JP4829805B2 - Station side device and subscriber side device - Google Patents

Description

  The present invention relates to a station apparatus installed on a broadcasting station side and a subscriber apparatus installed on a network subscriber side.

  Conventionally, a passive optical subscriber is a method for economically configuring an optical subscriber access system, which is a system using optical communication with a broadcast station as an access point, by a large number of subscribers who have contracts with broadcast stations, etc. A network (PON: Passive Optical Network) is being studied. As one of the passive optical network (PON), E-PON using Ethernet (registered trademark) technology has been standardized as IEEE 802.3ah-2004 and put into practical use.

  This E-PON will be described with reference to FIG. As shown in FIG. 5, the E-PON system 101 includes a station side device OLT (Optical Line Terminal) 103 and a large number (1,..., N) of subscriber side devices ONU (Optical Network Unit) 105. One optical fiber connected to the station side apparatus OLT 103 is branched halfway and connected to a number of subscriber side apparatuses ONUs 105. In other words, in the E-PON system 101, the station side apparatus OLT 103 and a large number of subscriber side apparatuses ONUs 105 are connected in a point-to-multipoint (P2MP) connection form. In general, a signal from the station-side device OLT 103 to the subscriber-side device ONU 105 is referred to as a downstream signal (optical signal), and a signal from the subscriber-side device ONU 105 to the station-side device OLT 103 is referred to as an upstream signal ( Optical signal).

  The station-side device OLT 103 is installed in the broadcasting station, connected to an external communication network such as the Internet via a router, and transmits an optical signal to the subscriber-side device ONU 105, and includes an OLT function processing unit 107, An optical transmission unit 109, an optical reception unit 111, and a WDM (Wavelength Division Multiplexing) coupler 113 are provided.

The OLT function processing unit 107 performs processing on a MAC (Media Access Control) layer of an optical signal. The MAC layer processing includes MAC frame processing described later, MAC control for discovering and registering a new subscriber-side device ONU 105, and processing for logically emulating a point-to-point (P2P) connection on the P2MP network. include. The optical transmission unit 109 and the optical reception unit 111 perform physical layer processing of an optical signal. The processing of the physical layer includes 8B / 10B conversion, photoelectric conversion, and the like. The WDM coupler 113 combines and separates an upstream signal (wavelength, λ ₂ ) and a downstream signal (wavelength, λ ₁ ).

  The subscriber-side device ONU 105 is installed in each subscriber's house, is connected to a PC on the HN (home network) via the HGW (home gateway), and receives an optical signal transmitted from the station-side device OLT 103 The WDM coupler 115, the optical receiver 117, the optical transmitter 119, and the ONU function processor 121 are provided.

The WDM coupler 115 combines and separates a downstream signal (wavelength, λ ₁ ) and an upstream signal (wavelength, λ ₂ ). The optical receiving unit 117 and the optical transmitting unit 119 perform processing on the physical layer of the optical signal. The ONU function processing unit 121 performs processing on the MAC layer of the optical signal.

  In the E-PON system 101, the station side apparatus OLT 103 gives a permission signal (access information) to each subscriber side apparatus ONU 105 in advance by a downstream signal, and the subscriber side apparatus ONU 105 In accordance with the content of the signal, an upstream signal is transmitted to the station side device OLT 103. This permission signal is generated by performing control in the station side apparatus OLT 103 in response to a request from the subscriber side apparatus ONU 105. Thereby, in the E-PON system 101, it becomes possible to assign an optical signal of an arbitrary band to each subscriber-side apparatus ONU 105.

  By doing so, the station side apparatus OLT 103 includes and outputs the optical signals to all the subscriber side apparatuses ONUs 105, and each subscriber side apparatus 105 is required from the received optical signals. Select and obtain the correct optical signal.

  In the E-PON system 101, the OLT function processing unit 107 of the station-side apparatus OLT 103 uses the identifier called LLID (Logical Link IDentifier) for the MAC layer processing (P2P emulation) of the optical signal, This is done as described below.

  First, LLID will be described with reference to FIG. This LLID is not included in the normal MAC frame (transmission frame) as shown in FIG. 6A, but is included in the preamble of the MAC frame in the PON section as shown in FIG. 6B. Contained. The value of this LLID is determined by the station side apparatus OLT 103 when the subscriber side apparatus ONU 105 is registered.

