WO2013177799A1

WO2013177799A1 - Method and transport device for transmitting client signal in optical transport network

Info

Publication number: WO2013177799A1
Application number: PCT/CN2012/076410
Authority: WO
Inventors: 董立民; 吴秋游; 苏伟
Original assignee: 华为技术有限公司
Priority date: 2012-06-01
Filing date: 2012-06-01
Publication date: 2013-12-05
Also published as: CN102893629A

Abstract

A method and transport device for transmitting client signal in optical transport network, said method includes: the payload field of High Order Optical channel Data Unit flex (HO ODUflex) is divided into n slots, wherein n is a natural number, the rate grade of Optical channel Transport Unit flex (OTUflex), which is corresponded to said HO ODUflex, is n times of GS, and said GS is a preset rate value; a client signal is mapped into Low Order Optical channel Data Unit (LO ODU); said LO ODU is multiplexed in HO ODUflex; FEC data is added to said HO ODUflex to generate OTUflex. In the embodiment of the invention, a client signal is mapped into LO ODU, said LO ODU is multiplexed in HO ODUflex, FEC data is added to said HO ODUflex to generate OTUflex, and said OTUflex is divided into n data channels with GS rate for transmission. In the embodiment of the invention, by constructing HO ODUflex, various LO ODUs can be multiplexed in said HO ODUflex, and the corresponding OTUflex is used to transmit data with flexible rate, therefore, the utilization efficiency of fiber bandwidth in optical transport network is improved.

Description

Method and transmission device for transmitting customer signals in optical transport network

The present invention relates to the field of optical communication technologies, and in particular, to a method and a transmission device for transmitting a client signal in an optical transport network. Background technique

OTN (Optical Transport Network) is the core technology of the transport network. OTN has rich OAM (Operation Administration and Maintenance), powerful TCM (Tandem Connection Monitoring) capability and out-of-band. FEC (Forward Error Correction) capability enables flexible scheduling and management of large-capacity services.

Four line rate fixed OTUs ( Optical channel Transport) are defined in the OTN standard system.

Unit, optical channel transmission unit), respectively 0TU1, OTU2, OTU3, and P OTU4, whose line rate levels are 2.5G, 10G, 40G, and 100G, respectively, in bit/s, that is, bits per second. The four OTUs correspond to four ODUs (Optical Channel Data Units) of the same rate class, namely 0DU1, ODU2, ODU3, and P ODU4. When performing signal multiplexing, a certain rate class ODU may be multiplexed to any ODU higher than the ODU to increase the data transmission rate. Taking the ODU1 multiplexed to the ODU2 as an example, the payload area of the ODU2 can be divided into four time slots (TS, Tributary Slot), and each time slot is used to carry one ODU1 data. In addition, the OTN standard system also defines an ODUflex (Flexible Optical Channel Data Unit) to adapt to data services of various rates. The ODUflex is restored by a General Mapping Procedure (GMP). It is used in any of the above ODUs in which the rate is higher than the ODUflex.

With the development of applications such as the Internet and cloud computing, information traffic in the network has grown exponentially, which requires OTN can provide more available bandwidth and requires OTN to evolve to higher transfer rates, such as 400Gb/s (400 Gbit/s) or lTGb/s (1000 Gbit/s). The development of OTN to higher transmission rates requires high-order modulation techniques (eg, high-order QAM, high-order quadrature amplitude modulation) and multi-carrier techniques (eg, Orthogonal Frequency Division Multiplexing (OFDM)). Multi-carrier technology can The number of subcarriers is selected according to the traffic of the transmitted data. However, compared with the low-order modulation technique, the high-order modulation technique requires a higher OSNR (Optical Signal Noise Rate) for the customer signal under the same transmission distance. Moreover, in the existing network application, because the OTU sets a fixed line rate, the OTN cannot flexibly select the OTU with the appropriate line rate to match the available bandwidth of the fiber according to the change of the transmission distance, thus making the optical transmission network The fiber bandwidth utilization is not high. For example: When the optical transmission network line uses a low-order modulation technology PM-QPSK (Polarization Mux- Quadrature Phase Shift Keying) to transmit a customer signal with a rate of 100G, the customer signal can be transmitted at the maximum. 3000 km, however, if the network application only requires the customer signal to be transmitted over a distance of 1000 km, the OTN has the ability to transmit the customer signal using an OTU with a higher line rate, for example, a high-order modulation technique PM-16QAM can be used. (Polarization Mux- Quadrature Amplitude Modulation, polarization multiplexing 16-order quadrature amplitude modulation) to transmit the customer signal, then the line rate of the OTU can be increased to 200G, however, since the existing OTN standard system does not define the line The OTU with a rate of 200G, that is, the line rate of the OTU can only be maintained at 100G, and cannot be increased to 200G to match the available bandwidth of the fiber, thereby causing waste of available bandwidth of the network. Summary of the invention

The embodiments of the present invention provide a method for transmitting a client signal in an optical transport network and a transmitting device, so as to solve the problem that the OTU adopts a fixed rate in the prior art and the bandwidth utilization of the optical fiber is not high.

