JP2021019226A - Master station device, optical communication system, wavelength switching device, and wavelength switching method - Google Patents

Abstract

To reduce a delay time associated with wavelength switching by switching wavelengths faster than before in an optical communication system that adopts time-wavelength division multiplexing.SOLUTION: A master station device according to a first aspect of the present invention includes a plurality of optical termination means, optical multiplexing/demultiplexing means, and system control means. A k-th optical termination means includes a slave station device management unit that generates band mapping information corresponding to an amount of information requested by a plurality of slave station devices and designates the time and wavelength at which data is transmitted to each slave station device. The slave station device management unit includes a wavelength switching control unit that switches a wavelength used by a first slave station device to another wavelength, and changes an allocated band of the first slave station device as a band of a second slave station device. The wavelength switching control unit transmits first switching control information including another wavelength and transmittable time at the other wavelength to the first slave station device, and transmits second switching control information including transmission time of a time slot after change to the second slave station device.SELECTED DRAWING: Figure 1

Description

The present invention relates to a master station device, an optical communication system, a wavelength switching device, and a wavelength switching method, and can be applied to, for example, a wavelength switching method in a master station device in an optical access network.

International standard ITU-T G. 989.3 (see Non-Patent Document 1) discloses a wavelength switching technique in a TWDM-PON (Time and Wavelength Multiplexed Multiplexed Passive Optical Network) apparatus.

TWDM-PON is an optical access network that combines time division multiplexing technology and wavelength division multiplexing technology. The TWDM-PON has, for example, one OLT (station-side optical network unit: Optical Line Thermal) having four transmitters and receivers that perform time-division multiplexing at one wavelength with four wavelengths, and of the four wavelengths. It is composed of a plurality of ONUs (subscriber-side optical network units: Optical Network Units) having one transmitter / receiver that selectively communicates using any of the wavelengths (for example, 64). In TWDM-PON, packets are time-division-multiplexed to one wavelength, and four wavelengths are multiplexed to communicate with the ONU. That is, in TWDM-PON, packet-multiplexed transmission resources of four wavelengths are shared and used by 64 ONUs.

The transmission resource is appropriately distributed to each ONU in consideration of the communication amount and fairness, but it may be desirable to change the wavelength due to fluctuations in the communication amount and the like. With general-purpose technology, it is impossible to eliminate the physical optical wavelength change time, and even if a packet is sent while changing the wavelength, the packet cannot be received and data is lost. To do. This generally affects services, such as video and audio interruptions and longer file transfer times.

Therefore, ITU-TG. 989.3 discloses that the following techniques are used to prevent data loss.
[1] An instruction is sent from the OLT to the ONU instructing the ONU to stop transmitting the signal from the subscriber and change the wavelength.
[2] The ONU sends a message to the OLT informing the owner of the wavelength switching.
[3] When the OLT receives the wavelength switching consent from the ONU, the OLT informs the ONU to execute the wavelength switching.
[4] The ONU switches the wavelength and resynchronizes the reception.
[5] The OLT periodically transmits information on the time to be transmitted at the new wavelength to the ONU.
[6] After the ONU receives the information of [5] by the resynchronization of [4], the ONU sends a confirmation message to the OLT at the time when it should be transmitted at the new wavelength of [5].
[7] The OLT determines that the link has been reestablished by receiving the confirmation message of [6].
[8] The OLT sends the ONU information on the time when the subscriber data should be transmitted.
[9] The ONU transmits the subscriber data to the OLT at the time indicated in the time information of [8].

By performing the above operation, the wavelength is switched, so that the ONU can transmit the subscriber's data to the OLT without losing the subscriber's data.

International standard ITU-T G. 989.3, "40-Gigabit-Capable Passive Optical Networks (NG-PON2): Transmission Conference Layer Specification"

Next-generation optical access networks are required to provide services such as ultra-large capacity, ultra-low latency, and ultra-high reliability. Among them, ITU-T G. In the method shown in 989.3, even if the switching speed of the wavelength switching device is high, the switching procedure is complicated, so that the time from when the transmission of user data is stopped until the transmission becomes possible is long and delayed. There is a problem that time is long.

Therefore, for example, the video or audio of real-time communication is interrupted or stopped, the response of the remote terminal is delayed, or the file transfer time becomes long. It should be noted that these examples are phenomenological problems that may occur due to the delay related to wavelength switching in the optical access network.

Therefore, the present invention is a parent capable of improving the procedure for wavelength switching in an optical access network (system), switching wavelengths faster than before, and reducing the delay time related to wavelength switching. It is intended to provide a station device, an optical communication system, a wavelength switching device, and a wavelength switching method.

In order to solve such a problem, the first master station apparatus according to the present invention has first to second K (K is an integer of 2 or more) with M (M is an integer of 2 or more) units. The master station of the optical communication system that adopts the time wavelength division multiplexing method that assigns one of the wavelengths of the above, time-divides and multiplexes each wavelength in multiple time slots, and communicates with each time-divided and multiplexed wavelength with a multiplexed optical signal. In the device, the optical signals transmitted or received by combining the wavelengths of the K optical termination means for optical communication at any of the first to Kth wavelengths and the wavelengths from the respective optical termination means are demultiplexed. The optical combined demultiplexing means for outputting to each optical termination means and the system control means for controlling each optical termination means are provided, and optical communication is performed at a wavelength of the kth (k is an integer of 1 ≦ k ≦ K). The optical termination means of k allocates a receiving unit that receives an optical signal at the kth wavelength and a time slot to be transmitted by each slave station device according to the required information amount of a plurality of slave station devices accommodated. The slave station device management unit that generates time-divided multiplex data by time-dividing and multiplexing the band mapping information and the data of each slave station device, and the band mapping information and time-divided multiplex data generated by the slave station device management unit are the kth. It has a transmission unit that transmits by wavelength, and the slave station device management unit switches the wavelength used by the first slave station device among the plurality of slave station devices accommodated to another wavelength, and band mapping information. Has a wavelength switching control unit that changes the band assigned to the first slave station device as the band of the second slave station device, and the wavelength switching control unit is different from the first slave station device. The first switching control information including the change instruction to the wavelength of the above and the time of the transmission possible time of the uplink signal at another wavelength is transmitted, and the first slave station device is transmitted to the second slave station device. It is characterized in that the second switching control information including the transmission time of the time slot assigned to is transmitted.

The second optical communication system according to the present invention has wavelengths of the first to K (K is an integer of 2 or more) between the master station device and the slave station device of M (M is an integer of 2 or more). In an optical communication system that employs a time-wavelength division multiplexing method in which one of the above is assigned, time-division multiplexing is performed in a plurality of time slots for each wavelength, and each time-divided-multiplexed wavelength is communicated by a multiplexed optical signal, the master station device. Combines the wavelengths from each optical termination means with K optical termination means that perform optical communication at any of the first to Kth wavelengths, and transmits or demultiplexes the received optical signal. A th-th k (k is an integer in which 1 ≦ k ≦ K) is provided with optical combined demultiplexing means for outputting to each optical terminating means and a system controlling means for controlling each optical terminating means. The optical termination means of the above is a band in which a receiving unit that receives an optical signal at the kth wavelength and a time slot to be transmitted by each slave station device are assigned according to the required information amount of a plurality of slave station devices accommodated. The slave station device management unit that generates time-divided multiplex data by time-dividing and multiplexing the mapping information and the data of each slave station device, and the band mapping information and time-divided multiplex data generated by the slave station device management unit at the kth wavelength. Of the plurality of slave station devices accommodated, the slave station device management unit switches the wavelength used by the first slave station device to another wavelength, and in the band mapping information, the slave station device management unit has a transmission unit for transmitting in. It has a wavelength switching control unit that changes the band assigned to the first slave station device as the band of the second slave station device, and the wavelength switching control unit is different from the first slave station device. The first switching control information including the change instruction to the wavelength and the time when the uplink signal can be transmitted at another wavelength is transmitted, and the second slave station device is sent to the first slave station device. It is characterized in that the second switching control information including the transmission time of the assigned time slot is transmitted.

The third wavelength switching device according to the present invention has wavelengths of the first to K (K is an integer of 2 or more) between the master station device and the slave station device of M (M is an integer of 2 or more). Wavelength switching device in an optical communication system that employs a time-wavelength division multiplexing method in which one of the above is assigned, time-division multiplexing is performed in multiple time slots for each wavelength, and each time-divided-multiplexed wavelength is communicated with a multiplexed optical signal. In, the master station apparatus combines the wavelengths of the K optical termination means for optical communication at any of the first to Kth wavelengths with the wavelengths from the respective optical termination means, and transmits or receives the light. It includes an optical demultiplexing means that demultiplexes a signal and outputs it to each optical termination means, and a system control means that controls each optical termination means, at a wavelength of the kth (k is an integer in which 1 ≦ k ≦ K). The kth optical termination means for optical communication is a receiving unit that receives an optical signal at the kth wavelength and a time that each slave station device should transmit according to the required information amount of a plurality of slave station devices accommodated. The slave station device management unit that generates time-divided multiplex data by time-dividing and multiplexing the band mapping information and data of each slave station device to which slots are assigned, and the band mapping information and time-division multiplex data generated by the slave station device management unit. The slave station device management unit has a transmission unit that transmits the signal at the kth wavelength, and the slave station device management unit switches the wavelength used by the first slave station device to another wavelength among the plurality of slave station devices accommodated. It has a wavelength switching control unit that changes the band assigned to the first slave station device in the band mapping information as the band of the second slave station device, and the wavelength switching control unit becomes the first slave station device. On the other hand, the first switching control information including the change instruction to another wavelength and the time when the uplink signal can be transmitted at another wavelength is transmitted, and the first switching control information is transmitted to the second slave station device. It is characterized in that the second switching control information including the transmission time of the time slot assigned to the slave station device of is transmitted.

In the fourth wavelength switching method according to the present invention, the wavelengths of the first to K (K is an integer of 2 or more) between the master station device and the slave station device of M (M is an integer of 2 or more). In the wavelength switching method of an optical communication system that employs a time-wavelength division multiplexing method in which one of the above is assigned, time-division multiplexing is performed in a plurality of time slots for each wavelength, and each time-divided-multiplexed wavelength is communicated with a multiplexed optical signal. , The master station device combines the wavelengths from each optical termination means with K optical termination means that perform optical communication at any of the first to Kth wavelengths, and sends or receives an optical signal. A combined optical demultiplexing means for demultiplexing and outputting to each optical termination means and a system control means for controlling each optical termination means are provided, and light is emitted at a wavelength of the kth (k is an integer in which 1 ≦ k ≦ K). The kth optical termination means for communication is a receiving unit that receives an optical signal at the kth wavelength, and a time that each slave station device should transmit according to the required information amount of the plurality of slave station devices accommodated. The slave station device management unit that generates time-divided multiplex data by time-dividing and multiplexing the band mapping information and data of each slave station device to which slots are assigned, and the band mapping information and time-divided multiplex data generated by the slave station device management unit. Of the plurality of slave station devices, the slave station device management unit has a wavelength switching control unit, and the wavelength switching control unit has a transmission unit for transmitting the wavelength k. The wavelength used by the slave station device is switched to another wavelength, and the band assigned to the first slave station device in the band mapping information is changed as the band of the second slave station device to change the band of the first slave station device. The first switching control information including the change instruction to another wavelength and the time when the uplink signal can be transmitted at another wavelength is transmitted to the second slave station device. It is characterized in that the second switching control information including the transmission time of the time slot assigned to the slave station device of 1 is transmitted.

