WO2008072347A1 - Pon system and pon connection method - Google Patents

Abstract

A PON system incorporating a new PON having an up-link transmission rate and a down-link transmission rate different from respective those of the existing PON in an optical access network used by an existing PON. In the PON system, a new PON2X transmits/receives a down-link signal having a wavelength λ3 different from that of the existing PON1 and an up-link signal having the same wavelength λ1 as that of the existing PON1. A 1G-OLT (10) of the existing PON1 has a PON control section (17) performs band control so that it opens a predetermined time of the up-link band of the existing PON1 when controlling the up-link band of the existing PON1 as a band for the new PON2X and it does not assign the open time to the up-link band of the existing PON1. A 10G-OLT (20X) of the new PON has a no-signal section detecting section (29) for detecting the open time and a PON control section (27) for assigning the detected open time to the up-link band of the new PON2X.

Description

 Specification

 PON system and PON connection method

 Technical field

 [0001] The present invention relates to a PON system and a PON connection method for accommodating a new PON having a transmission rate different from that of an existing PON in an optical access network used by the existing PON.

 Background art

 [0002] In recent years, the development of technology related to PON (Passive Optical Network) in which a branching device (splitter) is inserted in the middle of an optical fiber network and one optical fiber is drawn into a plurality of subscriber-side devices has been promoted. Yes. In this PON, a PON system that transfers data at a signal speed of lGbps (Giga Bit Per Second) in both upstream and downstream is now widespread. However, when the transmission capacity required by the user is insufficient, a PON system with a higher uplink / downlink speed than the current transmission speed (for example, a 10G-PON system that transmits at an uplink / downstream lOGbps signal rate). ) Is required. Since the required bandwidth of users depends on the usage situation of each user, the transition to a new PON (for example, the transition from 1G-PON to 10G-PON) proceeds on a subscriber basis.

 [0003] In an asymmetric PON system in which the uplink and downlink transmission rates are different, there is a technique for accommodating (entering) a subscriber-side device with a high uplink speed in an existing PON system. In the passive optical network PON described in Patent Literature 1, the low-speed signal and the high-speed signal are time-divisioned because the station side device has two types of bit synchronization circuit for low speed and bit synchronization circuit for high speed in the upstream direction. It is possible to receive the uplink signal. Then, the new subscriber-side device with the increased uplink speed transmits the uplink signal at a signal rate that is a constant multiple of the uplink transmission rate of the existing subscriber-side device in the allocated uplink time zone. . As a result, the control signal multiplexed on the downlink signal has a common format for the existing subscriber side device and the new subscriber side device. In addition, the PON system described in Patent Document 2 lays a spare fiber in advance, and provides service upgrades at different wavelengths in the PON.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-33537 Patent Document 2: US Patent No. 7095958

 Disclosure of the invention

 Problems to be solved by the invention

 However, in the former and the latter prior arts described above, a plurality of (for example, 32) subscriber-side devices are cascade-connected to one station-side device in the PON. It is not possible to replace only one of the devices with a new PON system subscriber side device. For this reason, in order to change all the subscriber side equipment belonging to the PON at the same time, there was a problem that the construction at the entrance of the entrance had to be done at the same time.

 [0006] In addition, the former prior art has a problem in that it is impossible to allow a subscriber-side device that has a high speed in the downstream direction as well as a speed in the upstream direction to enter the existing PON system. . Further, in the latter prior art, since it is not possible to replace devices in units of subscriber side devices unless a spare fiber network is laid in advance, the configuration of the PON system is complicated and the fiber connection is reduced. There was a problem that the cost and time of the net laying work were increased.

 The present invention has been made in view of the above, and provides a PON system and a PON connection method in which replacement of each subscriber side device with a new PON system can be easily performed with a simple configuration. With the goal.

 Means for solving the problem

[0008] In order to solve the above-described problems and achieve the object, the present invention relates to an existing PON that is different from the existing PON as a transmission rate in the downlink direction and the uplink direction. In the PON system accommodated in the optical access network, the new PON transmits / receives a downstream signal at a different wavelength from that of the existing PON, and an upstream signal The station device on the existing PON transmits / receives at the same wavelength as the PON, and performs a bandwidth control in the upstream direction of the existing PON when the station side device of the existing PON uses a predetermined time zone in the upstream bandwidth of the existing PON. The first PON control unit includes a first bandwidth control unit that controls the bandwidth so that the open time zone that is released as a bandwidth is not allocated to the upstream bandwidth of the existing PON, and the station device on the new PON includes the first bandwidth Detecting when the control unit is open And the part, open the time zone in which the detection unit has detected the new And a second bandwidth control unit that allocates to the upstream bandwidth of the PON. The invention's effect

 [0009] According to the present invention, the predetermined time zone of the upstream bandwidth of the existing PON is released as a new PON bandwidth, and the released time zone is allocated to the upstream bandwidth of the new PON. A new PON with different transmission speeds can be easily accommodated with a simple configuration in the optical access network used by the existing PON.

 Brief Description of Drawings

 FIG. 1 is a block diagram showing a configuration of a PON system according to Embodiment 1.

 [FIG. 2] FIG. 2 is a diagram showing a configuration of a PON system when only an existing PON system exists.

 [FIG. 3] FIG. 3 is a diagram showing a configuration of a PON system when an existing PON system and a new PON system exist.

 FIG. 4 is a diagram showing a configuration of a PON system when only a new PON system exists.

 FIG. 5 is a timing chart showing the operation timing of the PON system shown in FIG. 2.

 [FIG. 6] FIG. 6 is a diagram for explaining a time zone in which the PON system shown in FIG. 3 permits data transmission allocated to the existing PON system.

 FIG. 7 is a timing chart showing the operation timing of the PON system shown in FIG.

 [FIG. 8] FIG. 8 is a timing chart showing the operation timing of the existing PON system shown in FIG.

 [FIG. 9] FIG. 9 is a timing chart showing the operation timing of the new PON system shown in FIG.

 FIG. 10 is a block diagram showing a configuration of a PON system according to Embodiment 2.

 FIG. 11 is a block diagram showing a configuration of a PON system according to Embodiment 3.

[FIG. 12] FIG. 12 is a timing chart showing the operation timing of the PON system shown in FIG. FIG. 13 is a timing chart showing the discovery procedure of the PON system shown in FIG.

 FIG. 14 is a timing chart showing timings of transmission permission signals transmitted by the PON system shown in FIG.

 FIG. 15 is a timing chart showing the discovery procedure of the PON system shown in FIG.

Explanation of symbols

 1 Existing PON system

 2X, 2Y, 2Z New PON system

 5X, 5Y, 5Z PON system

 10 1G -OLT

 11, 21, 31, 41, 61 WDM

 12, 22, 32, 42, 62 EZO converter

 13, 23, 33, 43, 63a, 63b, 71

 14, 24 Burst synchronization section

 15, 25, 35, 45 MUX 咅

 16, 26, 36, 46 DMUX 咅

 17, 27, 37, 47 PON control

 18, 28 Network interface

 20X, 20Y, 20Z 10G-

29 No signal section detector

 30 1G-ONU

 38, 48 User interface

 40 10G-ONU

 50 Optical branching network

 51 optical fiber

 60 pseudo ONU

67 10G— PON control unit 69 1G— PON control unit

 70 No signal section detector

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of a PON system and a PON connection method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

 Embodiment 1.

