37 research outputs found

    Mobile and Wireless Communications

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    Mobile and Wireless Communications have been one of the major revolutions of the late twentieth century. We are witnessing a very fast growth in these technologies where mobile and wireless communications have become so ubiquitous in our society and indispensable for our daily lives. The relentless demand for higher data rates with better quality of services to comply with state-of-the art applications has revolutionized the wireless communication field and led to the emergence of new technologies such as Bluetooth, WiFi, Wimax, Ultra wideband, OFDMA. Moreover, the market tendency confirms that this revolution is not ready to stop in the foreseen future. Mobile and wireless communications applications cover diverse areas including entertainment, industrialist, biomedical, medicine, safety and security, and others, which definitely are improving our daily life. Wireless communication network is a multidisciplinary field addressing different aspects raging from theoretical analysis, system architecture design, and hardware and software implementations. While different new applications are requiring higher data rates and better quality of service and prolonging the mobile battery life, new development and advanced research studies and systems and circuits designs are necessary to keep pace with the market requirements. This book covers the most advanced research and development topics in mobile and wireless communication networks. It is divided into two parts with a total of thirty-four stand-alone chapters covering various areas of wireless communications of special topics including: physical layer and network layer, access methods and scheduling, techniques and technologies, antenna and amplifier design, integrated circuit design, applications and systems. These chapters present advanced novel and cutting-edge results and development related to wireless communication offering the readers the opportunity to enrich their knowledge in specific topics as well as to explore the whole field of rapidly emerging mobile and wireless networks. We hope that this book will be useful for students, researchers and practitioners in their research studies

    D13.2 Techniques and performance analysis on energy- and bandwidth-efficient communications and networking

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    Deliverable D13.2 del projecte europeu NEWCOM#The report presents the status of the research work of the various Joint Research Activities (JRA) in WP1.3 and the results that were developed up to the second year of the project. For each activity there is a description, an illustration of the adherence to and relevance with the identified fundamental open issues, a short presentation of the main results, and a roadmap for the future joint research. In the Annex, for each JRA, the main technical details on specific scientific activities are described in detail.Peer ReviewedPostprint (published version

    Convergence of packet communications over the evolved mobile networks; signal processing and protocol performance

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    In this thesis, the convergence of packet communications over the evolved mobile networks is studied. The Long Term Evolution (LTE) process is dominating the Third Generation Partnership Project (3GPP) in order to bring technologies to the markets in the spirit of continuous innovation. The global markets of mobile information services are growing towards the Mobile Information Society. The thesis begins with the principles and theories of the multiple-access transmission schemes, transmitter receiver techniques and signal processing algorithms. Next, packet communications and Internet protocols are referred from the IETF standards with the characteristics of mobile communications in the focus. The mobile network architecture and protocols bind together the evolved packet system of Internet communications to the radio access network technologies. Specifics of the traffic models are shortly visited for their statistical meaning in the radio performance analysis. Radio resource management algorithms and protocols, also procedures, are covered addressing their relevance for the system performance. Throughout these Chapters, the commonalities and differentiators of the WCDMA, WCDMA/HSPA and LTE are covered. The main outcome of the thesis is the performance analysis of the LTE technology beginning from the early discoveries to the analysis of various system features and finally converging to an extensive system analysis campaign. The system performance is analysed with the characteristics of voice over the Internet and best effort traffic of the Internet. These traffic classes represent the majority of the mobile traffic in the converged packet networks, and yet they are simple enough for a fair and generic analysis of technologies. The thesis consists of publications and inventions created by the author that proposed several improvements to the 3G technologies towards the LTE. In the system analysis, the LTE showed by the factor of at least 2.5 to 3 times higher system measures compared to the WCDMA/HSPA reference. The WCDMA/HSPA networks are currently available with over 400 million subscribers and showing increasing growth, in the meanwhile the first LTE roll-outs are scheduled to begin in 2010. Sophisticated 3G LTE mobile devices are expected to appear fluently for all consumer segments in the following years