  In this case, the station side device OLT 103 determines the LLID so that no duplication occurs in the subscriber side device ONU 105 connected by an optical fiber, and transmits the determined value to the subscriber side device ONU 105 (in notification). ing). Incidentally, there is an operation in which a plurality of LLIDs are assigned to one subscriber-side apparatus ONU 105 for each service to be provided.

  Then, for each MAC frame, the station side apparatus OLT 103 determines which MAC frame is to be transmitted to which subscriber side apparatus ONU 105, and transmits the LLID for the subscriber side apparatus ONU 105 to be transmitted as a downlink signal to the MAC frame. Is embedded in the PON section (becomes the MAC frame of the PON section described above).

  Then, the subscriber side device ONU 105 takes in the MAC frame of the PON section including the LLID assigned to itself or the MAC frames addressed to all the subscriber side devices ONU 105 in the received MAC frame, Discard other MAC frames.

  Then, the subscriber unit ONU 105 embeds the LLID assigned to itself in the preamble of the MAC frame and sends it to the PON section. Further, the station side device OLT 103 receives the MAC frame transmitted from the subscriber side device ONU 105 in the PON section, and determines which of the subscriber side devices ONU 105 is the MAC frame transmitted by the LLID of the received MAC frame. to decide. By such processing, the E-PON system 101 performs processing of the optical signal MAC layer (P2P emulation), and logically realizes P2P connection.

  By the way, there has been a demand for providing a service such as distribution of a broadcast type video signal using an optical subscriber access system (a type in which the same signal is transmitted to all subscribers of the access system). In order to realize such a requirement, a pilot experiment in which a video signal is distributed and transmitted using a wavelength different from the wavelength used in communication has already been conducted in 1994 (The Institute of Electrical Engineers of Japan, Vol. 1995). -C, No. 6, pp. 756-767), which is currently in practical use.

  Here, a conventional PON system to which a broadcast type video distribution apparatus is added will be described with reference to FIG. The PON system 131 is obtained by adding a V-OLT 133 and a WDM coupler 135 to the station side device OLT 103 of the E-PON system 101 shown in FIG. 5 and a V-ONU 137 and a WDM coupler 139 to the subscriber side device ONU 105. .

V-OLT133 is a transmitter for optical transmission of the video signal for video distribution, and outputs the video signal as an optical signal of wavelength λ _3, V-ONU137 a video signal which is optically transmitted from the V-OLT133 It is a receiving device that receives and outputs. The WDM coupler 135 and the WDM coupler 139 combine / separate optical signals of wavelengths λ1 and λ2 used for communication and optical signals of wavelength λ3 used for video distribution. Also, with the same configuration as the configuration shown in FIG. 7, another optical fiber laid on the same path without using wavelength multiplexing is used for broadcast-type video distribution, and communication is performed using two optical fibers. Systems that provide type services and broadcast type services have also been put into practical use.

  In addition, as a video signal, it has been common so far that a modulated wave (a signal that has been AM or FM modulated with analog video or a signal that has been digitally modulated with MPEG-2TS, etc.) is frequency-multiplexed. However, a method of transmitting as a baseband digital signal in the format of MPEG-2TS over IP (or MPEG-2TS over Ethernet (registered trademark)) is also being studied (Video Media Technical Report, Vol. 30, No. 40, pp. .25-28).

  Note that, for this broadcast type service such as video distribution performed using another transmission device and reception device such as the V-OLT 133 and V-ONU 137 as in the PON system 131, the same IP as the communication type service is used. If it is performed in the format or the Ethernet (registered trademark) format, it is desired to use the surplus bandwidth of the broadcast type service in the communication type service and expand the bandwidth of the communication type service.

For example, in Patent Documents 1 and 2, a transmission system that performs bidirectional communication is added as a service in which a wideband transmission system that includes only independent downlink signals is added, and the downlink signals are increased in capacity. A method utilizing a broadband transmission system is disclosed.
JP 2000-101621 A JP 2002-232476 A

  However, these methods disclosed in Patent Documents 1 and 2 do not describe any contrivance for using the surplus bandwidth of the broadcast type service in the communication type service, but the signal of the added wideband transmission system. However, there is a problem that it is a broadcast type system that reaches all the subscriber side terminals, and does not coexist with a communication type service in which individual subscriber side terminals are logically distinguished.

