An optical line terminal line card and a method for PON compatibility

Abstract

The embodiment of the present application provides a kind of optical line terminal line card and the method compatible with PON function, optical line terminal optical module, MAC module, switch, switch controller, series resistance and pull-down resistance;Optical module and MAC module are connected to form first connection line, series resistance is arranged on the side close to optical module on first connection line;Pull-down resistance is connected with first connection line by second connection line, switch is arranged on second connection line and is located between first connection line and pull-down resistance;Switch controller is connected with optical module and switch respectively;The working mode of current optical module port is detected by switch controller, and series resistance is connected or disconnected according to the working mode to control switch to be on or off, in some implementation process, different PON technology can be realized on a piece of OLT line card, greatly simplify hardware development design, reduce equipment investment cost, flexible guarantee actual use demand.

Description

Technical Field

[0001] The embodiments of the present invention relate to, but are not limited to, the field of optical access communication technology. Specifically, they relate to, but are not limited to, an optical line terminal card and a method compatible with PON functionality. Background Technology

[0002] In fixed broadband network access technologies, Passive Optical Network (PON) has become the primary FTTx solution for major operators worldwide. Currently, the most widely deployed PON technologies are GPON (Gigabit-capable Passive Optical Network), with a downlink rate of 2.5Gb / s and an uplink rate of 1.25Gb / s, and EPON (Ethernet Passive Optical Network), deployed in China, Japan, and South Korea, with a symmetrical uplink / downlink rate of 1.25Gb / s. With the in-depth implementation of strategies such as "Broadband China" and "Speed ​​Up and Price Reduction," my country's fixed broadband network capabilities have significantly improved in recent years. Simultaneously, with the rapid development of services such as 4K / 8K video, VR / AR, and smart homes, operators are facing new demands for bandwidth and full-service operation management, leading to the development of higher-speed PON technologies. For example, 10Gb / s PON has gradually begun commercial deployment, and the selection of 10G PON technology has become a key focus for various operators when upgrading networks and developing new services.

[0003] While OLT (Optical Line Terminal) network elements in related technologies have multiple boards and PON ports, each board's PON port supports only a single configuration mode. Modern networks are complex, and different types of customers have different application needs, requiring the connection of different types of ONU (Optical Network Unit) terminals. However, if a PON port does not support that type, the ONU terminal cannot connect, necessitating hardware replacement. However, replacing hardware boards for cutovers causes application interruptions, and the upgrade process is prone to failures, impacting the user experience. Summary of the Invention

[0004] The optical line terminal and PON-compatible method provided in this invention mainly solve the technical problem that the configuration mode of the PON port on the same OLT line card supporting ONU terminal access is limited in related technologies.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide an optical line terminal block, comprising: an optical module, a MAC module, a switching switch, a switch controller, a series resistor, and a pull-down resistor;

[0006] The optical module and the MAC module are connected to form a first connection line, and the series resistor is provided on the first connection line near the optical module. The pull-down resistor is connected to the first connection line through a second connection line. The switching switch is provided on the second connection line and located between the first connection line and the pull-down resistor. The switch controller is connected to the optical module and the switching switch respectively.

[0007] This invention also provides a method for PON compatibility, comprising:

[0008] The switch controller detects the current operating mode of the optical module port;

[0009] The switch controller controls the switching switch to be turned on or off according to the operating mode;

[0010] When the switching switch is turned on, the optical module output signal is attenuated by the series resistor and biased by the pull-down resistor before being sent to the MAC module.

[0011] When the switch is turned off, the optical module output signal is attenuated by the series resistor and then sent to the MAC module.

[0012] The beneficial effects of this invention are:

[0013] According to embodiments of the present invention, an optical line terminal (OLT) card and a method compatible with PON functionality are provided. The OLT includes an optical module, a MAC module, a switching switch, a switch controller, a series resistor, and a pull-down resistor. The optical module and the MAC module are connected to form a first connection line, and a series resistor is provided on the first connection line near the optical module. The pull-down resistor is connected to the first connection line via a second connection line. The switching switch is located on the second connection line, between the first connection line and the pull-down resistor. The switch controller is connected to both the optical module and the switching switch. The switch controller detects the current operating mode of the optical module port and controls the switching switch to turn on or off, and the series resistor to connect or disconnect, based on the operating mode. In some implementations, this allows for the compatibility of different PON technologies on a single OLT card, greatly simplifying hardware development and design, reducing equipment investment costs, and flexibly ensuring actual usage needs.

