Flexible TDD Subframe Allocation for Latency Reduction
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Solution Overview
Problem
Current LTE systems have limited flexibility in allocating uplink and downlink subframes, leading to interference issues and fixed resource allocation, which restricts efficient resource utilization and increases latency.
Innovation Solution
The method involves using a special subframe for signaling critical control information and flexibly allocating other subframes for uplink and downlink transmission, allowing for a variable ratio of downlink pilot, guard period, and uplink pilot periods, such as 6:1:7 or 7:1:6, to enable flexible UL/DL allocation and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed UL/DL configuration is used in LTE TDD, then system stability is maintained, but resource utilization efficiency deteriorates
Solution Approach 1:
The patent implements dynamic UL/DL configuration where the network can flexibly adjust the number and position of special subframes within a radio frame based on real-time traffic conditions. This allows the system to transition from static to dynamic resource allocation, improving resource utilization efficiency while maintaining system stability through controlled adaptation mechanisms.
Solution Approach 2:
The patent changes the parameter of special subframe configuration by allowing variable numbers of special subframes (e.g., 1, 2, or 3 per radio frame) and adjustable positions within the 10ms radio frame. This parameter flexibility enables the system to adapt to different traffic patterns while maintaining stable operation through standardized adjustment procedures.
2Reliability
If more special subframes are used for critical control information, then reliability of control signaling is improved, but available subframes for data transmission decrease
Solution Approach 1:
The patent dynamically adjusts the number of special subframes based on traffic conditions and control information requirements. When control reliability is prioritized, more special subframes are allocated; when data throughput is prioritized, fewer special subframes are used. This dynamic balancing resolves the contradiction between reliability and productivity.
Solution Approach 2:
The patent allows the parameter of special subframe count to be varied (1, 2, or 3 per radio frame) depending on system requirements. This parameter flexibility enables optimization of the balance between control information reliability and data transmission capacity according to real-time network conditions.
3Loss of time
If rigid UL/DL subframe allocation is implemented, then system complexity is reduced, but latency increases
Solution Approach 1:
The patent implements dynamic subframe allocation that adapts to traffic conditions to reduce latency for time-sensitive data. While this increases system complexity, the patent manages this through standardized procedures and network-controlled adjustments, balancing latency reduction with acceptable complexity levels.
Solution Approach 2:
The patent segments the radio frame into multiple configurable parts (downlink subframes, special subframes, uplink subframes) that can be independently adjusted. This segmentation allows flexible allocation to reduce latency for specific traffic types while maintaining overall system manageability through modular configuration.
Data Source
AI summary
Communications of a time division duplex radio frame provided with at least one special subframe including at least one pilot period is provided such that at least one special subframe is used for signalling of critical control information. Other subframes of the radio frame than the at least one special subframe are flexibly allocated for use as downlink and uplink subframes of the radio frame.