Training Signal Wrapper for OTN Parallel Stream Recovery
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Solution Overview
Problem
High-speed OTN serial stream recovery in parallel stream networks above 40/100 Gbps is challenging due to differential delay and incompatibility of existing OTN signals with semi-parallel channels, requiring new techniques beyond conventional virtual concatenation methods.
Innovation Solution
A training-enhanced OTN frame system is introduced, where a training signal wrapper is added to the ITU G.709 OTN frame, striped into parallel streams, and buffered for transmission, allowing for efficient recovery and equalization in multi-channel OTN networks, using a training signal wrapper with framing, tone, and channel identification information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional virtual concatenation (VCAT) protocol is used to transport high-speed OTN signals over parallel channels, then the signals can be transmitted over independent routes with alternate paths, but additional bandwidth is required for redundant overhead and multiple channels must be monitored increasing system complexity
Solution Approach 1:
The invention segments the training signal into separate training signal portions that are inserted into individual parallel channels. Each channel contains a portion of the training signal rather than the complete signal, allowing receivers to reconstruct the full training signal by combining portions from multiple channels. This segmentation reduces the overhead in each individual channel while maintaining the ability to monitor and recover signals across multiple parallel paths.
2Speed
If VCAT mechanism is used for high-speed OTN transmission, then data can be transported over parallel channels, but additional buffers are required to overcome skew (differential delay) between different media
Solution Approach 1:
The invention applies preliminary action by inserting training signal portions at known positions within the data structure before transmission. These training signal portions serve as reference markers that enable the receiver to detect and compensate for skew and differential delay between parallel channels. By having predetermined training signals available at the start of each channel segment, the system can perform synchronization and skew correction without requiring large additional buffers.
3Speed
If polarization multiplexing with 2 bits per symbol modulation is used for 40/100 Gbps transmission, then faster signal speeds are achieved, but OTN signals lack characteristics for efficient transmission and reception over semi-parallel channels experiencing skew
Solution Approach 1:
The invention introduces training signal portions as an intermediary element between the transmitted data and the receiver's demodulation process. These training signal portions are inserted into the data stream at regular intervals within each parallel channel and serve as reference markers that facilitate the recovery of the original serial stream from the parallel channels. The training signals provide known reference points that help the receiver perform equalization, skew compensation, and synchronization operations, making the high-speed PM-QPSK transmission compatible with OTN recovery requirements.
Data Source
AI summary
Systems and methods are provided for multi-channel ITU G.709 optical transport network (OTN) transmission and receiving. The transmission method accepts a canonical ITU G.709 OTN frame including an OTU overhead (OH) section, an ODU section, and a forward error correction (FEC) parity section. A training signal wrapper is added to the ITU G.709 OTN frame, and at least a portion of a training-enhanced (TE) OTN frame is buffered in a tangible memory medium in preparation for striping. The method stripes the training-enhanced OTN frame into n parallel streams to supply n TE_OTN-PFs (Parallel Frames) at an output.