184 research outputs found

    An Innovative RAN Architecture for Emerging Heterogeneous Networks: The Road to the 5G Era

    Full text link
    The global demand for mobile-broadband data services has experienced phenomenal growth over the last few years, driven by the rapid proliferation of smart devices such as smartphones and tablets. This growth is expected to continue unabated as mobile data traffic is predicted to grow anywhere from 20 to 50 times over the next 5 years. Exacerbating the problem is that such unprecedented surge in smartphones usage, which is characterized by frequent short on/off connections and mobility, generates heavy signaling traffic load in the network signaling storms . This consumes a disproportion amount of network resources, compromising network throughput and efficiency, and in extreme cases can cause the Third-Generation (3G) or 4G (long-term evolution (LTE) and LTE-Advanced (LTE-A)) cellular networks to crash. As the conventional approaches of improving the spectral efficiency and/or allocation additional spectrum are fast approaching their theoretical limits, there is a growing consensus that current 3G and 4G (LTE/LTE-A) cellular radio access technologies (RATs) won\u27t be able to meet the anticipated growth in mobile traffic demand. To address these challenges, the wireless industry and standardization bodies have initiated a roadmap for transition from 4G to 5G cellular technology with a key objective to increase capacity by 1000Ã? by 2020 . Even though the technology hasn\u27t been invented yet, the hype around 5G networks has begun to bubble. The emerging consensus is that 5G is not a single technology, but rather a synergistic collection of interworking technical innovations and solutions that collectively address the challenge of traffic growth. The core emerging ingredients that are widely considered the key enabling technologies to realize the envisioned 5G era, listed in the order of importance, are: 1) Heterogeneous networks (HetNets); 2) flexible backhauling; 3) efficient traffic offload techniques; and 4) Self Organizing Networks (SONs). The anticipated solutions delivered by efficient interworking/ integration of these enabling technologies are not simply about throwing more resources and /or spectrum at the challenge. The envisioned solution, however, requires radically different cellular RAN and mobile core architectures that efficiently and cost-effectively deploy and manage radio resources as well as offload mobile traffic from the overloaded core network. The main objective of this thesis is to address the key techno-economics challenges facing the transition from current Fourth-Generation (4G) cellular technology to the 5G era in the context of proposing a novel high-risk revolutionary direction to the design and implementation of the envisioned 5G cellular networks. The ultimate goal is to explore the potential and viability of cost-effectively implementing the 1000x capacity challenge while continuing to provide adequate mobile broadband experience to users. Specifically, this work proposes and devises a novel PON-based HetNet mobile backhaul RAN architecture that: 1) holistically addresses the key techno-economics hurdles facing the implementation of the envisioned 5G cellular technology, specifically, the backhauling and signaling challenges; and 2) enables, for the first time to the best of our knowledge, the support of efficient ground-breaking mobile data and signaling offload techniques, which significantly enhance the performance of both the HetNet-based RAN and LTE-A\u27s core network (Evolved Packet Core (EPC) per 3GPP standard), ensure that core network equipment is used more productively, and moderate the evolving 5G\u27s signaling growth and optimize its impact. To address the backhauling challenge, we propose a cost-effective fiber-based small cell backhaul infrastructure, which leverages existing fibered and powered facilities associated with a PON-based fiber-to-the-Node/Home (FTTN/FTTH)) residential access network. Due to the sharing of existing valuable fiber assets, the proposed PON-based backhaul architecture, in which the small cells are collocated with existing FTTN remote terminals (optical network units (ONUs)), is much more economical than conventional point-to-point (PTP) fiber backhaul designs. A fully distributed ring-based EPON architecture is utilized here as the fiber-based HetNet backhaul. The techno-economics merits of utilizing the proposed PON-based FTTx access HetNet RAN architecture versus that of traditional 4G LTE-A\u27s RAN will be thoroughly examined and quantified. Specifically, we quantify the techno-economics merits of the proposed PON-based HetNet backhaul by comparing its performance versus that of a conventional fiber-based PTP backhaul architecture as a benchmark. It is shown that the purposely selected ring-based PON architecture along with the supporting distributed control plane enable the proposed PON-based FTTx RAN architecture to support several key salient networking features that collectively significantly enhance the overall performance of both the HetNet-based RAN and 4G LTE-A\u27s core (EPC) compared to that of the typical fiber-based PTP backhaul architecture in terms of handoff capability, signaling overhead, overall network throughput and latency, and QoS support. It will also been shown that the proposed HetNet-based RAN architecture is not only capable of providing the typical macro-cell offloading gain (RAN gain) but also can provide ground-breaking EPC offloading gain. The simulation results indicate that the overall capacity of the proposed HetNet scales with the number of deployed small cells, thanks to LTE-A\u27s advanced interference management techniques. For example, if there are 10 deployed outdoor small cells for every macrocell in the network, then the overall capacity will be approximately 10-11x capacity gain over a macro-only network. To reach the 1000x capacity goal, numerous small cells including 3G, 4G, and WiFi (femtos, picos, metros, relays, remote radio heads, distributed antenna systems) need to be deployed indoors and outdoors, at all possible venues (residences and enterprises)

