TDD Frame Structure HARQ Timing Standardization
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Solution Overview
Problem
The existing LTE TDD system has varying HARQ-ACK timing for different uplink-downlink configurations, increasing complexity and requiring different HARQ timing for each configuration, which complicates implementation and protocol management.
Innovation Solution
The user equipment and base station determine a frame structure with specific subframe configurations, including downlink, uplink, and special subframes, where the same HARQ timing is used for all configurations, reducing complexity by aligning subframe roles across different uplink-downlink ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different HARQ timing is used for different uplink-downlink configurations in TDD system, then the system can support various uplink-to-downlink ratios, but the implementation complexity and protocol complexity increase
Solution Approach 1:
The patent applies universality by making the special subframe serve multiple functions: it acts as both a downlink subframe (for transmitting PDSCH) and an uplink subframe (for transmitting HARQ-ACK), similar to how FDD uplink subframes function. This multi-functionality allows the TDD system to achieve FDD-like simple HARQ timing (fixed 4-subframe delay) while supporting various uplink-to-downlink ratios through flexible configuration of which subframes are designated as special subframes.
Solution Approach 2:
The patent segments the TDD frame structure by introducing special subframes that can be dynamically configured. By dividing the frame into regular downlink subframes, regular uplink subframes, and configurable special subframes, the system can adapt to different uplink-to-downlink ratios while maintaining consistent HARQ timing rules for downlink data transmitted in non-special subframes.
2Adaptability or versatility
If multiple HARQ timing configurations are maintained for different TDD configurations, then various uplink-to-downlink ratios are supported, but the system complexity increases
Solution Approach 1:
The patent makes special subframes universal by allowing them to function similarly to FDD uplink subframes. Any special subframe can receive downlink data and transmit HARQ-ACK with a fixed 4-subframe timing relationship, eliminating the need for configuration-specific timing rules. This universal behavior simplifies the system while maintaining support for different TDD configurations through flexible special subframe placement.
Data Source
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AI summary
Embodiments of the present invention disclose an information sending or receiving method, user equipment, and a base station. The method includes: determining, by user equipment, a frame structure of a serving cell, where a radio frame corresponding to the frame structure includes at least one downlink subframe, at least one uplink subframe, and at least one special subframe, and the special subframe is a first special subframe or a second special subframe; and sending or receiving, by the user equipment, information in the serving cell based on the frame structure, where the special subframe includes a symbol used for downlink transmission, a guard period GP, and a symbol used for uplink transmission, a quantity of symbols used for downlink transmission is greater than a quantity of symbols used for uplink transmission in the first special subframe, and a quantity of symbols used for downlink transmission is less than a quantity of symbols used for uplink transmission in the second special subframe. In the embodiments of the present invention, different uplink-downlink configurations can have same HARQ-ACK timing in a TDD system, so that complexity of the TDD system is reduced.