JP5466543B2 - PON system, station side device, and subscriber side device - Google Patents

Description

  The present invention relates to a PON (Passive Optical Network) system and a technology for using surplus bandwidth in a station side device and a subscriber side device constituting the PON system.

  2. Description of the Related Art Conventionally, a passive optical network (PON) system is known as a subscriber optical fiber network system for a subscriber house such as a general home. In this PON system, a single optical fiber connected to an optical line terminal (OLT) is branched by an optical splitter and connected to a plurality of subscriber side apparatuses (ONU: Optical Network Unit). This is an optical transmission system in which a user shares one optical fiber (see, for example, Patent Document 1).

JP 2007-281979 A

  However, in a 10G-EPON (Ethernet (registered trademark) PON) system with a communication speed of 10 Gbps, there is redundancy such as adding a parity code for FEC, and a bandwidth of about 10 Gbps in the PON line section between the ONU and the OLT. Of these, the maximum bandwidth is limited to about 8.7 Gbps and the maximum downstream is about 9.7 Gbps. On the other hand, a dedicated line connected to an L2SW or router on the upper side of the OLT has a bandwidth of 10 Gbps. For this reason, there is a surplus bandwidth of about 1.3 Gbps upstream and about 0.3 Gbps downstream between the bandwidth of the PON line on the lower side of the OLT and the bandwidth of the higher side line, and effective use of the bandwidth is possible. There was a problem that it was not planned.

  An object of the present invention is to provide a PON system, a station-side device, and a subscriber side that can effectively use a surplus bandwidth between a bandwidth of a PON line lower than the OLT and a bandwidth of a higher-order line in the PON system. Is to provide a device.

The PON system according to the present invention is a PON system comprising a subscriber side device for connecting a user terminal and a station side device for connecting a plurality of the subscriber side devices via a PON line. A transmission buffer that temporarily holds transmission data of the user terminal, a data compression unit that compresses transmission data held in the transmission buffer, and a transmission request that includes the transmission data amount of the transmission buffer in the station side device A subscriber-side control unit that transmits a control frame, receives a transmission permission control frame including a data transmission start timing and a data transmission continuation time from the station side device, and transmits compressed data of the transmission buffer. The station side device includes a data decompression unit that decompresses the compressed data received from the subscriber side device, and transmission data notified from each subscriber side device. The amount of traffic, the upstream PON line speed information of the subscriber side device, and the upper side line speed information are used to calculate the upstream traffic amount of the subscriber side device, and the subscriber side device connects A data transmission start timing and a data transmission continuation time to the PON line to be transmitted, a transmission permission control frame including the data transmission start timing and the data transmission continuation time is transmitted to the subscriber side device, and that having a the station side control unit that transmits the data frame to data decompression section is extended to the upper side line.

Then , the subscriber-side control unit of the subscriber-side device includes the data compression unit including a data compression rate for transmission data of the transmission buffer in the transmission request control frame, and transmits the data to the station-side device. The station-side control unit of the device compares a plurality of data compression rates included in the transmission request control frames received from the plurality of subscriber-side devices, and determines to the subscriber-side device having a relatively low compression rate. The upstream communication volume of each subscriber side device is calculated so as to widely allocate the upstream band of the PON line, the data transmission start timing and the data transmission duration time to the PON line to which each subscriber side device is connected, It is characterized by calculating | requiring.

A subscriber-side device according to the present invention is a transmission buffer for temporarily storing transmission data of a user terminal in a subscriber-side device that is accommodated by a PON line in a station-side device of a PON system and transmits user terminal data. A data compression unit that compresses the transmission data held in the transmission buffer; and a transmission request control frame that includes the transmission data amount of the transmission buffer is transmitted to the station side device, and a data transmission start timing is transmitted from the station side device. And a subscriber-side control unit that receives the transmission permission control frame including the data transmission duration and transmits the compressed data of the transmission buffer .

The subscriber-side control unit is characterized in that the data compression unit includes a data compression rate for transmission data in the transmission buffer in the transmission request control frame and transmits the data to the station-side device.

A station-side device according to the present invention is a data-decompression unit that decompresses compressed data received from a subscriber-side device in a station-side device of a PON system that accommodates a plurality of subscriber-side devices connected to user terminals via a PON line. The subscriber data using the transmission request control frame transmitted from each subscriber-side device, the upstream PON line speed information of the subscriber-side apparatus, and the higher-side line speed information. A communication amount in the upstream direction of the side device is calculated, a data transmission start timing and a data transmission duration time to the PON line to which the subscriber side device is connected are obtained, and the data transmission start timing and the data transmission duration time are obtained. And a transmission permission control frame including the data frame to the subscriber side device, and the station side control for transmitting the data frame expanded by the data expansion unit to the upper line. It provided the department.

The station-side control unit compares a plurality of data compression rates included in the transmission request control frames received from the plurality of subscriber-side devices, and determines whether the compression rate is relatively low. The upstream communication volume of each subscriber side device is calculated so as to widely allocate the upstream band of the PON line, the data transmission start timing and the data transmission duration time to the PON line to which each subscriber side device is connected, It is characterized by calculating | requiring.

The front Symbol provided different dedicated subscriber terminal and the subscriber-side apparatus connected to the station apparatus via a dedicated line that is wavelength-multiplexed in the PON line in a different band than PON line, the station-side device A demultiplexing unit that multiplexes and demultiplexes data transmitted and received between the plurality of subscriber-side devices and the higher-level line; and management of the plurality of subscriber-side devices accommodated in each station-side device And a communication unit that communicates with the dedicated subscriber terminal via a dedicated line wavelength-multiplexed with the PON line in a band different from the PON line, and the demultiplexing unit includes: The dedicated subscriber in which the communication unit multiplexes the data received from the dedicated subscriber terminal with the data received from the plurality of subscriber side devices and transmits the multiplexed data to the upper line and separates the data received from the upper line Device-specific data And transmits the data to the private subscriber terminal via the communication unit.

  In particular, the dedicated subscriber terminal is an IP phone.

  Since the PON system, the station-side device, and the subscriber-side device according to the present invention can effectively use the surplus bandwidth between the bandwidth of the PON line on the lower side of the OLT and the bandwidth of the higher-side line. System costs can be reduced and services can be improved.