    Instantaneous Flood Events Data Analyses in Northern Pakistan

    Get PDF
    In large watersheds of Pakistan, a proper flood intensity assessment is a most important concern for many water management applications. The present study investigates the possible best-fit probability distributions technique of uttermost flood events using more than 30 years data (except Mastuj Bridge station) from 15 stream flow stations in northern Pakistan, operated and maintained by Surface Water Hydrology Project (SWHP), WAPDA. Different statistical distribution model, were used to estimate design floods for risk planning and the design of important civil infrastructure. Method of moments was used for estimation of parameters of selective distributions. Four goodness-of-fit statistics test K, A2, χ2 and Root mean square error (RMSE) were applied to evaluate the most appropriate probability distribution. P3, LP3, GEV, and LN were determined best fit distribution model. Among the eight-probability distribution’s P3 fitted 33.3% of the stations, LP3 also fitted 33.3% of the stations, GEV fitted 26.7% of the stations and LN fitted 6.7% of the stations. The more practical result for peak flood were calculated for recurrence intervals of 5-year, 25-year, 50-year, 100-year, 500-year and 1000-years respectively. In future before planning and designing any project such as Hydropower, irrigation systems, Dike, flood disaster assessment and management at Indus and adjacent rivers, P3, LP3, GEV and LN distributions results should be considered more reliable on these locations

    Risk assessment of failure of outdoor high voltage polluted insulators under combined stresses near shoreline

    Get PDF
    The aim of this paper is to investigate the various effects of climate conditions on outdoor insulators in coastal areas as a result of saline contamination under acidic and normal cold fog, determining significant electrical and physico-chemical changes on the insulator surface and considering the effect of discharge current, electric field distribution and surface roughness. To replicate similar conditions near the shoreline, experimental investigations have been carried out on insulation materials with the combined application of saline contamination and acidic or normal cold fog. The test samples included silicone rubber (SiR), ethylene propylene diene monomer (EPDM) and high-density polyethylene (HDPE), which were used as reference. The materials are of the same composition as those used in real-life outdoor high voltage insulators. All samples were aged separately in an environmental chamber for 150 h for various saline contaminations combined with acidic and normal cold fog, and were generated by means of the adopted experimental setup. This analysis represented conditions similar to those existing near the shoreline exposed to saline and acid spray during winter and early spring. Electric field and discharge current along polymeric samples were examined under acidic and normal cold fog. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopic (SEM) were used to probe the physico-chemical changes on the samples surface and investigate the hydrophobicity recovery property after aging tests. Finally, a comparative study was carried out on polymeric samples before and after being exposed to the acidic and normal cold fog based on the results obtained from the experiment. Research data may provide references for the better prediction of surface degradation as well as for the better material coating and design of external insulation

    The User-Education Programs in the University Libraries of Khyber Pakhtunkhwa: A Quantitative Study

