METHOD, APPARATUS AND SYSTEM FOR DATA TRANSMISSION IN A PON - Patent application

Abstract

A method and apparatus for data transmission are provided, including: an optical line terminal (OLT) receiving a first data stream, the first data stream including a first data frame carrying a first service; the OLT slicing the first data frame to generate a plurality of first slices, the first slices having a first preset length and carrying the first service; and the OLT transmitting a second data stream to an optical network unit (ONU), the second data stream including a plurality of first slices, a time period during which the OLT transmits the second data stream including a plurality of consecutive scheduling periods, at least a portion of the time period of each scheduling period being occupied by at least one first slice, and a time interval between at least two consecutive first slices being used fully or partially to transmit data carrying the second service. The at least one first slice transmitted in each scheduling period occupies a first preset slot. The first preset slot has at least one of a fixed duration and a fixed slot center position.

Description

[Technical field]

[0002] The present invention relates to the field of optical communications, and more particularly to a method and apparatus, and a system for data transmission in a passive optical network (PON). [Background technology]

[0003] Passive Optical Network (PON) technology is a point-to-multipoint fiber access technology. A PON system may include an Optical Line Terminal (OLT), an Optical Distribution Network (ODN), and at least one Optical Network Unit (ONU). The OLT is connected to the ODN, and the ODN is connected to a plurality of ONUs. The ONU further includes a service interface and is connected to user equipment through the service interface.

[0004] Taking gigabit-capable PON (GPON) as an example, GPON encapsulation mode (GEM) frames are used to carry data in GPON. This is the most basic data structure. Data of various services are encapsulated into GEM frames and transmitted on GPON lines. The OLT broadcasts GEM frames to each ONU. The GEM frames include a GEM port identifier. Each ONU identifies the GEM frames belonging to the ONU based on the GEM port identifier, obtains the GEM frames belonging to the ONU through filtering, and discards the GEM frames that do not belong to the ONU. The ONU decapsulates the GEM frames belonging to the ONU to form Ethernet frames, and sends the Ethernet frames to user equipment through the service interface.

[0005] In the PON, in the downstream direction of the OLT, the transmission is generally performed based on packet statistical multiplexing. See FIG. 1. Take an example where an upstream port of the OLT receives Ethernet frames of three service types. During scheduling, the OLT generally uses the Ethernet frame as the granularity to perform scheduling. For example, in FIG. 1, when the transmission queue contains an Ethernet frame with a longer packet length, for example, when the first Ethernet frame in the transmission queue of service 2 is currently the longest Ethernet frame to be transmitted, when the Ethernet frame with the longer packet length starts to be transmitted, the Ethernet frame with the shorter packet length in the transmission queue needs to wait for the completion of the transmission of the Ethernet frame with the longer packet length, and then the OLT can transmit another Ethernet frame with a shorter packet length, resulting in a long delay of the Ethernet frame with the shorter packet length. When the transmission queue does not contain an Ethernet frame with a longer packet length, the delay of the Ethernet frame with a short packet length is small, resulting in a large delay variation of the Ethernet frame with a short packet length. Summary of the Invention [Means for solving the problem]

[0006] In view of this, the present application provides a method and apparatus, and a system for data transmission in a passive optical network PON, to reduce the delay and delay variation of service data transmission in the PON.

[0007] According to a first aspect, a method for data transmission is provided. The method includes: an optical line terminal OLT receives a first data stream, the first data stream includes a first data frame, the first data frame carries a first service; the OLT slices the first data frame to generate a plurality of first slices, the length of each first slice being a first preset length; the OLT transmits a second data stream to an optical network unit ONU, the second data stream includes a plurality of first slices, a time period during which the OLT transmits the second data stream includes a plurality of consecutive scheduling periods, at least a portion of the time period of each scheduling period is occupied by at least one first slice, and a time interval between at least two consecutive first slices is used fully or partially to transmit data carrying the second service. At least one first slice is transmitted in each scheduling period of the period of transmitting the first slice. This helps to reduce delay and delay variation of data transmission of the first service.

[0008] According to the first aspect, in a possible implementation, in each scheduling period, at least one first slice occupies a first preset slot, and the first preset slot satisfies at least one of having a fixed duration and having a fixed slot center position. In each scheduling period, the duration of the first preset slot is fixed. This ensures that the first slice can be transmitted for a fixed duration in each scheduling period. In other words, data carrying the first service can be transmitted for the duration of the first preset slot. This further helps to reduce the delay of data transmission of the first service. Alternatively, in each scheduling period, the slot center position of the first preset slot is fixed in the scheduling period. This ensures that the first slice can be transmitted at a fixed slot center position in each scheduling period. This further helps to reduce the delay variation of data transmission of the first service. Alternatively, in each scheduling period, the duration of the first preset slot is fixed, and the slot center position of the first preset slot in the scheduling period is fixed. This ensures that in each scheduling period, the first slice can be transmitted at a fixed slot position and for a fixed duration, which further helps to reduce the delay of the data transmission of the first service and reduce the delay variation of the data transmission of the first service.

[0009] According to the first aspect or the above possible implementation of the first aspect, in another possible implementation, when a second data frame for carrying a second service is present in the first data stream, the method further includes the OLT generating at least one second slice based on the second data frame. The length of the second slice is a first preset length. The second slice carries the second service. The second data stream further includes the second slice. The OLT transmits at least one second slice in each scheduling period of the period of transmitting the second slice. In one embodiment, the at least one second slice transmitted in each scheduling period occupies a second preset slot, and the second preset slot satisfies at least one of having a fixed duration and having a fixed slot center position. This ensures that in each scheduling period, the data frame of the first service can be transmitted for the duration of the first preset slot, and the data frame of the second service can be transmitted for the duration of the second preset slot. This helps to reduce the delay of data transmission of the first service and the second service, and ensures that the delay and delay variation of data transmission of multiple services can be reduced.

[0010] According to the first aspect or any one of the above possible implementations of the first aspect, in another possible implementation, when a second data frame for carrying a second service is not present in the first data stream, a second slice for carrying the second service is not present in the correspondingly transmitted second data stream, and the method further comprises the OLT generating at least one first idle frame. The length of the first idle frame is a first preset length. The second data stream further comprises the first idle frame. In each scheduling period during which a second slice is not present in the second data stream, the at least one first idle frame occupies a second preset slot. Thus, even if the second service does not currently have traffic, a first idle frame is still inserted in the second data stream to occupy a second preset slot for transmitting the second service. When the second service suddenly has traffic at the next moment, the second service data can still occupy the second pre-configured slot, so that the delay and delay variation of the transmission of the second service can be effectively and stably reduced.

[0011] According to the first aspect or any one of the above possible implementations of the first aspect, in another possible implementation the first data frame is an Ethernet frame or an Optical Data Unit (ODU) frame.

[0012] According to a second aspect, a method for data transmission is provided. The method includes: an ONU receives a second data stream transmitted by an OLT, the second data stream includes a plurality of first slices, a length of the first slice is a first preset length, the first slice carries a first service, a time period during which the ONU receives the second data stream includes a plurality of consecutive scheduling periods, at least a portion of the time period of each scheduling period is occupied by at least one first slice, a time interval between at least two consecutive first slices is fully or partially used to transmit data carrying the second service, the first slice includes a second payload, the ONU identifies each first slice and extracts the second payload in each first slice, and the ONU reassembles the extracted second payload to generate a first data frame. At least one first slice is received in each scheduling period during the period during which the first slice is received. This helps to reduce delay and delay variation of data transmission of the first service.

[0013] According to the second aspect, in a possible implementation, in each scheduling period, at least one first slice occupies a first preset slot, and the first preset slot satisfies at least one of having a fixed duration and having a fixed slot center position. In each scheduling period, the duration of the first preset slot is fixed. This ensures that the first slice can be transmitted for a fixed duration in each scheduling period. In other words, data carrying the first service can be transmitted for the duration of the first preset slot. This further helps to reduce the delay of data transmission of the first service. Alternatively, in each scheduling period, the slot center position of the first preset slot is fixed in the scheduling period. This ensures that the first slice can be transmitted at a fixed slot center position in each scheduling period. This further helps to reduce the delay variation of data transmission of the first service. Alternatively, in each scheduling period, the duration of the first preset slot is fixed, and the slot center position of the first preset slot in the scheduling period is fixed. This ensures that in each scheduling period, the first slice can be transmitted at a fixed slot position and for a fixed duration, which further helps to reduce the delay of the data transmission of the first service and reduce the delay variation of the data transmission of the first service.

[0014] According to the second aspect or the above possible implementation of the second aspect, in another possible implementation, the second data stream further includes a second slice. The length of the second slice is a first preset length. The second slice carries a second service. The time interval is used completely or partially to transmit at least one second slice. The second slice includes a fourth payload. The method further includes the ONU identifying each second slice carrying a second service and extracting a fourth payload in each second slice, and the ONU reassembling the extracted fourth payload to generate a second data frame. This ensures that in each scheduling period, the data frame of the first service can be transmitted for the duration of the first preset slot and the data frame of the second service can be transmitted for the duration of the second preset slot. This helps to reduce the delay of the data transmission of the first service and the second service, and ensures that the delay and delay variation of the data transmission of multiple services can be reduced.

[0015] According to the second aspect or the above possible implementation of the second aspect, in another possible implementation, the second data stream further includes at least one first idle frame. The length of the first idle frame is a first preset length. The time interval is fully or partially used to transmit the at least one first idle frame. The at least one first idle frame in the scheduling period occupies a second preset slot. Thus, even if the second service does not have traffic at present, the first idle frame is still inserted into the second data stream to occupy the second preset slot for transmitting the second service. When the second service suddenly has traffic at the next moment, the second service data can still occupy the second preset slot, so that the delay and delay variation of the transmission of the second service can be effectively and stably reduced.

[0016] According to a third aspect, an apparatus for data transmission is provided. The apparatus includes a first receiving module configured to receive a first data stream, the first data stream including a first data frame, the first data frame carrying a first service; a generating module configured to slice the first data frame to generate a plurality of first slices, the length of the first slice being a first preset length; and a transmitting module configured to transmit a second data stream, the second data stream including a plurality of first slices, a time period during which the apparatus transmits the second data stream includes a plurality of consecutive scheduling periods, at least a portion of the time period of each scheduling period is occupied by at least one first slice, and a time interval between at least two consecutive first slices is used fully or partially to transmit data carrying the second service. At least one first slice is transmitted in each scheduling period of the period of transmitting the first slice. This helps to reduce delay and delay variation of data transmission of the first service.

[0017] According to the third aspect, in a possible implementation, at least one first slice transmitted in each scheduling period occupies a first preset slot, and the first preset slot satisfies at least one of having a fixed duration and having a fixed slot center position. In each scheduling period, the duration of the first preset slot is fixed. This ensures that the first slice can be transmitted for a fixed duration in each scheduling period. In other words, data carrying the first service can be transmitted for the duration of the first preset slot. This further helps to reduce the delay of data transmission of the first service. Alternatively, in each scheduling period, the slot center position of the first preset slot is fixed in the scheduling period. This ensures that the first slice can be transmitted at a fixed slot center position in each scheduling period. This further helps to reduce the delay variation of data transmission of the first service. Alternatively, in each scheduling period, the duration of the first preset slot is fixed, and the slot center position of the first preset slot in the scheduling period is fixed. This ensures that in each scheduling period, the first slice can be transmitted at a fixed slot position and for a fixed duration, which further helps to reduce the delay of the data transmission of the first service and reduce the delay variation of the data transmission of the first service.

[0018] According to the third aspect or the above possible implementation of the third aspect, in another possible implementation, a second data frame for carrying a second service is present in the first data stream. The generating module is further configured to slice the second data frame to generate a plurality of second slices. The length of the second slice is a first preset length. The second data stream further comprises the second slice. The time interval is fully or partially used to transmit at least one second slice. This ensures that in each scheduling period, the data frame of the first service can be transmitted for the duration of the first preset slot and the data frame of the second service can be transmitted for the duration of the second preset slot. This helps to reduce the delay of the data transmission of the first service and the second service, and ensures that the delay and delay variation of the data transmission of the multiple services can be reduced.

[0019] According to a fourth aspect, an apparatus for data transmission is provided. The apparatus includes a second receiving module configured to receive a second data stream transmitted by an optical line terminal OLT, the second data stream including a plurality of first slices, a length of the first slice being a first preset length, the first slice carrying a first service, a time period during which the second receiving module receives the second data stream includes a plurality of consecutive scheduling periods, at least a portion of the time period of each scheduling period being occupied by at least one first slice, a time interval between at least two consecutive first slices being fully or partially used to transmit data carrying a second service, and the first slice including a second payload, an extracting module configured to identify each first slice and extract the second payload in each first slice, and a reassembling module configured to reassemble the extracted second payload to generate a first data frame. At least one first slice is received in each scheduling period during the period during which the first slices are received. This helps to reduce the delay and delay variation of the data transmission of the first service.

