Prototyping and Experimental Results for ISAC-based Channel Knowledge Map

TL;DR

This paper demonstrates an integrated sensing and communication system that constructs and utilizes a channel knowledge map (CKM) for environment-aware communication, enabling training-free beam alignment in mmWave systems.

Contribution

It presents a prototype system that combines ISAC with CKM construction and application, showing practical mutual benefits and real-world experimental validation.

Findings

ISAC can construct and update CKM during communication.

Pre-learned CKM enables training-free beam alignment.

Experimental results validate the system's effectiveness.

Abstract

Channel knowledge map (CKM) is a novel approach for achieving environment-aware communication and sensing. This paper presents an integrated sensing and communication (ISAC)-based CKM prototype system, demonstrating the mutualistic relationship between ISAC and CKM. The system consists of an ISAC base station (BS), a user equipment (UE), and a server. By using a shared orthogonal frequency division multiplexing (OFDM) waveform over the millimeter wave (mmWave) band, the ISAC BS is able to communicate with the UE while simultaneously sensing the environment and acquiring the UE's location. The prototype showcases the complete process of the construction and application of the ISAC-based CKM. For CKM construction phase, the BS stores the UE's channel feedback information in a database indexed by the UE's location, including beam indices and channel gain. For CKM application phase, the BS looks up the best beam index from the CKM based on the UE's location to achieve training-free mmWave beam alignment. The experimental results show that ISAC can be used to construct or update CKM while communicating with UEs, and the pre-learned CKM can assist ISAC for training-free beam alignment.