CSI Reporting via Segmented Antenna Port Groups
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Solution Overview
Problem
In wireless communication systems, existing methods for reporting channel state information (CSI) are inefficient, particularly in multi-node systems with distributed antenna ports, where time variance of the downlink channel poses challenges in accurately conveying CSI.
Innovation Solution
A method for reporting CSI by a terminal, involving the reception of a reference signal (RS) configuration, calculation of CSI, and reporting it to a serving cell, where the CSI includes a precoding matrix for RS transmission, which can be a subset of a codebook for data transmission, and the codebook is represented by a Kronecker product of vertical and horizontal antenna groups, with candidate matrices selected based on time variance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CSI reporting is performed in multi-node systems with distributed antenna ports, then channel state information can be obtained for cooperative communication, but time variance of the downlink channel reduces the accuracy of CSI reporting
Solution Approach 1:
The antenna ports are divided into multiple antenna port groups, where each group contains a subset of the total antenna ports. The terminal performs channel measurement separately for each antenna port group using reference signals, and reports CSI for each group individually. This segmentation allows the system to handle time variance more effectively by focusing measurements on smaller, more stable subsets of antennas, thereby improving overall CSI reporting accuracy in dynamic channel conditions.
2Loss of information
If reference signals are transmitted through all Nt antenna ports, then complete channel information can be measured, but signaling overhead and processing complexity increase
Solution Approach 1:
Instead of transmitting reference signals for all Nt antenna ports simultaneously, the system segments the antenna ports into multiple groups and transmits reference signals for each group separately. This reduces the signaling overhead and processing complexity at any given time while still enabling complete channel information measurement across all antenna ports through the aggregated measurements from different groups.
Solution Approach 2:
The terminal measures channel information for a subset of antenna ports (one group at a time) rather than all antenna ports simultaneously. This partial action approach reduces the immediate processing burden and signaling requirements while maintaining the capability to obtain complete channel information by sequentially measuring each antenna port group.
Data Source
AI summary
A method for reporting a channel state of a downlink channel transmitted through two-dimensionally arranged Nt number of antenna ports, according to one embodiment of the present disclosure, is performed by a terminal, and the method comprises the steps of: receiving a reference signal (RS) configuration for measuring a channel for the two-dimensionally arranged Nt number of antenna ports, wherein the RS is code division multiplexed (CDM) and is transmitted through the Nt number of antenna ports; and receiving the RS by using the received RS configuration, and calculating channel state information on a downlink channel so as to report the channel state information to a serving cell, wherein the reported channel state information includes a precoding matrix for the transmission of the RS, and the precoding matrix for the transmission of the RS can be subset of a codebook for a precoding matrix for the data transmission of the Nt number of antenna ports.