OFDMA Passive Optical Network Architecture for Long Distance Transmission
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Solution Overview
Problem
Current PON systems, such as TDM-based GE-PON and 10 G-PON, face challenges in supporting heterogeneous services over long distances due to complex scheduling algorithms, high system costs, and limited flexibility in bandwidth allocation, while WDM-PON lacks dynamic bandwidth allocation among optical network units.
Innovation Solution
The implementation of an OFDMA-based passive optical network architecture that allows multiple signals to be received simultaneously at different wavelengths, enabling transparent support for various applications and dynamic bandwidth allocation in two-dimensional frequency and time space, using an optical line terminal with OFDMA to facilitate simultaneous operation of multiple transmitters during one upstream time slot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If TDM-based GE-PON and 10 G-PON networks are used to support heterogeneous services, then service diversity is improved, but device complexity increases due to complex scheduling algorithms and framing technology
Solution Approach 1:
The patent segments the bandwidth into multiple orthogonal subcarriers (e.g., 128 subcarriers) that can be independently allocated to different ONUs. This frequency-domain segmentation eliminates the need for complex time-domain scheduling algorithms, as each subcarrier acts as an independent transmission channel that can be dynamically assigned based on demand.
Solution Approach 2:
The patent transitions from traditional one-dimensional time-division multiplexing to two-dimensional frequency-time resource allocation. By introducing the frequency dimension through orthogonal subcarriers, the system achieves flexible bandwidth allocation without complex scheduling, as resources can be allocated simultaneously across multiple frequencies and time slots.
2Speed
If 10 G-PON systems are deployed to achieve high data rates, then transmission speed is improved, but system costs increase due to expensive 10 Gb/s components
Solution Approach 1:
The patent merges multiple lower-speed transmission channels (subcarriers) to achieve high aggregate data rates. Instead of using a single expensive 10 Gb/s component, the system combines 128 subcarriers each operating at lower speeds (e.g., 2.5 GHz components), achieving 10 Gb/s throughput through parallel processing while using more cost-effective hardware.
Solution Approach 2:
The patent changes the operating parameters by using lower-frequency components (2.5 GHz instead of 10 Gb/s) and distributing the bandwidth across multiple subcarriers. This parameter transformation allows the system to achieve high data rates through parallel low-speed channels rather than requiring expensive high-speed single-mode components.
3Use of energy by moving object
If WDM-PON is used to provide wavelength division multiplexing, then spectral efficiency is improved, but flexibility in dynamic bandwidth allocation among ONUs is reduced
Solution Approach 1:
The patent implements dynamic bandwidth allocation by allowing the OLT to flexibly assign different numbers and combinations of subcarriers to different ONUs based on real-time traffic demands. The system can dynamically adjust the allocation from 1 to 128 subcarriers per ONU, providing granular control and adaptability that static WDM-PON configurations cannot achieve.
4Length of stationary object
If traditional PON architectures are used to support long distance transmission, then transmission distance is improved, but data rate capability deteriorates due to limited spectral efficiency
Solution Approach 1:
The patent overcomes the distance-rate tradeoff by introducing frequency-domain multiplexing through orthogonal subcarriers. This dimensional transformation allows multiple low-speed channels to operate simultaneously over long distances, achieving high aggregate data rates (10 Gb/s) while maintaining extended reach without requiring expensive 10 Gb/s components for each channel.
Data Source
AI summary
A passive optical network (PON) device, system and method include an optical line terminal (OLT) receiver configured to receive multiple signals at different wavelengths simultaneously and enable multiple transmitters to operate at the same time during one upstream time slot. The optical line terminal employs Orthogonal Frequency Division Multiple Access (OFDMA) to transparently support a plurality of applications and enable dynamic bandwidth allocation among these applications where the bandwidth is allocated in two dimensional frequency and time space.