 FIG. 1 is a block diagram showing a configuration of the PON system according to the first embodiment. The PON system 5X has an existing PON system 1 that is an existing PON system and a new PON system 2X that is a new PON system. Here, the case where the existing PON system 1 is a bi-directional lGbps 1G-PON system and the new PON system 2X is a bi-directional lOGbps 10G-PON system will be described.

 In the present embodiment, a new PON system 5X is configured by adding a new PON system 2X to the existing PON system 1 configuring the PON system 5X. Here, a case will be described in which the first PON system 5X is configured with only the existing PON system 1, the new PON system 2X is added, and finally the PON system 5X is configured with only the new PON system 2X.

 [0015] FIG. 1 shows the configuration of the PON system 5X in a state where a new PON system 2X is added to the PON system 5X configured only by the existing PON system 1! /. The existing PON system 1 is composed of 1G-OLT10, 1G-ONU30 (2) to 1G-ONU30 (n) (n is a natural number), and optical branch network (optical access network) 50. The new PON system 2X includes 10G-OLT20X, 10G-ONU40 (1), and optical branch network 50. The optical branch network 50 is a 2-input n-output optical branch network, and connects the new PON system 2X and the existing PON system 1.

First, the configuration of the 1G-OLT 10 will be described. 1G—OLT10 is a station-side device of the existing PON system 1. WDM (optical transceiver) 11, EZO converter 12, OZE converter 13, burst synchronizer 14, MUX 15, DMUX 16, PON control Part 17 and network interface part 18. A WDM (Wavelength Division Multiplexing) 11 is connected to the optical branching network 50 and to the EZO conversion unit 12 and the OZE conversion unit 13. The EZO conversion unit 12 is connected to the MUX unit 15, and the O / E conversion unit 13 is connected to the DMUX unit 16 via the burst synchronization unit 14.

 [0018] The MUX unit 15 and the DMUX unit 16 are connected to the PON control unit 17 and the network interface unit 18, respectively. WDM11 multiplexes the optical signal in the upstream direction (direction from ONU to OLT) (optical demultiplexing), and multiplexes the optical signal in the downstream direction (direction from OLT to ONU) (optical multiplexing).

 [0019] The EZO converter (λ 2) χ) 12 converts the signal from the MUX unit 15 into a downlink signal with a wavelength λ 2 by ΕΖ O (Electric to Optical) and transmits the signal via the WDM 11 in the downlink direction. The OZE conversion unit (λlRx) 13 performs Ο / E (Optical to Electric) conversion on the upstream signal (burst optical signal) of wavelength λ1 received by the WDM 11 and inputs it to the burst synchronization unit 14.

 The burst synchronization unit 14 takes bit synchronization of the upstream signal OZE-converted by the OZE conversion unit 13 and inputs it to the DMUX unit 16. The DMUX unit 16 separates the uplink signal from the burst synchronization unit 14 into an uplink PON control signal and user data. The DMUX unit 16 inputs the separated PON control signal to the PON control unit 17 and inputs the separated user data to the network interface unit 18. The MUX unit 15 multiplexes the downstream PON control signal (signal for controlling the PON system 5X) from the PON control unit 17 and user data from the network interface unit 18 and inputs the multiplexed data to the EZO conversion unit 12.

 The PON control unit 17 generates a PON control signal to be sent to the 1G-ONU and inputs it to the MUX unit 15. The PON control unit 17 receives the PON control signal sent through the 1G-ONU power via the MUX unit 15. The PON control unit 17 controls the operation of the 1G-OLT 10 based on the PON control signal generated by itself and the PON control signal from the 1G-ON U.

 [0022] The network interface unit 18 is a communication interface connected to an external device (not shown). The network interface unit 18 inputs user data sent from the external device to the MUX unit 15 and transmits user data sent from the DMUX unit 16 to the external device.

[0023] Next, the configuration of the 1G-ONU30 (2) will be described. 1G— ONU30 (2) is existing It is a subscriber-side device of the PON system 1 and includes a WDM 31, an EZO conversion unit 32, a 0 / E conversion unit 33, a MUX unit 35, a DMUX unit 36, a PON control unit 37, and a user interface unit 38.

 The WDM 31 is connected to the optical branch network 50 and to the EZO conversion unit 32 and the 0 / E conversion unit 33. The EZO conversion unit 32 is connected to the MUX unit 35, and the 0 / E conversion unit 33 is connected to the DMUX unit 36. The MUX unit 35 and the DMUX unit 36 are connected to the PON control unit 37 and the user interface unit 38, respectively.

 [0025] WDM31, EZO conversion unit 32, 0 / E conversion unit 33, MUX unit 35, DMUX unit 36, PON control unit 37, user interface unit 38 are WDM11, EZO conversion unit 12, OZE conversion unit 13, respectively. It has the same functions as the MUX unit 15, DMUX unit 16, PON control unit 17, and network interface unit 18.

 That is, the WDM 31 multiplexes the optical signal in the upstream direction (optical multiplexing) and multiplexes the optical signal in the downstream direction (optical demultiplexing). The EZO conversion unit (λΙΤχ) 32 performs EZO conversion of the signal from the MUX unit 35 into an upstream signal of wavelength λ1, and transmits the upstream signal via the WDM 31. The OZE conversion unit (λ 2Rx) 33 performs 下 り / Ε conversion on the downstream signal (burst optical signal) of wavelength λ 2 received by the WDM 31 and inputs it to the DMUX unit 36.

 The MUX unit 35 multiplexes the uplink PON control signal from the PON control unit 37 and the user data from the user interface unit 38 and inputs the multiplexed data to the EZO conversion unit 32. The DMUX unit 36 separates the downlink signal from the OZE conversion unit 33 into a downlink PON control signal and user data. The DMUX unit 36 inputs the separated PON control signal to the PON control unit 37 and inputs the separated user data to the user interface unit 38.

 [0028] The PON control unit 37 generates a PON control signal to be sent to the 1G-OLT 10 and inputs it to the MUX unit 35. The PON control unit 37 receives the PON control signal sent from the 1G-OLT 10 via the DM UX unit 36, and analyzes the received PON control signal. The PON control unit 37 controls the operation of the 1 G ONU 30 (2) based on the PON control signal generated by itself and the PON control signal from the 1G-OLT 10.

[0029] The user interface unit 38 is a communication interface connected to an external device (not shown). The user interface unit ₃₈ transmits user data sent from an external device to the MUX. The user data sent from the DMUX unit 36 is transmitted to the external device. 1G-ONU30 (3) to 1G-ONU30 (n), 1G-ONU30 (1), which will be described later, have the same configuration as 1G-ONU30 (2).

 [0030] Next, the configuration of the 10G-OLT20X will be described. 10G—OLT20X is a new PON system 2X station side equipment, WDM21, EZO converter 22, 0 / E converter 23, burst synchronization unit 24, MUX unit 25, DMUX unit 26, PON control unit 27, network An interface unit 28 and a no-signal section detection unit 29 are provided.

