Current and Future Trends in 5G/B5G/6G

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Walid Saad, ECE Department, Virginia Tech, Blacksburg, USA

Professor, Fellow of IEEE

Title: Can Terahertz Communications Provide High-Rate Highly Reliable Low Latency Communications in 6G Networks?

Abstract: Communication at high-frequency terahertz (THz) bands is seen as a staple of the sixth generation (6G) of wireless cellular networks, due to the large amount of available bandwidth. However, 6G systems will have to support, not only high data rates, but also highly reliable communication links for emerging applications such as advanced wireless virtual reality (VR) systems. In particular, advanced wireless VR applications will impose new visual and haptic requirements that are directly linked to the quality-of-experience (QoE) of VR users. These QoE requirements can only be met by wireless 6G connectivity that offers high-rate and high-reliability low latency communications (HRLLC), unlike the low rates usually considered in vanilla 5G ultra-reliable low latency communication scenarios.  Guaranteeing HRLLC in THz-enabled 6G systems requires dealing with the uncertainty that is specific to the THz channel. Therefore, in this talk, after a brief overview on our vision of 6G systems, we will explore the potential of THz for meeting HRLLC requirements. In this regard, we first quantify the risk for an unreliable VR performance through a novel and rigorous characterization of the tail of the end-to-end (E2E) delay. Then, we perform a thorough analysis of the tail-value-at-risk (TVaR)  to concretely characterize the behavior of extreme wireless events crucial to the real-time VR experience. We use this analysis to derive system reliability for scenarios with guaranteed line-of-sight (LoS)  as a function of THz network parameters. We then present simulation results that show how abundant bandwidth and low molecular absorption are necessary to improve the reliability, although their effect remains secondary compared to the availability of LoS, which significantly affects the THz HRLLC performance. We conclude our talk with an overview on other key open problems in the realms of THz communications and 6G systems.

 

Halim Yanikomeroglu, ECE Department, Carleton University, Ottawa, ON, Canada

Professor, Fellow of IEEE, Fellow of Canadian Academy of Engineering, Fellow of Engineering Institute of Canada

Title: Wireless Access Architecture: The Next 20+ Years

Abstract: The very fundamental principles of digital and wireless communications reveal that the provision of ubiquitous super-connectivity in the global scale – i.e., beyond indoors, dense downtown or campus-type areas – is infeasible with the legacy terrestrial network architecture as this would require prohibitively expensive gross over-provisioning. The problem will only exacerbate with even more demanding use-cases of 2030s such as UAVs requiring connectivity (ex: delivery drones), thus the 3D super-connectivity.

The roots of today’s wireless access architecture (the terrestrial 4G & 5G cellular network) go back to 1940s. The access architecture has evolved substantially over the decades. However, rapid developments in a number of domains outside telecommunications, including those in aerospace and satellite industries as well as in artificial intelligence, will likely result in a disruptive transformation in the wireless access architecture in the next 20+ years. 

In this talk, an ultra-agile, dynamic, distributed, and partly-autonomous vertical heterogeneous network (VHetNet) architecture with very low earth orbit satellites (VLEOs), high-altitude platform station (HAPS) systems, and UAV-BSs (UxNB in 3GPP terminology) for almost-ubiquitous super-connectivity will be presented.

In the envisioned VHetNet architecture, the HAPS systems constitute arguably the most promising tier. For more information on HAPS systems, please refer to the below papers under review:

https://arxiv.org/abs/2007.15088

https://arxiv.org/abs/2007.08747

https://arxiv.org/abs/2009.02771

https://arxiv.org/abs/2006.09328

https://arxiv.org/abs/2009.09477

 

Vincent Wong, ECE Department, University of British Columbia, Vancouver, BC, Canada

Professor, Fellow of IEEE

Title: Throughput Optimization for Grant-Free Multiple Access with Multiagent Deep Reinforcement Learning

Abstract: Grant-free multiple access (GFMA) is a promising paradigm to efficiently support uplink access of Internet of Things (IoT) devices. In this talk, we present a deep reinforcement learning (DRL)-based pilot sequence selection scheme for GFMA systems to mitigate potential pilot sequence collisions. We formulate a pilot sequence selection problem for aggregate throughput maximization in GFMA systems with specific throughput constraints as a Markov decision process (MDP). By exploiting multiagent DRL, we train deep neural networks (DNNs) to learn near-optimal pilot sequence selection policies from the transition history of the underlying MDP without requiring information exchange between the users. While the training process takes advantage of global information, we leverage the technique of factorization to ensure that the policies learned by the DNNs can be executed in a distributed manner. Simulation results show that the proposed scheme can achieve an average aggregate throughput that is close to the optimum, and has a better performance than several heuristic algorithms. 

 

Mehdi Bennis, ECE Department, University of Oulu, Finland

Professor, IEEE Fellow

Abstract: This talk will break down the vision of wireless network edge intelligence at scale in terms of theoretical and algorithmic principles in addition to a number of applications in beyond 5G/6G.

 

Wei Yu, ECE Department, University of Toronto, Toronto, ON, Canada

Fellow of IEEE and a Fellow of Canadian Academy of Engineering

Title: Data-Driven Approaches to Massive MIMO System Design

Abstract: In this talk, I will illustrate how machine learning can be used to improve the design of wireless communication systems. In particular, we propose deep learning approaches to design the channel sensing and downlink precoding strategies for both the time-domain duplex (TDD) and the frequency-domain duplex (FDD) massive MIMO systems at the mmWave frequency. The first part of the talk considers the design of TDD system employing hybrid analog and digital beamforming. In the second part of the talk, we further show that deep learning can be used for efficient and distributed channel estimation, quantization, feedback, and downlink multiuser precoding for an FDD cellular system with rate-limited feedback. 

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11:45 PM-- 12:00 PM; Opening and Welcome, Mansour Naslcheraghi, Chair of IEEE YP Montreal

12:00 PM-- 12:30 PM; Talk: Walid Saad

12:30 PM -- 12:35 PM; Q&A: Walid Saad

12:35 PM-- 01:05 PM; Talk: Halim Yanikomeroglu

01:05 PM -- 01:10 PM; Q&A: Halim Yanikomeroglu

01:10 PM-- 01:40 PM; Talk: Vincent Wong

01:40 PM -- 01:45 PM; Q&A: Vincent Wong

01:45 PM-- 02:15 PM; Talk: Mehdi Bennis

02:15 PM -- 02:20 PM; Q&A: Mehdi Bennis

02:20 PM-- 02:50 PM; Talk: Wei Yu

02:50 PM -- 02:55 PM; Q&A: Wei Yu

02:55 PM -- 03:10 PM; Q&A with all speakers

 

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