Sub-band Precoded Reference Signals for NR Uplink
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Solution Overview
Problem
Existing wireless communication systems face limitations in network flexibility and increased signaling overhead due to codebook-based uplink schemes, particularly in supporting frequency selective precoding for New Radio (NR) systems.
Innovation Solution
The implementation of sub-band-specific reference signal precoding, where user equipment (UE) applies multiple precoding matrices to generate precoded reference signals transmitted over specific sub-bands, allowing base stations to perform wideband channel estimation and provide configuration feedback for improved communication parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If codebook-based uplink schemes are used to support frequency selective precoding, then network flexibility is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts the essential channel state information from wideband channel estimates and uses only the necessary components (sub-band channel estimates at anchor points) to determine precoding matrices. This removes unnecessary signaling while preserving the ability to support frequency selective precoding, thus reducing signaling overhead while maintaining network flexibility.
Solution Approach 2:
The patent segments the wideband channel estimation process into sub-band channel estimates at anchor points. By dividing the frequency band into segments and only requiring channel estimates at specific anchor points within each sub-band, the system reduces the amount of signaling overhead while maintaining the ability to perform frequency selective precoding across the entire band.
2Measurement precision
If wideband channel estimation is performed for each sub-band, then frequency selective precoding accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent performs preliminary wideband channel estimation to obtain channel estimates at anchor points across different sub-bands. These preliminary estimates are then used to determine precoding matrices without requiring additional real-time processing, thus achieving accurate frequency selective precoding while reducing processing complexity during actual transmission.
Solution Approach 2:
The patent uses channel estimates obtained at anchor points as representative copies for determining precoding matrices across entire sub-bands. Instead of performing complex processing on every frequency point, the system copies the channel estimation approach from anchor points to determine appropriate precoding for the entire sub-band, reducing processing complexity while maintaining accuracy.
Data Source
AI summary
The described techniques provide for the use of sub-band-specific reference signal precoding. A user equipment (UE) may apply multiple precoding matrices to a reference signal to generate a set of precoded reference signals and may transmit the precoded reference signals over respective sub-bands within a given reference signal resource set. In some cases, the UE may transmit a different set of precoded reference signals in each of multiple reference signal resource sets. Upon receiving the precoded reference signals, a base station may perform wideband channel estimation for each sub-band in the given reference signal resource set. The base station may compute an average spectral efficiency for each reference signal resource set and may transmit a report to the UE. The report may include one or more communication parameters for future communications between the UE and base station.