TDD Frame Structure Combining Downlink and Uplink HARQ-ACK
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Solution Overview
Problem
The current TDD LTE system experiences long data transmission delays due to the non-timely feedback of uplink control information, particularly HARQ-ACK, leading to inefficiencies in data transmission and high implementation and standardization complexities.
Innovation Solution
Introduce a first subframe structure in the TDD frame structure that includes symbols for downlink and uplink transmissions, allowing for the integration of uplink control information feedback in downlink subframes, thereby reducing HARQ round-trip time and enabling flexible configuration of uplink and downlink symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If HARQ-ACK feedback is transmitted only in uplink subframes using existing TDD configurations, then the system maintains simple frame structure, but the HARQ round-trip time becomes long and data transmission delay increases
Solution Approach 1:
The patent combines downlink and uplink transmissions within the same subframe by introducing a new subframe structure that contains both downlink symbols and uplink symbols. This merging allows HARQ-ACK feedback to be transmitted in the same subframe where downlink data is received, significantly reducing the HARQ round-trip time while maintaining manageable frame structure complexity through standardized design.
Solution Approach 2:
The patent introduces dynamic flexibility in subframe configuration by allowing the last symbol of a downlink subframe to be used for uplink control information transmission. This dynamic adjustment enables the system to adapt the uplink-downlink configuration based on traffic requirements, reducing transmission delays without requiring complete reconfiguration of the frame structure.
2Adaptability or versatility
If multiple uplink-downlink configurations are supported in TDD system, then the system provides good adaptability to different traffic patterns, but the HARQ timing becomes complex and implementation difficulty increases
Solution Approach 1:
The patent creates a universal subframe structure that can function in multiple configurations. By designing the new subframe type to accommodate both downlink and uplink transmissions with standardized fields, the system can support various traffic patterns while maintaining consistent HARQ timing rules, thereby reducing implementation complexity across different configurations.
Solution Approach 2:
The patent simplifies HARQ timing by changing the parameter of feedback timing from configuration-specific variable delays to fixed timing relationships. The new subframe structure establishes universal timing rules where HARQ-ACK is transmitted in the same subframe or with fixed offset, eliminating the need for complex configuration-specific timing calculations while preserving adaptability through flexible resource allocation.
3Productivity
If HARQ-ACK feedback delay is reduced by enabling feedback in downlink subframes, then data transmission efficiency improves, but the frame structure becomes more complex
Solution Approach 1:
The patent merges downlink data transmission and uplink control feedback into the same subframe through a unified structure. This combination enables immediate HARQ-ACK feedback for downlink transmissions, dramatically improving data transmission efficiency while controlling frame structure complexity through standardized field definitions and consistent formatting that can be processed by existing system components.
Data Source
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AI summary
This disclosure relates to the field of wireless communications technologies, and in particular, to an information transmission apparatus, method, and system, so as to resolve a problem that a data transmission delay is relatively long because uplink control information is not fed back in a timely manner. In a communications apparatus provided in an embodiment, a processing module is configured to determine a frame structure of a serving cell, where in this frame structure, one radio frame includes at least one first subframe, the first subframe includes: a first part: a symbol used for downlink transmission; a second part: a guard period GP; and a third part: a symbol used for uplink transmission, and the uplink transmission includes uplink control information transmission; and a transceiver module is configured to send and receive information in the serving cell according to the frame structure, determined by the processing module, of the serving cell. The third part is used for uplink control information transmission, so that uplink control information can also be fed back in a subframe used for downlink transmission. Therefore, the problem that a data transmission delay is relatively long because uplink control information is not fed back in a timely manner is resolved.