C-RNTI Re-synchronization via Temporary Identifier Handling
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Solution Overview
Problem
In wireless communication systems, ensuring that user equipment (UE) is assigned only one valid temporary UE ID by each cell it communicates with, while allowing for seamless handovers and synchronization updates, is challenging due to the need for efficient management of Cell Radio Network Temporary Identifiers (C-RNTIs).
Innovation Solution
The UE sends a random access preamble to receive a Temporary C-RNTI from a base station, which is used if a valid C-RNTI is not available, and this Temporary C-RNTI is either promoted to a valid C-RNTI upon successful access or discarded in favor of an existing valid C-RNTI, allowing for simplified C-RNTI handling across various scenarios like initial access, handovers, and timing synchronization updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE always transmits its valid C-RNTI during random access procedures, then the base station can maintain accurate C-RNTI synchronization, but the handover process becomes more complex and time-consuming
Solution Approach 1:
The patent applies local quality by differentiating the random access behavior based on the UE's current state. When the UE has a valid C-RNTI, it transmits this identifier during random access. When the UE lacks a valid C-RNTI, it performs traditional random access without C-RNTI transmission. This localized adaptation resolves the contradiction by optimizing each scenario specifically rather than applying a uniform approach.
2Ease of operation
If the UE discards the Temporary C-RNTI and uses the valid C-RNTI, then the C-RNTI management is simplified, but the base station may lose track of the UE if the valid C-RNTI is not transmitted
Solution Approach 1:
The patent implements feedback by having the UE transmit its valid C-RNTI to the base station during random access procedures when available. This feedback mechanism allows the base station to verify and update its C-RNTI record for the UE, ensuring accurate identification and resolution of any C-RNTI synchronization issues while maintaining simplified UE-side C-RNTI management.
3Productivity
If the base station assigns a new C-RNTI during handover, then the UE can maintain continuous communication, but the handover latency increases due to C-RNTI reassignment
Solution Approach 1:
The patent applies preliminary action by having the target base station prepare and assign the valid C-RNTI to the UE before the handover is completed. The source base station forwards this pre-assigned C-RNTI to the UE, so that when the handover occurs, the UE already has the correct identifier for continuous communication with the target base station, eliminating handover latency caused by C-RNTI reassignment.
Data Source
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AI summary
Techniques for re-synchronizing Cell Radio Network Temporary Identifiers (C-RNTIs) in a wireless communication system are described. In one design, a user equipment (UE) sends a random access preamble for random access. A base station receives the random access preamble, assigns a Temporary C-RNTI to the UE, and sends a random access response including the Temporary C-RNTI. The UE uses the Temporary C-RNTI as a C-RNTI for itself if a valid C-RNTI is not already available. The UE discards the Temporary C-RNTI and uses the valid C-RNTI if available. The UE sends a transmission after receiving the random access response, and the transmission may include the valid C-RNTI if available. For handover, the base station (a target base station) receives a handover request from a source base station, assigns the valid C-RNTI to the UE, and sends the valid C-RNTI to the source base station for forwarding to the UE.