 The WDM 21 is connected to the optical branch network 50 and to the EZO conversion unit 22 and the 0 / E conversion unit 23. The E / O conversion unit 22 is connected to the MUX unit 25, and the O / E conversion unit 23 is connected to the DMUX unit 26 via the burst synchronization unit 24. The MUX unit 25 and the DMUX unit 26 are connected to the PON control unit 27 and the network interface unit 28, respectively. Further, the no-signal section detection unit 29 which is the main feature of the present invention is connected to the PON control unit 27 and the OZE conversion unit 23.

 The no-signal section detection unit 29 detects the no-signal section from the upstream signal power from the OZE conversion unit 23 and notifies the PON control unit 27 of it. That is, the WDM 21 multiplexes the optical signal in the upstream direction (optical demultiplexing) and multiplexes the optical signal in the downstream direction (optical multiplexing).

 [0033] WDM21, EZO conversion unit 22, OZE conversion unit 23, burst synchronization unit 24, MUX unit 25, D MUX unit 26, PON control unit 27, network interface unit 28 are WDM 1 1, EZO conversion unit 12, It has the same functions as the OZE conversion unit 13, the burst synchronization unit 14, the MUX unit 15, the DMUX unit 16, the PON control unit 17, and the network interface unit 18.

 [0034] The EZO conversion unit (λ 3 Τχ) 22 converts the signal from the MUX unit 25 into a downlink signal of wavelength λ 3 and transmits it in the downlink direction via the WDM 21. ΟΖΕConversion unit (λlRx) 23 OZE-converts the upstream signal (burst optical signal) of wavelength λ1 received by WDM 21 and inputs it to burst synchronization unit 24 and no-signal section detection unit 29.

The burst synchronization unit 24 takes bit synchronization of the upstream signal OZE-converted by the OZE conversion unit 23 and inputs the bit synchronization to the DMUX unit 26. The DMUX unit 26 separates the uplink burst signal from the burst synchronization unit 24 into an uplink PON control signal and user data. The DMUX unit 26 inputs the separated PON control signal to the PON control unit 27 and transmits the separated user data to the network Input to interface section 28. The MUX unit 25 multiplexes the downstream PON control signal from the PON control unit 27 and the user data from the network interface unit 28 and inputs the multiplexed data to the EZO conversion unit 22.

 [0036] The PON control unit 27 generates a PON control signal to be sent to the 10G-ONU 40 (1) and inputs it to the MUX unit 25. The PON control unit 27 receives the PON control signal sent from the 10G-ONU 40 (1) via the MUX unit 25, and analyzes the received PON control signal. The PON control unit 27 is based on the 10G-OL T20X based on the no-signal section of the upstream signal detected by the no-signal section detection unit 29, the PON control signal generated by itself, and the PON control signal from the 10G-ONU40 (1). Control the behavior.

 [0037] The network interface unit 28 is a communication interface connected to an external device (not shown). The network interface unit 28 inputs user data sent from the external device to the MUX unit 25 and transmits user data sent from the DMUX unit 26 to the external device.

 [0038] Next, the configuration of the 10G-ONU40 (1) will be described. 10G—ONU40 (1) is a new PON system 2X subscriber side device, WDM41, EZO converter 32, 0 / E converter 43, MUX 45, DMUX 46, PON controller 47, user interface Part 48 is provided.

 The WDM 41 is connected to the optical branch network 50 and is also connected to the EZO conversion unit 42 and the 0 / E conversion unit 43. The EZO conversion unit 42 is connected to the MUX unit 45, and the 0 / E conversion unit 43 is connected to the DMUX unit 46. The MUX unit 45 and the DMUX unit 46 are connected to the PON control unit 47 and the user interface unit 48, respectively.

 [0040] WDM41, EZO conversion unit 42, 0 / E conversion unit 43, MUX unit 45, DMUX unit 46, PON control unit 47, user interface unit 48 are WDM11, EZO conversion unit 12, OZE conversion unit 13, respectively. It has the same functions as the MUX unit 15, DMUX unit 16, PON control unit 17, and network interface unit 18.

That is, the WDM 41 multiplexes the optical signal in the upstream direction (optical multiplexing) and multiplexes the optical signal in the downstream direction (optical demultiplexing). The EZO conversion unit (λ 1 Τχ) 42 performs EZO conversion of the signal from the MUX unit 45 into a signal of wavelength λ 1 and transmits it in the upstream direction via the WDM 31. OZE converter (λ 3Rx) 43 OZE-converts the downstream signal (burst optical signal) of wavelength 3 received by WDM 41 and inputs it to DMUX section 46.

 The MUX unit 45 multiplexes the uplink PON control signal from the PON control unit 47 and the user data from the user interface unit 48 and inputs the multiplexed data to the EZO conversion unit 42. The DMUX unit 46 separates the downlink signal from the OZE conversion unit 43 into a downlink PON control signal and user data. The DMUX unit 46 inputs the separated PON control signal to the PON control unit 47 and inputs the separated user data to the user interface unit 48.

 [0043] The PON control unit 47 generates a PON control signal to be sent to the 10G-OLT 20X and inputs the PON control signal to the MUX unit 45. The PON control unit 47 receives the PON control signal sent from the 10G-OLT 20X via the DMUX unit 46, and analyzes the received PON control signal. The PON control unit 47 controls the operation of the 10G-ONU 40 (1) based on the PON control signal generated by itself and the PON control signal from the 10G-OLT20X.

 [0044] The user interface unit 48 is a communication interface connected to an external device (not shown). The user interface unit 48 inputs user data sent from the external device to the MUX unit 45 and transmits user data sent from the DMUX unit 46 to the external device. The 10G-ONU40 (2) to 10G-ONU40 (n) described later have the same configuration as the 10G-ONU40 (1).

 In the following description, 1G—ONU30 (l) to 30 (n) may be referred to as 1G—ONU30 or 1G—ONU for convenience of description. In addition, 10G-ONU40 (l) to 40 (n) may be referred to as 10G-ONU40 or 10G-ONU for convenience of explanation.

[0046] Next, changes in the configuration of the PON system 5X will be described. For example, the first PON system 5X has an existing PON system 1 including 1G—OLT10, 1G—ONU30 (1) to 1G—ONU30 (n), and an optical branch network 50. After that, 10G-OLT20X is added, and 1G-ONU30 (1) is replaced with 10G-ONU40 (1) to add a new PON system 2X to PON system 5X. After this, replace each 1G—ONU30 (2) to 1G—ON U30 (n) with 10G—ONU40 (2) to 10G—ONU40 (n) in order! The final PON system 5X consists of 10G—OLT20X and 10G—ONU40 (1) to 1G—ONU30 (n). [0047] Here, the configuration of the PON system 5X when only the existing PON system 1 exists, the configuration of the PON system 5X when the existing PON system 1 and the new PON system 2X exist, and the new PON system 2X Explain the configuration of PON system 5X when there is only one!

 FIG. 2 is a diagram showing a configuration of a PON system when only an existing PON system exists. In the PON system 5X in which only the existing PON system 1 exists, each 1G—ONU 30 (l) to 30 (n) is connected to the 1 G—OLT 10 via the optical branching network 50. Data is transmitted using wavelength λ ΐ in the upstream direction, and data is transmitted using wavelength 2 in the downstream direction.

 [0049] FIG. 3 is a diagram showing a configuration of a saddle system when an existing saddle system and a new saddle system exist. In Fig. 3, 10G-compatible OLT (10G--LT10) and 10G-ONU30 (1) are installed while sharing the optical branching network 50 between the existing ΡΟΝsystem 1 and the new ΡΟΝsystem 2Χ in ΡΟΝsystem 5Χ. Is shown.