  In addition, in order to logically distinguish individual subscriber side terminals in the added broadband transmission system, for example, LLID information managed on the conventional PON system side is passed to the added broadband transmission system, It is assumed that a destination is confirmed and a LLID is added to a signal (for each frame) transmitted on the broadband transmission system side, but the configuration on the added broadband transmission system side becomes complicated due to management of LLID information and the like. There is a problem that it ends up.

  Furthermore, there has been a demand for the subscriber side terminal to expand the downlink band including enjoying other services in addition to the communication type service.

  Therefore, in the present invention, in order to solve the above-described problem and add another service in the system based on the communication type service, the subscriber side, the terminal that supports only the communication type service, When terminals compatible with both the service and the communication-type service coexist, the communication-type service and other services coexist without complicating the configuration of the terminal that supports only the communication-type service. Therefore, an object of the present invention is to provide a station-side device and a subscriber-side device that can expand the downlink band for terminals that support both other services and communication-type services.

  In order to solve the above problem, the station apparatus according to claim 1 is a station apparatus in which at least one of a plurality of transmission units transmits a signal for a bidirectional communication service, and includes an identification information receiving unit and a surplus unit. A bandwidth acquisition unit, a label addition unit, a distribution unit, and a control unit, wherein the plurality of transmission units transmit a part of the signals for the bidirectional communication service distributed by the distribution unit. It comprises transmission means and transmission means for transmitting signals for bidirectional communication service other than the part of the signals distributed by the distribution means.

  According to such a configuration, the station side apparatus receives the identification information indicating the receivable signal transmitted from the receiving apparatus capable of receiving at least the signal for the bidirectional communication service by the identification information receiving unit. Subsequently, the station side apparatus detects the surplus band of a transmission unit other than the transmission unit that transmits the signal for the bidirectional communication service or sets a predetermined surplus band by the surplus band acquisition unit.

  Then, the station side device adds a label having at least a different value for each receiving device to the frame of the bidirectional communication service signal by the label adding unit based on the identification information received by the identification information receiving unit. The station side device uses the sorting unit to add a part of the bidirectional communication service signal to which a label having a predetermined value is added among the labels added by the label adding unit, Distribute signals for two-way communication service. Then, the station side device controls the output of the distributing means so that a part of the signal for the bidirectional communication service to which the label having a predetermined value is added in the surplus band.

  The station-side device according to claim 2 is a station-side device according to claim 1, wherein a counter representing the order of the frames is provided for the bidirectional communication service signal to which the label having the predetermined value is added. , And a counter adding means for adding to each frame.

  According to such a configuration, the station side device adds a counter to each frame for the signal for bidirectional communication service to which a label having a predetermined value is added by the counter adding means, so that the transmission side or the receiving side Thus, even if the frame order is changed during analysis, the signal can be accurately reproduced based on the counter.

  The station side device according to claim 3 is the station side device according to claim 1 or 2, further comprising a multiplexing means and a signal speed detecting means, wherein the surplus bandwidth acquisition means is the bidirectional communication service. The excess band is detected by obtaining a difference between a band of a transmission unit that transmits a part of the signal for use and a band occupied according to the signal speed detected by the signal speed detection unit. To do.

  According to such a configuration, the station side device multiplexes a part of the signals for the bidirectional communication service distributed by the distribution unit and the signal for the broadcast service by the multiplexing unit. Further, the station side device detects the signal speed of the signal for the broadcast service by the signal detection means.

  The subscriber-side device according to claim 4, wherein the subscriber-side device receives a bidirectional communication service signal or a plurality of downlink signals including at least the bidirectional communication service signal, and includes identification information transmitting means. A receiving means, a bidirectional communication service signal receiving means, a filtering means, and a multiplexing means.

  According to this configuration, the subscriber side apparatus transmits identification information indicating that a plurality of downlink signals can be received by the identification information transmitting unit. Further, the subscriber side device receives a part of the signal for the bidirectional communication service or a plurality of downlink signals by the receiving means. Then, the subscriber side apparatus receives signals for bidirectional communication service other than a part of the signals by means of the bidirectional communication service signal receiving means.

  Then, the subscriber-side device performs filtering on the bidirectional communication service signal received by the receiving unit and the bidirectional communication service signal reception unit, and each frame of the bidirectional communication service signal is filtered by the filtering unit. The information of the preamble part of the communication device is extracted, and the signal for bidirectional communication service transmitted to the own device is passed. Then, the subscriber side apparatus multiplexes the bidirectional communication service signal passed by the filtering means by the multiplexing means.

  A subscriber-side device according to a fifth aspect is the subscriber-side device according to the fourth aspect, further comprising a control unit.

  According to such a configuration, the subscriber side apparatus adjusts the order of the signals for the bidirectional communication service multiplexed by the multiplexing means based on the counter indicating the order of the frames included in the preamble section by the control means. To do.

  A subscriber-side device according to a sixth aspect is the subscriber-side device according to the fourth or fifth aspect, further comprising a sorting unit.

  According to such a configuration, the subscriber-side device distributes the bidirectional communication service signal and other signals by the distributing unit when a plurality of downlink signals are received by the receiving unit.

  According to the first aspect of the present invention, since a part of the signals for the bidirectional communication service is accommodated in the surplus band, the configuration of the communication type service (the signal for the bidirectional communication service is The communication service and other services can coexist without complicating the transmission configuration. Even if there is a receiving device that can receive only communication-type services on the receiving side, the communication device continues to communicate without complicating the configuration of the receiving device (without adding another configuration). You can enjoy a type of service.

  According to the second and fifth aspects of the present invention, by adding a counter to each frame, even if the order of frames is changed during transmission or analysis on the reception side on the side receiving each signal, the counter The signal can be accurately reproduced based on the above.

  According to the third aspect of the present invention, the broadcast type service and the two-way communication service can coexist by utilizing the surplus bandwidth of the signal for the broadcast type service.

  According to the fourth aspect of the present invention, the multiplexing order is adjusted based on the information of the preamble part extracted from the bidirectional communication service signal, and the other service signals are output as they are. Therefore, the communication service and other services can coexist without complicating the configuration of the communication service, and the downlink bandwidth can be expanded.

  According to the invention described in claim 6, the bidirectional communication service and the other service coexist by distributing the signal for the bidirectional communication service and the other signal based on a label having a predetermined value. Can be made.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
Here, regarding the E-PON system S including the station side device and the subscriber side device, first, the configuration and operation of the station side device will be described, and the configuration and operation of the subscriber side device will be described.

  FIG. 1 is a block diagram of the E-PON system S. As shown in FIG. 1, the E-PON system S transmits and receives signals for broadcast-type services (for other services) and signals for bidirectional communication services. The station-side device 1 and a plurality of subscribers It is comprised from the side apparatus 3, and these are connected by the optical fiber. The description of the E-PON system S is based on a conventional ONU (see FIG. 4) in addition to a plurality of subscriber side devices 3 as a receiving side device that receives a broadcast service signal and a bidirectional communication service signal. (Not shown) is assumed to be mixed. In this E-PON system S, for example, when a 10 Gbps transmission device is newly added in addition to a conventional transmission device for 1 Gbps ONU, only a signal for bidirectional communication service (for broadcast service ( There is also a case of transmission without (for other services).

  In this embodiment, the E-PON system S is 1.55 μm for a broadcast service signal, 1.49 μm for a downstream signal for a bidirectional communication service, and 1 for an upstream signal for a bidirectional communication service. It uses a wavelength of 3 μm and handles 3 wavelength multiplexed signals. The wavelength arrangement of the three-wavelength multiplexed signal is ITU-T GG. 983. The broadcast service signals are all made up of the same signal toward the receiving-side subscriber device 3, and the downlink signal and the uplink signal for the bidirectional communication service are made up of different signals. Has been.

(Configuration of station side device)
The station-side device 1 is installed on the broadcast station side and transmits a signal for a broadcast type service and a signal for a two-way communication service, which are optical signals, and includes an identification information receiving means 5, a signal speed detecting means 7, , Control means (including surplus bandwidth acquisition means) 9, OLT function processing means (label addition means) 11, distribution means 13, multiplexing means 15, multiplexed signal transmission means (transmission means) 17, delay Means 19, bidirectional communication service signal transmission means 21, link aggregation processing means 23, and connection means 25 are provided.

