PON Low-Delay Data Transmission via Reserved Slot Allocation
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Solution Overview
Problem
Passive optical networks (PONs) face challenges in efficiently transmitting data with different delay requirements, leading to high costs due to the need for additional infrastructure and reduced bandwidth utilization when trying to meet low-latency data transmission demands.
Innovation Solution
The method involves allocating independent low-frequency carrier frequency bands to each Optical Network Unit (ONU) for low-delay data transmission, allowing superposition on the frequency domain without interfering with primary traffic, and using amplitude control to prevent saturation of the Optical Line Terminal (OLT) receiver, enabling simultaneous transmission of low-delay and primary traffic without altering the existing network infrastructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic bandwidth allocation mechanism is used in PON, then bandwidth utilization is improved, but transmission delay increases
Solution Approach 1:
The patent segments the uplink transmission channel into two independent parts: a reserved slot for low-delay traffic and dynamic slots for primary traffic. This segmentation allows low-delay traffic to bypass the DBA scheduling process and be transmitted immediately in the reserved slot, while primary traffic continues to use dynamic bandwidth allocation. The reserved slot is positioned before the guard slot of primary traffic, ensuring isolation and preventing delay for time-sensitive data.
Solution Approach 2:
The patent implements preliminary action by pre-allocating a reserved slot in the uplink channel specifically for low-delay traffic before the actual data transmission occurs. This reserved slot is established in advance and does not require real-time scheduling decisions, allowing low-delay traffic to be transmitted immediately upon arrival without waiting for DBA scheduling, thus reducing transmission delay while maintaining overall system efficiency.
2Loss of time
If static bandwidth allocation is used to reduce delay, then transmission delay is reduced, but bandwidth utilization deteriorates
Solution Approach 1:
The patent segments the uplink bandwidth into a fixed reserved slot for low-delay traffic and dynamic slots for primary traffic. The reserved slot provides guaranteed low-delay transmission, while the remaining bandwidth is dynamically allocated to primary traffic based on actual demand. This segmentation ensures that delay-sensitive traffic gets priority access without permanently reserving excessive bandwidth that would remain idle during low traffic periods.
Solution Approach 2:
The patent changes the parameter of slot allocation from purely static or purely dynamic to a hybrid approach. The reserved slot position and basic structure remain fixed to ensure low-delay transmission, while the bandwidth allocation for primary traffic in other slots remains dynamic. This parameter change allows the system to maintain flexibility for primary traffic while providing deterministic low-delay paths for time-sensitive data.
3Loss of time
If additional wavelength channel is added for low-delay traffic, then transmission delay is reduced, but device complexity and cost increase
Solution Approach 1:
The patent merges low-delay traffic and primary traffic into the same uplink wavelength channel by allocating a reserved slot within the existing TDMA frame structure. Instead of creating a separate wavelength channel that would require additional optical path equipment, the invention combines both traffic types in one channel with differentiated slot allocations. This merging approach reduces system complexity and cost while still providing low-delay transmission paths.
Solution Approach 2:
The patent makes the existing uplink channel universal by enabling it to carry both low-delay traffic and primary traffic simultaneously through different slot allocations. The same optical path equipment and wavelength channel serve dual purposes: transmitting time-sensitive data in reserved slots and primary traffic in dynamic slots. This multi-functionality eliminates the need for separate dedicated infrastructure for low-delay traffic.
4Loss of time
If slot interval is reduced to reduce delay, then transmission delay is reduced, but signal interference increases
Solution Approach 1:
The patent segments the slot structure by placing the reserved slot for low-delay traffic immediately before the guard slot of primary traffic. This segmentation creates a clear boundary that prevents signal overlap and interference. The reserved slot is positioned at a specific location in the TDMA frame where it can transmit without waiting for primary traffic to complete, reducing delay while the guard slot structure maintains signal isolation and prevents harmful interference.
Data Source
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AI summary
Provided are a data transmission method and device and a storage medium. The method includes: acquiring a first type of data and a second type of data to be transmitted, where a transmission delay allowed by the first type of data is less than a transmission delay allowed by the second type of data; transmitting the first type of data required to be instantly transmitted on a first carrier frequency band of a transmission channel between a target optical network unit and an optical line terminal, where the transmission channel allows transmitting the first type of data and the second type of data at the same time, and on the transmission channel, a lowest frequency of a second frequency band for transmitting the second type of data is higher than a highest frequency in the first carrier frequency band.