sTTI Special Subframe Configuration for TDD Latency Reduction
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Solution Overview
Problem
Current wireless communication systems, such as 3GPP LTE, face challenges in achieving low latency due to the existing 1 ms transmission time interval (TTI) structure, which is not suitable for next-generation wireless communication systems requiring faster data rates and lower latency.
Innovation Solution
A method for configuring and transmitting special subframes using a short transmission time interval (sTTI) structure in a time division duplex (TDD) system, involving the reception of downlink and transmission of uplink signals during specific pilot time slots with a guard period, allowing for a plurality of sTTI transport blocks and determining the sTTI structure pattern based on special subframe configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a 1 ms transmission time interval (TTI) structure is used, then system stability and compatibility with existing LTE standards are maintained, but latency cannot be reduced below 1 ms
Solution Approach 1:
The patent divides the traditional 1 ms TTI into multiple shorter sTTI segments (e.g., 2-symbol or 3-symbol sTTI). This segmentation allows data transmission to occur in smaller time units, reducing the minimum latency from 1 ms to as low as 0.5 ms or less, while maintaining the overall frame structure for system compatibility
Solution Approach 2:
The patent introduces dynamic TTI length adjustment by allowing the system to flexibly switch between different sTTI configurations (2-symbol, 3-symbol, or longer) based on service requirements. This dynamic adaptation enables low-latency communication for urgent data while maintaining stability for regular traffic, resolving the contradiction between latency reduction and system stability
2Loss of time
If the TTI length is reduced to achieve low latency, then latency requirement is satisfied, but the existing LTE frame structure becomes unsuitable and system complexity increases
Solution Approach 1:
The patent designs the sTTI structure to serve multiple functions: it can be used for both low-latency data transmission and maintain compatibility with existing LTE scheduling mechanisms. The special subframe configuration with DwPTS, GP, and UpPTS regions provides universal applicability across different TDD configurations while supporting sTTI-based transmission
Solution Approach 2:
The patent changes key frame structure parameters by introducing configurable sTTI lengths (2-symbol, 3-symbol, etc.) and special subframe configurations. These parameter changes allow the system to adapt to different latency requirements while maintaining backward compatibility with LTE standards through configurable options rather than fixed structure
3Productivity
If special subframe configuration is implemented with sTTI structure, then latency is reduced and resource control efficiency is improved, but configuration complexity and signaling overhead increase
Solution Approach 1:
The patent performs preliminary configuration by pre-defining special subframe structures with specific DwPTS, GP, and UpPTS allocations. These pre-configured templates reduce the complexity of real-time resource allocation, as the system only needs to select from predefined configurations rather than creating new structures dynamically, thus improving resource control efficiency while limiting configuration complexity
Data Source
AI summary
A method in which a terminal transmits/receives a special subframe in a wireless communication system supporting time division duplex (TDD) according to an embodiment of the present invention includes: a step for receiving information about a special subframe configuration; a step for receiving a downlink signal from a base station during a time corresponding to a downlink pilot time slot (DwPTS) allocated according to the special subframe configuration; and a step for transmitting an uplink signal to the base station during a time corresponding to an uplink pilot time slot (UpPTS) allocated according to the special subframe configuration, wherein the special subframe consists of the DwPTS, a guard period (GP), and the UpPTS, and is received or transmitted through an sTTI structure pattern including a plurality of short transmission time interval (sTTI) transmission blocks, wherein the sTTI structure patterns can be determined according to the special subframe configuration.