HARQ Timing for Shortened TTI Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently performing Hybrid Automatic Repeat and reQuest (HARQ) for shortened Transmission Time Intervals (TTI), which affects latency and service efficiency, particularly in next-generation wireless communication systems requiring reduced latency and flexible frequency band use.
Innovation Solution
A method and apparatus for user equipment in a wireless communication system that receives downlink data signals through a first TTI length and transmits uplink control signals through a second TTI length, where the uplink resource is determined based on the corresponding downlink resource, allowing for efficient HARQ operations even with shortened TTIs by adjusting the timing and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If shortened TTI is used to reduce latency, then service efficiency and latency are improved, but HARQ operation complexity and resource allocation difficulty increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting TTI length between shortened and normal durations based on service requirements. The system changes the time parameter of TTI to optimize between low latency (shortened TTI) and simplified HARQ operations (normal TTI), allowing flexible adaptation to different service types without fixed constraints
Solution Approach 2:
The invention implements dynamics by enabling the TTI length to be dynamically configured and switched between different modes. The base station and user equipment can adaptively change TTI duration according to real-time service conditions, making the system flexible rather than static, thereby resolving the contradiction between shortened TTI benefits and operational complexity
2Loss of time
If shortened TTI is used for downlink data transmission, then latency is reduced, but uplink control signal timing alignment becomes more difficult
Solution Approach 1:
The patent applies parameter changes by independently configuring the length of downlink TTI and uplink TTI. The downlink can use shortened TTI for low latency while the uplink uses normal TTI for easier timing alignment, allowing parameter optimization for each direction separately to resolve the contradiction between latency reduction and timing alignment ease
Solution Approach 2:
The invention segments the downlink and uplink transmission into independent TTI configurations. By dividing the bidirectional communication into separate configurable time intervals, the system can optimize downlink for speed while keeping uplink manageable, addressing the timing alignment difficulty caused by shortened downlink TTI
Data Source
AI summary
Disclosed in the present application is a method for transmitting and receiving signals to and from a base station by a terminal in a wireless communication system. Specifically, the method comprises the steps of: receiving, from the base station, a downlink data signal through a downlink resource of a first transmission time interval (TTI) length; and transmitting, to the base station, an uplink control signal, as a response to the downlink data signal, through an uplink resource of a second TTI length different from the first TTI length, wherein the uplink resource of the second TTI length is determined on the basis of the uplink resource of the first TTI length corresponding to the downlink resource of the first TTI length.