Omnet++ Research Papers

Band Codes (BC) have been recently proposed as a solution for controlled-complexity random Network Coding (NC) in mobile applications, where energy consumption is a major concern. In this paper, we investigate the potential of BC in a peer-to-peer video streaming scenario where malicious and honest nodes coexists. Malicious nodes launch the so called pollution attack by randomly modifying the content of the coded packets they forward to downstream nodes, preventing honest nodes from correctly recovering the video stream.

Whereas in much of the related literature this type of attack is addressed by identifying and isolating the malicious nodes, in this work we propose to address it by adaptively adjusting the coding scheme so to introduce resilience against pollution propagation. We experimentally show the impact of a pollution attack in a defenseless system and in a system where the coding parameters of BC are adaptively modulated following the discovery of polluted packets in the network. We observe that just by tuning the coding parameters, it is possible to reduce the impact of a pollution attack and restore the quality of the video communication.

Many applications, such as Intelligent Transport System (ITS), and mobile multimedia, use Internet-based Vehicular Ad Hoc Networks (IVANETs). In IVANETs, users often access multimedia content from anywhere using Internet connectivity to remote video streaming servers. Due to the high mobility of the nodes in IVANETS, however, maintaining Quality of Service (QoS) for these video streaming applications with respect to parameters such as jitter, throughput, buffering, and transmission delay is a challenging task. To address these challenges, we propose a new QoSaware Hierarchical Web Caching (QHWC) scheme in IVANETs.

We propose two new metrics, Load Utilization Ratio (LUR) and Query to Connectivity Ratio (QCR), to maintain the QoS for various video streaming applications in IVANETs. We compare the performance of our proposed QHWC scheme, with past approaches, such as Dynamic Service, Weighted Segment, and Machine Learning based using various parameters such as QCR, communication cost, query delay, Cache hit ratio, Query Generation Rate, Invalidation cost, and Cache update interval. Our results demonstrate that the proposed QHWC scheme yields an average decrease of 16.75 % and 22 % in communication Cost and Query Delay, respectively, and an average increase of 9.31 % in Cache Hit Ratio. Moreover, the Invalidation Cost reduces by 26.26 % (on average) with our proposed scheme compared to other schemes.

We present a novel system that optimizes the video delivery by mapping network conditions (QoS) to the QoE without penetrating video packets.

It takes the advantage of the Scalable Video Coding (SVC) that can organize video streams into different layers. Our approach helps to maximize the QoE with respect to capacity constraints.

This demonstration shows a new type of HTTP adaptive streaming (HAS) for mobile users. We will present an anticipatory HAS policy that adapts video quality based on a prediction of the wireless channel state. By anticipating a poor channel state and by reducing video quality in advance, this policy maximizes the number of seconds in the user’s play-out buffer before coverage is lost.

Even in difficult coverage situations such as tunnels and elevators, our approach reaches outstanding fluency without decreasing the average video bit-rate. With this anticipatory buffering technique users require no channel resources at low channel state, which increases spectral efficiency. Our solution is based on an modified player application and will be demonstrated on off-the-shelf Smartphones in a conventional 4G network.

This paper illustrates the implementation of a speech-to-speech translation humanoid robot in the domain of medical care. At this stage, the proposed system is a one-way translation that is designed to help English speaking patients describe their symptoms to Korean doctors or nurses. A humanoid robot is useful because it can be extended to reach out to people in need first and may substitute the role of human workers, unlike laptops or tablets.

The system consists of three main parts – speech recognition, English-Korean translation, and Korean speech generation. It utilizes CMU Sphinx-4 as a speech recognition tool. English-Korean translation in this system is based on the rule-based translation. The success rate of the translation shows reliable results from an experiment with a closed scenario.

With the potential to generate numerous connection requests, an explosive growth in the volume of data traffic and the number of mobile and machine-to-machine (M2M) devices has drawn new attention on the radio access network (RAN). Surging random access attempts cause not only severe preamble collisions but also down-link resource shortage, and thus degrade the performance of random access procedure. However, the effect of down-link resource shortage on system performance is not yet comprehensively studied.

In addition, most existing random access contention resolution mechanisms sacrifice RACH (random access channel) throughput for a high success probability, and thus the price is that low-throughput mechanisms need long time to deal with access attempts. In this work, we evaluate the MAC-level performance for the 4-step random access procedure in LTE systems, for both with and without constrained down-link resources. Further, we propose a novel RACH contention resolution scheme, the dynamic backoff (DB) scheme. DB can achieve high RACH throughput yielding a high random access success probability under various RACH overloaded scenarios.

