Interferência em comunicações Device-to-Device D2D

A constante necessidade de aumento da capacidade de rede para atender às crescentes demandas dos assinantes, leva a indústria de telecomunicações, apoiada pela comunidade científica, a criar novos paradigmas que suportem requisitos de taxa de dados binários elevados dentro da rede de acesso sem fio existente de forma eficiente e eficaz. Para responder a este desafio, a Comunicação Device-to-Device (D2D) em redes celulares é vista como uma solução promissora. Deste modo, a presente dissertação consiste na exploração do modelo de comunicação D2D (Device-to-Device), mediante o desenvolvimento de várias rotinas de comunicação D2D dentro de uma estrutura de rede celular LTE-A, usando simuladores já existentes, nomeadamente, simuladores de sistema em JAVA e simuladores de ligação em MatLab, afim de analisar o eventual aumento de capacidade da comunicação D2D para rede celular. Tipicamente, as comunicações em D2D permitem que os utilizadores localizados na proximidade, possam comunicar diretamente sem a intervenção da estação base (BS - Base Station). Essa comunicação pode permitir ritmos binários muito elevados, baixos atrasos e poupança de energia. Nesta dissertação alterou-se o simulador de sistema celular existente para incluir as comunicações D2D e as suas interferências, sendo apresentados os resultados obtidos. Os resultados obtidos por simulação confirmaram o que se esperava, nomeadamente, aumento dos ritmos binários nas comunicações D2D e redução do atraso.The continuing need to increase network capacity to meet growing subscriber demands leads the telecommunications industry, backed by the scientific community, to create new paradigms that support high binary data rate requirements within the existing wireless access network efficiently and effectively. To meet this challenge, Device-toDevice (D2D) Communication in cellular networks is seen as a promising solution. Thus, the present dissertation consists of the exploitation of the D2D (Device-toDevice) communication model, by developing several D2D communication routines within a LTE-A cellular network structure, using existing simulators, namely, simulator of system in JAVA and simulator of link in MatLab, in order to analyze the possible increase of capacity of D2D communication for cellular network. Typically, D2D communications allow users located in close proximity to communicate directly without the intervention of the base station (BS - Base Station). This communication can allow very high binary rates, low delays and energy savings. In this dissertation, the existing cellular system simulator was modified to include D2D communications and their interference, and the results obtained were presented. Simulation results have confirmed what was expected, namely, increasing bit rate with D2D communications and lower delays

An adaptive social-aware device-to-device communication mechanism for wireless networks

Device-to-Device (D2D) communication is an essential element in 5G networks, which enables users to communicate either directly without network assistance or with minimum signaling through a base station. For an effective D2D communication, related problems in mode and peer selection need to be addressed. In mode selection, the problem is how to guarantee selection always chooses the best available mode. In peer selection, the problem is how to select optimum peers among surrounding peers in terms of connection conditions and social relationships between peers. The main objectives of this research are to identify mode selection between devices and establishing a connection with the best D2D pair connection without privacy leakage. Multi-Attribute Decision Making and Social Choice theories are applied to achieve the objectives. Mode selection scheme is based on Received Signal Strength (RSS), delay and bandwidth attributes to choose and switch among the available modes intelligently based on the highest ranking. Then, the peering selection scheme is proposed using RSS, delay, bandwidth and power attribute to find an optimum peer with concerning social relationship, by evaluating trust level between peers and excluding the untrusted peers from ranking which will increase the optimum quality of D2D connection. The proposed schemes are validated and tested using MATLAB. Two main scenarios, namely crowded network and user speed were considered to evaluate the proposed mechanism with three existing approaches where the selection is based on a single attribute. The obtained results showed that the proposed mechanism outperforms other approaches in terms of delay, signal to noise ratio, delivery ratio and throughput with better performance up to 70%. The proposed mechanism provides a smooth switching between different modes and employs an automatic peering selection with trusted peers only. It can be applied in different types of network that serves the massive number of users with different movement speed of the user