[0014] Other features and corresponding beneficial effects of the present invention will be described in the latter part of the specification, and it should be understood that at least some of the beneficial effects will become obvious from the description in the specification. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the hardware matching circuit for the GPON mode in the prior art;

[0016] Figure 2 This is a schematic diagram of the hardware matching circuit for the 10G PON mode in the prior art;

[0017] Figure 3 This is a schematic diagram of a hardware matching circuit compatible with PON function according to Embodiment 1 of the present invention;

[0018] Figure 4 This is a basic flowchart of the method for PON compatibility according to Embodiment 2 of the present invention;

[0019] Figure 5 This is a flowchart illustrating the method for PON compatibility according to Embodiment 2 of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0021] Example 1:

[0022] To address the issue that the configuration mode of the PON port on the same OLT line card supporting ONU terminal access is limited and cannot meet the needs of practical applications, this invention provides an optical line terminal line card that supports both high-speed XGSPON technology and traditional mature low-speed GPON and XGPON technologies.

[0023] Optical Line Terminal (OLT) cards are used in PON systems, which consist of three parts: OLT, ODN (Optical Distribution Network), and ONUs. Therefore, in PON technology applications, the OLT is a crucial central office device, primarily responsible for: connecting to the front-end switch via network cable, converting signals into optical signals, and interconnecting with the user-end splitter via a single optical fiber; and controlling, managing, and ranging user-end ONUs. It should be understood that the OLT is an integrated optoelectronic device, capable of photoelectric conversion, a function mainly implemented by the OLT's optical modules.

[0024] An OLT consists of many boards, each with a PON port for connecting optical fibers. However, optical fiber interfaces generally cannot be directly connected to PON ports, so an optical module needs to be inserted into the PON port before connecting the optical fiber. In this case, the corresponding optical module type can be selected based on the optical fiber interface type.

[0025] In PON technology, PON modes include, but are not limited to, GPON, 10G PON, and XGSPON (symmetrical 10G megabit passive optical network), each corresponding to a type of optical module. Because each OLT board supports only a single configuration mode, it can only connect to a single ONU terminal.

[0026] The following section uses GPON optical modules and 10G PON optical modules as examples to illustrate their hardware matching circuits.

[0027] As shown in Tables 1 and 2, Table 1 shows the level type of the GPON optical module, and Table 2 shows the specifications of the GPON optical module.

[0028] Table 1

[0029]

[0030] Table 2

[0031]

[0032] The GPON optical module outputs a 1.25Gb / s RD signal. The RD signal level is LVPECL (Low Voltage Positive Emitter-Couple Logic), with an LVPECL level of 1600mV. Since the GPON optical module outputs an LVPECL level, while the MAC module's receiving side uses CML (Current Mode Logic), the OLT board needs to adopt... Figure 1 The matching circuit shown is as follows. The 0.1μF capacitor is an AC coupling capacitor; series resistors R1 and R2 are used to attenuate the output to meet the input voltage requirements that the CML receiver can tolerate; pull-down resistors R3 and R4 are used to provide bias current at the LVPECL level.

[0033] As shown in Tables 3 and 4, Table 3 shows the level type of the 10G PON optical module, and Table 4 shows the specifications of the 10G PON optical module.

[0034] Table 3

[0035]

[0036] Table 4

[0037] Parameter Min Max Unit Notes Data Input Differential Swing 120 820 mV CML input, AC coupled Data Output Differential Swing 340 850 mV CML output, AC coupled

[0038] When a 10G PON optical module is inserted into the board, the 10G PON optical module outputs a 10Gb / s RD signal. The RD signal level is CML, and the MAC module receiving side also uses the CML level. Therefore, the OLT board needs to adopt... Figure 2 The matching circuit shown is as follows. The 0.1μF capacitor is an AC coupling capacitor; series resistors R1 and R2 are used to attenuate the output to meet the input voltage requirements tolerated by the CML receiver; there are no pull-down resistors.

[0039] It is evident that there are certain differences in the matching circuits of different types of optical modules, and the main difference lies in whether or not there is a pull-down resistor.

[0040] To achieve compatible use of the PON function on the OLT line card, this embodiment of the invention provides an optical line terminal (OPT) line card. The OPT line card includes an optical module, a MAC module, a switch, a switch controller, a series resistor, and a pull-down resistor. For details, please refer to [link to details]. Figure 3 As shown, this embodiment of the invention takes the implementation of GPON and 10G PON compatibility on a single OLT line card as an example for specific illustration.