 [0050] When existing system 2 and new system 1 exist! /, The system 5 X uses different wavelengths in the downstream direction for the existing system 1 and the new system 2 Use the same wavelength and share the band. Specifically, the existing — system 1 1G ΡΟΝ 30 (2) to 30 (η) uses wavelength λ 1 for the upstream wavelength and wavelength 2 for the downstream wavelength. On the other hand, 10G-—40 (1) of the new system 2 uses the wavelength λ1 for the upstream wavelength and uses the wavelength λ3 for the downstream wavelength.

 [0051] FIG. 4 is a diagram showing a configuration of a cocoon system when only a new cocoon system exists. Fig. 4 shows the state in which all subscriber-side devices have shifted to 10G— ΡΟ Ν (10G—ONU30 (1) to 30 (η)) in ΡΟΝSystem 5Χ! /

 [0052] In the system 5 in which only the new system 2 exists, each 10G-ONU 40 (l) to 40 (n) is connected to the 10G-OLT 20X via the optical branching network 50. Then, data is transmitted using the wavelength λ 1 in the upstream direction, and data is transmitted using the wavelength 3 in the downstream direction.

[0053] In each ΡΟΝ system 5Χ shown in Figs. 2 to 4, the uplink transmission timing is in the downlink direction. Indicated by the multiplexed PON control signal sent from That is, the 1G-PON subscriber side device is instructed to transmit in the upstream direction by the PON control signal multiplexed with the downstream signal of wavelength 2. On the other hand, the 10G-PON subscriber side device is instructed to transmit in the upstream direction by the PON control signal multiplexed with the downstream signal of wavelength 2.

 Next, the operation timing of each PON system 5X shown in FIGS. 2 and 3 will be described. FIG. 5 is a timing chart showing the operation timing of the PON system shown in FIG. In the PON system 5X, the 1G-OLT 10 periodically assigns a grant to the 1G-ONU 30 at a predetermined bandwidth update period T. Here, 1G—OLTIO (Tx) assigns all bandwidth update periods T only to 1G—ONU30 (1G region). Specifically, the PON control unit 17 of the 1G-OLT 10 assigns a bandwidth update period T to each 1 G-ONU 30 to give transmission permission (transmission permission information) to each 1 G-ONU 30. Each 1G-ONU 30 performs uplink data transmission based on the transmission permission assigned to the own device. The 1G—OLT 10 extracts user data from the signal sent from the 1G—ONU 30 and transmits it to the external device via the network interface unit 18.

 [0055] FIG. 6 is a diagram for explaining a time zone in which data transmission allocated to the existing PON system by the PON system shown in FIG. 3 is permitted. Also in the PON system 5X shown in FIG. 3, the 1G-OLT 10 periodically performs grant allocation to the 1G-ONU 30 with a predetermined bandwidth update period T. Here, 1G— OLTlO (Tx) releases part of the time within each bandwidth update period T so that the new PON system 2X can use it, and 1G— Assign to ONU30 (1G area). Each 1G-ONU 30 performs uplink data transmission only during a part of the time within the bandwidth update period T (time period during which data transmission is permitted) based on the transmission permission assigned to itself.

 FIG. 7 is a timing chart showing the operation timing of the PON system shown in FIG. 1G—OLTIO (Tx) assigns each 1 G—ONU 30 a time zone (remaining time zone) excluding the open time zone (open time zone) within the bandwidth update period T. 10G—OLT20X (T X) allocates to 10G—ONU 40 the time zone released by IG-OLTIO (TX) (part of the time within each bandwidth update period T).

[0057] Specifically, the PON control unit 17 of the 1G-OLT 10 is released within the bandwidth update cycle T. All the 1G-ONUs 30 are assigned the time zone (1G zone) excluding the time zone (10G zone). Then, an open time zone (10G region) within the bandwidth update period T is allocated to the 10G-OLT20X PON control unit 27 force 10G-ONU40.

 [0058] Of each bandwidth update period T, the ratio of the time allocated to 1G-ONU30 and the time allocated to 10G-ONU40 is, for example, the number of 1G-ONU30 connected to optical branching network 50 and that of 1 OG ONU40. Set according to the number ratio.

 [0059] 1G—ONU 30 performs uplink data transmission based on transmission permission assigned to its own device, and 10G—ONU 40 performs uplink data transmission based on transmission permission assigned to its own device. Do. The 1G—OLT 10 also extracts user data from the signal power sent from the 1G—ONU 30 and transmits it to the external device via the network interface unit 18. The 10G—OLT20X extracts user data from the signal sent from the 10G—ONU 40 and transmits it to the external device via the network interface unit 18.

 Next, detailed operation timings of the PON system 5X shown in FIG. 3 will be described.

 FIG. 8 is a timing chart showing the operation timing of the existing PON system shown in FIG. Here, as an example of the operation timing of the existing PON system 1 shown in FIG. 3, a case where 1G-OLT10 grants transmission permission to two 1G-ONU (#A) and 1G-ONU (#B) will be described. Here, 1G-ONU (#A) and 1G-ONU (#B) are any of 1G-ONU30 (2) to 30 (n).

 [0061] In the 1G-OLT10 (station side device) of the existing PON system l (lG-PON system), the PON control unit 17 has a counter inside, and the counter value (time Each 1G-ONU30 (subscriber side equipment) is synchronized by including a stamp.

[0062] The PON control unit 17 calculates the transmission timing of each 1G-ONU 30 at the band update period T (a time zone in which transmission permission is granted). As shown in FIG. 8, the PON control unit 17 sets (releases) the TN time in the bandwidth update period T in the area for the new PON system 2X. Further, the PON control unit 17 sets the time of the area (T-TN) to the area for the existing PON system 1 and allocates it to 1G-ONU. In other words, TN is assigned to the time zone for 10G-PON and the area (T-TN) is assigned to the time zone for 1G-PON. [0063] Here, the PON control unit 17 allocates the time zone from tl (0) to tl (a) to the 1G-ONU (#A) in the time of the region (T TN), and tl ( The period from a) to tl (b) is applied to 1G—ONU (#B).

 [0064] In addition, since the time zone (TN) from tl (b) to T2 (0) is an area for the new PON system 2X, the PON control unit 17 performs the processing from tl (b) to T2 (0). Specify a non-existing subscriber-side device to allow transmission, or allow any subscriber-side device to allow transmission.

 [0065] The transmission permission signal (PON control signal) from the PON control unit 17 receives the upstream signal from the time point (1G—ONU (#A)) at which reception of the upstream direction is started first every band update period T. Send to 1G—ONU (#A) and 1G—ONU (#B) just before RTT (Round Trip Time).

 FIG. 9 is a timing chart showing the operation timing of the new PON system shown in FIG. Here, as an example of the operation timing of the new PON system 2X shown in FIG. 3, a case where the 10 G-OLT 20X grants transmission permission to the 10G-ONU 40 will be described.

 [0067] The no-signal section detection unit 29 of the 10G—OLT 20X detects the no-signal section from the uplink signals transmitted from the lG—ONU (#A) and lG—ONU (#B). Here, the no-signal section detection unit 29 outputs an upstream signal in the time zone of the region (T TN) allocated to 1G—ONU (#A) and 1G—ONU (#B) in the band update period T. Detects and detects no-signal section in TN time zone when 1G-OLT10 opens.

