Tunable Optical Network Unit Wavelength Configuration
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Solution Overview
Problem
Conventional Dynamic Bandwidth Allocation (DBA) algorithms in passive optical networks (PONs) introduce significant delay and packet delay variation, making them incompatible with real-time services enabled by 5G. Additionally, the high number of wavelengths in WDM systems increases complexity and cost due to the need for numerous spare parts and manual wavelength setting.
Innovation Solution
The development of a full-tunable Optical Network Unit (ONU) with a tunable receiver and transmitter, controlled by a processor and memory, allows for automatic setting of operating wavelengths without disrupting existing channels. This ONU can determine and set the correct wavelengths for both downstream and upstream communications, enabling dynamic reconfiguration of wavelength allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If full-tunable ONTs are used to reduce equipment variants, then adaptability improves, but device complexity increases due to the need for optical tunable filters and tunable lasers
Solution Approach 1:
The patent implements a universal transceiver design that can operate at multiple wavelengths (e.g., 1577nm, 1590nm, 1610nm, 1625nm) by integrating both a tunable laser and an optical tunable filter. This single device replaces what would traditionally require multiple fixed-wavelength transceivers, allowing the same hardware to serve multiple wavelength channels in the PON network.
Solution Approach 2:
The transceiver incorporates dynamically adjustable components - a tunable laser that can shift its emission wavelength and an optical tunable filter that can adjust its passband wavelength. These dynamic elements allow the transceiver to adapt its operating wavelength in real-time based on network configuration requirements, enabling flexible wavelength allocation without hardware changes.
2Manufacturing precision
If manual wavelength setting is used, then manufacturing precision is maintained, but ease of operation deteriorates due to increased installation time and requirement for specialized personnel
Solution Approach 1:
The system implements self-configuration capability where the ONU automatically determines its assigned wavelength through interaction with the OLT. The OLT sends downstream wavelength allocation information to the ONU, which then automatically configures its tunable laser and optical tunable filter to the correct wavelength without requiring manual intervention. This self-service approach maintains wavelength setting accuracy while dramatically simplifying installation procedures.
Solution Approach 2:
The configuration process uses feedback mechanisms where the ONU reports its status and wavelength capabilities to the OLT, and the OLT responds with wavelength allocation commands. This closed-loop feedback ensures that the wavelength setting is both automatic and accurate, with the system verifying that the ONU has correctly configured its components before allowing normal operation.
3Ease of operation
If automated configuration is implemented, then ease of operation improves, but reliability may deteriorate due to potential wavelength misconfiguration and rogue ONT issues
Solution Approach 1:
The automated configuration system incorporates multiple feedback checks to ensure reliability. The OLT verifies the ONU's wavelength capabilities before assignment, the ONU confirms successful wavelength configuration to the OLT, and the system monitors for proper wavelength operation. This multi-stage feedback process prevents misconfiguration and ensures that automatic wavelength setting maintains high reliability.
Solution Approach 2:
The system performs preliminary wavelength validation before final configuration. The OLT checks wavelength availability and compatibility with network conditions before assigning a wavelength to an ONU. The ONU also performs preliminary checks to ensure its tunable components can achieve the assigned wavelength. These preliminary actions prevent configuration errors before they occur, maintaining reliability while enabling automation.
4Adaptability or versatility
If a high number of wavelengths are used in WDM systems, then adaptability improves, but device complexity increases due to the need for numerous spare parts and manual wavelength setting
Solution Approach 1:
By deploying universal full-tunable transceivers that can operate at multiple wavelengths, the network reduces the variety of specialized equipment needed. Instead of requiring different fixed-wavelength transceivers for each wavelength channel, a single universal transceiver model can serve all wavelength assignments, significantly reducing spare parts inventory requirements and simplifying network operations.
Solution Approach 2:
The system dynamically changes the operating wavelength parameter of the transceiver based on network allocation rather than being fixed at manufacturing. This parameter flexibility allows the same hardware to adapt to different wavelength assignments, reducing the need for manual wavelength configuration and simplifying network operation and maintenance processes.
Data Source
AI summary
An optical network unit, ONU, (100) for a passive optical network, PON, comprising:a tunable receiver (110);a tunable transmitter (120); anda controller (130, 230) comprising a processor (132) and memory (134) containing instructions (136) executable by the processor whereby the ONU is operative to:if the tunable transmitter is on, switch the tunable transmitter off and if the tunable receiver is off, switch the tunable receiver on;determine a downstream control channel wavelength;set an operating wavelength of the tunable receiver to the downstream control channel wavelength;receive a downstream control channel signal at the downstream control channel wavelength from a central office, CO, node of the PON, the downstream control channel signal carrying an indication of an allocation of channel wavelengths to ONUs;obtain allocated downstream and upstream channel wavelengths for the ONU from the indication of an allocation of channel wavelengths to ONUs;set an operating wavelength of the tunable receiver to the allocated downstream channel wavelength and set the operating wavelength of the tunable transmitter to the allocated upstream channel wavelength; andswitch the tunable transmitter on.