Timing Advance Offset for FDD TDD Carrier Aggregation
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Solution Overview
Problem
In LTE wireless communication systems, handling timing advance offsets for TDD and FDD carrier aggregation poses challenges due to differences in duplexing systems, leading to potential timing misalignments and increased operational complexity.
Innovation Solution
A method is introduced where a user equipment (UE) determines a timing advance (TA) offset value for uplink transmissions based on whether the primary component carrier (PCC) is configured as TDD or FDD, simplifying the management of TA offsets and reducing the need for multiple timing adjustment groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate timing advance groups are configured for TDD and FDD component carriers, then timing accuracy is maintained, but device complexity and operational complexity increase
Solution Approach 1:
The patent combines TDD and FDD component carriers into a single timing advance group, using one unified TA value for uplink transmissions across both carrier types. This merging approach eliminates the need for separate timing advance groups, thereby reducing device complexity and operational overhead while maintaining adequate timing synchronization for both TDD and FDD carriers.
Solution Approach 2:
The patent implements a universal timing advance mechanism where a single TA value serves multiple functions across different duplexing modes (both TDD and FDD). This multi-functional approach allows the same timing advance parameter to handle uplink synchronization for heterogeneous carrier types, simplifying the system architecture and reducing the number of configuration parameters needed.
2Reliability
If multiple timing adjustment groups are used for TDD and FDD CA, then timing misalignment is prevented, but the number of configuration parameters and signaling overhead increase
Solution Approach 1:
The patent merges multiple timing adjustment groups into a single unified timing advance group for TDD-FDD carrier aggregation. By consolidating the timing management functionality, the system reduces the number of configuration parameters and signaling overhead while ensuring that both TDD and FDD carriers operate with synchronized timing through the shared TA value.
3Device complexity
If a single timing advance value is used for both TDD and FDD carriers, then device complexity is reduced, but timing misalignment may occur between different carrier types
Solution Approach 1:
The patent employs a universal timing advance value that functions across both TDD and FDD carrier types within the same timing advance group. This single TA value is applied uniformly to all uplink transmissions regardless of the carrier's duplexing mode, achieving configuration simplicity while maintaining timing synchronization through the shared reference timing mechanism.
Data Source
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AI summary
Aspects of the present disclosure relate to techniques for determining timing of uplink transmissions for UEs communicating with carrier aggregation involving both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers (CCs). A timing advance (TA) offset value for a user equipment (UE) to use for uplink transmissions is determined based, at least in part, on which of the CCs carries a physical uplink control channel (PUCCH).