In one aspect, a method for transmitting a client signal in an optical transport network is provided, the method comprising: dividing a payload area of a high-order flexible optical channel data unit HO ODUflex into n time slots, where n is a natural number, The speed level of the flexible optical channel transmission unit OTUflex corresponding to the HO ODUflex is n times that of the GS, the GS Is a preset rate value; mapping the received client signal to the low-order optical channel data unit LO ODU; determining that the LO ODU occupies the number of slots of the HO ODUflex, where m is less than or equal to n Constructing an optical channel data tributary unit ODTU of the HO ODUflex, and mapping the LO ODU into the ODTU by using a universal mapping procedure GMP protocol; mapping an ODTU carrying the LO ODU to the HO ODUflex a payload area in which the selected m slots are located; generating OTUflex for adding forward error correction FEC data to the HO ODUflex; and splitting the OTUflex into n data channels of rate GS for transmission.

In another aspect, a transmitting apparatus is provided, the transmitting apparatus comprising a dividing unit, a first mapping unit, a determining unit, a building unit, a second mapping unit, a generating unit, and a transmitting unit. The sending unit is configured to divide the payload area of the high-order flexible optical channel data unit HO ODUflex into n time slots, where the n is a natural number, and the line rate level of the OTUflex corresponding to the HO ODUflex is GS n times, the GS is a preset rate value. The first mapping unit is configured to receive a client signal and map the client signal to a low-order optical channel data unit LO ODU. The determining unit is configured to receive, by the first mapping unit, the LO ODU carrying the client signal, and determine the number of slots of the LO ODU occupying the HO ODUflex, where m is a natural number less than or equal to n. The building unit is configured to construct an optical channel data tributary unit ODTU of the HO ODUflex. The second mapping unit is configured to receive, by the first mapping unit, the LO ODU that carries a client signal, map the LO ODU into the ODTU by using a universal mapping procedure GMP protocol, and carry the LO ODU The ODTU is mapped to the payload area in which the selected m time slots in the HO ODUflex are located. The generating unit is configured to generate OTUflex for adding forward error correction FEC data to the HO ODUflex. The sending unit is configured to receive the OTUflex from the generating unit, and split the OTUflex into n data channels with a rate of GS for transmission.

In a further aspect, a transmitting device is provided, the transmitting device comprising at least one processor, the at least one processor configured to perform: dividing a payload area of a high-order flexible optical channel data unit HO ODUflex into n a time slot, where n is a natural number, the rate level of the flexible optical channel transmission unit OTUflex corresponding to the HO ODUflex is n times the GS, the GS is a preset rate value; mapping the received client signal to Determining, in the low-order optical channel data unit LO ODU, the number of slots m of the HO ODUflex occupying the HO ODUflex, where m is a natural number less than or equal to n; constructing the optical channel data tributary unit ODTU of the HO ODUflex And mapping the LO ODU into the ODTU by using a universal mapping procedure GMP protocol; mapping an ODTU carrying the LO ODU to a payload area where the selected m time slots in the HO ODUflex are located; The HO ODUflex adds forward error correction FEC data to generate OTUflex; and splits the OTUflex into n data channels of rate GS for transmission.

The embodiment of the present invention introduces a HO ODUflex with a new line rate class, and various LO ODUs can be multiplexed into the HO ODUflex, and the corresponding OTUflex is used for flexible rate transmission of data, so that the data bandwidth of the fiber bandwidth and the customer signal is The transmission distance is adapted to improve the utilization efficiency of the optical fiber bandwidth in the optical transport network. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings to be used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any inventive labor.

1A is a schematic structural diagram of an OTN system in an embodiment of the present invention;

1B is a frame structure of a HO ODUflex in an embodiment of the present invention;

2 is a flow chart of a first embodiment of a method of transmitting a client signal in an optical transport network;

3A is a schematic diagram of a first embodiment of dividing HO ODUflex into n time slots;

FIG. 3B is a schematic diagram of a frame structure of an ODTU constructed in an embodiment of the present invention; FIG.

3C is a schematic diagram of a second embodiment of dividing HO ODUflex into n time slots; 4 is a flow chart of an embodiment of dividing n data channels for OTUflex;

Figure 5 is a block diagram of a first embodiment of a transmitting apparatus of the present invention;

Figure 6 is a block diagram showing a first embodiment of a dividing unit in the transmitting apparatus of the present invention;

Figure 7 is a block diagram of a second embodiment of the transmitting apparatus of the present invention;

Figure 8 is a block diagram of a third embodiment of the transmitting apparatus of the present invention;

Figure 9 is a block diagram of a fourth embodiment of the transmitting apparatus of the present invention. detailed description

According to the G709 standard released by the ITU-T (International Telecommunication Union-Telecommunication Standardization Sector) in February 2012, four low-order optical channel data units are defined in the existing OTN technology, namely ODU1. In the embodiment of the present invention, the HO ODUflex (High Order Optical Channel Data Unit flex) is introduced on the basis of the existing low-order ODUflex, and the HO is introduced. After ODUflex, the ODU4 can also be multiplexed into the HO ODUflex as a low-order ODU. For the sake of distinction, the five ODUs of the above-mentioned 0DU1, ODU2, ODU3, ODU4, and low-order flexible ODUflex are collectively referred to as LO ODU (Low Order). Optical channel Data Unit, low-order optical channel data unit;).

