近幾年無線寬頻網路崛起，寄望WiMAX可以取代最後一哩，雖然WiMAX有QoS的設計，但是對於Call Admission Control、Bandwidth Allocation、Scheduler並沒有實際定義，給予廠商彈性設計。本篇論文提出以機器學習的方式依據網路狀態動態配置頻寬，以符合實際頻寬需求。 由於BS在配置頻寬的時候並沒有SS佇列的訊息，使得BS無法配置適合的頻寬，達到較好的效能，尤其是有期限的rtPS封包最為明顯。在系統負載較高的環境下，容易導致封包遺失提升，吞吐量降低的情形發生。因此本研究提出了支持向量機的方式，收集大量Training Data，訓練成動態頻寬配置模組；以動態配置適合的頻寬給rtPS，使rtPS在負載高的環境下的封包遺失率降低，且延遲能夠維持一定水準。搭配適應性頻寬配置策略，在低負載的環境下可以保留少許頻寬給Non Real Time Traffic，在高負載環境下，先滿足Real Time Traffic為原則。模擬工具採用NS 2-2.29、長庚大學-資策會的WiMAX模組，以及台大林智仁老師開發的支持向量機函式庫libSVM。 / In recent years, the rise of wireless broadband access networks. Hope that WiMAX can solve the last mile problem. Although WiMAX has QoS design, but for call admission control, bandwidth allocation, scheduler are not defined in standard. In this paper, we proposed a machine learning approach dynamic bandwidth allocation based on network state. BS because of the bandwidth allocation at a time when there is no message of SS’s queue. Enables BS can not configure a more suitable bandwidth to achieve better performance. In particular, there is the deadline of rtPS packets. At the higher loading on the system environment, easily lead to packet loss raise, lower throughput situations happen. In this study, a support vector machine approach to collect a large number of training data. Training modules into a dynamic bandwidth allocation. We can dynamically allocate bandwidth to fit rtPS. Adaptive bandwidth allocation strategy, at the low loading environment can keep some bandwidth for non real time traffic. At a high loading environment must first meet the real time traffic. We use Network Simulator 2-2.29, CGU-III WiMAX module, libSVM library.

El presente proyecto de tesis consiste en desarrollar un análisis de los diferentes factores que intervienen en el diseño de una red de acceso empleando la tecnología WIMAX móvil. El lugar elegido para el despliegue de dicha red es Trujillo metropolitano debido a que presenta interesantes características de desarrollo que motivan al estudio de este mercado para futuras implementaciones. Como todo proyecto de Telecomunicaciones, se realiza un estudio previo de los principales operadores en dicha localidad para después fijar un mercado meta acorde con la realidad del mercado actual. A lo largo de la tesis se plantean varias inquietudes que finalmente serán resueltas en el capítulo más importante del presente trabajo, en el cual se presenta toda la ingeniería del proyecto aplicando los conceptos básicos de planificación de redes de Telecomunicaciones. En la parte final de la tesis se propone un interesante caso de negocio para un escenario como el de Trujillo metropolitano. / Tesis

En la presente tesis se plantea el diseño de una red WIMAX para el valle de Churín- Lima, para una operadora existente que quiere ofrecer sus servicios con dicha red. En este diseño se toma en cuenta no sólo a la población que habita el valle, sino también a aquellas que visitan con frecuencia el mismo. La tesis está estructurada de la siguiente manera: En el capítulo 1 se analiza la situación y problemática actual tanto en la provincia a la cual pertenece Churín, al valle en mención y porqué se desea insertar este diseño a Churín. En el capítulo 2 se muestra el marco teórico, donde se detallan los conceptos involucrados con la “Interoperabilidad mundial para acceso por microondas” (WIMAX) en su versión fija. En el capítulo 3 se realiza un análisis de demanda del mercado WIMAX para el valle de Churín, para de esta manera identificar a los potenciales clientes y los tipos de servicios a ofrecer. En el capítulo 4 se realiza la Ingeniería del Proyecto, donde se calcula la cantidad de estaciones Base a utilizar en la red, la topología de la misma, la red de transporte, la red de acceso, la infraestructura y equipos a emplear para la misma. Finalmente, en el capítulo 5 se evalúa el costo-beneficio de implementar esta red mediante el análisis del CAPEX Y OPEX, así como del VAN y el TIR. / Tesis

