Gigantic MIMO Channel Characterization: Challenges and Enabling Solutions
Mengting Li, Zhiqiang Yuan, Yejian Lyu, Pekka Kyösti, Jianhua Zhang, Wei Fan
Abstract
The sixth-generation (6G) communication system will leverage the evolving multiple-input-multiple-output (MIMO) technology, referred to as gigantic MIMO. It is envisioned to accommodate arrays with over one thousand antennas for low and mid frequency bands, and with up to thousands of antennas for high frequency bands such as THz. With such a substantial number of antenna elements, the gigantic MIMO technology has the potential to unlock new use cases and applications with extreme requirements. Radio channel characterization plays a crucial role in the design, optimization, and performance evaluation of these radio systems, making it highly desirable for advancing the deployment of the gigantic MIMO technology. This article discusses key challenges and potential solutions for radio channel characterization of gigantic MIMO systems, including channel modeling approaches, experimental platform development i.e., channel sounder design, and radio channel parameter estimation. Further, a channel measurement campaign based on a virtual antenna array (containing 2400 antenna elements) and a corresponding ray tracing simulation are performed for a practical indoor scenario as examples to characterize a realistic gigantic MIMO channel.