  The identification information receiving means 5 receives an optical signal (identification information transmitted from each subscriber side device 3) having an output level conforming to the standard of conventional E-PON (for example, 1000BASE-PX20). The identification information transmitted from the subscriber side device 3 is transmitted at the time of initial registration, and this initial registration is automatically performed when the subscriber side device 3 is connected to an optical fiber. The identification information receiving means 5 receives the identification information via the connection means 23. However, when the subscriber side apparatus 3 transmits the identification information via a general network, the link described later The identification information may be received via the aggregation processing means 23.

  The initial registration method is almost the same as the method defined in the conventional E-PON (for example, detailed description in Chapter 64, Section 3 of IEEE 802.3ah-2004). This is done by sending a register request signal (Register_Request signal) when connected to an optical fiber. This register request signal has a flag area (Flags area). In the conventional E-PON, when the value of this flag area is 0x01, it indicates a registration request, and when it is 0x03, it indicates a deregistration request. Other values are ignored in a conventional OLT (not shown).

  Therefore, the station side apparatus 1 indicates a registration request when the value of the flag area of the register request signal transmitted from the subscriber side apparatus 3 is, for example, 0x05, and indicates a deregistration request when the value is 0x07. It is said.

  That is, the identification information is represented by the value of the flag area of the register request signal. Specifically, when the value of the flag area of the register request signal is 0x01, the receiving device on the receiving side indicates a conventional ONU, This indicates that only the signal for the communication service can be received. When the value of the flag area of the register request signal is 0x05, the receiving device on the receiving side indicates the subscriber side device 3 and receives both the broadcast service signal and the bidirectional communication service signal. It will show what is possible.

  The signal speed detection means 7 detects the signal speed (transmission speed) of a broadcast service signal. The signal for the broadcast service is in the MPEG-2 TS over IP over Ethernet (registered trademark) format. The signal speed detected here indicates the rate of the MAC frame included in the broadcast service signal. The signal speed (MAC frame rate) detected by the signal speed detection means 7 is output to the control means 9.

  The control means 9 includes the signal speed (the MAC frame rate included in the broadcast service signal) detected by the signal speed detection means 7 and the OLT function processing means 11 included in the bidirectional communication service signal. Based on the presence / absence of a label (LLID) having a predetermined value added to the preamble of the MAC frame, the distribution unit 13 controls the distribution.

  The control of the distribution means 13 by the control means 9 is a label having a predetermined value added to the preamble of the MAC frame included in the bidirectional communication service signal output from the OLT function processing means 11. The presence or absence of (LLID), that is, whether the receiving side device is (1) all the subscriber side devices 3 or (2) whether or not conventional ONUs are mixed is different.

  (1) When all the receiving side devices are the subscriber side devices 3, the signal speed detected by the signal speed detecting means 7 is a (the MAC frame rate is a), Since the rates of the communication service signal transmission unit 21 and the multiplexed signal transmission unit 17 are 1 Gbps, a system (multiplexing unit 15, multiplexing with a broadcast service signal at a ratio of (1 Gbps-a) to 1 Gbps The multiplexed signal transmission means 17 and the connection means 25) and the system (delay means 19, the bidirectional communication service signal transmission means 21 and the connection means 25) that output the signals as they are for the bidirectional communication service are distributed to two systems. Thus, the control means 9 controls the distribution means 13. In this case, the surplus bandwidth of the broadcast service signal is a bandwidth of 1 Gbps-a.

  (2) When a conventional ONU is mixed in the receiving device, the signal speed detected by the signal speed detection means 7 is set to a (the MAC frame rate is set to a), and a predetermined value is set. For the MAC frame to which the LLID has been added, only the amount (part of the signal) corresponding to the rate of 1 Gbps-a is distributed to the system to be multiplexed with the broadcast service signal, and the remaining amount is bidirectionally communicated. The control unit 9 controls the distribution unit 13 so as to distribute to a system that outputs the signal for service as it is. In this case, the surplus bandwidth of the broadcast service signal is a bandwidth of 1 Gbps-a.

  In the case of (2), a frame with a LLID (label having a value other than a predetermined value) for a conventional ONU (for all receiving-side devices) is added as a signal for a bidirectional communication service. The control means 9 controls the distribution means 13 so as to distribute to the output system as it is.

  Further, in the control of the distribution means 13 by the control means 9, the signals received by all the receiving side devices such as the signals necessary for the initial registration of the subscriber side device 3 are output as they are as the signals for the bidirectional communication service. It is distributed to the system to do.

