TDD Cell HARQ-ACK Timing via Reversed Subframe Patterns
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in signal transmission and reception, particularly in Time Division Duplex (TDD) systems, where existing methods struggle to optimize subframe patterns for efficient data exchange and HARQ-ACK timing, leading to increased delays and reduced scheduling flexibility.
Innovation Solution
The proposed method configures a first TDD cell with a specific subframe pattern and a second TDD cell with a reversed subframe pattern, allowing for symmetrical UL/DL SF patterns and applying FDD HARQ timing to reduce HARQ timing delays and enhance scheduling flexibility by transmitting HARQ-ACK information in specific UL subframes, independent of the subframe patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If existing TDD subframe patterns are used for signal transmission, then the system maintains compatibility with legacy TDD configurations, but HARQ timing delays increase and scheduling flexibility is reduced
Solution Approach 1:
The patent applies inversion by configuring the second TDD cell with a reversed subframe pattern compared to the first cell. Specifically, if the first cell uses pattern DSUUUDSUUU, the second cell uses UUDDSUUDDS, effectively inverting the UL/DL direction assignments. This inversion enables FDD-like simultaneous UL/DL operations in different cells, reducing HARQ timing delays while maintaining TDD operation mode.
2Productivity
If TDD subframe patterns are optimized for efficient data exchange, then data throughput improves, but HARQ-ACK timing becomes complex and difficult to manage
Solution Approach 1:
The patent applies universality by using a fixed offset value k for HARQ-ACK timing across all DL subframes, regardless of the specific subframe pattern configuration. This universal approach simplifies the timing management mechanism while maintaining support for different subframe patterns (original-cfg #0-6 and reversed-cfg #0-6), enabling the system to achieve both efficient data exchange and manageable HARQ-ACK timing.
3Ease of manufacture
If legacy signal timing is reused in multi-carrier TDD systems, then system compatibility and ease of deployment improve, but scheduling flexibility and performance optimization are limited
Solution Approach 1:
The patent applies segmentation by dividing the multi-carrier TDD system into multiple cells, each with independently configurable subframe patterns. The first cell uses original-cfg pattern while the second cell uses reversed-cfg pattern, allowing each segment to be optimized independently. This segmentation enables legacy signal timing to be reused within each cell while providing overall system flexibility through inter-cell pattern differentiation.
Data Source
AI summary
The present invention relates to a wireless communication system. Particularly, the present invention relates to a method for transmitting control information and a device therefor, the method comprising the steps of: configuring a first TDD cell having a first subframe pattern; configuring a second TDD cell having a second subframe pattern, wherein a direction for transmitting according to the first subframe pattern and a direction for transmitting according to the second subframe pattern differ from each other in each subframe; receiving a PDSCH in a DL subframe #n of the first TDD cell; and transmitting HARQ-ACK information for the PDSCH in a UL subframe #n−k of the second TDD cell, wherein n is an integer greater than or equal to zero, and k is a positive integer fixed regardless of the first subframe pattern and the second subframe pattern.