Proxy Node Link Fault Handling in 5G Fronthaul Networks
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Solution Overview
Problem
In unified Ethernet-based 5G fronthaul systems, conventional methods for handling link faults such as loss of signal (LOS), loss of frame (LOF), and line code violations (LCV) are inefficient, leading to prolonged downtime and communication disruptions due to the lack of effective fault propagation and synchronization across proxy nodes.
Innovation Solution
The proposed solution involves proxy nodes that detect link faults and delay their transition to Layer 1 synchronization, allowing end-to-end fault alarm information to propagate, and using variable or fixed-sized extension headers to communicate fault information, enabling synchronized resynchronization of REC, RE, and proxy nodes, thus maintaining continuous communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fault handling methods are used in fronthaul networks, then fault detection capability is maintained, but resynchronization time is prolonged and network downtime increases
Solution Approach 1:
The patent applies preliminary action by having proxy nodes delay their transition to Layer 1 synchronization state until fault alarm information has propagated end-to-end through the network. This preliminary waiting period ensures that all nodes receive fault notifications before resynchronization begins, preventing premature resynchronization attempts that would fail and extend downtime.
Solution Approach 2:
The patent implements feedback mechanisms through extension headers that carry fault alarm information from detecting nodes to remote equipment. The feedback loop ensures that fault status is communicated throughout the network, and resynchronization is triggered only when appropriate feedback confirms that fault conditions have been acknowledged by all relevant nodes.
2Speed
If immediate Layer 1 synchronization transition is performed upon fault detection, then resynchronization starts quickly, but fault alarm information fails to propagate end-to-end causing communication disruptions
Solution Approach 1:
The patent uses preliminary action by delaying the Layer 1 synchronization transition until fault alarm information has had time to propagate through the entire network path. This ensures that fault notifications reach remote equipment before resynchronization begins, preventing information loss and communication disruptions while maintaining acceptable resynchronization speed.
Solution Approach 2:
The patent introduces extension headers as intermediaries that carry fault alarm information between detecting nodes and remote equipment. These headers act as mediators that ensure fault information is transmitted reliably through the network infrastructure, bridging the gap between fault detection and resynchronization initiation.
3Productivity
If proxy nodes immediately transition to Layer 1 synchronization state, then individual node resynchronization is fast, but network-wide synchronization coordination is lost leading to prolonged downtime
Solution Approach 1:
The patent merges the resynchronization actions of multiple proxy nodes by coordinating their Layer 1 synchronization transitions through shared fault alarm information. Instead of nodes acting independently, the extension headers ensure all nodes receive the same fault notification and transition to synchronization state simultaneously, maintaining network-wide synchronization stability while preserving individual node efficiency.
Solution Approach 2:
The patent uses feedback through extension headers to coordinate network-wide synchronization. The fault alarm information propagates to all proxy nodes, providing feedback that triggers synchronized resynchronization actions across the entire network, preventing coordination loss and ensuring stable network state transitions.
Data Source
AI summary
In a fronthaul network system, when a CPRI link fault is detected at either of the REC or RE, both the REC and RE perform a Layer 1 synchronization. The fault may be a loss of signal, loss of frame, or a line code violation, which also translates to a loss of signal if seen beyond a threshold. A proxy slave recognizes the fault in a CPRI signal from a first radio device and inserts the fault alarm into a header of a radio over Ethernet frame. The proxy slave continues to communicate the signal for a configured number of hyper-frames. A proxy master receives the signal and communicates the signal and the fault alarm to a receiving radio device for a configured number of hyper-frames. The proxy and radio devices all perform a joint resynchronization.