JP4372058B2 - PON optical transmission system - Google Patents

Description

  The present invention relates to a PON optical transmission system, and more particularly to a PON optical transmission system suitable for connecting a plurality of subscriber devices by branching a plurality of optical fibers in a receiving station.

  As one of the Internet providing methods, there is a PON (Passive Optical Network) method in which an optical network is constructed by branching one optical fiber into a plurality of pieces in order to effectively use an optical fiber.

  For the optical transmission system 110 in the conventional PON system, the optical fiber is wired from two station devices each having two optical interfaces having 1 to 32 channel channels to eight 16-branch splitters installed on the line. An example in which 128 subscriber units can be connected will be described with reference to FIG.

  The first and second station devices 111 and 112 and the first to fourth two-branch splitters 121 to 124 are installed as equipment in the communication station, and the first to eighth 16-branch splitters 131 to 138 are installed. Install on the track.

  One optical fiber to which 1 to 32 ch of one optical interface (first optical interface) of the first station apparatus 111 is allocated is assigned to the first two-branch splitter 121 by the first allocated channel range. The optical fiber is branched into one optical fiber having 1 to 16 channels of the optical interface and one optical fiber having an assigned channel range of 17 to 32 channels of the first optical interface. Then, one optical fiber whose assigned channel range is 1 to 16 ch of the first optical interface is branched from the first core wire to the 16th core wire by the first 16 branch splitter 131. Further, one optical fiber whose assigned channel range is 17 to 32 ch of the first optical interface is branched from the first core wire to the 16th core wire by the second 16-branch splitter 132.

  One optical fiber to which channels 1 to 32ch of the other optical interface (second optical interface) of the first station apparatus 111 are assigned is assigned to the second two-branch splitter 122 so that the assigned channel range is second. The optical fiber branches into one optical fiber that is 1 to 16 ch of the optical interface and one optical fiber that has an assigned channel range of 17 to 32 ch of the second optical interface. Then, one optical fiber whose assigned channel range is 1 to 16 ch of the second optical interface is branched from the first core wire to the 16th core wire by the third 16-branch splitter 133. In addition, one optical fiber whose assigned channel range is 17 to 32 ch of the second optical interface is branched from the first core line to the 16th core line by the fourth 16-branch splitter 134.

  One optical fiber to which 1 to 32 ch of one optical interface (third optical interface) of the second station apparatus 112 is assigned is assigned to an assigned channel range of 1 to 16 ch by the third two-branch splitter 123. And one optical fiber having an assigned channel range of 17 to 32 ch. Then, one optical fiber whose assigned channel range is 1 to 16 ch of the third optical interface is branched from the first core wire to the 16th core wire by the fifth 16 branch splitter 135. In addition, one optical fiber whose assigned channel range is 17 to 32 ch of the third optical interface is branched from the first core wire to the 16th core wire by the sixth 16-branch splitter 136.

  One optical fiber to which channels 1 to 32 of the other optical interface (fourth optical interface) of the second station apparatus 112 are allocated is assigned to an allocated channel range of 1 to 16 by the fourth two-branch splitter 124. And one optical fiber having an assigned channel range of 17 to 32 ch. Then, one optical fiber whose assigned channel range is 1 to 16 ch of the fourth optical interface is branched from the first core wire to the 16th core wire by the seventh 16-branch splitter 137. In addition, one optical fiber whose assigned channel range is 17 to 32 ch of the fourth optical interface is branched from the first core wire to the 16th core wire by the eighth 16-branch splitter 138.

  In this way, in the conventional optical transmission system 110 using the PON system, as shown in FIG. 10, the channel allocation device 115 is used, and the first optical interface 1 to 32 ch and the second optical interface 1 to 32 ch are used. , 1 to 32 ch of the third optical interface and 1 to 32 ch of the fourth optical interface are all connected to the subscriber unit connected to the cores branched from the first to eighth 16-branch splitters 131 to 138. Each is assigned.

  That is, in a conventional PON optical transmission system (hereinafter referred to as “PON optical transmission system”), only N branching splitters are provided so that N × M subscriber units can be connected. From the beginning of constructing an optical network so that a plurality of station devices can be assigned to N × M subscriber devices from a plurality of station devices, a plurality of station devices are connected to a communication station. It is installed as a facility in the building.

