JP6540957B2 - PON system and transmission method - Google Patents

Description

  The present invention relates to a PON (Passive Optical Network) system and transmission method for realizing optical fiber transmission.

  In recent years, as the speed of the radio access network provided by the mobile communication network is increased, the area (cell) covered by the base station apparatus becomes narrower, and as a result, the number of base station apparatuses to be installed to configure the mobile communication network. Is increasing. For this reason, as a network for accommodating a plurality of base station apparatuses, a passive optical network (PON: Passive Optical Network) system in which one optical transmission path is shared by a plurality of subscribers has been studied.

  In the PON system, one optical transmission line terminal (OLT: Optical Line Terminal) installed at a station of a telecommunications carrier is connected to a plurality of subscriber home terminals (ONUs: Optical Network Unit) via an optical splitter. It is done. The OLT realizes high bandwidth utilization efficiency by dynamically allocating an upstream band to a plurality of ONUs, for example, 64 ONUs by a time division multiplexing method.

  In the base station apparatus, time synchronization between the base station apparatuses is essential in order to realize handover and the like of the communication terminal. Conventionally, it has been common to install a GPS (Global Positioning System) antenna in each base station apparatus to receive reference time information. However, there have been cases in which the GPS antenna can not be installed due to restrictions such as the installation environment in the base station apparatus.

  Therefore, a loopback method has been proposed in which a single ONU under the OLT acquires a GPS signal, time information is provided from the ONU to the OLT side, and the time information is distributed to all other ONUs via the OLT. According to this, it is possible to flexibly cope with the case where the GPS antenna can not be installed in the base station apparatus. The time information included in the GPS signal may be configured to transmit a PON section on a packet basis such as IEEE 1588 v2 PTP (Precision Time Protocol) described in Non-Patent Document 1.

JP, 2014-165557, A

IEEE Std 1588-2008, "IEEE Standard for a Precision Clock Synchronization Protocol for Network Measurement and Control Systems," 2008.

  However, the technique described in Non-Patent Document 1 operates on the assumption that the upper and lower transmission delays of the master device providing the reference time and the slave device subordinate to and synchronized with the time provided by the master device are the same. . Therefore, when the IEEE 1588 v2 is applied to a PON system in which the transmission delay is asymmetric in the vertical direction, the time synchronization accuracy is degraded.

  Further, in the technology described in Patent Document 1, in consideration of the asymmetry of uplink and downlink transmission delays, the OLT identifies a PTP packet and adds a delay to the downlink PTP packet, whereby uplink and downlink are identified. The downlink transmission delay is symmetrical. However, this method can not be applied to the existing system because the OLT needs to have new functions such as a function of identifying PTP packets and a function of adding a delay.

  Also, as a method that does not change the existing OLT side, in order to transmit a PTP packet, the uplink fixed time slot is allocated to the ONU, thereby achieving stabilization of delay, and between the PTP master device and the PTP slave device. In PTP packet transmission, it is conceivable to achieve symmetry between upstream and downstream transmission delays of PTP packet transmission by intentionally delaying the transmission timing of the ONU in the transmission direction with a small transmission delay.

  However, when allocating a fixed time slot to an ONU, if the PTP packet interval reaching the master ONU (the ONU that receives PTP packets from the PTP master apparatus) from the PTP master apparatus does not match the fixed time slot interval of the master ONU: Jitter occurs in the PTP packet, making time synchronization difficult. In addition, in the transmission between the PTP master device and the PTP slave device, when a delay is intentionally added to the transmission direction with a small transmission delay, the master ONU sends an ONU via the OLT as an RTT (Round Trip Time) 1 If the delay time when PTP packets arrive is adjusted, the delay when PTP packets arrive from the ONU to the master ONU also changes as RTT 2 and time synchronization becomes difficult .

  The present invention has been made in view of such circumstances, and a PON in which an upstream PTP packet is received by a master ONU, time information is provided to an OLT side, and is distributed to all other ONUs through the OLT. An object of the present invention is to provide a PON system and transmission method capable of maintaining high accuracy of time synchronization regardless of asymmetry of transmission delay in the PON section in the system.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the PON system of the present invention is a PON (Passive Optical Network) that realizes optical fiber transmission of point-to-multipoint connection between an OLT (Optical Line Terminal) and a plurality of ONUs (Optical Network Units). A master ONU (Optical Network Unit) that acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from a GPS signal; It connects with the master ONU and the slave ONU via at least one slave ONU other than the master ONU and the optical branching device, and dynamically upstream bandwidths by the time division multiplexing method for the master ONU and the slave ONU. Assign an OLT (Optical Line Terminal), apply a synchronization system (802.1AS etc.) in the PON section, and The synchronization is performed, and time information transmitted from the master ONU via the OLT is notified to the master ONU or a communication apparatus under the slave ONU, or the time information acquired by the master ONU is the master ONU Communication devices under the control of the network.

  As described above, the synchronization system is applied in the PON section to perform time synchronization, and the time information transmitted from the master ONU via the OLT is notified to the master ONU or the communication apparatus under the slave ONU, or Since the time information acquired by the master ONU is notified to the communication apparatus subordinate to the master ONU, high accuracy of time synchronization can be maintained regardless of the asymmetry of the transmission delay of the PON section.

  (2) Further, in the PON system of the present invention, the master ONU compares the time of its own device with the reference time of the PTP packet, notifies the time difference to the OLT, and the OLT notices the notified time The time of its own device is adjusted using the difference, and a synchronization system (802.1 AS etc.) is applied to synchronize the time of the master ONU and the slave ONU with the time of its own device, and the slave ONU The PTP packet generated based on the acquired time information, PPS (Pulse per Second) and ToD (Time of Day), or a GPS pseudo signal is transmitted to the PTP slave device under the control, and the PTP slave device transmits the signal from the slave ONU Adjust the time of the own device using the time information indicated in the acquired PTP packet, PPS and ToD, or GPS pseudo signal, Alternatively, a PTP basic sequence may be performed with the slave ONU to perform time synchronization.

  As described above, the master ONU compares the time of its own device with the reference time of the PTP packet, notifies the time difference to the OLT, and the OLT uses its notified time difference to notify the own device of its own The time is adjusted, and a synchronization system (such as 802.1AS) is applied to synchronize the time of the master ONU and the slave ONU with the time of the own device, and the slave ONU is generated based on the time information acquired from the OLT Transmits a PTP packet, PPS (Pulse per Second) and PDS (Time of Day), or a GPS pseudo signal to a subordinate PTP slave device, the PTP slave device comprising a PTP packet, PPS and ToD acquired from the slave ONU. Or, adjust the time of the own device using the time information indicated in the GPS pseudo signal, or with the slave ONU Since time synchronization is performed by executing a PTP basic sequence, time is applied by applying a synchronization system that functions on the assumption that upper and lower transmission delays are symmetrical regardless of whether the transmission delay in the PON section is asymmetric or not. It is possible to perform synchronization.

  (3) Further, in the PON system of the present invention, the PTP packet transmitted to the PTP slave device when the slave ONU can not ignore the transmission delay between the own device and the PTP slave device or a subordinate base station device. , PPS and ToD, or GPS pseudo signals.

  As described above, when the delay ONU can not ignore the delay in the transmission between itself and the PTP slave device or the subordinate base station device, the PTP packet, PPS and ToD, or GPS pseudo to be transmitted to the PTP slave device. Since the delay time is added to the signal, it becomes possible to perform time synchronization in consideration of the delay.

  (4) Further, in the PON system of the present invention, when the master ONU can not ignore the delay of transmission between its own device and the subordinate communication device, it transmits PTP packet, PPS and ToD, or to the subordinate communication device A delay time is added to the GPS pseudo signal.

  As described above, the master ONU adds a delay time to the PTP packet, PPS and ToD, or GPS pseudo signal to be transmitted to the subordinate communication apparatus when the transmission delay between the own ONU and the subordinate communication apparatus can not be ignored. Therefore, it becomes possible to perform time synchronization in consideration of delay.

  (5) Further, in the PON system of the present invention, time synchronization is performed by applying a synchronization system (802.1 AS or the like), and the slave ONU receives the time when the PTP packet arrives at the master ONU and the OLT. The difference information with the time when the PTP packet arrived at the own device is reflected in the time information of the PTP packet and the PTP packet is transmitted to the PTP slave device under the control, or the difference information with the PTP packet is the PTP slave under the control When transmitting to the device and the PTP slave device acquires the PTP packet in which the difference information is reflected in the time information from the slave ONU, the PTP slave device uses the time information indicated in the acquired PTP packet. Adjust the time or execute PTP basic sequence with the slave ONU to perform time synchronization, Alternatively, when the differential information is acquired from the slave ONU together with the PTP packet, the differential information is reflected on the time information indicated in the acquired PTP packet to adjust the time of the own apparatus.

  As described above, time synchronization is performed by applying a synchronization system (802.1 AS or the like), and the slave ONU receives the PTP packet at the master ONU, and the PTP packet arrives at the slave ONU via the OLT. The difference information with respect to the time when the PTP packet is reflected to the time information of the PTP packet and the PTP packet is transmitted to the subordinate PTP slave device, or the difference information is transmitted together with the PTP packet to the subordinate PTP slave device, and the PTP slave When the device acquires a PTP packet in which the difference information is reflected in time information from the slave ONU, the device adjusts the time of the own device using the time information indicated in the acquired PTP packet, or the slave Execute PTP basic sequence with ONU to synchronize time, or PTP packet When the time information is acquired from the slave ONU along with the time information indicated in the acquired PTP packet to adjust the time of the own apparatus, the transmission delay in the PON section is asymmetric. Regardless of whether or not it is possible to perform time synchronization by applying a synchronization system that functions on the assumption that upper and lower transmission delays are symmetrical.

  (6) Further, in the PON system of the present invention, the slave ONU adds a delay time to the PTP packet to be transmitted to the PTP slave device if the transmission delay between its own device and the PTP slave device can not be ignored. It is characterized by

  As described above, when the delay ONU can not ignore the delay of the transmission between itself and the PTP slave device, the delay ONU adds a delay time to the PTP packet to be transmitted to the PTP slave device. It will be possible to do.

  (7) Further, in the PON system of the present invention, the master ONU adds a delay time to the PTP packet to be transmitted to the subordinate communication apparatus when the transmission delay between the own apparatus and the subordinate communication apparatus can not be ignored. It is characterized by

  As described above, when the master ONU can not ignore the delay of transmission between its own device and the subordinate communication device, it adds a delay time to the PTP packet to be transmitted to the subordinate communication device, so time synchronization considering delay is taken. It will be possible to do.

  (8) Further, according to the transmission method of the present invention, a PON (Point-to-Multi Point) optical fiber transmission is realized between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs). A transmission method of a Passive Optical Network) system, in which a master ONU (Optical Network Unit) acquires time information from a GPS (Global Positioning System) signal, or is generated based on time information acquired from a GPS signal PTP packets are received, time synchronization is performed by applying a synchronization system (802.1 AS or the like) in the PON section, and the optical ONU is connected to the master ONU and slave ONUs other than the master ONU via the optical splitter. Transmission via an OLT (Optical Line Terminal) that dynamically allocates an upstream band to a master ONU and the slave ONU by time division multiplexing The notified time information is notified to the master ONU or a communication device subordinate to the slave ONU, or the time information acquired by the master ONU is notified to a communication device subordinate to the master ONU.

  As described above, the master ONU acquires time information from the GPS signal or receives a PTP packet generated based on the time information acquired from the GPS signal, and applies a synchronization system (802.1 AS or the like) in the PON section. Time synchronization is performed, and the master ONU and the slave ONU other than the master ONU are connected via the optical splitter and dynamically upstreamed by the time division multiplexing method for the master ONU and the slave ONU. The time information transmitted via the OLT for allocating a band is notified to the master ONU or the communication device subordinate to the slave ONU, or the time information acquired by the master ONU to the communication device subordinate to the master ONU Notification, regardless of whether the transmission delay in the PON section is asymmetric or not, It is possible to perform time synchronization by applying a synchronization system that functions on the premise that the spread is symmetrical.

  According to the present invention, it is possible to perform time synchronization by applying a synchronization system that functions on the premise that upper and lower transmission delays are symmetrical regardless of whether the transmission delay in the PON section is asymmetric or not. Become.

FIG. 1 is a diagram showing a schematic configuration of a PON system according to an embodiment of the present invention. It is a figure which shows the time synchronization sequence between the PTP master apparatus-PTP slave apparatus of IEEE 1588v2. FIG. 7 is a diagram showing a mechanism of time information transmission to the PTP slave device according to the first embodiment. FIG. 7 is a diagram showing a mechanism of time information transmission to a PTP slave device according to a second embodiment.

  That is, the PON system of the present invention is a PON (Passive Optical Network) that realizes optical fiber transmission of point-to-multipoint connection between an OLT (Optical Line Terminal) and a plurality of ONUs (Optical Network Units). A master ONU (Optical Network Unit) that acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from a GPS signal; It connects with the master ONU and the slave ONU via at least one slave ONU other than the master ONU and the optical branching device, and dynamically upstream bandwidths by the time division multiplexing method for the master ONU and the slave ONU. Assign an OLT (Optical Line Terminal), apply a synchronization system (802.1AS etc.) in the PON section, and The synchronization is performed, and time information transmitted from the master ONU via the OLT is notified to the master ONU or a communication apparatus under the slave ONU, or the time information acquired by the master ONU is the master ONU Communication devices under the control of the network.

  Thus, the present inventors apply time synchronization by applying a synchronization system that functions on the premise that upper and lower transmission delays are symmetrical regardless of whether the transmission delay in the PON section is asymmetric or not. Made possible. Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a PON system according to an embodiment of the present invention. As shown in FIG. 1, in this PON system, a total of n (n is an arbitrary integer) ONUs 40-1 to 40-n are connected under the OLT 10 via an optical splitter (optical splitter) 30. There is. The PTP master device 50 is connected to the ONU 40-1, and the PTP master device 50 has a GPS antenna 51. Further, PTP slave devices 52-1 to 52- (n-1) are connected to the ONUs 40-2 to 40-n, respectively. Base station devices 60-1 to 60-n are connected to the PTP master device 50 and PTP slave devices 52-1 to 52- (n-1), respectively.

  The time information received by the GPS antenna 51 is distributed to the other ONUs 40-2 to 40-n via the PTP master device 50, the ONU 40-1, and the OLT 10. The time information may be distributed to the ONU 40-1 through the OLT 10.

FIG. 2 is a diagram showing a time synchronization sequence between the PTP master device and the PTP slave device of IEEE 1588v2. Sends a "Sync (t _1)" to the slave ONU master the ONU at the time _{t 1,} and arrived in time _{t 2} to the slave ONU. Slave ONU sends a "Delay_Req" to the master ONU at time _{t 3,} and it has arrived at the time _{t 4} to the master ONU. Also, it is assumed that the master ONU transmits “Delay_Resp (t ₄ )” at time t ₄ . In this case, the slave ONU can correct the time of its own device by calculating the time difference with the master ONU from the following equation.
_{(Delay) = {(t 2} -t 1) + (t 4 -t 3)} / 2

  In the first embodiment, a technique will be described that uses a synchronization function (802.1 AS or the like) in the PON section, and does not transmit a PTP packet and does not use a PTP basic sequence. The time difference may be transmitted to the OLT side using a PTP packet. FIG. 3 is a diagram showing a mechanism of time information transmission to the PTP slave device according to the first embodiment.

  (1) First, time synchronization is performed with high accuracy between the OLT and all ONUs using IEEE 802.1AS or the like.

  (2) Next, the master ONU compares the time of its own device with the reference time of the PTP packet (or 1PPS + ToD), and notifies the OLT of the time difference. The GM (PTP Grand Master) is connected to the master ONU, and the PTP slave device is connected to any of the slaves ONU 1 to N. Incidentally, there is also a case where a PTP slave device is connected under the master ONU. Then, when the delay in each section can not be ignored, the time difference information in consideration of the delay is notified.

  (3) The OLT adjusts its own time based on the time difference information from the master ONU.

  (4) The slave ONU (or master ONU) generates a PTP packet based on its own time locked to the OLT and transmits it to the PTP slave device. When the delay between the slave ONU and the PTP slave device can not be ignored, the delay is also reflected in the generated PTP packet. That is, the delay time is added to the time of the own device.

  (5) The PTP slave device adjusts its own time to the time information described in the received PTP packet. Alternatively, the slave ONU is regarded as a PTP master, and time synchronization is performed by the PTP basic sequence.

  As a result, regardless of whether the transmission delay in the PON section is asymmetric or not, time synchronization can be performed by applying a synchronization system that functions on the premise that the upper and lower transmission delays are symmetrical.

  In the second embodiment, a technique will be described that uses a synchronization function (802.1 AS or the like) in the PON section, transmits a PTP packet, and does not use a PTP basic sequence. FIG. 4 is a diagram showing a mechanism of time information transmission to the PTP slave device according to the second embodiment.

  (1) Time synchronization is performed with high accuracy between the OLT and all ONUs using IEEE 802.1AS or the like.

(2) ONU is, reflection time and _{t 1} that PTP packet has arrived to the master ONU, the difference information _t 2 -t ₁ and the time _{t 2,} which arrived in the slave ONU through the OLT, the time information of the PTP packet Do. The difference information t ₂ -t ₁ may be transmitted by another control packet or the like. Also, the GM is connected to the master ONU, and the PTP slave device is connected to any of the slave ONUs 1 to N. When the distance delay in each section can not be ignored, correction (delay correction) is performed in consideration of the amount of delay.

(2 ') slave ONU includes a time PTP packet arrived to the master ONU _{t 1,} the difference information _t 2 -t ₁ between the time _{t 2} that arrive slave ONU via the OLT, PTP slave with PTP packet Transmit to device. Here, as described above, the GM is connected to the master ONU, and the PTP slave device is connected to any of the slave ONUs 1 to N. However, when the distance delay in each section can not be ignored, the delay amount is also set. Make the correction (delay correction) considered.

  (3) The PTP slave device adjusts its own time to the time information described in the received PTP packet. Alternatively, the slave ONU is considered as a PTP master and synchronized by the PTP sequence.

  (3 ') Also, the PTP slave device may adjust its own time by reflecting the time difference information of (2') on the time information described in the received PTP packet.

  In transmission of a PTP packet that arrives at the slave ONU from the master ONU via the OLT, it is possible to reflect time information on the PTP once at the OLT and again at the slave ONU.

  As a result, regardless of whether the transmission delay in the PON section is asymmetric or not, time synchronization can be performed by applying a synchronization system that functions on the premise that the upper and lower transmission delays are symmetrical.

10 OLT
30 optical splitter (optical splitter)
40-1 Master ONU
40-2 to 40-n slave ONU
50 PTP master device 51 GPS antenna 52-1 to 52- (n-1) PTP slave device 60-1 to 60-n base station

Claims (11)

A PON (Passive Optical Network) system which realizes optical fiber transmission of point-to-multipoint (Point to Multi Point) connection between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs),
A master ONU (Optical Network Unit) that acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from a GPS signal;
At least one slave ONU other than the master ONU;
And an optical line terminal (OLT) that is connected to the master ONU and the slave ONU via an optical splitter and dynamically allocates an upstream bandwidth to the master ONU and the slave ONU by time division multiplexing. ,
Apply synchronization system in PON section and perform time synchronization,
The master ONU compares the time of its own device with the reference time of the PTP packet, and notifies the time difference to the OLT.
The OLT adjusts the time of its own device using the notified time difference, and applies a synchronization system to synchronize the time of the master ONU and the slave ONU with the time of its own device.
The slave ONU transmits a PTP packet generated based on time information acquired from the OLT, PPS (Pulse per Second) and ToD (Time of Day), or a GPS pseudo signal to a subordinate PTP slave device,
The PTP slave device adjusts the time of its own device using time information indicated in the PTP packet, PPS and ToD, or GPS pseudo signal acquired from the slave ONU, or performs PTP with the slave ONU. Execute basic sequence and synchronize time,
When the delay of transmission between the slave ONU and its own device and the PTP slave device or the subordinate base station device can not be ignored, the delay time to the PTP packet, PPS and ToD, or GPS pseudo signal transmitted to the PTP slave device A PON system characterized by adding A PON (Passive Optical Network) system which realizes optical fiber transmission of point-to-multipoint (Point to Multi Point) connection between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs),
A master ONU (Optical Network Unit) that acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from a GPS signal;
At least one slave ONU other than the master ONU;
And an optical line terminal (OLT) that is connected to the master ONU and the slave ONU via an optical splitter and dynamically allocates an upstream bandwidth to the master ONU and the slave ONU by time division multiplexing. ,
Apply synchronization system in PON section and perform time synchronization,
The master ONU compares the time of its own device with the reference time of the PTP packet, and notifies the time difference to the OLT.
The OLT adjusts the time of its own device using the notified time difference, and applies a synchronization system to synchronize the time of the master ONU and the slave ONU with the time of its own device.
The slave ONU transmits a PTP packet generated based on time information acquired from the OLT, PPS (Pulse per Second) and ToD (Time of Day), or a GPS pseudo signal to a subordinate PTP slave device,
The PTP slave device adjusts the time of its own device using time information indicated in the PTP packet, PPS and ToD, or GPS pseudo signal acquired from the slave ONU, or performs PTP with the slave ONU. time synchronization have line by running the basic sequence,
The master ONU is characterized by adding a delay time to a PTP packet, PPS and ToD, or GPS pseudo signal to be transmitted to the subordinate communication device, when the delay of transmission between the own ONU and the subordinate communication device can not be ignored. PON system. A PON (Passive Optical Network) system which realizes optical fiber transmission of point-to-multipoint (Point to Multi Point) connection between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs),
A master ONU (Optical Network Unit) that acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from a GPS signal;
At least one slave ONU other than the master ONU;
And an optical line terminal (OLT) that is connected to the master ONU and the slave ONU via an optical splitter and dynamically allocates an upstream bandwidth to the master ONU and the slave ONU by time division multiplexing. ,
Apply synchronization system in PON section and perform time synchronization,
The master ONU compares the time of its own device with the reference time of the PTP packet, and notifies the time difference to the OLT.
The OLT adjusts the time of its own device using the notified time difference, and applies a synchronization system to synchronize the time of the master ONU and the slave ONU with the time of its own device.
The slave ONU transmits a GPS pseudo signal generated based on time information acquired from the OLT to a subordinate PTP slave device,
The PTP slave device adjusts the time of its own device using time information indicated in the GPS pseudo signal acquired from the slave ONU, or executes a PTP basic sequence with the slave ONU to synchronize time. A PON system characterized by performing . A PON (Passive Optical Network) system which realizes optical fiber transmission of point-to-multipoint (Point to Multi Point) connection between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs),
A master ONU (Optical Network Unit) that acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from a GPS signal;
At least one slave ONU other than the master ONU;
And an optical line terminal (OLT) that is connected to the master ONU and the slave ONU via an optical splitter and dynamically allocates an upstream bandwidth to the master ONU and the slave ONU by time division multiplexing. ,
Apply synchronization system in PON section and perform time synchronization,
The slave ONU reflects the difference information between the time when the PTP packet arrives at the master ONU and the time when the PTP packet arrives at the own apparatus via the OLT in the time information of the PTP packet, and reflects the difference information Send to the subordinate PTP slave device,
The PTP slave device adjusts the time of its own device using the time information indicated in the acquired PTP packet, when the PTP packet in which the difference information is reflected in the time information is acquired from the slave ONU. PON system characterized by A PON (Passive Optical Network) system which realizes optical fiber transmission of point-to-multipoint (Point to Multi Point) connection between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs),
A master ONU (Optical Network Unit) that acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from a GPS signal;
At least one slave ONU other than the master ONU;
And an optical line terminal (OLT) that is connected to the master ONU and the slave ONU via an optical splitter and dynamically allocates an upstream bandwidth to the master ONU and the slave ONU by time division multiplexing. ,
Apply synchronization system in PON section and perform time synchronization,
The slave ONU reflects the difference information between the time when the PTP packet arrives at the master ONU and the time when the PTP packet arrives at the own apparatus via the OLT in the time information of the PTP packet, and reflects the difference information Send to the subordinate PTP slave device,
The PTP slave device executes a PTP basic sequence with the slave ONU using the slave ONU as a PTP master when the PTP packet in which the difference information is reflected in time information is acquired from the slave ONU A PON system characterized by performing synchronization. The slave ONU, when the transmission delay between the host device and the PTP slave device can not be ignored, according to claim 4 or claim 5, wherein the adding the delay time to the PTP packet to be transmitted to the PTP slave device PON system. 6. The master ONU according to claim 4 , wherein the delay time is added to the PTP packet to be transmitted to the subordinate communication device, when the delay of the transmission between the own ONU and the subordinate communication device can not be ignored. PON system. A transmission method of a PON (Passive Optical Network) system which realizes optical fiber transmission of point-to-multipoint (Point to Multi Point) connection between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs).
The master ONU (Optical Network Unit) acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from the GPS signal,
Apply synchronization system in PON section and perform time synchronization,
In an OLT (Optical Line Terminal), it is connected to the master ONU and slave ONUs other than the master ONU via an optical splitter, and dynamically connected to the master ONU and slave ONU by time division multiplexing. Allocate upstream bandwidth,
The master ONU compares the time of its own device with the reference time of the PTP packet, and notifies the time difference to the OLT.
The OLT adjusts the time of its own device using the notified time difference, and applies a synchronization system to synchronize the time of the master ONU and the slave ONU with the time of its own device.
The slave ONU transmits a PTP packet generated based on time information acquired from the OLT, PPS (Pulse per Second) and ToD (Time of Day), or a GPS pseudo signal to a subordinate PTP slave device,
The PTP slave device adjusts the time of its own device using time information indicated in the PTP packet, PPS and ToD, or GPS pseudo signal acquired from the slave ONU, or performs PTP with the slave ONU. Execute basic sequence and synchronize time,
When the delay of transmission between the slave ONU and its own device and the PTP slave device or the subordinate base station device can not be ignored, the delay time to the PTP packet, PPS and ToD, or GPS pseudo signal transmitted to the PTP slave device A transmission method characterized by adding A transmission method of a PON (Passive Optical Network) system which realizes optical fiber transmission of point-to-multipoint (Point to Multi Point) connection between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs).
The master ONU (Optical Network Unit) acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from the GPS signal,
Apply synchronization system in PON section and perform time synchronization,
In an OLT (Optical Line Terminal), it is connected to the master ONU and slave ONUs other than the master ONU via an optical splitter, and dynamically connected to the master ONU and slave ONU by time division multiplexing. Allocate upstream bandwidth,
The master ONU compares the time of its own device with the reference time of the PTP packet, and notifies the time difference to the OLT.
The OLT adjusts the time of its own device using the notified time difference, and applies a synchronization system to synchronize the time of the master ONU and the slave ONU with the time of its own device.
The slave ONU transmits a PTP packet generated based on time information acquired from the OLT, PPS (Pulse per Second) and ToD (Time of Day), or a GPS pseudo signal to a subordinate PTP slave device,
The PTP slave device adjusts the time of its own device using time information indicated in the PTP packet, PPS and ToD, or GPS pseudo signal acquired from the slave ONU, or performs PTP with the slave ONU. Execute basic sequence and synchronize time,
The master ONU is characterized by adding a delay time to a PTP packet, PPS and ToD, or GPS pseudo signal to be transmitted to the subordinate communication device, when the delay of transmission between the own ONU and the subordinate communication device can not be ignored. Transmission method. A transmission method of a PON (Passive Optical Network) system which realizes optical fiber transmission of point-to-multipoint (Point to Multi Point) connection between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs).
The master ONU (Optical Network Unit) acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from the GPS signal,
Apply synchronization system in PON section and perform time synchronization,
In an OLT (Optical Line Terminal), it is connected to the master ONU and slave ONUs other than the master ONU via an optical splitter, and dynamically connected to the master ONU and slave ONU by time division multiplexing. Allocate upstream bandwidth,
Apply synchronization system in PON section and perform time synchronization,
The slave ONU reflects the difference information between the time when the PTP packet arrives at the master ONU and the time when the PTP packet arrives at the own apparatus via the OLT in the time information of the PTP packet, and reflects the difference information Send to the subordinate PTP slave device,
The PTP slave device adjusts the time of its own device using the time information indicated in the acquired PTP packet, when the PTP packet in which the difference information is reflected in the time information is acquired from the slave ONU. Transmission method characterized by A transmission method of a PON (Passive Optical Network) system which realizes optical fiber transmission of point-to-multipoint (Point to Multi Point) connection between an Optical Line Terminal (OLT) and a plurality of Optical Network Units (ONUs).
The master ONU (Optical Network Unit) acquires time information from a GPS (Global Positioning System) signal or receives a PTP packet generated based on the time information acquired from the GPS signal,
Apply synchronization system in PON section and perform time synchronization,
In an OLT (Optical Line Terminal), it is connected to the master ONU and slave ONUs other than the master ONU via an optical splitter, and dynamically connected to the master ONU and slave ONU by time division multiplexing. Allocate upstream bandwidth,
Apply synchronization system in PON section and perform time synchronization,
The slave ONU reflects the difference information between the time when the PTP packet arrives at the master ONU and the time when the PTP packet arrives at the own apparatus via the OLT in the time information of the PTP packet, and reflects the difference information Send to the subordinate PTP slave device,
The PTP slave device executes a PTP basic sequence with the slave ONU using the slave ONU as a PTP master when the PTP packet in which the difference information is reflected in time information is acquired from the slave ONU A transmission method characterized in that synchronization is performed.

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