Telecommunications Wireless Generations: Overview, Technological Differences, Evolutional Triggers, and the Future

This study expands on prior studies on wireless telecommunication generations by examining the technological differences and evolutional triggers that characterise each Generation (from 1G to 5G). Based on a systematic literature review approach, this study examines fifty (50) articles to enhance our understanding of wireless generation evolution. Specifically, this study analyses i) the triggers that necessitated the evolution of wireless telecommunication generations and ii) makes a case regarding why it is imperative to look beyond the fifth Generation (5G) network technologies. The authors propose areas for future research

Physical and Link Layer Implications in Vehicle Ad Hoc Networks

Vehicle Ad hoc Networks (V ANET) have been proposed to provide safety on the road and deliver road traffic information and route guidance to drivers along with commercial applications. However the challenges facing V ANET are numerous. Nodes move at high speeds, road side units and basestations are scarce, the topology is constrained by the road geometry and changes rapidly, and the number of nodes peaks suddenly in traffic jams. In this thesis we investigate the physical and link layers of V ANET and propose methods to achieve high data rates and high throughput. For the physical layer, we examine the use of Vertical BLAST (VB LAST) systems as they provide higher capacities than single antenna systems in rich fading environments. To study the applicability of VB LAST to VANET, a channel model was developed and verified using measurement data available in the literature. For no to medium line of sight, VBLAST systems provide high data rates. However the performance drops as the line of sight strength increases due to the correlation between the antennas. Moreover, the performance of VBLAST with training based channel estimation drops as the speed increases since the channel response changes rapidly. To update the channel state information matrix at the receiver, a channel tracking algorithm for flat fading channels was developed. The algorithm updates the channel matrix thus reducing the mean square error of the estimation and improving the bit error rate (BER). The analysis of VBLAST-OFDM systems showed they experience an error floor due to inter-carrier interference (lCI) which increases with speed, number of antennas transmitting and number of subcarriers used. The update algorithm was extended to VBLAST -OFDM systems and it showed improvements in BER performance but still experienced an error floor. An algorithm to equalise the ICI contribution of adjacent subcarriers was then developed and evaluated. The ICI equalisation algorithm reduces the error floor in BER as more subcarriers are equalised at the expense of more hardware complexity. The connectivity of V ANET was investigated and it was found that for single lane roads, car densities of 7 cars per communication range are sufficient to achieve high connectivity within the city whereas 12 cars per communication range are required for highways. Multilane roads require higher densities since cars tend to cluster in groups. Junctions and turns have lower connectivity than straight roads due to disconnections at the turns. Although higher densities improve the connectivity and, hence, the performance of the network layer, it leads to poor performance at the link layer. The IEEE 802.11 p MAC layer standard under development for V ANET uses a variant of Carrier Sense Multiple Access (CSMA). 802.11 protocols were analysed mathematically and via simulations and the results prove the saturation throughput of the basic access method drops as the number of nodes increases thus yielding very low throughput in congested areas. RTS/CTS access provides higher throughput but it applies only to unicast transmissions. To overcome the limitations of 802.11 protocols, we designed a protocol known as SOFT MAC which combines Space, Orthogonal Frequency and Time multiple access techniques. In SOFT MAC the road is divided into cells and each cell is allocated a unique group of subcarriers. Within a cell, nodes share the available subcarriers using a combination of TDMA and CSMA. The throughput analysis of SOFT MAC showed it has superior throughput compared to the basic access and similar to the RTS/CTS access of 802.11

Challenges Imposed by User's Mobility in Future HetNet: Offloading and Mobility Management

The users' mobility imposes challenges to mobility management and, the offloading process, which hinder the conventional heterogeneous networks (HetNets) in meeting the huge data traffic requirements of the future. In this thesis, a trio-connectivity (TC), which includes a control-plane (C-plane), a user-plane (U-plane) and an indication-plane (I-plane), is proposed to tackle these challenges. Especially, the I-plane is created as an indicator to help the user equipment (UE) identify and discover the small cells in the system prior to offloading her from the overloaded cells e.g. macro cells, to the cells with abundant resources e.g. small cells. In order to show the advantages of the proposed TC structure, a comparison between the TC and the dual-connectivity (DC) is presented in this thesis, in terms of uplink energy efficiency (ULEE) and energy consumption. Furthermore, the complexity of mobility management is addressed in this thesis as the HetNets will have to handle a large number of UEs and their frequent handoffs due to very dense small-footprint small cells. Considering an accurate mobility framework is essential not only to find the potential offloading to the small cells but also to show the mobility impact on the quality of service (QoS). This thesis presents a framework to model and derive the coverage of small cells, the cell sojourn time and the handoff rate in a multi-tier HetNet by taking into account the overlap coverage among the small cells. The results show the effects of a number of parameters, including the density and the transmit power of the small cells and the power control factor, on the system performance. They also show that the TC can outperform the DC in dense HetNets in terms of energy efficiency and energy consumption

Providing telecommunication to the tea plantations in Bangladesh

Analyzing all the existing telecommunication technologies in Bangladesh, discussing their merits and demerits, and choosing the most viable option in order to provide a network system to the tea planters for facilitating updating of necessary information of the tea estates to the head offices and vice versa

Contribución a la caracterización de los mecanismos de acceso y traspaso en sistemas móviles celulares basados en transmisión de paquetes

