Frequency-Selective Precoding for Uplink Transmissions
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Solution Overview
Problem
Current 3GPP specifications for LTE and 5G NR do not support frequency-selective precoding for uplink transmissions, leading to increased overhead and difficulties in channel estimation due to lack of limitations on precoder bundling size in the frequency domain.
Innovation Solution
Implementing frequency-selective precoding in both codebook-based and non-codebook-based UL transmissions by signaling subband TPMI and precoder bundling size from the network to the UE, allowing for differential signaling and predefined mappings to reduce overhead and ensure continuous channel response across PRBs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If frequency-selective precoding is supported by signaling precoder for each subband, then transmission precision is improved, but signaling overhead increases
Solution Approach 1:
The patent segments the frequency domain into subbands and introduces precoder bundling groups where the same precoder is applied across multiple subbands. This segmentation approach enables frequency-selective precoding while reducing signaling overhead by not requiring separate precoder indications for every subband, thus resolving the contradiction between transmission precision and signaling overhead.
Solution Approach 2:
The patent changes the parameter of precoder bundling size in the frequency domain, allowing flexible configuration of how many subbands share the same precoder. By adjusting this parameter, the system can balance between achieving sufficient frequency-selective precision and minimizing the signaling overhead required to indicate precoders.
2Adaptability or versatility
If precoder bundling size is not limited in frequency domain, then adaptability is improved, but channel estimation difficulty increases
Solution Approach 1:
The patent introduces dynamic precoder bundling size configuration where the network can adaptively set the bundling size based on channel conditions and requirements. This dynamic adjustment allows the system to maintain adaptability while ensuring that the bundling size remains manageable for channel estimation, preventing the channel response from being too discontinuous across bundled PRBs.
Data Source
AI summary
Various examples with respect to frequency-selective precoding for uplink (UL) transmissions in mobile communications are described. A processor of a user equipment (UE) receives signaling from a network node of a wireless network. The processor then performs a codebook-based UL transmission to the network node with frequency-selective precoding in a subband of a plurality of subbands according to the signaling received from the network. For non-codebook-based UL transmissions, the processor performs a non-codebook-based UL transmission of a beamformed sounding reference signal (SRS) to the network node by determining a precoder and performing frequency-selective precoding on the SRS using the precoder with a size of precoder bundling for the frequency-selective precoding in a frequency domain known by the network node.