Wireless Frame Structure for 5G Low Latency and Asymmetrical Traffic
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Solution Overview
Problem
The legacy 3GPP LTE frame structure with a 1 ms TTI is unable to meet the reduced latency requirements of 5G wireless communication systems, which aim for data latency of 1 ms, necessitating a new frame structure to support lower latency and asymmetrical DL/UL traffic.
Innovation Solution
A new frame structure is proposed with subframes containing a downlink region, an uplink region, and a guard period, where the guard period's length corresponds to an integer multiple of a unit symbol size, and includes downlink and uplink control channels, allowing for flexible allocation of DL/UL data zones within a single subframe to achieve low latency and efficient traffic asymmetry support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a legacy 1 ms TTI frame structure is used, then the system maintains compatibility with existing LTE infrastructure, but it cannot satisfy the reduced latency requirement of 1 ms data transmission for 5G applications
Solution Approach 1:
The subframe is segmented into multiple slots, and each slot is further divided into multiple mini-slots. This hierarchical segmentation allows the system to achieve finer time granularity (enabling 1 ms latency) while maintaining the overall LTE frame structure for compatibility.
Solution Approach 2:
The patent introduces dynamic slot and mini-slot configurations where the number of symbols, resource allocation, and guard period positions can be flexibly adjusted based on traffic conditions. This dynamic structure enables the system to adapt to varying latency requirements while maintaining backward compatibility.
2Adaptability or versatility
If the guard period length is increased to accommodate flexible DL/UL allocation, then asymmetrical traffic handling is improved, but the available data transmission time is reduced
Solution Approach 1:
The guard period is segmented into multiple candidate positions within the slot structure (e.g., before DL data, before UL data, or between them). This allows the system to select the optimal guard period position based on traffic asymmetry requirements without permanently sacrificing data transmission capacity.
Solution Approach 2:
The guard period configuration is made dynamic, where its position and length can be adjusted based on real-time traffic conditions. When DL traffic dominates, the guard period is positioned to optimize DL protection; when UL traffic dominates, it is repositioned accordingly, thus maintaining data transmission efficiency while providing flexibility.
3Reliability
If control channels occupy more symbols in time domain, then control signaling reliability is improved, but the available resources for data transmission are reduced
Solution Approach 1:
The patent introduces a new dimensional organization of control channels by placing them at specific symbol positions within slots and mini-slots rather than dedicating entire subframes. Control channels are distributed across multiple time-frequency resources, achieving reliability through diversity while preserving data resources through efficient spatial and temporal multiplexing.
Data Source
AI summary
This method for a communication device to transmit/receive signals in a wireless communication system comprises the step of transmitting/receiving signals by using multiple subframes having a preset frame structure, wherein each of the multiple subframes comprises a downlink region and an uplink region, and with respect to the same region corresponding to the same frequency band in the preset frame structure, the downlink region and the uplink region may be allocated respectively to a first subframe and a second subframe among the multiple subframes.