Este trabalho apresenta uma visão geral do modo de transmissão OFDM do padrão IEEE 802.16. O controle de acesso ao meio (MAC) e da camada física (PHY) são descritos em detalhes. Especialmente a estrutura do frame na camada (PHY). Além disso, as diferentes configurações da camada PHY com diferentes níveis de robustez são analisadas. Em seguida a simulação de um frame de dados com ADS (Advanced Design System) com todas as especificações da camada PHY são incluídas: Randomização, FEC, modulação adaptativa e IFFT/FFT. Um canal com multipercursos Rayleigh fading é implementada também. Finalmente são analisadas as curvas de espectro em freqüência e tempo, e a constelação no transmissor e receptor Downlink e Uplink, respectivamente. / This works presents a general overview of the mode of transmission OFDM standard IEEE 802.16. The medium access control (MAC) and physical layer (PHY) are described in detail, especially the structure of frame layer (PHY). Moreover, the different configurations PHY layers with different level strengths are analyzed. Then the simulation of a frame data with ADS (Advanced Design System) with all the specifications of PHY layer are included: Randomização, FEC, adaptive modulation and IFFT / FFT. A breaking multipath Rayleigh fading is implemented as well. In analyzes the curves of spectrum in frequency and time, and constellation in the transmitter and receiver Uplink and Downlink, respectively.

O padrão IEEE 802.16e é uma tecnologia emergente para redes de próxima geração com suporte à qualidade de serviço para usuários fixos e móveis. No contexto de aplicações móveis, a técnica OFDMA (Orthogonal Frequency Division Multiple Access) deve ser empregada para multiplexação de canais de rádio frequência, suportando a alocação simultânea do canal para múltiplos usuários. Porém, essa alocação, considerando a estrutura do quadro OFDMA, não é definida pelo padrão IEEE 802.16e. A maioria das pesquisas atuais sobre arquiteturas de escalonamento baseadas nessa técnica de multiplexação estão focadas na transmissão downlink ou consideram apenas parcialmente os aspectos decorrentes do emprego da técnica OFDMA. Sendo assim, neste trabalho é apresentada uma arquitetura de escalonamento hierárquica, com dois níveis, para transmissões uplink em redes IEEE 802.16e, baseadas em OFDMA. A arquitetura proposta aborda a divisão do subquadro uplink entre oportunidades de requisição de banda e oportunidades de transmissão de dados, no Nível 1, e a seleção das requisições de banda para atendimento, no Nível 2. A proposta considera, além da técnica de multiplexação do canal, as cinco classes de serviço previstas pelo padrão IEEE 802.16e e o mecanismo de alocação de banda definido para a tecnologia. Uma ferramenta de simulação foi desenvolvida para avaliar o desempenho da proposta, considerando os diferentes aspectos da arquitetura e comparando com trabalhos relacionados. A avaliação é realizada considerando métricas como atraso médio no atendimento de requisições, percentual de requisições descartadas e a utilização do quadro. / The IEEE 802.16e standard is an emerging next generation network technology, designed to provide guaranteed QoS to both fixed and mobile users. In the context of mobile users, OFDMA technique must be used to multiplex the radio frequency channel. This technique allows to allocate the channel to multiple users at the same time. However, details about this allocation, considering the OFDMA frame structure, are not defined by the IEEE 802.16e standard. In this context, most of the current researches found on literature focus on proposing scheduling architectures for downlink transmissions only. Furthermore, researches that consider uplink transmissions, typically consider OFDMA aspects only partially. Therefore, this work presents an hierarchical scheduling architecture designed for uplink transmissions. The proposed architecture is composed of two levels. In the Level 1 the architecture addresses the division of the uplink subframe in bandwidth request opportunities, and data transmission opportunities. Level 2 is used to select among the bandwidth request, those that will be served on the next uplink subframe. The proposal considers OFDMA multiplexing technique, the five classes of service defined for QoS provisioning, and the bandwidth allocation mechanism defined in IEEE 802.16e standard. In order to evaluate the behavior of the proposed architecture, a simulation tool was developed. The approach used for evaluation was to compare the performance of the proposed architecture with related works found in the literature. The performance evaluation considers metrics such as average delay for serving requests, requests discarded, and the overall frame utilization.

