Inter-RAT Re-establishment via S-RNTI Parameter Transformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication networks, inter-RAT re-establishment procedures between LTE and NR are complex due to differences in UE identifier formatting, leading to challenges in identifying the UE context and maintaining CN connections during radio link failures or handovers.
Innovation Solution
A method where a wireless device determines a set of parameters associated with the first cell, converts them to match the format of the second RAT, and transmits these parameters in a re-establishment request message to facilitate inter-RAT re-establishment, allowing the second radio network node to identify the first node and re-establish the connection efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inter-RAT re-establishment procedures are implemented between LTE and NR, then connection resilience is improved, but procedure complexity increases due to UE identifier formatting differences
Solution Approach 1:
The patent transforms the UE identifier from LTE format (C-RNTI + physical cell ID) to NR format (full I-RNTI) by encoding additional information including the source gNB ID and cause of failure. This parameter transformation enables compatibility between different RATs while maintaining unique device identification, thereby improving connection resilience without proportionally increasing procedure complexity
Solution Approach 2:
The S-RNTI acts as an intermediary identifier that bridges LTE and NR systems. It contains encoded information about the source cell and failure cause, allowing the target gNB to retrieve relevant context from the source gNB without requiring complex direct interoperability protocols between different RATs
2Measurement precision
If detailed UE context information is transmitted during re-establishment, then connection recovery accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent performs preliminary encoding of UE context information into the S-RNTI identifier before the actual re-establishment procedure. By pre-packaging essential information (source cell ID, failure cause, C-RNTI) into a compact format, the system reduces the amount of signaling needed during the critical re-establishment phase while maintaining accurate context recovery
Solution Approach 2:
The S-RNTI structure implements a nested information hierarchy where multiple layers of UE context are embedded within a single identifier. The outer layer contains source cell identification, the middle layer contains failure cause codes, and the inner layer contains the original C-RNTI. This nested structure enables comprehensive context transmission with minimal signaling overhead
Data Source
AI summary
A wireless device and method for re-establishing a radio connection in a communications network comprising a first RAT and a different second RAT. The wireless device is operating in a first cell served by a first radio network node operating in the first RAT. When a connection failure with the first cell is detected, the wireless device performs a cell selection and selects a second cell served by a second radio network node operating in the second RAT. The second cell is known by the wireless device to be a candidate for re-establishment. The wireless device determines a first set of parameters to be used as an identifier of the wireless device, wherein the first set of parameters is associated with the first cell. The wireless device transmits, to the second cell, a re-establishment request message comprising the first set of parameters.