RADIO NETWORK PLANNING AND OPTIMIZATION IN MOBILE WiMAX (IEEE 802.16e)

The project is mainly about the radio network design in Worldwide interoperability for Microwave Access (WiMAX) system. Being an IP based, wireless broadband technology WiMAX (IEEE 802.16) is able to provide performance-wise like 802.11/Wi-Fi networks while at same time possess cellular network-like performance in terms of coverage and QOS (quality of service). Its acronym has meaning of "Worldwide Interoperability for Microwave Access (WiMAX). WiMAX is introduced by IEEE to handle metropolitan area. Fixed WiMAX do provide coverage up to 50 km while its variant, Mobile WiMAX can cover up to 5-15 km distance. This is in contrast to WiFi technology which covers wireless local area network with radius of 100m at most. WiMAX can operates on both licensed and non-licensed frequencies, providing a regulated environment and viable economic model for wireless carriers. WiMAX’s purpose is to verify interoperability wireless broadband radios between vendors. Testings of WiMAX equipments are done by WiMAX Forum, mainly to confirm interoperability. This is contrast to its 4G counterpart- the more recent Long Term Evolution (LTE) standard. LTE can be a parallel technology to WiMAX but LTE meant to provide controlled environment of Internet. LTE devices are hesitant to give free access while WiMAX is ready to serve metropolitan area unanimously. Residents of urban area or any densely populated area will have serious triple-play (voice, video, data) traffic congestion in terms of Internet connectivity when the physical link is in wired form. To elevate from congested to a much-less congested traffic, a wireless medium is proposed as an alternative to wired counterpart, that is WiMAX platform. WiMAX further divides into two category, Fixed WiMAX and Mobile WiMAX. For mobility advantages, Mobile WiMAX will be thouroughly discussed as the proposed solution for this problem. Ultimately, we will be able to verify performance of WiMAX network via simulator ArcMap running Cellular Expert interface, verify deployment of Base Station and verify optimized coverage pattern on the network

RADIO NETWORK PLANNING AND OPTIMIZATION IN MOBILE WiMAX (IEEE 802.16e)

The project is mainly about the radio network design in Worldwide interoperability for Microwave Access (WiMAX) system. Being an IP based, wireless broadband technology WiMAX (IEEE 802.16) is able to provide performance-wise like 802.11/Wi-Fi networks while at same time possess cellular network-like performance in terms of coverage and QOS (quality of service). Its acronym has meaning of "Worldwide Interoperability for Microwave Access (WiMAX). WiMAX is introduced by IEEE to handle metropolitan area. Fixed WiMAX do provide coverage up to 50 km while its variant, Mobile WiMAX can cover up to 5-15 km distance. This is in contrast to WiFi technology which covers wireless local area network with radius of 100m at most. WiMAX can operates on both licensed and non-licensed frequencies, providing a regulated environment and viable economic model for wireless carriers. WiMAX’s purpose is to verify interoperability wireless broadband radios between vendors. Testings of WiMAX equipments are done by WiMAX Forum, mainly to confirm interoperability. This is contrast to its 4G counterpart- the more recent Long Term Evolution (LTE) standard. LTE can be a parallel technology to WiMAX but LTE meant to provide controlled environment of Internet. LTE devices are hesitant to give free access while WiMAX is ready to serve metropolitan area unanimously. Residents of urban area or any densely populated area will have serious triple-play (voice, video, data) traffic congestion in terms of Internet connectivity when the physical link is in wired form. To elevate from congested to a much-less congested traffic, a wireless medium is proposed as an alternative to wired counterpart, that is WiMAX platform. WiMAX further divides into two category, Fixed WiMAX and Mobile WiMAX. For mobility advantages, Mobile WiMAX will be thouroughly discussed as the proposed solution for this problem. Ultimately, we will be able to verify performance of WiMAX network via simulator ArcMap running Cellular Expert interface, verify deployment of Base Station and verify optimized coverage pattern on the network