In Patent Document 1 below, a device-side optical fiber optically connected to a transmission device is accommodated in a coupler so that an optical fiber can be efficiently and economically added in response to an increase in the number of users. The optical fiber branches into a plurality of external optical fibers via a station optical coupler housed in the section, and each of the optical fibers is routed to a distribution optical coupler housed in an optical junction box. In an optical transmission system in which a plurality of distribution optical fibers are branched by a distribution optical coupler and each of these distribution optical fibers is routed to a terminal, a plurality of types of station-side optical couplers having different branch numbers are provided in the coupler housing. An optical wiring method in which the number of distribution optical couplers and the number of branches that are optically connected to one transmission device via a station-side optical coupler are different depending on the number of branches of each station-side optical coupler. It is disclosed.
JP 2005-17519 A

  However, in the above-described conventional PON optical transmission system, from the beginning of the construction of an optical network, a plurality of station devices are used as equipment in a communication station so that channels can be allocated to all N × M subscriber devices. Because of the installation, there was a problem that the initial investment of the equipment in the communication station building was large.

  An object of the present invention is to provide a PON optical transmission system that can significantly reduce the initial investment of equipment in a communication station building and the space for accommodating communication equipment.

The PON optical transmission system of the present invention is provided with M N-branch splitters (31 to 38) on the line so that N × M subscriber units can be connected, and for a plurality of stations. a from the device (11, 12) a PON system optical transmission system for use in an optical network of PON type constructed by allocating the channel one by one to the N × M pieces of subscriber equipment, said PON system The number of stations necessary for allocating channels one by one to only ( N × M) / (multiple of 2) subscriber devices that were installed at the beginning of the construction of the optical network. apparatus for the (11), wherein disposed initially to construct an optical network of PON type as the communication station building facilities, and the central office equipment required number (11) of the M N branch scan At least one L-branch splitter (21, 22) for connecting all of the liters (31-38) via an optical fiber, and as an equipment in the communication station at the beginning of constructing the PON optical network At the beginning of constructing the installed PON optical network, the necessary number of station devices (11) are connected to each of the N N branch splitters of the M N branch splitters (31 to 38). A channel assignment device (15) for assigning channels to at least one subscriber device one by one and assigning channels to only a total of (N × M) / (multiple of 2) subscriber devices; When the channel allocation device (15) initially constructs the PON optical network, one of the necessary number of station devices (11). From the station apparatus, a predetermined number of consecutive y channels out of the x channels are assigned to the subscriber apparatus connected to one of the M N branch splitters (31 to 38). One at a time according to the allocation direction, and the remaining one of the x channels is transmitted to a subscriber unit connected to the other one of the M N branch splitters (31 to 38). Of the (x−y) channels, z consecutive channels (z is less than or equal to xy) are allocated one by one in accordance with an allocation direction opposite to the predetermined allocation direction, and the PON optical network is allocated. At the beginning of construction, only the necessary number of station devices (11) are installed as equipment in the communication station, and after the construction of the PON optical network, the number of subscribers increases. The number of subscriber devices connected to at least one N-branch splitter among the N-branch splitters (31 to 38) increases, and a channel is allocated only by the necessary number of station devices (11). If it becomes impossible, the other station device (12) among the plurality of station devices (11, 12) is newly installed as the equipment in the communication station, thereby reducing the number of subscribers. It is characterized in that the number of station devices to be installed as equipment in a communication station at the beginning of constructing a PON optical network is reduced .
Here, the number of subscribers increases after the channel allocation device (15) constructs the PON optical network, and the number of subscriber devices connected to the one N-branch splitter increases. When the channel cannot be assigned to the y channels, if there is an unused channel in the other N branching splitter, the one channel is constructed after the PON optical network is constructed. The unused channels may be allocated to subscriber apparatuses connected to the N branch splitters one by one according to the predetermined allocation direction .
In the single N branch splitter, wherein the y-number of channels and the unused channel assigning channels to subscribers device connected to said one N branch splitter After building the optical network of the PON system If this is not possible, together with the other station device (12), at least one (L / (2) of the other station device (12) and the one N-branch splitter are connected. Multiple)) branch splitters (41, 42) are newly installed as equipment in the communication station, and the channel allocation device (15) is connected to all of the subscriber devices connected to the one N branch splitter. It may also be used to allocate channels one by one from the station equipment (12) .
When all of the plurality of station devices (11, 12) are installed as equipment in the communication station by newly installing the other station devices (12) , the channel allocation device (15) However, it may also be used to allocate one channel at a time from the plurality of station devices (11, 12) to the N × M subscriber devices.
When the plurality of station devices (11, 12) are all installed as equipment in a communication station, the at least one L branch splitter (21, 22) has at least one other (L / (2 Multiple))) may be replaced by a branching splitter.
The plurality of central office equipment (11, 12) is in the case of having a channel that overlap each other, the channel allocation device (15), respectively connected to the channels of the M N branch splitter that overlap each other so as not assigned to a subscriber device of N pieces each, be also used to assign the channel one by one to the N × M pieces of subscriber equipment from the plurality of stations for device (11, 12) Good.
When one station apparatus (11) of the required number of station apparatuses includes two optical interfaces having overlapping channels, the PON optical network is constructed. Initially, two L-branch splitters (21, 22) are installed as equipment in the communication station, and one of the one station device (11) and the two L-branch splitters (21, 22) One L-branch splitter (21) is connected via an optical fiber to which a channel of one of the two optical interfaces is assigned, and the one station device (11 ) And the other L branch splitter (22) of the two L branch splitters (21, 22) are connected to the other optical interface of the two optical interfaces. Tunnel is connected through an optical fiber is assigned,
When the other station device (12) is provided with two other optical interfaces having overlapping channels, the other station device (12) is newly added as a communication station facility. When installed, two (L / (multiple of 2)) branching splitters (41, 42) are newly installed as equipment in the communication station, and the other station devices (12) and the two One (L / (multiple of 2)) branch splitter (41) of the (L / (multiple of 2)) branch splitters (41, 42) is one of the two other optical interfaces. The other optical interface channel is connected via an assigned optical fiber, and the other station device (12) and the two (L / (multiple of 2)) branch splitters (41, 42) the other one (L / (multiple of 2)) Branch splitter (42), but the two other other other via an optical fiber channel is assigned the optical interface may be coupled out of the optical interface.

The PON optical transmission system of the present invention has the following effects.
(1) Even when M N-branch splitters are installed on the line and N × M subscriber devices are connected, the initial construction of the optical network is (N × M) / (multiple of 2). Because it is sufficient to install the necessary number of station devices as equipment in the communication station building to connect the subscriber equipment, it is possible to greatly reduce the initial investment of the communication station equipment and the space for accommodating communication equipment. Can do.
(2) Allotting y consecutive channels out of x channels to subscriber units connected to one N branch splitter of M N branch splitters according to a predetermined allocation direction, The subscriber unit connected to one N-branch splitter is provided with z (z is less than or equal to xy) of the remaining (xy) channels out of the x channels. Even if it becomes impossible to assign a channel to a subscriber unit with y channels in the one N-branch splitter by assigning according to an assignment direction opposite to a predetermined assignment direction, the other one N An empty channel in the branching splitter can be delivered efficiently.

  The purpose of drastically reducing the initial investment of communication station facilities and the space for accommodating communication equipment is to (N × M) / (multiple of 2) subscriber devices out of N × M subscriber devices. Only the necessary number of station devices for allocating channels, and the necessary number of channels from the necessary number of station devices to (N × M) / (multiple of 2) subscriber devices. From one station device to one subscriber device connected to one N-branch splitter of M N-branch splitters, y consecutive out of x channels The channels are allocated according to a predetermined allocation direction, and the remaining (xy) of the x channels are transmitted to the subscriber unit connected to the other N branch splitter of the M N branch splitters. Channel of An optical transmission system comprising a channel allocating device used for allocating z consecutive channels (z is xy or less) according to an allocation direction opposite to the predetermined allocation direction as equipment in a communication station It was realized.

Hereinafter, embodiments of the PON optical transmission system of the present invention will be described with reference to the drawings.
The PON optical transmission system according to an embodiment of the present invention finally has 8 (M) installed on a line from two station devices each including two optical interfaces each having 1 to 32 ch channels. = 8) Used when wiring an optical fiber up to 16 branch splitters (N branch splitter: N = 16) so that 128 (= N × M) subscriber devices can be connected. .

First, the configuration of a PON optical transmission system 1 (hereinafter referred to as “optical transmission system 1”) according to the present embodiment at the time of constructing an optical network will be described with reference to FIGS.
As shown in FIG. 1, the optical transmission system 1 is installed as a station apparatus 11 installed as a communication station facility, a channel assignment device 15 installed as a communication station facility, and a communication station facility. First and second 4-branch splitters 21 and 22 (L-branch splitter: L = 4), and first to eighth 16-branch splitters 31 to 38 (8 (M = 8)) installed on the line. N branch splitters: N = 16). That is, the optical transmission system 1 has only one station apparatus at the beginning of constructing the optical network.

  Here, the station apparatus 11 includes first and second optical interfaces (not shown) each having 1 to 32 ch channels.

  The first four-branch splitter 21 includes one optical fiber to which channels 1 to 32 of the first optical interface of the station apparatus 11 are allocated, and an allocated channel range of 1 to 8 channels of the first optical interface. One optical fiber, one optical fiber whose assigned channel range is 9 to 16 ch of the first optical interface, and one optical fiber whose assigned channel range is 17 to 24 ch of the first optical interface; The assigned channel range branches to one optical fiber having 25 to 32 ch of the first optical interface.