1 is a diagram illustrating a configuration example of a PON system 100 according to a first embodiment. It is a figure which shows the structural example of OLT101. 2 is a diagram illustrating a configuration example of an ONU 102. FIG. 2 is a diagram illustrating a configuration example of an ONU 103. FIG. 2 is a diagram showing a configuration example of an IP phone 106. FIG. It is a figure which shows the structural example of the PON system 100c which concerns on 2nd Embodiment. It is a figure which shows the structural example of the PON control part 303c of ONU102c. It is a figure which shows the structural example of the PON control part 203c of OLT101c. 1 is a diagram illustrating a configuration example of a general PON system 900. FIG. 2 is a diagram illustrating an example of a bandwidth of a PON system 900. FIG.

  Hereinafter, embodiments of the PON system, the station side apparatus, and the subscriber side apparatus according to the present invention will be described in detail with reference to the drawings.

  First, a general PON system will be described so that the features of each embodiment can be easily understood.

[General PON system]
FIG. 9 is a configuration diagram of a PON system 900 that uses 10G-EPON with a communication speed of 10 Gbps and GE (Gigabit Ethernet (registered trademark))-PON with a communication speed of 1 Gbps. The PON system 900 shown in FIG. 9 includes a station side device (OLT) 901, a 10G-EPON subscriber side device (ONU) 902, a GE-PON subscriber side device (ONU) 903, and an optical splitter 904. It consists of and. The OLT 901 is connected to a higher-level communication apparatus (L2SW, router, etc.) via a 10 Gbps line via an SNI (Service Node Interface).

  In the PON system 900, time division multiplexing (TDM) is used for the uplink from the ONUs 902 and 903 to the OLT 901, and wavelength division multiplexing (WDM) is used for the downlink from the OLT 901 to the ONUs 902 and 903. Here, for example, the upstream optical wavelength is 1.31 μm, the 10G-EPON downstream optical wavelength is 1.49 μm, and the GE-PON downstream optical wavelength is 1.57 μm, for example. As described above, in the PON system, signals of a plurality of lines are wavelength-multiplexed and used on one optical fiber.

  In FIG. 9, for example, in the case of an uplink, 10 Gbps data A transmitted by the ONU 902 and 1 Gbps data B transmitted by the ONU 903 are transmitted at different timings according to the transmission timing given in advance from the OLT 901, and are transmitted through the optical splitter 904. The data is divided and multiplexed and input to the OLT 901. On the other hand, in the case of the downlink, the 10 Gbps data E transmitted from the OLT 901 to the ONU 902 and the 1 Gbps data F transmitted from the OLT 901 to the ONU 903 are wavelength multiplexed and input to both the ONUs 902 and 903 via the optical splitter 904. Since each data has a frame structure to which a pre-assigned LLID (logical link ID) is added for each ONU, the ONU 902 receives the data E of the frame matching its own LLID and discards the data F To do. Similarly, the ONU 903 receives the data F of the frame that matches its own LLID, and discards the data E. In this way, the ONUs 902 and 903 receive data addressed to them from the OLT 901.

  Here, in FIG. 9, the uplink line speed is 10 Gbps, and the downlink line speed is 11 Gbps.

  However, 10G-EPON with a line speed of 10 Gbps has an overhead of an RS parity code (RS (255, 223)) for FEC in the 10 Gbps band, so the maximum throughput of the transmitted Ethernet frame is about 8.7 Gbps. (In the following description, approximately 8.7 is omitted and described as 8.7 Gbps). In addition, since a 1 Gbps GE-PON has a 1.25 Gbps band including overhead, the maximum throughput is about 1 Gbps (in the following description, about is omitted and described as 1 Gbps). Here, in this specification, the actually usable communication speed is referred to as a band. In the above case, the bandwidth of 10G-EPON is 8.7 Gbps, and the bandwidth of GE-PON is 1 Gbps.

  For example, the bandwidth of each part of the uplink of the PON system 900 shown in FIG. 9 has values as shown in FIG. In FIG. 10 (a), the bandwidth of the uplink from the optical splitter 904 to the OLT 901 is 8.7 Gbps. Therefore, when 1 Gbps is allocated to the ONU 903, the bandwidth of the ONU 904 is limited to 7.7 Gbps instead of 8.7 Gbps. The The OLT 901 transfers 8.7 Gbps data including the maximum 7.7 Gbps data received from the ONU 902 and the maximum 1 Gbps data received from the ONU 903 to the L2SW 905 of the host communication device. However, since the bandwidth of the dedicated line from the OLT 901 to the L2SW 905 is 10 Gbps, a surplus bandwidth of 1.3 Gbps is generated.

  Similarly, the bandwidth of each part of the downlink of the PON system 900 shown in FIG. 9 has values as shown in FIG. In FIG. 10B, since the data from the OLT 901 to the ONU 902 and ONU 903 are wavelength-multiplexed, the downlink bandwidth to the ONU 902 is 8.7 Gbps at maximum and the downlink bandwidth to the ONU 903 is 1 Gbps at maximum. However, although the maximum downlink from the OLT 901 to each ONU is 9.7 Gbps, the bandwidth of the dedicated line from the upper communication device L2SW 905 to the OLT 901 is 10 Gbps, so a surplus bandwidth of 0.3 Gbps is generated.

  Thus, the conventional PON system 900 does not effectively use the surplus bandwidth between the bandwidth of the PON line on the lower side of the OLT and the bandwidth of the dedicated line on the upper side.

  Therefore, in the PON system, the station side device, and the subscriber side device according to the present invention, the surplus bandwidth between the bandwidth of the PON line on the lower side of the OLT 901 and the bandwidth of the upper side line can be effectively used, and the cost of the communication system is increased. It becomes possible to aim for down and service improvement.

  Hereinafter, embodiments of the PON system, the station side device (OLT), and the subscriber side device (ONU) according to the present invention will be described in detail.

(First embodiment)
FIG. 1 is a diagram illustrating a system configuration example of a PON system 100 according to the first embodiment. FIG. 1 (a) shows a downlink, and FIG. 1 (b) shows an uplink, and shows examples of bands in each part.