1 Joint Scheduling and Fast Cell Selection in OFDMA Wireless Networks

Abstract—In modern broadband cellular networks, the omni-directional antenna at each cell is replaced by 3 or 6 directional antennas, one in every sector. While every sector can run its own scheduling algorithm, bandwidth utilization can be significantly increased if a joint scheduler makes these decisions for all the sectors. This gives rise to a new problem, referred to as “joint scheduling, ” addressed in this paper for the first time. The problem is proven to be NP-hard, but we propose efficient algorithms with a worstcase performance guarantee for solving it. We then show that the proposed algorithms indeed substantially increase the network throughput. Index Terms—Cellular networks, 4G mobile communication, Optimal scheduling. I

Multilayer optimization in radio resource allocation for the packet transmission in wireless networks

Doutoramento em Engenharia ElectrotécnicaNa última década tem-se assistido a um crescimento exponencial das redes de comunicações sem fios, nomeadamente no que se refere a taxa de penetração do serviço prestado e na implementação de novas infra-estruturas em todo o globo. É ponto assente neste momento que esta tendência irá não só continuar como se fortalecer devido à convergência que é esperada entre as redes móveis sem fio e a disponibilização de serviços de banda larga para a rede Internet fixa, numa evolução para um paradigma de uma arquitectura integrada e baseada em serviços e aplicações IP. Por este motivo, as comunicações móveis sem fios irão ter um papel fundamental no desenvolvimento da sociedade de informação a médio e longo prazos. A estratégia seguida no projecto e implementação das redes móveis celulares da actual geração (2G e 3G) foi a da estratificação da sua arquitectura protocolar numa estrutura modular em camadas estanques, onde cada camada do modelo é responsável pela implementação de um conjunto de funcionalidades. Neste modelo a comunicação dá-se apenas entre camadas adjacentes através de primitivas de comunicação pré-estabelecidas. Este modelo de arquitectura resulta numa mais fácil implementação e introdução de novas funcionalidades na rede. Entretanto, o facto das camadas inferiores do modelo protocolar não utilizarem informação disponibilizada pelas camadas superiores, e vice-versa acarreta uma degradação no desempenho do sistema. Este paradigma é particularmente importante quando sistemas de antenas múltiplas são implementados (sistemas MIMO). Sistemas de antenas múltiplas introduzem um grau adicional de liberdade no que respeita a atribuição de recursos rádio: o domínio espacial. Contrariamente a atribuição de recursos no domínio do tempo e da frequência, no domínio espacial os recursos rádio mapeados no domínio espacial não podem ser assumidos como sendo completamente ortogonais, devido a interferência resultante do facto de vários terminais transmitirem no mesmo canal e/ou slots temporais mas em feixes espaciais diferentes. Sendo assim, a disponibilidade de informação relativa ao estado dos recursos rádio às camadas superiores do modelo protocolar é de fundamental importância na satisfação dos critérios de qualidade de serviço exigidos. Uma forma eficiente de gestão dos recursos rádio exige a implementação de algoritmos de agendamento de pacotes de baixo grau de complexidade, que definem os níveis de prioridade no acesso a esses recursos por base dos utilizadores com base na informação disponibilizada quer pelas camadas inferiores quer pelas camadas superiores do modelo. Este novo paradigma de comunicação, designado por cross-layer resulta na maximização da capacidade de transporte de dados por parte do canal rádio móvel, bem como a satisfação dos requisitos de qualidade de serviço derivados a partir da camada de aplicação do modelo. Na sua elaboração, procurou-se que o standard IEEE 802.16e, conhecido por Mobile WiMAX respeitasse as especificações associadas aos sistemas móveis celulares de quarta geração. A arquitectura escalonável, o baixo custo de implementação e as elevadas taxas de transmissão de dados resultam num processo de multiplexagem de dados e valores baixos no atraso decorrente da transmissão de pacotes, os quais são atributos fundamentais para a disponibilização de serviços de banda larga. Da mesma forma a comunicação orientada à comutação de pacotes, inenente na camada de acesso ao meio, é totalmente compatível com as exigências em termos da qualidade de serviço dessas aplicações. Sendo assim, o Mobile WiMAX parece satisfazer os requisitos exigentes das redes móveis de quarta geração. Nesta tese procede-se à investigação, projecto e implementação de algoritmos de encaminhamento de pacotes tendo em vista a eficiente gestão do conjunto de recursos rádio nos domínios do tempo, frequência e espacial das redes móveis celulares, tendo como caso prático as redes móveis celulares suportadas no standard IEEE802.16e. Os algoritmos propostos combinam métricas provenientes da camada física bem como os requisitos de qualidade de serviço das camadas superiores, de acordo com a arquitectura