Active Ethernet Cable Signaling Conversion
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Solution Overview
Problem
Current Ethernet standards face challenges in supporting high data rates beyond 50 Gbps due to increased channel attenuation and dispersion, making it difficult to manufacture affordable and robust network hardware with a large number of electrical conductors, which become bulky, expensive, and unsuitable for large communication centers.
Innovation Solution
The implementation of active Ethernet cables with transceivers that perform clock and data recovery and re-modulation using differential PAM4 modulation for inbound and outbound data streams, and single-ended NRZ modulation for transit data streams, allowing for robust performance with fewer electrical conductors, enabling data rates up to 800 Gbps and beyond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the number of electrical conductors is doubled to support higher data rates, then the data rate increases, but the cable becomes bulky, inflexible, and expensive
Solution Approach 1:
The patent combines multiple data streams into fewer conductors by using active cable technology with transceivers that perform signal processing. Specifically, multiple PAM4 data streams are consolidated and transmitted over fewer conductors using single-ended NRZ modulation, reducing the physical cable size while maintaining high data rates
Solution Approach 2:
The patent changes the signaling parameters from differential PAM4 modulation to single-ended NRZ modulation for the transit signals. This parameter change allows the same data rate to be achieved with fewer conductors, as the NRZ signaling is more efficient for the cable's internal signal transmission
2Speed
If differential PAM4 modulation is used to convey data streams, then data rate increases, but channel attenuation and dispersion increase making robust performance difficult to achieve
Solution Approach 1:
The patent segments the communication function between the active connectors (which handle PAM4 signaling) and the cable conductors (which handle NRZ signaling). This segmentation allows each part to operate in its optimal mode: PAM4 at the interfaces for high data rate and NRZ in the cable for robust transmission with less susceptibility to attenuation and dispersion
Solution Approach 2:
The active transceivers in the connectors act as intermediaries that convert between differential PAM4 signals and single-ended NRZ signals. This intermediary conversion allows the system to benefit from both signaling methods: PAM4's high data rate capability at the interface and NRZ's robustness during cable transmission
3Speed
If 64 or more electrical conductors are used to support 800 Gbps data rates, then data rate increases, but manufacturing cost and complexity increase
Solution Approach 1:
The patent merges multiple high-speed data streams into fewer physical conductors using active signal processing in the connectors. Instead of requiring 64+ separate conductors for 800 Gbps, the system uses fewer conductors with active transceivers that perform multiplexing and signal conversion, significantly simplifying manufacturing
Data Source
AI summary
Mass-manufactured cables suitable for large communication centers may convert from differential PAM4 interface signaling to parallel single-ended NRZ transit signaling at 53.125 GBd to provide bidirectional data rates up to 800 Gbps and beyond. One illustrative cable embodiment includes: electrical conductors connected between a first connector and a second connector, each adapted to fit into an Ethernet port of a corresponding host device to receive an electrical input signal to the cable conveying an outbound data stream from the host device and to provide an electrical output signal from the cable conveying an inbound data stream to that host device. The electrical input and output signals employ differential PAM4 modulation to convey the inbound and outbound data streams. Each of the first and second connectors includes transceivers to perform clock and data recovery on the electrical input signal to extract and re-modulate the outbound data stream for transit via the electrical conductors as respective pairs of electrical transit signals employing single-ended NRZ modulation.