Koojana Kuladinithi

Technische Universität Hamburg | TUHH · Communication Networks

The growing number of space missions planned in the near future has created a need for a robust communication infrastructure. Such an infrastructure is being developed in the frame of lunar communications by ESA moonlight and NASA lunanet using Delay-and Disruption-Tolerant Networking (DTN) and Bundle Protocol (BP). While their characteristics have...

The emergence of the L-band Digital Aeronautical Communications System (LDACS) presents a significant opportunity for enabling Air-to-Air (A2A) communication to accommodate the growing number of aircraft. However, it requires overcoming significant Medium Access Control (MAC) delays and enhancing connectivity in sparse networks. Geographic greedy r...

In this chapter, we explore how the mobility of nodes influences the performance of opportunistic networks. First, we start with a general discussion of how scale and density are defined and how those impact the dissemination of data in opportunistic networks. Then, we dive deeper into how to gather realistic mobility data from real-world scenarios...

Security is of paramount importance in Opportunistic Networks (OppNets) due to its unique characteristics and operational challenges. OppNets are designed for environments with intermittent or disrupted connectivity such as disaster recovery. In such scenarios, traditional end-to-end communication models may not be feasible, making OppNets a crucia...

In this chapter, we discuss the challenges when comparing different opportunistic solutions (mostly forwarding protocols, but the discussion can be easily applied to any opportunistic services). We will look into what benchmarks are in general, which benchmarks exist for opportunistic networks, and how to use and interpret their results.

Data dissemination is the main research and implementation challenge in opportunistic networks. It addresses the question of how to forward data in a resource-efficient but also fast way. The main concept is called store-carry-forward, which means that nodes forward the data to other nodes, which carry it around until finding a better forwarder or...

This paper investigates the performance of a proposed IEEE 802.11 ad hoc-based wireless seismic data acquisition (WSDA) network architecture. The study centers on examining the network performance in the 2.4 and 5 GHz bands with focus on addressing WSDA challenges such as scalability, reliability, self-configuration and organization, interference e...

Infrastructure‐less networks connect communication devices end‐to‐end by managing links and routes independent of fixed networking facilities, relying on dedicated protocols running on end‐user devices. The large variety of infrastructure‐less concepts and related aspects can be confusing both for beginning Ph.D. students as well as experienced res...

Going wireless is one of the key industrial trends, which assists the emergence of new manufacturing and maintenance processes by reducing the complexity and cost of physical equipment. However, the adoption of Wireless Sensor Networks (WSNs) in production environments is limited due to the strict Quality of Service (QoS) requirements of industrial...

Seismic data acquisition in oil and gas exploration employs a large-scale network of geophone sensors deployed in thousands across a survey field. A central control unit acquires and processes measured data from geophones to come up with an image of the earth’s subterranean structure to locate oil and gas traps. Conventional seismic acquisition sys...

This paper aims to share the experiences during online teaching of two different project-based learning courses at Hamburg University of Technology (TUHH) during the COVID-19 (Corona) pandemic 2020. The success of project-based learning courses relies on how freely and openly students can discuss their task-oriented problems in small teams. The mos...

EPIC (Improving Employability Through Internationalization and Collaboration) is an Erasmus+ 3 year Strategic Partnership, which explores how blended learning can support multinational and interdisciplinary student projects. In this way it searches to combine the flexibility and cost-effectiveness of virtual collaboration with the benefits of physi...

Opportunistic networks have recently seen increasing interest in the networking community. They can serve a range of application scenarios, most of them being destination-less, i.e., without a-priori knowledge of who is the final destination of a message. In this paper, we explore the usage of data popularity for improving the efficiency of data fo...

At the Hamburg University of Technology, Germany, the modelling of communication networks using the OMNeT++ simulator and the INET framework is taught for Master students. Teaching the concepts of simulation and modelling while letting the students obtain a hands-on experience during a 14-week (4h/week) period (single semester) is a challenging tas...