    Get PDF
    This study evaluated the User Education Programs (UEPs) in the Public Sector Universities’ libraries of Khyber Pakhtunkhwa. This study aimed to explore the overall scenario of the user’s education, to probe how much time is allotted for UEPs, what methods and approaches of UEPs are in practice and to suggest the measures for improving user education programs in the libraries. The data from the target sample was collected through questionnaire which was then analyzed as per the objectives of the study. The study identified 34 central and departmental libraries in the six universities of the Southern Part of the province of Khyber Pakhtunkhwa. All the universities’ central and departmental libraries offered users education programs to their users. The UEPs were conducted by the library staff and the faculty members of the respective departments. The most adopted methods or approaches for user education programs were lecture library tours and demonstration. Most of the respondents suggested that there should be a written policy for UEPs, the instruction sessions should be conducted on regular basis, and the UEPs should be organized at the departmental level

    Acetaminophen induced Steven Johnson syndrome-toxic epidermal necrolysis overlap

    Get PDF
    Steven Johnson Syndrome and Toxic Epidermal Necrolysis are rare but severe form of hypersensitivity inflammatory reactions to multiple offending agents including drugs. Acetaminophen is extensively used due to its analgesic and anti-pyretic properties. It is rendered to be relatively safe, with hepatotoxicity considered to be the major adverse effect. However, very few cases of Steven Johnson Syndrome and Toxic Epidermal Necrolysis have been reported with acetaminophen usage in the past. We present the case of a 40 years old lady who developed an overlap of the two condition after taking several doses of acetaminophen for fever. She presented with widespread maculopapular rash, stinging in the eyes, oral mucosal ulcerations and high grade fever. She was successfully treated with corticosteroid therapy along with the supportive treatment. This case addresses the fact, that severe hypersensitivity reactions can occur with acetaminophen which can be potentially life threatening

    A Simple and Cost-Effective EPON-Based Next Generation Mobile Backhaul RAN Architecture

    Full text link
    This study proposes a novel, simple and cost-effective PON-based next generation mobile backhaul RAN architecture that enables redistribution of some of the intelligence currently centralized in the Mobile Packet Core (MPC) platform out into the access nodes of the RAN. Specifically, this work proposes a fully distributed ring-based EPON architecture that enables the support of a converged PON-4G/5G mobile WiMAX/LTE access networking transport infrastructure to seamlessly backhaul both mobile and wireline multimedia traffic and services

    Effect of annealing temperature on the microstructure and morphology of BaZr0.45Ti0.55O3 thin films using the sol-gel method

    Get PDF
    Abstrak. Ferroelektrik merupakan bahan elektronik khususnya dielektrik yang dapat diaplikasikan sebagai kapasitor. Ferroeletrik mempunyai kemampuan mengubah arah medan listrik internalnya dengan menggunakan medanl istrik yang sesuai. Barium titanat merupakan bahan yang bersifat ferroelektrik yang dapat didoping dengan bahan zirconium dan dapat dibuat dalam bentuk film tipis. Penambahan doping zirconium pada barium titanat akan meningkatkan konstanta dielektrik bahan. Pembuatan film tipis Barium Zirkoniun Titanat dengan komposisi (BaZr0.45Ti0.55O3) telah berhasil dibuat dengan menggunakan metode sol-gel. Variasi suhu annealing yaitu 600oC dan 650oC dengan waktu tahan 1 jam dan dikarakterisasi menggunakan difraksi sinar-X (XRD) dan scanning electron microscopy (SEM). Hasil karakterisasi XRD mendapatkan parameter kisi a = b = 3,97Ȧ danc = 4,25 Ȧ sehingga struktur kristalnya adalah tetragonal. Tingkat kekristalan semakin tinggi dengan bertambahnya suhu annealing yang ditandai dengan meningkatnya intensitas. Karakterisasi SEM menunjukkan pada suhu annealing 600oC ukuran butiran belum terlihat jelas sehingga tidak dapat ditentukan ukuran butirannya. Pada suhu 650oC ukuran butirannya dapat ditentukan dengan nilai ukuran butiran rata-ratanya adalah sekitar 134,5 nm. Abstract. Ferroelectric is an electronic material, the dielectric in particular, which can be applied as a capacitor. Ferroelectric is able to change the direction of its internal electric field by the use of a suitable electric field. Barium Titanate is a ferroelectric material which can be doped with zirconium and made in the form of a thin film. The addition of zirconium doping to Barium Titanate will increase the dielectric constant of the material. The making of Barium Zirconiun Titanate thin film with the composition (BaZr0,45Ti0,55O3) has been successfully prepared using the sol-gel method. The annealing temperature variations are 600oC and 650oC with a 1 hour holding time and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD characterization results obtain lattice parameters of a = b = 3.97 and c = 4.25 Ȧ, and thereby, the crystal structure is tetragonal. The crystallinity level is highly increasing with increased annealing temperature, indicated by increased intensity. SEM characterization shows that at annealing temperature of 600oC, the grain size is not clearly visible, so the grain size cannot be determined. At a temperature of 650oC, the grain size can be determined with the average grain size of about 134.5 nm

