Carrier Aggregation HARQ-ACK Timing Management
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Solution Overview
Problem
Current wireless communication systems, such as LTE, face challenges in efficiently utilizing carrier aggregation, particularly in managing HARQ-ACK timing and scheduling across different duplex modes and frequency bands, which affects data transmission and reception efficiency, especially in unlicensed bands where resource availability is aperiodic and discontinuous.
Innovation Solution
The method involves configuring a primary component carrier in a licensed band and a secondary component carrier in an unlicensed band, with HARQ-ACK timing adjusted based on uplink-downlink configuration information, allowing for efficient data transmission and response handling in both time division duplex (TDD) and frequency division duplex (FDD) modes, even when the secondary carrier operates under cross-carrier scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented across different duplex modes and frequency bands, then system capacity and resource utilization are improved, but HARQ-ACK timing management becomes more complex and difficult to coordinate
Solution Approach 1:
The patent segments the carrier aggregation management by introducing separate component carrier indicators (CCIs) for different duplex modes. Downlink carriers are divided into FDD carriers (with CCI values 0-3) and TDD carriers (with CCI values 4-7), allowing independent HARQ-ACK timing management for each segment while maintaining overall system coordination through the unified CCI framework.
Solution Approach 2:
The patent extends the CCI parameter space by adding a duplex mode dimension to the existing carrier indexing. Instead of using a single-dimensional carrier index, the system now uses a two-dimensional indexing scheme where the first dimension identifies the carrier within its duplex mode group, and the second dimension (CCI value range) identifies the duplex mode itself, enabling comprehensive carrier identification across heterogeneous networks.
2Adaptability or versatility
If unlicensed bands are utilized for carrier aggregation, then spectrum resource utilization is improved, but scheduling efficiency and resource availability management deteriorate due to aperiodic and discontinuous resource characteristics
Solution Approach 1:
The patent applies dynamic scheduling mechanisms to unlicensed band carriers, where the eNodeB can flexibly activate or deactivate secondary carriers based on real-time resource availability. The system dynamically adjusts HARQ-ACK timing configurations for unlicensed band carriers, allowing the network to adapt to aperiodic resource characteristics while maintaining efficient scheduling through rapid reconfiguration capabilities.
3Ease of operation
If cross-carrier scheduling is implemented for secondary carriers, then control resource management is improved, but the coordination overhead and scheduling complexity increase
Solution Approach 1:
The patent introduces the primary component carrier as an intermediary that mediates control resource management between the eNodeB and secondary carriers. The primary carrier carries control information including CCI values that identify secondary carriers, acting as a mediator that simplifies the scheduling coordination by providing a centralized control point while reducing direct coordination requirements between multiple secondary carriers.
Data Source
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AI summary
Abstract: The present invention relates to a method for transmitting and receiving a signal by a terminal in a wireless communication system supporting carrier aggregation. A method for transmitting and receiving a signal by a terminal can comprise the steps of: receiving configuration information about component carrier aggregation; on the basis of the configuration information, configuring a primary component carrier in a licensed band and configuring a secondary component carrier in an unlicensed band; transmitting data in a first subframe of the secondary component carrier; and receiving in a second subframe a response to the data. If the primary component carrier in the licensed band is configured as a component carrier on a TDD mode, the second subframe can be configured on the basis of a HARQ-ACK timing in a first condition.