As shown in FIG. 1B, the HO ODUflex frame structure defined by the embodiment of the present invention is the same as the ODU frame structure defined by G709. The HO ODUflex frame structure includes 4 rows, and each row has 3824 bytes (columns), and the first column to the first column 14 is the overhead area of the HO ODUflex, and the 15th and 16th columns are the overhead areas of the HO ODUflex optical channel payload unit (OPUflex, Optical channel Payload Unit of flex order), which are 4 rows, 2 columns, 8 bytes, and 17th; Columns to column 3824 are the payload areas of the OPUflex, with a total of 4 rows of 3808 columns 4*3808 bytes for carrying client signals.

In the embodiment of the present invention, the optical channel transmission unit corresponding to the HO ODUflex is an OTUflex (Optical Channel Transport Unit flex), wherein the Chinese meaning of flex is flexible, HO The flex in ODUflex supports flexible optical channel bit rate, OTUflex supports flexible line transmission rate, and the speed relationship between OTUflex and HO ODUflex is: OTUflex = ODUflex (HO) *255/239, OTUflex is the newly introduced line Rate rating. The line rate class of OTUflex is an integer multiple of GS, that is, the line rate class of OTUflex is n*GS. The Chinese meaning of GS (Grid Space) is the interval space, and GS is the preset rate value, and the unit is bit/s. , that is, bits per second, GS is the smallest unit of OTUflex's rate increase and decrease. The value of GS can refer to ITU-T Recommendation G694.1 for the definition of Grid Space, for example, the value of GS. It is 12.5G level or 6.25G level; the interval space in G694.1 refers to the interval between the center frequencies of each optical channel, which is 12.5G level or 6.25G level. The n is a natural number, indicating a line rate level of the OTUflex, and the value of the n may be selected according to a need to transmit a client signal, for example, according to at least one of a data flow, a transmission distance, and a modulation format of the client signal. To decide. Preferably, the value of n is 2 to the power of L, and L is a natural number. The values of n mentioned in the specification are the same.

OTUj (j=l, 2, 3, 4) with rate classes between 2.5G and 100G already exists and is deployed in large quantities on OTN. OTUflex can only define rate levels greater than OTU4, thus better compatible with existing OTUs. rate.

Referring to FIG. 1A, it is a schematic diagram of an OTN architecture in an embodiment of the present invention. As shown in Figure 1A, HO ODUflex and OTUflex are added based on the existing OTN architecture. HO ODUflex is suitable for carrying high-speed Ethernet data, such as 400GE or 1TGE Ethernet data, ODU4 is used to carry 100GE Ethernet data, ODU3 is suitable for carrying STM-256 data, ODU2 is suitable for carrying STM-64 data, ODU1 is used. For carrying STM-16 data, the Chinese name of STM (Synchronous Transport Module) is the synchronous transfer module.

The process of transmitting the client signal in the OTN is to map the client signal to the appropriate LO ODUj (j=l, 2, 3, 4, flex), and the mapping protocol can use the GMP (Generic Mapping Procedure) defined in G709. Universal mapping procedure) or GFP (Generic Frame Procedure); one or more LO ODUj (j=l, 2, 3, 4, flex) carrying client signals are multiplexed to the embodiment of the present invention by GMP protocol The defined HO ODUflex; HO ODUflex adds Forward Error Correction (FEC) data to OTUflex; then splits OTUflex into n data lanes of rate GS for transmission.

Specifically, before the multiplexing of the LO ODUj to the HO ODUflex, the payload area of the HO ODUflex is divided into n time slots TS (Tributary Slot, TS), and at this time, the structure of the HO ODUflex It is called HO ODUf.n. Correspondingly, the structure of the optical channel data unit OPUflex of the HO ODUflex is called OPUf.n, and the rate of each time slot (TS, time slot) is TS = GS*238/255.

The columns 17 to 3824 of the HO ODUflex are payload areas, and the payload area of the HO ODUflex includes 3808 columns. The manner in which the HO ODUflex payload area is divided into n time slots is as follows:

As shown in FIG. 3A, a single frame time slot is divided for each frame HO ODUflex. From the 17th column to the 3824th column of each HO ODUflex, that is, from the 1st column to the 3808th column of the payload area of each HO ODUflex, sequentially labeling each column from 1 to n, each frame HO ODUflex The 3808 column of the payload area is labeled ModC3808/n), and ModC3808/n) represents the remainder obtained by dividing 3808 by n. Columns with the same label belong to the same time slot, each time slot occupies an int (3808/n) column, and the int (3808/n) indicates that 3808 is divided by n and rounded down. For example, when n is equal to 5, 3808/5 is equal to 761.6, Mod (3808/5) is equal to 3, and int (3808/5) is equal to 761. When n is not divisible by 3808, the bytes in the columns corresponding to the remainder are filled. For example, when n is equal to 5, 5 can divide 3805 columns, and the remaining 3 columns are filled. Since each time slot occupies an int (3808/n) column and each column contains 4 bytes, each time slot occupies 4*int (3808/n) bytes. When the value of n is equal to any of the powers of L, 7, and 2 (L is a natural number less than or equal to 5), the n can be divisible by 3808, that is, the payload area of the HO ODUflex does not exist. The padded bytes.

