الفهرس 
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Abstract
Narrowband Internet of Things (NB-IoT) proves superiority to the other IoT networks from many different aspects. Where, it became as a complement part of the fifth-generation (5G) networks specifications. However, the increasing future demand for IoT applications requires that resource utilization be optimized to serve the maximum possible number of NB-IoT (User Equipment) UEs. Additionally, the relation between the NB-IoT spectral efficiency and the type of IoT traffic is not studied enough. Therefore, the achievement of traffic management over NB-IoT for efficient spectrum utilization is currently a new area for IoT 5G networks.
In this dissertation, we introduced a holistic vision that achieved two main goals. First, we improved the NB-IoT spectral efficiency to serve the increasing number of NB-IoT UEs. Second, we alleviated the burden of two issues; the signaling during each transmission request for periodic and aperiodic traffic such as Smart-Meters (SM) and emergency alarms and the queuing burden for periodic traffic. Additionally, this dissertation addresses the modeling issue of the NB-IoT from modeling ease, model scalability, and the impact of other upper layers of its protocol architecture.
Accordingly, this dissertation is divided into the three following phases. First, we model the protocol stack of the NB-IoT access network by using the state-machine modeling methodology by using the State-flow toolbox of the Simulink environment. Our model’s architecture is open-source and comprises all (Long Term Evolution) LTE and NB-IoT protocol layers. Therefore, our model is scalable and can be used for any future works. In the second phase, we evaluate the performance of the NB-IoT uplink scheduler in terms of the number of periodic NB-IoT versus four main Key Performance Indicators (KPIs): resources utilization, throughput, accessibility, and retain-ability. We apply our analysis to the periodic IoT traffic due to its domination in the IoT field. We assume that the access network model provides four different data rates for NB-IoT traffics. To ensure fairness, we divide the cell spectrum equally on the four data rates. Also, we assume ideal propagation without any transmission impairments and use round-robin scheduling.
The simulation results are verified according to the 3GPP standard and are validated with another trusted modeling technique. According to the above assumptions, the evaluation results depict that the NB-IoT single-tone data rate achieved the highest resources utilization and, at the same time, the highest channel holding time. However, the single-tone data rate’s low throughput value motivates us to improve the NB-IoT spectral efficiency. In the final phase, we introduce our holistic improvement approach.
The dissertation contains six chapters as follow:
Chapter One: Introduction
This chapter clarifies the following five points. First, the chapter summarizes the role of IoT in our life and defines the different between the main characteristics of human to human and IoT traffic profiles. Then, the chapter mentions the main new services provided by 5G and points out the main IoT network types in the 5G context, emphasizing that the NB-IoT is a complement part of standardized 5G-IoT networks. The third point defines the main characteristics of NB-IoT. The fourth point discusses the problem statements. Finally, the dissertation goals, novelties, and contributions are pointed out.
Chapter Two: Literature Review of NB-IoT Modelling and Adaptive MAC Techniques
This chapter presents the three following issues. First, the chapter introduces the main NB-IoT characteristics. Then, the previous work of NB-IoT from the following three aspects; spectral efficiency enhancement techniques, IoT traffic heterogeneity, and the NB-IoT modeling methodologies are reviewed, respectively.
Chapter Three: Proposed NB-IoT Modeling Methodology
This chapter has two sections. The first one describes our modeling methodology of the NB-IoT. The second section defines the Key Performance Indicators (KPIs) used to measure the uplink scheduler performance evaluation and MAC layer improvement.
Chapter Four: Proposed NB-IoT MAC Layer Enhancement
This chapter describes the proposed enhancement approach and applies the proposal on a case study of periodic and aperiodic traffic types for different IoT applications and services. Our improvement approach is divided into three main axes; periodic traffic handling, aperiodic traffic handling, and heterogeneous traffic management.
1) The periodic traffic handling exploited the periodicity nature of periodic applications such as smart meters. This handling was done by proposing a scheduling protocol after classifying the IoT traffic types and rearranging the transmission times of different smart meters utilities, and drawing a transmission schedule map for them to utilize the sparse time resources well.
2) The aperiodic traffic handling proposed the waiting list concept, which creates a waiting list for random access failed aperiodic fixed terminals, and then respond to this list just free channels are available.
3) The third axis proposed a traffic management system, which allocated the NB-IoT data rate according to the traffic type. This allocation scheme was proposed based on the performance evaluation results. Accordingly, we proposed to allocate the single-tone data rate for aperiodic emergency services due to the low probabilities of these events. And, we allocated the higher data rates for smart meters application, based on the payload of each cluster. Where, they are the most dominant periodic IoT applications.
Chapter Five: Simulation Results
This chapter analyzes and discusses the simulation conditions, environment, validation, performance evaluation results, and the proposed enhancement results, respectively. These results are evaluated in terms of the number of IoT terminals versus four KPIs, explained in chapter three.
Chapter Six: Conclusions and Future Work
Finally, chapter six represents the dissertation conclusions, and the future work suggested for enhancing the dissertation subject.