110 research outputs found
Future Trends and Challenges for Mobile and Convergent Networks
Some traffic characteristics like real-time, location-based, and
community-inspired, as well as the exponential increase on the data traffic in
mobile networks, are challenging the academia and standardization communities
to manage these networks in completely novel and intelligent ways, otherwise,
current network infrastructures can not offer a connection service with an
acceptable quality for both emergent traffic demand and application requisites.
In this way, a very relevant research problem that needs to be addressed is how
a heterogeneous wireless access infrastructure should be controlled to offer a
network access with a proper level of quality for diverse flows ending at
multi-mode devices in mobile scenarios. The current chapter reviews recent
research and standardization work developed under the most used wireless access
technologies and mobile access proposals. It comprehensively outlines the
impact on the deployment of those technologies in future networking
environments, not only on the network performance but also in how the most
important requirements of several relevant players, such as, content providers,
network operators, and users/terminals can be addressed. Finally, the chapter
concludes referring the most notable aspects in how the environment of future
networks are expected to evolve like technology convergence, service
convergence, terminal convergence, market convergence, environmental awareness,
energy-efficiency, self-organized and intelligent infrastructure, as well as
the most important functional requisites to be addressed through that
infrastructure such as flow mobility, data offloading, load balancing and
vertical multihoming.Comment: In book 4G & Beyond: The Convergence of Networks, Devices and
Services, Nova Science Publishers, 201
4G Technology Features and Evolution towards IMT-Advanced
Kiinteiden- ja mobiilipalveluiden kysyntä kasvaa nopeasti ympäri maailmaa. Älykkäiden päätelaitteiden, kuten iPhone:n ja Nokia N900:n markkinoilletulo yhdistettynä näiden korkeaan markkinapenetraatioon ja korkealuokkaiseen käyttäjäkokemukseen lisäävät entisestään palveluiden kysyntää ja luovat tarpeen jatkuvalle innovoinnille langattomien teknologioiden alalla tavoitteena lisäkapasiteetin ja paremman palvelunlaadun tarjoaminen.
Termi 4G (4th Generation) viittaa tuleviin neljännen sukupolven mobiileihin langattomiin palveluihin, jotka International Telecommunications Union:in Radiocommunication Sector (ITU-R) on määritellyt ja nimennyt International Mobile Telecommunications-Advanced (IMT-Advanced). Nämä ovat järjestelmiä, jotka pitävät sisällään IMT:n ne uudet ominaisuudet, jotka ylittävät IMT-2000:n vaatimukset. Long Term Evolution-Advanced (LTE-Advanced) ja IEEE 802.16m ovat IMT-A sertifiointiin lähetetyt kaksi pääasiallista kandidaattiteknologiaa.
Tässä diplomityössä esitellään kolmannen sukupolven järjestelmien kehityspolku LTE:hen ja IEEE 802.16e-2005 asti. Lisäksi työssä esitetään LTE-Advanced:n ja IEEE 802.16m:n uudet vaatimukset ja ominaisuudet sekä vertaillaan näiden lähestymistapoja IMT-A vaatimusten täyttämiseksi. Lopuksi työssä luodaan katsaus LTE ja IEEE 802.16e-2005 (markkinointinimeltään Mobile WiMAX) -järjestelmien markkinatilanteeseen.The demand for affordable bandwidth in fixed and mobile services is growing rapidly around the world. The emergence of smart devices like the iPhone and Nokia N900, coupled with their high market penetration and superior user experience is behind this increased demand, inevitably driving the need for continued innovations in the wireless data technologies industry to provide more capacity and higher quality of service.
The term "4G" meaning the 4th Generation of wireless technology describes mobile wireless services which have been defined by the ITU's Radiocommunication Sector (ITU-R) and titled International Mobile Telecommunications-Advanced (IMT-Advanced). These are mobile systems that include the new capabilities of IMT that go beyond those of IMT-2000. Long Term Evolution-Advanced (LTE-Advanced) and IEEE 802.16m are the two main candidate technologies submitted for IMT-Advanced certification.
