End-of-Burst Delimiter for Upstream Channel Detection
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Solution Overview
Problem
In Ethernet networks using scrambling encoding schemes like 64B/66B, it is difficult for receivers to efficiently detect the end of a transmission due to indistinguishability from noise, leading to potential latency and errors in upstream burst mode networks, especially in scenarios requiring faster detection.
Innovation Solution
Implementing an End-of-Burst Delimiter (EBD) binary pattern that is long enough to be reliably detected amidst scrambled data, allowing the headend receiver to reset and synchronize with the network efficiently, even in the presence of bit errors or overlapping transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If scrambling encoding scheme is used to achieve DC balance, then spectral characteristics become similar to random noise, but end-of-transmission detection becomes difficult
Solution Approach 1:
The patent introduces an unscrambled end-of-burst delimiter (EBD) as an intermediary signal between the scrambled data payload and the noise period. This EBD acts as a mediator that the receiver can detect without scrambling interference, enabling reliable end-of-transmission detection while maintaining the scrambling-induced DC balance during the data transmission portion.
Solution Approach 2:
The transmission structure is segmented into distinct portions: a scrambled data payload followed by an unscrawbled end-of-burst delimiter and then a noise period. This segmentation allows the receiver to identify the boundary between data and noise through the detectable EBD, resolving the detection difficulty caused by the scrambled portion's noise-like characteristics.
2Reliability
If receiver reset occurs after noise period following scrambled data, then transmission end is detected, but latency increases due to indistinguishability from noise
Solution Approach 1:
The end-of-burst delimiter is transmitted preliminarily before the noise period, providing an advance signal that marks the intended end of transmission. This allows the receiver to prepare for the upcoming noise period and reset its synchronization state without having to wait through the entire noise period or use complex post-detection analysis, thereby reducing latency while maintaining reliability.
3Reliability
If guard time between bursts is increased to account for detection uncertainty, then detection reliability improves, but upstream channel utilization decreases
Solution Approach 1:
The patent changes the detectability parameter of the transmission signal by appending an unscrambled EBD that has distinct statistical properties from both the scrambled data and the noise period. This parameter change enables the receiver to detect transmission ends with high reliability using a shorter guard time, thereby improving upstream channel utilization without sacrificing detection reliability.
Data Source
AI summary
A method of signaling and detecting end-of-transmission on a data communications link that uses scrambling comprises, by a transmitting node of the network, appending an end of burst delimiter (EBD) binary sequence to burst data and transmitting the burst data and the EBD over the communication link to a headend of the network. In a 10 G EPON using a 64B/66B transmission code, the EBD is exemplarily a 198 bit pattern.