TDD Uplink Timing Advance Offset Configuration
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Solution Overview
Problem
Existing LTE Time Division Duplex (TDD) systems lack a detailed solution for indicating uplink transmission timing advance, which is crucial for synchronizing uplink data transmission due to the involvement of uplink-to-downlink guard periods, differing from Frequency Division Duplex (FDD) systems.
Innovation Solution
A method and apparatus for implementing uplink transmission timing advance in TDD systems by configuring a TA adjustment offset in User Equipment (UE), where the UE receives a TA command, searches a pre-configured TA adjustment indicating table, adds a TA offset, and transmits uplink data according to the adjusted timing advance, aligning with FDD system principles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single Guard Period (GP) is used in TDD systems to include both downlink-to-uplink and uplink-to-downlink guard periods, then the system structure is simplified, but the timing advance indication becomes inaccurate because the uplink-to-downlink guard period cannot be properly implemented
Solution Approach 1:
The patent segments the single Guard Period into two separate guard periods: downlink-to-uplink guard period (T_DU) and uplink-to-downlink guard period (T_UD). This segmentation allows each guard period to be independently configured and managed, enabling accurate timing advance indication while maintaining clear system structure.
Solution Approach 2:
The patent introduces a timing advance offset parameter that is pre-configured in the UE based on the uplink-to-downlink guard period. This preliminary configuration ensures that the UE can accurately determine the timing advance before actual uplink transmission begins, resolving the accuracy issue.
2Ease of operation
If TDD systems follow the same timing advance indication method as FDD systems, then implementation is simplified, but the specific requirements of TDD systems involving uplink-to-downlink switching are not met
Solution Approach 1:
The patent applies local quality by making the timing advance indication method adaptive to the specific duplexing mode. For TDD systems, the method incorporates the uplink-to-downlink guard period offset, while FDD systems continue to use the traditional method. This localized adaptation ensures both simplicity and TDD-specific requirement fulfillment.
Solution Approach 2:
The patent changes the timing advance parameter by introducing an offset component specifically for TDD systems. The timing advance becomes TA' = TA + T_UD, where TA is the original timing advance and T_UD is the uplink-to-downlink guard period offset. This parameter modification enables TDD-specific functionality while maintaining compatibility with existing FDD operations.
3Measurement precision
If the uplink reception timing window is advanced to accommodate TDD switching, then uplink data can be received accurately, but the time interval between downlink and uplink transmissions is reduced
Solution Approach 1:
The patent performs the timing advance adjustment in advance by pre-configuring the offset parameter in the UE. This preliminary action allows the UE to proactively adjust its transmission timing without requiring real-time window advancement, thus preserving the time interval between downlink and uplink transmissions while ensuring accurate reception.
Data Source
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AI summary
In one embodiment, a UE receives a TA command, searches a TA adjustment indicating table for a TA value corresponding to the TA command; wherein the TA adjustment indicating table is pre-configured in the UE, and the TA adjustment indicating table comprises a relationship between the TA command and the TA value; each item in the TA adjusting indicating table is configured the same as a timing advance adjusting indicating table in a Frequency Division Duplex FDD system. The UE adds the TA value corresponding to the TA command and a pre-configured TA adjusting offset to obtain a practical uplink transmission timing advance TA', and transmits uplink data according to the TA'.