Timing Reference Selection for Uplink Component Carrier Synchronization
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Solution Overview
Problem
In LTE-Advanced systems with carrier aggregation, accurately confirming the timing adjustment of uplink component carriers is challenging due to different propagation environments and the lack of a clear downlink timing reference in multiple component carrier scenarios, unlike in LTE R8 systems where only a pair of carriers is used.
Innovation Solution
The method involves using a downlink component carrier as a timing reference for uplink component carriers, with instruction signaling sent by the eNodeB to the terminal for initial random access channel processes, allowing for accurate timing adjustment by specifying a downlink component carrier as the timing reference for all uplink carriers within a group or based on specific rules or external commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple downlink component carriers are used in carrier aggregation, then system bandwidth is expanded and data transmission rate is increased, but timing reference clarity deteriorates and TA adjustment accuracy deteriorates
Solution Approach 1:
The patent segments the multiple downlink component carriers by designating one specific downlink component carrier as the timing reference carrier. This segmentation allows the system to handle multiple carriers for high data rate while isolating one carrier to provide clear timing reference, thus resolving the contradiction between expanded bandwidth and timing reference clarity.
Solution Approach 2:
The patent introduces an intermediary mechanism by selecting a specific downlink component carrier to serve as the timing reference. This intermediary carrier mediates between the multiple downlink component carriers and the uplink timing adjustment process, providing a unified timing reference that ensures accurate TA adjustment while maintaining the benefits of carrier aggregation.
2Productivity
If multiple downlink component carriers are used, then system capacity is improved, but device complexity increases due to multiple TA references
Solution Approach 1:
The patent applies universality by designating one downlink component carrier to serve multiple functions: it acts as both a data transmission carrier and the timing reference carrier. This multi-functionality reduces device complexity by eliminating the need for the terminal to manage multiple TA references, while still allowing the system to utilize multiple carriers for enhanced capacity.
3Adaptability or versatility
If different TA reference times are used for different uplink component carriers, then propagation environment differences are accommodated, but synchronization deteriorates across carriers
Solution Approach 1:
The patent merges the timing reference function across all uplink component carriers by having them all reference the same downlink component carrier. This merging approach ensures that all uplink carriers maintain synchronized timing relative to a common reference, preserving carrier synchronization while still allowing the system to adapt to different propagation environments through the eNodeB's control of the timing advance commands.
Data Source
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AI summary
A method, an eNodeB, and a system for timing adjustment to a component carrier are provided. The method includes the following steps: receiving an instruction signaling, in which the instruction signaling is used for instructing a downlink component carrier used as a timing reference for an uplink component carrier; and adjusting the uplink component carrier by using the downlink component carrier as timing reference time. Through the embodiments of the present invention, the downlink component carrier used as the timing adjustment reference for the uplink component carrier is specified in the sent instruction signaling. The timing reference time used by the terminal during the TA adjustment of the uplink component carrier may be clarified and the TA adjustment of the uplink component carrier may be accurately confirmed.