  The PON system 100 is a PON system that uses 10G-EPON with a communication speed of 10 Gbps and GE-PON with a communication speed of 1 Gbps, like the PON system 900 of FIG. 10 described above.

  In FIG. 1, a PON system 100 includes a station side device (OLT) 101, a 10G-EPON subscriber side device (ONU) 102, a GE-PON subscriber side device (ONU) 103, and an optical splitter 104. , L2SW 105 and IP phone 106. The OLT 101 is connected to the L2SW 105 of the host communication apparatus connected to the host NW via the SNI via a 10 Gbps dedicated line for both upstream and downstream.

  The PON system 100 uses time division multiplexing (TDM) on the uplink from the ONUs 102 and 103 to the OLT 101 and uses wavelength division multiplexing (WDM) on the downlink from the OLT 101 to the ONUs 102 and 103. Here, for example, the upstream optical wavelength is 1.31 μm, the 10G-EPON downstream optical wavelength is 1.49 μm, and the GE-PON downstream optical wavelength is 1.57 μm, for example. This configuration is the same as that of the conventional PON system 900 described with reference to FIG. 10, but in the PON system 100 according to the first embodiment, a dedicated line by the second wavelength division multiplexing (WDM) is further provided on the downlink and the uplink. Provided. For example, in the downlink of FIG. 1A, in addition to the wavelength multiplexing of the 10G-EPON downlink and the GE-PON downlink, the OLT 101 and the IP phone 106 have different wavelengths (for example, around 1.4 μm). Up to 0.3 Gbps bandwidth dedicated downlink is multiplexed. As a result, the total bandwidth of the downlink from the OLT 101 to the ONUs 102 and 103 and the IP telephone 106 becomes 10 Gbps (8.7G + 1.0G + 0.3G), and the entire bandwidth of the downlink dedicated line from the L2SW 105 to the OLT 101 can be utilized. it can.

  On the other hand, for example, in the uplink of FIG. 1B, in addition to the time division multiplexing of the uplink of 10G-EPON and the uplink of GE-PON, IP telephones with different wavelengths (for example, around 1.65 μm) are used. An uplink dedicated line with a bandwidth of 0.3 Gbps from 106 to OLT 101 is multiplexed. As a result, the total bandwidth of the uplink from the ONUs 102 and 103 and the IP telephone 106 to the OLT 101 is 9 Gbps (8.7 G + 0.3 G), and approximately 90% of the bandwidth of the uplink dedicated line from the OLT 101 to the L2SW 105 is utilized. Can do.

  Here, the wavelength of the dedicated line for the IP phone 106 described above is an example, and other wavelength bands may be used. Since the communication speed of the IP telephone 106 is low, it can be considered that it can be sufficiently used by functions such as error correction even in a wavelength band near the performance limit of the optical fiber. Further, if the communication device is a low-speed communication device (for example, a control device or a monitoring device) other than the IP phone 106, the surplus bandwidth can be used similarly.

  As described above, the PON system 100 according to the present embodiment can be used for other communications such as the IP phone 106 by using the surplus bandwidth of the line between the OLT 101 and the L2SW 105 of the host communication apparatus. It becomes possible to aim for down and service improvement.

  Next, a configuration example of the OLT 101 that is a station side device of the PON system 100 will be described.

[Configuration of OLT 101]
FIG. 2 is a block diagram illustrating a configuration example of the OLT 101. In FIG. 2, the OLT 101 includes a WDM unit 201, a communication unit 202, a PON control unit 203, and a higher-level IF unit 204. The OLT 101 corresponds to a dual rate of 1 Gbps G-EPON and 10 Gbps 10GE-PON.

  The communication unit 202 includes an optical module 221 and a SERDES unit 222. The optical module 221 includes O / E conversion that converts an optical signal received from the ONU side into an electrical signal, and E / O conversion that converts an electrical signal input from the SERDES unit 222 into an optical signal. Further, the optical module 221 includes a 1G-EPON 1G transmission unit 231, a 10GE-PON 10G transmission unit 232, a 1G / 10G reception unit 233 corresponding to a dual rate of 1G-EPON and 10GE-PON, It comprises a 0.3G transmission unit 234 and a 0.3G reception unit 235 that constitute a 3G dedicated line. The SERDES unit 222 converts serial data input / output from / to the optical module 221 and parallel data input / output from / to the PON control unit 203.

  The WDM unit 201 performs wavelength multiplexing and wavelength separation on communication data with the ONU side. For example, the transmission signal to the ONU side and the reception signal from the ONU side are wavelength multiplexed and wavelength separated. For example, a 1G-EPON transmission signal output from the 1G transmission unit 231, a 10GE-PON transmission signal output from the 10G transmission unit 232, and a dedicated line transmission signal output from the 0.3G transmission unit 234 are wavelength-multiplexed. And transmit to the ONU side. Also, the WDM unit 201 separates the wavelength of the 1G / 10G time-division multiplexed dual rate received signal received from the ONU side and the 0.3G received signal received from the ONU side. Then, the WDM unit 201 outputs a 1G / 10G time division multiplexed reception signal to the 1G / 10G reception unit 233 of the optical module 221 and outputs a 0.3G reception signal to the 0.3G reception unit 235.

  The PON control unit 203 includes a frame transmission / reception unit 241, an ONU management unit 242, and a storage unit 243. The frame transmission / reception unit 241 receives a frame received from the ONU side output from the SERDES unit 222 of the communication unit 202 and outputs the frame to the upper line via the upper IF unit 204. Conversely, the frame transmission / reception unit 241 outputs the frame received from the upper line via the higher-level IF unit 204 to the SERDES unit 222. The frame transmission / reception unit 241 outputs the control frame to the ONU management unit 242 among the frames received from the ONU side, and outputs the data frame to the upper line. Alternatively, the control frame output from the ONU management unit 242 is transmitted to the ONU side via the SERDES unit 222 of the communication unit 202.

  Here, the ONU management unit 242 includes a control frame transmission / reception unit 251, a communication amount calculation unit 252, and a control unit 253. The control frame transmission / reception unit 251 receives and analyzes the control frame input from the frame transmission / reception unit 241. For example, if the received control frame is a control frame for a transmission request from the ONU, the transmission buffer capacity (the amount of user data scheduled to be transmitted accumulated in the ONU transmission buffer) included in the control frame is extracted and the communication amount is extracted. The result is output to the calculation unit 252. The data frame and the control frame received from the ONU include ONL-specific LLID (logical link ID) information assigned to each ONU by the ONU management unit 242 when the ONU is registered in the OLT. It is possible to determine from which ONU the received frame is transmitted.

  The communication amount calculation unit 252 includes the transmission buffer capacity input from the control frame transmission / reception unit 251, the communication speed of the ONU (determined from the LLID information) stored in the storage unit 243, and the upper level connected to the upper L2SW 105. The data transmission amount allocated to the ONU is calculated using the communication speed of the line. Here, the data transmission amount is information for time-division multiplexing transmission signals of a plurality of ONUs on the uplink, and is composed of data transmission start timing (data transmission start time) and data transmission duration time. As a result, the ONU transmits data for a specified time from a specified time, so that transmission data of a plurality of ONUs can be time-division multiplexed without colliding. The uplink communication speed of each ONU is acquired at the time of registration of the ONU and is stored in the storage unit 243 in association with the LLID information of each ONU.

  The control unit 253 also performs operations of the entire OLT 101 such as data input / output between the control frame transmission / reception unit 251 of the ONU management unit 242, the communication amount calculation unit 252, and the storage unit 243 and the frame transmission / reception unit 241 of the PON control unit 203. Control.

  As described above, the OLT 101 that is a station side device of the PON system 100 according to the present embodiment is configured, and constructs a PON line with the ONU side and transmits / receives a data frame between the ONU side and the upper side.

  Next, a configuration example of the ONU 102 will be described.

[Configuration of ONU 102]
FIG. 3 is a block diagram illustrating a configuration example of the ONU 102 corresponding to the 10GE-PON of FIG. 3, the ONU 102 includes a WDM unit 301, a communication unit 302, a PON control unit 303, and a user IF unit 304.

  The communication unit 302 includes an optical module 321 and a SERDES unit 322. The optical module 321 includes O / E conversion that converts an optical signal received from the OLT side into an electrical signal, and E / O conversion that converts an electrical signal input from the SERDES unit 322 into an optical signal. Further, the optical module 321 includes a 10GE-PON 10G transmission unit 331 and a 10GE-PON 10G reception unit 332. The SERDES unit 322 converts serial data input / output from / to the optical module 321 and parallel data input / output from / to the PON control unit 303.

  The WDM unit 301 performs wavelength multiplexing and wavelength separation on communication data with the OLT side. For example, the transmission signal to the OLT side output from the 10G transmission unit 331 and the reception signal from the OLT side to the 10G reception unit 332 are wavelength-multiplexed and wavelength-separated.

  The PON control unit 303 includes a frame transmission / reception unit 341, a control unit 342, and a transmission buffer 343. The frame transmission / reception unit 341 receives the frame received from the OLT output from the SERDES unit 322 of the communication unit 302 and outputs the frame to the user terminal via the UNI of the user IF unit 304. On the contrary, the frame transmission / reception unit 341 creates a data frame by adding the LLID information given from the control unit 342 to the transmission data stored in the transmission buffer 343 input from the user terminal via the user IF unit 304 and creates a SERDES unit. It outputs to 322.

  The frame transmission / reception unit 341 outputs the control frame to the control unit 342 among the frames received from the SERDES unit 322, and the received data is received only when the data frame matches its own LLID information given from the OLT side at the time of registration. And output to the user terminal side. Alternatively, the frame transmission / reception unit 341 transmits the control frame output from the control unit 342 to the OLT side via the communication unit 302.

  Here, the control unit 342 includes a control frame transmission / reception unit 351, a transmission buffer amount notification unit 352, and a transmission timing control unit 353. The control frame transmission / reception unit 351 receives and analyzes the control frame input from the frame transmission / reception unit 341. Alternatively, the transmission buffer amount notification unit 352 acquires the amount of data scheduled to be transmitted stored in the transmission buffer 343, creates a control frame for a transmission request in the control frame transmission / reception unit 351, and transmits the frame transmission / reception unit 341 and the communication unit. It transmits to the OLT side via 302. In this way, a control frame for a transmission request is created and transmitted to the OLT side. On the other hand, the ONU data transmission amount calculated on the OLT side is transmitted from the OLT side as a transmission permission control frame, as described above. If the control frame received by the frame transmission / reception unit 341 is a control frame that permits transmission from the OLT, the data transmission amount calculated by the OLT included in the control frame is output to the transmission timing control unit 353. Here, the data transmission amount is the data transmission start timing (data transmission start time) and the data transmission duration described above. Then, the transmission timing control unit 353 transmits the transmission data read from the transmission buffer 343 at the data transmission start time for the transmission duration time allocated to the OLT side via the frame transmission / reception unit 341.

  The control unit 342 also controls the operation of the PON control unit 303 such as the frame transmission / reception unit 341 and the transmission buffer 343 and the operation of the entire ONU 102.

  As described above, the ONU 102, which is a subscriber side device of the PON system 100 according to the present embodiment, transmits data for a specified time from a specified time, so that transmission data of a plurality of ONUs do not collide, and the OLT side Send and receive data frames.

  Next, a configuration example of the ONU 103 will be described.

[Configuration of ONU 103]
FIG. 4 is a block diagram illustrating a configuration example of the ONU 103 corresponding to 1GE-PON of FIG. In FIG. 4, the same reference numerals as those in FIG. 3 described above basically indicate blocks having the same functions. A block in which an alphabet a is added to a block having the same number is a block having the same basic function but different in some functions.

  4, the ONU 103 includes a WDM unit 301, a communication unit 302a, a PON control unit 303, and a user IF unit 304. Here, only a different part from FIG. 3 is demonstrated.

  The communication unit 302a includes an optical module 321a and a SERDES unit 322. The optical module 321a includes O / E conversion that converts an optical signal received from the OLT side into an electrical signal, and E / O conversion that converts an electrical signal input from the SERDES unit 322 into an optical signal. For example, the optical module 321a includes a 1G-EPON 1G transmission unit 331a and a 1G-EPON 1G reception unit 332a.

  The only difference from the ONU 102 in FIG. 3 is that the line speed of data transmitted and received with the OLT side is 1 Gbps, and other operations are the same. For example, the control unit 342 of the PON control unit 303 acquires the data amount scheduled to be transmitted stored in the transmission buffer 343, creates a control frame for a transmission request, and transmits it to the OLT side. On the other hand, upon receiving a transmission permission control frame from the OLT side, the control unit 342 refers to the data transmission amount (data transmission start timing (data transmission start time) and data transmission duration time) included in the control frame, The transmission data read from the transmission buffer 343 at the data transmission start time is transmitted through the frame transmission / reception unit 341 for the transmission duration allocated to the OLT side.

  Next, a configuration example of IP phone 106 will be described.

[Configuration of IP phone 106]
FIG. 5 is a block diagram showing a configuration example of the IP phone 106 corresponding to the 0.3 Gbps dedicated line in FIG. In FIG. 5, the same reference numerals as those in FIGS. 3 and 4 described above basically indicate blocks having the same functions. A block in which an alphabet b is added to a block having the same number is a block having the same basic function but different in some functions.

  In FIG. 5, the IP phone 106 includes a WDM unit 301, a communication unit 302b, a PON control unit 303b, a telephone IF unit 361, and a handset 362. Only portions different from those in FIGS. 3 and 4 will be described.

  The communication unit 302b includes an optical module 321b and a SERDES unit 322. The optical module 321b includes O / E conversion that converts an optical signal received from the OLT side into an electrical signal, and E / O conversion that converts an electrical signal input from the SERDES unit 322 into an optical signal. For example, the optical module 321b includes a 0.3G transmission unit 331b corresponding to a 0.3 Gbps dedicated line and a 0.3G reception unit 332b corresponding to a 0.3 Gbps dedicated line.

  The only difference between the ONU 102 in FIG. 3 and the ONU 103 in FIG. 4 is that the line speed of data transmitted / received to / from the OLT side is 0.3 Gbps, and the operations of the WDM unit 301, the communication unit 302b, and the PON control unit 303 are the same. is there.

  On the other hand, the PON control unit 303b includes a frame transmission / reception unit 341b and a control unit 342b. The frame transmission / reception unit 341b converts transmission data input from the telephone IF 361 into a transmission frame and outputs the transmission frame to the SERDES unit 322 of the communication unit 302b. Conversely, the received frame is input from the SERDES unit 322b, the received data is separated and output to the telephone IF unit 361.

  The control unit 342b controls the operation of the PON control unit 303b such as the frame transmission / reception unit 341b, the operation of the telephone IF unit 361, and the entire operation of the IP phone 106.

  The telephone IF unit 361 has a dial operation member, and transmits the input dial number to a higher-level IP telephone control server in a predetermined control format, thereby forming a line with the call destination. Then, the voice signal input from the handset 362 is converted into a transmission data frame having a predetermined format including a call destination address, output to the PON control unit 303b, and transmitted to the IP telephone control server via the OLT and a higher-level communication device. The Conversely, the telephone IF unit 361 converts the received data frame from the call destination input from the PON control unit 303b into a voice signal and outputs the voice signal to the handset 362. In this way, the IP phone 106 can establish a telephone line with the other party and make a call.

  In particular, in the PON system 100 according to the present embodiment, since a 0.3 Gbps dedicated line is wavelength-multiplexed with a wavelength different from 10GE-PON and 1G-EPON, the conventional 10GE-PON and 1G-EPON lines are affected. Never give. Accordingly, it is possible to effectively use 0.3 Gbps of the uplink and downlink bandwidth between the OLT 101 of FIG. 1 and the L2SW 105 of the host communication device. For example, in the case of FIG. 1A, the maximum downlink bandwidth from the OLT 101 to the ONU side is 10 Gbps, and the 10 Gbps downlink between the OLT 101 and the L2SW 105 of the higher-level communication device is used to the maximum. Can do. Even in the case of FIG. 1B, the maximum uplink bandwidth from the ONU side to the OLT 101 side is 9 Gbps, and the 10 Gbps uplink between the OLT 101 and the L2SW 105 of the host communication device is more effective than the conventional one. Can be used.

  As described above, the PON system 100 according to the present embodiment can be used for other communications such as the IP phone 106 by using the surplus bandwidth of the line between the OLT 101 and the L2SW 105 of the host communication apparatus. It becomes possible to aim for down and service improvement.

  Here, in the above description, a 0.3 Gbps dedicated line for the IP phone 106 is provided. However, a low-speed communication device other than the IP phone 106 (for example, a control device or a monitoring device) is also used. Is possible.

(Second Embodiment)
Next, the PON system, station apparatus, and subscriber apparatus according to the second embodiment will be described.

  In the first embodiment, the extra bandwidth of the line between the OLT 101 and the L2SW 105 of the higher-level communication device is effectively used by wavelength multiplexing a new dedicated line, but as described with reference to FIG. In the case of the uplink, there is still a problem that a surplus bandwidth of 1 Gbps is generated. Therefore, in the present embodiment, a PON system that can effectively use such surplus bandwidth will be described.

  FIG. 6A is a diagram illustrating a configuration example of the PON system 100c according to the present embodiment. In FIG. 6A, only one ONU 102 c is shown for easy understanding, but a plurality of ONUs are actually connected via the optical splitter 104.

  In FIG. 6A, the PON system 100c includes an OLT 101c, an ONU 102c, an optical splitter 104, and an L2SW 105 serving as a host communication device. The PON system 100c corresponds to the PON system 100 described in the first embodiment, and components having the same reference numerals as those in FIG. 1 basically indicate blocks having the same functions. A block in which the letter c is added to the same numbered block is a block having the same basic function but different in some functions.

  Here, a different part from the PON system 100 of FIG. 1 is demonstrated.

  In FIG. 6A, the ONU 102c compresses transmission data input from the user terminal and transmits the compressed data to the OLT 101c. Note that the upstream line from the ONU 102c to the OLT 101c is the same as FIG. 1B, and therefore has a maximum bandwidth of 8.7 Gbps. Therefore, for example, the ONU 102c can transmit 10-Gbps data to the OLT 101c by time division multiplexing by compressing the 10-Gbps data output from the user terminal to 8.7 Gbps, for example. Then, the OLT 101c decompresses the compressed data received from the ONU 102c, restores it to the original 10 Gbps band data, and outputs it to the 10 Gbps upper line of the L2SW 105. As a result, the OLT 101c can make maximum use of the bandwidth of the upper line.