The fifth master station device according to the present invention assigns any of the first to K (K is an integer of 2 or more) wavelengths to and from the M (M is an integer of 2 or more) units. In the master station apparatus of the optical communication system adopting the time wavelength division multiplexing method in which each wavelength is time-divided and multiplexed in a plurality of time slots and each time-divided multiplex is communicated by the multiplexed optical signal, the first to first The K optical termination means that perform optical communication at any of the wavelengths of K and the wavelengths from each optical termination means are combined and transmitted, or the received optical signal is demultiplexed and sent to each optical termination means. The kth optical termination means, which includes an output optical combining means and a system control means for controlling each light group means, and performs optical communication at a wavelength of the kth (k is an integer where 1 ≦ k ≦ K), is the first. Band mapping information is generated by allocating time slots to be transmitted by each slave station device according to the required information amount of the receiver unit that receives the optical signal at the wavelength of k and the plurality of slave station devices accommodated. It has a slave station device management unit that instructs the time and wavelength at which data is transmitted to the slave station device, and a transmission unit that transmits band mapping information generated by the slave station device management unit at the kth wavelength. The device management unit has a wavelength switching control unit that switches the wavelength used by one or more slave station devices to another wavelength among the plurality of slave station devices accommodated, and one or more wavelength switching control units. It is characterized in that the first switching control information including the change instruction to another wavelength and the time when the uplink signal can be transmitted at another wavelength is transmitted to each of the slave station devices.

According to the present invention, in an optical communication system (optical access network (system)), wavelengths can be switched at a speed higher than before, and delays related to wavelength switching can be reduced. As a result, the impact on the service can be reduced.

It is a block diagram which shows the structure of the optical communication system which concerns on 1st Embodiment, and the internal structure of OLT (master station communication device) and each ONU (slave station communication device). It is explanatory drawing explaining the operation of the wavelength switching processing which concerns on 1st Embodiment (the 1). It is explanatory drawing explaining the operation of the wavelength switching processing which concerns on 1st Embodiment (the 2). It is explanatory drawing explaining the operation of the wavelength switching processing which concerns on 2nd Embodiment. It is explanatory drawing which corresponded with the basic technical proposal which concerns on embodiment of this invention, and the cause and technical problem that the delay time becomes large.

(A) Basic Concept The following describes the basic concept of the master station device, the wavelength switching device, and the wavelength switching method according to the present invention.

International standard ITU-T G. In the method shown in 989.3, the time from when the transmission of user data is stopped until the transmission becomes possible is long, and the delay time is large.

The cause of the large delay time is related to several factors, and it is considered that they are technical issues to be solved. Although it is difficult to completely separate some factors and technical issues to indicate the causes, these causes can be classified as follows (see FIG. 5).
(Item 1: Delivery confirmation and link connection confirmation) It takes time to transmit user data because the delivery confirmation of the wavelength switching instruction and the link establishment confirmation are performed by the 3-way handshake.
(Item 2: Transmission timing of wavelength change control signal) The time at which the OLT transmits the control signal related to wavelength switching to the ONU is limited. (Notified by frame header)
(Item 3: Collision avoidance procedure for uplink signal) When an ONU whose wavelength has been changed transmits an uplink signal, the OLT collects all BwMap (bandwidth allocation mapping) information in order to avoid collision with the uplink signal of another ONU. It is distributed to ONU of.
(Item 4: Availability of the destination wavelength) The wavelength cannot be changed unless the destination wavelength resource is available.

Regarding (item 1), conventionally, when the OLT continuously transmits the delivery confirmation signal related to the wavelength switching instruction and the ONU can receive the delivery confirmation signal, it is considered that the wavelength switching is completed. The exchange of these signals is confirmed by a 3-way handshake, and it takes a delay time for the ONU to start transmitting user data.

On the other hand, in the embodiment of the present invention, it is proposed that the OLT transmits the wavelength change instruction to the ONU without confirming the delivery of the wavelength switching instruction and the link establishment (Proposal 1-1). At this time, the OLT proposes to predict the ONU switching completion time and transmit the wavelength change instruction.

Further, (Proposal 1-2) In the above (Proposal 1-1), data may be lost when the wavelength change fails in the ONU. At that time, the OLT falls into a state in which the failure of the wavelength change cannot be grasped. Therefore, in the embodiment of the present invention, it is proposed that a communication method capable of dealing with the failure of the wavelength change can be adopted to reduce the influence on others. ..

Regarding (item 2), conventionally, the control signal related to the wavelength switching from the OLT to the ONU is transmitted within the time of PLOAMd (Physical Layer Operation And Management downstream) in the FS (Framing Sublayer) frame header.

Here, since the frame period is at intervals of 125 μsec, the control signal related to wavelength switching is also transmitted every frame period (125 μsec). That is, conventionally, the transmission time of the control signal related to wavelength switching is fixed, and the control signal related to wavelength switching is transmitted at intervals of 125 μsec.

However, in order to respond to services such as ultra-low delay, it is required to quickly transmit a control signal related to wavelength switching without waiting until the time of the frame cycle. In other words, when the amount of information to a certain ONU increases and it becomes necessary to increase the band of the ONU, it is required to switch the wavelength at high speed without waiting until the transmission time every 125 μs.

Therefore, in the embodiment of the present invention, it is proposed that the control signal related to (Proposal 2) wavelength switching is inserted into the FS payload or OMCC (ONU Management and Control Channel: ONU management control channel information) and transmitted. To do.

Regarding (item 3), when an ONU whose wavelength has been changed transmits an uplink signal, a method for avoiding a collision between the uplink signal and a transmission signal of another ONU is required. Conventionally, in order to avoid a collision, the OLT creates new BwMap information after changing the wavelength and distributes the new BwMap information to all ONUs.

On the other hand, in the embodiment of the present invention, it is proposed (Proposal 3-1) to distribute / update the time information that can be transmitted, such as by using BwMap having a free time periodically.

Further, in the embodiment of the present invention, it is proposed (Proposal 3-2) to instruct the OSU of the transition destination wavelength to transmit the transmission stop signal to the ONU or to transmit it at another free time.

Regarding (item 4), conventionally, even if the priority of the ONU user data using the migration destination wavelength is low, the wavelength cannot be changed unless there is a vacancy in the band, and the wavelength is changed due to the vacancy in the band. However, it cannot be transmitted until the next BwMap is distributed.

On the other hand, in the embodiment of the present invention (Proposal 4), if there is a low priority traffic or a delay-sensitive service traffic time in the transition destination wavelength band, the OSU gives the low priority traffic or delay. It is proposed that the transmission stop signal is transmitted to the ONU scheduled to transmit the traffic that is not sensitive to the signal, and is transmitted from the ONU that shifts to that time.

In addition to the above-mentioned (item 1) to (item 4), the cause of the increase in the delay time related to the wavelength change can be considered. For example, other causes of delay include (a) it takes time to change the wavelength in the wavelength variable device, (b) it takes time to synchronize bits and frames when the wavelength is changed, and (c). It is conceivable that a transmission delay due to the physical distance between the OLT and the ONU (for example, a delay time of about 100 μsec at a distance of 20 km) may occur.

However, (a) can be shortened by preparing, for example, a plurality of light sources and filters having different wavelengths and selecting them with a high-speed switch. (B) can be solved if the timing can be maintained in perfect agreement. Alternatively, it can be solved by transmitting a synchronization signal from the OSU. Regarding (c), it can be judged that it is not necessary to examine it because it is necessary to break through the speed of light due to its physical characteristics. Therefore, the countermeasures related to (a) to (c) described above will be omitted.

The present invention is an existing technique of G.I. It is possible to extend 989.3 and implement it. The present invention can be added as a speed-up option without replacing 989.3.

(B) First Embodiment The first embodiment of the master station apparatus, the optical communication system, the wavelength switching apparatus, and the wavelength switching method according to the present invention will be described in detail with reference to the drawings.

(B-1) Configuration of First Embodiment FIG. 1 shows the configuration of the optical communication system according to the first embodiment and the internal configuration of the OLT (master station communication device) and each ONU (slave station communication device). It is a block diagram which shows.

The optical communication system 5 allocates one of the first to K (K is an integer of 2 or more) wavelengths between the master station device and the slave station device of M (M is an integer of 2 or more). This is an optical communication system that employs a time-division multiplexing method in which time-division multiplexing is performed in a plurality of time slots for each wavelength and each time-division-multiplexed wavelength is communicated by a multiplexed optical signal.

FIG. 1 shows a case where the optical communication system 5 has one OLT 1, a plurality of ONUs 3 (3-1 to 3-5) (for example, 5 units in FIG. 1: M = 5), and a splitter 2. Illustrate. Further, here, a case where the optical communication system 5 is applied to a TWDM-PON system using two wavelengths (K = 2) is illustrated, but the number of wavelengths used and the number of ONUs are limited to this. However, it is generally larger than the number illustrated in FIG.

(B-1-1) OLT
The OLT 1 is connected to the core network and also to the splitter 2 through an optical fiber, and has a system control unit 11, a SW (switch) unit 12, OSU 14-1 to 14-2, and an optical duplexing filter 13. In addition, since the case of the TWDM-PON system using two wavelengths is illustrated here, two OSU14s are used, but the number of OSU14s corresponding to the number of wavelengths used will be provided.

[System control unit 11]
The system control unit 11 controls an optical communication system with each ONU 3. For example, the system control unit 11 calculates the band to be allocated to each ONU3 based on the band request from each ONU3 according to a predetermined band control method, sets / updates the bandwidth of the uplink signal of each ONU3, or sets / updates the band of the uplink signal of each ONU3. In consideration of the service, it is set to accommodate each ONU3 in either OSU14-1 or 14-2. The normal band allocation for calculating the band to be allocated to each ONU3 based on the band request from each ONU3 is performed by the BwMap calculation unit 103 described later, and the band allocation to each ONU3 is performed only when the band is allocated at high speed. It is also possible for the control unit 11 to perform this.