de redes baseadas no paradigma do cross-layer. O desempenho desses algoritmos é analisado a partir de simulações efectuadas por um simulador de sistema, numa plataforma que implementa as camadas física e de acesso ao meio do standard IEEE802.16e.In the last decade mobile wireless communications have witnessed an explosive growth in the user’s penetration rate and their widespread deployment around the globe. It is expected that this tendency will continue to increase with the convergence of fixed Internet wired networks with mobile ones and with the evolution to the full IP architecture paradigm. Therefore mobile wireless communications will be of paramount importance on the development of the information society of the near future. In particular a research topic of particular relevance in telecommunications nowadays is related to the design and implementation of mobile communication systems of 4th generation. 4G networks will be characterized by the support of multiple radio access technologies in a core network fully compliant with the Internet Protocol (all IP paradigm). Such networks will sustain the stringent quality of service (QoS) requirements and the expected high data rates from the type of multimedia applications to be available in the near future. The approach followed in the design and implementation of the mobile wireless networks of current generation (2G and 3G) has been the stratification of the architecture into a communication protocol model composed by a set of layers, in which each one encompasses some set of functionalities. In such protocol layered model, communications is only allowed between adjacent layers and through specific interface service points. This modular concept eases the implementation of new functionalities as the behaviour of each layer in the protocol stack is not affected by the others. However, the fact that lower layers in the protocol stack model do not utilize information available from upper layers, and vice versa, downgrades the performance achieved. This is particularly relevant if multiple antenna systems, in a MIMO (Multiple Input Multiple Output) configuration, are implemented. MIMO schemes introduce another degree of freedom for radio resource allocation: the space domain. Contrary to the time and frequency domains, radio resources mapped into the spatial domain cannot be assumed as completely orthogonal, due to the amount of interference resulting from users transmitting in the same frequency sub-channel and/or time slots but in different spatial beams. Therefore, the availability of information regarding the state of radio resources, from lower to upper layers, is of fundamental importance in the prosecution of the levels of QoS expected from those multimedia applications. In order to match applications requirements and the constraints of the mobile radio channel, in the last few years researches have proposed a new paradigm for the layered architecture for communications: the cross-layer design framework. In a general way, the cross-layer design paradigm refers to a protocol design in which the dependence between protocol layers is actively exploited, by breaking out the stringent rules which restrict the communication only between adjacent layers in the original reference model, and allowing direct interaction among different layers of the stack. An efficient management of the set of available radio resources demand for the implementation of efficient and low complexity packet schedulers which prioritize user’s transmissions according to inputs provided from lower as well as upper layers in the protocol stack, fully compliant with the cross-layer design paradigm. Specifically, efficiently designed packet schedulers for 4G networks should result in the maximization of the capacity available, through the consideration of the limitations imposed by the mobile radio channel and comply with the set of QoS requirements from the application layer. IEEE 802.16e standard, also named as Mobile WiMAX, seems to comply with the specifications of 4G mobile networks. The scalable architecture, low cost implementation and high data throughput, enable efficient data multiplexing and low data latency, which are attributes essential to enable broadband data services. Also, the connection oriented approach of Its medium access layer is fully compliant with the quality of service demands from such applications. Therefore, Mobile WiMAX seems to be a promising 4G mobile wireless networks candidate. In this thesis it is proposed the investigation, design and implementation of packet scheduling algorithms for the efficient management of the set of available radio resources, in time, frequency and spatial domains of the Mobile WiMAX networks. The proposed algorithms combine input metrics from physical layer and QoS requirements from upper layers, according to the crosslayer design paradigm. Proposed schedulers are evaluated by means of system level simulations, conducted in a system level simulation platform implementing the physical and medium access control layers of the IEEE802.16e standard