Random Access Preamble Failure Handling in Dual Connectivity
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Solution Overview
Problem
In wireless communication systems, particularly in dual connectivity scenarios, the random access procedure can fail after reaching a maximum number of preamble transmissions, leading to unnecessary radio resource control (RRC) connection re-establishment and interference issues, especially when communicating with secondary eNodeBs (SeNBs).
Innovation Solution
A method is introduced where, upon reaching the maximum number of random access preamble transmissions, the uplink transmission is stopped for the group of cells belonging to the secondary node, and an indication of preamble transmission failure is sent to the master node, preventing unnecessary RRC connection re-establishment and avoiding wrong transmissions to secondary eNodeBs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the random access procedure continues until maximum preamble transmissions are reached, then the terminal attempts to maintain connection with the secondary node, but unnecessary RRC connection re-establishment occurs and interference issues arise
Solution Approach 1:
The invention applies preliminary action by detecting random access failure before the maximum number of preamble transmissions is reached. The terminal monitors the random access procedure and identifies failure conditions (such as receiving a random access response indicating failure or detecting that the maximum number has been reached)并采取 preventive action by stopping uplink transmissions to the secondary node and notifying the master node, thereby avoiding the harmful effects of continued transmission and unnecessary RRC connection re-establishment
Solution Approach 2:
The invention converts the harmful situation of random access failure into a beneficial outcome by using the failure detection mechanism to trigger a controlled stop of uplink transmissions. Instead of allowing continued failed transmissions that cause interference and unnecessary re-establishment, the system leverages the failure condition to initiate a clean termination procedure that protects the master node connection and avoids harmful side effects
2Productivity
If uplink transmission continues to the secondary node after random access failure, then the terminal maintains transmission activity, but wrong transmissions to secondary eNodeBs occur and resources are wasted
Solution Approach 1:
The invention implements feedback by having the terminal monitor the random access procedure outcomes and use this information to control subsequent uplink transmissions. When random access failure is detected, the terminal provides feedback to stop further uplink transmissions to the secondary node and notifies the master node, ensuring that no further wrong transmissions occur and radio resources are not wasted on unsuccessful communication attempts
Data Source
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AI summary
A method and apparatus for performing a random access (RA) procedure in a wireless communication system is provided. A user equipment (UE) establishes (S100) connection with a first node and a second node, and transmits (S110) an RA preamble to the second node. If a number of RA preamble transmissions reaches a maximum number, the UE stops (S120) uplink (UL) transmission of all cells in a group to which the second node belongs, and transmits an indication indicating that transmission of the RA preamble has failed to the first node.