 As shown in FIG. 9, the no-signal section detection unit 29 generates a “High” detection signal, for example, during a period in which an upstream signal is received, and receives the upstream signal. In the period, a detection signal of “Lo w” is generated. That is, the no-signal section detection unit 29 generates a waveform with a rising edge at the beginning of the band update period T when the band update period T and the 10G-PON area TN in one period are set in 1G-OLT10. A waveform with a falling edge at the beginning of region TN is generated. The no-signal section detection unit 29 inputs the generated edge waveform (no-signal section detection signal) to the PON control unit 27.

The PON control unit 27 sets the band update period T and the 10G-PON region TN based on the edge waveform from the no-signal section detection unit 29. The PON control unit 27 Based on the no-signal section detection signal received by the section detector 29, synchronization with 1G-OLT10 is established. Further, the PON control unit 27 recognizes the time of the 10G-PON area TN and transmits a transmission permission signal to the 10G-ONU before the RTT of the 10G PON area TN.

 [0070] The 10G-ONU transmits an uplink signal at a predetermined timing based on the transmission permission signal from the 10G-OLT. The uplink burst signal from the 10G-ONU is bit-synchronized by the burst synchronization unit 14 of the 10G-OLT.

 [0071] In the present embodiment, the power described for the case where the existing PON system 1 is a bidirectional lGbps 1G-PON system. The existing PON system 1 is configured by a PON system other than the 1G-PON system. Moyo! /

 [0072] Further, in the present embodiment, the power described for the case where the new PON system 2X is a bidirectional lOGbps 10G-PON system. Even if the new PON system 2X is configured by a PON system other than the 10G-PON system, Yo ...

 In the present embodiment, the transmission permission signal from the PON control unit 17 is lG-ONU (# before RTT before the first reception of uplink reception every band update period T. A), lG-ONU (# B) may be sent before the RTT. In this case, the transmission permission signal includes information indicating how long before the RTT the transmission permission signal is transmitted! (Information indicating the timing for granting transmission permission to the 1G-ONU).

 As described above, according to Embodiment 1, in the new PON system 2X, the optical branch network 50 is shared with the existing PON system 1, and the wavelength of the downlink signal is different from that of the existing PON system 1. 3 is used by autonomously detecting and using information in the time zone that is not used by the existing 1 system 1 based on the uplink signal, so that it does not affect the operation of the existing ΡΟΝ system 1 It is possible to shift to a new ΡΟΝ system 2Χ for each user terminal. Therefore, it is possible to easily replace each subscriber side device with a new ΡΟΝ system 2Χ with a simple configuration.

[0075] The ratio of the time allocated to 1G—ONU30 and the time allocated to 10G—ONU40 in each bandwidth update period Τ is the number of 1G—ONU30 and 10G ONU40 units connected to optical branching network 50. Set according to the ratio, so appropriate time according to the ratio of the number of units 1 It can be assigned to G-ONU30 and 10G-ONU40, and the existing PON system 1 and the new PON system 2X can efficiently transmit and receive signals.

 Embodiment 2.

 Next, a second embodiment of the present invention will be described with reference to FIGS. In the first embodiment, the new PON system detects the upstream time zone (no signal interval) that can be used in its own system by monitoring the upstream signal of the existing PON system 1, but in the second embodiment, By monitoring the downstream signal of the existing PON system 1 by the new PON system, the upstream time zone (no signal interval) that can be used in the local system is detected.

 FIG. 10 is a block diagram showing a configuration of the PON system according to the second embodiment. Of the constituent elements in FIG. 10, the constituent elements that achieve the same functions as those of the PON system 5X of the first embodiment shown in FIG. 1 are given the same numbers, and redundant descriptions are omitted.

 [0078] The PON system 5Y has an existing PON system 1 and a new PON system 2Y. Here, the case where the new PON system 2Y is a bidirectional lOGbps 10G-PON system, similar to the new PON system 2X of the first embodiment, will be described.

 In the present embodiment, a new PON system 2Y is added to the existing PON system 1 to form a new PON system 5Y. Here, a case will be described in which the first PON system 5Y is configured with only the existing PON system 1, and then the new PON system 2Y is added, and finally the PON system 5Y is configured with only the new PON system 2Y.

 [0080] FIG. 10 shows the configuration of the PON system 5Y in a state where the new PON system 2Y is added to the PON system 5Y configured only by the existing PON system 1! /. The new PON system 2Y is composed of 10G-OLT20Y, 10G—ONU40 (1), and optical branching network 50. The optical branch network 50 is a 2-input n-output optical branch network, and connects the new PON system 2Y and the existing PON system 1. In this embodiment, the optical fiber 51 is routed from the subscriber side of the optical branch network 50 and connected to the 10G-OLT 20Y!

[0081] Next, the configuration of the 10G-OLT20Y will be described. 10G— OLT20Y is the station equipment of the new PON system 2Y. WDM21, EZO conversion unit 22, OZE conversion unit 23, burst synchronization unit 24, MUX unit 25, DMUX unit 26, PON control unit 27, network interface In addition to the unit 28, a no-signal section detection unit 70 and an OZE conversion unit 71 are provided. The OZE conversion unit 71 is connected to the optical branch network 50 via the optical fiber 51, and the no-signal section detection unit 70 is connected to the soot conversion unit 71 and the soot control unit 27. The OZE converter (2 Rx) 71 converts the downstream signal of the wavelength λ 2 from the 1G-OLT 10 received via the optical fiber 51 and inputs it to the no-signal section detector 70.

 [0083] The no-signal section detection unit 70 analyzes the time stamp and the transmission permission information (information indicating the transmission-permitted time zone) in the transmission permission signal multiplexed on the downlink signal from the 1G-OLT10. As an analysis result, the time zone (no signal section) for upstream 10G-PON is detected. The no signal section detection unit 70 inputs the detected time zone for 10G-— of the uplink to the control unit 27.

 0084 Control unit 27 is based on the uplink 10G-PON time zone detected by no-signal section detector 70, the 70 control signal generated by itself, and the ΡΟΝ control signal of 10G- ONU40 (1) force. To control the operation of the 10G-OLT20Y.

 [0085] Here, the time zone detection process for uplink 10G-PON will be described with reference to FIG. The no-signal section detector 70 designates a non-existing subscriber side device and monitors the time zone tl (b) to t2 (0) permitted to be transmitted to the 1G-OLT 10 or all the subscriber side devices Transmission permitted time period tl (0) to tl (a), tl (a) to tl (b), t2 (0) to t2 (a), t2 (a) to t2 (b) 10G—Detects the time zone for PON.

 [0086] If the time zone tl (b) to t2 (0) that is permitted to be transmitted by specifying the subscriber side device is monitored, the monitored time zone tl (b) to t2 (0 ) Is detected as the time zone for 10G-PON.

 [0087] When monitoring the time zone permitted for transmission to all the subscriber side devices, the time zones tl (b) to t2 (0) are extracted and extracted as the time zone (area) remaining after monitoring. Time zone is detected as the time zone for 10G — PON.