[0020] According to the fourth aspect, in a possible embodiment, at least one first slice received by the device in each scheduling period occupies a first preset slot, and the first preset slot satisfies at least one of having a fixed duration and having a fixed slot center position. In each scheduling period, the duration of the first preset slot is fixed. This ensures that the first slice can be transmitted for a fixed duration in each scheduling period. In other words, data carrying the first service can be transmitted for the duration of the first preset slot. This further helps to reduce the delay of data transmission of the first service. Alternatively, in each scheduling period, the slot center position of the first preset slot is fixed in the scheduling period. This ensures that the first slice can be transmitted at a fixed slot center position in each scheduling period. This further helps to reduce the delay variation of data transmission of the first service. Alternatively, in each scheduling period, the duration of the first preset slot is fixed, and the slot center position of the first preset slot in the scheduling period is fixed. This ensures that in each scheduling period, the first slice can be transmitted for a fixed duration at a fixed slot position. This is further helpful in reducing the delay of the data transmission of the first service and reducing the delay variation of the data transmission of the first service.

[0021] According to the fourth aspect or the above possible implementation of the fourth aspect, in another possible implementation, the second data stream further comprises a second slice. The length of the second slice is a first preset length. The second slice carries a second service. The time interval is used completely or partially to transmit at least one second slice. The second slice comprises a fourth payload. The extraction module is further configured to identify each second slice carrying a second service and to extract the fourth payload in each second slice. The reassembly module is further configured to reassemble the extracted fourth payload to generate a second data frame. This ensures that in each scheduling period, the data frame of the first service can be transmitted for the duration of the first preset slot and the data frame of the second service can be transmitted for the duration of the second preset slot. This helps to reduce the delay of the data transmission of the first service and the second service, and ensures that the delay and delay variation of the data transmission of multiple services can be reduced.

[0022] According to a fifth aspect, there is provided a communication system. The communication system according to the fourth aspect Like This includes an apparatus for data transmission.

[0023] According to a sixth aspect, a communication device is provided. The communication device includes a processor and a transceiver. The transceiver is configured to receive a first data stream. The first data stream includes a first data frame. The first data frame carries a first service. The processor is configured to slice the first data frame to generate a plurality of first slices. A length of the first slice is a first pre-set length. The first slice carries the first service. The transceiver is further configured to transmit a second data stream. The second data stream includes a plurality of first slices. A time period during which the transceiver transmits the second data stream includes a plurality of consecutive scheduling periods. At least a portion of the time period of each scheduling period is occupied by at least one first slice. A time interval between at least two consecutive first slices is used completely or partially to transmit data carrying the second service. The communication device also has the beneficial effects described above, and details will not be described again here.

[0024] According to a seventh aspect, a communication device is provided. The communication device includes a processor and a transceiver. The transceiver is configured to receive a second data stream transmitted by an OLT. The second data stream includes a plurality of first slices. The length of the first slice is a first pre-configured length. The first slice carries a first service. A time period during which the transceiver receives the second data stream includes a plurality of consecutive scheduling periods. At least a portion of the time period of each scheduling period is occupied by at least one first slice. A time interval between at least two consecutive first slices is used fully or partially to transmit data carrying the second service. The first slice includes a second payload. The processor is configured to identify each first slice carrying the first service and extract the second payload in each first slice. The processor is further configured to reassemble the extracted second payload to generate a first data frame. The communication device also has the beneficial effects described above, and details will not be described again here.

[0025] According to another aspect of the present application, a computer-readable storage medium is provided. The computer-readable storage medium stores computer software instructions for use by the apparatus for data transmission or communication device according to the third or sixth aspect. When the computer software instructions are executed on a computer, the computer is capable of performing the method according to the aforementioned aspect.

[0026] According to yet another aspect of the present application, there is provided a computer program product, which stores computer software instructions for use by an apparatus for data transmission or a communication device according to the fourth or seventh aspect, which, when executed on a computer, enables the computer to perform a method according to the aforementioned aspect. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a schematic illustration of scheduling an Ethernet frame by an OLT in the current technology; [Diagram 2] FIG. 2 is a schematic diagram of an application scenario according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic diagram of an application scenario according to another embodiment of the present invention. [Figure 4] 2 is a schematic diagram of an Ethernet frame according to one embodiment of the present invention; [Diagram 5] FIG. 2 is a schematic diagram of scheduling according to an embodiment of the present invention, where at least one first slice is transmitted in each scheduling period; [Figure 6] FIG. 2 is a schematic diagram of scheduling according to an embodiment of the present invention, in which the duration of the first pre-configured slot occupied for transmitting the first slice in each scheduling period is fixed; [Figure 7] FIG. 2 is a schematic diagram of scheduling according to an embodiment of the present invention, in which the slot center position of the first pre-configured slot occupied for transmitting the first slice in each scheduling period is fixed; [Figure 8] FIG. 2 is a schematic diagram of scheduling according to an embodiment of the present invention, in which the duration and slot center position of the first pre-configured slot occupied for transmitting the first slice in each scheduling period is fixed; [Figure 9] 2 is a schematic diagram of a method for data transmission according to an embodiment of the present invention; [Figure 10] FIG. 2 is a schematic diagram of scheduling according to an embodiment of the present invention, in which at least one second slice is transmitted in each scheduling period; [Figure 11] FIG. 2 is a schematic diagram of scheduling according to an embodiment of the present invention, in which the duration of the second pre-configured slot occupied for transmitting the second slice in each scheduling period is fixed; [Figure 12]FIG. 2 is a schematic diagram of scheduling according to an embodiment of the present invention, in which the slot center position of the second pre-configured slot occupied for transmitting the second slice in each scheduling period is fixed; [Figure 13] FIG. 1 is a schematic diagram of scheduling according to an embodiment of the present invention, in which the duration and slot center position of the second pre-configured slot occupied for transmitting the second slice in each scheduling period is fixed; [Figure 14] FIG. 2 is a schematic diagram of scheduling according to an embodiment of the present invention; [Figure 15] FIG. 4 is a schematic diagram of scheduling according to another embodiment of the present invention. [Figure 16] 4 is a schematic diagram of a method for data transmission according to another embodiment of the present invention; [Figure 17] 2 is a schematic diagram of an exemplary hardware structure of an apparatus for data transmission according to an embodiment of the present invention; [Figure 18] FIG. 2 is a schematic diagram of an exemplary hardware structure of an apparatus for data transmission according to another embodiment of the present invention; [Figure 19] 2 is a schematic diagram of an exemplary hardware structure of a communication device according to an embodiment of the present invention; [Figure 20] 4 is a schematic diagram of an exemplary hardware structure of a communication device according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The following describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention.

