RFoG Upstream Scheduling via Virtual MAP Replication
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Solution Overview
Problem
RFoG networks face challenges in managing multiple upstream scheduling due to the possibility of Optical Beat Interference from simultaneous upstream transmissions, as existing DOCSIS scheduling methods are inadequate for handling analog RF signals over fiber.
Innovation Solution
The implementation of a virtual MAP message system that configures and replicates bandwidth allocations across multiple upstream channels, ensuring temporal alignment and avoiding collisions by using a scheduler to allocate virtual channels and replicate MAP messages, allowing multiple channels to transmit simultaneously while preventing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple upstream channels are used to increase bandwidth capacity, then data throughput is improved, but Optical Beat Interference occurs due to simultaneous transmissions
Solution Approach 1:
The system performs preliminary scheduling by replicating MAP messages to multiple upstream channels before actual transmission occurs. The scheduler pre-allocates time slots and bandwidth across all upstream channels, ensuring that ONUs are assigned to specific channels in advance. This preliminary coordination prevents simultaneous transmissions and Optical Beat Interference before they can occur, while still allowing multiple channels to operate concurrently for high throughput.
2Adaptability or versatility
If existing DOCSIS scheduling methods are used for RFoG networks, then backward compatibility is maintained, but collisions occur due to inadequate handling of analog RF signals
Solution Approach 1:
The system creates a universal scheduling mechanism that works across both traditional DOCSIS channels and RFoG upstream channels. By replicating MAP messages to multiple upstream channels with different center frequencies, the system maintains compatibility with existing DOCSIS scheduling protocols while extending functionality to handle analog RF signals. This multi-functional approach allows the same scheduler to manage both legacy and new channel types without requiring separate scheduling systems, thereby maintaining reliability while ensuring compatibility.
3Productivity
If bandwidth is allocated to multiple ONUs simultaneously, then system efficiency is improved, but collisions and signal degradation occur
Solution Approach 1:
The system segments the upstream bandwidth allocation by assigning specific time slots and frequency channels to individual ONUs. Through MAP message replication, each ONU receives a dedicated allocation for specific upstream channels during specific time periods. This segmentation ensures that only one ONU transmits at a time on any given channel, eliminating collisions and signal degradation while maintaining high system efficiency through parallel operations across multiple segmented time-frequency slots.
Data Source
AI summary
A method for use in an RFoG cable network calls for allocating upstream bandwidth to CM devices, wherein allocating bandwidth includes selecting a start time and allocating respective time slots relative to the selected start time to at least one of the requesting CM devices; and further, allocating the same timeslots over multiple selected upstream channels, thereby aligning upstream transmissions from the requesting CMs across the selected upstream channels. Several embodiments are disclosed to enable DOCSIS 3.0 type scheduling over an RFoG network.