As shown in FIG. 3C, the multiframe composed of the n frames HO ODUflex is divided into slots as a whole. Such as As shown in FIG. 3A, the payload area of HO ODUflex per frame has 3808 columns, and the division of 3808 columns into n parts may not be equally divided. The multi-frame HO ODUflex multi-frame is divided into slots as a whole. One of the OPUflex overheads of the frame HO ODUflex is used as the multiframe indication, that is, the MFI (Multiple Frame Indication) byte. The value of the MFI byte is the same as the sequence number of the HO ODUflex in the multiframe. As shown in FIG. 3C, the MFI byte takes values from 0 to n-1. Preferably, the MFI byte is carried in row 4, column 16, of HO ODUflex. Since each multiframe has a total of _n *3808 columns, it can be equally divided into n slots, each slot having 3808 columns. For example, in any one of the multiframes, from the first column of the payload area of the first frame HO ODUflex to the 3808th column of the payload area of the HO ODUflex, the payload area of each HO ODUflex is sequentially Each column in the column is numbered from 1 to n, and columns having the same label belong to the same time slot, and each time slot occupies 3,808 columns. Since each time slot occupies 3808 columns and each column contains 4 bytes, each time slot occupies 3808*4 bytes.

In addition to the above methods of dividing time slots, those skilled in the art may adopt other alternative partitioning methods according to examples of the embodiments of the present invention, and these methods are also within the scope of the present invention.

Further, determining that the LO ODU occupies the number of slots of the HO ODUflex, constructs a flexible optical channel data tributary unit ODTUf.mn, where f is an abbreviation of flex, meaning Chinese is flexible, and m indicates ODTUf.mn occupation The number of slots of HO ODUflex is m, and n indicates that the rate level of OTUflex is n*GS. The frame structure of ODTUf.m.n is shown in Figure 3B. The rate of ODTUf.m.n is defined as: ODTUf.m.n = m*TS = m*GS*238/255. The frame structure of ODTUf.m.n includes 4 rows, m*3808 columns of data, and GMP overhead bytes. Preferably, the GMP overhead byte consists of 3 bytes, which are respectively carried in the 16th column 1-3 of the HO ODUflex; or the GMP overhead byte has 6 bytes, including 3 G7044 (G.HAO) Adjust the protocol overhead bytes, which are carried in lines 1-3 of columns 15 and 16 of HO ODUflex.

The multiplexing process of the client signal is specifically: mapping the client signal to the LO ODU (the LO ODU is one of LO ODUflex, or ODUj (j=l, 2, 3 or 4); the LO ODU that will carry the client signal by The GMP protocol is mapped to the ODTUf.mn; the m*3808 column data of the ODTUf.mn carrying the LO ODU is mapped to the selected m time slots in the HO ODUflex, and the GMP overhead bytes are mapped to the OPUflex overhead of the HO ODUflex; HO ODUflex carrying one or more LO ODUs adds FEC data to generate OTUflex.

A method and apparatus for transmitting a client signal in an optical transport network are described in detail below in conjunction with embodiments of the present invention. See picture

2. Flowchart of a first embodiment of a method of transmitting a client signal in an optical transport network.

Step 201: The payload area of the HO ODUflex is divided into n time slots, where n is a natural number, and the line rate level of the OTUflex corresponding to the HO ODUflex is n times the GS, and the GS is a preset rate value. . The value of n is determined according to at least one of data traffic, transmission distance, and modulation format of the client signal.

Step 202: Map the received client signal to the LO ODU.

In this embodiment, after receiving the client signal, the LO ODU is selected according to the type of the client signal, and the client signal is mapped to one or more LO ODUs of 0DU1, ODU2, ODU3, ODU4, and LO ODUflex. For example, Ethernet data of 400GE or ITGE corresponds to LO ODUflex, and Ethernet data of 400GE or 1TGE is mapped to LO ODU such as LO ODUflex. The mapping protocol may use GMP (Generic Mapping Procedure) defined in G709, or GFP (Generic Frame Procedure).

Step 203: Determine the number of slots of the HO ODUflex occupied by the LO ODU, where m is a natural number less than or equal to n.

Step 204: Construct an optical channel data tributary unit ODTU of the HO ODUflex, and set the LO

The ODU is mapped into the ODTU through a GMP protocol. In this embodiment, when a single frame time slot is allocated for each frame HO ODUflex as shown in FIG. 3A, the ODTU includes a GMP overhead byte, and a 4-line, int (3808/n) column payload area. A total of 4 * int (3808 / n) bytes; when used as shown in Figure 3C will be n frames HO ODUflex When the composed multiframe is divided into slots as a whole, the 0DTU includes a GMP overhead byte, and a 4-row, m*3808 column payload area. For example, when the number of slots occupied by the LO ODU is 2, the rate of the ODTU is ODTUf.mn = 2*TS = 2*GS*238/255.

Step 205: Map the ODTU that carries the LO ODU to the payload area where the selected m time slots in the HO ODUflex are located, and map the GMP overhead bytes to the HO ODUflex overhead. For simplicity, the data in the ODTU carrying the LO ODU is sequentially mapped one byte per byte to each byte in the payload area in which the selected m slots in the HO ODUflex are located.