Este trabalho apresenta uma visão geral do modo de transmissão OFDM do padrão IEEE 802.16. O controle de acesso ao meio (MAC) e da camada física (PHY) são descritos em detalhes. Especialmente a estrutura do frame na camada (PHY). Além disso, as diferentes configurações da camada PHY com diferentes níveis de robustez são analisadas. Em seguida a simulação de um frame de dados com ADS (Advanced Design System) com todas as especificações da camada PHY são incluídas: Randomização, FEC, modulação adaptativa e IFFT/FFT. Um canal com multipercursos Rayleigh fading é implementada também. Finalmente são analisadas as curvas de espectro em freqüência e tempo, e a constelação no transmissor e receptor Downlink e Uplink, respectivamente. / This works presents a general overview of the mode of transmission OFDM standard IEEE 802.16. The medium access control (MAC) and physical layer (PHY) are described in detail, especially the structure of frame layer (PHY). Moreover, the different configurations PHY layers with different level strengths are analyzed. Then the simulation of a frame data with ADS (Advanced Design System) with all the specifications of PHY layer are included: Randomização, FEC, adaptive modulation and IFFT / FFT. A breaking multipath Rayleigh fading is implemented as well. In analyzes the curves of spectrum in frequency and time, and constellation in the transmitter and receiver Uplink and Downlink, respectively.

With the exploding increase of mobile users and the release of new wireless applications, the high bandwidth requirement has been taking as a main concern for the design and development of the wireless techniques. There is no doubt that broadband wireless access with the support of heterogeneous kinds of applications is the trend in the next generation wireless networks. As a promising broadband wireless access standard, IEEE 802.16 has attracted extensive attentions from both industry and academia due to its high data rate and the inherent media access control (MAC) mechanism, which takes the service differentiation and quality of service (QoS) provisioning into account. To achieve service differentiation and QoS satisfaction for heterogenous applications is a very complicated issue. It refers to many fields, such as connection admission control (CAC), congestion control, routing algorithm, MAC protocol, and scheduling scheme. Among these fields, packet scheduling plays one of the most important roles in fulfilling service differentiation and QoS provisioning. It decides the order of packet transmissions, and provides mechanisms for the resource allocation and multiplexing at the packet level to ensure that different types of applications meet their service requirements and the network maintains a high resource utilization. In this thesis, we focus on the packet scheduling for difficult types of services in IEEE 802.16 networks, where unicast and mulitcast scheduling are investigated. For unicast scheduling, two types of services are considered: non-real-time polling service (nrtPS) and best effort (BE) service. We propose a flexible and efficient resource allocation and scheduling framework for nrtPS applications to achieve a tradeoff between the delivery delay and resource utilization, where automatic repeat request (ARQ) mechanisms and the adaptive modulation and coding (AMC) technique are jointly considered. For BE service, considering the heterogeneity of subscriber stations (SSs) in IEEE 802.16 networks, we propose the weighted proportional fairness scheduling scheme to achieve the flexible scheduling and resource allocation among SSs based on their traffic demands/patterns. For multicast scheduling, a cooperative multicast scheduling is proposed to achieve high throughput and reliable transmission. By using the two-phase transmission model to exploit the spatial diversity gain in the multicast scenario, the proposed scheduling scheme can significantly improve the throughput not only for all multicast groups, but also for each group member. Analytical models are developed to investigate the performance of the proposed schemes in terms of some important performance measurements, such as throughput, resource utilization, and service probability. Extensive simulations are conducted to illustrate the efficient of the proposed schemes and the accuracy of the analytical models. The research work should provide meaningful guidelines for the system design and the selection of operational parameters, such as the number of TV channels supported by the network, the achieved video quality of each SS in the network, and the setting of weights for SSs under different BE traffic demands.

