Andreas Timm-Giel

LTE wireless virtualization and spectrum management

Many research initiatives have started looking into Future Internet solutions in order to satisfy the ever increasing requirements on the Internet and also to cope with the challenges existing in the current one. Some are proposing further enhancements while others are proposing completely new approaches. Network Virtualization is one solution that is able to combine these approaches and therefore, could play a central role in the Future Internet. It will enable the existence of multiple virtual networks on a common infrastructure even with different network architectures. Network Virtualization means setting up a network composed of individual virtualized network components, such as nodes, links, and routers. Mobility will remain a major requirement, which means that also wireless resources need to be virtualized. In this paper the Long Term Evolution (LTE) was chosen as a case study to extend Network Virtualization into the wireless area.

LTE mobile network virtualization

Network virtualization is receiving immense attention in the research community all over the world. There is no doubt that it will play a significant role in shaping the way we do networking in the future. There have been different approaches to virtualize different aspects of the network: some are focusing on resource virtualization like node, server and router virtualization; while others are focusing on building a framework to set up virtual networks on the fly based on different virtual resources. Nevertheless, one very important piece of the puzzle is still missing, that is “Wireless Virtualization”. The virtualization of the wireless medium has not yet received the appropriate attention it is entitled to, and there have only been some early attempts in this field. In this paper a general framework for virtualizing the wireless medium is proposed and investigated. This framework focuses on virtualizing mobile communication systems so that multiple operators can share the same physical resources while being able to stay isolated from each other. We mainly focus on the Long Term Evolution (LTE) but the framework can also be generalized to fit any other wireless system. The goal of the paper is to exploit the advantages that can be obtained from virtualizing the LTE system, more specifically virtualizing the air interface (i.e. spectrum sharing). Two different possible gain areas are explored: spectrum multiplexing and multi-user diversity.

Multi-QoS-Aware Fair Scheduling for LTE

the MAC scheduler is an important and crucial entity of the Long Term Evolution (LTE) and is responsible for efficiently allocating the radio resources among mobile users who have different QoS demands. The scheduler takes different considerations into account such as throughput and fairness when deciding the allocation of the scarce radio resources. LTE is an all IP packet system in which guaranteeing QoS is a real challenge. Therefore the LTE MAC scheduler should consider not only the throughput optimization but also the QoS differentiations in an effective manner. In this paper, we propose a novel LTE downlink MAC scheduling algorithm. The proposed scheduler differentiates between the different QoS classes and their requirements. Two different QoS classifications are considered: Guaranteed Bit Rate (GBR) and non Guaranteed Bit Rate (non-GBR). The proposed scheduler also considers the different users channel conditions and tries to create a balance between the QoS guarantees and the multi-user diversity in a proportional fair manner. The simulation analysis confirms that guaranteeing the different QoS requirements is possible.

WearIT@work: Toward Real-World Industrial Wearable Computing

Wearable computers are often cited as an enabling technology for out-of-office applications. In fact, there has been a considerable amount of work on industrial applications of wearables. However, with the notable exception of the symbol arm-worn system, this research has had little impact on industrial practice. The wearIT@work project is a 4 1/2-year effort financed by the European Union and aimed at facilitating real-life industrial deployment of wearable technology. The project is at the end of its third year. With 42 partners and a project funding of 23.7 million Euro (half of which comes from the EU), this consortium is the largest civilian wearable-computing effort worldwide. We are organizing the project around four pilot applications - aircraft maintenance, car production, healthcare, and emergency response - that drive the work in a bottom-up, user-centered approach.

Optimal Virtual Network Embedding: Node-Link Formulation

Network Virtualization is claimed to be a key component of the Future Internet, providing the dynamic support of different networks with different paradigms and mechanisms in the same physical infrastructure. A major challenge in the dynamic provision of virtual networks is the efficient embedding of virtual resources into physical ones. Since this problem is known to be NP-hard, previous research focused on designing heuristic-based algorithms; most of them either do not consider a simultaneous embedding of virtual nodes and virtual links, or apply link-path formulation, leading to non-optimal solutions. This paper proposes an integer linear programming (ILP) formulation to solve the online virtual network embedding problem as a result of an objective function striving for the minimization of resource consumption and load balancing. To this end 3 different objective functions are proposed and evaluated. This approach applies multi-commodity flow constraint to accomplish a node-link formulation that optimizes the allocation of physical network resources. This proposal is evaluated against state of the art heuristics. The performance of the heuristics related to Virtual Network (VN) request acceptance ratio is, at least, 30% below the one of the Virtual Network Embedding Node-Link Formulation (VNE-NLF) method. From the three cost functions evaluated, the Weighted Shortest Distance Path (WSDP) is the one which embeds more VNs and also requires, on average, less physical resources per embedding.