This paper focuses on modeling the charateristics of opportunistic networks (OppNets). The motivation of this work is to develop a model which is closer to the reality to represent the data dissemination in OppNets. This paper shows our preliminary results validating our model in OppNets scenarios which give an opportunity to exchange data among a...

Simulation is one of the most powerful tools we have for evaluating the performance of Opportunistic Networks. In this survey, we focus on available tools and models, compare their performance and precision and experimentally show the scalability of different simulators. We also perform a gap analysis of state-of-the-art Opportunistic Network simul...

Opportunistic networks (OppNets) are focused to exploit direct, localised communications which occur in a peer-to-peer manner mostly based on people's movements and their contact durations. Therefore, the use of realistic mobility models is critical to evaluate the data dissemination in OppNets. One of the mobility models that is available in OMNeT...

Decentralised electric power generation using renewable energy sources are becoming increasingly popular. As a consequence, decentralised electrical energy sources such as photovoltaic (PV) are connected to the low voltage (LV) power grids. This raises the requirement of dedicated and coordinated control of loads and power generation to realize int...

All over the world, road congestion is among the most prevalent transport challenges usually in urban environments which not only increases fuel consumption and emission of harmful gases, but also causes stress for the drivers. Intelligent Transportation System (ITS) enables a better use of the infrastructure by connecting vehicles to other vehicle...

Testbeds play a crucial role in evaluating novel protocols, algorithms, and applications in controlled, but realistic environments. These testbeds are mainly used by researchers to realize diverse application environments, which are not realistic to be achieved in simulated environments (e.g., lossy channels in Wireless Sensor Networks (WSN)). Most...

The number of computing devices of the IoT are expected to grow exponentially. To address the communication needs of the IoT, research is being done to develop new networking architectures and to extend existing architectures. An area that lacks attention in these efforts is the emphasis on utilisation of omnipresent local data. There are a number...

We are in the process of developing a system architecture for opportunistic and information centric communications. This architecture (called Keetchi), meant for the Internet of Things (IoT) is focussed on enabling applications to perform distributed and decentralised communications among smart devices. To realise and evaluate this architecture, we...

This paper presents a preliminary system architecture of integrating OMNeT++ into the mosaik co-simulation framework. This will enable realistic simulation of communication network protocols and services for smart grid scenarios and on the other side, further development of communication protocols for smart grid applications. Thus, by integrating O...

Content Centric Networking (CCN) is a new paradigm in networking and a future Internet architecture. Performance evaluations show that conventional CCN forwarding strategies which use replication of Interests (standard) or the shortest path (best-face) do not perform well under high bandwidth requirements and loaded networks. We have designed and e...

The increasing interest and utilization of Wireless Sensor Networks has increased the requirements of energy saving for battery powered sensor nodes. Even in modern sensor nodes, communication causes the largest part of energy consumption and therefore ways to reduce the amount of data sending are widely concerned. One solution to reduce data trans...

Today, there exist several standards based and proprietary based protocols that can be used in Wireless Sensor Network (WSN) applications. Proprietary technologies are difficult to integrate into larger networks and currently available Internet-based services. The use of IP based technologies allows easy integration with existing network infrastruc...

The supervision of the environment of freight goods directly at the goods gives a better shelf-life estimation than monitoring at the inlet or outlet of the refrigeration unit. Implementing the monitoring spatially close to the good is typically more complex for the logistic service provider. Either this is done using wires or so-called data-logger...

Massively distributed clouds (MDC) have a huge potential in serving novel applications and services in many situations. Mainly, they are able to provide communication without the use of an infras- tructure and to guarantee full data and user anonymity. However, their implementation is not trivial and requires innovation in many different fields, su...

Several drafts in the CoRE WG are discussing the usage of CoAP on non-UDP/IP transports already. There are various use cases for non-UDP/IP transports. In order to structure the discussion, this draft introduces new terminology and transport scenarios.

