RRC Connection Re-establishment in Mobile Communication Systems
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Solution Overview
Problem
In the Evolved Universal Terrestrial Radio Access (E-UTRA) system, the Radio Resource Control (RRC) protocol connection re-establishment procedure is hindered when the RRC security mode is not activated, leading to operational errors due to the precondition that security mode must be activated before initiating re-establishment, which is not met in cases of maximum re-transmissions in the Radio Link Control (RLC) protocol.
Innovation Solution
A wireless module and event handler in the user equipment (UE) determine whether the UE is in security mode upon failed transmission attempts, performing enter-idle-state actions if not, and initiating RRC protocol connection re-establishment by resetting lower layers, selecting a suitable cell, and transmitting request messages to re-activate security mode if in security mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE initiates RRC protocol connection re-establishment procedure when RLC indicates maximum re-transmissions reached, then connection recovery is attempted, but the procedure fails because security mode has not been activated yet
Solution Approach 1:
The patent applies preliminary action by checking the security mode activation status before initiating the RRC connection re-establishment procedure. The UE determines whether security mode is activated in advance (before the re-establishment procedure starts) and only initiates the procedure when the precondition is satisfied, preventing operational errors while ensuring connection recovery can proceed when conditions are appropriate
2Reliability
If the UE waits for security mode activation before initiating connection re-establishment, then the precondition is satisfied, but connection recovery is delayed when security mode is not activated
Solution Approach 1:
The patent applies dynamics by making the connection re-establishment procedure conditional on the security mode activation status. The system dynamically adjusts behavior based on the current state: if security mode is activated, the procedure proceeds; if not, the UE enters idle state. This dynamic adaptation resolves the contradiction by allowing the system to respond appropriately to different security states rather than rigidly waiting or proceeding regardless
3Ease of operation
If the UE enters idle state when security mode is not activated, then operational errors are prevented, but connection recovery is not attempted
Solution Approach 1:
The patent applies feedback by continuously monitoring the security mode activation status and using this information to determine the appropriate action. The UE receives feedback about the security state and adjusts its behavior accordingly: initiating re-establishment when security is activated, or entering idle state when it is not. This feedback mechanism ensures both operational error prevention and appropriate connection recovery attempts
Data Source
AI summary
An apparatus and method for a radio resource control (RRC) protocol to re-establish connection in a mobile communication system environment are disclosed. A user equipment (UE), for performing connection re-establishment in a connected state with connection to a mobile communication system is provided. When a network problem occurs, the UE shall proceed with the RRC protocol connection re-establishment procedure if the security has been activated. However, if the security has not been activated and the Radio Link Control (RLC) protocol indicates the maximum number of re-transmission has been reached, the UE shall reset lower layers of the RRC protocol, release unnecessary radio resources, and indicate the release of the RRC protocol connection to upper layers of the RRC protocol. Then the UE enters the idle state and waits for the next trigger event.