Referring to FIG. 3C, in order to map the ODTU to m (m=2) slots in the HO ODUflex, the 3808*2 columns in the ODTU are mapped to the slots labeled 1 and 2 in the HO ODUflex, shadow The first time slot and the second time slot indicated are time slots in which the ODTU is mapped. Preferably, the GMP overhead byte in this embodiment may be three bytes, or six bytes (including three GHAO adjustment protocol overhead bytes).

Step 206: Add an ETUflex by adding FEC data to the HO ODUflex.

Step 207: Split the OTUflex into n data channels with a rate of GS for transmission.

As shown in FIG. 4, the OTUflex is split into n data channels of rate GS, and the client signals on the n data channels are transmitted to a modulator, and the modulators are used on the n data channels. The client signal is modulated onto the subcarriers for transmission, and each of the subcarriers carries a client signal on one or more data channels. The number of client signals corresponding to each subcarrier corresponds to the modulation format adopted by each subcarrier. When the modulation format is PM or QPSK, one subcarrier corresponds to the client signal on the two data channels; when the modulation format is PM- In QPSK, one subcarrier corresponds to the client signal on the four data channels; when the modulation format is PM-16QAM, one subcarrier corresponds to the client signal on the eight data channels. In this embodiment, the subcarrier is an OFDM (Orthogonal Frequency Division Multiplexing) subcarrier.

This embodiment introduces HO ODUflex with a new line rate class, and various LO ODUs can be multiplexed into the HO ODUflex, and the corresponding OTUflex is used for flexible rate transmission of data, so that the fiber bandwidth is obtained. It is compatible with the data traffic and transmission distance of the customer signal, thereby improving the utilization efficiency of the optical fiber bandwidth in the optical transmission network.

Referring to Figure 5, a block diagram of a first embodiment of a transmitting device in an optical transport network. The transmitting device 500 includes a dividing unit 502, a first mapping unit 504, a determining unit 506, a building unit 508, a second mapping unit 510, a generating unit 512, and a transmitting unit 514.

The dividing unit 502 is configured to divide the payload area of the high-order flexible optical channel data unit HO ODUflex into n time slots, where the n is a natural number, and the line rate level of the OTUflex corresponding to the HO ODUflex is GS n Times, the GS is a preset rate value. The value of n is determined according to at least one of data traffic, transmission distance, and modulation format of the client signal.

The first mapping unit 504 is configured to receive a client signal and map the client signal into the LO ODU. In this embodiment, the first mapping unit 504 selects an LO ODU according to the type of the client signal, and maps the client signal to one or more of 0DU1, ODU2, ODU3, ODU4, and LO ODUflex. For example, 400GE or 1TGE Ethernet data corresponds to LO ODUflex, and 400GE or 1TGE Ethernet data is mapped to LO ODUflex LO ODU. The mapping protocol can use the GMP protocol defined in G709, or the GFP protocol.

The determining unit 506 is configured to receive, by the first mapping unit 504, the LO ODU that carries the client signal, and determine the number of slots of the HO ODU that occupy the HO ODUflex, where m is a natural number less than or equal to n.

The building unit 508 is configured to construct an optical channel data tributary unit ODTU of the HO ODUflex. In this embodiment, the ODTU includes a GMP overhead byte, and a 4-line, m*3808 column payload area. For example, when the number of slots occupied by the LO ODU is 2, the rate of the ODTU is ODTUf.mn = 2*TS = 2*GS*238/255. a second mapping unit 510, configured to receive, by the first mapping unit 504, the LO ODU carrying a client signal, map the LO ODU into the ODTU by using GMP, and carry the LO The ODTU of the ODU is mapped to the payload area in which the selected m slots in the HO ODUflex are located, and the GMP overhead bytes are mapped into the overhead of the OOUflex of the HO ODUflex. For simplicity, the data in the ODTU carrying the LO ODU is mapped byte by byte to each byte in the payload area in which the selected m slots in the HO ODUflex are located.

The generating unit 512 is configured to generate OTUflex for adding forward error correction FEC data to the HO ODUflex. The sending unit 514 is configured to receive the OTUflex from the generating unit 512, and split the OTUflex into n data channels with a rate of GS for transmission.

As shown in FIG. 4, the sending unit 514 splits the OTUflex into n data channels of rate GS, and transmits a client signal on the n data channel to a modulator, and the n data is modulated by a modulator. The client signals on the channel are modulated onto subcarriers for transmission, and each of the subcarriers carries a client signal on one or more data channels. The number of client signals corresponding to each subcarrier corresponds to the modulation format adopted by each subcarrier. When the modulation format is PM or QPSK, one subcarrier corresponds to the client signal on the two data channels; when the modulation format is PM- In QPSK, one subcarrier corresponds to the client signal on the four data channels; when the modulation format is PM-16QAM, one subcarrier corresponds to the client signal on the eight data channels. In this embodiment, the subcarrier is an OFDM (Orthogonal Frequency Division Multiplexing) subcarrier.

Referring to Figure 6, a block diagram of a first embodiment of the dividing unit 502 of Figure 5 is shown. The dividing unit 502 includes: a time slot dividing subunit 620 and an adding subunit 630.

