Aperiodic Frame Polarity Bit Encoding for Serial Data
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Solution Overview
Problem
Existing serial communication interfaces face challenges in limiting running disparity while minimizing bandwidth loss, especially at high speeds, as conventional line encoding techniques result in significant bandwidth loss to achieve low running disparity limits.
Innovation Solution
The method involves organizing bits into aperiodic frames, computing point disparity, and inverting bit states when the point disparity has the same sign as the threshold, with a polarity bit inserted to signal inversion, thereby limiting running disparity with a statistically lower bandwidth loss compared to conventional codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional line encoding techniques (8b/10b, Nb/(N+1)b) are used to limit running disparity, then running disparity is effectively controlled, but bandwidth loss increases significantly
Solution Approach 1:
The patent transitions from static, periodic frame structures to dynamic, aperiodic frame structures. Frames are generated adaptively based on the current running disparity state, allowing the system to optimize between disparity control and bandwidth utilization in real-time. The frame generation timing and inversion decisions are made dynamically rather than following a fixed periodic pattern.
Solution Approach 2:
The patent changes the fundamental parameter of frame periodicity from fixed to variable. By adjusting frame generation timing based on running disparity thresholds and using probabilistic inversion decisions, the system optimizes the balance between disparity control and bandwidth efficiency. The inversion probability parameter allows fine-tuning of the trade-off between these two objectives.
2Reliability
If periodic frames with systematic polarity bit insertion are used, then running disparity is limited to ±(N+N/2), but bandwidth loss reaches 1/N
Solution Approach 1:
Instead of systematically inserting polarity bits in every frame (excessive action), the patent uses probabilistic insertion based on running disparity thresholds (partial action). Inversion operations are performed only when necessary to correct excessive disparity, rather than as a routine operation in every frame, thereby reducing unnecessary bandwidth overhead.
Solution Approach 2:
The system dynamically adjusts frame inversion decisions based on current running disparity conditions. The aperiodic nature of frame generation allows the system to respond adaptively to actual disparity needs rather than following a rigid periodic schedule, optimizing the balance between disparity control and bandwidth usage.
Data Source
AI summary
The invention relates to a method for serial data transmission, comprising the steps consisting in computing the running disparity (RD) of a bit stream that is being transmitted; when the running disparity reaches a threshold (T), computing a point disparity on a subsequent frame (S) of the stream; if the point disparity has the same sign as the threshold, inverting the states of the bits of the frame in the transmitted bit stream; and inserting into the transmitted bit stream a polarity bit having a state signalling the inversion.