Next, the operation timing of the new PON system 2Y in the PON system 5Y according to Embodiment 2 will be described with reference to FIG. As shown in FIG. 9, the no-signal section detection unit 70 generates a “High” detection signal during a period when receiving an upstream signal! /, For example, and does not receive an upstream signal. Generates a "Low" detection signal. In other words, the no-signal section detector 70 uses the 1G-OLT10 to update the bandwidth update period T and 10G-PON in one period. When the area TN is set, a waveform with a rising edge is generated at the beginning of the band update period T and a waveform with a falling edge is generated at the beginning of the area TN. The no-signal section detection unit 70 inputs the generated edge waveform (no-signal section detection signal) to the PON control unit 27.

 The PON control unit 27 sets the band update period T and the 10G-PON region TN based on the edge waveform from the no-signal section detection unit 70. Then, the PON control unit 27 synchronizes with the 1G-OLT 10 based on the no-signal section detection signal received by the no-signal section detection unit 70. Further, the time of the 10G-PON area TN is recognized, and a transmission permission signal is transmitted to 1 OG-ONU before the RTT of the 10G-PON area TN.

 [0090] The 10G-ONU 40 transmits an uplink signal at a predetermined timing based on the transmission permission signal from the 10G-OLT 20Y. The upstream signal from the 10G-ONU 40 is bit-synchronized by the burst synchronization unit 14 of the 10G OLT 20Y.

 In the present embodiment, the subscriber side force of the optical branching network 50 is also connected to the 10G-OLT 20Y by routing the optical fiber 51, and is located at a different position from the subscriber side of the optical branching network 50. The optical fiber 51 may be routed from and connected to the 10G-OLT20Y. In this case, the same effect as that obtained when the optical fiber 51 is routed from the subscriber side of the optical branching network 50 and connected to the 1 OG-OLT 20Y can be obtained.

 As described above, according to Embodiment 2, in the new PON system 2Y, the optical branch network 50 is shared with the existing PON system 1, and the wavelength of the downstream signal is different from that of the existing PON system 1 with a different wavelength λ. 3 is used by autonomously detecting and using information in the time zone that is not used by the existing ΡΟΝ system 1 based on the downlink signal, so that it does not affect the operation of the existing ΡΟΝ system 1 It is possible to shift to a new ΡΟΝ system 2Υ for each user terminal. In addition, based on the downlink signal sent from the 1G-OLT10 of the existing ΡΟΝ system 1, information on the time zone (10G ΡΟΝ time zone) not used by the existing ΡΟΝ system 1 is detected. Even when the ONU 30 is stopped, it is possible to easily shift to the new system 2.

 [0093] Embodiment 3.

Next, Embodiment 3 of the present invention will be described with reference to FIG. 11 and FIG. Fruit In the third embodiment, the timing of the existing PON system and the new PON system are synchronized by connecting a pseudo subscriber side device (pseudo ONU 60 described later) that adjusts timing to the optical branching network.

 FIG. 11 is a block diagram showing a configuration of the PON system according to the third embodiment. Among the constituent elements in FIG. 11, the constituent elements that achieve the same functions as those of the PON system 5X in the first embodiment shown in FIG. 1 are given the same numbers, and redundant descriptions are omitted.

 The PON system 5Z has an existing PON system 1, a new PON system 2Z, and a pseudo ONU (pseudo subscriber side device) 60. Here, a case will be described in which the new PON system 2Z is a bidirectional lOGbps 10G-PON system, similar to the new PON system 2X of the first embodiment.

 [0096] In the present embodiment, a new PON system 2Z is added to the existing PON system 1 to form a new PON system 5Z. Here, a case will be described in which the first PON system 5Z is configured with only the existing PON system 1, and then the new PON system 2Z is added, and finally the PON system 5Z is configured with only the new PON system 2Z.

 FIG. 11 shows the configuration of the PON system 5Z in a state where a new PON system 2Z is added to the PON system 5Z configured by the existing PON system 1 and the pseudo ONU 60! /. The new PON system 2Z consists of 10G-OLT20Z, 10G-ONU40 (1), and optical branch network 50. The optical branch network 50 is a two-input (n + 1) output optical branch network, and connects the new PON system 2Z, the existing PON system 1, and the pseudo ONU 60.

 [0098] Next, the configuration of the pseudo ONU 60 will be described. The pseudo ONU 60 includes a WDM 61, an OZE conversion unit 63a, 63b, an EZO conversion unit 62, a 10G-PON control unit (information generation unit) 67, and a 1G-PON control unit 69.

 [0099] The WDM 61 is connected to the optical branching network 50 and to the OZE conversion units 63a and 63b and the EZO conversion unit 62. The OZE conversion unit 63a is connected to the 10G-PON control unit 67, and the O / E conversion unit 63b is connected to the 1G-PON control unit 69. The 1G-PON control unit 69 is connected to the 10G-PON control unit 67, and the 10G-PON control unit 67 is connected to the EZO conversion unit 62.

[0100] WDM61, OZE converter 63a, 63b, EZO converter 62 are WDM11, O / It has the same functions as the E conversion unit 13, the EZO conversion unit 12, and the PON control unit 17. In other words, the WDM 61 multiplexes the optical signal in the upstream direction (optical multiplexing) and multiplexes the optical signal in the downstream direction (optical demultiplexing).

 [0101] The OZE converter (λ 3Rx) 63a OZE-converts the downstream signal (burst optical signal) of wavelength 3 received by the WDM 61 and inputs it to the 10G-PON controller 67. The O / E converter (2Rx) 63b OZE-converts the downstream signal (burst optical signal) of wavelength 2 received by the WDM 61 and inputs it to the 1G control unit 69. The ΕΖΟ conversion unit (λ 1 Τχ) 62 performs EZO conversion of the signal from the 10G-PON control unit 67 into an optical signal of wavelength λ 1 and transmits it in the upstream direction via the WDM 61.

 [0102] The 1G-PON control unit 69 receives the PON control signal of wavelength λ 2 sent from the 1G-OLT 10 via the OZE conversion unit 63b, and analyzes the received PON control signal. The 1G-PON control unit 69 generates a PON control signal to be sent to the 1G-OLT 10 based on the analyzed PON signal and inputs the PON control signal to the 10G-PON control unit 67.

 [0103] The 10G-PON control unit 67 receives the PON control signal of wavelength λ3 sent from the 10G-OLT 20Z via the OZE conversion unit 63a, and analyzes the received PON control signal. The 10G—PON control unit 67 generates a PON control signal to be sent to the 10G—OLT 20Z based on the analyzed PON signal. The 10G—PON control unit 67 inputs the generated PON control signal and the PON control signal from the 1G—PON control unit 69 to the EZO conversion unit 62.

 Next, the configuration of the 10G-OLT20Z will be described. 10G—OLT20Z is a new PON system 2Z station side equipment, WDM21, EZO conversion unit 22, OZE conversion unit 23, nost synchronization unit 24, MUX unit 25, DMUX unit 26, PON control unit 27, network An interface unit 28 is provided. The PON control unit 27 controls the operation of the 10G-OLT 20Z based on the PON control signal generated by itself and the PON control signal from the pseudo ONU 60.

Next, the operation procedure of the PON system 5Z will be described. The pseudo ONU 60 receives the downstream signal from the 1G-OLT 10 by the WDM 61, and inputs the OZE converted signal by the OZE converter 63b to the 1G-PON controller 69. The 1G—PON control unit 69 analyzes the PON control signal multiplexed on the downlink signal from the 1G—OLT 10, and detects an uplink 10G—PON region (no signal section). The area detection for 10G-PON is the no-signal section detection of the second embodiment. It is detected by the same processing as that for the exit 70. The 1G-PON control unit 69 inputs the detected no-signal section information to the 10G-PON control unit 67.

 In addition, the pseudo ONU 60 receives the downlink signal from the 10G-OLT 20Z by the WDM 61, and inputs the downlink signal that has been OZE-converted by the OZE conversion unit 63a to the 10G PON control unit 67. The 10 G—PON control unit 67 analyzes the PON control signal multiplexed on the downstream signal from the 10G—OLT20Z, and the upstream 1G—PON area (T—TN) and upstream 10G—PON area. Detect TN. The 10G-PON area is detected by the same processing as the no-signal section detector 70 of the second embodiment.

 Here, detailed operation timing of the PON system 5Z shown in FIG. 11 will be described.

 FIG. 12 is a timing chart showing the operation timing of the PON system shown in FIG. The PON control unit 17 of the 1G—OLT 10 sets (releases) the time of the area TN in the band update period T to the area for the new PON system 2Z. Further, the PON control unit 17 sets the time of the region (T—TN) to the region for the existing PON system 1 and assigns it to the 1G-ONU 30.

 [0108] The PON control unit 17 of the 1G-OLT 10 transmits a transmission permission signal to the 1G-ONU 30 and the pseudo-ON U 60 every band update period T. The transmission permission signal here includes information on the timing for permitting transmission to the 1G-ONU 30 and information on the time permitted for transmission (T TN). The PON control unit 17 here transmits a transmission permission signal to the 1G-ONU 30 and the pseudo-ONU 60 by lG-PON (1). The 1G-ONU 30 transmits an upstream signal of wavelength λ 1 to the 1G-OLT 10 based on the transmission permission signal from the 1G-OLT 10.

 The pseudo ONU 60 inputs the transmission permission signal from the 1G—OLT 10 to the 1G— 1 control unit 69 via the WDB 61 and the ΟΖΕ change unit 63 b. The 1G—PON control unit 69 analyzes the transmission permission signal from the 1G—OLT 10, and 1G—OLT10 starts the area that is free for the 10G—PON (time p) (10G—PON transmission permission). Start time). The 1G-PON control unit 69 of the pseudo ON U 60 inputs information on the time (time p) at which 10G-PON transmission is permitted to the 10G-PON control unit 67.

[0110] The PON control unit 27 of the 10G-OLT 20Z searches for the start position of the time zone for the 10G-PON set by the PON control unit 17 of the 1G-OLT10. First, the PON control unit 27 Provisionally set the start timing of the bandwidth update cycle T and the time zone for 10G-PON (10G area) TN. That is, the PON control unit 27 starts the start timing (time) of the 1G-PON area (area that receives 1G-PON signals) and the 10G-PON area (area that receives 10G-PON signals). And tentatively set the period. The 10G-PON area (timing) set by the PON control unit 27 is a provisional area, so the reception position (transmission position) set at this time is actually 1G-OLT10 for 10G-PON. It does not necessarily coincide with the beginning of the empty area.

 [0111] The PON control unit 27 is configured to receive the upstream signal (message) from the pseudo ONU 60 with a delay of (T-TN) from the tentatively set time zone for 1G—PON. Send transmission permission signal to NU60. That is, the PON control unit 27 grants transmission permission to the pseudo ONU 60 so that the uplink message can be received at the head (time r) of the 10G-PON area that is provisionally set.

 [0112] The 10G-PON control unit 67 of the pseudo ONU 60 receives the time (time p) at which the 10G-PON transmission is permitted and the 10-OLT20Z force specified by the 1G-PON control unit 69. The difference (rp) information from the timing is included in the upstream message (release information) and notified to the 10G-OL T20Z. At this time, the pseudo ONU 60 transmits an uplink message to 10G-OLT20Z at lOGbps.

 [0113] The upstream message from the 10G-PON control unit 67 is received by the 10G-OLT 20Z and sent to the PON control unit 27 of the 10G-OLT 20Z. The PON control unit 27 receives the time r (temporarily set time) scheduled to receive the upstream message from the pseudo ONU 60, the time q when the upstream message was actually received from the pseudo NU 60, and the upstream Based on the transmission timing difference (r—p) information included in the message, the 1G—OLT10 is free for 10G—PON (start timing) and pseudo ONU60 to 1G—OLT10 (10G— Calculate RTT up to OLT2 OZ).

[0114] The PON control unit 27 corrects the transmission timing in the transmission permission message to be transmitted to the pseudo ONU 60 based on the calculated information (area where 1G-OLT10 is free for 10G-PON, RTT). . Thereafter, the PON control unit 27 repeats transmission of a transmission permission signal to the pseudo ONU 60 until synchronization with the 1G-OLT 10 is established. And from the pseudo ONU60 Each time an uplink message is received, the 1G-OLT10 calculates an area free for 10G-PON and RTT, and corrects the transmission timing in the transmission permission message transmitted to the pseudo ONU 60.

 [0115] When the difference information in the uplink message received from the pseudo ONU 60 becomes 0, the PON control unit 27 determines that synchronization with the 1G-OLT 10 has been established. In 10G-OLT20Z, after 10G-PON area is correctly recognized, this area is used for 10G-ONU.

 Thus, according to Embodiment 3, in the new PON system 2Z, the optical branch network 50 is shared with the existing PON system 1, and the wavelength of the downstream signal is different from that of the existing PON system 1 with a different wavelength λ. 3 is used and autonomously detects and uses the information of the time zone that is not used by the existing ΡΟΝ system 1 based on the downstream signal from the pseudo ONU 60, so it does not affect the operation of the existing ΡΟΝ system 1. It is possible to migrate to a new ΡΟΝ system 2Υ on a user basis (each subscriber side terminal).

 [0117] Also, the 10G-OLT 20 determines when the uplink message is scheduled to be received from the pseudo ONU 60, the time q when the uplink message is actually received from the pseudo ONU 60, and the transmission timing included in the uplink message. The area (start timing) and RTT that are available for 10G-PON can be calculated on the basis of the difference (r-p) information, and the transition to the new PON system 2Y with a simple configuration Is possible.

 [0118] Embodiment 4.

 Next, a fourth embodiment of the present invention will be described with reference to FIGS. In the PON system 5X, in order to detect that a subscriber side device (1G-ONU30 or 10G-ONU40) is connected to the optical branching network 50, a disconory procedure is periodically performed.

 Here, the discovery procedure in each PON system 5X shown in FIG. 2 and FIG. 3 of Embodiment 1 will be described. FIG. 13 is a timing chart for explaining the discovery procedure of the PON system shown in FIG.

[0120] The 1G-OLT 10 performs the identification number identification and distance measurement of the 1G-ONU 30 connected to the optical branching network 50 by the discovery procedure. As shown in FIG. 13, in the disk scan procedure, 1G-OLT10 transmits a transmission permission signal with a window width W up no signal period to 1G-ONU30 in period P. 1G—ONU30 (subscriber equipment) Send an upstream message in the cover window. This message from 1G-ONU is received normally by 1G-OLT10.

[0121] In the new PON system 2X, the 10G-OLT 20X detects the appearance timing of the discovery window of the existing PON system 1 by the same procedure as the detection processing for the no-signal interval described in the first embodiment.

[0122] In other words, in the case of the PON system 5X shown in Fig. 3, in order to avoid the collision of upstream messages between 1G—ONU and 10G—ONU and to complete the daily procedure quickly, 1G—OL

T10 sends out a discovery message (transmission permission signal) by thinning it out within the PON system 5X. 1G—OLT 10 transmits a discovery message at the timing shown in FIG. 14, for example.

 FIG. 15 is a timing chart for explaining the discovery procedure of the PON system shown in FIG. As shown in FIG. 15, in the discovery procedure here, 1G—OL T10 transmits a transmission permission signal with an uplink no-signal section with window width W to 1G—ONU 30 in period P. The transmission permission signal transmitted from the 1G-OLT10 to the 1G-ONU30 is thinned out at a predetermined rate. In other words, the 1G-OLT 10 does not perform 1G-ONU30 discovery and provides a period.

 [0124] When the no signal interval detection unit 29 of the 10G—OLT20X detects the appearance timing of the discovery window of the existing PON system 1, the PON control unit 27 detects that the 1G—OLT10 detects 1G—ONU30 based on this appearance timing. Detects the cycle (open cycle) when no operation is performed.

 [0125] Then, the PON control unit 27 transmits, to the 10G-ONU 40, a transmission permission signal in which an uplink no-signal section having a window width W is provided based on a period in which the 1G-OLT 10 does not perform discovery of the 1G-ONU 30. In other words, the 10G-OLT10 transmits a transmission permission signal to the 1OG-ONU 40 using the timing when the transmission permission signal is interrupted by the 1G-OLT10. In other words, in the 10G-PON system, discovery of 10G-ONU 40 is performed in a cycle in which 1G-ONU 30 does not perform discovery.

[0126] 1G—ONU 30 transmits an uplink message in the discovery window. The message from the 1G-ONU 30 is normally received by the 1G-OLT10. 10G— The ONU 40 transmits an upstream message in the discovery window. This message from 10G-O NU40 is normally received by 10G-OLT10.

 [0127] It should be noted that here, the power used to detect the discovery timing of the discovery window of the existing PON system 1 by the same procedure as the detection process of the no-signal section by the 10G-OLT20X described in the first embodiment. The appearance timing of the discovery window of the existing PON system 1 may be detected by the same procedure as the detection processing of the no-signal section by the 10G-OLT20Y and 20Z described in the second and third embodiments.

 Thus, according to Embodiment 4, in the new PON system 2X, the optical branch network 50 is shared with the existing PON system 1, and the wavelength of the downstream signal is different from that of the existing PON system 1 with a different wavelength λ. 3 is used, and the discovery window of the existing ΡΟΝ system is autonomously detected based on the upstream signal and used, so that it does not affect the operation of the existing ΡΟΝ system 1 and is new on a user basis (per subscriber side terminal). It becomes possible to move to ΡΟΝSystem 2Χ

[0129] In the first embodiment, the no-signal section detection unit 29 corresponds to the detection unit described in the claims, the ΡΟΝ control unit 27 corresponds to the second band control unit, and the ΡΟΝ control unit 17 Corresponds to the first bandwidth controller. In the second embodiment, the no-signal section detection unit 70 corresponds to the detection unit described in the claims, the ΡΟΝ control unit 27 corresponds to the second band control unit, and the ΡΟΝ control unit 17 corresponds to the first band. Corresponds to the control unit. In the third embodiment, ΡΟΝ control unit 27 corresponds to the detection unit and the second band control unit described in the request range, and ΡΟΝ control unit 17 corresponds to the first band control unit.

 Industrial applicability

[0130] As described above, the ΡΟΝ system and the に connection method that are effective in the present invention are suitable for accommodating a new ΡΟ 光 in an optical access network!

Claims

The scope of the claims  [1] A PON system that accommodates a new PON that is different from the existing PON in the downlink and uplink transmission rates in the optical access network used by the existing PON. ,  The new PON transmits and receives downstream signals at a different wavelength from the existing PON, and transmits and receives upstream signals at the same wavelength as the existing PON.  The station device of the existing PON releases a predetermined time band as a new PON band and releases it when performing upstream bandwidth control of the existing PON in the upstream bandwidth of the existing PON. The time zone includes a first bandwidth control unit that performs bandwidth control so that it is not allocated to the upstream bandwidth of the existing PON,  The station apparatus of the new PON allocates an open time zone detected by the first bandwidth control unit and an open time zone detected by the detection unit to the upstream band of the new PON. A PON system comprising: a second bandwidth control unit. [2] The request is characterized in that the detection unit detects the open time zone based on an uplink signal transmitted from the existing PON subscriber-side device to the existing PON station-side device. The PON system according to Item 1. [3] The request is characterized in that the detection unit detects the open time zone based on a downstream signal transmitted from the station-side device of the existing PON to the subscriber-side device of the existing PON. The PON system according to Item 1. [4] The apparatus further includes a pseudo pseudo subscriber-side device that is connected to the optical access network on the subscriber side and transmits release information about the release time zone to the station device on the new PON.  The pseudo subscriber side device generates the release information based on a downlink signal transmitted from the station side device of the existing PON and a downlink signal transmitted from the station side device of the new PON. With a generator, The detection unit included in the new PON station side device receives the release information generated by the information generation unit, the downlink signal transmitted from the own device to the pseudo subscriber side device, and the release information at the timing received. And detecting the open time period based on The PON system according to claim 1. [5] The first bandwidth control unit includes the number of subscriber-side devices of the existing PON connected to the optical access network and the number of subscriber-side devices of the new PON connected to the optical access network. The PON system according to any one of claims 1 to 4, characterized in that an open time period is set according to the ratio of the number of units. [6] When performing a discovery in which the new PON subscriber side device is accommodated in the optical access network and entered.  The first bandwidth control unit provided in the station device of the existing PON sets a release period by releasing a predetermined disk discovery period of the disk discovery period when the existing PON is performed. And  The detection unit included in the station device of the new PON detects an open cycle when the first band control unit is open, and the second band control unit uses the open cycle detected by the detection unit. The PO according to claim 1, wherein the discovery of the new PON is performed by the V. N system.  [7] In a PON connection method for accommodating a new PON that is different from the existing PON in the downlink and uplink transmission rates in the optical access network used by the existing PON,  When the station side device of the existing PON performs bandwidth control in the upstream direction of the existing PON, a predetermined time zone of the bandwidth in the upstream direction of the existing PON is released as a new PON bandwidth and opened time A first bandwidth control step for performing bandwidth control so that the bandwidth is not allocated to the upstream bandwidth of the existing PON; and  A detecting step in which the station device of the new PON detects an open time zone in which the first bandwidth control unit is open;  A second bandwidth control step of allocating an open time zone detected by the detection unit to an upstream bandwidth of the new PON;  A first transmission step of transmitting a transmission permission signal including information on the open time zone in a downstream direction of the new PON at a different wavelength from the existing PON; A response signal to the transmission permission signal is transmitted at the same wavelength as the existing PON. A PON connection method comprising: a second transmission step of transmitting in an ON upstream direction.