Passive Optical Network Framing Method for Optical Power Budget
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Solution Overview
Problem
The existing passive optical network (PON) systems face challenges in maintaining an adequate optical power budget due to increasing optical link losses, which affects the performance and efficiency of data transmission.
Innovation Solution
The proposed solution involves generating separate transmission convergence frames with different downstream rates (2.488 Gbps or 10 Gbps) and performing bit mapping, coding, and scrambling to create a third frame that can be sent to optical network units (ONUs), thereby reducing optical link losses and increasing the optical power budget without requiring significant network reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single high-rate downstream frame is used, then data transmission speed is improved, but optical link loss increases and optical power budget becomes insufficient
Solution Approach 1:
The patent divides the downstream data stream into multiple frames with different bit rates. Specifically, it segments the data into a first frame at 2.488 Gbps and a second frame at 1.244 Gbps (or other lower rates), allowing the system to transmit data at high speed when needed while also maintaining lower-rate transmissions that consume less optical power and reduce link loss.
Solution Approach 2:
The patent changes the bit rate parameter of transmission frames dynamically. By transmitting some frames at 2.488 Gbps and others at lower rates (1.244 Gbps, 622 Mbps, etc.), the system adapts the transmission parameters to balance between achieving high data transmission speed and minimizing optical link loss, thereby optimizing the optical power budget.
2Length of stationary object
If optical link loss is reduced to increase optical power budget, then transmission distance is improved, but data transmission rate may be reduced
Solution Approach 1:
The patent segments the data transmission into multiple frames with different bit rates. By including both high-rate frames (2.488 Gbps) and low-rate frames (1.244 Gbps or lower), the system can extend transmission distance using the lower-rate frames that are more tolerant of optical link loss, while still maintaining high data transmission rates for portions of the data stream.
Solution Approach 2:
The patent dynamically changes the bit rate parameter across different frames to balance transmission distance and data rate. Lower bit rate frames can be transmitted over longer distances with acceptable signal quality, while higher bit rate frames provide fast data transmission when the optical link conditions permit, thus optimizing both transmission distance and overall data transmission rate.
3Adaptability or versatility
If the network is reconstructed to accommodate different bit rates, then system adaptability is improved, but device complexity and reconstruction cost increase
Solution Approach 1:
The patent implements a universal frame structure that can carry data at multiple bit rates (2.488 Gbps, 1.244 Gbps, 622 Mbps, etc.) within the same PON network infrastructure. The OLT and ONU devices maintain their existing hardware configurations but gain the capability to handle variable bit rate frames through protocol-level modifications, achieving multi-functionality without requiring separate hardware for each bit rate.
Solution Approach 2:
The patent introduces dynamic bit rate adjustment at the frame level, where the OLT can dynamically select which bit rate to use for each frame based on network conditions, ONU capabilities, and service requirements. This dynamic approach allows the existing network infrastructure to adapt to different transmission scenarios without physical reconstruction, as the adaptability is achieved through flexible frame generation and processing logic.
Data Source
Figure 1~2A
Figure 2B~3
Figure 4A~4C
AI summary
The present invention discloses a framing method and apparatus in a passive optical network and a system. The method includes: generating a first gigabit-capable passive optical network transmission convergence TC frame and a second TC frame separately, where a sum of frame lengths of the first TC frame and the second TC frame is 125 microseconds, and an interval between frame headers of second TC frames is 125 microseconds; performing bit mapping on the second TC frame to generate a third TC frame, where the bit mapping refers to identifying each bit of the second TC frame by using N bits; and sending the first TC frame and the second TC frame to an optical network unit. In the framing method, a line rate corresponding to the second TC frame is lower than 2.488 Gbps, so that a rate of a receiver on a receiving side is decreased and a bandwidth of the receiver is narrowed, thereby decreasing an optical link loss and increasing an optical power budget.