Self-Contained TDD Subframe for 5G Low Latency
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Solution Overview
Problem
The legacy frame structure of 3GPP LTE is unable to meet the reduced latency requirements of 5G wireless communication systems, particularly for applications like real-time control and tactile internet, which demand data transmission latency of 1 ms, whereas the existing structure only achieves 10 ms latency.
Innovation Solution
A new frame structure is proposed that includes a self-contained subframe structure with a DL control zone, a guard period, and a UL control zone, allowing for simultaneous DL and UL data transmission within a single subframe, enabling flexible configuration of DL/UL traffic and reducing latency to less than 1 ms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a legacy frame structure with 1 ms TTI is used, then the system maintains compatibility with existing LTE infrastructure, but it cannot satisfy the 1 ms data requirement latency for 5G applications
Solution Approach 1:
The frame structure is segmented into self-contained subframes where each subframe contains both DL and UL resources along with guard periods. This segmentation enables independent processing and transmission within each subframe, reducing overall latency while maintaining structural organization compatible with existing LTE frameworks.
Solution Approach 2:
The frame structure employs dynamic configuration where the positions and lengths of guard periods can be adjusted based on traffic conditions. This dynamic adaptation allows the system to optimize latency performance for time-sensitive applications while maintaining flexibility for various traffic patterns, resolving the contradiction between low latency and structural complexity.
2Reliability
If guard periods are inserted between DL and UL transmissions to prevent interference, then interference is reduced, but transmission efficiency decreases due to wasted time resources
Solution Approach 1:
Guard periods are applied locally only where needed between DL and UL transmissions rather than uniformly across the entire frame structure. This localized application prevents interference in critical transition zones while minimizing the impact on overall transmission efficiency, allowing high-speed data transmission in other regions.
Solution Approach 2:
The system uses partial guard periods that are just sufficient to prevent interference rather than excessive guard periods. By applying the minimum necessary guard time locally, the system achieves reliable interference prevention while maximizing transmission efficiency in the remaining time resources.
3Loss of time
If the frame structure is optimized for low latency with shorter subframes, then latency is reduced, but flexibility in configuring DL/UL traffic patterns is limited
Solution Approach 1:
The self-contained subframe structure serves multiple functions simultaneously: it provides low-latency transmission through compact design, enables flexible DL/UL configuration through configurable resource allocations, and maintains compatibility with existing LTE structures. Each subframe can be independently configured for different traffic patterns while maintaining the overall low-latency framework.
Solution Approach 2:
The system allows dynamic changes in frame parameters such as subframe length, guard period position, and resource allocation ratios to adapt to different traffic conditions. This parameter flexibility enables the same low-latency structure to support diverse DL/UL traffic patterns, resolving the contradiction between latency optimization and configuration versatility.
Data Source
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AI summary
This method for a communication device to transmit/receive signals by using a TDD scheme in a wireless communication system may comprise the steps of: receiving information related to a guard period (GP) position in a data zone of a particular subframe; receiving downlink data in the data zone of the particular subframe on the basis of the information related to the GP position; and transmitting uplink data in the data zone of the particular subframe on the basis of the information related to the GP position.