PDSCH CSI Measurement Using DMRS for Accurate Link Adaptation
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately measuring channel state information (CSI) for physical downlink shared channels (PDSCH) due to issues such as small bandwidth, difficulty in determining rank indicator (RI) and precoding matrix indicator (PMI), and gaps between CSI measured from CSI-RS and actual receiver CSI status, leading to inefficient open-loop link adaptation.
Innovation Solution
Implementing frequency hopping for PDSCH resource mapping and combining CSI-RS measurements with DMRS for PDSCH to enhance CSI measurement accuracy, using higher layer signaling to configure frequency hopping parameters and indicating DMRS time domain locations, and triggering CSI reports through unified or separate DCIs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CSI measurement is performed using only CSI-RS, then measurement process is simple, but measurement accuracy does not reflect actual receiver CSI status
Solution Approach 1:
The patent combines CSI-RS measurements with PDSCH DMRS measurements to determine CSI. The UE measures both CSI-RS for channel quality and PDSCH DMRS for actual received signal quality, then combines these measurements to determine CSI including CQI, PMI, and RI. This merging approach reflects actual receiver CSI status more accurately while maintaining manageable complexity through standardized measurement procedures.
2Measurement precision
If bandwidth for CSI measurement is small, then resource usage is reduced, but measurement accuracy deteriorates
Solution Approach 1:
The patent enables wideband CSI measurement by applying frequency hopping across multiple PDSCH transmissions. Instead of relying on wide bandwidth in a single transmission, the UE measures DMRS across multiple frequency-hopped PDSCH occasions, effectively synthesizing a wideband measurement from multiple narrowband transmissions. This dimensional transition from time-frequency space allows accurate wideband CSI with limited per-transmission bandwidth.
3Adaptability or versatility
If frequency hopping is applied for PDSCH, then wideband CSI measurement is enabled, but resource allocation complexity increases
Solution Approach 1:
The patent implements dynamic frequency hopping for PDSCH transmissions carrying DMRS for CSI measurement. The frequency hop pattern is configured through higher-layer parameters including hopping direction, hop size, and number of hops. This dynamic resource allocation allows the system to adaptively perform wideband CSI measurements by hopping across different frequency resources while maintaining flexible and manageable complexity through standardized configuration mechanisms.
Data Source
AI summary
Systems and methods provide a channel state information (CSI) measurement based on measuring a demodulation reference signal (DMRS) for a physical downlink shared channel (PDSCH) transmission. A user equipment (UE) triggers measuring of a CSI reference signal (CSI-RS) from a base station. The UE triggers measuring of a DMRS for a PDSCH transmission from the base station. The UE generates a CSI report to report the CSI measurement, based on both the CSI-RS and the DMRS for the PDSCH transmission. The UE may then send the CSI report to report the CSI measurement to the base station.