SSB Time-Domain Mapping for Orthogonal IAB and UE Synchronization
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Solution Overview
Problem
In current wireless communication systems, the discovery of Integrated Access and Backhaul (IAB) nodes is challenging due to half-duplex constraints, which prevent simultaneous transmission and reception of synchronization signal blocks (SSBs), leading to overlapping and non-orthogonal SSBs for IAB node discovery and user equipment (UE) initial access, especially when the number of SSBs exceeds the maximum allowed in a transmission period.
Innovation Solution
The method involves mapping candidate SSBs to a half-frame or time window with specific offsets and patterns, such as starting positions relative to the half-frame, mapping to consecutive sub-frames, and using predetermined rules to ensure orthogonality between SSBs for IAB node discovery and UE initial access, allowing for time division multiplexing to prioritize UE access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SSBs are transmitted without time domain mapping offsets, then transmission simplicity is maintained, but orthogonality between IAB node discovery SSBs and UE initial access SSBs is lost causing overlap
Solution Approach 1:
The patent applies parameter changes by introducing time domain mapping offsets (K1, K2) and mapping patterns for SSBs. These parameters control the time positions of SSBs in half-frames, enabling orthogonal separation between IAB node discovery SSBs and UE initial access SSBs. The offsets and patterns are configured based on subcarrier spacing and frequency range, dynamically adjusting time domain parameters to achieve orthogonality while maintaining systematic control.
2Adaptability or versatility
If the number of SSBs is increased to cover more directions, then discovery coverage is improved, but the maximum allowed SSBs in a transmission period is exceeded causing resource conflicts
Solution Approach 1:
The patent resolves the SSB quantity limitation by transitioning from a single half-frame dimension to multiple half-frames and time windows. SSBs that cannot be accommodated in one half-frame are mapped to subsequent half-frames or time windows, effectively adding temporal dimensions for SSB placement. This multi-dimensional time domain mapping allows the system to support a larger total number of SSBs for comprehensive directional coverage while respecting the per-transmission-period maximum constraints.
3Productivity
If SSBs for IAB node discovery and UE initial access are transmitted simultaneously, then transmission efficiency is maintained, but half-duplex constraints cause interference and reception failures
Solution Approach 1:
The patent applies segmentation by dividing SSB transmissions into distinct groups: SSBs for UE initial access and SSBs for IAB node discovery. These segmented SSB groups are assigned to different time domains (different half-frames or time windows) to eliminate simultaneous transmission conflicts. The segmentation enables independent optimization of each SSB group's timing while avoiding half-duplex interference, thus maintaining overall transmission efficiency without causing reception failures.
Data Source
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AI summary
A wireless communication method is described for a network node to determine time domain position of candidate synchronization signal blocks (SSBs) mapped to any one of a half-frame, a number of half-frames, and a time window associated with the half-frame, where the candidate SSBs are mapped with an offset relative to the half frame start position. The method also includes the network node transmitting one or more SSBs selected from the candidate SSBs to one or more network nodes.