Parallel Access Procedures for Fast RRC Reestablishment
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Solution Overview
Problem
In wireless communication systems, particularly in 3GPP LTE and NR, the process of re-establishing a radio resource control (RRC) connection after a failure can be time-consuming, leading to service interruptions due to the need to transition from an active state to an idle state and back, especially when access procedures at selected cells fail.
Innovation Solution
A method and device that select multiple resources within a cell based on the type of failure, trigger multiple access procedures mapped to these resources, and perform multiple access transmissions to quickly re-establish the RRC connection, potentially using duplicate reestablishment requests across different resources or cells to expedite the recovery process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single access procedure is used for connection reestablishment, then the procedure is simple, but the service interruption time increases
Solution Approach 1:
The patent segments the access procedure into multiple parallel attempts using different resources (preambles, carriers, bandwidth parts) within the same cell. Instead of a single sequential access procedure, the UE divides the reestablishment process into multiple independent access attempts, each using a different resource, thereby reducing the time to successfully reestablish connection while maintaining manageable complexity through organized resource selection.
Solution Approach 2:
The patent introduces additional dimensions to the access procedure by utilizing multiple resources across different domains: multiple random access preambles in the time domain, multiple uplink carriers in the frequency domain, and multiple bandwidth parts. This multi-dimensional resource utilization transforms a single-dimension sequential process into a parallel multi-dimensional process, reducing service interruption time without proportionally increasing complexity.
2Speed
If multiple access procedures are triggered in parallel, then the connection reestablishment speed increases, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple access resources (preambles, carriers, bandwidth parts) before connection failure occurs. The network provides the UE with a pool of available resources in advance through RRC configuration, so that when connection reestablishment is needed, the UE can immediately select and use pre-prepared resources without complex real-time decision-making, thus achieving fast parallel access procedures with controlled complexity.
Solution Approach 2:
The patent uses copying by duplicating access requests across multiple resources. The UE creates copies of the RRC reestablishment request message and transmits them simultaneously through different preambles, carriers, or bandwidth parts. This copying approach simplifies the complexity by using identical request content across multiple channels rather than requiring complex differentiation logic, while achieving fast parallel reestablishment.
3Reliability
If multiple resources are used for access procedures, then the connection reliability improves, but the resource consumption increases
Solution Approach 1:
The patent applies local quality by selectively using different resource qualities based on the specific failure scenario and network configuration. The UE evaluates available resources and selects appropriate ones for each access attempt, using higher-quality resources (e.g., dedicated preambles, licensed carriers) when available and falling back to alternative resources only when necessary. This localized resource quality selection improves reliability while avoiding unnecessary resource consumption across all possible resources.
Solution Approach 2:
The patent implements discarding and recovering by attempting access on multiple resources but discarding unsuccessful attempts and recovering through alternative resources. The UE systematically tries different preambles, carriers, or bandwidth parts, discarding resources that fail to respond or return errors, and recovering connection through remaining available resources. This approach ensures high reliability through multiple attempts while managing resource consumption by not persisting with failed resource allocations.
Data Source
AI summary
A method and apparatus for multiple accesses for fast connection reestablishment in a wireless communication system is provided. Upon detecting a failure, a wireless device selects multiple resources of one cell based on a type of the failure. Then, the wireless device triggers multiple access procedures each of which is mapped to each of the multiple resources of the one cell respectively, and performs multiple access transmissions for the multiple access procedures via the multiple resources of the one cell.