Beam-Based SUL Selection for Accurate 5G NR Random Access
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Solution Overview
Problem
Existing technologies struggle to distinguish between different supplementary uplink (SUL) cells in a 5G NR network using a single reference signal strength threshold, leading to inefficiencies in random access processes.
Innovation Solution
Configuring different SUL configuration information in different downlink beams, utilizing SUL identifiers, validity identifiers, priority information, and SSB indexes to enable UE to select the appropriate SUL based on specific scenarios, and employing supplementary downlink signals (SDLs) to filter out non-functional SULs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single RSRP threshold is used to distinguish SUL cells, then the configuration is simple, but different SULs cannot be distinguished from each other
Solution Approach 1:
The patent applies local quality by associating different RSRP thresholds with different downlink beams. Each beam serves a specific spatial direction and has its own threshold configuration, allowing the system to distinguish between SUL cells in different spatial locations. This resolves the contradiction by making the threshold configuration locally optimized for each beam direction rather than using a single global threshold.
Solution Approach 2:
The patent introduces a spatial dimension through beam-based configuration. Instead of using a single scalar threshold, the system now uses multiple thresholds indexed by beam identifiers (SSB indexes). This adds a spatial dimension to the threshold selection process, enabling differentiation of SUL cells based on their spatial relationship to the gNB, thereby resolving the inability to distinguish different SULs.
2Device complexity
If multiple SULs are configured without beam association, then the configuration is simple, but SUL selection accuracy deteriorates
Solution Approach 1:
The patent associates specific SUL configurations with specific downlink beams, creating localized configuration regions. Each beam direction has its own SUL configuration and threshold, allowing the UE to select the appropriate SUL based on the beam it receives. This improves SUL selection accuracy by matching the SUL choice to the spatial direction of the downlink signal.
Solution Approach 2:
The system uses the downlink beam measurement results as feedback to guide SUL selection. The UE measures the RSRP of different downlink beams and uses these measurements to determine which SUL configuration to apply. This feedback mechanism ensures that SUL selection is based on actual channel conditions rather than blind selection, improving reliability.
3Measurement precision
If beam-specific SUL configuration is implemented, then SUL distinction capability is improved, but device complexity increases
Solution Approach 1:
The patent uses the existing downlink beam infrastructure for dual purposes: both for downlink communication and for SUL cell distinction. The same beam structure that provides spatial diversity for downlink also serves as the basis for SUL configuration and selection. This multi-functionality reduces the need for separate SUL-specific infrastructure, thereby limiting the increase in complexity.
Solution Approach 2:
The gNB pre-configures SUL parameters and thresholds for each downlink beam before the UE needs to select an SUL. This preliminary configuration allows the UE to simply follow the pre-established rules when making SUL selection, rather than performing complex real-time calculations. The complexity is shifted to the network side during configuration, simplifying the UE operation.
4Device complexity
If a single threshold is used for all SULs, then the configuration is simple, but random access efficiency deteriorates
Solution Approach 1:
The patent applies local quality by configuring different RSRP thresholds for different downlink beams. Each beam direction has its own optimized threshold that reflects the specific propagation conditions in that direction. This allows UEs in different spatial locations to make more accurate SUL selection decisions, improving random access success rates and overall efficiency.
Solution Approach 2:
The patent changes the threshold parameter from a single scalar value to a set of values indexed by beam identifier. This parameter transformation enables the system to adapt threshold settings to different spatial conditions, improving the accuracy of SUL selection and thereby enhancing random access efficiency without requiring complex real-time adjustments.
Data Source
AI summary
The method includes: receiving, by user equipment UE, supplementary uplink SUL configuration information, wherein the SUL configuration information comprises a plurality of SULs, a plurality of supplementary downlink SDLs respectively matching the plurality of SULs, and SDL measurement configuration information; measuring, by the UE, reference signal strength of the plurality of SDLs based on the SDL measurement configuration information; selecting, by the UE, at least one first SDL from the plurality of SDLs based on the reference signal strength of the plurality of SDLs, and selecting a second SDL from the at least one first SDL, wherein the second SDL has highest reference signal strength in the at least one first SDL; and initiating, by the UE, random access over an SUL corresponding to the second SDL.