    Treatment of a Rare Vascular Complication of Coronary Stenting in an Octagenarian

    Get PDF
    The ability of drug-eluting stent (DES) to inhibit intimal proliferation has resulted in a massive increase in their usage over the years. However, it is known that the application of DES can alter the normal cascade of vascular healing, resulting in delayed endothelialisation with risk of vascular complications. Coronary artery aneurysms (CAN) are defined as more than 50% dilatation of the coronary artery compared to the reference vessel diameter with the reported incidence after percutaneous intervention (PCI) being only around 0.35 to 6.0%. Previously, CAN had been reported with the use of bare metal stent secondary to stretch, stent fracture and dissection. However, recently, increasing number of cases have been reported describing CAN after DES implantation. To the best of the authors\u27 knowledge, they present the first case from Pakistan of a left anterior descending coronary artery aneurysm after DES implantation treated successfully with stenting under intravascular ultrasound guidance

    Role of assessment for retreatment with transarterial chemoembolization score in decision of retreatment with trans-arterial chemo-embolization sessions in patients with hepatocellular carcinoma

    Get PDF
    Background: The objective behind this study was to determine that Assessment for Retreatment with Transarterial chemoembolization (ART) score is really applicable in patients with hepatocellular carcinoma.Methods: A cross sectional observational study was conducted on all patients with hepatocellular carcinoma of intermediate stage and undergone ≥2 Transarterial chemoembolization. ART score was assessed before and after each session of Transarterial chemoembolization. Multi-logistic regression analysis was performed to compare the final outcome of patients with ART score of ≥2.5 into groups with two and more than two Trans-arterial chemo-embolization sessions.Results: A total of 100 HCC patients were recruited for final analysis. Our study participants consisted of total 100 HCC patients. Mean Child Pugh score was 6.1±0.95. In our study, most of the study participants (n=63) had ART score of less than 1.5 as compared to ART score \u3e2.5 (n=37). A significant proportion of patients with ART score of \u3c1.5 prior to second Trans-arterial chemo-embolization had better median survival as compared to patients with ART score of \u3e2.5, p-value\u3c0.001. Patients with ART score of more than 2.5 did not show any survival benefit after having 3rd or 4th Trans-arterial chemo-embolization session, p=0.47.Conclusions: Our study findings suggest that those HCC patients who receive multiple sessions of TACE with a low ART score have more favourable outcomes with increased survival rate

    FPGA based intelligent co-operative processor in memory architecture

    Get PDF
    Copyright International Association of EngineersIn a continuing effort to improve computer system performance, Processor-In-Memory (PIM) architecture has emerged as an alternative solution. PIM architecture incorporates computational units and control logic directly on the memory to provide immediate access to the data. To exploit the potential benefits of PIM, a concept of Co-operative Intelligent Memory (CIM) was developed by the intelligent system group of University of Hertfordshire, based on the previously developed Co-operative Pseudo Intelligent Memory (CPIM). This paper provides an overview on previous works (CPIM, CIM) and realization of CPIM over two scenarios, cumulative successive addition, and non-cumulative successive addition, using Nexar 2004 EDS tool as a design environment to target device (SPARTAN II, XC2S300E-6PQ208C). The performance (speedup) is then measured against an SISD without significant performance acceleration methods to ensure a speedup assessment obtained against base-line architecture
    • …
    corecore