La estandarización del esquema de acceso radio para los futuros sistemas de telecomunicación está a punto de ser una realidad. En el calendario propuesto por ITU para llevar a cabo la elaboración del estándar, se prevé que las primeras versiones de las especificaciones técnicas puedan estar disponibles a principios del año 2000. Pero la llegada de la tercera generación, conocida bajo el concepto IMT-2000 dentro de ITU y como UMTS en el ámbito europeo, no estsupeditada únicamente a la incorporación del nuevo sistema de acceso radio, sino que existe una marcada tendencia de migración de los sistemas móviles actuales hacia la provisión de los diferentes servicios y prestaciones ambicionados en el sistema IMT-2000/UMTS.Por tanto, el sistema IMT-2000/UMTS se plantea como una convergencia de diferentes sistemas y nuevas tecnologías que, paulatinamente, van armonizando sus características para poder llegar a conseguir una única plataforma global de telecomunicaciones. Y una de las directrices seguidas en dicha convergencia es la adopción de las denominadas técnicas de transmisión en modo paquete en sustitución de las actuales soluciones basadas en conmutación de circuitos. Algunos de los argumentos esgrimidos a favor de la incorporación de mecanismos de transmisión en modo paquete son los siguientes:* La posibilidad de realizar un uso más eficiente de los recursos radio disponibles. La asignación fija durante el transcurso de toda una conexión puede resultar completamente ineficiente para servicios a ráfagas o con tasas de transmisión fluctuantes.* Mayor flexibilidad a la hora de integrar tráfico de diferente naturaleza, como por ejemplo, voz, datos, deñales de vídeo, etc.* La mayor imbricación de las tecnologías de la información (IT), orientadas a paquetes, en las tecnologías de telecomunicaciones.* La integración paulatina de las redes de acceso móviles a una plataforma

Transport Layer Optimizations for Heterogeneous Wireless Multimedia Networks

The explosive growth of the Internet during the last few years, has been propelled by the TCP/IP protocol suite and the best effort packet forwarding service. However, quality of service (QoS) is far from being a reality especially for multimedia services like video streaming and video conferencing. In the case of wireless and mobile networks, the problem becomes even worse due to the physics of the medium, resulting into further deterioration of the system performance. Goal of this dissertation is the systematic development of comprehensive models that jointly characterize the performance of transport protocols and media delivery in heterogeneous wireless networks. At the core of our novel methodology, is the use of analytical models for driving the design of media transport algorithms, so that the delivery of conversational and non-interactive multimedia data is enhanced in terms of throughput, delay, and jitter. More speciffically, we develop analytical models that characterize the throughput and goodput of the transmission control protocol (TCP) and the transmission friendly rate control (TFRC) protocol, when CBR and VBR multimedia workloads are considered. Subsequently, we enhance the transport protocol models with new parameters that capture the playback buffer performance and the expected video distortion at the receiver. In this way a complete end-to-end model for media streaming is obtained. This model is used as a basis for a new algorithm for rate-distortion optimized mode selection in video streaming appli- cations. As a next step, we extend the developed models for the aforementioned protocols, so that heterogeneous wireless networks can be accommodated. Subsequently, new algorithms are proposed in order to enhance the developed media streaming algorithms when heterogeneous wireless networks are also included. Finally, the aforementioned models and algorithms are extended for the case of concurrent multipath media transport over several hybrid wired/wireless links.Ph.D.Committee Chair: Vijay Madisetti; Committee Member: Raghupathy Sivakumar; Committee Member: Sudhakar Yalamanchili; Committee Member: Umakishore Ramachandran; Committee Member: Yucel Altunbasa

Enhancement of The IEEE 802.15.4 Standard By Energy Efficient Cluster Scheduling

The IEEE 802.15.4 network is gaining popularity due to its wide range of application in Industries and day to day life. Energy Conservation in IEEE 802.15.4 nodes is always a concern for the designers as the life time of a network depends mainly on minimizing the energy consumption in the nodes. In ZigBee cluster-tree network, the existing literature does not provide combined solution for co-channel interference and power efficient scheduling. In addition, the technique that prevents network collision has not been provided. Delay and reliability issues are not addressed in the QoS-aware routing. Congestion is one of the major challenges in IEEE 802.15.4 Network. This network also has issues in admitting real time flows. The aim of the present research is to overcome the issues mentioned above by designing Energy Efficient Cluster Scheduling and Interference Mitigation, QoS Aware Inter-Cluster Routing Protocol and Adaptive Data Rate Control for Clustered Architecture for IEEE 802.15.4 Networks. To overcome the issue of Energy efficiency and network collision energy efficient cluster scheduling and interference mitigation for IEEE 802.15.4 Network is proposed. It uses a time division cluster scheduling technique that offers energy efficiency in the cluster-tree network. In addition, an interference mitigation technique is demonstrated which detects and mitigates the channel interference based on packet-error detection and repeated channel-handoff command transmission. For the issues of delay and reliability in cluster network, QoS aware intercluster routing protocol for IEEE 802.15.4 Networks is proposed. It consists of some modules like reliability module, packet classifier, hello protocol module, routing service module. Using the Packet classifier, the packets are classified into the data and hello packets. The data packets are classified based on the priority. Neighbour table is constructed to maintain the information of neighbour nodes reliabilities by Hello protocol module. Moreover, routing table is built using the routing service module. The delay in the route is controlled by delay metrics, which is a sum of queuing delay and transmission delay. For the issues of congestion and admit real-time flows an Adaptive data rate control for clustered architecture in IEEE 802.15.4 Networks is proposed. A network device is designed to regulate its data rate adaptively using the feedback message i.e. Congestion Notification Field (CNF) in beacon frame received from the receiver side. The network device controls or changes its data rate based on CNF value. Along with this scalability is considered by modifying encoding parameters using Particle Swarm Optimization (PSO) to balance the target output rate for supporting high data rate. Simulation results show that the proposed techniques significantly reduce the energy consumption by 17% and the network collision, enhance the performance, mitigate the effect of congestion, and admit real-time flows

Wavelet-based multi-carrier code division multiple access systems

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Recent Advances in Wireless Communications and Networks

This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters