TDD HARQ Subframe Indexing for Signaling Overhead Reduction
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Solution Overview
Problem
In wireless communication systems, performing Hybrid Automatic Retransmit Request (HARQ) operations in subframe units leads to significant signaling overhead due to varying ACK/NACK delays, which complicates data transmission and increases the time required for the HARQ process.
Innovation Solution
A method is introduced where data is transmitted in a first subframe of a frame, and ACK/NACK is received in a second subframe, with the second frame determined based on HARQ processing latency, the number of downlink and uplink subframes used for the HARQ operation, and the first subframe, allowing for efficient subframe indexing to reduce signaling overhead and HARQ operation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If HARQ operation is performed in subframe units with varying ACK/NACK delays, then data transmission flexibility is improved, but signaling overhead increases significantly
Solution Approach 1:
The patent segments the HARQ operation into distinct phases: data transmission phase in downlink subframes and ACK/NACK reception phase in uplink subframes. By dividing the frame into multiple subframes with specific functions, the system achieves flexible data transmission while managing signaling overhead through structured phase separation.
Solution Approach 2:
The patent applies preliminary action by pre-determining the second subframe for ACK/NACK reception based on the first subframe index and HARQ processing latency. This allows the base station and mobile station to anticipate transmission times in advance, reducing the need for complex signaling and minimizing overhead while maintaining transmission flexibility.
2Adaptability or versatility
If HARQ operation is performed in subframe units, then transmission timing flexibility is improved, but time required for HARQ operation increases
Solution Approach 1:
The patent uses preliminary action by calculating and pre-determining the second subframe index based on the first subframe index and HARQ processing latency. This allows both base station and mobile station to anticipate the exact timing for ACK/NACK exchange, eliminating unnecessary waiting time while maintaining the flexibility of subframe-based transmission.
Solution Approach 2:
The patent implements dynamics by allowing the second subframe to be dynamically determined based on the first subframe index and HARQ processing latency. This dynamic timing adjustment enables the system to adapt to different transmission scenarios while minimizing the overall HARQ operation time through optimized subframe selection.
3Reliability
If multiple HARQ channels are allocated to compensate for delay, then transmission reliability is improved, but total delay and system complexity increase
Solution Approach 1:
The patent segments the HARQ process into distinct downlink and uplink phases with specific subframe allocations. By organizing the communication into structured segments rather than using multiple parallel channels, the system achieves reliable transmission through proper phase separation while avoiding the complexity of managing multiple HARQ channels.
Data Source
AI summary
The present invention relates to a method for transmitting and receiving data in a wireless communication system. The method of transmitting data in a wireless communication system according to an embodiment of the present invention supports time division duplex (TDD), and a base station transmits data to a terminal through a first sub-frame of a first frame and receives a confirmatory response to the data through a second sub-frame of a second frame. The second frame is determined according to hybrid automatic retransmit request (HARQ) processing latency which is the minimal required time from the reception of the data to the transmission of the confirmatory response by the first frame and the terminal. The second sub-frame is determined according to both the first sub-frame and the numbers of the downlink and uplink sub-frames of the first frame, wherein the downlink and uplink sub-frames are respectively used in the HARQ operation.