[0029] The technical solutions in the embodiments of the present application are applicable to various passive optical network (PON) systems, such as next-generation PON (NG-PON), NG-PON1, NG-PON2, gigabit-capable PON (GPON), 10 gigabit per second PON (XG-PON), 10-gigabit-capable symmetric passive optical network (XGS-PON), Ethernet PON (Ethernet PON, EPON), 10 gigabit per second EPON (10G-EPON), next-generation EPON (NG-EPON), wavelength-division multiplexing (WDM) PON, time-and-wavelength-division multiplexing (TDM) PON, and so on. PONs include 25 gigabit per second PON (25G-PON), 50 gigabit per second PON (50G-PON), 100 gigabit per second PON (100G-PON), 25 gigabit per second EPON (25G-EPON), 50 gigabit per second EPON (50G-EPON), 100 gigabit per second EPON (10 ...PON), 100 gigabit per second EPON (100G-PON), 100 gigabit per second EPON (100G-PON), 100 gigabit per second EPON (1 It can be applied to GPON, 100G-EPON, 100G-EPON, as well as other rates of GPON and EPON.

[0030] Figure 2 is a schematic diagram of an application scenario according to an embodiment of the present invention. Please refer to Figure 2. It can be known that the PON system includes an OLT 110, an ODN 120, and an ONU 130. The OLT includes at least one upstream port, the upstream port of the OLT is connected to a broadband network gateway (BNG) 140, the upstream port of the BNG is connected to a core router (CR) 150, and the upstream port of the OLT receives an Ethernet frame (also called an Ethernet packet) sent by the CR via the BNG. The upstream port of the OLT may alternatively be directly connected to the CR, and the OLT directly receives the Ethernet frame sent by the CR.

[0031] It can be understood that the Ethernet frames received by the OLT may include Ethernet frames carrying different types of services, e.g., Ethernet Frame 1 carries Service 1, Ethernet Frame 2 carries Service 2, and so on.

[0032] In one embodiment, the Ethernet frame includes a service identifier that identifies a service carried in the Ethernet frame. The OLT identifies the service carried in the Ethernet frame based on the service identifier in the Ethernet frame. It can be understood that the Ethernet frame may be a common Ethernet frame (e.g., an Ethernet frame received from a BNG), the service identifier is a virtual local area network (VLAN) identifier (ID), or the Ethernet frame is an Ethernet frame encapsulated by a tunnel (e.g., an Ethernet frame received directly from a CR), and the service identifier is a service identifier field in the tunnel header.

[0033] In another embodiment, an OLT may identify the service carried in an Ethernet frame by the upstream port that receives the Ethernet frame. For example, upstream port 1 of an OLT is configured to receive Ethernet frame 1 carrying service 1, and upstream port 2 is configured to receive Ethernet frame 2 carrying service 2. By default, Ethernet frames received by upstream port 1 of an OLT carry service 1, and Ethernet frames received by upstream port 2 carry service 2.

[0034] Figure 3 is a schematic diagram of an application scenario according to another embodiment of the present invention. Please refer to Figure 3. It can be known that a PON system includes an OLT, an ODN, and an ONT. The OLT includes at least one upstream port. The upstream port of the OLT is connected to an optical transport network (OTN) device 160 and is configured to receive an optical data unit (ODU) frame transmitted by the OTN device. The ODU frame is also called an optical channel data unit (ODU) frame.

[0035] It can be understood that the ODU frames received by the OLT may include ODU frames carrying different types of services, for example, ODU frame 1 carries service 1, and ODU frame 2 carries service 2.

[0036] In one embodiment, the ODU frame includes a service identifier that identifies a service carried in the ODU frame. The OLT identifies the service carried in the ODU frame according to the service identifier in the ODU frame.

[0037] In another embodiment, the OLT may identify the service carried in the ODU frame by the upstream port that receives the ODU frame. For example, upstream port 1 of the OLT is configured to receive ODU frame 1 carrying service 1, and upstream port 2 is configured to receive ODU frame 2 carrying service 2. By default, the ODU frame received by upstream port 1 of the OLT carries service 1, and the ODU frame received by upstream port 2 carries service 2.

[0038] It can be understood that the application scenarios shown in Figures 2 and 3 are just examples. In practical applications, the apparatus or device connected to the upstream port of the OLT is not limited to the two examples above.

[0039] For ease of explanation, in the following, the data streams received by the upstream port of the OLT are collectively referred to as the first data stream. The first data stream includes a data frame, which may be an Ethernet frame in the scenario of FIG. 2, an ODU frame in the scenario of FIG. 3, or a frame in another scenario. Based on different services carried in the data frame, for example, the data frame may be divided into a first data frame carrying a first service and a second data frame carrying a second service, etc. The Ethernet frame, the ODU frame, or the above other forms of frames may be collectively referred to as the first data frame or the second data frame.

[0040] The following provides a method for data transmission in a PON. Figure 9 is a schematic diagram of a method for data transmission according to an embodiment of the present invention. The method includes:

[0041] Step S200: An OLT receives a first data stream, where the first data stream includes a first data frame, and the first data frame carries a first service.

[0042] Step S201: An OLT slices a first data frame to generate a plurality of first slices, where a length of each first slice is a first preset length, and the first slice carries a first service.

[0043] For example, in GPON, the first slice is a GEM frame; in XGPON, the first slice is an XGEM frame; in other types of PON systems, the first slice is of other corresponding encapsulation types, which may be understood to be not described in detail again here.

[0044] The first data frame includes a first payload and another field. An example is used in which the first data frame is an Ethernet frame, as shown in FIG. 4. FIG. 4 is a schematic diagram of converting an Ethernet frame into a GEM frame according to an embodiment of the present invention. The first payload may include, for example, a Destination address (DA) field, a Source address (SA) field, a Length / Type field, a Media Access Control (MAC) client Data field, and a Frame Check Sequence (FCS) field. Other fields of the first data frame may include, for example, an interpacket gap (IPG) field. A Preamble field, a start-of-frame delimiter (SFD) field, and an end of frame (EOF) field.