  The second four-branch splitter 22 is a single optical fiber to which channels 1 to 32 of the second optical interface of the station apparatus 11 are allocated, and the allocated channel range is 1 to 8 of the second optical interface. An optical fiber, one optical fiber whose assigned channel range is 9 to 16 ch of the second optical interface, and one optical fiber whose assigned channel range is 17 to 24 ch of the second optical interface; The assigned channel range branches to one optical fiber having 25 to 32 channels of the second optical interface.

The first 16-branch splitter 31 branches the optical fiber from the first 4-branch splitter 21 whose assigned channel range is 1 to 8 ch of the first optical interface from the first core line to the 16th core line.
The second 16-branch splitter 32 branches the optical fiber from the first 4-branch splitter 21 whose assigned channel range is 9 to 16 ch of the first optical interface from the first core line to the 16th core line.
The third 16-branch splitter 33 branches the optical fiber from the first 4-branch splitter 21 whose assigned channel range is 17 to 24 ch of the first optical interface from the first core line to the 16th core line.
The fourth 16-branch splitter 34 branches the optical fiber from the first 4-branch splitter 21 whose assigned channel range is 25 to 32 ch of the first optical interface from the first core line to the 16th core line.

The fifth 16-branch splitter 35 branches the optical fiber from the second 4-branch splitter 22 whose assigned channel range is 1 to 8 ch of the second optical interface from the first core line to the 16th core line.
The sixth 16-branch splitter 36 branches the optical fiber from the second 4-branch splitter 22 whose assigned channel range is 9 to 16 ch of the second optical interface from the first core line to the 16th core line.
The seventh 16-branch splitter 37 branches the optical fiber from the second 4-branch splitter 22 whose assigned channel range is 17 to 24 ch of the second optical interface from the first core line to the 16th core line.
The eighth 16-branch splitter 38 branches the optical fiber from the second 4-branch splitter 22 whose assigned channel range is 25 to 32 ch of the second optical interface from the first core line to the 16th core line.

  As shown in FIG. 2, the channel allocation device 15 branches 16 to 32 channels of the first optical interface of the station device 11 from the first to fourth 16-branch splitters 31 to 34, respectively. Are assigned to only the subscriber devices connected to eight of the core wires (No. 1 to No. 16 core wires), and as shown in FIG. 8 to 16 channels (1st to 16th cores) branched from the 5th to 8th 16-branch splitters 35 to 38 through the channels 1 to 32ch of the optical interface. It is used for assigning only to subscriber devices connected to the core wire.

  Accordingly, although 16 subscriber devices can be connected to the first to eighth 16-branch splitters 31 to 38, channels can only be assigned to only 8 subscriber devices. However, there is no particular problem because the number of subscribers is small at the beginning of the construction of the optical network.

The channel assignment is performed as follows.
The subscriber apparatus connected to eight of the 16 cores branched from the first 16-branch splitter 31 has the order of 1ch to 8ch of the first optical interface of the station apparatus 11. In the subscriber apparatus connected to 8 of the 16 cores branched from the second 16-branch splitter 32, the first light of the station apparatus 11 is assigned. Channels are assigned in the order of 16ch to 9ch of the interface. The subscriber apparatus connected to 8 of the 16 cores branched from the third 16-branch splitter 33 has channels 17 to 24 of the first optical interface of the station apparatus 11. On the other hand, the subscriber apparatus connected to eight of the 16 cores branched from the fourth 16-branch splitter 34 is assigned to the first of the station apparatus 11. Channels are assigned in the order of 32 ch to 25 ch of the optical interface.

  That is, as shown by the arrows in FIG. 2, for the first optical interface of the station apparatus 11, the channel allocation direction allocated to the subscriber apparatus is reversed between 1-8 ch and 9-16 ch, In 17-24ch and 25-32ch, the channel allocation direction allocated to the subscriber apparatus is reversed.

  Similarly, the subscriber apparatus connected to eight of the 16 cores branched from the fifth 16-branch splitter 35 is connected to 1ch of the second optical interface of the station apparatus 11. While the channels are assigned in the order of 8 channels, the subscriber apparatus connected to 8 of the 16 cores branched from the sixth 16-branch splitter 36 has the number of stations of the station apparatus 11. Channels are assigned in the order of 16 ch to 9 ch of the second optical interface. Further, the channel allocation device 15 is connected to the subscriber device connected to eight of the 16 core wires branched from the seventh 16-branch splitter 37, and the second device of the station device 11 While the channels are assigned in the order of 17ch to 24ch of the optical interface, the subscriber unit connected to 8 of the 16 cores branched from the eighth 16-branch splitter 38 has a station Channels are assigned in the order of 32 ch to 25 ch of the second optical interface of the device for use 11.

