PAM4 Transmission Encoding for Mixed 8b/10b and 128b/132b Streams
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Solution Overview
Problem
Existing data transmission standards using non-return-to-zero (NRZ) and 8b/10b encoding struggle to adapt to pulse amplitude modulation 4 (PAM4) due to low affinity, making it difficult to achieve high-speed transmission.
Innovation Solution
A transmission device and reception device that utilize a combination of 2-level and multi-level pulse amplitude modulation, specifically encoding and decoding methods such as 128b/132b and 8b/10b, to generate and process transmission signals with high affinity to PAM4, enabling efficient data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 8b/10b encoding method is adopted, then low consecutive identical digits (CID), DC balance, and error detection are achieved, but compatibility with PAM4 data transmission standard is poor
Solution Approach 1:
The data stream is divided into control symbols and data symbols, with different encoding rules applied to each segment. Control symbols use specific encoding patterns for synchronization and flow control, while data symbols use optimized encoding for PAM4 compatibility, allowing both reliability and adaptability to be maintained simultaneously
Solution Approach 2:
The encoding scheme transitions from traditional NRZ-based 8b/10b to a PAM4-optimized encoding method that changes the fundamental parameters of the encoding process, including the mapping of data bits to pulse amplitudes and the structure of control symbols, thereby achieving both error detection and PAM4 compatibility
2Ease of manufacture
If NRZ encoding is used, then simple implementation is achieved, but affinity to PAM4 transmission standard is low
Solution Approach 1:
The encoding device is designed to handle both control symbols and data symbols with a unified structure that can adapt to different symbol types, maintaining implementation simplicity while achieving PAM4 compatibility through the multi-functional encoding logic that processes different symbol categories according to their specific requirements
Data Source
AI summary
A transmission device includes an encoding circuit and a modulation circuit. The encoding circuit is configured to encode first and second data stream portions of a transmission data stream in accordance with first and second encoding protocols, respectively, convert each M bit of the encoded second data stream portion into a high-resolution value of N bit, and generate a baseband data stream including the encoded first data stream portion and the converted second data stream portion. The modulation circuit is configured to perform a 2N-level pulse amplitude modulation with respect to each N bit of the encoded first data stream portion in the baseband data stream and each N bit of the converted second data stream portion in the baseband data stream, to generate a transmission signal. M is an integer equal to or greater than 1 and N is an integer greater than M.