Broadband Access

Top PDF Broadband Access:

DESIGNING COST-EFFICIENT TRANSPORT SOLUTIONS FOR FIXED AND MOBILE BROADBAND ACCESS NETWORK

DESIGNING COST-EFFICIENT TRANSPORT SOLUTIONS FOR FIXED AND MOBILE BROADBAND ACCESS NETWORK

This thesis undertakes a techno-economic evaluation of transport solutions for fixed and mobile broadband access. In the case of future mobile access networks, it is proposed to make use of backhaul architectures using fiber and microwave applied to Greenfield deployments and a copper-legacy backhaul infrastructure based on Brownfield migration, i.e. finding a way of using a legacy infrastructure to its full capacity. At the same time, protection deployments based on fiber-wireless schemes are recommended for future fixed broadband. The main contribution made by this thesis is to carry out a research investigation into the total investment cost of the broadband transport infrastructure. This will be determined by employing two sets of models to assess the capital and operational expenditures, (CAPEX and OPEX respectively), of mobile and fixed broadband access network operators. First, this involves a set of models for mobile broadband that are summarized in a general methodology that aims at providing: traffic forecasting, wireless deployment, mobile backhaul deployment and total cost assessment. It was found that, fiber-based backhaul through a Greenfield deployment is the most energy-efficient option. Furthermore, Brownfield reveals that copper-based backhaul can still play a key role if used up to its full capacity and sharply reduces the investment costs in infrastructure. Additionally, there is an examination of the main differences in cost and energy values between Greenfield and Brownfield. Finally, a methodology is employed for fixed broadband based on network dimensioning, failure costs and an assessment of the total cost of ownership. The models are used to assess five architectures that represent different protection schemes for fixed broadband. This research shows the economic benefits of using a hybrid protection scheme based on fiber-wireless architecture rather than fiber-based protection options and a sensitivity analysis is conducted to show that the extra CAPEX invested to protect the infrastructure might be recovered through the OPEX after a number of years. The results obtained in the thesis should be useful for network operators to plan both their fixed and mobile broadband access network infrastructure in the future.
Mostrar mais

119 Ler mais

A Multi-Objective Optimization Approach for Fault-Tolerance Provisioning in Multi-Radio Hybrid Wireless-Optical Broadband Access Networks

A Multi-Objective Optimization Approach for Fault-Tolerance Provisioning in Multi-Radio Hybrid Wireless-Optical Broadband Access Networks

Wireless-optical broadband-access networks (WOBANs), cur- rently being deployed at the access section, should integrate fault-tolerance in their design so that geographically con- tinuous wireless coverage can be provided without service breaks. In this paper we propose a joint wireless and optical fault-tolerance planning approach for WOBANs having mul- tiple radios in each router. The problem is formalized, as a multi-objective optimization problem, and a heuristic is pro- posed to solve this problem. Two fault-tolerance planning scenarios, where gateways are arranged differently in the risk groups, are analysed. It is shown that multi-radio routers can be exploited to improve the performance of WOBANs, providing wireless and optical fault-tolerance. Results also indicate that, when using our approach, a small increase in the number of radios can significantly decrease the total capacity required to provide any degree of fault-tolerance.
Mostrar mais

6 Ler mais

Radio over fiber broadband access networks architectures based on wavelength division multiplexing techniques

Radio over fiber broadband access networks architectures based on wavelength division multiplexing techniques

The abundant unlicensed spectrum around 60 GHz offers the potential for multi- gigabit indoor WPANs. Recently it was demonstrated that it is possible to produce low cost complementary metal–oxide–semiconductor (CMOS) components and circuits operating at 60 GHz, it was also demonstrated the wireless transmission of uncompressed broadband high definition television (HDTV) channels at 60 GHz. These advances combined with the increasing consumer demands for high-speed multimedia data communications are driving intense research on this area. However, 60 GHz WPAN networks cover relatively short distances (10-30 meters) and, additionally, 60 GHz signals cannot cross walls. Therefore, radio over fiber (RoF) technology, with its potential huge bandwidth, provides the perfect backbone technology for 60 GHz wireless WPANs. Nevertheless, to implement 60 GHz radio over fiber networks a number of key technological trends have to achieved, ranging from wireless networks to fiber optics transmission systems and supporting opto-electronic components. The 60 GHz WPANs standards already approved, ECMA-387 [1.4], IEEE 802.15.3c [1.5] and WirelessHD™ [1.6], consider both single carrier (SC) and multi carrier (MC) modulations schemes, especially the ones belonging to the orthogonal frequency division multiplexing (OFDM). It has been demonstrated that advanced RoF techniques can efficiently generate and deliver mm-wave carriers to simplified antenna stations. This thesis focus on optical mm- wave signal generation using external modulation of an optical carrier by means of lithium niobate (LiNbO 3 ) Mach- Zehnder modulators (MZM). The objective is to
Mostrar mais

