Method and device for transmitting low speed signals in optical transport system

A method for transmitting low speed signals in an Optical Transport Network (OTN), said method being implemented by a de-multiplexing device, said method comprising:

• obtaining a multiframe indication upon the completion of Optical Channel Transport Unit (OTU) frame synchronization;
• separating Optical Channel Data Unit (ODU) overhead of each channel from an Optical Channel Data Unit k (ODUk) signal according to the multiframe indication;
• separating Optical Channel Payload Unit (OPU) justification overhead of each channel from Optical Channel Payload Unit k (OPUk) justification overhead according to the multiframe indication;
• separating OPU payload of each channel from the time slots of OPUk payload areas according to the multiframe indication and the payload structure identifier (PSI) corresponding to the multiframe indication;
• and
• making a combination of the ODU overhead, OPU justification overhead and OPU payload of each channel to recover an ODU signal, and recover an original low speed signal from the ODU signal.

A device for transmitting low speed signals in an Optical Transport Network (OTN), comprising:

• more than one synchronization physical interface, for transforming each channel of signal into a Constant Bit Rate (CBR) parallel clock signal and CBR parallel data;
• more than one mapping module, for receiving said CBR parallel clock signal and said CBR parallel data sent from said corresponding synchronization physical interface, mapping said parallel clock signal and data into an Optical Channel Payload Unit (OPU) frame, encapsulating the OPU with Optical Channel Data Unit (ODU) overhead, and outputting an ODU parallel clock signal and ODU parallel data;
• a multiplexing module, for receiving said ODU parallel clock signal and ODU parallel data sent from said more than one mapping module, interleaving each channel of OPU payload in corresponding time slots of Optical Channel Payload Unit k (OPUk), frame interleaving each channel of OPU justification overhead in the justification overhead of OPUk of different frames according to a multiframe indication, and fulfilling the interleaved multiplexing of all ODU overhead according to the multiframe indication to obtain an ODUk signal and clock signal;
• a line module, for receiving said ODUk signal and clock signal sent from the multiplexing module, transforming the ODUk signal into an Optical Channel Transport Unit k (OTUk) signal and outputting the OTUk signal;
• a timing generator, for providing a local timing signal for said mapping modules, multiplexing module and line module.

A device for transmitting low speed signals in an Optical Transport Network (OTN), comprising:

• a line module, for receiving an Optical Channel Transport Unit k (OTUk) signal and transforming said OTUk signal into an Optical Channel Data Unit k (ODUk) signal;
• a de-multiplexing module, for receiving said ODUk signal sent from said line module, separating the ODU overhead of each channel from said ODUk signal, separating the Optical Channel Payload Unit (OPU) justification overhead of each channel from the Optical Channel Payload Unit k (OPUk) justification overhead and separating the OPU payload information of each channel from the time slots of OPUks so as to obtain an ODU signal of each channel;
• more than one de-mapping module, for respectively receiving ODU signals of all channels which are sent from the dc-multiplexing module, recovering a Constant Bit Rate (CBR) parallel clock signal and CBR parallel data;
• more than one synchronization physical interface, for respectively receiving said CBR parallel clock signal and CBR parallel data sent from all de-mapping modules and recovering a ultimate client signal CBR;
• a timing generator, for providing a local timing signal said de-mapping module, de-multiplexing module and line module.

A device for transmitting low speed signals in an Optical Transport Network (OTN), comprising;

• more than one synchronization physical interface, for transforming each channel of Constant Bit Rate (CBR) signal into a CBR clock signal and CBR parallel data;
• for receiving a CBR parallel clock signal and CBR parallel data and recovering a CBR signal;
• more than one mapping/de-mapping module, for receiving the CBR clock signal and CBR parallel data sent from the corresponding synchronization physical interface, mapping the CBR parallel clock signal and CBR parallel data into an Optical Channel Payload Unit (OPU) frame, encapsulating the OPU with Optical Channel Data Unit (ODU) overhead, and outputting an ODU parallel clock signal and ODU parallel data;
• and for respectively receiving ODU signals of all channels, recovering a CBR parallel clock signal and CBR parallel data from an OPU payload area and obtaining, and sending the recovered CBR parallel clock signal and CBR parallel data to the synchronization physical interfaces;
• multiplexing/dc-multiplexing module, for receiving said ODU parallel clock signal and ODU parallel data sent from the mapping/de-mapping module, interleaving each channel of OPU payload in corresponding time slots of Optical Channel Payload Unit k (OPUk), frame interleaving each channel of OPU justification overhead in the justification overhead of OPUk of different frames according to a multiframe indication, and fulfilling the interleaved multiplexing of all ODU overhead according to the multiframe indication to obtain an Optical Channel Data Unit k (ODUk) signal and clock signal;
• and for receiving an ODUk signal, separating the ODU overhead of each channel from the received ODUk signal, separating the OPU justification overhead of each channel from the OPUk justification overhead and separating the OPU payload information of each channel from the time slots of OPUks so as to obtain an ODU signal of each channel, and sending the obtained ODU signal to the mapping/de-mapping module;
• a line module, for receiving said ODUk signal and clock signal sent from said multiplexing/de-multiplexing module, transforming said ODUk signal into an OTUk signal and outputting the OTUk signal;
• for receiving an Optical Channel Transport Unit k (OTUk) signal, transforming the received OTUk signal into an ODUk signal, and sending the ODUk signal to said multiplexing/dc-multiplexing module;
• a timing generator, for providing a signal for said mapping/de-mapping modules, multiplexing/de-multiplexing module and line module.