The use of web services for sensor networking applications is seen as an important part in emerging M2M communications. The Constrained Application Protocol (CoAP) is proposed by the Internet Engineering Task Force (IETF) to optimize the use of the RESTful web service architecture for constrained nodes and networks, for example Wireless Sensor Netw...

The use of web services for sensor networking applications is seen as an important part in emerging M2M communications. The Constrained Application Protocol (CoAP) is proposed by the Internet Engineering Task Force (IETF) to optimize the use of the RESTful web service architecture for constrained nodes and networks, for example Wireless Sensor Netw...

The use of web services for sensor networking applications is seen as an important part in emerging M2M communications. The Constrained Application Protocol (CoAP) is proposed by the Internet Engineering Task Force (IETF) to optimize the use of the RESTful web service architecture for constrained nodes and networks, for example Wireless Sensor Netw...

In the Constrained RESTful Environments (CoRE) working group at the Internet Engineering Task Force (IETF) a Representational State Transfer (REST) architecture [1] is being defined for constrained nodes and networks, e.g. Wireless Sensor Networks (WSN). The CoRE working group has already proposed a standard called Constrained Application Protocol...

This chapter explores the question of how to implement opportunistic networks in practice. The main part of this question considers the connectivity technologies that support opportunistic communications. These can be organized into two types: general communication technologies and protocols and concrete software implementations and frameworks. Thi...

In this last technical chapter, we finally present concrete application scenarios for opportunistic networks. We have waited with this discussion until the end so that the properties, advantages, and limitations of opportunistic networks become clear in detail first. Even if many different application cases have been proposed in the literature, not...

When implementing opportunistic networks in real applications, not only connectivity problems need to be addressed, but also device restrictions. Each device (smartphones, sensor nodes, tablets) have its unique properties and resources. Some of them are critical for opportunistic communications and can make the difference between a well-functioning...

In this chapter, we detail how to use theoretical modeling in opportunistic networks (OppNets) using mathematical and computational methods to analyze their behavior. The models, though simplified representations of reality, help researchers predict network performance under different conditions and gain insights into network behavior. Particularly...

In this chapter, we address the evaluation of opportunistic networks in a general way. We introduce the three main approaches: real-world implementations, simulation, and analytical models. We compare them with each other from the perspective of their properties, such as their development and execution costs, repeatability and reproducibility, visi...

In this chapter, we introduce the different simulation models available and needed to simulate opportunistic networks in all their details. They include application (traffic) models, link abstraction models, mobility models, and contact traces. We discuss each of them individually, which concrete models exist, and how they work in general. Furtherm...

In this chapter, we start with an introduction to network simulators and especially to discrete event simulators. We explain how they work and what their most important properties are. We continue with several concrete simulators which can be used for evaluating opportunistic networks: OMNeT++, ONE, and ns-3. We discuss their pros and cons and comp...

The Trickle algorithm has proven to be of great benefit to the Wireless Sensor Networking area. It has shown general applicability in this field, e.g. for code distribution to smart objects and routing information distribution between smart objects. Up to now analysis of the algorithm has focussed on simulation studies and measurement campaigns. Th...

Seamless performance of communication applications is critical for today's mobile workers who are dependent on their mobile computing devices. One area of such criticality is the smoothness of handovers between Access Points (APs) in 802.11 based communications. In this work, two heuristic handover algorithms based on indoor positioning are designe...

The use of web services for sensor networking applications is seen as an important part in emerging M2M communi-cations. The Constrained Application Protocol (CoAP) is proposed by the IETF to optimize the use of the RESTful web service architecture in constrained nodes and networks, for example Wireless Sensor Networks. We present an IP based solut...

In wireless multi-hop ad hoc networks, the simultaneous use of multiple routes may degrade the performance of applications due to mutual interference of discovered paths, irrespective of whether paths are physically node disjoint or link disjoint. Therefore, the selection of noninterfering routes is the main criterion to be addressed when using mul...