162 Ler mais

Achieving Universal Access to Broadband

Achieving Universal Access to Broadband

When looking first at the possibility to extend the traditional universal service concept to encom- pass broadband access, two issues are relevant. The first issue is whether broadband can live up to the criteria for imposing universal service poli- cies on operators in the field. The second issue is concerned with the applicability of the universal service concept to the upcoming Next Generation Network infrastructures of communication net- works. The basic criterion for imposing universal service requirements is that the network technol- ogy is used by a majority of the population and that a universal service effort is necessary to reach the remaining minorities of the population. As stated in the 2005 universal service review, mobile communications do not live on this crite- rion as mobile has already reached app. 100% penetration in most European countries. Broad- band, on the other, hand was too little diffused in 2005 to be a technology that would exclude people if they did not have access. However, since 2005 broadband access has reached much higher rates of penetration. In the countries with the highest penetration – around 35% of the pop- ulation – the household reach is more than 75% and it could be argued that broadband access, therefore, should made subject to universal ser- vice rules. However, the differences between countries are vast and there are also large discre- pancies between urban and rural areas.
Mostrar mais

9 Ler mais

Leveraging Advances in Mobile Broadband Technology to Improve  Environmental Sustainability

Leveraging Advances in Mobile Broadband Technology to Improve Environmental Sustainability

In this paper, direct and indirect ways of how advances in broadband technology can help to improve environmental sustainability have been explored. The effects of a joint macro- and picocell deployment on the network energy efficiency, enabled by widely available broadband access, have been investigated. It was shown that a joint deployment of macrocells for area coverage and publicly accessible user- deployed residential picocells can reduce the total network energy consumption by up to 60% in urban areas for high data rate user demand based on today's technology. In addition, the impact of future technologies on the energy consumption was investigated, and it was shown that benefits of a joint macro- and picocell deployment will increase further to a maximum of up to 70% of the energy consumption as both technologies mature and the demand for high data rates increases.
Mostrar mais

5 Ler mais

Estratégias distribuídas para a coexistência de redes de banda larga sem fio em bandas não-licensiadas

Estratégias distribuídas para a coexistência de redes de banda larga sem fio em bandas não-licensiadas

The increasing demand for Internet data traffic in wireless broadband access networks requires both the development of efficient, novel wireless broadband access technologies and the allocation of new spectrum bands for that purpose. The introduction of a great number of small cells in cellular networks allied to the complimentary adoption of Wireless Local Area Network (WLAN) technologies in unlicensed spectrum is one of the most promising concepts to attend this demand. One alternative is the aggregation of Industrial, Science and Medical (ISM) unlicensed spectrum to licensed bands, using wireless networks defined by Institute of Electrical and Electronics Engineers (IEEE) and Third Generation Partnership Project (3GPP). While IEEE 802.11 (Wi-Fi) networks are aggregated to Long Term Evolution (LTE) small cells via LTE / WLAN Aggregation (LWA), in proposals like Unlicensed LTE (LTE-U) and LWA the LTE air interface itself is used for transmission on the unlicensed band. Wi-Fi technology is widespread and operates in the same 5 GHz ISM spectrum bands as the LTE proposals, which may bring performance decrease due to the coexistence of both technologies in the same spectrum bands. Besides, there is the need to improve Wi-Fi operation to support scenarios with a large number of neighbor Overlapping Basic Subscriber Set (OBSS) networks, with a large number of Wi-Fi nodes (i.e. dense deployments). It is long known that the overall Wi-Fi performance falls sharply with the increase of Wi-Fi nodes sharing the channel, therefore there is the need for introducing mechanisms to increase its spectral efficiency. This work is dedicated to the study of coexistence between different wireless broadband access systems operating in the same unlicensed spectrum bands, and how to solve the coexistence problems via distributed coordination mechanisms. The problem of coexistence between different networks (i.e. LTE and Wi-Fi) and the problem of coexistence between different networks of the same technology (i.e. multiple Wi-Fi OBSSs) is analyzed both qualitatively and quantitatively via system-level simulations, and the main issues to be faced are identified from these results. From that, distributed coordination mechanisms are proposed and evaluated via system-level simulations, both for the inter-technology coexistence problem and intra-technology coexistence problem. Results indicate that the proposed solutions provide significant gains when compare to the situation without distributed coordination.
Mostrar mais