This thesis reviews the technology roadmap up to and including current 3G systems LTE from the 3rd Generation Partnership Project (3GPP) and IEEE 802.16e-2005 from the Institute of Electrical and Electronics Engineers (IEEE). Furthermore, new requirements and features for LTE-Advanced and IEEE 802.16m as well as a comparative approach towards IMT-Advanced certification are presented. Finally, the thesis concludes with a discussion on the market status and deployment strategies of LTE and IEEE 802.16e-2005, or Mobile WiMAX as it is being marketed
A Technical and Market study for WiMAX
Worldwide Interoperability for Microwave Access (WiMAX) is a broadband wireless technology based on IEEE 802.16-2004 and IEEE 802.16e-2005. This thesis is a study of WiMAX technology and market. The background of WiMAX development is introduced and opportunities and challenges for WiMAX are analyzed in the beginning. Then the thesis focuses on an overview of WiMAX technology, which addresses the physical layer, MAC layer and WiMAX network architecture. The deployment status is investigated in the fourth chapter. Both product development situation and market status are discussed in this section. In the last chapter, the future development trend of WiMAX is addressed
Mobility and Handoff Management in Wireless Networks
With the increasing demands for new data and real-time services, wireless
networks should support calls with different traffic characteristics and
different Quality of Service (QoS)guarantees. In addition, various wireless
technologies and networks exist currently that can satisfy different needs and
requirements of mobile users. Since these different wireless networks act as
complementary to each other in terms of their capabilities and suitability for
different applications, integration of these networks will enable the mobile
users to be always connected to the best available access network depending on
their requirements. This integration of heterogeneous networks will, however,
lead to heterogeneities in access technologies and network protocols. To meet
the requirements of mobile users under this heterogeneous environment, a common
infrastructure to interconnect multiple access networks will be needed. In this
chapter, the design issues of a number of mobility management schemes have been
presented. Each of these schemes utilizes IP-based technologies to enable
efficient roaming in heterogeneous network. Efficient handoff mechanisms are
essential for ensuring seamless connectivity and uninterrupted service
delivery. A number of handoff schemes in a heterogeneous networking environment
are also presented in this chapter.Comment: 28 pages, 11 figure
Assessment and Real Time Implementation of Wireless Communications Systems and Applications in Transportation Systems
Programa Oficial de Doutoramento en Tecnoloxías da Información e das Comunicacións en Redes Móbiles. 5029V01[Resumo]
Os sistemas de comunicación sen fíos de cuarta e quinta xeración (4G e 5G) utilizan unha capa física
(PHY) baseada en modulacións multiportadora para a transmisión de datos cun gran ancho de banda.
Este tipo de modulacións proporcionan unha alta eficiencia espectral á vez que permiten corrixir de
forma sinxela os efectos da canle radio.
Estes sistemas utilizan OFDMA como mecanismo para a repartición dos recursos radio dispoñibles
entre os diferentes usuarios. Este repartimento realízase asignando un subconxunto de subportadoras a
cada usuario nun instante de tempo determinado. Isto aporta unha gran flexibilidade ó sistema que lle
permite adaptarse tanto ós requisitos de calidade de servizo dos usuarios como ó estado da canle radio.
A capa de acceso ó medio (MAC) destes sistemas encárgase de configurar os diversos parámetros
proporcionados pola capa física OFDMA, ademais de xestionar os diversos fluxos de información de
cada usuario, transformando os paquetes de capas superiores en paquetes da capa física.
Neste traballo estúdase o deseño e implementación das capas MAC e PHY de sistemas de
comunicación 4G ademais da súa aplicabilidade en sistemas de transporte ferroviarios.
Por unha parte, abórdase o deseño e implementación en tempo real do estándar WiMAX. Estúdanse
os mecanismos necesarios para establecer comunicacións bidireccionais entre unha estación base e
múltiples dispositivos móbiles. Ademais, estúdase como realizar esta implementación nunha arquitectura
hardware baseada en DSPs e FPGAs, na que se implementan as capas MAC e PHY. Dado que esta
arquitectura ten uns recursos computacionais limitados, tamén se estudan as necesidades de cada módulo
do sistema para poder garantir o funcionamento en tempo real do sistema completo.
Por outra parte, tamén se estuda a aplicabilidade dos sistemas 4G a sistemas de transporte públicos.
Os sistemas de comunicacións e sinalización son unha parte vital para os sistemas de transporte
ferroviario e metro. As comunicacións sen fíos utilizadas por estes sistemas deben ser robustas e
proporcionar unha alta fiabilidade para permitir a supervisión, control e seguridade do tráfico ferroviario.
