Over-the-air synchronization in multi-hop IAB networks
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Solution Overview
Problem
Traditional radio interface based synchronization techniques for next generation wireless networks are inefficient for multi-hop relay networks, as they rely on master nodes for timing synchronization, leading to error propagation and reduced spectral efficiency due to the need for muting patterns and degraded signal-to-interference-and-noise ratio (SINR) with increasing hop order.
Innovation Solution
Implementing a Precision Time Protocol (PTP) for over-the-air synchronization, where any network node can serve as a timing synchronization master, eliminating the need for master nodes and allowing nodes of higher hop order to synchronize directly with nodes of lower hop order, thereby improving SINR and spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional radio interface based synchronization techniques are used with master nodes, then timing synchronization can be established, but error propagation increases and spectral efficiency decreases due to muting patterns and degraded SINR with increasing hop order
Solution Approach 1:
The patent inverts the traditional master-node-centric synchronization architecture by allowing any network node to serve as a timing synchronization source for its child nodes. Instead of all relay nodes synchronizing to a single master node (causing error propagation), each node becomes a master for its own children, eliminating the hierarchical error accumulation and improving both synchronization reliability and spectral efficiency.
2Reliability
If master nodes are configured for timing synchronization in multi-hop relay networks, then synchronization can be provided, but the need for muting patterns reduces spectral efficiency
Solution Approach 1:
The patent implements self-service synchronization where each network node autonomously establishes timing synchronization with its parent node and subsequently serves as a synchronization master for its child nodes. This eliminates the need for centralized master node configuration and complex muting patterns, reducing network configuration complexity while maintaining synchronization reliability through distributed peer-to-peer synchronization.
3Measurement precision
If nodes of higher hop order synchronize with master nodes of hop order 0, then timing can be established, but SINR degrades with increasing hop order
Solution Approach 1:
The patent segments the synchronization path into local hop-by-hop synchronization relationships rather than a single long path from master node to distant relay nodes. Each node synchronizes with its immediate parent node, creating short localized synchronization segments that maintain high SINR. This segmentation prevents the cumulative signal degradation that occurs when nodes at high hop orders directly receive signals from distant master nodes.
Data Source
AI summary
An integrated access and backhaul network is provided with network nodes that can establish timing synchronization with any other network nodes. In an embodiment, network nodes in a multi-hop integrated access and backhaul network have a hop order of n, wherein n represents a number of hops from a node connected to the core network via a wired connection. In an embodiment, instead of using the network node with a hop order of 0 as the timing synchronization reference for over-the-air synchronization, any network node can use any other network node as a synchronization reference. A relay node can first establish a wireless link to said arbitrary node. Said wireless link is then used to synchronize the relay or IAB node using a Precision Time Protocol (PTP) implementation.