The time slot division sub-unit 620 is configured to: use the multi-frame HO ODUflex multi-frame as a whole, from the first column of the first frame HO ODUflex payload area to the n-th frame HO ODUflex payload area Columns 3808, sequentially labeling each column in the payload area of each HO ODUflex from 1 to n, the columns with the same label belong to the same time slot, and each time slot occupies 3808 columns.

Adding a sub-unit 630, configured to add a multi-frame indication MFI in the OPUflex overhead of each HO ODUflex byte. The MFI byte is one byte, and its value is the same as the sequence number of each HO ODUflex in the multiframe. As shown in FIG. 3C, the MFI byte takes values from 0 to n-1.

In the second embodiment of the dividing unit 502 in FIG. 5, the dividing unit 502 is configured to sequentially label each column from 1 to n from the first column to the third column of the payload area of each HO ODUflex. Columns with the same label belong to the same time slot, each time slot occupies an int (3808/n) column, and int (3808/n) represents 3808 divided by n and rounded down.

Referring to Figure 7, a block diagram of a second embodiment of a transmitting device in an optical transport network. The transmitting device 700 includes at least one processor 702, the at least one processor 702 configured to perform the following operations: dividing the payload area of the HO ODUflex into n time slots, where n is a natural number, and the HO ODUflex corresponds to The line rate level of the OTUflex is n times the GS, the GS is a preset rate value; the received client signal is mapped into the LO ODU; and the number of slots of the HO ODUflex occupying the HO ODUflex is determined. Where m is a natural number less than or equal to n; constructing an optical channel data tributary unit ODTU of the HO ODUflex, and mapping the LO ODU into the ODTU through a GMP protocol; mapping an ODTU carrying the LO ODU Mapping the GMP overhead bytes into the overhead of the HO ODUflex to the payload area of the selected m slots in the HO ODUflex; adding the FEC data to the HO ODUflex to generate the OTUflex; and splitting the OTUflex n data channels of rate GS are transmitted.

The dividing the payload area of the HO ODUflex into n time slots comprises: acquiring n frames HO ODUflexOPUflex, each of the OPUflex divided into HO ODUflex payload areas having 3808 columns; and the n frames HO ODUflex consisting of multiple frames As a whole, from the first column of the payload area of the HO ODUflex of the first frame to the 3808th column of the payload area of the HO ODUflex of the nth frame, sequentially performing each column in the payload area OPUflex of each frame HO ODUflex From 1 to n cyclic labels, columns with the same label belong to the same time slot, each time slot occupies 3808 columns; add multiframe indication MFI bytes in the OPUflex overhead of each HO ODUflex.

In this embodiment, the value of the n is based on the data flow, the transmission distance, and the modulation grid of the client signal. It is determined by at least one of the formulas that the ODTU includes a GMP overhead byte, and a 4-row, m*3808 column payload area. The at least one processor 702 may be a CP1KCentral Processing Unit, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), or a collection of multiple .

Referring to Figure 8, a block diagram of a third embodiment of a transmitting device in an optical transport network is shown. Transfer device 800 includes a memory

802 and at least one processor 804, the memory 802 being connectable to the at least one processor 804, the memory 802 storing instructions executable by the at least one processor 804. The memory 802 also buffers the received client signals.

The at least one processor 804 is configured to execute the instruction to perform the following operations: dividing a payload area of the H0 ODUflex into n time slots, where n is a natural number, and the line rate level of the OTUflex corresponding to the HO ODUflex Is n times the GS, the GS is a preset rate value; mapping the received client signal to the LO 0DU; determining that the LO 0DU occupies the number of slots of the HO ODUflex, where m is a natural number less than or equal to n; constructing an optical channel data tributary unit ODTU of the HO ODUflex, and mapping the LO 0DU into the ODTU through a GMP protocol; mapping an ODTU carrying the LO ODU to a HO ODUflex Mapping the GMP overhead bytes into the overhead of the HO ODUflex in the payload area in which the m slots are located; adding the FEC data to the HO ODUflex to generate the OTUflex; and splitting the OTUflex into n rates as GS The data channel is transmitted.

The dividing the payload area of the HO ODUflex into n time slots comprises: acquiring an OPUflex of an n-frame HO ODUflex, and each of the OPUflex is divided into 3808 columns of the HO ODUflex payload area; and the n-frame HO ODUflex is formed. The multiframe as a whole, from the first column of the payload area of the HO ODUflex of the first frame to the 3808th column of the payload area of the HO ODUflex of the nth frame, sequentially for each frame within the payload area OPUflex of the HO ODUflex A column carries a cyclical label from 1 to n, columns with the same label belong to the same time slot, each time slot occupies 3808 columns; a multiframe is indicated in the OPUflex overhead of each HO ODUflex to indicate MFI bytes. In this embodiment, the value of the n is determined according to at least one of a data flow, a transmission distance, and a modulation format of the client signal, where the ODTU includes a GMP overhead byte and 4 rows, m*3808 columns. Lotus area. The at least one processor 802 may be one of a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), or multiple Collection.

Referring to Figure 9, a block diagram of a third embodiment of a transmitting device in an optical transport network is shown. The transmitting device 900 includes a dedicated integrated circuit 902, a digital signal processor 904, a DAC (Diginal Analog Conventer) 906, a light modulator 908, and a laser 910.

