Title : Optical Auto-Negotiation

Background:

In today's telecommunications landscape, Radio Access Networks (RAN) are often deployed in brownfield environments where a mix of Common Public Radio Interface (CPRI) and Ethernet-based fronthaul systems coexist. Unlike data center deployments, these setups lack dedicated management infrastructure and fiber, demanding robust auto-negotiation capabilities to detect and adapt to different interface speeds and technologies, such as Forward Error Correction (FEC) schemes.

Currently, CPRI version 7 provides a standardized method for auto-detection by cycling through potential combinations at varying rates on each end of the link. However, this approach has limitations. It may not converge when more than four speed and technology combinations are possible and places significant demands on the Host System On a Chip (SOC) and SERDES for reconfiguration and adaptation. Additionally, current methods do not account for the potential use of breakout cables, which may become prevalent in future fronthaul deployments.

The objective of this master thesis is to explore and create an optical auto-negotiation protocol that overcomes the limitations of current methods in heterogeneous fronthaul networks. The thesis will aim to enhance convergence reliability, minimize system demands, and ensure compatibility with existing and future hardware and technologies, such as breakout cables. Additionally, the research is expected to generate valuable contributions to industry consortiums and standard organizations, potentially influencing future telecommunications standards and practices.

Key Steps:

Investigate and Identify Optical Technologies:

Conduct a comprehensive review of common optical technologies applicable in Ericsson RAN, covering past, present, and potential future technologies.

Evaluate Optical Technologies for OAN Signaling:

Analyze how the identified optical technologies can handle low baud rate optical auto-negotiation (OAN) signaling based on current electrical auto-negotiation schemes in Intensity Modulation Direct Detection (IMDD) and coherent systems.

Propose OAN Protocol and Implementation:

Develop proposals for replacing CPRI line rate negotiation with an OAN next page function. Design a new protocol and outline implementation options, including the development of an additional state machine for OAN.

Test OAN on FPGA Platform:

Implement and validate the proposed OAN protocol on an FPGA platform to assess its practicality and performance in a controlled environment.

Present Findings to MOPA:

Compile and present the gathered data in a presentation to the MOPA (Management of Optical Products and Applications) group for review and feedback.

Contribute to Future IEEE 802.3 NEA Activities:

Prepare and present the findings as part of future Ericsson contributions to the IEEE 802.3 New Ethernet Applications (NEA) group, focusing on the topic of OAN.

Engage with Optical Vendors for Feedback:

Utilize the MOPA optical auto-negotiation forum as a platform to engage with optical vendors and gather feedback on the proposed solutions and their feasibility.