PDSCH and CSI-RS Multiplexing With Multiple DFTs
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Solution Overview
Problem
CP-OFDM performance degrades at high frequencies due to sensitivity to phase noise and high Peak-to-Average Power Ratio (PAPR), limiting cell coverage and increasing power consumption, while DFT-s-OFDM has restrictions in multiplexing with CSI-RS symbols.
Innovation Solution
Implementing DFT-s-OFDM-based Physical Downlink Shared Channel (PDSCH) multiplexing with CSI-RS symbols, using DFT configurations for resource block and element indication, and time domain generation for CSI-RS transmission, along with switching between DFT-s-OFDM and CP-OFDM transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CP-OFDM is used for downlink transmission, then spectral efficiency is improved, but phase noise sensitivity and PAPR increase causing performance degradation at high frequencies
Solution Approach 1:
The patent segments the downlink transmission into different components: uses DFT-s-OFDM for PDSCH transmission and CP-OFDM for CSI-RS transmission. This segmentation allows each component to use the waveform optimized for its specific function, resolving the contradiction between spectral efficiency and phase noise sensitivity.
Solution Approach 2:
The patent applies different waveform characteristics to different parts of the transmission system. DFT-s-OFDM with low PAPR is applied locally to PDSCH where power consumption and phase noise matter, while CP-OFDM with high spectral efficiency is applied locally to CSI-RS where channel state information acquisition is critical.
2Loss of energy
If DFT-s-OFDM is used for PDSCH transmission, then PAPR and power consumption are reduced, but multiplexing capability with CSI-RS symbols is restricted
Solution Approach 1:
The patent segments the transmission system to use DFT-s-OFDM for PDSCH and CP-OFDM for CSI-RS separately, then combines them in the time domain. This allows DFT-s-OFDM to benefit from low PAPR while maintaining multiplexing capability through structured resource allocation.
Solution Approach 2:
The patent resolves the multiplexing restriction by moving to the time domain dimension. Instead of trying to multiplex in frequency domain which is restricted for DFT-s-OFDM, the system multiplexes PDSCH and CSI-RS in different time slots or symbols, effectively using time as an additional dimension for resource allocation.
3Area of stationary object
If multiple DFTs are applied for CSI-RS transmission, then coverage and beam quality indication are enhanced, but system complexity increases
Solution Approach 1:
The patent uses parameter changes in DFT configuration (number of DFTs, DFT sizes, mapping indices) to control the trade-off between coverage enhancement and system complexity. By adjusting these parameters, the system can optimize CSI-RS coverage without unnecessarily increasing processing complexity.
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for CSI-RS enhancement. One apparatus includes a transceiver and a processor that receives a first configuration comprising a configuration of indices and a length of at least one first DFT for mapping on CSI-RS symbols, and/or a configuration of a number and a length of at least one second DFT for CSI-RS transmission. The processor receives a CSI-RS transmission and a PDSCH transmission during a symbol by applying multiple DFTs based on the first configuration. The processor generates a CSI report based on the received CSI-RS and transmits the generated CSI report to the network entity.