[0041] In this embodiment of the invention, the optical module and the MAC module are connected to form a first connection line, and a series resistor is provided on the optical module side of the first connection line; the pull-down resistor is connected to the first connection line through a second connection line, and the switching switch is provided on the second connection line and located between the first connection line and the pull-down resistor; the switch controller is connected to the optical module and the switching switch respectively.

[0042] In this embodiment of the invention, the optical line terminal block further includes a coupling capacitor, which is disposed on the first connection line on the MAC module side. It should be understood that the function of the coupling capacitor is to transmit AC signals from the previous stage to the next stage, while simultaneously blocking DC signals to prevent interference between the operating points of the preceding and following stages. In this embodiment of the invention, a 0.1μF capacitor is used as the coupling capacitor.

[0043] To enable the optical line terminal block (OLP) card to support different types of PON functions simultaneously, the MAC module can use an FPP chip.

[0044] In this embodiment of the invention, the optical module includes an optical interface, which is a compatible interface. In some application scenarios, the compatible interface can be an SFP+ interface, so that both GPON optical modules and 10G PON optical modules can be plugged into the optical interface, achieving compatibility between the two types of optical modules on the single-board circuit matching circuit.

[0045] It should be understood that an optical module is a high-performance optical module used in a PON system, whose main function is to achieve photoelectric conversion. In practical applications, the optical module interfaces with an ONU device. When the optical module is connected to the ONU device, the ONU device can access the electrically erasable programmable read-only memory (EEPROM) of the optical module via the I2C bus to obtain the information stored in the EEPROM. In practical applications, each optical module provides one EEPROM, which stores the transmission parameter information of the optical module, such as center wavelength, transmission rate, and transmission distance.

[0046] In this embodiment of the invention, the optical module and the MAC module are connected to form a first connection line. The first connection line includes a first physical line and a second physical line, which are differential lines. The differential line uses two parallel, equal-length traces to transmit the same signal with a phase difference of 180°. That is, the first and second physical lines are of equal length and parallel to each other; one line transmits a positive signal, and the other transmits a negative signal. The function of the differential line is to resist interference.

[0047] In this embodiment of the invention, the optical module and the MAC module are connected via a differential line. Series resistors are respectively installed on the two physical lines of the differential line, located on the optical module side, to attenuate the signal to meet the reception requirements of the MAC module. Specifically, the series resistors are R1 and R2. Correspondingly, coupling capacitors are respectively installed on the two physical lines of the differential line on the MAC module side.

[0048] In this embodiment of the invention, a second connection line is led out from the first connection line between the series resistor and the coupling capacitor. A pull-down resistor is connected through the second connection line, and a switching switch is provided on the second connection line between the pull-down resistor and the first connection line. Specifically, the first connection line is a differential line, with one line leading out from each of the two differential lines. Each line is connected to a pull-down resistor, R3 and R4. The switching switch is located between the differential line and the pull-down resistor, supporting differential input. In this embodiment of the invention, the pull-down resistor is a DC bias resistor.

[0049] In this embodiment of the invention, the switch controller is connected to the optical module. Specifically, the switch controller and the optical module can be connected via an I2C bus. The I2C bus requires only two wires in hardware: one data line and one clock line. The bus interface is integrated inside the chip, eliminating the need for special interface circuitry. Therefore, the I2C bus simplifies hardware wiring, reduces system costs, and improves system reliability. Furthermore, the bus has extremely low current consumption, is resistant to high noise interference, is compatible with devices of different voltage levels, and has a wide operating temperature range.

[0050] It should be noted that the switch controller can read the Serial ID of the optical module through the I2C bus, thereby determining the type of the current optical module; the switch controller controls the switching switch to be turned on or off according to the type of the optical module.

[0051] In this embodiment of the invention, the switch controller is a programmable logic device (PLD); the switching switch is an analog switch, which is controlled by voltage and has the advantages of fast switching speed, low power consumption, and can support differential input.