Multipath routes in wireless multihop ad hoc networks have proven to increase performance compared to single path routing when providing backup paths in case of path failures and also distributing flows (i.e. data traffic) among several paths. The drawback of using multipath simultaneously in wireless multihop ad hoc networks is that the other node...

Method for implementing a parallel network attachment functionality to at least two mobile access networks; the home subscriber entity (HSS) transfers data to the attachment decision entity (ISADF), the data concerning the authorisation and the control of the parallel network attachment of the user device (UE); and in case that a parallel network a...

An ad-hoc network is a network whose particular characteristics include absence of any kind of infrastructure, dynamic topology and limited resources. Up to day, several routing protocols have been proposed to face such a hostile environment. These solutions usually provide to the sources of data flows with single valid paths towards their destinat...

An evolving wireless world is constantly providing users with a wider set of access technologies to choose from, each with different capabilities and properties. In this world, IMS as defined by 3GPP provides an enabling, standardized multimedia architecture that is access independent, hence, providing service convergence. This trend is accompanied...

Information and Communication Technology includes many dif-ferent concepts, implementations and usages of Self-Organization (Serugendo et al. 2004; Czap et al. 2005; Brueckner et al. 2005). These are among others: ad hoc routing, autonomic communication, Self-Star and peer-to-peer networks. The constituting features of autonomous control, as alread...

Ad hoc networks are considered to provide flexible and robust communication in emergency scenarios like fire fighting. However, for the time being, it is not clear how existing digital wireless communication technologies perform in environments with fire, smoke and vapour. To investigate this issue, we carried out several experiments at the trainin...

An attractive application scenario for wearable computing is the maintenance of airplanes. In this scenario, wearable computers need wireless communication with high data rates to enable mobile workers to communicate with remote assistants or to obtain video manuals from remote servers. This paper describes experiments and results of measurements w...

Link: http://www.sfb637.uni-bremen.de/pubdb/repository/SFB637-B3-05-003-IC.pdf

The Ad hoc On-Demand Distance Vector (AODV) routing protocol is designed for use in mobile ad-hoc networks. As of the writing of this article, there exist several implementations of the AODV protocol for a range of operating systems (e.g., Unix/Linux, Windows), different devices (e.g. Notebook computers, PDAs) each developed using different techniq...

Internet capable mobile or portable devices are already a modern commodity while it is becoming all the more common that such devices are hosts to more than one wireless interface. The aim of this paper is to show that a mobile user may make best use of this property by using multiple wireless interfaces simultaneously. This would incline that the...

Information is one of the key ingredients in the success of any industry. Having information and sending information at the right time and at the right place makes this success. Wearable computing and wireless communication technologies have brought up an informational environment that can be character- ized as anytime-anywhere, which is able to en...

There are currently, many bearer technologies available (Wireline, WLAN, GSM, GPRS, UMTS, etc.) that modern communication devices can use to connect to the Internet. Mobile IP enables such devices to use any of these bearer technologies even while roaming between them and without breaking ongoing communications. However, Mobile IP does not provide...

This paper initially, describes the NOMAD test-bed be- ing set up at ComNets for network integration to integrate various bearer technologies (GSM, GPRS, WLAN, Ethernet). It is based on different Mobile IP versions (IPv4 and IPv6) and software for ad-hoc networking using the AODV (Ad-hoc On Demand Vector routing) protocol. The second section descri...

A key area of consideration in self organizing ad hoc networks is the routing mechanisms. The On-Demand mechanism in IP based networks has become popular due to the lower overheads required in managing routes which make it ideal for even smaller, resource restrained mobile computing devices. This publication looks at the implementation aspects of d...

Wearable computing along with advanced mobile communication has the potential to revolutionise the working environment and working processes of the mobile worker of the AEC industry. While wearable computing allows the mobile worker to execute his/her work and tasks more efficiently and safer with the support of information provided by novel user i...