System and method for scaling total client capacity with a standard-compliant optical transport network (OTN)

In an Optical Transport Network (OTN), a transmitter for generating a rate-adaptive OTUk frame, the transmitter comprising:

• a mapper having at least one client interface to accept client input data, the mapper is operable to map the client input data into a set of (n) allocated slots in a rate-adaptive OTUk frame comprising (m) slots, where (n) and (m) are positive integers, and where (n) is less than or equal to (m), the mapper is operable to determine a channel quality comprising an optical signal-to-noise rate (OSNR) between the transmitter and a receiver and using the channel quality to determine the number of allocated slots in a payload, where a higher channel quality is associated with a greater number of allocated slots, the mapper is also operable to fill the rate-adaptive OTUk frame, comprising (m−n) unallocated slots, using a process selected from the group consisting of filling the rate-adaptive OTUk frame using parity bits computed from client input data and filling at least a portion of the rate-adaptive OTUk frame with dummy bits, the mapper is also operable to supply the rate-adaptive OTUk frame to a physical layer processor, wherein the physical layer processor detects unallocated slots in the rate-adaptive OTUk frame, the mapper is operable to discard some bits in the rate-adaptive OTUk frame, including at least one bit in the unallocated slots, to obtain a transmit bit stream, convert the transmit bit stream into a sequence of modulated symbols using a modulation scheme, and transmit the modulated symbols on an optical channel, wherein converting the transmit bit stream to the sequence of modulation symbols comprises the modulation scheme being responsive to the number of allocated slots, where a higher order modulation scheme permits a greater number slots to be allocated.

In an Optical Transport Network (OTN) system, comprising:

• a transmitter, operable to:
• determine channel statistics comprising an optical signal-to-noise rate for a fiber span connecting a transmitter to a receiver;
• determine a client input data rate sufficient to meet a minimum communication threshold;
• determine a rate-adaptive OTUk frame format sufficient to carry the client input data rate, the format comprising a set of (n) allocated slots in a payload of client input data in a rate-adaptive OTUk frame comprising (m) slots, where (n) and (m) are positive integers, and where (n) is less than or equal to (m);
• fill the rate-adaptive OTUk frame, including (m−n) unallocated slots, using a process selected from the group consisting of filling the rate-adaptive OTUk frame with parity bits computed from client input data and filling at least a portion of the rate-adaptive OTUk frame with and dummy bits
• supply the rate-adaptive OTUk frame to a physical layer processor;
• the physical layer processor detecting unallocated slots in the rate-adaptive OTUk frame;
• discard some bits in the rate-adaptive OTUk frame, including at least one bit in the unallocated slots, to obtain a transmit bit stream;
• convert the transmit bit stream into a sequence of modulated symbols using a modulation scheme;
• and
• transmit the modulated symbols on an optical channel, wherein converting the transmit bit stream to the sequence of modulation symbols comprises the modulation scheme being responsive to the number of allocated slots, where a higher order modulation scheme permits a greater number slots to be allocated.