The ASIC 902 is configured to perform the following operations: divide the payload area of the HO ODUflex into n time slots, where n is a natural number, and the line rate level of the OTUflex corresponding to the HO ODUflex is n times of the GS. The GS is a preset rate value; mapping the received client signal to the LO ODU; determining that the LO ODU occupies the number of slots of the HO ODUflex, where m is a natural number less than or equal to n; Constructing an optical channel data tributary unit ODTU of the HO ODUflex, and mapping the LO ODU into the ODTU by using a GMP protocol; mapping the ODTU carrying the LO ODU to the selected m time slots in the HO ODUflex In the payload area, the GMP overhead byte is mapped into the HO ODUflex overhead; the FOC data is added to the HO ODUflex to generate the OTUflex; and the OTUflex is split into n data channels of the rate GS, and The client signals on the n data channels are passed to digital signal processor 904.

The dividing the payload area of the HO ODUflex into n time slots comprises: acquiring an OPUflex of an n-frame HO ODUflex, and each of the OPUflex is divided into 3808 columns of the HO ODUflex payload area; and the n-frame HO ODUflex is formed. The multiframe as a whole, from the first column of the payload area of the HO ODUflex of the first frame to the 3808th column of the payload area of the HO ODUflex of the nth frame, sequentially for each frame within the payload area OPUflex of the HO ODUflex One column carries the label from 1 to n, and the columns with the same label belong to the same time slot, each time slot occupies 3808 Column; Add a multiframe to indicate the MFI byte in the OPUflex overhead of each HO ODUflex.

In this embodiment, the value of the n is determined according to at least one of a data traffic, a transmission distance, and a modulation format of the client signal, where the ODTU includes a GMP overhead byte, and 4 rows, m*3808 columns. Payload area.

The digital signal processor 904 is configured to receive a client signal on the n data channels from the application specific integrated circuit 902, and process a client signal on the n data channels to generate a digital modulated signal required by the optical domain. . When the line rate change of OTUflex causes the number n of data channels to change, the digital signal processor 904 makes corresponding changes to accommodate this change, thereby enabling the transmission of customer signals with flexible line rates.

The digital to analog converter 906 is configured to receive the digitally modulated signal from a digital signal processor 904 and convert the digitally modulated signal into an analog signal.

The optical modulator 908 is configured to receive the analog signal from a digital to analog converter 906, and modulate the analog signal into I and Q components for transmission.

The laser 910 is a device for generating laser light for delivering the laser light to the light modulator 908. In the embodiment of the present invention, by constructing HO ODUflex, various LO ODUs can be multiplexed into the HO ODUflex, and the corresponding OTUflex is used to transmit data at a flexible rate, so that the bandwidth of the optical fiber is adapted to the data traffic and the transmission distance of the client signal, thereby Improve the utilization efficiency of fiber bandwidth in optical transport networks.

It will be apparent to those skilled in the art that the techniques in the embodiments of the present invention can be implemented by means of software plus a necessary general hardware platform. Based on such understanding, the technical solution in the embodiments of the present invention may be embodied in the form of a software product in essence or in the form of a software product, which may be stored in a storage medium such as a ROM/RAM. , a disk, an optical disk, etc., including instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform the methods described in various embodiments of the present invention or portions of the embodiments.

The various embodiments in this specification are described in a progressive manner, with similar parts between the various embodiments. It is sufficient to refer to each other, and each embodiment focuses on differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment.

The embodiments of the present invention described above are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

Rights request

1. A method for transmitting client signals in an optical transport network, characterized in that the method includes: dividing the payload area of the high-order flexible optical channel data unit HO ODUflex into n time slots, where n is a natural number, The rate level of the flexible optical channel transmission unit OTUflex corresponding to the HO ODUflex is n times that of GS, and the GS is a preset rate value;

Map the received client signal into the low-order optical channel data unit LO ODU; Determine the number of time slots m that the LO ODU occupies in the HO ODUflex, where m is a natural number less than or equal to n; Construct the HO ODUflex Optical channel data branch unit ODTU, and map the LO ODU into the ODTU through the general mapping procedure GMP protocol;

Map the ODTU carrying the LO ODU to the payload area where the m time slots selected in the HO ODUflex are located;

Add forward error correction to the HO ODUflex FEC data generation OTUflex; and

The OTUflex is split into n data channels with a rate of GS for transmission.

2. The method according to claim 1, characterized in that dividing the payload area of the HO ODUflex into n time slots includes:

Taking the multiframe composed of the n frames of HO ODUflex as a whole, from the 1st column of the payload area of the first frame HO ODUflex to the 3808th column of the payload area of the nth frame HO ODUflex, each frame of HO is sequentially Each column in the payload area of ODUflex is cyclically numbered from 1 to n. Columns with the same number belong to the same time slot, and each time slot occupies 3808 columns.

3. The method according to claim 2, characterized in that the ODTU includes general mapping procedure GMP overhead bytes and 4 rows and m 3808 column payload areas.

4. The method according to claim 1, characterized in that dividing the payload area of the HO ODUflex into n time slots includes:

From the 1st column to the 3808th column of the HO ODUflex payload area of each frame, perform each column sequentially. The labels are cycled from 1 to n. Columns with the same label belong to the same time slot. Each time slot occupies an int(3808/n) column. int (3808/n) means that 3808 is divided by n and then rounded down.