  FIG. 6B shows a configuration example of the PON system 100c when a plurality of ONUs having the compression function described in FIG. 6A are connected. In FIG. 6B, the same reference numerals as those in FIG.

  In FIG. 6B, the ONUs 102c and 103c compress the transmission data input from the user terminal and transmit it to the OLT 101c. Note that the upstream line from the ONUs 102c and 103c to the OLT 101c is the same as FIG. 1B, and therefore has a maximum bandwidth of 8.7 Gbps.

  Here, for example, the ONU 102c compresses 6 Gbps data output from the user terminal to 5.5 Gbps. Similarly, the ONU 103c compresses 4 Gbps data output from the user terminal to 3.2 Gbps. Since the total bandwidth of the compressed data output from the ONUs 102c and 103c to the PON line is 8.7 Gbps, it can be transmitted by time division multiplexing up to the OLT 101c. The OLT 101c decompresses each compressed data received from the ONUs 102c and 103c, restores the original 6 Gbps band data and 4 Gbps band data, and outputs them to the 10 Gbps upper line of the L2SW 105. As a result, the OLT 101c can make maximum use of the bandwidth of the upper line.

  As described above, the PON system 100c according to the present embodiment compresses the transmission data of the subordinate ONUs 102c and 103c and transmits the compressed data to the OLT 101c so that no surplus bandwidth is generated in the upper line between the OLT 101c and the L2SW 105 of the upper communication apparatus. As a result, the substantial amount of transmission data can be increased. Thereby, it is possible to reduce the cost of the communication system and improve the service.

  Next, compression processing in the ONUs 102c and 103c and decompression processing in the OLT 101c will be described in detail. The basic configuration of the ONUs 102c and 103c is the same as the ONU 102 in FIG. 3 and the ONU 103 in FIG. 4 described in the first embodiment. Similarly, the basic configuration of the OLT 101c is the same as the OLT 101 of FIG. 2 described in the first embodiment.

[Configuration of ONUs 102c and 103c]
The basic configuration of the ONUs 102c and 103c is the same as the ONU 102 of FIG. 3 and the ONU 103 of FIG. 4 described in the first embodiment. What is different from the ONUs 102 and 103 is the configuration of the PON control unit 303 in FIGS. 3 and 4. A configuration example of the PON control unit 303c in the ONUs 102c and 103c is shown in FIG.

  In FIG. 7, the same reference numerals as those in FIGS. 3 and 4 basically indicate blocks having the same functions. A block in which the letter c is added to the same numbered block is a block having the same basic function but different in some functions.

  The PON control unit 303c includes a frame transmission / reception unit 341, a control unit 342c, a transmission buffer 343, and a compression unit 401. In FIG. 7, transmission data input from the user terminal side is temporarily stored in the transmission buffer 343. The transmission data stored in the transmission buffer 343 is transmitted to the OLT side via the frame transmission / reception unit 341 at the transmission timing (transmission start time and transmission duration time) assigned from the OLT side by the control unit 342c.

  The control unit 342c basically includes a control frame transmission / reception unit 351, a transmission buffer amount notification unit 352, and a transmission timing control unit 353. The operations of the control frame transmission / reception unit 351, the transmission buffer amount notification unit 352, and the transmission timing control unit 353 are as described with reference to FIG.

  The compression unit 401 compresses the transmission data stored in the transmission buffer 343 with a predetermined compression algorithm, replaces the compressed data (compressed data) with the transmission data before compression, and stores the data in the transmission buffer 343. The transmission buffer amount notification unit 352 notifies the OLT side of the data amount held in the transmission buffer 343 after compression.

  In this way, the ONUs 102c and 103c of the PON system 100c according to the present embodiment compress the transmission data input from the user terminal, and transmit the compressed data to the OLT side at the transmission timing assigned from the OLT side.

  Note that a flag indicating compressed data may be added as header information of a data frame when transmitting compressed data. As a result, it is possible to determine whether or not the data received on the OLT side is compressed data. When the data is compressed data, the data is decompressed. When the data is uncompressed data, the decompression process can be prevented.

  Furthermore, when using a plurality of compression algorithms depending on the type of data, information on the compression algorithm used for compression may be added to the compressed data frame. Alternatively, whether the ONU performs the compression process or the type of the compression algorithm may be notified to the OLT side in advance. In this case, there is an advantage that the same data frame as the conventional one can be used.

[Modification of ONUs 102c and 103c]
As described above, the PON system 100c that simply compresses transmission data and transmits it to the OLT side may be used, but there is a difference in compression rate depending on the type of transmission data. However, since the OLT side allocates a band in accordance with the amount of data scheduled to be transmitted (transmission buffer amount) stored in the transmission buffer 343, an ONU that transmits data with a low compression rate transmits an ONU that transmits data with a high compression rate. As a result, there arises a problem that the data transfer efficiency is lowered. Therefore, a modified example of the ONUs 102c and 103c for controlling the bandwidth allocated to each ONU according to the compression rate and the transmission buffer amount will be described.

  In FIG. 7, the control unit 342c of the PON control unit 303c is provided with a block compression rate notification unit 402 drawn with a dotted line. The compression rate notification unit 402 calculates a compression rate when the transmission data stored in the transmission buffer 343 is compressed by the compression unit 401 and notifies the OLT side of the compression rate. The notification of the compression rate may be included in the transmission request control frame created by the control frame transmission / reception unit 351 and transmitted to the OLT side. The control frame transmission / reception unit 351 may use a dedicated control frame for notifying the compression rate. May be generated and transmitted to the OLT side.

  As described above, the ONUs 102c and 103c in the present modification compress the transmission data input from the user terminal and notify the compression rate to the OLT side. On the OLT side, the bandwidth allocated to each ONU is calculated based on the compression rate (or compression rate and transmission buffer amount), and the bandwidth is allocated to each ONU so as not to be unfair due to the difference in compression rate. Then, the ONUs 102c and 103c transmit the compressed data to the OLT side at the transmission timing assigned from the OLT side. Note that the processing on the OLT side of the compression rate notified from the ONUs 102c and 103c will be described in detail in the following modification of the OLT 101c.

