In one exemplary embodiment, a method includes: inserting an indication of a cyclic prefix length into a transmission; and sending the transmission. In another exemplary embodiment, a method includes: receiving a transmission; and processing the received transmission to obtain an indication of a cyclic prefix length.

A method implemented by a first network element (NE) comprises receiving, by a receiver of the first NE, a burst from a second NE, wherein the burst comprises at least one training symbol (TS), storing, by a memory of the first NE, a channel response for a link between the first NE and the second NE, wherein the first NE is communicatively coupled to the second NE, wherein the channel response is based on a current channel response estimated using at least one TS in the burst and a previously stored channel response, and wherein the previously stored channel response is based on a plurality of bursts previously received from the second NE, and compensating, by a processor coupled to the receiver and the memory of the first NE, modulated symbols in the burst using the channel response.

A cross connect apparatus or system with transparent clocking, consistent with embodiments described herein, connects a selected source or ingress port to a selected destination or egress port and clocks data out of the selected egress port using a synthesized clock that is adjusted to match a recovered clock from the selected ingress port. A transparent clocking system may generate the synthesized clock signal with adjustments in response to a parts per million (PPM) rate detected for the associated recovered clock signal provided by the selected ingress port. The cross connect system with transparent clocking may be a 400 G cross connect system with 10 G resolution. The cross connect system with transparent clocking may be used in optical transport network (OTN) applications, for example, to provide an aggregator and/or an add-drop multiplexer (ADM) or to provide a reconfigurable optical add-drop multiplexer (ROADM) upgrade to a higher data rate.

A method for transmitting a client signal in an optical transport network includes: dividing a payload of an optical payload unit signal into m first-granularity tributary slots; dividing one of the m first-granularity tributary slots into n second-granularity tributary slots, where a rate of the first-granularity tributary slot is n times that of the second-granularity tributary slot, m is a positive integer, and n is a positive integer greater than 1; mapping a first client signal onto a payload in which one or more of the n second-granularity tributary slots are located; adding an overhead of the first-granularity tributary slot and an overhead of the second-granularity tributary slot for the optical payload unit signal, to generate an optical data unit signal; and sending the optical data unit signal.

Systems and methods for the relative phase measurement and alignment of 66B encoded signals include receiving a plurality of 66B encoded signals each comprising sync headers which are periodically converted, determining a phase of each of the plurality of 66B encoded signals based on the periodically converted sync headers, and aligning the phase of each of the plurality of 66B encoded signals based on the determining. The periodically converted sync headers can include changing one of a first bit and a second bit of the sync header. A period of the periodically converted sync header can be set at twice a phase difference which is compensated at an egress point of the plurality of 66B encoded signals.

Systems and methods for the relative phase measurement and alignment of 66B encoded signals include receiving a plurality of 66B encoded signals each comprising sync headers which are periodically converted, determining a phase of each of the plurality of 66B encoded signals based on the periodically converted sync headers, and aligning the phase of each of the plurality of 66B encoded signals based on the determining. The periodically converted sync headers can include changing one of a first bit and a second bit of the sync header. A period of the periodically converted sync header can be set at twice a phase difference which is compensated at an egress point of the plurality of 66B encoded signals.

An error correction encoder (10) includes an interleaver circuit (31), encoding circuits (32.sub.1, 32.sub.2) and a deinterleaver circuit (33). The interleaver circuit (31) generates, in a standard speed mode, a single series of yet-to-be-coded bit sequences (IL.sub.1) on the basis of the bits in plural columns that are arranged at an interval of C columns in a single series of transmission frames, and generates, in a two-times speed mode, two series of yet-to-be-coded bit sequences (IL.sub.1, IL.sub.2) on the basis of the bits in plural columns that are arranged at an interval of C/2 columns in each of two series of transmission frames. The encoding circuits (32.sub.1, 32.sub.2) apply error-correction coding to either the single series of yet-to-be-coded bit sequences (IL.sub.1) or the two series of yet-to-be-coded bit sequences (IL.sub.1, IL.sub.2).

This disclosure provides a service data processing method. The method includes: receiving service data; obtaining a processing manner for processing the service data; performing first timeslot-based multiplexing, bit width conversion, and second timeslot-based multiplexing on the service data when a bandwidth of the service data is less than a first threshold, to obtain an intermediate frame; performing single-level timeslot-based multiplexing on the service data when the bandwidth of the service data is not less than the first threshold, to obtain the intermediate frame; mapping the intermediate frame to an optical transport network (OTN) frame; and sending the OTN frame. A first bit width and a first bandwidth based on which the first timeslot-based multiplexing is performed are different from a second bit width and a second bandwidth based on which the second timeslot-based multiplexing and the single-level timeslot-based multiplexing are performed.

A transmission device of a signal transmission system multiplexing and transmitting a plurality of 8B10B-coded information sequences, which includes: conversion units the number of which is identical to the number of the information sequences, to perform 8B10B-decoding of each of the information sequences, receive one of the information sequences after the decoding, scramble the received information sequence, and add a synchronous pattern indicating a head of a frame to the scrambled information sequence; and a multiplexing unit to multiplex the information sequence outputted from each of the conversion units.

A transmission device of a signal transmission system multiplexing and transmitting a plurality of 8B10B-coded information sequences, which includes: conversion units the number of which is identical to the number of the information sequences, to perform 8B10B-decoding of each of the information sequences, receive one of the information sequences after the decoding, scramble the received information sequence, and add a synchronous pattern indicating a head of a frame to the scrambled information sequence; and a multiplexing unit to multiplex the information sequence outputted from each of the conversion units.