Random Access Beam Selection Using CSI-RS Thresholds
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Solution Overview
Problem
User equipment often fails to select a suitable beam for random access due to the inability to obtain measurement results of the Synchronization Signal Block (SSB) for the downlink Band Width Part (BWP), which is necessary for determining beam quality in existing communication technologies.
Innovation Solution
A method that determines the measurement results of Channel State Information Reference Signals (CSI-RS) of multiple beams, identifies a target beam with a measurement result greater than a preset threshold, and then determines the corresponding synchronization signal block (SSB) to initiate random access, allowing for beam selection independent of SSB measurement, thereby ensuring a suitable beam is chosen for random access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If user equipment uses SSB measurement results to determine beam quality for random access, then beam selection accuracy is improved, but the system fails when SSB measurement results are unavailable
Solution Approach 1:
The patent introduces CSI-RS measurement results as an intermediary substitute when SSB measurement results are unavailable. The terminal device uses CSI-RS measurements of downlink channels as a mediator to determine beam quality, enabling random access to proceed through alternative measurement data that provides comparable beam selection capability.
Solution Approach 2:
The patent changes the measurement parameter from SSB-specific measurements to CSI-RS measurements of downlink channels. By switching to a different measurement parameter (CSI-RS instead of SSB), the system maintains beam selection functionality even when the original measurement type is unavailable, thus resolving the contradiction between measurement precision and system reliability.
2Measurement precision
If user equipment requires SSB measurement results for beam selection, then measurement accuracy is improved, but device complexity increases due to additional measurement requirements
Solution Approach 1:
The patent makes the measurement system universal by enabling beam quality determination through multiple measurement types. The terminal device can use either SSB measurements or CSI-RS measurements depending on availability, making the measurement system multi-functional and adaptable to different scenarios without requiring dedicated hardware for each measurement type.
Solution Approach 2:
The patent changes the measurement parameter from requiring SSB-specific measurements to accepting CSI-RS measurements of downlink channels. This parameter substitution reduces measurement system complexity by utilizing existing downlink channel measurement capabilities rather than requiring separate SSB measurement infrastructure.
3Reliability
If user equipment performs beam selection based on SSB measurements, then random access success rate is improved, but loss of time occurs when SSB measurements are unavailable
Solution Approach 1:
The patent applies preliminary action by having the terminal device prepare CSI-RS measurement capabilities in advance. Since downlink channel measurements using CSI-RS are already performed for other purposes, the measurement data is readily available when needed for random access beam selection, eliminating the time loss that would occur if measurements had to be performed from scratch.
Solution Approach 2:
The patent uses CSI-RS measurements as an intermediary that is already available in the system. By leveraging pre-existing downlink channel measurement results, the system avoids the time penalty of performing new measurements, thus maintaining random access success rate without incurring additional time loss.
Data Source
AI summary
A random access method includes: when initiating random access, determining a measurement result of channel state information measurement reference signals (CSI-RS) of a plurality of beams; determining a target beam corresponding to a target CSI-RS having a measurement result greater than a preset threshold value; determining a target Synchronization Signal Block (SSB) corresponding to the target CSI-RS; determining a random access preamble and random access timing associated with the target SSB; and initiating random access on the target beam based on the random access preamble and the random access timing. A beam can be determined according to the measurement result of an CSI-RS, without determining the beam according to the measurement result of an SSB, thereby preventing the problem of user equipment (UE) being unable to select a suitable beam for random access due to a measurement result of an SSB not being obtained for a downlink BWP by UE.