[Configuration of OLT 101c]
Next, the configuration of the OLT 101c will be described. The basic configuration of the OLT 101c is the same as the OLT 101 of FIG. 2 described in the first embodiment. What is different from the OLT 101 is the configuration of the PON control unit 203 in FIG. A configuration example of the PON control unit 203c in the OLT 101c is shown in FIG.

  In FIG. 8, the same reference numerals as those in FIG. 2 basically indicate blocks having the same function. A block in which the letter c is added to the same numbered block is a block having the same basic function but different in some functions.

  The PON control unit 203c includes a frame transmission / reception unit 241, an ONU management unit 242c, a storage unit 243, a buffer 451, and an expansion unit 452. In FIG. 8, received data input from the ONU side is temporarily stored in a buffer 451. Then, the data stored in the buffer 451 is read by the higher-order IF in FIG. 2 via the frame transmission / reception unit 241 and transmitted to the higher-order line according to the destination. On the other hand, data received from the higher-order line is converted into a PON system frame by the frame transmission / reception unit 241 and transmitted to the ONU side. At this time, the ONU management unit 242c stores LLID information corresponding to each ONU in the header of the frame. Note that the LLID information for each ONU is stored in the storage unit 243 when the ONU is registered, as described with reference to FIG.

  In this way, the OLT 101c transfers data received from each ONU to the upper line, and transfers data received from the upper line to each ONU. Here, the OLT 101c of the PON system 100c according to the present embodiment is provided with a decompression unit 452 for decompressing the compressed data received from the ONU side.

  Similarly to FIG. 2, the ONU management unit 242c includes a control frame transmission / reception unit 251, a communication amount calculation unit 252, a control unit 253c, and an expansion control unit 453. The operations of the control frame transmission / reception unit 251 and the traffic calculation unit 252 are the same as those of the PON control unit 203 in FIG. The control unit 253c is the same as the control regarding the control frame transmission / reception unit 251 and the communication amount calculation unit 252, but also controls the operations of the expansion control unit 453 and the expansion unit 452.

  The decompression control unit 453 uses the compressed data that is added to the header information of the data frame in accordance with the compression-related information notified from the ONU side (whether the ONU performs the compression process or the type of the compression algorithm). If the data frame received from each ONU temporarily stored in the buffer 451 is compressed data with reference to the flag indicating the presence or absence of the data, the decompression unit 452 performs decompression processing to buffer the decompressed data. Replace with compressed data 451.

  In this way, the ONU management unit 242c allows the received data temporarily received in the buffer 451 by the decompression control unit 453 even when the data received from each ONU is a mixture of compressed data and non-compressed data. Only compressed data that needs to be decompressed can be decompressed.

[Modification of OLT 101c]
As described above, the OLT 101c that simply decompresses the compressed data sent from the ONU side and transmits it to the upper side may be used. However, as described above, there is a difference in the compression rate depending on the type of transmission data. When ONUs that transmit data with a low compression rate and ONUs that transmit data with a high compression rate coexist, there arises a problem that bandwidth allocation becomes unfair. Therefore, a modified example of the OLT 101c for controlling the bandwidth allocated to each ONU according to the compression rate and the transmission buffer amount will be described. It is assumed that the OLT 101c in this modification constitutes the PON system 100c in combination with the above-described modification of the ONUs 102c and 103c.

  In FIG. 8, the control unit 242c of the PON control unit 203c is provided with a block compression rate acquisition unit 454 drawn by a dotted line. The compression rate acquisition unit 454 acquires the compression rate when the transmission data stored in the transmission buffer 343 of the ONUs 102 c and 103 c is compressed by the compression unit 401. The compression rate is acquired by being included in the control frame of the transmission request sent from the ONU side. Alternatively, a dedicated control frame for notifying the compression rate may be transmitted from the ONU side.

  When the control frame transmission / reception unit 251 of the ONU management unit 242c receives the control frame for the transmission request output from the frame transmission / reception unit 241 (or a dedicated control frame for notifying the compression rate), the control frame transmission / reception unit 251 outputs the control frame transmission / reception unit 251 to the compression rate acquisition unit 454. The compression rate acquisition unit 454 extracts the compression rate from these control frames and outputs the compression rate to the communication amount calculation unit 252.

  Here, in the description of FIG. 2, the communication amount calculation unit 252 transmits the data of each ONU according to the transmission buffer amount of each ONU, the uplink line speed of the PON system 100 c, and the line speed connected to the upper L2SW 105. Although the amount is calculated, the communication amount calculation unit 252c in the present modification performs a process of changing the data transmission amount once calculated according to the compression rate notified from the compression rate acquisition unit 454. For example, when the ONU 102c and the ONU 103c have the same uplink speed of 10 Gbps and the transmission buffer amounts notified from the ONUs 102c and 103c are the same, the data transmission amount allocated from the OLT 101c is the same, for example, 5 Gbps. Is assigned to each ONU.

  However, when the compression rates notified from the ONUs 102c and 103c are 80% and 20%, respectively, the traffic calculation unit 252c allocates a 2 Gbps bandwidth to the ONU 102c and allocates an 8 Gbps bandwidth to the ONU 103c. That is, each band is recalculated at the inverse ratio of the compression rate to the previously calculated band of 5 Gbps. As a result, a narrow band is allocated to the ONU 102c having the higher compression ratio and a wide band is allocated to the ONU 103c having the lower compression ratio, so that the data transfer efficiency between the ONU 102c and the ONU 103c becomes fair. That is, the bandwidths of the ONU 102c and the ONU 103c after expansion on the OLT 101c side are both 5 Gbps, and there is no surplus bandwidth in the 10 Gbps upper line of the L2SW 105 on the upper side from the OLT 101c.

