Interleaved ADC Receiver Equalization for 10 G Multimode Fiber

Solution Overview

Problem

Implementing 10 Gbps optical communication systems over multi-mode fibers is challenging due to high dispersion and variability, requiring complex and costly components like 10 G ADCs, which are difficult to build and maintain, especially with the need for channel-dependent impairments compensation.

Innovation Solution

A receiver with an interleaved ADC coupled to a multi-channel equalizer, featuring a feedforward equalizer and Viterbi decoder adapted using the LMS algorithm, along with a lookahead pipelined architecture and open-loop residue amplifiers, provides compensation for channel-dependent impairments and maintains parallelism to reduce complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If 10 G ADCs are used to achieve high data rate transmission, then the data rate is improved, but the device complexity and manufacturing difficulty increase significantly

Engineering Contradiction:

Improvedata rateVSAvoidreceiver complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The receiver is divided into multiple parallel channels operating at lower speeds (e.g., four 2.5 G channels instead of one 10 G channel). Each channel processes a portion of the data stream independently, reducing the speed requirement and complexity of individual components while maintaining the overall 10 G data rate through parallel processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The problem is solved by transitioning from a single high-speed serial channel to multiple parallel channels, effectively adding a spatial dimension to the data transmission. This parallelization approach distributes the processing load and reduces the complexity of each individual channel while achieving the same aggregate data rate.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Speed

If 10 G ADCs are used to achieve high data rate transmission, then the data rate is improved, but the manufacturing cost increases

Engineering Contradiction:

Improvedata rateVSAvoidmanufacturing cost

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The receiver is divided into multiple parallel channels operating at lower speeds (e.g., four 2.5 G channels instead of one 10 G channel). Each channel processes a portion of the data stream independently, reducing the speed requirement and complexity of individual components while maintaining the overall 10 G data rate through parallel processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs multiple lower-cost, lower-speed ADC channels instead of a single expensive high-speed ADC. By using multiple cheaper components that operate at reduced speeds, the overall system achieves the required 10 G performance while significantly reducing the manufacturing cost and complexity of individual components.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If multi-mode fiber is used for transmission, then the ease of installation is improved, but the signal quality deteriorates due to high dispersion

Engineering Contradiction:

Improveease of installationVSAvoidsignal quality

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The receiver is divided into multiple parallel channels operating at lower speeds (e.g., four 2.5 G channels instead of one 10 G channel). Each channel processes a portion of the data stream independently, reducing the speed requirement and complexity of individual components while maintaining the overall 10 G data rate through parallel processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the operating parameters by using multiple lower-speed channels instead of a single high-speed channel. This parameter change allows the system to tolerate the dispersion characteristics of multi-mode fiber while still achieving the required overall data rate, thereby maintaining signal quality despite the fiber's limitations.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10097273B2High-speed receiver architecture

Publication Date: 2018.10.09 MARVELL ASIA PTE LTD

AI summary

A receiver (e.g., for a 10 G fiber communications link) includes an interleaved ADC coupled to a multi-channel equalizer that can provide different equalization for different ADC channels within the interleaved ADC. That is, the multi-channel equalizer can compensate for channel-dependent impairments. In one approach, the multi-channel equalizer is a feedforward equalizer (FFE) coupled to a Viterbi decorder, for example, a sliding block Viterbi decoder (SBVD); and the FFE and/or the channel estimator for the Viterbi decoder are adapted using the LMS algorithm.