Carmelita Goerg

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.

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.

Performance Evaluation of CoAP Using RPL and LPL in TinyOS

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 Networks (WSN). In this paper, we present a performance evaluation of the CoAP protocol implemented for the embedded operating system TinyOS. The CoapBlip implementation has been deployed on 20 TelosB motes forming a multi- hop network using the Routing Protocol for Low- power and Lossy Networks (RPL) with the two objective function of MRHOF and OF0. The performance of CoAP has been studied using both objective functions in the routing layer together with having LPL (Low Power Listening) enabled or disabled.

Game-Theory Based User Centric Network Selection with Media Independent Handover Services and Flow Management

Future envisions universal and uninterrupted access to information owing to the widespread use of heterogeneous wireless technologies. The integration of heterogeneous wireless technologies and existence of multi-mode terminals enable users get associated to the best available networks according to user preferences over different application specific requirements, prices and network technologies. In this paper we present the user-centric network selection decision mechanism, where negotiation between users and network operators is carried out using game-theoretic approach. We model the utility functions of users and network operators in terms of offered prices and service quality. The proposed approach builds on IEEE 802.21standard. Session Initiation Protocol(SIP) and Mobile Internet Protocol (MIPv6) based flow management solutions are given, the later approach is implemented using OPNET modeller simulator. The performance of our approachis compared with Long-term contractual approach in termsof users throughput, users’ cost, operators’ revenue and call blocking probability.

Performance comparison of scheduling algorithms for multipath transfer

Multipath transport protocols such as Multipath TCP can concurrently use several subflows to transmit a TCP flow over potentially different paths. Since more than one subflow is used, an efficient multipath scheduling algorithm is needed at the sender. The objective of the scheduler is to identify the subflow over which the current data packet should be sent. This paper compares the most important types of schedulers for multipath transfers. We model their performance analytically and derive key metrics, most notably the resulting end-to-end delay over heterogeneous paths. Our results show that a scheduler minimizing the packet delivery delay yields the best overall performance, but it is complex to realize. An alternative scheduler based on the sender queue size is simpler and has sufficient performance for relatively small asymmetry between the multiple paths. Our model results are confirmed by measurements with a real multipath transport protocol.

An On-demand Multi-Path Interest Forwarding strategy for content retrievals in CCN

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 evaluated the performance of an On-demand Multi-Path Interest Forwarding (OMP-IF) strategy which identifies a set of paths based on the disjointness of paths to content locations. Then, the discovered paths are used simultaneously to distribute (split) Interests based on the characteristics of the paths. We have evaluated OMP-IF strategy using a simulator with a large scale network scenario and a realistic traffic generation model. The results show improved performance in CCN networks considering download time, load balancing, content hit ratios, and others.

Evaluation of a Network Based Mobility Management Protocol: PMIPv6

The Proxy Mobile IPv6 (PMIPv6) is a network based mobility management protocol standard that was ratified recently by the Network-based Localized Mobility Management (NetLMM) working group of the Internet Engineering Task Force (IETF). PMIPv6 is a protocol that uses the same concepts as used in Mobile IPv6 (MIPv6), but modified to operate in the network part only instead of involving the Mobile Node (MN) as well. PMPv6 is claimed to posses a number of advantages over the host based mobility management protocols in use today, above all MIPv6. The main advantage of using PMIPv6 is the freeing up of the mobile host in doing any mobility related activities and thereby saving its resources. The saving of resources may result in their usage for other purposes or even enable otherwise capabilities restricted devices to operate in the PMIPv6 domains. Other advantages include reduced signaling traffic volume and no tunneled packets in the access network. These aspects become very important since the access networks in mobile networks usually are air interfaces. Further, PMIPv6 is also becoming a very attractive mobility management protocol for mobile network operators as seen by its inclusion in current 3 rd Generation Partnership Project (3GPP) standardization as a possible alternative mobility management protocol for the Long Term Evolution (LTE) technologies. In addition to qualitative analyses and comparisons, the work attempts to quantify these advantages to show the achieved benefits. The quantifications are done through measurements in a real test-bed which is installed with a PMIPv6 implementation developed as part of this work.

Performance evaluation of bandwidth and qos aware LTE uplink scheduler

A Long Term Evolution (LTE) eNodeB Medium Access Control (MAC) uplink scheduler is proposed in this paper for Single Carrier Frequency Division Multiple Access (SC-FDMA) as the uplink transmission scheme. Uplink scheduling algorithms available in literature commonly do not consider all the essential features of the LTE uplink. The proposed scheduler is shown to provide efficient allocation of radio resources to User Equipments (UEs) according to Quality of Service (QoS) of various traffic classes and the instantaneous channel conditions. The scheduler functionality is divided into Time Domain Packet Scheduling (TDPS) and Frequency Domain Packet Scheduling (FDPS). The proposed scheduler also supports multi-bearer UEs. The performance of the proposed scheduler is compared with common TDPS schedulers like Blind Equal Throughput (BET), Maximum Throughput (MT) and Proportional Fair (PF). The results show that the proposed scheduler guarantees provision of QoS to UEs and achieves an acceptable performance in terms of throughput.

Dimensioning of the LTE S1 interface

This paper presents analytical models to dimension the transport bandwidths for the S1 interface in the Long Term Evolution (LTE) Network. In this paper, we consider two major traffic types: elastic traffic and real time traffic. For each type of traffic, individual dimensioning models are proposed. For validating these analytical dimensioning models, a developed LTE system simulation model is used. The simulation results demonstrate that the proposed models can properly estimate the required performances and thus be able to be used for link dimensioning for various traffic and network scenarios.