[0045] Step S201 includes: when the length of the first payload is longer than a second preset length, the OLT divides the first payload into at least two parts, and a second payload is generated corresponding to each part, and the length of the second payload is equal to the second preset length, and the second preset length is shorter than the first preset length; the OLT adding a frame header to each second payload to form a first slice; and any of the second payloads satisfies either of the following conditions 1 and 2: Condition 1: The second payload includes a portion obtained by splitting the first payload; Condition 2: The second payload includes a portion obtained by splitting the first payload and padding bits.

[0046] For example, the second preset length is 66 bytes and the length of the first payload is 168 bytes. Therefore, the length of the first payload is longer than 66 bytes, and the OLT may divide the first payload into three parts.

[0047] In one embodiment, in the three parts obtained by the split, the first part and the second part are both 66 bytes in length, and the third part is 36 bytes in length. The first part and the second part are the second payload (condition 1 is met). The third part and 30 padding bits form the second payload of 66 bytes (condition 2 is met).

[0048] In another embodiment, in the three parts obtained by the splitting, each part has a length of 56 bytes, and each part and 10 bytes padding bits form a second payload of 66 bytes each (condition 2 is met).

[0049] It can be understood that the above description is just an example, and as long as the second payload satisfies any of the above conditions 1 and 2, the length of each part obtained by splitting the first payload can be selected based on actual requirements.

[0050] In an example where the first slice is a GEM frame, as shown in FIG. 4, the GEM frame includes a frame header and a second payload, and the frame header includes a PLI field, a Port-ID field, a PTI field, and an HEC field. The PLI indicates the length of the second payload. The Port ID uniquely identifies different GEM Ports. The PTI indicates a payload type identifier, mainly identifying the status and type of data currently being transmitted, for example, whether the data is an OAM (Operation, Administration, and Maintenance) message or whether the transmission of the data has been completed. The HEC provides a forward error correction coding function to ensure the transmission quality.

[0051] Step S202: The OLT transmits a second data stream to the optical network unit ONU, the second data stream includes a plurality of first slices, the time period during which the OLT transmits the second data stream includes a plurality of consecutive scheduling periods, at least a portion of the time period of each scheduling period is occupied by at least one first slice, and the time interval between at least two consecutive first slices is occupied by a second service. SThe second data stream is used completely or partially to transmit the data it carries. It can be understood that the time period for transmitting the second data stream may include multiple scheduling periods, and in each scheduling period, at least one first slice is transmitted. As shown in FIG. 5, in five scheduling periods TP1 to TP5, in each scheduling period TP2 to TP4, at least one first slice is transmitted, and in TP1 and TP5, no first slice is transmitted. Therefore, the time period from TP2 to TP4 may be referred to as the time period for transmitting the second data stream. In each scheduling period of the time period for transmitting the second data stream, at least one first slice is transmitted. This helps to reduce the delay and delay variation of the data transmission of the first service.

[0052] In one embodiment, at least one first slice transmitted in each scheduling period occupies a first preset slot, the first preset slot having at least one of a fixed duration and a fixed slot center position.

[0053] In one embodiment, as shown in Figure 6, in each scheduling period, the duration of the first preset slot is fixed. This ensures that the first slice can be transmitted for a fixed duration in each scheduling period. In other words, the data carrying the first service can be transmitted for the duration of the first preset slot. This further helps to reduce the delay of the data transmission of the first service.

[0054] In one embodiment, as shown in Figure 7, in each scheduling period, the slot center position of the first preset slot is fixed in the scheduling period. This ensures that in each scheduling period, the first slice can be transmitted at a fixed slot center position. This further helps to reduce the delay variation of the data transmission of the first service.

[0055] In one embodiment, as shown in Figure 8, in each scheduling period, the duration of the first preset slot is fixed, and the slot center position of the first preset slot in the scheduling period is fixed. This ensures that in each scheduling period, the first slice can be transmitted for a fixed duration at a fixed slot position. This is further helpful in reducing the delay of the data transmission of the first service and reducing the delay variation of the data transmission of the first service.

[0056] Step S203: The ONU receives a second data stream sent by the OLT, where the second data stream includes the first slice.

[0057] Step S204: The ONU identifies each first slice carrying a first service, and extracts a second payload in each first slice.

[0058] Step S205: The ONU reassembles the extracted second payload to generate a first data frame. For example, the ONU may reassemble the second payload to generate a first payload, and then prepend a corresponding frame header to the first payload to generate the first data frame.

[0059] In another embodiment, it can be understood that the first data stream received by the OLT may include data frames of at least two services. For example, in addition to the first data frame carrying the first service, the first data stream may further include a second data frame carrying the second service. As shown in Figure 16, the method further includes:

[0060] Step S206: The OLT slices the second data frame to generate a plurality of second slices, where the length of the second slices is the first preset length, and the second slices carry a second service.

[0061] It can be understood that the details of step S206 are similar to the details of step S201, the second data frame is similar to the first data frame, and the second slice is similar to the first slice, and the details will not be described again here.

[0062] The second data stream further includes a second slice, and the time interval is used completely or partially to transmit at least one second slice. At least one second slice transmitted in each scheduling period occupies a second preset slot, and the second preset slot satisfies at least one of having a fixed duration and having a fixed slot center position. For example, the duration and slot center position of the first preset slot are fixed. Please refer to Fig. 10 to Fig. 13. Fig. 10 is a schematic diagram of a scheduling in which at least one second slice is transmitted in each scheduling period. Fig. 11 is a schematic diagram of a scheduling in which the duration of the second preset slot occupied by the second slice transmitted in each scheduling period is fixed. Fig. 12 is a schematic diagram of a scheduling in which a fixed slot center position occupied by the second slice transmitted in each scheduling period is fixed. Fig. 13 is a schematic diagram of a scheduling in which the duration and slot center position occupied by the second slice transmitted in each scheduling period are fixed. For detailed description, please refer to the relevant description of step S202. The principle and beneficial effects are similar, and the details will not be described again here.

[0063] In the above step S203, the second data stream further includes a second slice.

[0064] Step S207: The ONU identifies each second slice carrying a second service, and extracts the fourth payload in each second slice.

[0065] Step S208: The ONU reassembles the extracted fourth payload to generate a second data frame.

[0066] For details of receiving and processing the second slice at the ONU side, it can be understood that reference can be made to the relevant description of steps S203, S204, and S205. The aforementioned beneficial effects are similarly achieved, and the details are not described again here.