With the exploding increase of mobile users and the release of new wireless applications, the high bandwidth requirement has been taking as a main concern for the design and development of the wireless techniques. There is no doubt that broadband wireless access with the support of heterogeneous kinds of applications is the trend in the next generation wireless networks. As a promising broadband wireless access standard, IEEE 802.16 has attracted extensive attentions from both industry and academia due to its high data rate and the inherent media access control (MAC) mechanism, which takes the service differentiation and quality of service (QoS) provisioning into account. To achieve service differentiation and QoS satisfaction for heterogenous applications is a very complicated issue. It refers to many fields, such as connection admission control (CAC), congestion control, routing algorithm, MAC protocol, and scheduling scheme. Among these fields, packet scheduling plays one of the most important roles in fulfilling service differentiation and QoS provisioning. It decides the order of packet transmissions, and provides mechanisms for the resource allocation and multiplexing at the packet level to ensure that different types of applications meet their service requirements and the network maintains a high resource utilization. In this thesis, we focus on the packet scheduling for difficult types of services in IEEE 802.16 networks, where unicast and mulitcast scheduling are investigated. For unicast scheduling, two types of services are considered: non-real-time polling service (nrtPS) and best effort (BE) service. We propose a flexible and efficient resource allocation and scheduling framework for nrtPS applications to achieve a tradeoff between the delivery delay and resource utilization, where automatic repeat request (ARQ) mechanisms and the adaptive modulation and coding (AMC) technique are jointly considered. For BE service, considering the heterogeneity of subscriber stations (SSs) in IEEE 802.16 networks, we propose the weighted proportional fairness scheduling scheme to achieve the flexible scheduling and resource allocation among SSs based on their traffic demands/patterns. For multicast scheduling, a cooperative multicast scheduling is proposed to achieve high throughput and reliable transmission. By using the two-phase transmission model to exploit the spatial diversity gain in the multicast scenario, the proposed scheduling scheme can significantly improve the throughput not only for all multicast groups, but also for each group member. Analytical models are developed to investigate the performance of the proposed schemes in terms of some important performance measurements, such as throughput, resource utilization, and service probability. Extensive simulations are conducted to illustrate the efficient of the proposed schemes and the accuracy of the analytical models. The research work should provide meaningful guidelines for the system design and the selection of operational parameters, such as the number of TV channels supported by the network, the achieved video quality of each SS in the network, and the setting of weights for SSs under different BE traffic demands.

Since wireless network technology has advanced swiftly and dropped in price, it became a widely used networking option among numerous organizations and even single home users. In spite of their widespread usage by private sector, wireless networks are still undesired alternative for the governments due to security concerns. Although wireless networks possessed lots of proven and documented security flaws at first, with the latest researches and developments this condition ameliorated by the time and wireless networks became much more robust to various security attacks. In this thesis, a secure wireless network architecture that will allow exchange of unclassified information, using 802.11 (Wi-fi) and 802.16 (WIMAX), will be proposed that could be established by governments in case of emergency situations, namely natural disasters or wars, where cable infrastructure becomes unavailable.

M. Tech. Electrical Engineering. / Discusses raptor codes as fundamentally designed for erasure control coding technique, however, the overall objective of this dissertation is to examine their efficacy as a forward error correcting code as well as their spectral efficiency in the IEEE 802.16e-2005 physical layer. The specific objectives include: to analyse the error performance of raptor codes in mobile WiMAX ; to investigate the error performance of the various LDPC code classes defined in the mobile WiMAX standard ; to compare the performance of raptor codes and LDPC codes over the Additive White Gaussian Noise (AWGN) channel and to compare the spectral efficiency of raptor codes with that of the LDPC codes.