Navegando por Assunto "Terabit DSL"

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Acesso aberto (Open Access)
Acoplamento de modos guiados em cabos de pares trançados utilizando antenas com simetria radial no cenário terabit DSL
(Universidade Federal do Pará, 2020-03-26) SOUSA, Brenda Penedo Tavares de; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434
The development of data transmission standards and access technologies has always been linked to the need to supply high data rates. Thus, technologies already implemented, such as the DSL (Digital Subscriber Line) system that uses twisted pairs for transmission, have been adjusting to support this growing data demand. In DSL systems, the twisted pairs are used as a transmission line, using the transverse electromagnetic mode (TEM). However, the physical limitations of the twisted pair as a transmission line prevent the system from achieving higher rates, needed to support fifth generation (5G) applications. Recently, it was proposed to use other transmission modes in the twisted pair, the higher order guided modes, as an alternative for this structure to be able to support transmission rates of the order of Terabits per second, having been termed as the Terabit DSL technology (TDSL). However, one of the challenges for this implementation is the coupling of the guided modes in the twisted pair, since they are not widely explored in the context of the propagation of higher-order guided modes, as simpler waveguides, such as Sommerfeld and Goubau. In this scenario, this dissertation aims to evaluate the coupling of the radiated signal between an antenna with radial propagation and the twisted pair cable, analyzing the electromagnetic behavior of structures. Considering that the twisted pair cable does not have a closed analytical model for the behavior of higher order modes, which propagate along these structures, all the results were obtained from numerical simulations in the software HFSS (High Frequency Structure Simulator).These results are in terms of the scattering parameter of the antenna and the electromagnetic field in the cable, making it possible to evaluate the coupling efficiency, the signal guidance and to predict the transmission rate available to users. The results obtained showed that the coupling between the antenna and the unshielded twisted pair cable reached levels of up to 83.83 % at frequencies of 0.15 THz, demonstrating a high coupling efficiency when compared to simpler scenarios in the literature, reaching levels on average 67 %. It was found that the use of these cables for data transmission is effective, managing to deliver rates of up to 1.737 Tbps in cables of up to 10 meters, while the rate forecasts for the TDSL scenario that consider the 100 % coupling reach levels of 2.013 Tbps.
Acesso aberto (Open Access)
Avaliação de modos guiados em cabos de cobre para transmissão de dados em terabit por segundo
(Universidade Federal do Pará, 2020-03-27) SOUZA, Daynara Dias; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434
Copper-based technologies have used twisted pair and coaxial cables as transmission lines, exploring TEM (Transverse Electromagnetic) mode to transmit data. In twisted pair technology, to ensure higher rates, it is necessary to increase the band frequencies, which also implies an increase in attenuation over the TEM mode, with a consequent limit on the link data rate. Applications for the latest generation (5G) systems require rates in the order of tens Gbps (Gigabit per second), practically impossible to meet due to their attenuation, even considering short links. In this context, to give a new breath to twisted pair cables, it was proposed to use them as waveguides, i.e., exploring their higher-order modes for transmission, in a system called Terabit DSL (Digital Subscriber Line). Such modes are of the TE (Transverse Electric) or TM (Transverse Magnetic) types, and arise when the wavelengths, associated to the operating frequencies, are of the same order or smaller than the cross-sectional dimensions of the twisted pair cable. A similar fact applies to coaxial cables. When using these modes, it is estimated transmission rates in the order of Tbps (Terabit per second) to be achieved on twisted pair cables. This enables, for example, to have twisted pair and coaxial cables as viable alternatives to the transport network in the future 5G system. Such predictions assume that the model based on the guided mode on a single bare conducting wire, known as the Sommerfeld model, describes the attenuation of the higher-order guided modes in a twisted pair. However, this model does not adequately describe twisted pair cables, given that its physical structure is much more complex. Therefore, a more accurate study on the characteristics of the higher-order modes present in twisted pair and coaxial cables is needed, aiming at predictions in complete agreement with the real structure and electromagnetic propagation through them. This work investigates the propagation of several guided modes in twisted pair and coaxial cables, from numerical simulations in the HFSS (High Frequency Structure Simulator) software, considering real constructive characteristics. Based on the results obtained, the aggregate data rate of each cable used as a waveguide was determined. The results obtained indicate that data rates of more than 1.7 Tbps in just one twisted pair can be reached for 10 meters in length, up to 6.1 Tbps in one cable with four twisted pairs and approximately 5.6 Tbps in one coaxial cable.