MAC-PCS Sync Circuitry for Low-Jitter Data Rate Alignment
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Solution Overview
Problem
High-speed communication systems face challenges with excessive latency jitter and storage overhead due to rate matching and alignment marker insertion in the transmit data path between the media access control (MAC) layer and the physical coding sublayer (PCS), which can lead to synchronization issues and reduced efficiency.
Innovation Solution
A modified interface between the MAC and PCS layers that eliminates the need for PCS rate matching and alignment marker insertion storage by using additional data request and valid signals, allowing for a rate control scheme that does not require idle manipulation or specific clock frequencies, thereby streamlining data flow and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rate matching and alignment marker insertion are implemented in the transmit data path, then data integrity and synchronization are maintained, but latency jitter and storage overhead increase
Solution Approach 1:
The patent extracts and removes the rate matching and alignment marker insertion functions from the traditional transmit data path. By eliminating these functions, the patent achieves lower latency jitter and reduced storage overhead while maintaining data integrity through alternative synchronization mechanisms using the modified interface signals.
Solution Approach 2:
Instead of adding rate matching and alignment markers to ensure synchronization, the patent inverts the approach by using a modified interface where the data request and data valid signals directly coordinate timing between MAC and PCS layers, eliminating the need for additional synchronization overhead.
2Reliability
If rate matching and alignment marker insertion are implemented, then synchronization is maintained, but hardware complexity and power consumption increase
Solution Approach 1:
The patent removes the complex rate matching logic and alignment marker insertion hardware from the system. The modified interface with data request and data valid signals provides a simpler hardware architecture that achieves synchronization through direct signal coordination rather than complex processing logic.
3Reliability
If PCS rate matching and alignment marker insertion storage are used, then data transmission reliability is improved, but bandwidth utilization is reduced
Solution Approach 1:
The patent eliminates the storage requirements for rate matching and alignment marker insertion. By removing these storage elements, the patent increases bandwidth utilization while maintaining transmission reliability through the streamlined interface signaling mechanism that coordinates data flow without requiring buffering.
Data Source
AI summary
A system includes a MAC layer and a PCS in communication with the MAC layer via a transmit data path. The transmit data path includes a data request signal transmitted from the PCS to the MAC layer and a data valid signal transmitted from the MAC layer to the PCS. A SYNC pipeline of the PCS generates a copy of the data valid signal that has a same timing as the data valid signal. When the data valid signal from the MAC layer to the PCS matches the copy of the data valid signal generated by the PCS, the PCS is in synchronization with the MAC layer. When the data valid signal from the MAC layer to the PCS does not match the copy of the data valid signal, the PCS ignores input data from the MAC layer and generates an idle symbol to a link partner.