  That is, as indicated by the arrows in FIG. 3, the channel allocation direction allocated to the subscriber apparatus is reversed between 1-8 ch and 9-16 ch for the second optical interface of the station apparatus 11, and , 17-24ch and 25-32ch, the channel assignment direction assigned to the subscriber apparatus is reversed.

  Further, for example, when the number of subscribers increases in the area where the first 16-branch splitter 31 is installed and more than 8 channels are required, 8 of the 16 core wires branched from the second branch splitter 32 are used. When 9 to 14 ch of 9 to 16 ch assigned to the core wire remain as unused channels (see FIG. 2), as shown in FIG. 4, for example, among the unused channels 9 to 14 ch, When 9 to 12 ch are assigned 1 to 8 ch to the remaining 4 cores of the 16 cores that are not assigned to the 16 cores branched from the first branching splitter 31. Are assigned in the same assignment direction (that is, the order from 9ch to 12ch). For the 16 core wires branched from the second branching splitter 32, only four channels 13 to 16ch can be assigned.

  As described above, the first and second 16 branches of the first optical interface of the station apparatus 11 are made by reversing the allocation directions of the channels allocated to the subscriber apparatuses in 1 to 8 ch and 9 to 16 ch. The channel can be easily transferred between the splitters 31 and 32.

  Similarly, for example, if more subscribers are required in the area where the fourth 16-branch splitter 34 is installed and more than 8 channels are required, 8 of the 16 core wires branched from the third branch splitter 33 are used. When 19 to 24 ch of 17 to 24 ch assigned to the core are left as unused channels (see FIG. 2), as shown in FIG. 4, of the unused channels 19 to 24 ch, For example, channels 22 to 24 are allocated to 3 of the remaining 8 cores of the 16 cores branched from the fourth branching splitter 34, and are allocated to 25 to 32 channels. Are assigned in the same assignment direction (that is, the order from 24 ch to 22 ch). For the 16 core wires branched from the third branching splitter 33, only five channels 17 to 21ch can be assigned.

  As described above, the third and fourth 16 branches are made by reversing the channel assignment directions assigned to the subscriber devices in the first optical interface of the station apparatus 11 in 17-24 ch and 25-32 ch. The channel can be easily transferred between the splitters 33 and 34.

  Next, in the area where the first and seventh 16-branch splitters 31 and 37 are installed, the number of subscribers increases to require 12 channels and 8 channels or more (that is, 128 subscribers with the station apparatus 11 alone). A change in the configuration of the optical transmission system 1 when a channel cannot be assigned to any one of the subscriber devices will be described with reference to FIGS. 5 and 6.

  When the number of subscribers increases in the area where the first and seventh 16-branch splitters 31 and 37 are installed and 12 channels and 8 channels or more are required, as shown in FIG. The second two-branch splitters 41 and 42 ((L / 2) branch splitter: L = 4) are newly installed as communication station facilities.

Here, the other station apparatus 12 includes third and fourth optical interfaces having channels 1 to 32 ch, respectively.
The first two-branch splitter 41 uses a single optical fiber to which channels 1 to 32 of the third optical interface of the other station apparatus 12 are allocated, and a channel allocation range is 1 to 16 of the third optical interface. The optical fiber branches into one optical fiber and one optical fiber whose channel allocation range is 17 to 32 ch of the third optical interface.
The second two-branch splitter 42 uses one optical fiber to which channels 32 to 32 of the fourth optical interface of the other station apparatus 12 are allocated, and a channel allocation range is 1 to 16 channels of the fourth optical interface. The optical fiber branches into one optical fiber and one optical fiber whose channel allocation range is 17 to 32 ch of the fourth optical interface.

  When another station apparatus 12 and the first and second two-branch splitters 41 and 42 are newly installed, the optical fiber communication station where the channel allocation range is 1 to 12 ch of the first optical interface. As shown by a dotted line in FIG. 5, the end on the inner equipment side is disconnected from the first four-branch splitter 21 and connected to a newly installed first two-branch splitter 41. Similarly, the end of the optical fiber whose channel allocation range is 17 to 24 ch of the second optical interface on the equipment side in the communication station is removed from the second four-branch splitter 22 and newly installed. 1 to a two-branch splitter 41.