159 Ler mais

Broadband: What do consumers want? Examining willingness-to-pay

Broadband: What do consumers want? Examining willingness-to-pay

Brown and Lee (2008) compare different factors influencing the adoption of broadband between several OECD countries in 2004 and 2005. While methodologically different to the above-mentioned studies by relying on ex-post observed market data, their findings suggest wireless data to neither complement nor substitute fixed internet access. The authors infer this from regression results from mobile price on fixed broadband diffusion, although suggesting that this relationship might change as mobile data transmission becomes faster over time. While the work of Cardona et al. (2009) is concerned primarily with market definition and estimation of demand elasticity in a regulatory context, the authors do suggest that mobile broadband might become a substitute to other forms of broadband access, once it gains traction.
Mostrar mais

25 Ler mais

Access to medicines

Access to medicines

13. The Essential Medicines, Vaccines, and Health Technology Unit, within the Area of Technology and Health Services Delivery (THS/EV), under the Office of the Assistant Director, promotes, coordinates, and implements technical cooperation activities aimed at strengthening national and regional capacity to improve accessibility, rational use, and regulation of essential medicines, and quality laboratory/blood services. Country offices provide direct technical cooperation in this area, specific to the needs of the country and with the support of THS/EV. Within its scope of work, THS/EV coordinates technical cooperation in access to essential public health supplies used in the delivery of health services. Interarea and interinstitutional cooperation are promoted to ensure that core areas of work are coherent with the overarching objectives of the priority regional programs such as HIV/AIDS, TB, and malaria; other priority emerging noncommunicable diseases; and the development of primary health care in the Region.
Mostrar mais

7 Ler mais

Broadband UHF RFID passive tag antenna for near-body applications

Broadband UHF RFID passive tag antenna for near-body applications

A simple, passive, low-profile RFID tag antenna is presented (BTA2) that operates near different kinds of difficult surfaces and in free space, keeping the compatibility with most of the[r]

8 Ler mais

Fuzzy algorithm to Mitigate Risk in the Assignment of Roles in a Wireless Network

Fuzzy algorithm to Mitigate Risk in the Assignment of Roles in a Wireless Network

This paper has thrown light on using the concepts of fuzzy logic for the assignment of roles in a wireless network . Since fuzzy logic is a tool used to mitigate risk involved in any assignment of resources or access to resources. It reduces to a large extent intrusions happening from unauthorized users. Apart from the above the paper has suggested a novel way to enhance the role assignment in a context aware environment. It would reduce the overload of loading Intrusion Detection Systems. This system can be used to depict the level of security also as a future enhancement.

6 Ler mais

Estimating equivalent bottom geoacoustial parameters from broadband inversion

Estimating equivalent bottom geoacoustial parameters from broadband inversion

Considering a semi-infinite fluid medium, the last arrival is related to the critical angle i.e. to the compressional sound speed of the equivalent medium. The amplitude of a single ray decreases with its time of arrival (or equivalently the grazing angle) giving a sample of the reflection coefficient value (related to attenuation) at power n, n being the number of bottom bounces. If it is possible to obtain experimentally the time dispersion and the attenuation law (filtered from the surface reflection losses), a rather straigtforward inversion will be possible to determine the compressional speed of the bottom and the attenuation coefficient of the equivalent medium. The previous analysis is valid at a single frequency. One can argue that the use of broadband signal is not consistent with the fact that the reflection coefficient depends on frequency. In fact, the analysis can be carried out for several frequency ranges, in which it is considered that the equivalent medium is valid.
Mostrar mais

