Multisource power splitting energy harvesting relaying network in half-duplex system over block Rayleigh fading channel: System performance analysis

Energy harvesting and information transferring simultaneously by radio frequency (RF) is considered as the novel solution for green-energy wireless communications. From that point of view, the system performance (SP) analysis of multisource power splitting (PS) energy harvesting (EH) relaying network (RN) over block Rayleigh-fading channels is presented and investigated. We investigate the system in both delay-tolerant transmission (DTT), and delay-limited transmission (DLT) modes and devices work in the half-duplex (HD) system. In this model system, the closed-form (CF) expressions for the outage probability (OP), system throughput (ST) in DLT mode and for ergodic capacity (EC) for DTT mode are analyzed and derived, respectively. Furthermore, CF expression for the symbol errors ratio (SER) is demonstrated. Then, the optimal PS factor is investigated. Finally, a Monte Carlo simulation is used for validating the analytical expressions concerning with all system parameters (SP).Web of Science81art. no. 6

Towards a network management solution for vehicular delay-tolerant networks

Vehicular networks appeared as a new communication solution where vehicles act as a communication infrastructure, providing data communications through vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I) communications. Vehicular Delay-Tolerant Networks (VDTNs) are a new disruptive network architecture assuming delay tolerant networking paradigm where there are no end-to-end connectivity. In this case the incial node transmits the data to a closed node, the data will be carried by vehicles, hop to hop until the destination. This dissertation focuses on a proposal of a network management solution, based standard protocol Simple Network Management Protocol (SNMP) to VDTN networks. The developed solution allows control a VDTN netowork through a Network Management System (NMS) with the objective to detect and, if it’s possible, anticipate, possible errors on network. The research methodology used was the prototyping. So, it was built a network management module to the laboratorial prototype, called VDTN@Lab. The system built include a MIB (Management Information Base) placed in all vehicular network nodes. The solution was built, demonstrated, validated and evaluated their performance, being ready for use.As redes veiculares foram desenhadas para permitir que os veículos possam transportar dados criando assim um novo tipo de redes, caracterizando-se por dois tipos de comunicação: comunicações veículo-para-veículo (V2V) ou comunicações veículo-parainfra-estrutura (V2I). Redes veiculares intermitentes (do Inglês Vehicular Delay-Tolerant Networks - VDTNs) surgiram como uma nova arquitectura de rede de dados onde os veículos são utilizados como infra-estruturas de comunicação. As VDTNs caracterizam-se por serem redes veiculares baseadas no paradigma de comunicações intermitentes. Nas redes VDTN não existe uma ligação permanente extremo a extremo entre o emissor e o receptor. Neste caso, o nó inicial transmite os dados para um nó que esteja junto dele e assim sucessivamente, os dados vão sendo transportados pelos veículos, salto a salto até ao destinatário final. Esta dissertação centra-se na proposta de uma solução de gestão de rede, baseada no protocolo estandardizado Simple Network Management Protocol (SNMP) para redes VDTN. A solução construída permite controlar uma rede VDTN através de um sistema de gestão de rede (do Inglês Network Management System - NMS) com o objectivo de detectar e, se possível antecipar, possíveis erros na rede. A metodologia de investigação utilizada foi a prototipagem. Assim, foi construído um módulo de gestão de redes para o protótipo laboratorial, chamado VDTN@Lab. O sistema construído inclui uma MIB (Management Information Base) que é colocada em todos os nós de uma rede veicular, tanto fixos como móveis. A solução foi construída, demonstrada, validade e avaliado o seu desempenho, estando assim pronta para ser utilizada

Upgrading SIM–OFDM Using a Threshold for Correct Operation with Analytical Proofs

A new upgrade to the SIM–OFDM is suggested to solve a critical problem that crashes the system even over noiseless channel. This problem is the interference of the zeros at the IFFT output with the BOOK\u27s zeros that confuses the receiver during demodulation which leads to BER accumulation. The suggested solution is to use a threshold to differentiate the data carried by the BOOK from the IFFT\u27s symbols. The new system is called Threshold SIM–OFDM (TSIM–OFDM). The mathematical analysis of TSIM–OFDM proves it operates normally and meets the theoretical bounds. The TSIM–OFDM preserves the probability of 1 equal to 1/2. This preservation comes from the direct connection of the ON/OFF switching bits to the subcarrier which overrides the majority condition. This new switching technique simplifies the system operation resulting in higher transmission speed and increased spectral and power efficiency. A simple approach to derive the BER for the SIM–OFDM is presented which proves that the SIM–OFDM will never reach zero BER level unlike the TSIM–OFDM. The simulation results show that the TSIM–OFDM BER reaches zero level and the output power is almost half of the OFDM. Adding the threshold will increase the transmitted power slightly and tends to decrease with the increase of IFFT length

Self organising cloud cells: a resource efficient network densification strategy

Network densification is envisioned as the key enabler for 2020 vision that requires cellular systems to grow in capacity by hundreds of times to cope with unprecedented traffic growth trends being witnessed since advent of broadband on the move. However, increased energy consumption and complex mobility management associated with network densifications remain as the two main challenges to be addressed before further network densification can be exploited on a wide scale. In the wake of these challenges, this paper proposes and evaluates a novel dense network deployment strategy for increasing the capacity of future cellular systems without sacrificing energy efficiency and compromising mobility performance. Our deployment architecture consists of smart small cells, called cloud nodes, which provide data coverage to individual users on a demand bases while taking into account the spatial and temporal dynamics of user mobility and traffic. The decision to activate the cloud nodes, such that certain performance objectives at system level are targeted, is carried out by the overlaying macrocell based on a fuzzy-logic framework. We also compare the proposed architecture with conventional macrocell only deployment and pure microcell-based dense deployment in terms of blocking probability, handover probability and energy efficiency and discuss and quantify the trade-offs therein