Para levar a cabo esta avaliación de viabilidade realízanse simulacións de redes de comunicacións
LTE en contornos de transporte ferroviarios, comprobando o cumprimento dos requisitos de fiabilidade
e seguridade. Realízanse diferentes simulacións do sistema de comunicacións para poder ser avaliadas e
seleccionar a configuración e arquitectura do sistema máis axeitada en función do escenario considerado.
Tamén se efectúan simulacións de redes baseadas en Wi-Fi, dado que é a solución máis utilizada nos
metros, para confrontar os resultados cos obtidos para LTE.
Para que os resultados das simulacións sexan realistas débense empregar modelos de propagación
radio axeitados. Nas simulacións utilízanse tanto modelos deterministas como modelos baseados nos
resultados de campañas de medida realizadas nestes escenarios.
Nas simulacións empréganse os diferentes fluxos de información destes escenarios para comprobar
que se cumpren os requisitos de calidade de servicio (QoS). Por exemplo, os fluxos críticos para o control
ferroviario, como European Train Control System (ETCS) ou Communication-Based Train Control (CBTC), necesitan unha alta fiabilidade e un retardo mínimo nas comunicacións para garantir o correcto
funcionamento do sistema.[Resumen]
Los sistemas de comunicación inalámbricos de cuarta y quinta generación (4G y 5G) utilizan una capa
física (PHY) basada en modulaciones multiportadora para la transmisión de datos con un gran ancho
de banda. Este tipo de modulaciones han demostrado tener una alta eficiencia espectral a la vez que
permiten corregir de forma sencilla los efectos del canal radio.
Estos sistemas utilizan OFDMA como mecanismo para el reparto de los recursos radio disponibles
entre los diferentes usuarios. Este reparto se realiza asignando un subconjunto de subportadoras a cada
usuario en un instante de tiempo determinado. Esto aporta una gran flexibilidad al sistema que le permite
adaptarse tanto a los requisitos de calidad de servicio de los usuarios como al estado del canal radio.
La capa de acceso al medio (MAC) de estos sistemas se encarga de configurar los diversos parámetros
proporcionados por la capa física OFDMA, además de gestionar los diversos flujos de información de
cada usuario, transformando los paquetes de capas superiores en paquetes de la capa física.
En este trabajo se estudia el diseño e implementación de las capas MAC y PHY de sistemas de
comunicación 4G además de su aplicabilidad en sistemas de transporte ferroviarios.
Por una parte, se aborda el diseño e implementación en tiempo real del estándar WiMAX. Se
estudian los mecanismos necesarios para establecer comunicaciones bidireccionales entre una estación
base y múltiples dispositivos móviles. Además, se estudia cómo realizar esta implementación en una
arquitectura hardware basada en DSPs y FPGAs, en la que se implementan las capas MAC y PHY. Dado
que esta arquitectura tiene unos recursos computacionales limitados, también se estudian las necesidades
de cada módulo del sistema para poder garantizar el funcionamiento en tiempo real del sistema completo.
Por otra parte, también se estudia la aplicabilidad de los sistemas 4G a sistemas de transporte
públicos. Los sistemas de comunicaciones y señalización son una parte vital para los sistemas de
transporte ferroviario y metro. Las comunicaciones inalámbricas utilizadas por estos sistemas deben ser
robustas y proporcionar una alta fiabilidad para permitir la supervisión, control y seguridad del tráfico
ferroviario.
Para llevar a cabo esta evaluación de viabilidad se realizan simulaciones de redes de comunicaciones
LTE en entornos de transporte ferroviarios, comprobando si se cumplen los requisitos de fiabilidad y
seguridad. Se realizan diferentes simulaciones del sistema de comunicaciones para poder ser evaluados y
seleccionar la configuración y arquitectura del sistema más adecuada en función del escenario planteado.
También se efectúan simulaciones de redes basadas en Wi-Fi, dado que es la solución más utilizada en
los metros, para comparar los resultados con los obtenidos para LTE.
Para que los resultados de las simulaciones sean realistas se deben utilizar modelos de propagación
radio apropiados. En las simulaciones se utilizan tanto modelos deterministas como modelos basados en
los resultados de campañas de medida realizadas en estos escenarios.
En las simulaciones se utilizan los diferentes flujos de información de estos escenarios para
comprobar que se cumplen sus requisitos de calidad de servicio. Por ejemplo, los flujos críticos para el control ferroviario, como European Train Control System (ETCS) o Communication-Based Train
Control (CBTC), necesitan una alta fiabilidad y un retardo bajo en las comunicaciones para garantizar el
correcto funcionamiento del sistema.[Abstract]
The fourth and fifth generation wireless communication systems (4G and 5G) use a physical layer (PHY)
based on multicarrier modulations for data transmission using high bandwidth. This type of modulations
has shown to provide high spectral efficiency while allowing low complexity radio channel equalization.
These systems use OFDMA as a mechanism for distributing the available radio resources among
different users. This allocation is done by assigning a subset of subcarriers to each user in a given instant
of time. This provides great flexibility to the system that allows it to adapt to both the quality of service
requirements of users and the radio channel state.
The media access layer (MAC) of these systems is in charge of configuring the multiple OFDMA
PHY layer parameters, in addition to managing the data flows of each user, transforming the higher layer
packets into PHY layer packets.
This work studies the design and implementation of MAC and PHY layers of 4G communication
systems as well as their applicability in rail transport systems.
On the one hand, the design and implementation in real time of the WiMAX standard is addressed.
The required mechanisms to establish bidirectional communications between a base station and several
mobile devices are also evaluated. Moreover, a MAC layer and PHY layer implementation is
presented, using a hardware architecture based in DSPs and FPGAs. Since this architecture has limited
computational resources, the requirements of each processing block of the system are also studied in
order to guarantee the real time operation of the complete system.
On the other hand, the applicability of 4G systems to public transportation systems is also studied.
Communications and signaling systems are a vital part of rail and metro transport systems. The
wireless communications used by these systems must be robust and provide high reliability to enable
the supervision, control and safety of rail traffic.
To carry out this feasibility assessment, LTE communications network simulations are performed in
rail transport environments to verify that reliability and safety requirements are met. Several simulations
are carried out in order to evaluate the system performance and select the most appropriate system
configuration in each case. Simulations of Wi-Fi based networks are also carried out, since it is the
most used solution in subways, to compare the results with those obtained for LTE.
To perform the simulations correctly, appropriate radio propagation models must be used. Both
deterministic models and models based on the results of measurement campaigns in these scenarios are
used in the simulations.
The simulations use the different information flows present in the railway transportation systems to
verify that its quality of service requirements are met. For example, critical flows for railway control,
such as the European Train Control System (ETCS) or Communication-Based Train Control (CBTC),
require high reliability and low delay communications to ensure the proper functioning of the system
"Performance Evaluation of Wi-Fi comparison with WiMAX Networks"
Wireless networking has become an important area of research in academic and
industry. The main objectives of this paper is to gain in-depth knowledge about
the Wi-Fi- WiMAX technology and how it works and understand the problems about
the WiFi- WiMAX technology in maintaining and deployment. The challenges in
wireless networks include issues like security, seamless handover, location and
emergency services, cooperation, and QoS.The performance of the WiMAX is better
than the Wi-Fi and also it provide the good response in the access. It's
evaluated the Quality of Service (Qos) in Wi-Fi compare with WiMAX and provides
the various kinds of security Mechanisms. Authentication to verify the identity
of the authorized communicating client stations. Confidentiality (Privacy) to
secure that the wirelessly conveyed information will remain private and
protected. Take necessary actions and configurations that are needed in order
to deploy Wi-Fi -WiMAX with increased levels of security and privacyComment:
WiMax - a critical view of the technology and its economics
University of the Witwatersrand
Faculty of Engineering and the Built Environment
School of Information and Electrical EngineeringMobile Broadband is now more of a necessity than a luxury, especially amongst the younger generation, irrespective of where they live. Mobile WiMax and LTE, the latest and fastest Mobile Broadband technologies, mark significant improvements over 3G networks because they use IP (Internet Protocol) end-to-end. To end-users, this means faster network speeds, better quality services, and increased coverage area. To the Network Operators, this means simplified network architectures, efficient use of resources, and improved security. In this report, the different issues and challenges related to deploying Mobile WiMax (802.16e or 802.16m) in rural South Africa, were identifed and explored. In this project, Atoll, SONAR, and Touch Point analysis tools were used to determine which Mobile Broadband technology is economically and technically suited for rural South Africa. It was found that LTE yields superior performance results than WiMax, which in turn yields superior performance results to all other existing 3G technologies. However it will take time for LTE to reach rural areas therefore WiMax can be considered as a solution to extend Broadband services to rural South Africa and thus assist in bridging the digital divide. Recommendations on how best to deploy Mobile WiMax are made based on observations made from the experimental work.MT201
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