6GNet 2022 – Tutorials
Title: Holographic Radio: A New Paradigm for Ultra-Massive MIMO
Abstarct: To enable a ubiquitous intelligent information network, the forthcoming sixth generation (6G) wireless communications are expected to provide revolutionary mobile connectivity and high-throughput data services through ultra-massive multiple input multiple output (MIMO). Widely-utilized phased arrays relying on costly components make the implementation of ultra-massive MIMO in practice become prohibitive from both cost and power consumption perspectives. The recent developed reconfigurable holographic surfaces (RHSs) composing of densely packing sub-wavelength metamaterial elements can achieve holographic beamforming without costly hardware components. By leveraging the holographic principle, the RHS serves as an ultra-thin and lightweight surface antenna integrated with the transceiver, thereby providing a promising alternative to phased arrays. In this tutorial, we will first provide a basic introduction of RHSs. We then introduce the unique features of RHSs which enables ultra-massive MIMO for both communication and sensing, in a comprehensive way. Related design, analysis, optimization, and signal processing techniques will be presented. Typical RHS-based applications for both wireless communications and radio-frequency sensing will be explored. The implementation issues along with our developed prototypes and experiments will also be discussed. Formalized analysis of several up-to-date challenges and technical details on system design will be provided for different applications.
Title: Ultra-Dense LEO Satellite-based Communication Systems: A Novel Modelling Technique
Abstract: We are witnessing an unprecedented boost in the space industry. The significant technological advances in the industry of low earth orbit (LEO) satellites have opened the door to a new realm of LEO-based applications. One key application is providing internet broadband services to people everywhere around the globe. This means that regions with limited or no connectivity, such as rural and remote regions, will be able to get stable connectivity. This can be considered a significant step towards resolving the digital divide problem that limits the opportunities available for communities in rural and remote regions because of the lack of internet access. The main driver to achieve such satellite-based global connectivity is deploying large numbers of LEO satellites at a set of altitudes, ranging from 300 km to 1500 km, to ensure that every part of the earth will be covered by at least one satellite at all times. Given the current status of the industry, where we have multiple competing companies launching various constellations with diverse altitudes and numbers of satellites, we can envision a set of spheres concentric with the earth with large numbers of LEO satellites distributed on the surfaces of each of these spheres. Due to the fundamental difference between these novel communication systems, specially the spatial distribution of the communication nodes, and the typical terrestrial communication networks, we need to think of creative techniques to enable mathematically analysing such communication systems. In this tutorial, we discuss a recently proposed mathematical framework that enables tractable analysis of LEO satellite-enabled communication systems while capturing the influence of satellites’ numbers and altitudes as well as the spatial distribution of earth stations. Firstly, we describe how this stochastic geometry-based framework is modelled and discuss its accuracy. Next, we provide a detailed example where this framework can be used for coverage analysis. We then introduce and discuss integrated space-aerial-terrestrial networks. Finally, we discuss how this framework can be used to study routing and end-to-end latency analysis in such networks. Realistic values from existing constellations, such as OneWeb and Starlink, are further used as case studies in this tutorial.
Title: Intelligent 6G networks: Use cases and network’s support for AI/ML
Abstract: Rapid growth in the number of connected wireless devices such as mobile phones, low-power IoT devices, connected vehicles, etc. will expand the scale of the next generation of mobile networks i.e. 5G advanced, and 6G. Moreover, the foreseen use cases like connected autonomous vehicles/robots/drones, smart homes, and cities, wireless automation of industrial networks, holographic communication for 6G networks will require ultra-low latency and ultra-high reliability. Existing and traditional algorithms are not feasible for the optimization, management, and orchestration of such networks to fulfill the requirements of the emerging use cases with high complexity, high dynamicity, and the massive amount of generated data by connected devices. Recently, artificial intelligence (AI) has been planned to be utilized as a new paradigm for the planning, optimization, management, and automation of next-generation of mobile networks. Machine learning (ML) as a subset of AI will be applied to develop intelligent connected devices and network infrastructures to address the demands of future use cases. The research, study, and development of AI/ML-enabled mobile networks have already been started in academia, industry, and standardization bodies such as 3GPP, O-RAN, ETSI, and ITU. However, the focus is the application of ML in 5G but their outcome will pave the way for 6G. This tutorial aims to give an insight into “AI/ML for 6G” which are the use cases where AI/ML can be applied in 6G optimization and management considering its vision, on one hand. On the other hand, networks’ support for AI/ML algorithms i.e. “6G for AI/ML” with respect to the standardization activities will also be explained.