CPRI Link Auto-Negotiation via Proxy Nodes in Ethernet Fronthaul
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Solution Overview
Problem
Current CPRI link negotiation processes, as specified in CPRI v7.0, are inadequate for Ethernet-based fronthaul networks, leading to discontinuity in establishing link bit rate negotiation, L1 synchronization, and frame synchronization/alignment between radio equipment controller (REC) and radio equipment (RE) due to the presence of intermediate Ethernet nodes operating at different rates, resulting in end-to-end CPRI link negotiation failures.
Innovation Solution
Implementing a method for CPRI link auto-negotiation in Ethernet-based fronthaul networks using a TLV-based out-of-band control protocol between Proxy Master and Proxy Slave nodes to facilitate link-rate negotiation subject to available bandwidth, ensuring that the negotiated link-rate does not exceed the available bandwidth, thereby preventing Loss of Signal (LOS)/Loss of Frame (LOF) states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CPRI link negotiation follows standard CPRI v7.0 processes, then link bit rate negotiation can be established between REC and RE, but discontinuity occurs in L1 synchronization and frame synchronization due to intermediate Ethernet nodes operating at different rates
Solution Approach 1:
The patent introduces Proxy Master and Proxy Slave nodes as intermediaries between REC and RE in the Ethernet-based fronthaul network. These proxy nodes perform CPRI to Ethernet mapping and participate in link-rate negotiation, enabling end-to-end CPRI link synchronization despite the presence of Ethernet infrastructure. The proxy nodes act as mediators that translate between CPRI and Ethernet protocols, resolving the synchronization discontinuity caused by intermediate Ethernet nodes.
2Ease of operation
If link-rate negotiation is performed without considering available bandwidth, then auto-negotiation can be completed, but Loss of Signal (LOS) andLoss of Frame (LOF) states occur when negotiated rate exceeds available bandwidth
Solution Approach 1:
The patent implements preliminary bandwidth assessment before link-rate negotiation. The Proxy Master and Proxy Slave nodes determine the available bandwidth between them prior to negotiating the CPRI link rate. This preliminary action ensures that the negotiated link rate does not exceed the available bandwidth, preventing LOS and LOF states while maintaining automatic negotiation capability.
Solution Approach 2:
The patent implements a feedback mechanism where the available bandwidth information is used to constrain the link-rate negotiation process. The negotiation algorithm receives feedback about the available bandwidth and adjusts the negotiated link rate accordingly, ensuring that the final agreed rate is within the capacity of the Ethernet infrastructure while still achieving automatic negotiation.
3Adaptability or versatility
If intermediate Ethernet nodes are introduced for fronthaul connectivity, then network flexibility and scalability are improved, but discontinuity in CPRI link negotiation and synchronization occurs
Solution Approach 1:
The patent segments the CPRI link establishment process into multiple phases: L1 synchronization between Proxy Master and Proxy Slave, link-rate negotiation through proxy nodes, and frame synchronization between REC and RE. This segmentation allows each phase to be handled appropriately for the Ethernet-based infrastructure while maintaining end-to-end CPRI link reliability.
Solution Approach 2:
The Proxy Master and Proxy Slave nodes perform multiple functions: they act as CPRI to Ethernet mapping devices, participate in link-rate negotiation, provide bandwidth assessment, and enable synchronization. This multi-functionality allows the network to maintain CPRI link reliability over Ethernet infrastructure, combining the flexibility of Ethernet with the reliability of CPRI synchronization.
Data Source
AI summary
The present disclosure is directed to directed to link-rate auto-negotiation between a radio equipment controller (REC) and a radio equipment (RE) in an Ethernet-based fronthaul network subject to bandwidth availability in the fronthaul network. In one aspect, a method includes determining, at a first proxy element in an Ethernet-based fronthaul network, that a new common public radio interface (CPRI) circuit is to be provisioned for packet exchange between a radio equipment control (REC) element and a radio equipment (RE) element of the Ethernet-based fronthaul network; performing, by at least one of the first proxy element and a second proxy element, an auto-negotiation for a link-rate for the new CPRI circuit, the link-rate being negotiated subject to a constraint, the constraint being an available bandwidth between the first proxy element and the second proxy element; and provisioning the new CPRI circuit with the link-rate.