Dynamic TDD Configuration Switching for Ultra-Low Latency
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Solution Overview
Problem
Current LTE/LTE-Advanced systems face challenges in achieving low latency and supporting wider system bandwidths, particularly in high frequency bands above 6 GHz, which are necessary for advanced applications like 3D streaming and real-time virtual physical experiences, due to limitations in Time Division Duplex (TDD) configurations and Hybrid Automatic Repeat Request (HARQ) round-trip times.
Innovation Solution
The proposed solution involves optimizing TDD UL/DL configurations with increased system bandwidth, reduced guard period overhead, and flexible slot durations to accommodate various traffic ratios, allowing for ultra-low latency operations by configuring different radio frame structures and switching between them dynamically, ensuring average periodicity of switching between transmission and reception modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If TDD configurations are optimized with reduced guard period overhead and flexible slot durations, then latency is reduced, but system complexity increases due to dynamic configuration switching
Solution Approach 1:
The patent implements dynamic TDD configuration switching between different radio frame structures (first configuration with longer slot duration and second configuration with shorter slot duration) based on traffic conditions. This allows the system to adaptively optimize latency for time-sensitive applications while maintaining compatibility with existing LTE infrastructure, resolving the contradiction between reduced latency and system complexity.
Solution Approach 2:
The patent segments the transmission time into different slot durations within the same radio frame structure. By dividing the transmission timeline into variable-length slots (first slot duration for normal traffic, second shorter slot duration for low-latency traffic), the system can handle different traffic types with appropriate timing without requiring complete system redesign.
2Productivity
If system bandwidth is increased to support higher data rates, then data rate is improved, but HARQ round-trip time increases
Solution Approach 1:
The patent dynamically switches between different TDD configurations based on traffic requirements. When low-latency traffic is detected, the system transitions to a configuration with shorter slot durations, which reduces HARQ round-trip time even when operating with increased system bandwidth. This dynamic adaptation allows the system to simultaneously support high data rates and low latency for different application types.
3Loss of time
If guard period is reduced to increase transmission time, then latency is reduced, but reliability decreases due to insufficient switching time
Solution Approach 1:
The patent segments the transmission structure into different slot types with different guard period requirements. Normal slots maintain adequate guard periods for reliable switching, while shortened slots for low-latency traffic are designed with modified guard period structures that still ensure sufficient transmit-to-receive switching time. This segmentation allows latency reduction without compromising the reliability of mode switching.
Data Source
AI summary
Radio frame configuration circuitry for use in a device of a wireless communication system is provided. The radio frame configuration circuitry uses control circuitry to select between a plurality of different time-division duplex, TDD, configurations for a radio frame having slots with a configured duration. Transceiver circuitry performs TDD communications based on selections made by the control circuitry such that an average periodicity of switching between transmission of information and reception of information during the TDD communication is the same despite switching between different ones of the plurality of different TDD configurations. The radio frame configuration circuitry can be incorporated in a UE or an eNodeB or a Peer Radio Head. A corresponding method is provided.