UE Frame Timing Difference Measurement in Asynchronous EN-DC
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Solution Overview
Problem
In the context of 5G mobile communication, user equipment (UE) faces challenges in measuring and reporting the System Frame Number (SFN) and Frame Timing Difference (SFTD) between E-UTRA and NR cells, particularly in asynchronous EN-DC operation, where the downlink timing references of E-UTRA and NR cells are not synchronized, leading to failures in detecting the Synchronization Signal Block (SSB) of the NR cell and configuring it as a Primary SCell.
Innovation Solution
The proposed method involves a UE measuring the frame timing difference between E-UTRA and NR cells using a System Frame Number (SFN) offset and frame boundary offset, with or without a measurement gap, to accurately detect the SSB of the NR cell and report the SFTD to the E-UTRA cell, thereby enabling proper configuration of the NR cell as a Primary SCell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If asynchronous EN-DC operation is performed without knowing downlink timing reference difference, then the UE can operate with both E-UTRA and NR cells simultaneously, but the UE fails to detect the SSB of the NR cell and cannot measure SFTD
Solution Approach 1:
The patent applies preliminary action by having the network pre-configure SMTC (Synchronization Signal Measurement Time Configuration) information including timing reference difference before the UE performs SSB detection. This allows the UE to advance prepare the correct measurement timing window based on pre-acquired timing reference information, ensuring successful SSB detection in asynchronous EN-DC operation.
2Device complexity
If the UE uses SMTC information based on E-UTRA downlink timing reference, then the measurement configuration is simple, but the UE cannot detect SSB of NR cell due to timing misalignment
Solution Approach 1:
The patent introduces timing reference difference information as an intermediary parameter that mediates between E-UTRA and NR timing references. The network provides this intermediate timing offset information to the UE, allowing the UE to translate E-UTRA-based SMTC configuration into correctly aligned NR SSB measurement timing, thus resolving the timing misalignment without increasing configuration complexity.
3Productivity
If the UE performs SSB detection without measurement gap, then the operation is efficient, but the UE cannot accurately measure frame timing difference in asynchronous operation
Solution Approach 1:
The patent applies preliminary action by pre-providing timing reference difference information to the UE before SSB detection. This allows the UE to perform measurements efficiently without measurement gap while still achieving accurate frame timing difference measurement, as the preliminary timing information enables correct measurement window positioning.
Data Source
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AI summary
There is provided a method for measuring a frame timing difference. The method performed by a User Equipment (UE) and comprises: based on (i) that an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (E-UTRA) cell is configured for a primary cell and based on (ii) that a secondary cell is not configured, measuring the frame timing difference between the E-UTRA cell and a New Radio (NR) cell based on a Synchronization Signal (SS)/Physical Broadcast Channel (PBCH) Block (SSB) Measurement Time Configuration (SMTC) period, wherein the NR cell is found regardless of a position of a SSB of the NR cell; and reporting a System Frame Number (SFN) and Frame Timing Difference (SFTD) based on the frame timing difference to the E-UTRA cell.