[0067] In this embodiment, the first slice carrying the first service occupies the first preset slot in each scheduling period, and the second slice carrying the second service occupies the second preset slot in each scheduling period. This ensures that in each scheduling period, the data frame of the first service can be transmitted for the duration of the first preset slot, and the data frame of the second service can be transmitted for the duration of the second preset slot. This helps to reduce the delay of data transmission of the first service and the second service, and ensures that the delay and delay variation of data transmission of multiple services can be reduced.

[0068] It can be understood that the first data stream can further include another data frame carrying a third service or more services. The principle and beneficial effects are similar to those described above, and the details will not be described again.

[0069] In another embodiment, the service data may be discontinuous, and there may be no data for a service within a certain time period, for example, in a certain time period, the data stream received by the OLT includes both a first data frame carrying a first service and a first slice carrying a second service.

[0070] However, in another time period, the first data stream received by the OLT includes a first data frame carrying the first service, but does not include a second data frame carrying the second service, in which case the correspondingly transmitted second data stream does not include a second slice for carrying the second service.

[0071] The OLT generates at least one first idle frame, a length of the first idle frame is a first preset length, the second data stream further includes the first idle frame, the time interval is used fully or partially to transmit the at least one first idle frame, and the at least one first idle frame within the scheduling period occupies a second preset slot.

[0072] Therefore, in this embodiment, even if the second service does not have traffic at present, the first idle frame is still inserted into the second data stream to occupy the second preset slot for transmitting the second service. When the second service suddenly has traffic at the next moment, the second service data can still occupy the second preset slot, so that the delay and delay variation of the transmission of the second service can be effectively and stably reduced.

[0073] Figure 14 is a schematic diagram of scheduling according to an embodiment of the present invention. The upstream port of the OLT receives Ethernet frame 1 carrying service 1, Ethernet frame 2 carrying service 2, and Ethernet frame 3 carrying service 3, respectively. The OLT converts Ethernet frame 1 into GEM frame 1, converts Ethernet frame 2 into GEM frame 2, and converts Ethernet frame 3 into GEM frame 3. The GEM frame 1 carrying service 1 occupies slot 1 of a scheduling period, the GEM frame 2 carrying service 2 occupies slot 2 of a scheduling period, and the GEM frame 3 carrying service 3 occupies slot 3 of a scheduling period. Therefore, it can be guaranteed that data transmissions of service 1, service 2, and service 3 have low delay and delay variation. From Figure 14, it can be known that slot 1 is the shortest, slot 2 is intermediate, and slot 3 is the longest. According to the slot length, it can be known that the bandwidth allocated to service 3 by the OLT occupies half of the total bandwidth, the bandwidth occupied by service 3 is four times the bandwidth occupied by service 1, and the bandwidth occupied by service 2 is three times the bandwidth occupied by service 1. Therefore, in order to ensure that low delay and delay variation can be achieved during data transmission of services with different bandwidth requirements, corresponding bandwidths can be allocated to different services based on the bandwidth requirements of the different services.

[0074] Further, in one embodiment, the first data stream may further include a data frame having a low delay requirement. For example, the first data stream further includes a third data frame. The third data frame carries a third service, and the third service has a low transmission delay requirement. The method further includes: step S211: the OLT slices the third data frame to generate at least one third slice. The second data stream further includes a third slice, and the third slice occupies at least a part of the other slots other than the first pre-configured slot. It can be understood that the third slice cannot be transmitted in a scheduling period.

[0075] FIG. 15 is a schematic diagram of scheduling according to another embodiment of the present invention. An upstream port of an OLT receives an Ethernet frame 1 carrying a service 1, an Ethernet frame 2 carrying a service 2, and an Ethernet frame 3 carrying a service 3, respectively. The OLT converts the Ethernet frame 1 into a GEM frame 1, converts the Ethernet frame 2 into a GEM frame 2, and converts the Ethernet frame 3 into a GEM frame 3. Service 1 and service 2 have low delay requirements, and service 3 has high delay requirements. The GEM frame carrying service 3 occupies slot 1 in a scheduling period, and the GEM frame 1 carrying service 1 and the GEM frame 2 carrying service 2 together occupy other slots of the scheduling period other than slot 1. As shown in FIG. 15, in each of the scheduling periods TP1 to TP5, the GEM frame 1 carrying service 1 occupies a fixed duration and a fixed slot center position. In each scheduling period, it is assumed that the slot occupied by GEM frame 1 is slot 1, and in scheduling period TP2, GEM frame 2 carrying service 2 and GEM frame 3 carrying service 3 occupy other slots than slot 1. In scheduling period TP3, the GEM frame carrying service 2 occupies other slots than slot 1. In scheduling period TP4, GEM frame 2 carrying service 2 and GEM frame 3 carrying service 3 occupy other slots than slot 1. Based on the service priority, packet-level scheduling may be performed on the data frames carrying service 2 and service 3. Thus, it may be guaranteed that the data transmission of service 1 has low delay and low delay variation while packet-level scheduling is performed on the data of service 2 and service 3.

[0076] In one embodiment, the first data frame includes a first service identifier, and the first service identifier identifies the first service, or the OLT determines the first service identifier or the first service carried in the first data frame based on an upstream port that receives the first data frame.

[0077] In one embodiment, the first slice includes a first service identifier, or the OLT transmits the first slice over a first downstream PON port associated with the first service.

[0078] In one embodiment, the second data frame includes a second service identifier, and the second service identifier identifies the second service, or the OLT determines the second service identifier or the second service carried in the second data frame based on the upstream port on which it receives the second data frame.

[0079] In one embodiment, the second slice includes a second service identifier, or the OLT transmits the second slice over a first downstream PON port associated with the second service.

[0080] In one embodiment, the third data frame includes a third service identifier, and the third service identifier identifies a third service, or the OLT determines the third service identifier or the third service carried in the third data frame based on an upstream port that receives the third data frame.

[0081] In one embodiment, the third slice includes a third service identifier, or the OLT transmits the third slice over a first downstream PON port associated with the third service.

[0082] It can be understood that for the process in which the OLT converts the data frames in the first data stream into the data frames in the second data stream, please refer to the above-mentioned related description of step S201, and the details will not be described again here. For the specific embodiment of various data frames in the first data stream, please refer to the above-mentioned related description of the first data frame. The details will not be described again here. For the specific embodiment of various data frames in the second data stream, please refer to the above-mentioned related description of the first slice. The details will not be described again here.

[0083] It can be understood that the details of the second preset slot should refer to the first preset slot. The principle of the second preset slot is similar to that of the first preset slot. The details are not described again here.

[0084] The present invention further provides an apparatus 300 for data transmission. As shown in Fig. 17, the apparatus includes a first receiving module 310, a generating module 320, and a sending module 330. The first receiving module 310 is configured to perform step S200. The generating module 320 is configured to perform step S201 and step S206. The sending module 330 is configured to perform step S202.

[0085] For further details regarding when the modules of the apparatus execute the aforementioned steps, please refer to the relevant descriptions of the aforementioned method embodiments and the accompanying drawings, and the details will not be described again here.

[0086] This embodiment of the present application also has various beneficial effects described in the previous method embodiment, and details will not be described again here.

[0087] The present invention further provides an apparatus 400 for data transmission. As shown in Fig. 18, the apparatus includes a second receiving module 410, an extracting module 420, and a reassembling module 430. The second receiving module 410 is configured to perform step S203, the extracting module 420 is configured to perform step S204 and step S207, and the reassembling module 430 is configured to perform step S205 and step S208.

[0088] For further details when the modules of the apparatus perform the aforementioned steps, please refer to the relevant descriptions of the aforementioned method embodiments and the accompanying drawings, and the details will not be described again here.

[0089] This embodiment of the present application also has various beneficial effects described in the previous method embodiment, and details will not be described again here.

[0090] The present invention further provides a communication device 500. As shown in FIG.

[0091] The processor 510 may be a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit ASIC, or at least one integrated circuit, and is configured to execute related programs to implement the technical solutions provided in the embodiments of the present application.

[0092] The memory 520 may be a Read Only Memory (ROM), a static storage device, a dynamic storage device, or a Random Access Memory (RAM). The memory 520 may store an operating system and another application program. When the technical solutions provided in the embodiments of the present application are implemented using software or hardware, the program code for implementing the technical solutions provided in the embodiments of the present application is stored in the memory 520 and executed by the processor 510.

[0093] In one embodiment, the processor 510 may include the memory 520. In another embodiment, the processor 510 and the memory 520 are two independent structures.

[0094] Transceiver 5 3 The transceiver 540 may include an optical transmitter and / or an optical receiver. The optical transmitter may be configured to transmit an optical signal, and the optical receiver may be configured to receive an optical signal. The optical transmitter may be implemented using a light emitting device, such as a gas laser, a solid-state laser, a liquid laser, a semiconductor laser, or a directly modulated laser. The optical receiver may be implemented using a photodetector, such as a photodetector or a photodiode (e.g., an avalanche diode). The transceiver 540 may further include a digital-to-analog converter and an analog-to-digital converter.

[0095] The processor 510 is configured to perform steps S201 and S206.

[0096] The transceiver 530 is configured to perform steps S200 and S202.

[0097] For further details when the communication device 500 performs the aforementioned steps, please refer to the relevant descriptions of the aforementioned method embodiments and the accompanying drawings, and the details will not be described again here.

[0098] This embodiment of the present application also has various beneficial effects described in the previous method embodiment, and details will not be described again here.

[0099] The present invention further provides a communication device 600. As shown in FIG.

[0100] The processor 610 may be a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit ASIC, or at least one integrated circuit, and is configured to execute related programs to implement the technical solutions provided in the embodiments of the present application.

[0101] The memory 620 may be a Read Only Memory (ROM), a static storage device, a dynamic storage device, or a Random Access Memory (RAM). The memory 620 may store an operating system and another application program. When the technical solutions provided in the embodiments of the present application are implemented using software or firmware, program codes for implementing the technical solutions provided in the embodiments of the present application are stored in the memory 620 and executed by the processor 610.

[0102] In one embodiment, the processor 610 may include the memory 620. In another embodiment, the processor 610 and the memory 620 are two independent structures.

[0103] Transceiver 6 3The transceiver 6 may include an optical transmitter and / or an optical receiver. The optical transmitter may be configured to transmit an optical signal, and the optical receiver may be configured to receive an optical signal. The optical transmitter may be implemented using a light emitting device, such as a gas laser, a solid-state laser, a liquid laser, a semiconductor laser, or a directly modulated laser. The optical receiver may be implemented using a photodetector, such as a photodetector or a photodiode (e.g., an avalanche diode). 3 The clock signal generator may further include a digital-to-analog converter and an analog-to-digital converter.

[0104] The processor 610 is configured to perform steps S204, S207, S205, and S208.

[0105] The transceiver 630 is configured to perform step S203.

[0106] For further details when the communication device 600 performs the aforementioned steps, please refer to the relevant descriptions of the aforementioned method embodiments and the accompanying drawings, and the details will not be described again here.

[0107] This embodiment of the present application also has various beneficial effects described in the previous method embodiment, and details will not be described again here.

[0108] The present invention further provides a communication system. The communication system includes the communication device 500 and the communication device 600 described in the above embodiments. For details, please refer to the above embodiments. The details will not be described again here.

[0109] All or part of the above-mentioned embodiments may be implemented using software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of the present invention are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or another programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired (e.g., coaxial cable, optical fiber, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio, or microwave) manner. The computer-readable storage medium may be any available medium accessible by a computer, or may be a data storage device incorporating one or more available media, such as a server or data center. The usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, or a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a Solid State Disk (SSD)).

[0110] In summary, the above description is only an embodiment of the present invention, and is not intended to limit the protection scope of the present invention. Nohara Any modifications, equivalent replacements, or improvements made without departing from the spirit and scope of the present invention shall fall within the protection scope of the present invention. [Explanation of symbols]

[0111] 110 OLT 120 ODN 130 ONU 140 BNG 150CR 160 OTN Devices 300 Data transmission equipment 310 First Receiving Module 320 Generation Module 330 Transmitting Module 400 Data transmission equipment 410 Second receiving module 420 Extraction Module 430 Reassemble Module 500 Communication Devices 510 Processor 520 Memory 530 Transceiver 600 Communication Devices 610 Processor 620 Memory 630 Transceiver

Claims

1. A method for data transmission in a passive optical network PON, the method comprising: receiving, by an optical line terminal (OLT), a first data stream, the first data stream comprising first data frames and second data frames, the first data frames carrying a first service and the second data frames carrying a second service; slicing, by the OLT, the first data frame to generate a plurality of first slices, each of the first slices having a length of a first preset length; slicing, by the OLT, the second data frame to generate a plurality of second slices, a length of each of the second slices being the first preset length; transmitting, by the OLT, a second data stream to an optical network unit ONU, the second data stream comprising the plurality of first slices and the plurality of second slices, a time period during which the OLT transmits the second data stream comprises a plurality of consecutive scheduling periods, at least a portion of the time period of each of the scheduling periods being occupied by at least one of the first slices, and a time interval between at least two consecutive of the first slices being fully or partially used to transmit at least one of the second slices; A method comprising:

2. 2. The method of claim 1, wherein in each of the scheduling periods, the at least one first slice occupies a first preset slot, the first preset slot having at least one of a fixed duration and a fixed slot center position.

