[Paper Review] Integration of Communication and Sensing in 6G: a Joint Industrial and Academic Perspective

Henk Wymeersch, Deep Shrestha+12 more|arXiv (Cornell University)|Jan 1, 2021

Indoor and Outdoor Localization TechnologiesEngineering57 references134 citations

TL;DR

The paper presents the Hexa-X vision for 6G, emphasizing tight integration of communication, localization, and sensing (JRC2LS) across frequencies up to THz, with use cases, required performance, and key technical enablers. It outlines hardware, waveform, and algorithmic approaches to achieve extreme localization and sensing performance from the outset of 6G.

ABSTRACT

6G will likely be the first generation of mobile communication that will feature tight integration of localization and sensing with communication functionalities. Among several worldwide initiatives, the Hexa-X flagship project stands out as it brings together 25 key players from adjacent industries and academia, and has among its explicit goals to research fundamentally new radio access technologies and high-resolution localization and sensing. Such features will not only enable novel use cases requiring extreme localization performance, but also provide a means to support and improve communication functionalities. This paper provides an overview of the Hexa-X vision alongside the envisioned use cases. To close the required performance gap of these use cases with respect to 5G, several technical enablers will be discussed, together with the associated research challenges for the coming years.

Motivation & Objective

• Motivate the need for extreme localization and sensing integration in 6G (JRC2LS) and outline Hexa-X use cases requiring high accuracy, low latency, and high reliability.
• Propose a holistic, start-to-end design approach where localization and sensing are integrated into channel modeling, hardware, waveform design, and protocols.
• Identify and discuss the key technical enablers (hardware, channels, waveforms, RIS, algorithms) and the main research challenges to close the gap with 5G.

Proposed method

• Survey and synthesize the Hexa-X vision and use cases for 6G localization and sensing.
• Analyze 5G localization capabilities and identify gaps to be closed by 6G integration.
• Propose a set of technical enablers (high-resolution processing, directionality, joint waveforms, intelligent infrastructure, and AI-driven algorithms) and discuss associated challenges.

Experimental results

Research questions

• RQ1 What extreme localization and sensing requirements are implied by 6G use cases in Hexa-X?
• RQ2 How can JRC2LS be integrated across hardware, signals, and protocols to meet stringent performance metrics?
• RQ3 What technical enablers are needed to achieve high-precision localization, sensing, and low-latency operation in 6G?
• RQ4 What are the primary challenges (hardware, channels, interoperability) in realizing 6G integrated sensing and communication?

Key findings

• 6G localization and sensing require 3D position, 3D orientation, and derivatives with extreme performance, latency, and integrity.
• 6G envisions JRC2LS with monostatic, bistatic, and multistatic modes and edge computing to support ultra-reliable sensing and communication.
• THz and mmWave bands, large MIMO, and wide bandwidths enable high-resolution angle, range, and Doppler processing for accurate sensing and mapping.
• Joint hardware, waveforms, and signal processing are essential to reuse communication signals for sensing and to enable dual-functional operations.
• RIS (reconfigurable intelligent surfaces) can aid localization and tracking when LoS is unavailable and enhance sensing information.
• A two-track algorithmic approach (model-based with geometric optics and data-driven AI methods) will handle high-dimensional channel information and hardware impairments.