Event
【GIR Open Seminar】 Dr. Antti Tölli / University of Oulu (Finland)
| Date | 2024.10.31 (16：00 - 17：00) |
|---|---|
| Venue |
Lecture Room L0821, 2nd. Fl., Building 8, Koganei Campus, TUAT |
| Speaker | Dr. Antti Tölli |
| Affiliation | University of Oulu (Finland) |
| Title | "Exploiting Channel Sparsity: Multi-Antenna Codebooks in 5G NR Releases 15-18" ＜Abstract＞ The talk explores the design principles and evolution of multi-antenna codebooks in 3GPP 5G NR across Releases 15 to 18, focusing on downlink channel state information (CSI) feedback. The core objective of these codebooks is to optimize MIMO systems by exploiting channel sparsity in the angular, delay, and Doppler domains, thereby balancing feedback overhead with maintaining sufficient beamforming precision. In Release 15, initial codebooks were introduced with Type-I and Type-II designs, supporting up to 32 antenna ports. Type-I codebooks provide coarse, lower-resolution feedback especially suitable for single-user scenarios, while Type-II codebooks enable more detailed, higher-resolution feedback tailored for multi-user MIMO (MU-MIMO) operation. Release 16 introduced enhanced Type-II (E-Type-II) codebooks with frequency-domain compression, leveraging the sparsity in the delay domain to reduce feedback overhead without compromising beamforming accuracy. In Release 17, further enhanced Type-II (Fe-Type-II) codebooks were introduced, utilizing partial reciprocity in angle and delay domains, available even in FDD, by leveraging uplink SRS measurements to allow more efficient usage of CSI-RS resources. Furthermore, rudimentary support for multi-TRP joint transmission was introduced, enabling basic coordination between multiple TRPs. Finally, Release 18 introduced beam grouping and coherence extension, allowing the UE to provide feedback for both coherent and non-coherent beams, to improve control over multiple TRP transmissions. These features enhance joint transmission performance by improving interference management and beamforming accuracy. The hierarchical approach for large antenna arrays, supporting more than 32 antenna ports, is also emphasized for scalable feedback in massive MIMO systems. |
| Language | English |
| Intended for | Everyone is welcome to join. |
| Co-Organized by | Institute of Global Innovation Research ”LIFE SCIENCE” Umebayashi Team Excellent Leader Development for Super Smart Society by New Industry Creation and Diversity |
| Contact | Institute of Global Innovation Research, Institute of Engineering Prof. Kenta Umebayashi e-mail: ume_k ( at ) cc.tuat.ac.jp |
| Remarks | This seminar will only be held face-to-face. |
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