Hybrid Synchronization for TDD Interference Minimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for coexistence in TDD bands face challenges due to strict time synchronization requirements, which restrict flexibility in allocating time resources and lead to reduced spectrum efficiency, especially when coexisting with different technologies or systems that cannot be modified.
Innovation Solution
A hybrid synchronization scheme is proposed, where downlink transmissions are strictly synchronized, while uplink operations are asynchronous, allowing flexible UL:DL patterns without requiring changes to incumbent systems, and minimizing interferences between systems and within the same system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If strict time synchronization scheme is implemented to minimize interferences between TDD systems, then interference reduction is improved, but flexibility in time resource allocation deteriorates
Solution Approach 1:
The patent segments the transmission opportunities into distinct downlink slots and uplink slots with clear time separation. By dividing the TDD frame into dedicated downlink periods and uplink periods, the system achieves interference reduction while maintaining flexibility through configurable slot allocations that can adapt to different traffic patterns without requiring strict synchronization across multiple systems.
Solution Approach 2:
The patent implements dynamic time resource allocation where the base station can flexibly configure the number and distribution of downlink and uplink slots based on actual traffic demands. This dynamic adjustment capability allows the system to adapt UL:DL ratios in real-time while avoiding the need for strict time synchronization with other systems, thus resolving the contradiction between interference reduction and allocation flexibility.
2Object-affected harmful factors
If strict UL:DL pattern is imposed to ensure coexistence between systems, then interference minimization is improved, but ability to cope with varying traffic types deteriorates
Solution Approach 1:
The patent enables dynamic adjustment of UL:DL patterns by allowing the base station to configure different numbers of downlink slots and uplink slots based on traffic characteristics. This dynamic configuration capability permits the system to adapt to varying traffic types (e.g., voice over IP versus high-quality video) while maintaining coexistence through clear time separation that minimizes cross interference between different systems.
Solution Approach 2:
The patent changes the parameters of time resource allocation by allowing flexible configuration of slot durations, numbers, and distributions. This parameter flexibility enables the system to optimize performance for different traffic types while maintaining interference minimization through proper time division, thus resolving the contradiction between fixed patterns and adaptive traffic handling.
3Manufacturing precision
If timing advance mechanism is introduced to compensate propagation delays, then uplink transmission alignment is improved, but system complexity increases
Solution Approach 1:
The patent extracts the timing advance mechanism from the synchronization protocol by handling propagation delays independently through base station scheduling. Instead of requiring all systems to synchronize and adjust their timing simultaneously, the base station individually manages uplink alignment for each user equipment, simplifying the overall system complexity while maintaining transmission alignment precision.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method and device for optimal coexistence of a first cellular Time-Division Duplex, TDD, system and a second TDD system operating in the same frequency band. The proposed solution is capable of minimizing interferences without modifying the (RF and SW) characteristics of the second system, while at the same time achieving flexibility in UL:DL traffic ratio.