LTE Optimization and Resource Management in Wireless Heterogeneous Networks

Mobile communication technology is evolving with a great pace. The development of the Long Term Evolution (LTE) mobile system by 3GPP is one of the milestones in this direction. This work highlights a few areas in the LTE radio access network where the proposed innovative mechanisms can substantially improve overall LTE system performance. In order to further extend the capacity of LTE networks, an integration with the non-3GPP networks (e.g., WLAN, WiMAX etc.) is also proposed in this work. Moreover, it is discussed how bandwidth resources should be managed in such heterogeneous networks. The work has purposed a comprehensive system architecture as an overlay of the 3GPP defined SAE architecture, effective resource management mechanisms as well as a Linear Programming based analytical solution for the optimal network resource allocation problem. In addition, alternative computationally efficient heuristic based algorithms have also been designed to achieve near-optimal performance

A preconditioned iterative method for solving systems of nonlinear equations having unknown multiplicity

A modification to an existing iterative method for computing zeros with unknown multiplicities of nonlinear equations or a system of nonlinear equations is presented. We introduce preconditioners to nonlinear equations or a system of nonlinear equations and their corresponding Jacobians. The inclusion of preconditioners provides numerical stability and accuracy. The different selection of preconditioner offers a family of iterative methods. We modified an existing method in a way that we do not alter its inherited quadratic convergence. Numerical simulations confirm the quadratic convergence of the preconditioned iterative method. The influence of preconditioners is clearly reflected in the numerically achieved accuracy of computed solutions.Peer ReviewedPostprint (published version

LTE-Optimierung und Ressourcen-Management in Drahtlosen Heterogenen Netzen

Mobile communication technology is evolving with a great pace. The development of the Long Term Evolution (LTE) mobile system by 3GPP is one of the milestones in this direction. This work highlights a few areas in the LTE radio access network where the proposed innovative mechanisms can substantially improve overall LTE system performance. In order to further extend the capacity of LTE networks, an integration with the non-3GPP networks (e.g., WLAN, WiMAX etc.) is also proposed in this work. Moreover, it is discussed how bandwidth resources should be managed in such heterogeneous networks. The work has purposed a comprehensive system architecture as an overlay of the 3GPP defined SAE architecture, effective resource management mechanisms as well as a Linear Programming based analytical solution for the optimal network resource allocation problem. In addition, alternative computationally efficient heuristic based algorithms have also been designed to achieve near-optimal performance

Successful Endoscopic Treatment of Bouveret Syndrome in a Patient with Choledochoduodenal Fistula Complicating Duodenal Ulcer

Introduction. Cholecystoduodenal fistulas represent the most common type of bilioenteric fistulas while choledochoduodenal fistulas account for only 1–25% of cases. Bilioenteric fistula cases are associated with cholelithiasis and are rarely associated with duodenal peptic ulcers. Here we present the first case of Bouveret syndrome secondary to choledochoduodenal fistula complicating peptic duodenal ulcer managed successfully via endoscopic mechanical lithotripsy. Case. 86-year-old male with a medical history significant for coronary artery disease and stage 3 colorectal cancer status after resection and chemoradiation presented with intractable sharp abdominal pain worse postprandially for one week in duration, associated with early satiety, anorexia, and 5 lbs weight loss in one week. CT abdomen showed possible choledochoduodenal fistula and a distended stomach. An esophagogastroduodenoscopy (EGD) was performed revealing a large 2.5–3 cm stone lodged in the duodenal bulb at the base of duodenal ulcer with a fistula opening beneath it. The stone was extracted in 2 pieces via mechanical lithotripsy. Endoscopic ultrasound of the CBD revealed Rigler’s triad. Conclusion. Bouveret syndrome is mostly associated with cholecystoduodenal fistula and has high mortality and morbidity due to underlying comorbid conditions and elderly age. Patients are not always fit for surgical management, and endoscopic management is not always successful

Federated cloud resource management: review and discussion

Federation of clouds is the future of cloud computing, mobile cloud computing, Internet of things, and big data applications. The utilization of federated resources is envisioned to increase the quality of service, cost benefits, and reliability. Resource management in the federation of multiple clouds is a pressing issue owing to the lack of cross-domain knowledge, security, trust, and administrative policies. This study classifies these resource management functions in the federated cloud environment into resource pricing, resource discovery, resource selection, resource monitoring, resource allocation, and disaster management. Each federated resource management function is discussed, and insights into state-of-the-art research are then provided. These resource management functions are also compared based on the performance metrics that are suitable for an individual function. Finally, we indicate the open challenges for further research with regard to each classified resource management function

A preconditioned iterative method for solving systems of nonlinear equations having unknown multiplicity

A modification to an existing iterative method for computing zeros with unknown multiplicities of nonlinear equations or a system of nonlinear equations is presented. We introduce preconditioners to nonlinear equations or a system of nonlinear equations and their corresponding Jacobians. The inclusion of preconditioners provides numerical stability and accuracy. The different selection of preconditioner offers a family of iterative methods. We modified an existing method in a way that we do not alter its inherited quadratic convergence. Numerical simulations confirm the quadratic convergence of the preconditioned iterative method. The influence of preconditioners is clearly reflected in the numerically achieved accuracy of computed solutions.Peer Reviewe

A recursive orchestration and control framework for large-scale, federated SDN experiments: the FELIX architecture and use cases

Programmable networks are a substantial part of current R&D on future internet (FI) in Europe and worldwide, with considerable impact generated by large-scale test bed infrastructures. In such test beds, researchers validate proof-of-concept prototypes for new algorithms and mechanisms for efficiently controlling and managing network resources. One of the key domains for FI research is software-defined networking (SDN), which creates innovations in existing Internet architectures by shifting the control and logic outside the network equipment to Data Centres. International cooperation among leading research centres in Europe, Americas and Asia is key to validate SDN foundations and tools. EU and Japan have jointly funded the FELIX project (federated test-beds for large-scale infrastructure experiments), which defines a common control and orchestration framework to manage federated FI test beds across continents. This framework enables an experimenter to (i) request and obtain resources across different test bed infrastructures dynamically; (ii) manage and control the network paths connecting the federated SDN test beds; (iii) monitor the underlying resources and (iv) use distributed applications executed on the federated infrastructures. This paper describes the high-level architecture of the FELIX framework and details six use cases that will be employed for validation. We present our analysis and end-user considerations, highlighting the necessity for resource accessibility and coherent use of physical connections over a large-scale test bed where different control technologies such as OpenFlow and the network service interface (NSI) are simultaneously used

Design and Implementation of an OpenFlow Hardware Abstraction Layer

OpenFlow is a leading standard for Software-Defined Networking (SDN) and has already played a significant role in reshaping network infrastructures. However, a wide range of existing provider domains is still not equipped with a framework that supports wider deployment of an OpenFlow-based control plane beyond Ethernet- dominated networks. We address this gap by introducing a Hardware Abstraction Layer (HAL) which can transform legacy network elements into OpenFlow capable devices. This paper details the functional architecture of HAL, discusses the key design aspects and explains how HAL can support a number of network device classes. In addition, this paper presents the implementation details of HAL for hardware platforms such as DOCSIS (Data over Cable Service Interface Specification) and DWDM (Dense Wave- length Division Multiplexing) which have so far received little attention by the OpenFlow research community despite their wide real-world deployment. Categorie