    Developments of 5G Technology

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    This technology is the future of current LTE technology which would be a boost to the future of wireless and computer networks, as the speeds would be way higher than the current LTE networks, which will push the technology to a new level. This technology will make the radio channels to support data access speeds up to 10 Gb/s which will turn the bandwidth radio channels as WiFi. Comparing it with other LTE technology\u27s it has high speed and capacity, support interactive multimedia, voice, internet and its data rate is 1 Gbps which makes it faster than other LTE鈥檚 . This is much more effective than other technology鈥檚 due to its advanced billing interfaces. This paper provides detail explanation of 5G technology, its architecture, challenges, advantages and disadvantages, issues and ends with future of 5G technology

    Characterization and design of coherent optical OFDM transmission systems based on Hartley Transform

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    Nowadays, due to huge deployment of optical transport networks, a continuous increase towards higher data rates up to 100 Gb/s and beyond is observed. Furthermore, an evolution of the current optical networks is forecasted, acquiring new functionalities, e.g. elastic spectrum assignment for the optical signals. The target for these new challenges in transmission is to find techniques ready to deal with a growth of demand for bandwidth continuously asked by network operators, for whom the standard systems do not meet the new functionalities while higher rates are being set up. A solution for covering all of those needs is to adapt techniques capable to deal with such enormous data rates, and ensuring the same high efficiency for long distances and mitigate the optical impairments accumulated along the transmission path. Additionally, these transmission techniques are expected to provide some degree of flexibility, in order to enhance the network flexibility. A promising technology that can fully cope with those requires is the coherent optical orthogonal frequency division multiplexing (CO-OFDM). CO-OFDM provides several advantages, namely high sensitivity and spectral efficiency, simple integration and possibility to fully recover a signal in phase, amplitude and polarization. These systems are composed by digital signal processing (DSP) blocks that easily process data and can equalize and compensate the main impairments, providing high tolerance for dispersion effects. However, CO-OFDM systems are not free from drawbacks. Their high peak-to-average power ratio (PAPR) reduce their tolerance to nonlinearities. Furthermore, CO-OFDM systems are sensitive to any frequency shift and phase offset. Hence, a constant envelope optical OFDM (CE-OFDM) is proposed for significantly reducing the PAPR and solving high sensitivity to nonlinear impairments. It consists in a phase modulated discrete multi-tone signal, which is coherently detected at the receiver side. An alternative transform, the discrete Hartley transform, is proposed to speed up calculations in the DSP and eliminate the need to have a Hermitian symmetry. The optical CE-OFDM by its unique flexibility and rate scalability turns out as a great technology applicable to different configurations, ranging from access to core networks. In case of access solutions, several cases are investigated. First, the optical CE-OFDM is applied for radio access network signals delivery by means of a wavelength division multiplexing (WDM) overlay in deployed access architecture. A decomposed radio access network is deployed over an existing standard passive optical network (PON), capable to avoid interference and cross talks with access signals between network clients. The system exhibited narrow channel spacing, while reducing losses fed into the access equipment path. Next, a full duplex 10 Gb/s bidirectional PON transmission over a single wavelength with RSOA based ONU is investigated. The key point of that system is the upstream transmission, which is achieved re-modulating the phase of a downstream intensity modulated signal after proper saturation. The reported sensitivity performances show a power budget matching the PON standards and an OSNR easy to reach on non-amplified PON. Next, a flexible metropolitan area network of up to 100km with traffic add/drop using WDM is investigated. There the narrowing effect of the optical filters is studied. Finally, an