CPRI Fronthaul Link Negotiation Through Proxy Node Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current CPRI link negotiation processes prescribed by CPRI Specification v7.0 do not work in fronthaul networks due to the presence of intermediate Ethernet nodes, leading to discontinuity issues in establishing end-to-end CPRI link negotiation between radio equipment controller (REC) and radio equipment (RE), as these nodes operate at different rates, making manual static configurations error-prone and inefficient.
Innovation Solution
Implementing a mechanism for CPRI link establishment in Ethernet-based fronthaul networks by configuring proxy slave and proxy master nodes to perform CPRI mapping/de-mapping and using RoE frames with enhanced headers to convey link bit rate information, enabling end-to-end CPRI link synchronization through Layer 1 auto-negotiation operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual static configurations are used for CPRI link establishment in fronthaul networks, then link establishment can be achieved, but the process becomes error-prone and inefficient
Solution Approach 1:
The system enables automatic CPRI link negotiation between REC and RE through intermediate Ethernet nodes. The proxy nodes perform automated rate matching and link synchronization without requiring manual static configuration, allowing the system to self-establish connections dynamically based on current network conditions
Solution Approach 2:
Proxy nodes (proxy master and proxy slave) are introduced as intermediaries between REC and RE. These intermediaries perform CPRI mapping/de-mapping, rate adaptation, and link negotiation functions, enabling automatic link establishment while handling the complexity of rate matching between different CPRI interfaces
2Adaptability or versatility
If intermediate Ethernet nodes are introduced in fronthaul networks, then network flexibility and scalability are improved, but discontinuity issues arise in CPRI link negotiation
Solution Approach 1:
The proxy nodes serve as intermediaries that bridge the discontinuity introduced by Ethernet nodes. They perform CPRI to Ethernet mapping and vice versa, maintaining synchronization state information, and ensuring continuous link negotiation despite the packetized nature of Ethernet transport
Solution Approach 2:
The system dynamically adjusts CPRI link parameters (bit rates, frame structures) to match the capabilities of intermediate Ethernet nodes. The proxy nodes negotiate and adapt parameters such as link rate and hyper frame number synchronization to maintain continuous operation across heterogeneous network elements
3Reliability
If CPRI link auto-negotiation is performed through intermediate proxy nodes, then end-to-end synchronization is achieved, but additional complexity is introduced in the network architecture
Solution Approach 1:
The end-to-end CPRI link negotiation is segmented into multiple stages: REC to proxy master, proxy master to proxy slave, and proxy slave to RE. Each segment negotiates independently with intermediate state synchronization, breaking down the complex end-to-end problem into manageable segments that can be handled by individual nodes
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Techniques that provide link establishment between a radio equipment controller (REC) and a radio equipment (RE) in a fronthaul network are described herein. In one embodiment, a method includes performing, Common Public Radio Interface (CPRI) Layer 1 (Ll) link auto-negotiation operations to establish a CPRI link between the REC and RE. A proxy slave may achieve a hyper frame number (HFN) synchronization with the REC at a link bit rate for a first CPRI bit stream and communicate the first CPRI bit stream and the link bit rate to a proxy master. The proxy master may communicate a second CPRI bit stream to the proxy slave to transmit to the REC. The Ll link auto-negotiation operations are completed and CPRI link is established between the REC and the RE when the REC achieves a HFN synchronization for the second CPRI bit stream.