BWP-Aware Selection Between 2-Step and 4-Step Random Access
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Solution Overview
Problem
Existing wireless communication systems face challenges in selecting the appropriate type and resources for random access procedures due to varying scenarios and priorities, particularly in scenarios involving reconfiguration with sync or lower-layer triggered mobility, leading to inefficiencies in resource utilization.
Innovation Solution
A method for determining the appropriate random access (RA) procedure by assessing configuration with sync, dedicated contention-free RA resources, and measured reference signal received power (RSRP) to select between 2-step and 4-step RA types, ensuring optimal resource utilization based on specific conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the UE selects a random access procedure without considering the specific scenario and configuration, then the procedure can be initiated quickly, but the resource utilization efficiency deteriorates
Solution Approach 1:
The UE dynamically selects the random access procedure type (2-step or 4-step) based on real-time evaluation of multiple conditions including whether reconfiguration with sync was initiated, whether LTM candidate configuration is used, and whether dedicated contention-free RA resources are configured. This dynamic adaptation allows the system to optimize resource utilization while maintaining quick access initiation.
Solution Approach 2:
The invention changes the parameter of random access procedure selection by introducing a multi-condition decision framework that evaluates scenario-specific parameters (reconfiguration with sync initiation, LTM candidate configuration, dedicated contention-free resources) to determine the appropriate RA type, thereby resolving the contradiction between speed and efficiency.
2Loss of time
If the UE always performs 2-step RA when resources are available, then the access time is reduced, but the reliability deteriorates in certain scenarios
Solution Approach 1:
The invention changes the decision parameter for RA type selection from a fixed preference to a conditional evaluation that considers scenario-specific factors. When reconfiguration with sync is initiated for LTM candidate or when dedicated contention-free resources are configured, the UE selects 4-step RA for higher reliability. Otherwise, 2-step RA is preferred for reduced access time, thus resolving the contradiction.
3Productivity
If the UE performs multiple condition checks to select the correct RA procedure, then the resource utilization improves, but the complexity of the selection process increases
Solution Approach 1:
The invention segments the RA procedure selection process into distinct decision branches based on specific conditions. The UE first checks if reconfiguration with sync was initiated, then checks for LTM candidate configuration, and finally checks for dedicated contention-free resources. This segmented approach organizes the complexity into manageable, scenario-specific decision paths.
Solution Approach 2:
The invention performs preliminary condition checks before initiating the RA procedure. By evaluating the reconfiguration with sync initiation status, LTM candidate configuration, and dedicated resource availability in advance, the UE determines the appropriate RA type beforehand, reducing the complexity during actual access while maintaining high resource utilization.
4Reliability
If the UE uses dedicated contention-free RA resources, then the access reliability improves, but the flexibility in procedure selection deteriorates
Solution Approach 1:
The invention changes the selection parameter by introducing scenario-based conditions that override the general preference for 2-step RA. When dedicated contention-free resources are configured or when reconfiguration with sync is initiated for LTM candidate, the UE is directed to use 4-step RA, ensuring reliability in these specific scenarios while maintaining flexibility in other cases.
Data Source
AI summary
A method comprising initiating a random access (RA) procedure, by a reconfiguration with sync, for a bandwidth part (BWP), in circumstances where the reconfiguration with sync was not initiated for recovery using an lower-layer triggered mobility (LTM) candidate configuration, in circumstances where the BWP was configured with the dedicated contention free RA resources for the 4-step RA type, performing 4-step RA, in circumstances where the active BWP was not configured with the dedicated contention free RA resources for the 4-step RA type: in circumstances where the BWP was configured with the dedicated contention free RA resources for the 2-step RA type, performing 2-step RA, in circumstances where the BWP was not configured with the dedicated contention free RA resources for the 2-step RA type, performing 4-step RA; in circumstances where the reconfiguration with sync was initiated for recovery using an LTM candidate configuration: in circumstances where the BWP is configured with RA resources for 2-step RA type: in circumstances where the BWP is not configured with RA resources for 4-step RA type random access, performing 2-step RA, in circumstances where the BWP is configured with RA resources for 4-step RA type: in circumstances where the measured RSRP of the downlink pathloss reference is above the message-A threshold, performing 2-step RA, and in circumstances where the measured RSRP of the downlink pathloss reference is not above the message-A threshold, performing 4-step RA is disclosed.