5. The method according to claim 4, wherein the ODTU includes a general mapping procedure GMP overhead byte and a 4-row, int (3808/n) column payload area.

6. The method according to any one of claims 1 to 5, characterized in that the value of n is determined according to at least one of the data flow, transmission distance and modulation format of the client signal.

7. The method according to any one of claims 1 to 6, characterized in that mapping the client signal to the LO ODU includes: mapping the client signal to the optical channel data unit ODU1, ODU2, ODU3, ODU4, At least one of LO ODUflex.

8. A transmission device in an optical transmission network, characterized in that the transmission device includes: a dividing unit, used to divide the payload area of the high-order flexible optical channel data unit HO ODUflex into n time slots, where, n is a natural number, the line rate level of the OTUflex corresponding to the HO ODUflex is n times that of GS, and the GS is a preset rate value;

The first mapping unit is used to receive client signals and map the client signals into the low-order optical channel data unit LO ODU;

A determining unit, configured to receive the LO ODU carrying the client signal from the first mapping unit, and determine the number m of time slots occupied by the HO ODUflex by the LO ODU, where m is a natural number less than or equal to n;

The construction unit is used to construct the optical channel data branch unit ODTU of the HO ODUflex; the second mapping unit is used to receive the LO ODU carrying the customer signal from the first mapping unit, and pass the LO ODU through universal mapping The procedure GMP protocol is mapped to the ODTU, and the ODTU carrying the LO ODU is mapped to the payload area where the m time slots selected in the HO ODUflex are located;

A generation unit configured to add forward error correction FEC data to the HO ODUflex to generate OTUflex; as well as

A sending unit, configured to receive the OTUflex from the generating unit, and split the OTUflex into n data channels with a rate of GS for transmission.

9. The transmission device according to claim 8, characterized in that the dividing unit includes: a time slot dividing sub-unit, used to take the multiframe composed of the n frames of HO ODUflex as a whole, starting from the first frame of HO From the 1st column of the payload area of ODUflex to the 3808th column of the payload area of HO ODUflex in the nth frame, each column in the payload area of HO ODUflex in each frame is sequentially numbered cyclically from 1 to n, with the same number. The columns belong to the same time slot, and each time slot occupies 3808 columns;

Added subunit for adding multiframe indication MFI bytes in OPUflex overhead of HO ODUflex per frame. The MFI byte is one byte, and its value is the same as the sequence number of each HO ODUflex frame in the multiframe. As shown in Figure 3C, the value of the MFI byte ranges from 0 to n-1.

10. The transmission device according to claim 9, characterized in that the ODTU includes a general mapping procedure GMP overhead bytes and 4 rows and m 3808-column payload areas.

11. The transmission device according to claim 8, characterized in that the dividing unit is used to sequentially perform from 1 to n on each column from the 1st column to the 3808th column of the payload area of HO ODUflex in each frame. Circular labeling, columns with the same label belong to the same time slot, each time slot occupies an int (3808/n) column, int (3808/n) means 3808 divided by n and then rounded down.

12. The transmission device according to claim 11, characterized in that the ODTU includes a general mapping procedure GMP overhead byte and a 4-row, int (3808/n) column payload area.

13. The transmission device according to any one of claims 8 to 12, characterized in that the value of n is determined according to at least one of the data flow, transmission distance and modulation format of the client signal.

14. The transmission device according to any one of claims 8 to 13, characterized in that the first mapping unit is used to map client signals to ODU1, ODU2, ODU3, ODU4, At least one of LO ODUflex.

15. A transmission device, the device comprising at least one processor, characterized in that the at least one processor is configured to execute:

The payload area of the high-order flexible optical channel data unit HO ODUflex is divided into n time slots, where n is a natural number, and the rate level of the flexible optical channel transmission unit OTUflex corresponding to the HO ODUflex is n times that of GS, as described GS is the preset rate value;

Add forward error correction to the HO ODUflex FEC data generation OTUflex; and

The OTUflex is split into n data channels with a rate of GS for transmission.

16. The transmission equipment according to claim 15, characterized in that dividing the payload area of the HO ODUflex into n time slots includes:

17. The transmission equipment according to claim 16, characterized in that the ODTU includes a general mapping procedure GMP overhead bytes and 4 rows and m 3808-column payload areas.

18. The transmission device according to claim 15, characterized in that dividing the payload area of the HO ODUflex into n time slots includes: From the 1st column to the 3808th column of the payload area of HO ODUflex in each frame, each column is sequentially numbered cyclically from 1 to n. Columns with the same number belong to the same time slot, and each time slot occupies int(3808 /n) column, int (3808/n) means 3808 divided by n and then rounded down.

19. The transmission device according to claim 18, wherein the ODTU includes a general mapping procedure GMP overhead byte and a 4-row, int (3808/n) column payload area.

20. The transmission device according to any one of claims 15 to 19, characterized in that the value of n is determined according to at least one of the data flow, transmission distance and modulation format of the client signal.

21. The transmission device according to any one of claims 15 to 20, characterized in that: mapping the client signal to the LO ODU includes: mapping the client signal to the optical channel data unit ODU1, ODU2, ODU3, ODU4 , at least one of LO ODUflex.