Environmental monitoring aware routing: making environmental sensor networks more robust

Wireless Sensor Networks (WSNs) have a broad application range in the area of monitoring and surveillance tasks. Among these tasks, disaster detection or prevention in environmental scenarios is one typical application for WSN. Disasters may for example be forest fires, volcano outbreaks or flood disasters. Here, the monitored events have the potential to destroy the sensor devices themselves. This has implications for the network lifetime, performance and robustness. While a fairly large body of work addressing routing in WSNs exists, little attention has been paid to the aspect of node failures caused by the sensed phenomena themselves. This paper presents a proactive routing method that is aware of the node’s destruction threat and adapts the routes accordingly, before node failure results in broken routes, delay and power consuming route re-discovery. The performance of the presented routing scheme is evaluated and compared to OLSR based routing in the same scenario.

A Novel LTE Wireless Virtualization Framework

Network virtualization is one of the topics that recently have been receiving attention in the research community. It is becoming evidently clear that network virtualization will be a major player in the shaping of the Future Internet. Many research projects around the world are studying different aspects of network virtualization: some are focusing on resource virtualization like Node, Server and Router virtualization; while others are focusing on building a framework to setup virtual networks on the fly based on the different virtual resources. In spite of all that work, we still think that one very important piece of the puzzle is still missing that is “Wireless Virtualization”. According to the best of our knowledge, the virtualization of the wireless medium has not yet received the appropriate attention it is entitled to, and there has been very small work done in that field. This is why this paper is proposing a framework for the virtualization of the wireless medium. This framework is proposed to virtualize mobile communication systems so that multiple operators can share the same physical resources. We mainly focus on the Long Term Evolution (LTE) but the framework can also be generalized to fit any other wireless system.

Investigation of Network Virtualization and Load Balancing Techniques in LTE Networks

Mobile Network Virtualization (NV) is an emerging technique which has drawn increasingly research attention. Network Virtualization enables multiple network operators to share a common infrastructure (including core network, transport network and access network) so as to reduce the investment capital while improving the overall performance at the same time. This is achieved by exploring the multiplexing gain. Similarly, Load Balancing (LB) is a well-known mechanism used in mobile networks to offload excessive traffic from high-load cells (hot spots) to low-load ones within one network operator. This paper aims at investigating the potential gain of applying NV in LTE (Long Term Evolution) networks and compares it with the LB scheme gain. In this paper, we propose an LTE virtualization framework (that enables spectrum sharing) and a dynamic load balancing scheme for multi-eNB and multi-VO (Virtual Operator) systems. We compare the performance gain of both schemes for different applications, e.g. VoIP, video, HTTP and FTP. We also investigate the parameterization of both schemes, e.g. sharing intervals, LB intervals and safety margins, in order to find the optimal parameter settings. The presented results show that the LTE networks can benefit from both NV and LB techniques.

Mobile M2M communication architectures, upcoming challenges, applications, and future directions

Machine-to-machine (M2M) communication is becoming an increasingly important part of mobile traffic and thus also a topic of major interest for mobile communication research and telecommunication standardization bodies. M2M communication offers various ubiquitous services and is one of the main enablers of the vision inspired by the Internet of Things (IoT). The concept of mobile M2M communication has emerged due to the wide range, coverage provisioning, high reliability, and decreasing costs of future mobile networks. Nevertheless, M2M communications pose significant challenges to mobile networks, e.g., due to the expected large number of devices with simultaneous access for sending small-sized data, and a diverse application range. This paper provides a detailed survey of M2M communications in the context of mobile networks, and thus focuses on the latest Long-Term Evolution-Advanced (LTE-A) networks. Moreover, the end-to-end network architectures and reference models for M2M communication are presented. Furthermore, a comprehensive survey is given to M2M service requirements, major current standardization efforts, and upcoming M2M-related challenges. In addition, an overview of upcoming M2M services expected in 5G networks is presented. In the end, various mobile M2M applications are discussed followed by open research questions and directions.

Virtual lifeline: Multimodal sensor data fusion for robust navigation in unknown environments

We present a novel, multimodal indoor navigation technique that combines pedestrian dead reckoning (PDR) with relative position information from wireless sensor nodes. It is motivated by emergency response scenarios where no fixed or pre-deployed global positioning infrastructure is available and where typical motion patterns defeat standard PDR systems. We use RF and ultrasound beacons to periodically re-align the PDR system and reduce the impact of incremental error accumulation. Unlike previous work on multimodal positioning, we allow the beacons to be dynamically deployed (dropped by the user) at previously unknown locations. A key contribution of this paper is to show that despite the fact that the beacon locations are not known (in terms of absolute coordinates), they significantly improve the performance of the system. This effect is especially relevant when a user re-traces (parts of) the path he or she had previously travelled or lingers and moves around in an irregular pattern at single locations for extended periods of time. Both situations are common and relevant for emergency response scenarios. We describe the system architecture, the fusion algorithms and provide an in depth evaluation in a large scale, realistic experiment.