PRG Dithering for Shared-DMRS PDSCH Channel Estimation
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Solution Overview
Problem
In wireless communication systems, particularly in 5G NR, frequency division multiplexed physical downlink shared channels (PDSCHs) with shared demodulation reference signals (DMRS) face issues where certain UEs consistently experience higher channel estimation errors due to being allocated at the edge of resource blocks (RBs), leading to sub-optimal performance.
Innovation Solution
Implement PRG dithering techniques that distribute RBs corresponding to individual UEs uniformly across multiple PRGs using interleavers with depths coprime to the PRG size or cyclic RB shifts, ensuring more even distribution and reducing channel estimation errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UEs are allocated resource blocks at the edge of PRGs for frequency division multiplexing, then resource utilization efficiency is improved, but channel estimation error increases
Solution Approach 1:
The patent applies dynamic dithering to the RB index allocation, where the dither value is determined based on the PRG index and other parameters. This dynamic adjustment ensures that UEs are distributed across different RB indices within PRGs, preventing consistent edge allocations while maintaining high resource utilization. The dynamic nature of the dithering mechanism allows the system to adaptively balance between resource efficiency and channel estimation accuracy.
Solution Approach 2:
The patent modifies the RB index parameter by adding a dither value to the base RB index allocation. This parameter change transforms the static edge allocation into a dynamic distribution pattern, where the actual RB index becomes a function of multiple variables including PRG index, dither range, and modulation order. This parameter transformation resolves the contradiction by allowing edge-proximal allocations on average while providing variability that avoids consistent poor-channel positions.
2Ease of operation
If UEs are consistently allocated at edge RBs of PRGs, then resource allocation simplicity is improved, but performance reliability deteriorates
Solution Approach 1:
The patent implements preliminary dithering calculation during the resource allocation phase, where the dither value is computed and applied before the actual RB assignment. This preliminary action ensures that the performance reliability issue is addressed at the allocation stage itself, rather than requiring subsequent corrections or retransmissions. The dithering mechanism is built into the allocation algorithm, maintaining simplicity while improving reliability.
Solution Approach 2:
The dither value acts as an intermediary parameter between the simple edge allocation rule and the performance reliability requirement. Instead of directly allocating to edge RBs or avoiding them entirely, the dither mechanism introduces a controlled variability that mediates between these two extremes. This intermediary approach allows the system to maintain allocation simplicity while achieving performance reliability through statistical distribution across multiple PRGs and UEs.
Data Source
AI summary
A method for wireless communication at a network entity and related apparatus are provided. In the method, the network entity partitions a frequency range into a set of physical resource block groups (PRGs). Each PRG of the set of PRGs includes a number of resource blocks (RBs), and the number of RBs is greater than or equal to one. The network entity further assigns the RBs in one or more PRGs of the set of PRGs respectively to multiple user equipment (UEs). The RBs corresponding to a first UE of the multiple UEs occupy varied RB indices across the one or more PRGs. The network entity further transmits, to the first UE, a downlink transmission using the RBs corresponding to the first UE.