elastic upgrade of the existing Telefonica model of the Spanish national core network is proposed. For that, the transceiver architecture is proposed to be operated featuring polarization multiplexing. Respect to the existing fixed grid, the flexible approach (enabled by the CE-OFDM transceiver) results into reduced bandwidth occupancy and low OSNR requirement.Hoy en d铆a, debido al gran despliegue de las redes de 贸pticas de transporte, se espera un aumento continuado hacia mayores velocidades de datos, hasta 100 Gb/s y m谩s all谩. Por otra parte, la evoluci贸n que se prev茅 para las redes 贸pticas actuales, incluye la adquisici贸n de nuevas funcionalidades, por ejemplo, la asignaci贸n del espectro de forma el谩stica para las se帽ales 贸pticas. Por tanto, el claro desaf铆o en cuanto a las tecnolog铆as de transmisi贸n es encontrar t茅cnicas preparadas para hacer frente a un crecimiento de la demanda de ancho de banda; demanda que continuamente se incrementa por parte de los operadores de red, para quienes los sistemas est谩ndar no se acaban de ajustar a las nuevas funcionalidades que esperan para la red. Una soluci贸n para cubrir todas estas necesidades es la adaptaci贸n de t茅cnicas capaces de hacer frente a estas velocidades de datos enormes, y garantizar el mismo nivel de eficiencia para las largas distancias y mitigar las deficiencias 贸pticas acumuladas a lo largo de la ruta de transmisi贸n. Adem谩s, se espera que estas t茅cnicas de transmisi贸n puedan proporcionar cierto grado de flexibilidad, a fin de mejorar y hacer m谩s eficiente la gesti贸n de la red. Una tecnolog铆a prometedora que puede hacer frente a estos requisitos es lo que se llama multiplexaci贸n por divisi贸n de frecuencias ortogonales, combinado con la detecci贸n 贸ptica coherente (CO-OFDM). CO-OFDM ofrece varias ventajas, entre otras: alta sensibilidad y eficiencia espectral y, sobre todo, la posibilidad de recuperar por completo de una se帽al en fase, la amplitud y la polarizaci贸n. Estos sistemas est谩n compuestos por bloques de procesado de se帽ales digitales (DSP) que permiten detectar los datos f谩cilmente as铆 como tambi茅n compensar las principales degradaciones, proporcionando alta tolerancia a los efectos de dispersi贸n. Sin embargo, los sistemas CO-OFDM no est谩n exentos de inconvenientes. Su alta relaci贸n de potencia de pico a potencia media (PAPR) reduce sensiblemente la tolerancia no linealidades. Por otra parte, los sistemas CO-OFDM son sensibles a cualquier cambio de frecuencia y desplazamiento de fase. Por tanto, se propone un sistema OFDM de envolvente constante (CE-OFDM) para reducir significativamente la PAPR y solucionar la alta sensibilidad a las degradaciones no lineales. Consiste en una se帽al OFDM modulada en fase, que se detecta coherentemente en el receptor. Una transformada alternativa, la transformada discreta de Hartley, se propone para acelerar los c谩lculos en el DSP. El sistema CE-OFDM por su flexibilidad y escalabilidad 煤nica, resulta una tecnolog铆a aplicable a diferentes escenarios, que van desde las redes de acceso hasta las redes troncales. En el caso de las soluciones de acceso, se investigan varios casos. En primer lugar, el CE-OFDM aplica para el desarrollo y soporte de datos de una red radio, reutilizando una red 贸ptica de acceso ya desplegada. A continuaci贸n, se investiga la transmisi贸n bidireccional d煤plex a 10 Gb / s sobre una sola longitud de onda empleando un RSOA a las unidades de usuario. El punto clave de este sistema es la transmisi贸n en sentido ascendente, que se consigue re-modulando la fase de una se帽al de intensidad modulada despu茅s de saturar de forma adecuada. A continuaci贸n, se estudia una red de 谩rea metropolitana flexible de hasta 100 km. Concretamente el efecto de concatenaci贸n de filtros 贸pticos es el objetivo de este estudio. Finalmente, se propone una actualizaci贸n el谩stica del modelo de Telef贸nica I+D para la red troncal espa帽ola. Por ello, se propone operar el CE-OFDM en multiplexaci贸n de polarizaci贸n. Los resultados muestran que esta combinaci贸n reduce sensiblemente el empleo de ancho de banda esto como los requisitos de los enlaces transmisi贸n, reduciendo tambi茅n los costes tanto de desarrollo como de operaci贸n y mantenimiento de la red.Avui dia, a causa del gran desplegament de les xarxes de 貌ptiques de transport, s'espera un augment continuat cap a majors velocitats de dades, fins a 100 Gb/s i m茅s enll脿. D'altra banda, l'evoluci贸 que es preveu per a les xarxes 貌ptiques actuals, inclou l'adquisici贸 de noves funcionalitats, per exemple, assignaci贸 de l'espectre