Unsupervised learning for parametric optimization in wireless networks
This thesis studies parametric optimization in cellular and cell-free networks, exploring data-based and expert-based paradigms. Power allocation and power control, which adjust the transmit power to meet different fairness criteria such as max-min or max-product, are crucial tasks in wireless commu...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/671246 |
| Acceso en línea: | http://hdl.handle.net/10803/671246 |
| Access Level: | acceso abierto |
| Palabra clave: | Machine learning Neural networks Unsupervised learning Parametric optimization Power control Power allocation Cellular networks Cell-free networks Received signal strength indicator Regression analysis Adaptive learning Hilbert space Aprenentatge automàtic Xarxes neuronals Aprenentatge no supervisat L’assignació i el control de la potència Les xarxes cel.lulars Les xarxes cell-free Indicador d’intensitat de senyal rebuda Anàlisi de regressió Aprenentatge adaptatiu Espai de Hilbert Aprendizaje automático Redes neuronales Aprendizaje no supervisado La asignación y el control de la potencia Las redes celulares Las redes cell-free Indicador de intensidad de señal recibida Análisis de regresión Aprendizaje adaptativo Espacio de Hilbert 62 |
| Sumario: | This thesis studies parametric optimization in cellular and cell-free networks, exploring data-based and expert-based paradigms. Power allocation and power control, which adjust the transmit power to meet different fairness criteria such as max-min or max-product, are crucial tasks in wireless communications that fall into the parametric optimization category. The state-of-the-art approaches for power control and power allocation often demand huge computational costs and are not suitable for real-time applications. To address this issue, we develop a general-purpose unsupervised-learning approach for solving parametric optimizations; and extend the well-known fractional power control algorithm. In the data-based paradigm, we create an unsupervised learning framework that defines a custom neural network (NN), incorporating expert knowledge to the NN loss function to solve the power control and power allocation problems. In this approach, a feedforward NN is trained by repeatedly sampling the parameter space, but, rather than solving the associated optimization problem completely, a single step is taken along the gradient of the objective function. The resulting method is applicable for both convex and non-convex optimization problems. It offers two-to-three orders of magnitude speedup in the power control and power allocation problems compared to a convex solver—whenever appliable. In the expert-driven paradigm, we investigate the extension of fractional power control to cell-free networks. The resulting closed-form solution can be evaluated for uplink and downlink effortlessly and reaches an (almost) optimum solution in the uplink case. In both paradigms, we place a particular focus on large scale gains—the amount of attenuation experienced by the local-average received power. The slow-varying nature of the large-scale gains relaxes the need for a frequent update of the solutions in both the data-driven and expert-driven paradigms, enabling real-time application for both methods. |
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