6 Ler mais

Valores de referência para uma população urbana portuguesa da avaliação quantitativa por ultrasons do calcâneo

Valores de referência para uma população urbana portuguesa da avaliação quantitativa por ultrasons do calcâneo

homens e mulheres, estratificados por grupos de idade, os parâmetros de QUS no mesmo aparelho, um Sahara Clinical Sonometer da Hologic. Todas as avaliações foram efectuadas no Serviço de Higiene e Epidemiologia da Faculdade de Me- dicina da Universidade do Porto, por entrevis- tadores treinados. O aparelho possuía dois transdutores almofadados, posicionados co- axialmente, que funcionavam um como emissor e outro como receptor. Foi colocado um gel de con- tacto entre a pele e o transdutor. A região ti- biotársica e pé foram adequadamente posicio- nados e imobilizados. A QUS mede dois parâme- tros fundamentais, a atenuação do US (broadband ultrasound attenuation, BUA, expressa em dB/MHz) que é uma medida da variação da ate- nuação do US com a frequência da onda de som incidente e a velocidade do som (speed of sound, SOS, expressa em m/s) que traduz o tempo neces- sário para o US percorrer determinada distância através do calcâneo. O índice quantitativo do US (quantitative ultrasound index, QUI, expresso em %) e a densidade mineral óssea estimada (estima- ted bone mineral density, EBMD, expressa em g/cm 2 ) resultam da combinação dos dois primei-
Mostrar mais

9 Ler mais

Minimal Access Surgery

Minimal Access Surgery

NOTES can also be classified as “pure NOTES “ where only natural orifice is used, Rendezvous NOTES where more than one portal of entry is used to complete the surgery like transabdominal laparoscopy port, and Robotic NOTES where Da vinci surgical robot is used to perform various procedures. The most successful route is transvaginal as closure is easy and it is expansile. The basic idea in single incision laparoscopic surgery is to introduce all necessary instruments through a single incision. SILS can be seen as a bridge between multiport laparoscopy and NOTES. Potential advantages of SILS are: better cosmesis, less trauma, and less chances of incisional hernia. Main disadvantages over conventional multiport surgeries are: Loss of triangulation, clashing of instruments and lack of tissue retraction by assistant surgeon. SILS uses umbilicus as a portal of entry. Transumbilical approach may be associated with high incidence of port site hernia and wound infection. Therefore, Remote access laparoscopic surgery (REAL) was developed where the pubic line is used as a distant portal of entry Main difference between NOTES and SILS is NOTES leaves no scar, while SILS leaves one small scar at the umbilicus.
Mostrar mais

2 Ler mais

J. Microw. Optoelectron. Electromagn. Appl.  vol.16 número3

J. Microw. Optoelectron. Electromagn. Appl. vol.16 número3

In this paper a method based on quantum particle swarm optimization algorithm has been successfully used for synthesis of a non-uniformly spaced linear array for broadband frequency invariant far-field pattern with fixed SLL and different constant FNBW (main beam). Simulated results obtained clearly show a great deal between the desired and obtained specifications. This technique works well for different width of main beam with different antennas for both cases. This technique is suitable to maintain constant SLL and nearly constant FNBW for both cases as SLL and FNBW are contradictory to each other. Algorithm finds suitable excitation current amplitudes and spacing between the elements to obtain the desired values. From the obtained results of the above figures it is proved that QPSO algorithm is more suitable for broadband frequency invariant pattern of linear antenna array. This work can be extended to other type of arrays. This proposed technique is suitable to generate frequency invariant pattern with different main beam shapes also.
Mostrar mais

13 Ler mais

Effectiveness of Cross-Bord er Corporate Payments

Effectiveness of Cross-Bord er Corporate Payments

For every business, development of a Corporate Foreign Exchange, Payments and Risk Management Policy Manual is an essential step for structuring critical cross-border corporate payment[r]