  As described above, the OLT 101c in the present modification calculates the bandwidth to be assigned to each ONU based on the data compression rate notified from the ONU side, so that the bandwidth is assigned to each ONU so as not to be unfair due to the difference in the compression rate. Can do. As a result, the PON system 100c according to the present embodiment compresses transmission data of the subordinate ONUs 102c and 103c and transmits the compressed data to the OLT 101c so that no surplus bandwidth is generated in the upper line between the OLT 101c and the L2SW 105 of the upper communication apparatus. Therefore, the substantial amount of transmission data can be increased, and the cost of the communication system can be reduced and the service can be improved.

  As mentioned above, although the PON system, the station side apparatus, and the subscriber side apparatus according to the present invention have been described with reference to the embodiments, the present invention can be implemented in various other forms without departing from the spirit or main features thereof. Can do. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The present invention is defined by the claims, and the present invention is not limited to the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

100, 100c, 900 ... PON system 101, 101c, 901 ... Station side equipment (OLT)
102, 103, 102 c, 103 c, 902, 903... Subscriber side unit (ONU)
104, 904... Optical splitter 105, 905... L2SW
106: IP telephone 201, 301: WDM unit 202, 302, 302a, 302b ... communication unit 203, 203c, 303, 303b, 303c ... PON control unit 204 ... upper-level IF unit 221 , 321, 321 a, 321 b... Optical module 222, 322, 322 b... SERDES unit 231... 1 G transmission unit 232, 331, 331 a, 331 b. 234 ... 0.3G transmission unit 235 ... 0.3G reception unit 241,341,341b ... frame transmission / reception unit 242,242c ... ONU management unit 243 ... storage unit 251,351 ... Control frame transmission / reception units 252, 252 c... Traffic amount calculation units 253, 253 c, 342, 342 b, 342 c. .. User IF units 332, 332a, 332b... 10G reception unit 343... Transmission buffer 352... Transmission buffer amount notification unit 353... Transmission timing control unit 361. Handset 401 ... compression unit 402 ... compression rate notification unit 451 ... buffer 452 ... expansion unit 453 ... expansion control unit 454 ... compression rate acquisition unit

Claims (5)

In a PON system composed of a subscriber side device for connecting a user terminal and a station side device for connecting a plurality of the subscriber side devices via a PON line,
The subscriber side device is:
A transmission buffer for temporarily holding transmission data of the user terminal;
A data compression unit for compressing transmission data held in the transmission buffer;
A transmission request control frame including a transmission data amount of the transmission buffer is transmitted to the station side device; a transmission permission control frame including a data transmission start timing and a data transmission duration time is received from the station side device; A subscriber-side control unit that transmits the compressed data of the buffer, and
The station side device
A data decompression unit for decompressing the compressed data received from the subscriber side device;
Using the transmission data amount notified from each subscriber side device, the upstream PON line speed information of the subscriber side apparatus, and the upper line speed information, the upstream communication of the subscriber side apparatus A transmission permission control frame including the data transmission start timing and the data transmission continuation time, and a data transmission start timing and a data transmission continuation time to the PON line to which the subscriber side device is connected. the transmits to the subscriber unit, possess a station side control unit that transmits the data frame to the data decompression section is extended to the upper side line,
The subscriber-side control unit of the subscriber-side device, the data compression unit includes a data compression rate for the transmission data of the transmission buffer included in the transmission request control frame, and transmits to the station-side device,
The station-side control unit of the station-side device compares a plurality of data compression rates included in the transmission request control frames received from the plurality of subscriber-side devices, and a subscriber having a relatively low compression rate The upstream communication volume of each subscriber-side device is calculated so that the upstream bandwidth of the PON line is widely allocated to the side device, and the data transmission start timing and data transmission to the PON line to which each subscriber-side device is connected A PON system characterized by obtaining a duration time . In the subscriber side device that is accommodated in the PON system station side device by the PON line and transmits the data of the user terminal,
A transmission buffer for temporarily holding transmission data of the user terminal;
A data compression unit for compressing transmission data held in the transmission buffer;
A transmission request control frame including a transmission data amount of the transmission buffer is transmitted to the station side device; a transmission permission control frame including a data transmission start timing and a data transmission duration time is received from the station side device; And a subscriber-side control unit that transmits the compressed data of the buffer ,
The subscriber side device, wherein the data compression unit includes the data compression rate for the transmission data of the transmission buffer in the transmission request control frame and transmits the data to the station side device. In the station side device of the PON system that accommodates a plurality of subscriber side devices to which user terminals are connected by a PON line,
A data decompression unit for decompressing the compressed data received from the subscriber side device;
Using the transmission data amount notified from each subscriber side device by a transmission request control frame , the upstream PON line rate information of the subscriber side device, and the higher side line rate information, the subscriber side device And calculating the data transmission start timing and data transmission duration time to the PON line to which the subscriber side apparatus is connected, and calculating the data transmission start timing and the data transmission duration time. A transmission permission control frame including the station side control unit for transmitting the data frame expanded by the data expansion unit to an upper line ,
The station-side control unit compares a plurality of data compression rates included in the transmission request control frames received from the plurality of subscriber-side devices, and sends the PON to a subscriber-side device having a relatively low compression rate. The amount of communication in the uplink direction of each subscriber side device is calculated so as to widely allocate the uplink bandwidth of the line, and the data transmission start timing and data transmission duration time to the PON line to which each subscriber side device is connected are obtained. The station side device characterized by the above-mentioned. The PON system according to claim 1 ,
Providing a dedicated subscriber terminal different from the subscriber side device connected to the station side device via a dedicated line wavelength-multiplexed to the PON line in a band different from the PON line;
In the station side device,
A demultiplexing unit that multiplexes and demultiplexes data transmitted and received between the plurality of subscriber-side devices and the higher-level line;
A subscriber unit management unit for managing the plurality of subscriber units accommodated for each station unit;
A communication unit for communicating with the dedicated subscriber terminal via a dedicated line wavelength-multiplexed with the PON line in a band different from the PON line;
The demultiplexing unit multiplexes data received from the dedicated subscriber terminal by the communication unit with data received from the plurality of subscriber side devices and transmits the multiplexed data to the upper line, and receives data received from the upper line. A PON system, wherein the separated data for the dedicated subscriber terminal is transmitted to the dedicated subscriber terminal via the communication unit. In the PON system according to claim 4 ,
The PON system, wherein the dedicated subscriber terminal is an IP phone.

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