[0052] In this embodiment of the invention, the operating modes of the optical module port include GPON mode and 10G PON mode. When the switch controller determines that the operating mode is GPON mode, the output of the optical module is equivalent to an LVPECL driver, and the MAC module is equivalent to a CML receiver. The circuit matching should meet the requirements of AC coupling from LVPECL to CML. The switch controller controls the switching switch to be turned on and connects a pull-down resistor to provide DC bias for LVPECL coupling. When the switch controller determines that the operating mode is 10G PON mode, the output of the optical module is equivalent to a CML driver, and the MAC module is equivalent to a CML receiver. The circuit matching should meet the requirements of AC coupling from CML to CML. At this time, the switch controller should control the output of the switching switch to a high-impedance state, that is, the switching switch should be turned off, to prevent packet loss due to the influence of the pull-down resistor on signal quality.

[0053] It should be noted that the series resistors are set to meet the LVPECL input voltage requirements that the CML receiver can tolerate; at the same time, in order to ensure that the series resistors have little impact on the CML input voltage amplitude and can meet the normal transmission in GPON mode, the resistance value of each series resistor is generally no greater than 24.9Ω.

[0054] Specifically, the optical module output is the RD output, the switch controller is the PLD, and the MAC module is the FPP.

[0055] It should be noted that the working modes of the optical module port in this embodiment of the invention include, but are not limited to, GPON mode and 10G PON mode. A switching switch and a corresponding pull-down resistor can be set according to actual needs to realize an optical line terminal card that is compatible with multiple working modes.

[0056] The optical line terminal card provided in this embodiment of the invention has an optical module and a MAC module connected to form a first connection line. A series resistor is provided on the first connection line near the optical module. A pull-down resistor is connected to the first connection line through a second connection line. A switching switch is set on the second connection line and located between the first connection line and the pull-down resistor. A switch controller is connected to both the optical module and the switching switch. The switch controller detects the current working mode of the optical module port and controls the switching switch to turn on or off according to the working mode to determine whether the series resistor is connected or disconnected. In some implementations, different PON technologies can be compatiblely implemented on a single OLT card, greatly simplifying hardware development and design, reducing equipment investment costs, flexibly ensuring actual usage needs, and effectively reducing the system upgrade and maintenance costs for operators, achieving the goal of smooth upgrades.

[0057] Example 2:

[0058] This invention proposes a method for implementing PON compatibility based on the optical line terminal card provided in the above embodiments. Please refer to the flowchart for a schematic diagram. Figure 4 As shown, the specific steps include the following:

[0059] S401, the switch controller detects the current operating mode of the optical module port.

[0060] In this embodiment of the invention, the working modes of the optical module port include GPON mode and 10G PON mode. The state of the switching switch is different depending on the working mode.

[0061] The following steps are included before the switch controller detects the current operating mode of the optical module port:

[0062] S501, The switch controller obtains the identification information of the optical module;

[0063] S502. Determine the type of the optical module based on the identification information;

[0064] S503. Determine the working mode of the optical module port based on the judgment result.

[0065] In step S501, the switch controller and the optical module can be connected via the I2C bus. The switch controller can obtain the identification information of the optical module port through the I2C bus. The specific identification information of the optical module can be the optical module Serial ID.

[0066] In this embodiment of the invention, the type of optical module corresponds to its working mode. For example, optical modules include GPON optical modules, 10G PON optical modules, etc. Therefore, the working mode of the optical module port can be determined according to the type of optical module.

[0067] S402, The switch controller controls the switching switch to be turned on or off according to the working mode.

[0068] In this embodiment of the invention, the optical module and the MAC module are connected via differential lines. A series resistor is set on the differential line on the optical module side to attenuate the signal to meet the reception requirements of the MAC module. Specifically, the series resistors are R1 and R2. A coupling capacitor is set on the differential line on the MAC module side to transmit the AC signal from the previous stage to the next stage. While transmitting the AC signal, the DC signal is blocked, so that the operating points of the previous and next stages are not affected by each other.

[0069] The switching switch is located between the differential line and the pull-down resistor, and can support differential input; the switching switch is controlled by the switching controller; in this embodiment of the invention, the switching controller is a programmable logic device, the switching switch is an analog switch, and the switching controller is connected to the switching switch and controls the switching switch to be turned on or off.

[0070] S403. When the switch is turned on, the optical module output signal is attenuated by the series resistor and biased by the pull-down resistor before being sent to the MAC module.

[0071] S404. When the switch is off, the optical module output signal is attenuated by the series resistor and then sent to the MAC module.

