Layer 2 Radio Link Re-establishment for Fast Connection Recovery
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Solution Overview
Problem
The connection re-establishment process in 3GPP LTE compliant communications systems is inefficient due to the protocol architecture, which treats radio link failure or handover failure as an error case, leading to lengthy recovery procedures and interruptions in user experience.
Innovation Solution
A method for connection management in 3GPP networks that allows for Layer 2 radio link re-establishment, where the network device checks the validity of user equipment (UE) using an authentication identifier derived from the RRC integrity key and identifier, enabling faster recovery by configuring the re-establishment of the connection without requiring full Layer 3 recovery procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full Layer 3 recovery procedures are performed for radio link failure or handover failure, then connection reliability is ensured, but recovery time is excessively long causing user experience interruptions
Solution Approach 1:
The patent segments the connection recovery process into two distinct layers: Layer 2 (MAC/RLC) re-establishment and Layer 3 (RRC) re-establishment. The invention enables fast recovery by attempting Layer 2 re-establishment first, which handles the majority of failure cases quickly. Only if Layer 2 re-establishment fails does the system proceed to the more time-consuming Layer 3 procedure. This segmentation resolves the contradiction by providing a fast path for common cases while maintaining the reliable full recovery path as a fallback.
Solution Approach 2:
The patent implements preliminary action by pre-configuring suspension of downlink data reception at the PDCP layer before initiating re-establishment procedures. Additionally, the network device pre-preares to receive re-establishment requests at both Layer 2 and Layer 3. This preliminary preparation enables faster response time when failures occur, reducing the overall recovery time while maintaining connection reliability.
2Reliability
If the protocol architecture treats radio link failure as an error case requiring full configuration, then connection integrity is maintained, but the recovery process becomes complex and lengthy
Solution Approach 1:
The patent divides the recovery procedure into simplified Layer 2 re-establishment and comprehensive Layer 3 re-establishment. The Layer 2 procedure handles common failures with minimal complexity by re-establishing only MAC and RLC connections without full RRC reconfiguration. This segmentation reduces device complexity for the common case while maintaining connection integrity through the available full Layer 3 procedure as backup.
Solution Approach 2:
The patent employs a lightweight, disposable-like Layer 2 re-establishment mechanism that can be quickly attempted and discarded if failed. This cheap/fast Layer 2 attempt does not require full configuration and can be performed rapidly. Only if this simple attempt fails does the system incur the complexity of full Layer 3 re-establishment, making the overall process less complex for the majority of cases.
3Loss of time
If Layer 2 radio link re-establishment is implemented, then user experience interruptions are reduced, but the risk of incomplete recovery increases
Solution Approach 1:
The patent implements feedback mechanisms where the network device monitors the outcome of Layer 2 re-establishment attempts. If Layer 2 re-establishment succeeds, the system confirms recovery and resumes normal operation. If Layer 2 re-establishment fails or indicates incomplete recovery, the feedback triggers escalation to full Layer 3 re-establishment procedures. This feedback loop ensures recovery completeness while maintaining fast recovery for successful Layer 2 cases.
Solution Approach 2:
The patent provides beforehand cushioning by having the full Layer 3 recovery procedure ready as a safety net before Layer 2 re-establishment is attempted. The system prepares both recovery paths in advance, with the comprehensive Layer 3 procedure standing by to catch any cases where Layer 2 re-establishment proves insufficient. This prior preparation ensures that no recovery case is left incomplete while still enabling fast recovery through Layer 2 when appropriate.
Data Source
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Figure 3
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AI summary
A method for connection management by a user equipment includes transmitting a re-establishment request for a first connection of a first protocol layer in response to determining that a connection re-establishment condition is met, receiving a re-establishment response indicating if a re-establishment of the first connection of the first protocol layer is allowed, and completing the re-establishment of the first connection of the first protocol layer when the re-establishment of the first connection of the first protocol layer is allowed, wherein a context of a second protocol layer of the user equipment is unchanged.