The channel assignment range of the optical fiber that is removed from the first four-branch splitter 21 and connected to the first two-branch splitter 41 using the channel assignment device 15 is as shown in the bottom table of FIG. In addition, the first optical interface 1 to 12 ch is changed to the third optical interface 1 to 16 ch of another newly installed station apparatus 12.
Further, the channel assignment range of the optical fiber that is disconnected from the second four-branch splitter 22 and connected to the first two-branch splitter 41 using the channel assignment device 15 is as shown in the bottom table of FIG. The second optical interface is changed from 17 to 24 ch to the third optical interface 17 to 32 ch of another newly installed station apparatus 12.
Further, using the channel allocation device 15, the first optical interface 1 to 12 ch of the station apparatus 11 that was the channel allocation range of the optical fiber removed from the first four-branch splitter 21, and the second 4 As shown in the uppermost and middle tables of FIG. 6, the second optical interface 17 to 24 ch of the station apparatus 11, which was the channel assignment range of the optical fiber removed from the branching splitter 22, Is done.

  As a result, the subscriber apparatus connected from the first core line to the sixteenth core line branched from the first 16-branch splitter 31 is connected with 1 to 16 ch of the third optical interface of the other station apparatus 12. Each of the third optical interfaces of the other station apparatuses 12 can be assigned to each of the subscriber apparatuses connected from the first core line to the sixteenth core line branched from the seventh 16-branch splitter 37. Since 17 to 32 channels can be allocated, it is possible to cope with an increase in subscribers in the area where the first and seventh 16-branch splitters 31 and 37 are installed.

  Then, after that, subscribers increase in the areas where the second, fourth, fifth and sixth 16-branch splitters 32, 34, 35, and 36 are installed to increase the number of channels 4, 11, 8 and 8 channels. A change in the configuration of the optical transmission system 1 when necessary will be described with reference to FIGS.

  In order to cope with the increase in subscribers in the area where the fourth and fifth 16-branch splitters 34 and 35 are installed, as shown by the dotted line in FIG. 7, the channel allocation range is 22 to 32 ch of the first optical interface. The end of the optical fiber on the equipment side in the communication station is removed from the first four-branch splitter 21 and connected to the second two-branch splitter 42, and the channel allocation range is the second optical interface. 1 to 8 ch of the optical fiber on the equipment side in the communication station are removed from the second four-branch splitter 22 and connected to the second two-branch splitter 42.

  Then, using the channel allocation device 15, as shown in the lowermost table of FIG. 8, the channel allocation range of the optical fiber removed from the first four-branch splitter 21 and connected to the second two-branch splitter 42. Is changed from 22 to 32 ch of the first optical interface to 17 to 32 ch of the fourth optical interface of the other station apparatus 12 and is removed from the second four-branch splitter 22 and the second 2 The channel assignment range of the optical fiber connected to the branching splitter 42 is changed from 1 to 8 ch of the second optical interface to 1 to 16 ch of the fourth optical interface of the other station apparatus 12.

  Further, the channel allocation range of the optical fiber (indicated by a one-dot chain line in FIG. 7) connected to the second 16-branch splitter 32 using the channel allocation device 15 is as shown in the uppermost table of FIG. The optical fiber (shown by a one-dot chain line in FIG. 7) is changed from 13 to 16 ch of the first optical interface to 1 to 16 ch of the first optical interface and connected to the sixth 16-branch splitter 36. The channel allocation range is changed from 9 to 16 ch of the second optical interface to 1 to 16 ch of the second optical interface, as shown in the second table of FIG.

  As a result, since only two optical fibers are connected to the 16-branch splitter for each of the first and second 4-branch splitters 21 and 22, the third and fourth 2-branch splitters (not shown) are connected to the communication station. It will be newly installed as a facility in the building. The two optical fibers connected to the first four-branch splitter 21 are disconnected from the first four-branch splitter 21 and connected to the newly installed third two-branch splitter. The two optical fibers connected to the second four-branch splitter 22 are disconnected from the second four-branch splitter 22 and connected to the newly installed fourth two-branch splitter.

  The channel allocation range of the optical fiber connected from the newly installed third 2-branch splitter to the third 16-branch splitter 33 using the channel allocation device 15 is shown in the uppermost table of FIG. As described above, the first optical interface 17-24ch is changed to the first optical interface 17-32ch, and the newly installed fourth 2-branch splitter is connected to the eighth 16-branch splitter 38. The channel allocation range of the optical fiber is changed from 25 to 32 ch of the second optical interface to 17 to 32 ch of the second optical interface, as shown in the second table of FIG.

In the above description, 64 (= (N × M) / 2) subscribers out of 128 subscriber units connected to 8 (M = 8) 16-branch splitters (N = 16). In the optical transmission system 1 at the beginning of the construction of the optical network, the first and second four-branch splitters 21 and 22 are installed as the equipment in the communication station so as to allocate the channels only to the devices. In this way, the number of serviceable subscriber devices may be increased by a multiple of two.
(1) 64 (= (N × M) / (2 × 2)) subscriptions out of 256 subscriber units connected to 16 (M = 16) 16 branch splitters (N = 16) In the optical transmission system 1 at the beginning of the construction of the optical network, the first and second 8-branch splitters are provided in place of the first and second 4-branch splitters 21 and 22 so that the channels are allocated only to the user devices Installed.
(2) 64 of 512 subscriber devices connected to 32 (M = 32) 16 branch splitters (N = 16) (= (N × M) / (2 × 2 × 2)) Instead of the first and second four-branch splitters 21 and 22, the optical transmission system 1 at the beginning of the construction of the optical network has the first and second 16 branches so that the channels are allocated only to the subscriber devices of A splitter is installed.

  Further, the case where the 16-branch splitter is installed on the line has been described as an example. However, for example, when an 8-branch splitter and a 32-branch splitter are also installed, N Only the number of station devices required to allocate channels to (N × M) / (multiple of 2) subscriber devices out of M subscriber devices is installed as equipment in the communication station. You can just make it.

  Furthermore, as shown in FIGS. 2 and 3, at the beginning of the construction of the optical network, the channel allocation range of the four optical fibers branched by the same four-branch splitter is set to 8 consecutive channels. , It does not have to be continuous.

  Furthermore, as shown in FIGS. 2 and 3, at the beginning of the construction of the optical network, the channel allocation range of the four optical fibers branched by the same four-branch splitter was set to 8 channels each. Depending on the initial number of subscribers in the installed area, the number of channels in the channel allocation range of these four optical fibers may be changed.

  As described above, the PON optical transmission system of the present invention can be used, for example, to connect a plurality of subscriber devices by branching one optical fiber into a plurality of branches in a accommodating station.

It is a figure which shows the structure at the time of construction of the optical network of the PON system optical transmission system by one Example of this invention. Example 1 It is a figure which shows the relationship between the 1st thru | or 4th 16 branch splitters 31-34 determined at the time of construction of an optical network by the channel allocation apparatus 15 shown in FIG. 1, and an allocation channel range. Example 1 It is a figure which shows the relationship between the 5th thru | or 8th 16 branch splitters 35-38 determined by the channel allocation apparatus 15 shown in FIG. 1 at the time of construction of an optical network, and an allocation channel range. Example 1 The channel delivery between the first and second 16-branch splitters 31 and 32 shown in FIG. 1 and the channel delivery between the third and fourth 16-branch splitters 33 and 34 shown in FIG. 1 will be described. FIG. Example 1 It is a figure for demonstrating the connection of the optical fiber when another station apparatus is newly installed, and the change of the allocation channel range by the channel allocation apparatus 15 shown in FIG. Example 1 It is a figure which shows the relationship between the 1st thru | or 8th 16 branch splitters 31-38 after the change shown in FIG. 5, and an allocation channel range. Example 1 It is a figure for demonstrating the change of the connection of the optical fiber by the channel allocation apparatus 15 shown in FIG. 1 after the other station apparatus is newly installed, and the allocation channel range. Example 1 It is a figure which shows the relationship between the 1st thru | or 8th 16 branch splitters 31-38 after the change shown in FIG. 7, and an allocation channel range. Example 1 It is a figure for demonstrating the conventional PON system optical transmission system. It is a figure which shows the relationship between the 1st thru | or 8th 16 branch splitters 131-138 shown in FIG. 9, and an allocation channel range.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical transmission system 11 Station apparatus 12 Other station apparatus 15 Channel allocation apparatus 21,22 4 branch splitters 31-38 16 branch splitter 41,42 2 branch splitter

Claims (7)

M N-branch splitters (31 to 38) are installed on the line so that N × M subscriber devices can be connected, and a plurality of station devices (11, 12) are connected to the N × A PON optical transmission system used in a PON optical network constructed by assigning channels to M subscriber devices one by one ,
The installed initially to construct an optical network of PON type as the communication station building facilities, and the need to assign one channel only (N × M) / (a multiple of 2) number of subscriber units A number of station devices (11),
Initially constructed as a PON optical network, installed as communication station equipment, and the necessary number of station devices (11) and all of the M N branch splitters (31 to 38) At least one L-branch splitter (21, 22) for connecting via an optical fiber;
It was installed as equipment in a communication station at the beginning of constructing the PON optical network, and at the beginning of constructing the PON optical network, the M pieces of the necessary number of station devices (11) are used. One channel is allocated to at least one subscriber unit connected to each N-branch splitter of the N-branch splitters (31 to 38) and a total of (N × M) / (multiple of 2) subscriber units. A channel assignment device (15) for assigning channels one by one to
At the beginning of the construction of the PON optical network, the channel allocation device (15) starts from one of the required number of station devices (11) to the M N-branch splitters. (31) to (31), to the subscriber device connected to one N-branch splitter, y consecutive channels out of x channels are allocated one by one according to a predetermined allocation direction, and the M channels Z of the remaining (xy) channels of the x channels to a subscriber unit connected to another N branch splitter of the N branch splitters (31 to 38) Allocating one (z is less than or equal to xy) consecutive channels one by one according to an allocation direction opposite to the predetermined allocation direction,
At the beginning of the construction of the PON optical network, only the necessary number of station devices (11) are installed as equipment in the communication station, and the number of subscribers is increased after the construction of the PON optical network. Increasingly, the number of subscriber devices connected to at least one N-branch splitter among the M N-branch splitters (31 to 38) increases, and the necessary number of station devices (11). If it becomes impossible to allocate a channel only by installing another station device (12) among the plurality of station devices (11, 12) as equipment in a communication station, The number of station devices to be installed as equipment in the communication station at the beginning of constructing the PON optical network with a small number of subscribers was reduced.
A PON type optical transmission system. After the channel allocation device (15) constructs the PON optical network, the number of subscribers increases, and the number of subscriber devices connected to the one N-branch splitter increases. If it is impossible to assign a channel to a single channel, and there is an unused channel in the other N branching splitter, the N branching is performed after the PON optical network is constructed. 2. The PON optical transmission system according to claim 1 , wherein the unused channels are allocated to subscriber devices connected to the splitter one by one in accordance with the predetermined allocation direction . In the single N branch splitter, wherein the y-number of channels and the unused channel assigning channels to subscribers device connected to said one N branch splitter After building the optical network of the PON system If this is not possible, together with the other station device (12), at least one (L / (2) of the other station device (12) and the one N-branch splitter are connected. Multiple))) Branch splitter (41, 42) is newly installed as equipment in the communication station,
The channel assignment device (15) is also used to assign a channel from the other station device (12) one by one to all of the subscriber devices connected to the one N-branch splitter.
The PON optical transmission system according to claim 2, wherein: When all of the plurality of station devices (11, 12) are installed as equipment in the communication station by newly installing the other station devices (12) , the channel allocation device (15) PON of but characterized by a Turkey also used to assign each channel one in the N × M pieces of subscriber equipment from the plurality several office device (11, 12), according to claim 3, wherein Optical transmission system. When the plurality of station devices (11, 12) are all installed as equipment in a communication station, the at least one L branch splitter (21, 22) has at least one other (L / (2 multiples)), wherein a is replaced Turkey branch splitter, PON system optical transmission system according to claim 4. The plurality of central office equipment (11, 12) is in the case of having a channel that overlap each other, the channel allocation device (15), respectively connected to the channels of the M N branch splitter that overlap each other so as not assigned to a subscriber device of N pieces each, also be used to allocate from the plurality of stations for device (11, 12) the channel one by one to the N × M pieces of subscriber equipment The PON optical transmission system according to claim 4 or 5, characterized in that When one station apparatus (11) out of the required number of station apparatuses includes two optical interfaces having overlapping channels,
At the beginning of constructing the PON optical network,
Two L-branch splitters (21, 22) are installed as equipment in the communication station,
The one station device (11) and one L-branch splitter (21) of the two L-branch splitters (21, 22) are connected to one of the two optical interfaces. The interface channel is connected via an assigned optical fiber, and the other L branch of the one station device (11) and the two L branch splitters (21, 22). A splitter (22) is connected via an optical fiber to which the channel of the other of the two optical interfaces is assigned;
If the other station device (12) comprises two other optical interfaces having overlapping channels,
When the other station device (12) is newly installed as equipment in the communication station,
Two (L / (multiple of 2)) branching splitters (41, 42) are newly installed as equipment in the communication station,
The other station device (12) and one (L / (multiple of 2)) branch splitter (41) out of the two (L / (multiple of 2)) branch splitters (41, 42) Are connected via an optical fiber to which the channel of one other optical interface of the two other optical interfaces is assigned, and the other station apparatus (12) and the two optical interfaces. The other (L / (multiple of 2)) branch splitter (42) of the (L / (multiple of 2)) branch splitters (41, 42) is connected to the two other optical interfaces. The other optical interface channel of the other is connected via an assigned optical fiber,
The PON optical transmission system according to claim 3, wherein the optical transmission system is a PON optical transmission system.

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