  Further, in the control of the distribution unit 13 by the control unit 9, the distribution amount distributed by the distribution unit 13 is adjusted according to the storage capacity (buffer amount) of a buffer (not shown) provided in the multiplexing unit 15 described later. The data amount of the broadcast service signal stored in the buffer may not exceed a threshold (storage capacity or less) (a broken line from the multiplexing unit 15 to the control unit 9 in FIG. 1).

  Furthermore, the control means 9 has a function of grasping the band amount that can be distributed to the multiplexing means 15 by the distribution means 13 based on the signal speed (transmission speed) of the broadcast service signal detected by the signal speed detection means 7. Have.

  For example, if the output rate of the multiplexing unit 15 is 1 Gbps and the rate a of the broadcast service signal input to the multiplexing unit 15 is 600 Mbps, the control unit 9 distributes from the OLT function processing unit 11 to the distribution unit 13. 400 Mbps (= 1G-600 Mbps) of the signal rate for the bidirectional communication service output to is multiplexed to the multiplexing means 15 side.

  Then, the control unit 9 outputs the bandwidth amount (400 Mbps in this case) that can be distributed to the multiplexing unit 15 to the distribution unit 13.

  The OLT function processing unit 11 performs processing of the MAC layer of the bidirectional communication service signal based on the identification information received by the control information receiving unit 5, and is included in the bidirectional communication service signal. An LLID (label) and a counter indicating the order of frames for each LLID are added to the preamble of the MAC frame being output to the distribution means 13.

  That is, in this OLT function processing means 11, the receiving device on the receiving side is the subscriber side device 3 based on the identification information (as illustrated, the value of the flag area of the register request signal is 0x05). When both the signal and the signal for the bidirectional communication service can be received, the MAC included in the signal for the bidirectional communication service is transmitted to the subscriber side device 3 as a multiplexed signal (details will be described later). A LLID (label) and a counter indicating the order of frames for each LLID are added to the preamble of the frame.

  Further, the OLT function processing means 11 uses the signal speed detection means 7 because the rate of the link aggregation processing means 23 to be described later is 2 Gbps so that the buffer (not shown) overflows after the distribution means 13. When the detected signal speed is a, control is performed so that the downstream signal band for bidirectional communication service is 2 Gbps-a.

  In other words, the OLT function processing unit 11 processes a registration acceptance request and an upstream signal transmission request from the receiving side device, and checks the MAC address of the bidirectional communication service signal input from the link aggregation processing unit 23. Thus, a label (LLID) is added according to the destination of the receiving apparatus, and the MAC frame is output to the distribution means 13.

  Here, the MAC frame will be described with reference to FIG. As shown in FIG. 2A, a normal MAC frame includes an 8-byte preamble, a 6-byte destination address, a 6-byte transmission source address, a 2-byte Type / Length, and fixed-length or arbitrary-length byte data ( User data) and 4 byte FCS. As shown in FIG. 2B, the PON section MAC frame to which the LLID (label) and a counter indicating the order of the frames for each LLID are added, the 2-byte reservation in the description order of the 8-byte preamble, and the SLD of 1 byte. (Start of LLID Delimiter), a 1-byte reservation, a counter representing the order of frames for each 1-byte LLID, a 2-byte LLID, and a 1-byte CRC (Cyclic Redundancy Check).

  By adding a counter indicating the order of frames for each 1-byte LLID to the front of the LLID, the subscriber-side device 3 (see FIG. 1) that has received the bidirectional communication service signal uses the LLID based on the counter. It is possible to count up in units of frames, and by arranging the frames of the signal for bidirectional communication service, the order of the frames is not changed (when the frames arrive at the receiving side, they are arranged in the order of arrival). To prevent the original order from changing.) In this case, since the conventional subscriber-side device ONU (not shown) may not be able to receive if there is a counter in the preamble of the MAC frame, the MAC frame addressed to the conventional subscriber-side device ONU, A counter is not added to the MAC frames addressed to all receiving devices (conventional ONU and subscriber device 3).

  Also, in a MAC frame to which a 1-byte counter is added, the SLD value is changed (the SLD value is set as a special value) compared to the conventional PON section MAC frame (see FIG. 6). ) In the subscriber side device 3, it can be determined whether or not a counter is added. