WDM Aggregation Node for 5G CRAN Transport
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Solution Overview
Problem
The reuse of Gigabit Passive Optical Network (GPON) infrastructure for Centralized/Cloud Radio Access Network (CRAN) in 5G communication networks faces challenges such as bandwidth limitations, delay asymmetry, unpredictable latency, and distance limitations, making it impractical for fronthaul and backhaul purposes.
Innovation Solution
A method involving first and second level aggregation nodes and a Passive Optical Network, where WDM channels with wavelengths in a first spectrum section are combined with passive optical channels in a different spectrum section, allowing for efficient forwarding and termination of signals in a transport network, bypassing the Optical Line Terminal (OLT) and enabling flexible wavelength allocation and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If GPON infrastructure is reused for CRAN fronthaul and backhaul, then existing infrastructure can be utilized, but bandwidth limitations and delay asymmetry occur
Solution Approach 1:
The patent introduces wavelength division multiplexing (WDM) to add a spectral dimension to the existing GPON infrastructure. By transmitting multiple optical channels at different wavelengths simultaneously over the same fiber, the system achieves bandwidth expansion without requiring additional fiber cables, thus resolving the contradiction between infrastructure reuse and bandwidth requirements
Solution Approach 2:
The patent creates a multi-functional transport network that can simultaneously handle both traditional GPON traffic and CRAN fronthaul/backhaul traffic. The WDM-based architecture allows a single optical fiber to carry multiple types of traffic with different requirements, making the infrastructure universal and eliminating the need for separate dedicated networks
2Ease of manufacture
If GPON infrastructure is used for CRAN, then infrastructure cost is reduced, but distance limitations and unpredictable latency occur
Solution Approach 1:
By utilizing the wavelength dimension through WDM technology, the patent enables extended transmission distances. Different wavelength channels can be optimized for different transmission characteristics, allowing the network to reach farther distances while maintaining signal quality and reducing latency variability
Solution Approach 2:
The patent changes key transmission parameters by introducing WDM channels with specific wavelength assignments. This allows optimization of transmission distance and latency characteristics for different traffic types, enabling the network to overcome the distance limitations of traditional GPON while keeping infrastructure costs low
3Quantity of substance
If WDM channels are combined with passive optical channels, then bandwidth and distance requirements are met, but device complexity increases
Solution Approach 1:
The patent segments the network into distinct functional layers: the WDM transport layer for high-bandwidth fronthaul/backhaul and the GPON access layer for last-mile connectivity. This segmentation allows each layer to be optimized independently, managing complexity by separating concerns while maintaining high bandwidth capabilities
Solution Approach 2:
The patent introduces WDM multiplexers/demultiplexers as intermediary devices that bridge the GPON infrastructure and CRAN requirements. These intermediaries enable the combination of passive optical channels with active WDM channels without requiring complete redesign of the existing network, thus managing complexity while achieving bandwidth and distance goals
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables the efficient transport of high-bandwidth signals over longer distances, addressing bandwidth and latency issues, and allows for dynamic reconfiguration of traffic, thereby supporting the requirements of 5G networks without requiring significant changes to existing GPON infrastructure.
Implementation Method 1
receiving, from the second level aggregation node, a plurality of wavelength division multiplexing (WDM) channels having wavelengths in a first spectrum section and generating at least one passive optical channel having a wavelength in a second spectrum section, different to the first spectrum section. The method further comprises combining at least some of the WDM channels received from the second level aggregation node with the at least one passive optical channel
Data Source
AI summary
A method in a first level aggregation node of a transport network is disclosed. The transport network comprises the first level aggregation node, a second level aggregation node and a Passive Optical Network. T the method comprises receiving, from the second level aggregation node, a plurality of wavelength division multiplexing (WDM) channels having wavelengths in a first spectrum section and generating at least one passive optical channel having a wavelength in a second spectrum section, different to the first spectrum section. The method further comprises combining at least some of the WDM channels received from the second level aggregation node with the at least one passive optical channel, and forwarding the combined WDM channels and passive optical channel to a termination node in the Passive Optical Network. Also disclosed are a method in a termination node of a transport network, a first level aggregation node, a termination node and a computer program.