Then, the system control unit 11 notifies OSU14-1 and 14-2 of the information regarding the band of each ONU3. As a result, OSU14-1 and OSU14-2 can be time-division-multiplexed by allocating time slots according to the band of each ONU3. Further, the system control unit 11 notifies the SW unit 12 of the information regarding the ONU3 assigned to the OSU 14-1 and the OSU 14-2.

[SW section]
The SW unit 12 is a switch that is connected to the core network (upper network) and relays the transmission and reception of packets between the core network and the OSU 14.

The SW unit 12 transfers the packet of the user data received from the core network to either OSU14-1 or OSU14-2 according to the information notified from the system control unit 11. Further, when the SW unit 12 receives the user data received and processed by the OSU 14-1 and 14-2, the SW unit 12 transmits the user data to the core network.

[OSU]
The OSU 14 (14-1 and 14-2) is an optical termination unit that performs optical communication with each ONU 3. The OSU 14 performs optical communication at different wavelengths, allocates time slots according to the required band of each ONU3 under the control of the system control unit 11, and obtains the allocation information and user data addressed to each ONU3 from the core network. It is divided and multiplexed and transmitted.

As described above, the system control unit 11 determines whether to accommodate each ONU3 in either OSU14-1 or 14-2 in consideration of the traffic and services to and from each ONU3. Then, the control information determined by the system control unit 11 is notified to the SW unit 12 and the OSU 14, and further notified to each ONU 3 via each OSU 14. As a result, optical communication is performed between each OSU 14 and each ONU 3 accommodated in each OSU 14.

The OSU 14 with which each ONU 3 communicates is physically determined by the wavelength set in the wavelength variable transmitter 23 / wavelength variable receiver 25 in the ONU 3, and this control information is transmitted from the system control unit 11 of the OLT to the OSU-ONU. The control data is sent as a part of the information transmitted and received between the two, and the control data is further notified to the ONU control unit 21 for control.

Here, an example of accommodating each ONU3 in each OSU14 will be described.

For example, OSU14-1 and OSU14-2 use different wavelengths λ1 and λ2, respectively. OSU14-1 and OSU14-2 perform optical communication of 10 Gb / s at one wavelength in both downlink communication and uplink communication, respectively. That is, the OSU 14 and each ONU 3 housed in the OSU 14 perform optical communication at the same wavelength. Further, it is assumed that 0 to 5 ONU3s can be accommodated in one OSU14-1 and OSU14-2.

For example, assuming that the communication volume (required band) of ONU3-1 to ONU3-5 is 8Gb / s, 2Gb / s, 3Gb / s, 3Gb / s, 3Gb / s, OSU14-1 becomes ONU3-1. It is assumed that ONU3-2 is housed and OSU14-2 houses ONU3-3, ONU3-4, and ONU3-5. In this case, the total band of the wavelength λ1 of the OSU14-1 is 10 Gb / s, and the total band of the wavelength λ2 of the OSU14-2 is 9 Gb / s. ), So it can be said that it is a suitable storage example. In the case of this example, the wavelength λ2 is left over by 1 Gb / s.

If the communication volume of ONU3-1 to ONU3-5 is all 2 Gb / s, OSU14-1 may accommodate all ONU3-1 to ONU3-5. As a result, the OSU 14-2 is stopped, which can be said to be a suitable accommodation method from the viewpoint of power consumption. That is, in consideration of the required bandwidth amount and service of each ONU3, it is possible to accommodate all the ONU3s in the OSU14 of either OSU14-1 or OSU14-2, and in that case, the power consumption is reduced. Can be done.

The OSU 14 (14-1 and 14-2) has an OSU control unit 100, a reception unit 110, and a transmission unit 120.

[Receiver]
The receiving unit 110 analyzes the data from the optical receiving unit 112 that receives the optical signal from the optical duplexing filter 13 and converts the optical signal into an electric signal, and the optical receiving unit 112, and the data is user data. It has a reception frame processing unit 111 that is sometimes given to the SW unit 12 and is given to the OSU control unit 100 when the data is control data.

[OSU control unit]
The OSU control unit 100 controls the processing in the OSU 14. The OSU control unit 100 performs transmission / reception processing of control information (control data) with each ONU 3, band control processing, normal wavelength switching processing, high-speed wavelength switching processing, and the like.

Here, the normal wavelength switching process is performed by ITU-T G. It is intended for wavelength switching processing based on 989.3 standardization technology. That is, when the system control unit 11 instructs the ONU3 to switch the wavelength based on a predetermined condition, the OSU control unit 100 confirms the delivery of the wavelength switching signal with the ONU3 by a 3-way handshake. To do. Then, after the new link is established, the transmission / reception of user data is started. The transmission timing of the wavelength switching signal is the transmission time for each frame cycle, and the wavelength switching signal to ONU3 is mounted on the frame header and notified to ONU3 (see the background technology of the present specification).

On the other hand, the high-speed wavelength switching process is a process performed by the high-speed switching control unit 102, which will be described later, and is a process for performing wavelength switching at a higher speed than the normal wavelength switching process. For example, for ONU3 of the ultra-low delay service, the high-speed wavelength switching process is performed when the delay time is large in the normal wavelength switching process and the user data cannot be transmitted in the time required by the ultra-low delay service.

The OSU control unit 100 includes an ONU management control unit 101, a high-speed switching control unit 102, and a BwMap calculation unit 103.

<ONU management control unit 101>
The ONU management control unit 101 holds information about the ONU 3 accommodated in the OSU 14 based on the control information from the system control unit 11, and controls the optical communication processing with each ONU 3. The ONU management control unit 101 notifies the frame payload assembly unit 121 of the transmission unit 120 of the ONU management control unit channel information (OMCC). Here, the information about the ONU3 includes, for example, identification information for identifying each ONU3, information about the band of each ONU3, information about the type of service for optical communication with each ONU3, and the like.

<BwMap calculation unit>
The BwMap calculation unit 103 calculates BwMap information according to the request band of each ONU3 and notifies the frame header assembly unit 122 of the transmission unit 120.

<High-speed switching control unit>
The high-speed switching control unit 102 performs wavelength switching processing on the ONU3 that requires wavelength switching at high speed. At the time of high-speed switching, the high-speed switching control unit 102 notifies the frame payload assembly unit 121 of high-speed switching control information including the wavelength of the migration destination and information on the transmission time at the wavelength to the target ONU2. .. A detailed description of the processing of the high-speed switching control unit 102 will be described in the section of operation.

Here, the determination as to whether or not to perform high-speed wavelength switching is based on the control information from the receiving unit 110, taking into consideration the type of service with the ONU3 and the sudden increase in the required band of the ONU3. You may make a judgment. More specifically, the ONU3 of the ultra-low delay service may be subjected to high-speed wavelength switching when the required ultra-low delay service cannot be provided in the band allocated at that time.

[Transmitter]
The transmission unit 120 includes a frame payload assembly unit 121, a frame header assembly unit 122, a frame assembly unit 123, a physical synchronization block output unit 124, and an optical transmission unit 125.

The frame payload assembly unit 121 assembles the payload of the transmission frame based on the user data from the SW unit 12 and the ONU management control channel information (OMCC) from the ONU management control unit 101. When performing high-speed wavelength switching processing, the frame payload assembly unit 121 inserts the high-speed switching control information from the high-speed switching control unit 102 into the frame payload or the ONU management control channel information (OMCC) to transmit the payload of the transmission frame. To assemble.

The frame header assembly unit 122 assembles the header of the transmission frame. When transmitting BwMap information to all ONU3s, the frame header assembly unit 122 assembles the frame header based on the BwMap information from the BwMap calculation unit 103.

The frame assembly unit 123 assembles a transmission frame based on the payload of the transmission frame from the frame payload assembly unit 121 and the frame header from the frame header assembly unit 122.

The physical synchronization block output unit 124 gives a signal (physical synchronization block information) related to physical synchronization to the optical transmission unit 125.

The optical transmission unit 125 transmits the transmission frame from the frame assembly unit 123 and the physical synchronization block information from the physical synchronization block output unit 124 at the wavelength λ1.

Further, the optical transmission unit 125 scrambles the transmission frame from the frame assembly unit 123 and the physical synchronization block information from the physical synchronization block output unit 124 and transmits them at the wavelength λ1 when performing high-speed wavelength switching processing. It has a portion 125a.

[Optical demultiplexing filter]
The optical demultiplexing filter 13 wavelength-multiplexes optical signals (also referred to as “signal light”) from OSU14-1 and OSU14-2, and transmits a wavelength-multiplexed optical signal. As a result, the wavelength-multiplexed optical signal is transmitted to each ONU 3 via the splitter 2. When the optical signal is received via the splitter 2, the optical demultiplexing filter 13 demultiplexes the optical signal and gives the demultiplexed optical signal to OSU14-1 and OSU14-2.

(B-1-2) ONU
The ONU3 (3-1 to 3-5) communicates with the subscriber terminal and is connected to the splitter 2 through an optical fiber. The ONU 3 includes an ONU control unit 21, a transmission frame processing unit 22, a tunable transmitter 23, an optical demultiplexing filter 24, a tunable receiver 25, and a reception frame processing unit 26.

[Transmission frame processing unit]
When the transmission frame processing unit 22 receives the user data from the subscriber terminal side, it receives information about the OSU 14 to be the destination from the ONU control unit 21, assembles a transmission frame including the user data, and causes the wavelength tunable transmitter 23. give.

[Tunable transmitter]
The tunable transmitter 23 receives a transmission frame from the transmission frame processing unit 22, sets a wavelength for communication with the OSU 14 under the control of the ONU control unit 21, and transmits at that wavelength. The tunable transmitter 23 is given information on the transmission time at which the optical signal is transmitted from the ONU control unit 21, and transmits the optical signal at the transmission time.

[Optical demultiplexing filter]
The optical demultiplexing filter 24 sends an optical signal from the tunable transmitter 23 to the splitter 2 via an optical fiber. Further, when the optical demultiplexing filter 24 receives the optical signal broadcastly distributed from the splitter 2, the optical signal is given to the tunable receiver 25.

[Tunable receiver]
The wavelength tunable receiver 25 is controlled by the ONU control unit 21 to set a wavelength to be used with the OSU 14, and gives a reception frame obtained by separating the wavelength to the reception frame processing unit 26.

[Received frame processing unit]
The reception frame processing unit 26 analyzes the reception frame from the tunable receiver 25, gives the control data to the ONU control unit 21, and sends the user data to the subscriber terminal.

[ONU control unit]
The ONU control unit 21 controls the processing in the ONU3. The ONU control unit 21 receives control data from the OSU 14 through the reception frame processing unit 26, and controls optical communication with the corresponding OSU 14. The ONU control unit 21 gives the transmission frame processing unit 22 the identification information of the OSU 14 that performs optical communication. Further, the wavelength tunable transmitter 23 is provided with information regarding the wavelength to be used and the transmission time of the uplink signal. Further, the wavelength tunable receiver 25 is given a wavelength to be used.

