compared with many existing on-demand routing protocols for routing detection. In many studies, Minimum Connected Dominating Set (MCDS) is used to approximate virtual backbones in a unit-disk graph. However finding a MCDS is an NP-hard problem. In the dissertation, we develop two new pure localized protocols for calculating the CDS. One emphasizes forming a small size initial near-optimal CDS via marking process, and the other uses an iterative synchronized method to avoid illegal simultaneously removal of dominating nodes. Our new protocols largely reduce the number of nodes in CDS compared with existing methods. We show the efficiency of our approach through both theoretical analysis and simulation experiments. Finally, using multiple redundant paths for routing is a promising solution. However, selecting an optimal path set is an NP hard problem. We propose the Genetic Fuzzy Multi-path Routing Protocol (GFMRP), which is a multi-path routing protocol based on fuzzy set theory and evolutionary computing

Energy-efficient wireless communication

In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters