Digital Multi-Rate Receiver for PON Using Post-Processing
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Solution Overview
Problem
Current digital multi-rate receivers for passive optical networks (PON) face challenges in efficiently handling and decoding upstream signals at varying bitrates, such as 1.25G, 2.5G, and 10G, due to the complexity of time-multiplexed signals and varying optical power and phase issues.
Innovation Solution
An optical multi-rate receiver is designed to convert time-multiplexed optical signals into digital signals, utilizing a burst-mode avalanche photodiode, transimpedance amplifier, low pass filter, and clock and data recovery circuit to handle high and low bitrate components, with a post-processing unit to decode and separate the bitrates, allowing for efficient reception and decoding of signals without sensitivity penalties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single receiver is designed to handle multiple bitrates (1.25G, 2.5G, 10G), then versatility is improved, but device complexity increases due to the need to handle time-multiplexed signals with varying optical power and phase
Solution Approach 1:
The patent implements a universal receiver architecture that can process multiple bitrates (1.25G, 2.5G, and 10G) using a single photodiode and amplifier chain. The receiver uses a uniform 10G sampling clock to capture all signal components, and a digital post-processing unit handles bitrate-specific decoding, eliminating the need for multiple dedicated receivers and reducing overall system complexity.
Solution Approach 2:
The patent introduces a digital post-processing unit as an intermediary between the analog front-end and the final data output. This unit receives the uniformly sampled 10G signal and performs bitrate-specific processing including clock recovery, equalization, and data extraction for different bitrates, thereby managing the complexity of handling multiple rates through a centralized digital processing stage.
2Measurement precision
If high bitrate signals (10G) are received with optimal sensitivity, then measurement precision is improved, but lower bitrate signals (1.25G, 2.5G) suffer from sensitivity penalties due to time-multiplexing overhead
Solution Approach 1:
The patent changes the sampling parameter by using a uniform 10G sampling clock for all signal components regardless of their actual bitrate. This parameter change allows the analog front-end to capture all signals with optimal bandwidth and sensitivity, while the digital post-processing unit adjusts the effective sampling rate for each bitrate through selective clock recovery and data extraction, thereby eliminating sensitivity penalties for lower bitrates.
3Measurement precision
If separate receivers are used for each bitrate, then measurement precision for each rate is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple bitrate-specific receivers into a single universal receiver that processes all bitrates simultaneously. The analog front-end (photodiode and amplifier) is shared across all bitrates, and a single 10G sampling clock is used for all signal components. The digital post-processing unit then separates and decodes the different bitrates, reducing the total number of receivers and associated components while maintaining detection accuracy through bitrate-optimized digital processing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient decoding of optical signals with minimal sensitivity penalties for high bitrate components and achieves significant sensitivity gains for lower bitrate signals, while maintaining low computational complexity and compatibility with existing 10G receivers.
Implementation Method 1
analog bursts are received from an optical multi-rate signal and converted into an analog electrical signal
Data Source
Figure 1~2
Figure 3
Figure 4a~4b
AI summary
The present invention relates to digital multi-rate receivers. In particular, it relates to digital dual rate receivers for passive optical networks. An optical multi-rate receiver (300) is described. The receiver (300) is configured to receive an optical multi-rate signal (200) comprising a first optical signal component (202) at a high bitrate and a second optical signal component at a low bitrate (201, 203), wherein the first (202) and second (201, 203) optical signal components are time-multiplexed. The receiver (300) comprises a high bitrate optical receiver (310) converting the optical multi-rate signal into a digital signal having the high bitrate and a post-processing unit (320) converting the digital signal corresponding to the second optical signal component into a second digital signal having the low bitrate.