Further, the ONU control unit 21 has a high-speed switching unit 211. When the high-speed switching control information is included in the frame payload or OMCC of the received control data, the high-speed switching unit 211 relates to the wavelength of the transition destination and the transmission time of the uplink signal included in the high-speed switching control information. Wavelength switching is performed based on the information. Specifically, the high-speed switching unit 211 gives the identification information of the migration destination OSU 14 to the transmission frame processing unit 22, and gives the wavelength tunable transmitter 23 information about the wavelength of the migration destination and the transmission time of the uplink signal. Further, the high-speed switching unit 211 gives the wavelength tunable receiver 25 the wavelength of the migration destination.

(B-2) Operation of First Embodiment Next, the operation of the wavelength switching process in the first embodiment will be described in detail with reference to the drawings.

As described above, the embodiment of the present invention does not always perform high-speed wavelength switching, but usually performs conventional wavelength switching, and if it is still not in time, performs high-speed wavelength switching processing according to the embodiment. Switch wavelengths at high speed.

In the following, the basic processing operation of the high-speed wavelength switching process of the first embodiment will be described as "high-speed wavelength switching process (No. 1)", and thereafter, after high-speed wavelength switching, collision avoidance between uplink signals is considered. The processing operation will be described as "high-speed wavelength switching processing (No. 2)".

(B-2-1) High-speed wavelength switching process (1)
FIG. 2 is an explanatory diagram illustrating the operation of the wavelength switching process according to the first embodiment.

First, how to read the explanatory diagram illustrated in FIG. 2 will be described. FIG. 2 (A) shows the flow of the downlink signal from the OSU 14 of the OLT 1 to each ONU 3, and FIG. 2 (B) shows the flow of the uplink signal from each ONU 3 to the OSU 14.

It is assumed that the OSU 14-1 performs optical communication with each of the housed ONUs 3 at a wavelength of λ1 and the OSU14-2 performs optical communication with each of the housed ONUs 3 at a wavelength of λ2.

Each OSU14 and each ONU3 assign a time slot according to the required band of each ONU3 in each OSU14 with a predetermined frame period (for example, 125 μsec) as one frame, and in the instructed time slot, for each OSU14. Upstream communication is performed from each ONU3. The downlink communication from each OSU 14 to each ONU 3 is transmitted by accommodating packets to each ONU 3 accommodated in each OSU 14 in the payload of the frame in the order of packets received from the core side. If there are restrictions such as priority and bandwidth guarantee, send according to them. Each ONU3 acquires only the information addressed to itself and discards the rest.

In FIG. 2, frames 1 to 3 are shown, and “H” arranged at the beginning of each frame indicates a frame header. Each quadrangle placed after the frame header and the number written in each quadrangle indicate the time slot (allocated band) assigned to the corresponding ONU. For example, the quadrangle described as "1" etc. , ONU3-1 and the like.

[Operation in frame 1]
In FIGS. 2A and 2B, the frame 1 shows the state of the downlink signal and the uplink signal before the wavelength switching.

It is assumed that OSU14-1 accommodates three ONU3-1, ONU3-2 and ONU3-3, and OSU14-2 accommodates two ONU3-4 and ONU3-5.

As shown in FIG. 2A, at the start time of frame 1, the OSU14-1 is set to “ONU3-1”, “ONU3-2”, “ONU3-3”, “ONU3-1”, “ONU3-2”. , "ONU3-3", "ONU3-1", and "ONU3-2" are transmitted in the order of wavelength λ1. In addition, information is sent in the same order in the upstream direction.

As described above, the downlink is basically the arrival order from the core side, but in the uplink, each OSU14 allocates a band according to the requested bandwidth from each ONU3, and the information (uplink) is assigned to the header H part for each ONU3. BwMap (information on a time when a signal may be transmitted) is accommodated and notified, and each ONU3 transmits at that time.

In OSU14-1, the BwMap calculation unit 103 allocates each time slot of ONU3-1 to ONU3-3 as illustrated in FIG. 2B according to the required band of ONU3-1 to ONU3-3. ing. Then, each ONU3 transmits a signal at the wavelength λ1 based on the assigned time slot. The signal transmitted from each ONU3 is time-division-multiplexed and reaches the OSU14.

Each ONU3 is assigned to the OSU14-2 so as to arrive alternately in the order of "ONU3-4", "ONU3-5", empty, "ONU3-4", "ONU3-5", empty, and so on. It is transmitted at the wavelength λ2 in the time slot.

That is, in OSU14-2, the BwMap calculation unit 103 has "ONU3-4", "ONU3-5", empty, and "ONU3-4" according to the required bands of ONU3-4 and ONU3-5 accommodated. , "ONU3-5", empty, ..., The time slots are assigned alternately.

Here, the amount of information (required bandwidth) from ONU3-4 and ONU3-5 addressed to OSU14-2 is assumed to be 7/10 of the payload bandwidth, and the remaining 3/10 is the free space bandwidth. And. That is, the band is evenly allocated to ONU3-4 and ONU3-5, and the BwMap calculation unit 103 allocates the band to ONU3-4 and ONU3-5 with respect to the band of frame 1. At that time, there is a predetermined length of space between the continuous time slots of "ONU3-4" and "ONU3-5" and the continuous time slots of the next "ONU3-4" and "ONU3-5". I try to have a band.

The use of this free band will be described in detail in the operation of the frame 2, but the free band is used as the band of the transition destination wavelength of the ONU3 that requires high-speed wavelength switching. In this way, by setting the BwMap information so that there is a free band in advance, when executing the high-speed wavelength switching, the high-speed wavelength switching is performed without confirming whether or not there is a free band in the migration destination wavelength. Can be executed. Further, since a plurality of free bands exist at intervals in the middle of the frame, even when high-speed wavelength switching is suddenly required, the latest free band at the migration destination wavelength is used as the band of the ONU3. Can be assigned as.

The time it takes for the downlink signals transmitted from OSU14-1 and OSU14-2 to arrive at ONU3-1 to ONU3-5 differs for each ONU3 because the distance between OSU14 and ONU3 is different. is there.

In FIG. 2, the same amount of traffic flows in opposite directions for the upstream signal and the downstream signal. This is an expression for convenience of explanation, and in reality, it is common that the up signal and the down signal have different traffic amounts and orders.

[Operation in frame 2]
In such a situation, at the time in the middle of the frame 2, the information that the system control unit 11 of the OLT 1 needs to suddenly increase the bandwidth that can be communicated between the OSU 14-1 and the ONU 3-1 (hereinafter, the following). The explanation will be made on the assumption that "emergency band increase request information") is input.

It is assumed that such emergency band increase request information is notified from the service provider side through the core network, or is notified from a control device that controls OLT1 (not shown).

Further, in the following, the ONU3-2 that is the target of wavelength switching is also referred to as a “first slave station device”, and the ONU3-1 that is required to increase the band is also referred to as a “second slave station device”.

<Operation in system control unit 11>
When the system control unit 11 is notified of the emergency band increase request information between OSU14-1 and ONU3-1, the system control unit 11 confirms the wavelength used by ONU3-1 and is optimal for ONU3-1. Calculate bandwidth allocation.

For example, the system control unit 11 has information about each ONU3 and each OSU14 accommodating each ONU3, and identifies the OSU14-1 accommodating the ONU3-1 based on such information. Then, the wavelength used by ONU3-1 is recognized. In addition, various cases can be considered with respect to the band allocated to ONU3-1. For example, the required amount (or the amount to be increased) of the information to be communicated between OSU14-1 and ONU3-1 in the emergency band increase request information. If is included, the band may be allocated to ONU3-1 according to the requested amount.

Then, the system control unit 11 considers the wavelength and band used by ONU3-1, and considers one or one of ONU3 (that is, ONU3-2 and ONU3-3) sharing the wavelength λ1 used by ONU3-1. It is determined to change the wavelength used for a plurality of ONU3s.

Here, the system control unit 11 controls to increase the allocated band of the ONU3-1 at the wavelength λ1 used by the ONU3-1. Therefore, the system control unit 11 confirms the BwMap information of the used wavelength λ1 of the ONU3-1, shifts the used wavelength of the other ONU3 sharing the used wavelength λ1 to another wavelength, and shifts the used wavelength to the shifted ONU3. The allocated band is allocated as the ONU3-1 band.

More specifically, the system control unit 11 also recognizes the BwMap information of the wavelength λ2, and sets the free band existing at the wavelength λ2 as a band newly allocated to the ONU3. In the BwMap information of the wavelength λ1 used by ONU3-1, the time slot of another ONU3 that can be reached by switching to the wavelength λ2 that appears first (in the example of FIG. 2B, the time slot of ONU3-2) is determined. , The ONU3 is targeted for high-speed wavelength switching. Therefore, in the case of this example, the wavelength λ1 used by ONU3-2 is switched to another wavelength λ2.

Then, the system control unit 11 changes the wavelength used for ONU3-2 sharing the wavelength λ1 used with ONU3-1 to the wavelength λ2, and assigns the band previously assigned to ONU3-2 at the wavelength λ1 to ONU3. The OSU control unit 100 of the OSU 14-1 is instructed to set the band to -1 minute. Further, the system control unit 11 instructs the OSU control unit 100 of the OSU 14-1 to allocate a time slot in an empty band of the wavelength λ 2 to the ONU 3-2 that changes to the wavelength λ2.

Further, the system control unit 11 also notifies the SW unit 12 that the ONU3-2 is changed to the OSU14-2. As a result, even if the user data addressed to ONU3-2 is transmitted from the core network after the high-speed wavelength switching, the user data addressed to ONU3-2 can be transferred to OSU14-2. In other words, the OSU 14-2 can perform optical communication with the ONU 3-2 at the wavelength λ 2 by using the band (time slot) newly assigned to the ONU 3-2 at the migration destination wavelength λ 2.

<Operation in OSU>
Next, in OSU 14-1, a process in which the high-speed switching control unit 102 of the OSU control unit 100 creates high-speed switching control information s to ONU3-1 and ONU3-2 and transmits the high-speed switching control information s will be described. To do.

First, in the OSU control unit 100 of the OSU 14-1, the high-speed switching control unit 102 changes the wavelength used to the ONU 3-2 to the wavelength λ2 in response to an instruction from the system control unit 11, and the time when transmission is possible. Is high-speed switching control information indicating that it is a free time between ONU3-5 to OSU14-2 and ONU3-4 to OSU14-2 (hereinafter, also referred to as "first switching control information"). Call.) Create s.

The high-speed switching control unit 102 indicates to the ONU3-1 that the time allocated to the ONU3-2 is a time that can be transmitted by the ONU3-1 (hereinafter, "second". Also called "switching control information") s is created.

In other words, the high-speed switching control unit 102 creates high-speed switching control information s including wavelength and transmission time change information for ONU3-2, and transmits time change information (transmission time change information) for ONU3-1. Create high-speed switching control information s including (addition of transmission time). In FIG. 2A, the time when the high-speed switching control information s as described above is created is referred to as a “switching signal completion time”.

The high-speed switching control unit 102 of the OSU 14-1 notifies the frame payload assembly unit 121 of the transmission unit 120 of the created high-speed switching control information s, and the frame payload assembly unit 121 transmits the high-speed switching control information s in the frame payload. Alternatively, insert it into the OMCC to assemble the frame payload.

It is assumed that the high-speed switching control information s inserted in the frame payload or OMCC is recognizable in advance between OSU14 and ONU3 by using a specific start code or the like. Therefore, the insertion position is not particularly limited as long as it is an expandable position in the frame payload or OMCC.

Here, regarding high-speed switching control information (information in which the first switching control information and the second switching control information are integrated) s as information regarding wavelength change is inserted into the frame payload or OMCC and transmitted. explain.

As described above, conventionally, the information regarding the wavelength change is inserted in the frame header and transmitted to the corresponding ONU3. That is, the frame header in which the information regarding the wavelength change is inserted is transmitted at the timing of "H" of the frame for each predetermined frame period.

However, if the information regarding the wavelength change is transmitted after waiting for the frame period, the delay time becomes large.

Therefore, by inserting the high-speed switching control information s into the frame payload or the OMCC, the information regarding the wavelength change can be transmitted to the corresponding ONU3 without waiting for the frame period. As a result, the delay time related to the wavelength change can be shortened.

After that, the frame payload in which the high-speed switching control information s is inserted in the frame payload or OMCC is read by the frame assembly unit 123 to assemble the transmission frame. That is, the destinations of the transmission frames in which the high-speed switching control information s is inserted in the frame payload or OMCC are ONU3-1 and ONU3-2. Further, the transmission frame is given to the optical transmission unit 125, is given physical synchronization block information, and is transmitted at the wavelength λ1.

Since TWDM-PON can be broadcastly transmitted to each ONU3 having the same wavelength, this function is used, but it may be instructed individually. That is, FIG. 2A shows a case where high-speed switching control information s is broadcastly transmitted to ONU3-1 and ONU3-2 whose wavelength is λ1. However, the present invention is not limited to this, and high-speed switching control information s may be individually transmitted to ONU3-1 and ONU3-2.

As described above, the transmission frame in which the high-speed switching control information s is inserted in the frame payload or OMCC is transmitted from the OSU 14-1 to the ONU 3-1 and ONU 3-2 at the wavelength λ1. Note that only one of the uplink signal and the downlink signal may have different wavelengths.

Here, the transmission timing of the high-speed switching control information s of OSU14-1 will be described.

In FIG. 2A, the switching signal completion time shows the case where the downlink signal addressed to ONU3-1 is being transmitted. Therefore, the OSU 14-1 waits until the communication addressed to the ONU 3-1 is completed after the switching signal completion time, and then transmits the high-speed switching control information s to the ONU 3-1 and 3-2. In other words, when the switching signal completion time comes in the middle of the time allotted to the ONU 3, the high-speed switching control unit 102 transmits the high-speed switching control information s after the allotted time of the ONU 3 elapses.

After that, the high-speed switching control unit 102 of OSU14-1 changes the band assigned to ONU3-2 to the band assigned to ONU3-1 at the wavelength λ1. As a result, the bandwidth for communication between OSU14-1 and ONU3-1 is increased.

Specifically, in the frame 2 of FIG. 2A, of the allocated bands of ONU3-2, the remaining band (the portion indicated by “1a”) after the transmission of the high-speed switching control information s is set to ONU3-. The band is set to 1, and the subsequent band (such as the portion indicated by "1d") is also changed to the ONU3-1 band.

Further, in OSU14-2, the free band in the BwMap information of the wavelength λ2 is changed to the band of ONU3-2. As a result, OSU14-2 newly accommodates ONU3-2 in addition to the existing ONU3-4 and ONU3-5.

It should be noted that there is a possibility that the time that can be transmitted after the change is shorter than the time length that ONU3-2 was originally supposed to transmit. In this case, ONU3-2 transmits only the amount that can be sent in the shortened time, and the rest is sent in the next and subsequent times. On the contrary, the time that can be transmitted after the change is long, and there is a possibility that the time is left over. At that time, if the queue already contains more information than originally planned, the schedule should be sent earlier.

<Operation in ONU3-2>
When the high-speed switching control information s transmitted by the OSU 14-1 is received by the ONU 3-2, in the ONU 3-2, the high-speed switching unit 211 of the ONU control unit 21 sets the wavelength to be used with respect to the wavelength tunable transmitter 23. The wavelength λ1 is changed to the wavelength λ2, and the transmission time of uplink communication is changed.

<Operation in ONU3-1>
When the high-speed switching control information s transmitted by the OSU 14-1 is received by the ONU3-1, in the ONU3-1, the high-speed switching unit 211 of the ONU control unit 21 transmits uplink communication to the wavelength tunable transmitter 23. Change the transmission time. In addition, in FIG. 2A and FIG. 2B, the time when the high-speed switching control information s is received in ONU3-1 is referred to as "transmission time additional reception time".

Then, in ONU3-1, since the transmission time of the uplink signal is added, the time of the transmission time assigned to ONU3-2 is also set as the time of the transmission time. For example, the bands “1c”, “1e”, and “1g” shown in FIG. 2B are the times of the new transmission time.

Therefore, the ONU3-1 rapidly increases the user data because its own allocated band increases, including the newly added transmission time (for example, the bands of "1c", "1e", and "1g"). The uplink signal can be transmitted at any time.

<Modification example of BwMap information of wavelength λ2>
In the example of the first embodiment described above, the BwMap information of the wavelength λ2 is "4 (ONU3-4)", "5 (ONU3-5)", empty, "4", "5", empty, "4". , "5", empty, ..., Alternately repeating the used time and the unused time.

By doing so, the waiting time until the time when there is a free band in the migration destination wavelength is shortened.

Further, as BwMap information of the wavelength λ2, such as "4", "5", "4", "5", "4", "5," 4 "," sky "," sky "," sky ". , The band of the used time may be set continuously in the frame, and then the band of the unused time may be set continuously. However, in this case, since the unused time band is set to the rear side in the frame, the BwMap information illustrated in the first embodiment is more ONU3-2 than the BwMap information of this modification. It is possible to allocate a band with a timing earlier than that of the other.

[Operation in frame 3]
In frame 3 and later, OSU14-1 and OSU14-2 insert new BwMap information optimized for the state after the wavelength switching of ONU3-2 into the frame header of the downlink frame 3 and transmit it to each ONU3. .. As a result, based on the new BwMap information, OSU14-1 performs optical communication with ONU3-1 and ONU3-3, and OSU14-2 performs optical communication with ONU3-2, ONU3-4, and ONU3-5. ..

(B-2-2) High-speed wavelength switching process (Part 2)
FIG. 3 is an explanatory diagram illustrating a preferable operation in consideration of the possibility of failure in wavelength switching in the wavelength switching process according to the first embodiment.

When the system control unit 11 issues permission to use ONU3-1 in the band used by ONU3-2, the high-speed wavelength switching process in ONU3-2 fails, and ONU3-2 transmits an uplink signal at wavelength λ1. It is conceivable that the uplink signal transmitted from the ONU3-1 at the wavelength λ1 and the uplink signal transmitted from the ONU3-2 at the wavelength λ1 collide with each other.

Therefore, in the second embodiment, the processing operation for avoiding the collision of the uplink signals transmitted at the same wavelength due to the failure of the high-speed wavelength switching process in ONU3-2 during the high-speed wavelength switching process will be described in detail.

That is, when issuing permission to use ONU3-1 in the band used by ONU3-2, the system control unit 11 gives the following instruction to the high-speed switching control unit 102 of OSU14-1. At the time when ONU3-2 is scheduled to transmit in BwMap of frame 2, the ONU3-1 is not transmitted at least once, the ONU3-2 is not transmitted at the wavelength λ1, and the wavelength switching of the ONU3-2 is performed. Make sure you are successful.

Specifically, the OSU 14-1 instructed by the system control unit 11 instructs the ONU 3-2 to switch the wavelength to the wavelength λ2 and the transmission time of the uplink signal at the wavelength λ2. Further, the OSU 14-1 allows the ONU 3-1 to transmit at the time assigned to the ONU 3-2 in addition to the transmission time notified by BwMap regarding the transmission time of the uplink signal at the wavelength λ1. However, this first permission time is set in consideration of the propagation delay between OSU14-1 and ONU3-2 until the wavelength switching and transmission time change for ONU3-2 reach ONU3-2. By setting in this way, OSU14-1 can confirm that the wavelength switching is successful in ONU3-2 because the signal does not reach from anywhere at the time. In other words, the OSU 14-1 instructs the ONU 3-1 the transmission start time of the uplink signal in consideration of the time for confirming whether the ONU 3-2 has succeeded in the high-speed wavelength switching.

Hereinafter, a detailed description will be given with reference to FIG. Since the basic processing operation is the same as that in FIG. 2, the processing operation already described with reference to FIG. 2 will be omitted below.

[Operation in frame 1]
Since it is the same as the above description using FIG. 2, detailed operation description will be omitted here.

[Operation in frame 2]
<Operation in system control unit 11>
It is assumed that the system control unit 11 is aware in advance of the propagation delay time between the OSU 14 and each ONU 3 accommodated in each OSU 3.

The system control unit 11 changes the wavelength λ2 for the ONU3-2 that shares the wavelength λ1 used by the ONU3-1, and divides the band previously allocated to the ONU3-2 at the wavelength λ1 for the ONU3-1. Instruct OSU100 of OSU14-1 to set the band. Further, the system control unit 11 instructs the OSU control unit 100 of the OSU 14-1 to allocate the free band of the wavelength λ2 to the ONU 3-2 as the band of the ONU 3-2.

At this time, the system control unit 11 obtains the transmission start time of the uplink signal of ONU3-1 based on the BwMAP information of the wavelength λ1, the BwMap information of the wavelength λ2, and the propagation delay time between OSU14 and ONU3-2. , Notifies the OSU control unit 100 of OSU14-1 of the transmission start time of the uplink signal of ONU3-1. Here, the propagation delay time between OSU14 and ONU3-2 is the propagation delay time of the physical line between OSU14 and ONU3-2. A detailed description of the transmission start time of the ONU3-1 will be described later.

Further, the system control unit 11 waits for the ONU3-2, which is the wavelength switching target, to transmit the uplink signal after receiving the high-speed switching control information s (that is, after the transmission time and the wavelength change reception time). As a result, the OSU control unit 100 of the OSU 14-1 is notified.

<Operation in OSU14-1, ONU3-1 and 3-2>
Next, in OSU 14-1, a process in which the high-speed switching control unit 102 of the OSU control unit 100 creates high-speed switching control information s to ONU3-1 and ONU3-2 and transmits the high-speed switching control information s will be described. To do.

At this time, in the OSU control unit 100 of the OSU 14-1, the high-speed switching control unit 102 can change the used wavelength to the wavelength λ2 and transmit the ONU 3-2 in response to an instruction from the system control unit 11. High-speed switching control information s indicating that the time is a free time between ONU3-5 to OSU14-2 and ONU3-4 to OSU14-2 is created.

The high-speed switching control unit 102 creates high-speed switching control information s indicating that the time allocated to ONU3-2 is a time that can be transmitted by ONU3-1 for ONU3-1. At this time, the transmittable time of ONU3-1 is scheduled after the time when the uplink signal is not transmitted from ONU3-2 in consideration of the propagation delay time based on the instruction from the system control unit 11. The time is later than the arrival time from ONU3-2 at BwMap.

Here, a method of setting the transmission start time of ONU3-1 will be described with reference to FIGS. 3 (A) and 3 (B).

The system control unit 11 grasps the BwMap information of the wavelength λ1 and the BwMap information of the wavelength λ2, the propagation delay time between OSU14 and ONU3-1, and the propagation delay time between OSU14 and ONU3-2.

First, the high-speed switching control information s is transmitted to ONU3-1 and ONU3-2, and the time when the high-speed switching control information s arrives at ONU3-1 and ONU3-2 is predicted. That is, the "transmission time additional reception time" in ONU3-1 and the "transmission time and wavelength change reception time" in ONU3-2 are predicted.

Next, from the BwMap information of the wavelength λ1 before the transmission wavelength and time of ONU3-2 are changed by the high-speed switching control information s and the propagation delay time between OSU14 and ONU3-2, the high-speed switching control information s The transmission wavelength and time scheduled by ONU3-2 before receiving the signal are the time of "A" of wavelength λ1 shown in FIG. 3 (B), that is, the front side of the two slots indicated as "empty". is expected.

Here, the time of "A" in FIG. 3B is "empty" at the wavelength λ1 when ONU3-2 succeeds in wavelength switching.

However, if ONU3-2 fails to switch wavelengths, the signal from ONU3-2 arrives instead of "empty". If this time is permitted to be transmitted to ONU3-1 as an additional transmission time by the high-speed switching control information s, and ONU3-1 is transmitting at the wavelength λ1, the signal from ONU3-1 and ONU3- Data is lost because the signal from 2 collides with it.

Here, if the time of "A" of the wavelength λ1 is "empty" as scheduled, the wavelength switching in ONU3-2 is successful, but when the signal from ONU3-2 is received, the wavelength of ONU3-2. It can be determined that the switching has failed. In this case, the high-speed switching control unit 102 instructs ONU3-1 not to transmit at the time "1g" by using the downlink signal "1d".

The high-speed switching control unit 102 refers to the BwMap information of the wavelength λ1 in FIG. 3A and the time “A” shown in FIG. 3B, and sets the time “A” in the BwMap information of the wavelength λ1. The transmission time of the ONU3-2 time slot existing after the time obtained by adding the transmission delay time between ONU3-2 and OSU14 is set as the additional transmittable time.

Specifically, the transmission time of the ONU3-1 time slot (1 g) existing after “B” shown in FIG. 3 (B) is set as the transmission start time. Since "1f" is originally the transmission time of ONU3-1, it is the time during which ONU3-1 can be transmitted before the change.

As described above, in the present embodiment, the time when "empty" is displayed in "A" and "B" of the wavelength λ1 is not notified to ONU3-1 as an additional transmission time for ONU3-1. The reason is that even if ONU3-2 fails to switch wavelengths and ONU3-2 transmits an uplink signal to OSU14-1 at the time "1b" and / or "1d" before the change instruction, ONU3 This is because it is possible to avoid a collision between the uplink signal transmitted from -1 at the wavelength λ1 and the uplink signal transmitted from ONU3-2 at the wavelength λ1.

On the contrary, from the viewpoint of OSU14-1, when the uplink signal is transmitted from ONU3-2 at the wavelength λ1, it can be grasped that the wavelength switching has failed in ONU3-2.

If the wavelength switching fails in ONU3-2, OSU14-1 instructs ONU3-1 not to communicate in the time slot time of "1g" at the time "1e", and "1g". As for the time slot time of, ONU3-2 can be used. As a result, even the time slot time of "1 g", which was originally the allocated time of ONU3-2, can be transmitted while avoiding the collision of the uplink signal.

When the wavelength switching is successful in ONU3-2, OSU14-1 does not receive anything, and OSU14-2 receives an uplink signal "2b" from ONU3-2 at the time indicated in the high-speed switching control information s. As a result, successful switching was confirmed in ONU3-2, and communication is possible after that without any problem.

On the other hand, the ONU3-1 determines that the wavelength switching in the ONU3-2 is successful based on the information "1e" of the wavelength λ1 from the OSU14-1, unless otherwise instructed by the OSU14-1, and the high-speed switching control information. As instructed by s, the transmission time is changed (added), and the uplink signal is output in the time slot of "1f", which is the original transmission time, and the time slot of "1g", which is the newly added transmission time. Send.

The method of notifying the transmission start time of ONU3-1 is not limited to the above-mentioned method. In the above-described example, the transmission start time of ONU3-1 is specified in the high-speed switching control information s. However, after notifying the ONU3-1 of the high-speed switching control information s that does not include the transmission start time of the ONU3-1 and confirming that the wavelength switching of the ONU3-2 was successful, the OSU14-1 BwMap of the wavelength λ1. At the timing of "1e" of the information, the OSU 14-1 may send the transmission permission to the ONU 3-1.

(B-3) Effect of First Embodiment As described above, according to the first embodiment, it is necessary to increase the bandwidth or transmission due to the sudden increase in user data. At that time, since the wavelength switching and transmission can be performed in a short time, the delay time related to the wavelength switching can be shortened as compared with the conventional case, and the optical communication can be performed.

Further, even if the ONU which is the wavelength switching target fails in the wavelength switching, it is possible to prevent the collision of the uplink signals transmitted at the same wavelength and avoid the data loss.

(C) Second Embodiment In the following, a second embodiment of the master station apparatus, the optical communication system, the wavelength switching apparatus, and the wavelength switching method according to the present invention will be described in detail with reference to the drawings.

(C-1) Configuration of Second Embodiment The configuration of the optical communication system of the second embodiment and the internal configuration of the OLT and the ONU are the same as those of FIG. 1 of the first embodiment. The embodiment will also be described with reference to FIG.

(C-2) Operation of the Second Embodiment FIG. 4 is an explanatory diagram illustrating an operation of the wavelength switching process according to the second embodiment.

[Operation in frame 1]
In FIGS. 4A and 4B, the frame 1 shows the state of the downlink signal and the uplink signal before the wavelength switching. Since the basic operation is the same as the above-mentioned description using FIG. 2, detailed operation description will be omitted here.

As for the BwMap information of the wavelength λ1, the OSU14-1 is "ONU3-1", "ONU3-2", "ONU3-3", "ONU3-1", "ONU3-2" as in the first embodiment. , "ONU3-3", "ONU3-1", and "ONU3-2" in that order.

On the other hand, it is assumed that the BwMap information of the wavelength λ2 is alternately assigned in the order of “ONU3-4”, “ONU3-5”, “ONU3-4”, “ONU3-5”, and so on.

The time slot time assigned in the BwMap information is reported as the time when the OLT1 permits the transmission to each ONU3. In fact, if each ONU3 has data to be transmitted to the OLT 1, each ONU3 transmits user data in the corresponding time slot time, but if there is no data to be transmitted, the corresponding time slot time. Will not be used or will send null (dummy to ignore) data.

In the second embodiment, ONU3-4 and ONU3-5 assigned in the BwMap information of wavelength λ2 are less sensitive to delay, a service having a lower priority regarding delay time than ONU3-1 to ONU3-3. It is a service, etc.

That is, from the viewpoint of low delay, it is important that the delay time of the user data of ONU3-1 to ONU3-2 is low, but the user data handled by ONU3-4 and ONU3-5 has a low delay priority of ONU3. It is premised that it is lower than each of -1 to ONU3-3, and a part of the bands of ONU3-4 to 3-5 may be reduced for the communication of ONU3-2. Even if the priority is the same, if the service is not sensitive to delay, the time may be used.

[Operation in frame 2]
In such a situation, when information that needs to increase the communication band between OSU14-1 and ONU3-1 is suddenly input to the system control unit 11 at the time in the middle of the frame 2. Is assumed.

<Operation in system control unit 11>
The system control unit 11 calculates the optimum allocation of the wavelength and band of ONU3-1 as in the first embodiment. Then, for ONU3-2 sharing the used wavelength λ1 of ONU3-1, the used wavelength is changed to wavelength λ2, and the band previously assigned to ONU3-2 at wavelength λ1 is used as the band for ONU3-1. Make a decision to allocate. Then, the system control unit 11 instructs the OSU control unit 100 of the OSU 14-1 to that effect.

Further, when the system control unit 11 switches the wavelength used by ONU3-2 to the wavelength λ2, the system control unit 11 allocates the band of ONU3-2 in addition to the bands of ONU3-4 and ONU3-5 at the wavelength λ2. Instruct the OSU control unit 100 of -2.

That is, in this embodiment, since the priority regarding the low delay of ONU3-4 and ONU3-5 is lower than that of ONU3-2, it is assigned to the previous ONU3-4 or ONU3-5. The existing band is replaced with the ONU3-2 band.

There are various methods for replacing the bands of ONU3-4 and ONU3-5, which have low priority regarding low delay, with the bands of ONU3-2, and the method is not particularly limited. In the embodiment, the band of ONU3-2 is frame 2 having a wavelength of λ2, and is “ONU3-2”, “ONU3-5”, “ONU3-4”, “ONU3-2”, “ONU3-4”, “ONU3-5”. , "ONU3-2", "ONU3-5", "ONU3-4", "ONU3-2" in this order.

<Operation in OSU14-1>
In the OSU control unit 100 of the OSU 14-1, the high-speed switching control unit 102 indicates to the ONU 3-1 that the time allocated to the ONU 3-2 is a time that can be transmitted by the ONU 3-1. Control information (second switching control information) s is created.

Further, the high-speed switching control unit 102 changes the wavelength used to the wavelength λ2 for the ONU3-2, and notifies the ONU3-2 of the time when the ONU3-2 can be transmitted in the BwMap information of the wavelength λ2. (Second switching control information) s is created.

Then, the high-speed switching control information s created by the high-speed switching control unit 102 of the OSU 14-1 is given to the frame payload assembly unit 121, and the high-speed switching control information s is inserted into the frame payload or the OMCC to insert the frame payload. Is assembled.

After that, the frame payload in which the high-speed switching control information s is inserted in the frame payload or in the OMCC is given to the frame assembly unit 123, and the frame header is added to assemble the transmission frame. Further, the transmission frame is given to the optical transmission unit 125, is given physical synchronization block information, and is transmitted at the wavelength λ1.

As described above, the transmission frame in which the high-speed switching control information s is inserted in the frame payload or OMCC is transmitted from the OSU 14-1 to the ONU 3-1 and ONU 3-2 at the wavelength λ1.

<Operation in OSU14-2>
In the OSU control unit 100 of the OSU 14-2, the high-speed switching control unit 102 transmits the BwMap information that has already been notified to ONU3-4 and ONU3-5 for a part of the transmittable time that has been permitted to be transmitted. High-speed switching control information (hereinafter, also referred to as "third switching control information") s that gives an instruction to stop is generated.

That is, since the wavelength used by ONU3-2 is changed to the wavelength λ2, a part of the band allocated to ONU3-4 and ONU3-5, which have been permitted to be transmitted, is reduced. Therefore, ONU3-4 and ONU3-5 are instructed to temporarily stop the transmission of the uplink signal (standby for the transmission of the uplink signal), and the changed band (time slot) in which a part of the allocated band is reduced. ) Is specified. The individual instructions merely notify that the bandwidth is reduced, and do not need to notify the newly changed transmission time.

Here, the reason for instructing ONU3-4 and ONU3-5 to wait for the transmission of the uplink signal at the wavelength λ2 is that when the ONU3-2 that succeeds in wavelength switching transmits the uplink signal at the wavelength λ2, the ONU3 This is to avoid a collision between the uplink signal transmitted by -2 at the wavelength λ2 and the uplink signal transmitted by ONU3-4 or ONU3-5 at the wavelength λ2.

Then, the high-speed switching control information s created by the high-speed switching control unit 102 of the OSU 14-2 is given to the frame payload assembly unit 121, and the high-speed switching control information s is inserted into the frame payload or the OMCC to insert the frame payload. Assembly is done sequentially from the beginning.

After that, the frame payload in which the high-speed switching control information s is inserted in the frame payload or in the OMCC is given to the frame assembly unit 123 from the created portion, and the frame header is added to assemble the transmission frame. Further, the transmission frame is given to the optical transmission unit 125, is given physical synchronization block information, and is transmitted at the wavelength λ2. All of this is done from the finished part, not the frame perforation or after the frame is finished.

As described above, the transmission frame in which the high-speed switching control information s is inserted in the frame payload or in the OMCC is transmitted from the OSU 14-2 to the ONU 3-4 and ONU 3-5 at the wavelength λ2.

<Operation in ONU3-1 and ONU3-2>
Since the basic operation is the same as the above-mentioned description using FIG. 2, detailed operation description will be omitted here.

<Operation in ONU3-4 and ONU3-5>
When the high-speed switching control information s transmitted by the OSU 14-2 is received by the ONU3-4 and ONU3-5, in the ONU3-4 and ONU3-5, the high-speed switching unit 211 of the ONU control unit 21 uses a tunable transmitter. For 23, the time of the transmittable time of uplink communication is changed. In FIGS. 4A and 4B, the time when the high-speed switching control information s is received in ONU3-4 and ONU3-5 is referred to as "reception time for reducing transmission time".

Here, as shown in FIG. 4B, ONU3-4 and ONU3-5 temporarily wait for the transmission of the uplink signal (wait for transmission of the uplink signal) after receiving the high-speed switching control information s, and then wait for the transmission of the uplink signal. , The uplink signal is transmitted at the time of the changed transmission time specified in the high-speed switching control information s, or at the next transmission time specified by BwMap if the changed transmission time is not set. By doing so, the BwMap information of the wavelength λ2 is updated including the band of ONU3-2 which newly uses the wavelength λ2, and the ONU3-4, ONU3-5, and ONU3-2 have the wavelength λ2. Optical communication using is possible.

The ONU3-4 and ONU3-5 wait (stop) the transmission of the uplink signal only for the time until the information transmitted by the ONU3-2 arrives at the OSU14-2. At this time, in ONU3-4 and ONU3-5, the data to be transmitted is kept in a queue, and the data is transmitted after the next transmittable time.

[Operation in frame 3]
The same band allocation method as in frame 2 is performed for the time after frame 3 on the premise that the uplink signal and the downlink signal are transmitted with the same BwMap information as in frame 2.

OSU14-1 and OSU14-2 insert new optimized BwMap information into the frame header of the downlink frame 3 and transmit it to each ONU3. As a result, based on the new BwMap information, OSU14-1 performs optical communication with ONU3-1 and ONU3-3, and OSU14-2 performs optical communication with ONU3-2, ONU3-4, and ONU3-5. ..

As described above, also in the second embodiment, the ONU3-2 changes the wavelength used to the wavelength λ2, and the ONU3-1 can perform optical communication during the transmittable time assigned to the ONU3-2 at the wavelength λ1. Become.

<Remarks>
In the above-mentioned operation, the first important point regarding the transmission start time is that the transmission start time of ONU3-2 is notified by designating the time when ONU3-4 and ONU3-5 do not transmit at the wavelength λ2. When issuing permission to use ONU3-1 in the band used by ONU3-2 in the BwMap information of wavelength λ1, the transmission start time of ONU3-1 notifies ONU3-2 of the wavelength change. Therefore, it is after the time when the transmission of the uplink signal from ONU3-2 is stopped. This is to prevent collision of the uplink signal as described in the first embodiment, and the ONU3-2 whose wavelength is changed is the uplink signal at the wavelength λ1 during the propagation delay time between the OSU14 and the ONU3-2. It means that it is after the time when the processing time until the OSU14-1 grasps that the above is not transmitted is added.

The second important point regarding the transmission start time is that the ONU3-2 has a wavelength of λ2 and the transmission start time is the time when the OSU14-2 can transmit the high-speed switching control information s, and the ONU3-4 and ONU3-5 The time is set to be after the time when the propagation delay time is added and the processing time until the ONU3-4 and ONU3-5 understand that the uplink signal should not be transmitted is added. This is also to avoid collision of the uplink signal transmitted at the wavelength λ2.

(C-3) Effect of Second Embodiment As described above, according to the second embodiment, when a band having a low priority of low delay is assigned to the migration destination wavelength, it is assigned to the migration destination wavelength. Part or all of the band is replaced with the band of the ONU to be wavelength-switched. As a result, when it becomes necessary to increase the band due to an increase in user data in a hurry, wavelength switching becomes possible at high speed, so that the delay time related to wavelength switching is shortened compared to the conventional case, and optical communication is performed. be able to.

5 ... Optical communication system, 2 ... Splitter,
1 ... OLT (master station device), 11 ... system control unit, 12 ... SW (switch) unit, 14 (14-1 to 14-n) ... OSU, 13 ... optical network unit filter, 100 ... OSU control unit, 101 ... ONU management control unit, 102 ... high-speed switching control unit, 103 ... BwMap calculation unit, 110 ... reception unit, 111 ... reception frame processing unit, 112 ... optical reception unit, 120 ... transmission unit, 121 ... frame payload assembly unit, 122 ... Frame header assembly unit, 123 ... Frame assembly unit, 124 ... Physical synchronization block output unit, 126 ... Optical transmission unit, 1265a ... Scramble unit,
3 (3-1 to 3-5) ... ONU (slave station device), 21 ... ONU control unit, 211 ... high-speed switching unit, 22 ... transmission frame processing unit, 23 ... tunable transmitter, 24 ... optical combined demultiplexing filter , 25 ... Tunable wavelength receiver, 26 ... Received frame processing unit.

The third wavelength switching device according to the present invention assigns any of the first to K (K is an integer of 2 or more) wavelengths to and from the slave station device of M (M is an integer of 2 or more). In the wavelength switching device in the optical communication system adopting the time wavelength division multiplexing method in which each wavelength is time-divided and multiplexed in a plurality of time slots and each time-divided and multiplexed wavelength is communicated by the multiplexed optical signal, the first 1st The K optical termination means for optical communication at any of the Kth wavelengths and the wavelengths from each optical termination means are combined and transmitted, or the received optical signal is demultiplexed and each optical termination means is used. The kth optical termination means, which is provided with an optical combined demultiplexing means for outputting to and a system control means for controlling each optical termination means, and which performs optical communication at a wavelength of the kth (k is an integer where 1 ≦ k ≦ K) Band mapping information and each child to which a receiving unit that receives an optical signal at the kth wavelength and a time slot to be transmitted by each slave station device are assigned according to the required information amount of a plurality of slave station devices accommodated. A slave station device management unit that generates time-divided multiplex data by time-dividing the data of the station device, and a transmission unit that transmits the band mapping information and time-divided multiplex data generated by the slave station device management unit at the kth wavelength. Of the plurality of slave station devices accommodated, the slave station device management unit switches the wavelength used by the first slave station device to another wavelength, and the first slave station in the band mapping information. It has a wavelength switching control unit that changes the band assigned to the device as the band of the second slave station device, and the wavelength switching control unit instructs the first slave station device to change to another wavelength. The time slot assigned to the first slave station device for the second slave station device by transmitting the first switching control information including the time of the transmittable time of the uplink signal at another wavelength. It is characterized in that the second switching control information including the transmission time of is transmitted.

The fifth master station device according to the present invention assigns any of the first to K (K is an integer of 2 or more) wavelengths to and from the M (M is an integer of 2 or more) units. In the master station apparatus of the optical communication system adopting the time wavelength division multiplexing method in which each wavelength is time-divided and multiplexed in a plurality of time slots and each time-divided multiplex is communicated by the multiplexed optical signal, the first to first The K optical termination means that perform optical communication at any of the wavelengths of K and the wavelengths from each optical termination means are combined and transmitted, or the received optical signal is demultiplexed and sent to each optical termination means. The kth optical termination means, which includes an output optical combining means and a system control means for controlling each optical termination means, and performs optical communication at a wavelength of the kth (k is an integer where 1 ≦ k ≦ K), is the first optical ending means. Band mapping information is generated by allocating time slots to be transmitted by each slave station device according to the required information amount of the receiver unit that receives the optical signal at the wavelength of k and the plurality of slave station devices accommodated. has a slave station apparatus management unit for instructing the time and wavelength for transmitting data to the slave station apparatuses, and a transmitting unit that transmits bandwidth mapping information generated by the slave station apparatus management unit at the wavelength of the k, remote station The device management unit generates the band mapping information in which a free band exists between the time slots assigned to each slave station device, and the slave station device management unit generates one of the plurality of slave station devices accommodated. It has a wavelength switching control unit that switches the wavelength used by one or more slave station devices to another wavelength, and the wavelength switching control unit exists with band mapping information of different wavelengths for each of the one or more slave station devices. First switching control information including an instruction to change to another wavelength and a time when an uplink signal can be transmitted, which is the start time of the free band of another wavelength , with the free band to be assigned as the allocated band of the other wavelength. It is characterized by transmitting.

Claims (12)

One of the first to K (K is an integer of 2 or more) wavelengths are assigned to and from M (M is an integer of 2 or more) units, and time division multiplexing is performed in a plurality of time slots for each wavelength. In the master station device of the optical communication system that employs the time-wavelength division multiplexing method in which each time-division-multiplexed wavelength is communicated by a multiplexed optical signal.
K optical terminal means for optical communication at any of the first to Kth wavelengths, and
Optical network unit demultiplexing means that combines the wavelengths from each optical network unit and sends it out, or demultiplexes the received optical signal and outputs it to each optical network unit.
A system control means for controlling each of the optical termination means is provided.
The k-th optical termination means for optical communication at the k-th (k is an integer in which 1 ≦ k ≦ K) wavelength is
A receiver that receives an optical signal at the kth wavelength,
The time and time when band mapping information is generated by allocating the time slot to be transmitted by each slave station device according to the requested information amount of the plurality of slave station devices accommodated and the data is transmitted to each slave station device. The slave station device management unit that specifies the wavelength and
It has a transmission unit that transmits the band mapping information generated by the slave station device management unit at the kth wavelength.
Among the plurality of slave station devices accommodated by the slave station device management unit, the wavelength used by the first slave station device is switched to another wavelength, and the first slave station device in the band mapping information. It has a wavelength switching control unit that changes the band assigned to the second slave station device as the band of the second slave station device.
The wavelength switching control unit
The first switching control information including the change instruction to the other wavelength and the time when the uplink signal can be transmitted at the other wavelength is transmitted to the first slave station device.
A master station apparatus characterized in that a second switching control information including a transmission time of a time slot assigned to the first slave station apparatus is transmitted to the second slave station apparatus. The wavelength switching control unit
The first switching control information includes the fact that the first slave station device is instructed to temporarily wait for transmission of the uplink signal after receiving the first switching control information.
With respect to the second slave station device, the time after the time when the first slave station device is capable of transmitting at the other wavelength and after the time when the transmission arrival of the uplink signal is completed is newly added. The master station apparatus according to claim 1, wherein the transmission start time of the time slot added to the above is included in the second switching control information. The wavelength switching control unit adds the propagation delay time between the first slave station device and the optical termination means to the end time of the transmittable time of the first slave station device at the other wavelength. The master station apparatus according to claim 2, wherein the transmission time of the time slot after the time is set as the transmission start time. The wavelength switching control unit supplies high-speed switching control information including the first switching control information and the second switching control information to both the first slave station device and the second slave station device. The master station apparatus according to claim 2 or 3, characterized in that transmission is performed. The wavelength switching control unit of the other optical termination means that performs optical communication at the other wavelength, which is the transition destination wavelength of the first slave station device, is
A time slot is assigned according to the amount of information requested by the first slave station device, the band mapping information at the other wavelength is changed, and the time slot is temporarily changed with respect to the other slave station device. The master station apparatus according to any one of claims 1 to 4, wherein the transmission standby of the uplink signal is made to wait, and the third switching control information including the transmission time of the changed time slot is transmitted. The wavelength switching control unit of the other optical termination means
With respect to the other slave station device, the time after the time when the first slave station device is capable of transmitting at the other wavelength and after the time when the transmission arrival of the uplink signal is completed is changed. The master station apparatus according to claim 5, wherein the transmission time of the later time slot is included in the third switching control information. 5. A claim, wherein each slave station device housed in the other optical network unit has a relatively low priority for low delay or a service that is relatively insensitive to delay. Or the master station apparatus according to 6. The first to third switching control information created by the wavelength switching control unit is inserted into the frame payload of the transmission frame or the slave station management control channel and transmitted to the corresponding slave station device. The master station apparatus according to any one of claims 2 to 7. One of the first to second K (K is an integer of 2 or more) wavelengths are assigned between the master station device and the slave station devices of M (M is an integer of 2 or more), and each wavelength has a plurality of times. In an optical communication system that employs a time-wavelength division multiplexing method in which time-division multiplexing is performed in slots and each wavelength divided and multiplexed is communicated by a multiplexed optical signal.
The master station device
K optical terminal means for optical communication at any of the first to Kth wavelengths, and
Optical network unit demultiplexing means that combines the wavelengths from each optical network unit and sends it out, or demultiplexes the received optical signal and outputs it to each optical network unit.
A system control means for controlling each of the optical termination means is provided.
The k-th optical termination means for optical communication at the k-th (k is an integer in which 1 ≦ k ≦ K) wavelength is
A receiver that receives an optical signal at the kth wavelength,
The time and time when band mapping information is generated by allocating the time slot to be transmitted by each slave station device according to the requested information amount of the plurality of slave station devices accommodated and the data is transmitted to each slave station device. The slave station device management unit that specifies the wavelength and
It has a transmission unit that transmits the band mapping information generated by the slave station device management unit at the kth wavelength.
Among the plurality of slave station devices accommodated by the slave station device management unit, the wavelength used by the first slave station device is switched to another wavelength, and the first slave station device in the band mapping information. It has a wavelength switching control unit that changes the band assigned to the second slave station device as the band of the second slave station device.
The wavelength switching control unit
The first switching control information including the change instruction to the other wavelength and the time when the uplink signal can be transmitted at the other wavelength is transmitted to the first slave station device.
An optical communication system characterized in that a second switching control information including a transmission time of a time slot assigned to the first slave station device is transmitted to the second slave station device. One of the first to second K (K is an integer of 2 or more) wavelengths are assigned between the master station device and the slave station devices of M (M is an integer of 2 or more), and a plurality of times are assigned to each wavelength. In a wavelength switching device in an optical communication system that employs a time-division multiplexing method in which time-division multiplexing is performed in slots and each wavelength divided and multiplexed is communicated by a multiplexed optical signal.
The master station device
K optical terminal means for optical communication at any of the first to Kth wavelengths, and
Optical network unit demultiplexing means that combines the wavelengths from each optical network unit and sends it out, or demultiplexes the received optical signal and outputs it to each optical network unit.
A system control means for controlling each of the optical termination means is provided.
The k-th optical termination means for optical communication at the k-th (k is an integer in which 1 ≦ k ≦ K) wavelength is
A receiver that receives an optical signal at the kth wavelength,
The time and time when band mapping information is generated by allocating the time slot to be transmitted by each slave station device according to the requested information amount of the plurality of slave station devices accommodated and the data is transmitted to each slave station device. The slave station device management unit that specifies the wavelength and
It has a transmission unit that transmits the band mapping information and the time division multiplexing data generated by the slave station device management unit at the kth wavelength.
Among the plurality of slave station devices accommodated by the slave station device management unit, the wavelength used by the first slave station device is switched to another wavelength, and the first slave station device in the band mapping information. It has a wavelength switching control unit that changes the band assigned to the second slave station device as the band of the second slave station device.
The wavelength switching control unit
The first switching control information including the change instruction to the other wavelength and the time when the uplink signal can be transmitted at the other wavelength is transmitted to the first slave station device.
A wavelength switching device characterized in that a second switching control information including a transmission time of a time slot assigned to the first slave station device is transmitted to the second slave station device. One of the first to second K (K is an integer of 2 or more) wavelengths are assigned between the master station device and the slave station devices of M (M is an integer of 2 or more), and a plurality of times are assigned to each wavelength. In the wavelength switching method of an optical communication system that employs a time-division multiplexing method in which time-division multiplexing is performed in slots and each wavelength divided and multiplexed is communicated by a multiplexed optical signal.
The master station device
K optical terminal means for optical communication at any of the first to Kth wavelengths, and
Optical network unit demultiplexing means that combines the wavelengths from each optical network unit and sends it out, or demultiplexes the received optical signal and outputs it to each optical network unit.
A system control means for controlling each of the optical termination means is provided.
The k-th optical termination means for optical communication at the k-th (k is an integer in which 1 ≦ k ≦ K) wavelength is
A receiver that receives an optical signal at the kth wavelength,
The time and time when band mapping information is generated by allocating the time slot to be transmitted by each slave station device according to the requested information amount of the plurality of slave station devices accommodated and the data is transmitted to each slave station device. The slave station device management unit that specifies the wavelength and
It has a transmission unit that transmits the band mapping information generated by the slave station device management unit at the kth wavelength.
The slave station device management unit has a wavelength switching control unit.
The wavelength switching control unit
Among the plurality of accommodated slave station devices, the wavelength used by the first slave station device is switched to another wavelength, and the band assigned to the first slave station device in the band mapping information is assigned to the first slave station device. Change as the band of the slave station device of 2
The first switching control information including the change instruction to the other wavelength and the time when the uplink signal can be transmitted at the other wavelength is transmitted to the first slave station device.
A wavelength switching method comprising transmitting second switching control information including a transmission time of a time slot assigned to the first slave station device to the second slave station device. One of the first to K (K is an integer of 2 or more) wavelengths are assigned to and from M (M is an integer of 2 or more) units, and time division multiplexing is performed in a plurality of time slots for each wavelength. In the master station device of the optical communication system that employs the time-wavelength division multiplexing method in which each time-division-multiplexed wavelength is communicated by a multiplexed optical signal.
K optical terminal means for optical communication at any of the first to Kth wavelengths, and
An optical combining means that combines the wavelengths from the respective optical termination means and transmits the wavelength, or demultiplexes the received optical signal and outputs the wavelength to each of the optical termination means.
A system control means for controlling each of the light group means is provided.
The k-th optical termination means for optical communication at the k-th (k is an integer in which 1 ≦ k ≦ K) wavelength is
A receiver that receives an optical signal at the kth wavelength,
The time and time when band mapping information is generated by allocating the time slot to be transmitted by each slave station device according to the requested information amount of the plurality of slave station devices accommodated and the data is transmitted to each slave station device. The slave station device management unit that specifies the wavelength and
It has a transmission unit that transmits the band mapping information generated by the slave station device management unit at the kth wavelength.
The slave station device management unit has a wavelength switching control unit that switches the wavelength used by one or more slave station devices to another wavelength among the plurality of slave station devices accommodated.
The wavelength switching control unit
To transmit the first switching control information including the change instruction to the different wavelength and the time when the uplink signal can be transmitted at the different wavelength to each of the one or more slave station devices. A master station device characterized by.

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