Uplink Timing Reference Carrier Selection in Multi-Carrier LTE Terminals
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Solution Overview
Problem
In the context of LTE mobile communication systems, existing technologies face challenges in improving uplink data rate and end-user Quality of Service (QoS) due to requirements such as per-carrier uplink transmission timing management and multi-carrier random access, particularly when using multiple uplink carriers.
Innovation Solution
The method involves configuring secondary carriers into a Secondary-Timing Advance Group (S-TAG), deactivating the downlink timing reference carrier, and determining if other activated secondary carriers can serve as a new downlink timing reference carrier to manage uplink transmission timing effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple uplink carriers are used to improve data rate, then uplink data rate is improved, but per-carrier uplink transmission timing management complexity increases
Solution Approach 1:
The patent groups multiple secondary carriers into a Secondary-Timing Advance Group (S-TAG) and applies a single timing advance value to all carriers within the group. This merging approach consolidates the timing management of multiple carriers into a unified structure, reducing the complexity of per-carrier timing management while maintaining the high data rate benefits of multiple carriers.
Solution Approach 2:
The patent designates one downlink carrier as a timing reference carrier that serves the entire S-TAG. This single reference carrier provides timing information universally applied to all uplink carriers in the group, eliminating the need for separate timing management mechanisms for each carrier and simplifying the overall system complexity.
2Productivity
If multiple uplink carriers are used to improve data rate, then uplink data rate is improved, but multi-carrier random access requirements increase
Solution Approach 1:
The patent applies the same timing advance value derived from random access procedures on one carrier to all other carriers in the S-TAG. This merging of timing synchronization across carriers reduces the random access requirements from being carrier-specific to being group-wide, thereby reducing complexity while maintaining multi-carrier functionality.
3Adaptability or versatility
If downlink timing reference carrier is deactivated, then carrier flexibility is improved, but timing reference availability may be compromised
Solution Approach 1:
The patent introduces the concept of a timing reference carrier that acts as an intermediary within the S-TAG. Even when the primary downlink timing reference carrier is deactivated, another carrier within the same TAG can serve as the timing reference, ensuring continuous timing reference availability while maintaining carrier flexibility for deactivation/activation operations.
Data Source
AI summary
The present invention relates to a method and apparatus for transmitting data using a multi-carrier in a mobile communication system. The method of transmitting data in user equipment of a wireless communication system using a carrier aggregation technique according to an embodiment of the present invention includes setting secondary cells included in an S-TAG (Secondary-Timing Advance Group) configured of only secondary cells (SCells), deactivating a downlink timing reference cell in the S-TAG; determining whether other activated secondary cells exist besides the deactivated downlink timing reference cell in the S-TAG, and when the other activated secondary cells exist in the S-TAG, setting one of the other activated secondary cells as a new downlink timing reference cell. According to the present invention, uplink transmission speed can be increased in the user equipment and user QoS can be improved by transmitting data using one or more uplink carriers in the terminal.