IEEE 802.11ah task group is working on a new amendment of the IEEE 802.11 standard, suitable for high density WLAN networks in the sub 1 GHz band. It is expected to be the prevalent standard in many Internet of Things (IoT) and Machine to Machine (M2M) applications where it will support long-range and energy-efficient communication in dense network environments. Therefore, significant changes in the legacy 802.11 standards have been proposed to improve the network performance in high contention scenarios, most important of which is the Restricted Access Window (RAW) mechanism described in the amendment.

In this paper we analyze the performance of the RAW mechanism in the Non-Cross Slot Boundary case under various possible holding schemes. We propose new holding schemes as well as a new grouping scheme for RAW mechanism based on back-off states of the stations. The proposed schemes are shown to improve the saturation throughput and energy efficiency of the network through extensive simulations. These schemes can therefore be adapted in practical deployment scenarios of the IEEE 802.11ah use cases to improve the overall network performance. Overall, these advanced features make 802.11ah standard a true IoT-enabling technology towards seamless integration of massive amount of connected devices in the future.

Device-to-device (D2D) communication commonly refers to a type of technology that enable devices to communicate directly with each other without communication infrastructures such as access points (APs) or base stations (BSs). Bluetooth and WiFi-Direct are the two most popular D2D techniques, both working in the unlicensed industrial, scientific and medical (ISM) bands. Cellular networks, on the other hand, do not support direct over-the-air communications between users and devices.

However, with the emergence of context-aware applications and the accelerating growth of Machine-to-Machine (M2M) applications, D2D communication plays an increasingly important role. It facilitates the discovery of geographically close devices, and enables direct communications between these proximate devices, which improves communication capability and reduces communication delay and power consumption. To embrace the emerging market  that that requires D2D communications, mobile operators and vendors are accepting D2D as a part of the fourth generation (4G) Long Term Evolution (LTE)-Advanced standard in 3rd Generation Partnership Project (3GPP) Release 12.

We are witnessing an ever-increasing demand for cloud computing services, IoT, M2Mcommunications and advanced telecom applications. In addition, other applications like commerce, medical care, education, entertainment, as well as scientific meteorological simulations, genomics, computational physics, financial transactions and social network services generate a vast amount of data (Big Data). As a result it is estimated that digital data, which need to be processed and stored in data centres, will reach the zettabyte level before 2020. Time-sensitive Big data analysis and processing at high-performance computing infrastructures and by huge inter/intra data exchanges on data centres, becomes crucial and is a topic that attracts significant attention lately. The size of data-sets feasible to be processed in a reasonable amount of time is not only determined by the available processing capability but also by the bandwidth and the latency of the interconnecting network.

These new requirements, pose a serious challenge on the data-center and network operators who have to come up with a flexible and reliable solution, while considering the operational benefits that can result potentially for them. Novel photonic/plasmonic technologies as well as advanced optical networking approaches, may offer the capability of transmitting and processing of such big data with low power consumption, low latency and high level of flexibility, at relatively low costs. This tutorial discusses the impact of big data on the underlying network infrastructure with a particular focus on how novel photonic technologies and optical networking approaches in the high-performance computing (HPC), datacentre networks (DCN) and telecommunication networks can (TCN) be utilized to face the new requirements. The new infrastructure requirements in the big data era will be outlined. Then a brief presentation on the roadmap of new optical technologies that will be introduced in HPC, DCNs and TCNs in order – o improve their performance will be made. Finally in the third part of the tutorial, which will be the main focus, we will shift the discussion towards advanced networking solutions that enable flexibility, virtualization, application awareness and QoS support, thus making the network infrastructure more suitable for the new requirements.

This paper provides an overview of the Internet of Things (IoT) with emphasis on enabling technologies, protocols and application issues. The IoT is enabled by the latest developments in RFID, smart sensors, communication technologies and Internet protocols. The basic premise is to have smart sensors collaborate  directly without human involvement to deliver a new class of applications. The current revolution in Internet, mobile and machine-to-machine (M2M) technologies can be seen as the first phase of the IoT. In the coming years, the IoT is expected to bridge diverse technologies to enable new applications by connecting physical objects together in support of intelligent decision making. This paper starts by providing a horizontal overview of the IoT. Then, we give an overview of some technical details that pertain to the IoT enabling technologies, protocols and applications.

Compared to other survey papers in the field, our objective is to provide a more thorough summary of the most relevant protocols and application issues to enable researchers and application developers to get up to speed quickly on how the different protocols fit together to deliver desired functionalities without having to go through RFCs and the standards specifications. We also provide an overview of some of the key IoT challenges presented in the recent literature and provide a summary of related research work. Moreover, we explore the relation between the IoT and other emerging technologies including big data analytics and cloud and fog computing. We also present the need for better horizontal integration among IoT services. Finally, we present detailed service use-cases to illustrate how the different protocols presented in the paper fit together to deliver desired IoT services.