IAB Node Timing Control Using Dual Offset Adjustment
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Solution Overview
Problem
Current integrated access and backhaul (IAB) systems face challenges in synchronizing and timing alignment, particularly in frequency division multiplexing (FDM) and spatial division multiplexing (SDM) scenarios, which can lead to issues like power imbalance and inter-symbol interference, and require efficient duplexing scheme control and smooth coexistence of different timing approaches.
Innovation Solution
The implementation of two offset values for timing adjustment, where offset 1 is based on legacy timing advance control for TDM and offset 2 aligns MT TX with DU TX for SDM/FDM, allowing for implicit adjustment of MT UL transmission timing based on IAB resource configuration, and explicit signaling to select between these offsets depending on duplexing modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If legacy timing advance control is used for TDM, then timing alignment is achieved for time division multiplexing, but it cannot provide proper timing alignment for FDM and SDM scenarios
Solution Approach 1:
The patent implements dynamic timing offset adjustment where the IAB node can switch between first offset (for TDM) and second offset (for FDM/SDM) based on the duplexing mode. This dynamic adaptation allows the same hardware to efficiently handle multiple timing scenarios without requiring separate dedicated mechanisms for each mode.
Solution Approach 2:
The patent changes the timing parameter by introducing two distinct offset values: a first offset for TDM operations and a second offset for FDM/SDM operations. The appropriate offset is selected based on the duplexing mode, enabling proper timing alignment across different operational scenarios without increasing hardware complexity.
2Measurement precision
If separate timing approaches are used for different duplexing modes, then accurate timing alignment is achieved, but coordination complexity and signaling overhead increase
Solution Approach 1:
The patent creates a universal timing control mechanism where a single IAB node implements both first offset and second offset capabilities. The node universally applies the appropriate offset based on duplexing mode indicators, eliminating the need for separate coordination mechanisms for different timing approaches while maintaining high timing alignment accuracy.
Solution Approach 2:
The IAB node autonomously determines which offset to apply by monitoring duplexing mode indicators in resource configurations. The node self-adjusts its timing without requiring external coordination or complex signaling, reducing overall system complexity while maintaining precise timing alignment.
3Reliability
If guard period is extended to cover all timing uncertainties, then timing safety is improved, but overhead and resource efficiency deteriorate
Solution Approach 1:
The patent reduces guard period overhead by changing the timing parameter through precise offset adjustment. By accurately aligning MT UL transmission timing with DU TX timing using the appropriate offset, the system minimizes timing uncertainties, allowing for shorter guard periods while maintaining reliability.
Solution Approach 2:
The system uses feedback from duplexing mode indicators to dynamically adjust timing offsets. This feedback mechanism ensures that the correct offset is applied based on current operational mode, reducing timing uncertainties and enabling optimized guard period lengths that balance reliability and resource efficiency.
Data Source
AI summary
Systems, methods, apparatuses, and computer program products for the synchronization and timing of IAB nodes are provided. One method may include determining, at a parent node, a resource configuration and using the determined resource configuration to set a timing advance (TA) mode with two offsets comprising a first offset to be used with time division multiplexing (TDM) and a second offset to be used with at least one of spatial division multiplexing (SDM) or frequency division multiplexing (FDM). The method may also include transmitting a command, to an integrated access and backhaul (IAB) node, to start adjusting mobile termination (MT) uplink (UL) transmission (Tx) timing based on the resource configuration and the timing advance (TA).