NB-IoT M2M Communications in 5G Cellular Networks
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Universidad de Granada
DepartamentoUniversidad de Granada. Programa de Doctorado en Tecnologías de la Información y la Comunicación
Andrés-Maldonado, Pilar. NB-IoT M2M Communications in 5G Cellular Networks. Granada: Universidad de Granada, 2019. [http://hdl.handle.net/10481/56821]
SponsorshipTesis Univ. Granada.; National Research Project TIN2013-46223-P “Arquitectura para Redes Móviles 5G basada en Software Defined Networks" (“Architecture for 5G Mobile Networks based on Software Defined Networks") funded by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund.; National Research Project TEC2016-76795-C6-4-R “5G-City: Gestión Flexible de Servicios 5G Orientada a Soportar Situaciones Críticas Urbanas" (“5G-City: Adaptive Management of 5G Services to Support Critical Events in Cities") funded by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund.
The main objective of this thesis is to study the inclusion of massive MTC (mMTC) into cellular networks. More precisely, the use NB-IoT to support mMTC within the cellular networks. First, the signaling impact due to MTC in the current cellular network (i.e. 4G), is studied. To that end, a new architecture for the main control plane entity of the core is assumed. This new architecture is based on Network Functions Virtualization (NFV) and the studied entity is the Mobility Management Entity (MME). The analytical model is based on queuing theory. In the study, four possible designs are proposed and three traffic classes are considered: mobile broadband, mMTC, and low latency MTC. The evaluation is carried out considering the resources needed for dimensioning, the cost of the system, and the response time of each traffic class assumed. The results show the level of resource sharing and the target design traffic significantly impact the performance of each traffic class and the number of resources needed. Second, an analytical study of the NB-IoT coverage extension performance. To that end, the evaluation includes all available NB-IoT techniques applied to achieve the target of 164 dB Maximum Coupling Loss (MCL). The proposed analytical expressions are based on the Shannon theorem. The analysis includes the limitations due to realistic channel estimation. The results show the performance of the Signal to Noise Ratio (SNR) gain when doubling repetitions is significantly affected when assuming realistic channel estimation compared to ideal channel estimation. Consequently, NB-IoT devices in weak coverage condition will be challenging to reach even considering the novel NB-IoT techniques to extend coverage. Third, analytical and experimental NB-IoT performance evaluations are developed. The analytical evaluation is based on Markov chains and the experimental evaluation uses a controlled testbed. This testbed consists of commercial NB-IoT devices connected to a base station emulator. The NB-IoT performance evaluation is done in terms of the device's battery lifetime and latency. Using the testbed, the NB-IoT devices are studied empirically and later the proposed analytical model is experimentally validated. To that end, different traffic and coverage scenarios are considered. The validation results show the analytical model performs well compared to the empirical measurements under the same configuration in both cases. The results reach a maximum relative error of the battery lifetime estimation between the model and the measurements of 21% for an assumed Inter-Arrival Time (IAT) of 6 min. This relative error can be further reduced if larger IATs are considered or the model simplifications assumed are specified in the model. Additionally, the results demonstrate NB-IoT devices can achieve the targets of 10 years of battery lifetime or 10 seconds of uplink transmission latency for a large range of scenarios when the traffic profile has a large IAT, or the configuration of the radio resources do not require an extensive number of repetitions.