Bandwidth Compression for Optical Transmission Capacity
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Solution Overview
Problem
The increasing demand for higher data rates in optical communication systems leads to a shortage of bandwidth, resulting in high costs for transmitter and receiver devices, making it economically unfeasible to support higher throughput with existing technologies.
Innovation Solution
A method and apparatus for achieving lossless bandwidth compression by manipulating symbol waveforms, reducing the number of symbol transitions, and converting coded data symbols into transformed sequences using a state machine, allowing for efficient spectrum/bandwidth compression, enabling transmission at higher speeds with lower-cost devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher data rates are supported in optical communication systems, then transmission capacity increases, but the cost of transmitter and receiver devices increases exponentially
Solution Approach 1:
The patent applies parameter changes by modifying the modulation format from traditional NRZ to a new modulation scheme that encodes data in both amplitude and duration parameters. This allows achieving higher data rates (6x or more) using existing 25Gbps optical devices without requiring higher bandwidth components, thereby resolving the contradiction between transmission capacity and device cost
Solution Approach 2:
The patent introduces an additional dimension for data encoding by utilizing symbol duration as a second degree of freedom alongside amplitude. Traditional single-dimensional amplitude modulation is extended to two-dimensional modulation where both amplitude levels and symbol durations carry information, enabling exponential increase in transmission capacity without increasing device bandwidth requirements
2Device complexity
If bandwidth compression is used to increase capacity, then device cost decreases, but data transmission fidelity may be compromised
Solution Approach 1:
The patent implements feedback mechanisms through synchronization protocols and equalization techniques that continuously monitor and adjust the received signal. The receiver uses training sequences and channel estimation to compensate for distortions introduced by bandwidth compression, ensuring high data transmission fidelity while using lower-cost devices
Solution Approach 2:
The patent applies prior cushioning by incorporating forward error correction codes and robust modulation design that anticipate and compensate for potential signal degradation. The modulation scheme is specifically designed to be resilient to bandwidth compression effects, preserving data integrity before errors can occur
Data Source
Figure 1(a)~1(b)
Figure 2(a)
Figure 2(b)
AI summary
This application is intended to provide a method for efficient spectrum/bandwidth compression of the transmitted signals in a communication system. A Miller coding is applied to an input NRZ sequence, and a compressed Miller coding is subsequently applied in order to eliminate the symbols of two half slots in the Miller sequence. The transmitting apparatus may further comprise means for converting the symbols output by the compressed Miller coding into a multilevel signal, such as a modified pulse amplitude modulation signal. A method for detecting and decoding the symbols coded with the aforementioned compressed Miller coding and the modified pulse amplitude modulation is also provided.