[0072] In this embodiment of the invention, the operating modes of the optical module port include GPON mode and 10G PON mode. When the switch controller determines that the operating mode is GPON mode, the output of the optical module is equivalent to an LVPECL driver, and the MAC module is equivalent to a CML receiver. The circuit matching should meet the requirements of AC coupling from LVPECL to CML. The switch controller controls the switching switch to be turned on and connects a pull-down resistor to provide DC bias for LVPECL coupling. When the switch controller determines that the operating mode is 10G PON mode, the output of the optical module is equivalent to a CML driver, and the MAC module is equivalent to a CML receiver. The circuit matching should meet the requirements of AC coupling from CML to CML. At this time, the switch controller should control the output of the switching switch to a high-impedance state, that is, the switching switch should be turned off, to prevent packet loss due to the influence of the pull-down resistor on signal quality.

[0073] It should be noted that the series resistors are set to meet the LVPECL input voltage requirements that the CML receiver can tolerate; at the same time, in order to ensure that the series resistors have little impact on the CML input voltage amplitude and can meet the normal transmission in GPON mode, the resistance value of each series resistor is generally no greater than 24.9Ω.

[0074] It should be noted that the optical module output is an RD output, and the MAC module is an FPP chip.

[0075] The method for PON compatibility provided in this invention detects the current operating mode of the optical module port through a switch controller. The switch controller controls a switching switch to be on or off according to the operating mode. When the switching switch is on, the optical module output signal is attenuated by a series resistor and biased by a pull-down resistor before being sent to the MAC module. When the switching switch is off, the optical module output signal is attenuated by a series resistor before being sent to the MAC module. In some implementations, different PON technologies can be compatiblely implemented on a single OLT line card, greatly simplifying hardware development and design, reducing equipment investment costs, flexibly ensuring actual usage needs, and effectively reducing the system upgrade and maintenance costs for operators, achieving a smooth upgrade.

[0076] The above description, in conjunction with specific implementation methods, provides a further detailed explanation of the embodiments of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. An optical line terminal block, comprising: Optical module, MAC module, switch, switch controller, series resistor and pull-down resistor; The optical module and the MAC module are connected to form a first connection line, and the series resistor is provided on the optical module side of the first connection line; the pull-down resistor is connected to the first connection line through a second connection line, and the switching switch is provided on the second connection line and located between the first connection line and the pull-down resistor. The switch controller is connected to the optical module and the switching switch respectively; The connection between the switch controller and the optical module includes: the switch controller is connected to the optical module via an I2C bus, and the I2C bus is used to read the Serial ID of the optical module; The resistance value of the series resistor is less than or equal to 24.9 ohms, and the pull-down resistor is a DC bias resistor.

2. The optical line terminal block as described in claim 1, characterized in that, The optical line terminal card also includes a coupling capacitor; the coupling capacitor is disposed on the first connection line on the MAC module side.

3. The optical line terminal block as described in claim 1, characterized in that, The MAC module is an FPP chip.

4. The optical line terminal block as described in claim 1, characterized in that, The optical module includes an optical interface, which is a compatible interface.

5. The optical line terminal block as described in claim 1, characterized in that, The first connection line includes a first physical line and a second physical line, and the first physical line and the second physical line are differential lines. The series resistor provided on the optical module side of the first connection line includes: The series resistors are respectively set on the optical module side of the first physical line and the second physical line.

6. The optical line terminal block as described in claim 1, characterized in that, The switch controller is a programmable logic device, and the switching switch is an analog switch.

7. A method compatible with PON functionality, comprising: The switch controller detects the current operating mode of the optical module port; The switch controller controls the switching switch to be turned on or off according to the operating mode; The switch controller is connected to the optical module via an I2C bus, which is used to read the Serial ID of the optical module. When the switching switch is turned on, the optical module output signal is attenuated by the series resistor and biased by the pull-down resistor before being sent to the MAC module. When the switch is turned off, the optical module output signal is attenuated by the series resistor and then sent to the MAC module; The resistance value of the series resistor is less than or equal to 24.9 ohms, and the pull-down resistor is a DC bias resistor.

8. The method for PON compatibility as described in claim 7, characterized in that, Before the switch controller detects the current operating mode of the optical module port, it also includes: The switch controller acquires the identification information of the optical module port; The type of the optical module is determined based on the identification information; The operating mode of the optical module port is determined according to the type of the optical module.

9. The method for PON compatibility as described in claim 7, characterized in that, The operating modes include GPON mode and 10G PON mode; Controlling the switching switch to be on or off according to the operating mode includes: When the operating mode is GPON mode, the control switch is turned on; When the operating mode is 10G PON mode, the control switch is turned off.

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