IAB Node Timing Alignment for Cross-Link Interference Control
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Solution Overview
Problem
The operation of Integrated Access and Backhaul (IAB) nodes in 5G networks is hindered by the need to improve resource multiplexing and control timing alignment to avoid cross-link interference, particularly in scenarios where neighboring cells have different UL-DL switch points.
Innovation Solution
A method for determining and adjusting transmit times of data on both backhaul and access links using reference signals, accounting for time shifts and slot differences to calculate timing errors, ensuring simultaneous data transmission within predefined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If IAB nodes transmit data on backhaul and access links simultaneously, then resource utilization is improved, but timing misalignment causes cross-link interference
Solution Approach 1:
The patent implements a feedback mechanism where the network entity receives timing information from the IAB node about the difference between backhaul and access link transmit times. Based on this feedback, the network entity sends timing adjustment commands to the IAB node, enabling continuous refinement of timing alignment and elimination of cross-link interference while maintaining simultaneous transmission capability
Solution Approach 2:
The patent adjusts the timing parameter (transmit time difference) between backhaul and access links by calculating a timing adjustment value based on measured timing differences. This parameter change aligns the transmit times of both links, eliminating interference while preserving the benefits of simultaneous transmission for improved resource utilization
2Object-affected harmful factors
If IAB nodes align transmit times of backhaul and access links, then cross-link interference is reduced, but timing measurement and adjustment complexity increases
Solution Approach 1:
The patent introduces a network entity as an intermediary that centralizes the timing measurement and adjustment functions. Instead of requiring complex distributed timing synchronization between multiple IAB nodes, the network entity performs centralized timing measurements and sends adjustment commands, simplifying the overall system architecture while achieving interference reduction
3Measurement precision
If IAB nodes use different time slots for backhaul and access links, then timing alignment is improved, but resource utilization efficiency decreases
Solution Approach 1:
The patent implements dynamic timing adjustment where the transmit times of backhaul and access links are continuously optimized based on measured timing differences. This dynamic approach allows the system to achieve precise timing alignment without being constrained to fixed different time slot assignments, thereby maintaining high resource utilization efficiency while improving timing alignment precision
Data Source
AI summary
The present subject matter relates to a method for operating a node of a communication system. The node is configured to support wireless backhauling in the communication system and support wireless access in the communication system. The method comprises: receiving from a node first data on a backhaul link and second data on an access link, determining transmit times of the first and second data using the received first data and second data, determining a timing error using the determined transmit times.