de forma el脿stica per als senyals 貌ptics. Per tant, el clar desafiament pel que fa a les tecnologies de transmissi贸 茅s trobar t猫cniques preparades per fer front a un creixement de la demanda d'ample de banda; demanda que cont铆nuament es fa per part dels operadors de xarxa, per als qui els sistemes est脿ndard no s'acaben d'ajustar a les noves funcionalitats que esperen per a la xarxa. Una soluci贸 per a cobrir totes aquestes necessitats 茅s l'adaptaci贸 de t猫cniques capaces de fer front a aquestes velocitats de dades enormes, i garantir el mateix nivell d'efici猫ncia per a les llargues dist脿ncies i mitigar les defici猫ncies 貌ptiques acumulades al llarg de la ruta de transmissi贸. A m茅s, s'espera que aquestes t猫cniques de transmissi贸 puguin proporcionar cert grau de flexibilitat, per tal de millorar i tornar m茅s eficient la gesti贸 de la xarxa. Una tecnologia prometedora que pot fer front a aquests requisits 茅s el que s'anomena multiplexaci贸 per divisi贸 de freq眉猫ncies ortogonals, combinat amb la detecci贸 貌ptica coherent (CO-OFDM). CO-OFDM ofereix diversos avantatges, entre altres: alta sensibilitat i efici猫ncia espectral i, sobretot, la possibilitat de recuperar per complet d'una senyal en fase, l'amplitud i la polaritzaci贸. Aquests sistemes estan compostos per blocs de processament de senyals digitals (DSP) que permeten detectar les dades f脿cilment aix铆 com tamb茅 compensar les principals degradacions, proporcionant alta toler脿ncia pels efectes de dispersi贸. No obstant aix貌, els sistemes CO-OFDM no estan exempts d'inconvenients. La seva alta relaci贸 de pot猫ncia de pic a pot猫ncia mitjana (PAPR) redueix sensiblement la toler脿ncia a no linealitats. D'altra banda, els sistemes de CO-OFDM s贸n sensibles a qualsevol canvi de freq眉猫ncia i despla莽ament de fase. Per tant, es proposa un sistema OFDM d'envolvent constant (CE-OFDM) per a reduir significativament la PAPR i solucionar l'alta sensibilitat a les degradacions no lineals. Consisteix en un senyal OFDM modulat en fase, que es detecta coherentment en el receptor. Una transformada alternativa, la transformada discreta d'Hartley, es proposa accelerar els c脿lculs en el DSP. El sistema CE-OFDM per la seva flexibilitat i escalabilitat 煤nica, resulta una tecnologia aplicable a diferents escenaris, que van des de les xarxes d'acc茅s fins a les xarxes troncals. En el cas de les solucions d'acc茅s, s'investiguen diversos casos. En primer lloc, el CE-OFDM s'aplica per al desplegament i suport de dades d'una xarxa radio, reutilitzant una xarxa 貌ptica d'acc茅s ja desplegada. A continuaci贸, s'investiga la transmissi贸 bidireccional d煤plex a 10 Gb/s sobre una sola longitud d'ona emprant un RSOA a les unitats d'usuari. El punt clau d'aquest sistema 茅s la transmissi贸 en sentit ascendent, que s'aconsegueix re-modulant la fase d'un senyal d'intensitat modulada despr茅s de saturar-la de forma adequada. A continuaci贸, s'estudia una xarxa d'脿rea metropolitana flexible de fins a 100 km. Concretament l'efecte de concatenaci贸 de filtres 貌ptics 茅s l'objectiu d'aquest estudi. Finalment, es proposa una actualitzaci贸 el脿stica del model de Telef贸nica I+D per a la xarxa troncal espanyola. Per aix貌, es proposa operar el CE-OFDM en multiplexaci贸 de polaritzaci贸. Els resultats mostren que aquesta combinaci贸 redueix sensiblement l'ocupaci贸 d'ample de banda aix貌 com tamb茅 els requisits dels enlla莽os transmissi贸, reduint tamb茅 els costos tant de desplegament com d'operaci贸 i manteniment de la xarxa

    Modelling, Dimensioning and Optimization of 5G Communication Networks, Resources and Services

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    This reprint aims to collect state-of-the-art research contributions that address challenges in the emerging 5G networks design, dimensioning and optimization. Designing, dimensioning and optimization of communication networks resources and services have been an inseparable part of telecom network development. The latter must convey a large volume of traffic, providing service to traffic streams with highly differentiated requirements in terms of bit-rate and service time, required quality of service and quality of experience parameters. Such a communication infrastructure presents many important challenges, such as the study of necessary multi-layer cooperation, new protocols, performance evaluation of different network parts, low layer network design, network management and security issues, and new technologies in general, which will be discussed in this book
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