3 Ler mais

 Glimpses for Effective implementation of  Virtual Trainer

Glimpses for Effective implementation of Virtual Trainer

New technology is changing our education and learning styles. The innovations and development brought by the new technologies in our information Technology era have started to appear in education. Virtual training has become a core training strategy around the world in recent years, with extending to a broad cross-section of knowledge sharing with in organization at different places through out the world.. Ready access to information and training lectures on the web, sharing concepts and suggestions across the Internet, joint lecturing across distant locations, create novel responsibilities for Employees and trainers and change the learning and training environment everlastingly. Many of the pedagogical changes have already occurred at the virtual trainer without much effort, seminars are taking advantage of on-line information; work plans may be submitted from home and discussed with the subject experts or with peers in an interactive distant mode.
Mostrar mais

9 Ler mais

ACCESS - Criação e Consulta de uma Tabela

ACCESS - Criação e Consulta de uma Tabela

Contrariamente ao EXCEL que quando abre tem uma folha de cálculo já pronta a utilizar, quando se abre o ACCESS, temos que referir imediatamente um ficheiro onde ficará guardada a base de dados onde vamos trabalhar. No caso de não termos nenhuma previamente criada, teremos que criar uma base de dados vazia seleccionando “Blank Database” e clicamos OK. Aparece um Browser onde escolhemos o nome, com extensão .mdb, e local de gravação da nossa BD que

9 Ler mais

Realization of Broadband Matched Filter Structures Based on Dual Networks

Realization of Broadband Matched Filter Structures Based on Dual Networks

The transmission and reflection characteristics of dual net- works offer the possibility to build filter structures, which are matched frequency-independently or at least over a broad band with respect to the input. These filters structures contain a parallel connection of two dual networks, using their frequency-independent reciprocal input impedances to achieve the broadband input matching of the resulting filter circuit. The decoupling of both output ports of the resulting filter structure is an additional feature of these structures. All this basic features are independent of the chosen filter charac- teristics of the dual networks and of their realization method. They can be realized by using concentrated elements, as well as planar transmission line elements. Even a mixture of both techniques is possible, without influencing their duality. Es- pecially for the use as a differentiating stage in pulse shaping networks, a high-pass filter structure is presented, which is based on coupled line structures. Beside the basic properties of a broadband matched input and the two decoupled out- puts, this structure additionally provides two identical pulse signals with opposite polarities at their outputs.
Mostrar mais

5 Ler mais

Evaluation of primary health care for children under 5 years old in the municipality of lagarto-se          /              Avaliação da assistência primária à saúde das crianças menores de 5 anos no município de Lagarto-SE

Evaluation of primary health care for children under 5 years old in the municipality of lagarto-se / Avaliação da assistência primária à saúde das crianças menores de 5 anos no município de Lagarto-SE

Objective: to evaluate the effectiveness of primary care for children under five years of age enrolled in a Family Health Clinic, Lagarto-SE. Method: This is a results research, quantitative approach and cross- sectional design, in which the Primary Care Assessment Tool - Child Version was used to assess the attributes of access, longitudinality, coordination, completeness, family orientation and community orientation. Results: 50 adults were interviewed, responsible for children up to five years of age enrolled in the service. The evaluation was positive for the degree of affiliation and the coordination-information system attribute, and the others did not reach the minimum reference score. Conclusion: attributes reveal barriers to service access, lack of continuity of care, fragility in referral and counter-referral, and commitment to communication between health-patient professionals.
Mostrar mais

9 Ler mais

A Framework for Predicate Based Access Control Policies in Infrastructure as a Service Cloud

A Framework for Predicate Based Access Control Policies in Infrastructure as a Service Cloud

Role: Role plays a vital role in controlling access. Even the predicate – based access control model presented in this paper can enjoy the advantages of role based access control. While performing a particular task a user who belongs to a role can gain access to a particular tuple only. It is true with all users of all roles. An important observation is here is that different users of a similar role also can involve in different process instances. Thus it is very clear that the concept of role and the concept of instance- based user group are distinct. They are not interchangeable.
Mostrar mais

9 Ler mais

Show all 2107 documents...

temas relacionados