3. 3. The method of claim 1 or 2, wherein in each of the scheduling periods, the at least one second slice occupies a second preset slot, the second preset slot having at least one of a fixed duration and a fixed slot center position.

4. The method comprises: generating, by the OLT, at least one first idle frame, the length of the first idle frame being the first preset length; Further comprising:

3. The method of claim 1, wherein the second data stream further comprises the first idle frame, the time interval being used fully or partially to transmit the at least one first idle frame, and the at least one first idle frame within the scheduling period occupying a second pre-configured slot.

5. The first data frame includes a first payload, and the step of slicing, by the OLT, the first data frame to generate a plurality of first slices includes: splitting, by the OLT, the first payload into at least two parts when a length of the first payload is longer than a second preset length, where a second payload is generated corresponding to each of the parts, the length of the second payload being equal to the second preset length, and the second preset length being shorter than the first preset length; adding, by the OLT, a frame header to each of the second payloads to form the first slice; Including, Any of the second payloads satisfies either of the following conditions 1 and 2:

5. The method according to claim 1, wherein: condition 1: the second payload includes a portion obtained by splitting the first payload; and condition 2: the second payload includes a portion obtained by splitting the first payload and padding bits.

6. The method according to any one of claims 1 to 5, wherein the first data frame is an Ethernet frame or an Optical Data Unit (ODU) frame.

7. 7. The method of claim 1, wherein the first data frame includes a first service identifier, the first service identifier identifying the first service, or the OLT determines the first service identifier or the first service carried in the first data frame based on an upstream port receiving the first data frame.

8. 8. The method of claim 7, wherein the first slice includes the first service identifier, or the OLT transmits the first slice through a first downstream PON port associated with the first service.

9. A method for data transmission in a passive optical network PON, the method comprising: receiving, by an optical network unit (ONU), a second data stream transmitted by an optical line terminal (OLT), the second data stream comprising a plurality of first slices and a plurality of second slices, a length of the first slices being a first preset length, the first slices carrying a first service, a length of the second slices being the first preset length, the second slices carrying a second service, a time period during which the ONU receives the second data stream comprises a plurality of consecutive scheduling periods, at least a portion of the time period of each of the scheduling periods being occupied by at least one of the first slices, a time interval between at least two consecutive of the first slices being fully or partially used to carry at least one of the second slices, the first slices comprising a second payload; identifying, by the ONU, each of the first slices and extracting the second payload of each of the first slices; reassembling, by the ONU, the extracted second payload to generate a first data frame; A method comprising:

10. 10. The method of claim 9, wherein in each of the scheduling periods, the at least one first slice occupies a first preset slot, the first preset slot having at least one of a fixed duration and a fixed slot center position.

11. The method according to claim 1, wherein the second slice includes a fourth payload, the method further comprising: identifying, by the ONU, each of the second slices and extracting the fourth payload of each of the second slices; reassembling, by the ONU, the extracted fourth payload to generate a second data frame; 11. The method of claim 9 or 10, further comprising:

12. 12. The method of claim 11, wherein in each of the scheduling periods, the at least one second slice occupies a second preset slot, the second preset slot having at least one of a fixed duration and a fixed slot center position.

13. 11. The method of claim 9 or 10, wherein the second data stream further comprises at least one first idle frame, a length of the first idle frame being the first preset length, the time interval being used fully or partially to transmit the at least one first idle frame, and the at least one first idle frame within the scheduling period occupying a second preset slot.

14. An apparatus for data transmission in a passive optical network PON, said apparatus comprising: a first receiving module configured to receive a first data stream, the first data stream including first and second data frames, the first data frames carrying a first service and the second data frames carrying a second service; a generating module configured to slice the first data frame to generate a plurality of first slices, a length of the first slice being a first preset length, and to slice the second data frame to generate a plurality of second slices, a length of the second slice being the first preset length; a transmission module configured to transmit a second data stream, the second data stream including the plurality of first slices and the plurality of second slices, a time period during which the device transmits the second data stream includes a plurality of consecutive scheduling periods, at least a portion of a time period of each of the scheduling periods being occupied by at least one of the first slices, and a time interval between at least two consecutive the first slices being used fully or partially to transmit at least one of the second slices; An apparatus comprising:

15. 15. The apparatus of claim 14, wherein in each of the scheduling periods, the at least one first slice occupies a first preset slot, the first preset slot having at least one of a fixed duration and a fixed slot center position.

16. The generating module is further configured to generate at least one first idle frame, the length of the first idle frame being the first preset length; 16. The apparatus of claim 14 or 15, wherein the second data stream further includes the first idle frame, the time interval being used fully or partially to transmit the at least one first idle frame, and the at least one first idle frame within the scheduling period occupying a second pre-configured slot.

17. An apparatus for data transmission in a passive optical network PON, said apparatus comprising: a second receiving module configured to receive a second data stream transmitted by an optical line terminal (OLT), the second data stream comprising a plurality of first slices and a plurality of second slices, a length of the first slice being a first preset length, the first slice carrying a first service, a length of the second slice being the first preset length, the second slice carrying a second service, a time period during which the second receiving module receives the second data stream comprises a plurality of consecutive scheduling periods, at least a portion of the time period of each of the scheduling periods being occupied by at least one of the first slices, a time interval between at least two consecutive of the first slices being fully or partially used to transmit at least one of the second slices, the first slices comprising a second payload; an extraction module configured to identify each of the first slices and extract the second payload of each of the first slices; a reassembly module configured to reassemble the extracted second payload to generate a first data frame; An apparatus comprising:

18. The second slice includes a fourth payload, the extraction module is further configured to identify each of the second slices and extract the fourth payload of each of the second slices; 20. The apparatus of claim 17, wherein the reassembling module is further configured to reassemble the extracted fourth payload to generate a second data frame.

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