RRC Message Polling Bit Inactive State for RACH Resource Saving
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Solution Overview
Problem
In new radio (NR) communications, the RRC connection reestablishment process in terminal devices leads to a waste of RACH resources due to the need for two random access procedures, as the terminal device initiates random access to send RLC status reports after receiving RRC messages with active polling bits.
Innovation Solution
The RRC message sending method involves setting the polling bit in the RLC PDU to an inactive state, preventing the initiation of the RLC polling mechanism and thus avoiding the need for random access procedures when sending RRC messages during the RRC connection reestablishment process, allowing the terminal device to save RACH resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the polling bit in RLC PDU is set to active state when sending RRC message, then the terminal device can feed back RLC status report to ensure reliable delivery, but the terminal device must initiate random access procedure which wastes RACH resources
Solution Approach 1:
The patent changes the state of the polling bit parameter from active (1) to inactive (0) when sending RRC messages during RRC connection reestablishment. This parameter change disables the RLC polling mechanism, preventing the terminal from initiating random access to send RLC status reports, thereby saving RACH resources while maintaining appropriate reliability for RRC message delivery in the reestablishment context
2Loss of information
If the RLC polling mechanism is started when sending RRC message, then the terminal device can send RLC status report through random access, but the number of random access procedures increases causing inefficiency in RRC connection reestablishment
Solution Approach 1:
The patent extracts the polling bit setting from the default active state and explicitly sets it to inactive state for RRC messages during reestablishment. This extraction separates the RRC message transmission from the RLC status report feedback mechanism, eliminating the need for random access procedures and improving reestablishment efficiency without losing essential RRC signaling
Data Source
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AI summary
This application provides a radio resource control RRC message sending method and an apparatus. According to the method, a distributed unit DU determines not to start an RLC polling mechanism when sending an RRC message to a terminal device, so that when sending the RRC message to UE, the DU sets a polling bit in a header of an RLC PDU carrying the RRC message to be in an inactive state. Therefore, after receiving the RRC message, the terminal device does not feed back an RLC status report to the DU. Therefore, the terminal device does not need to initiate a random access procedure to obtain an uplink transmission resource for sending the RLC status report to the DU, thereby saving random access resources.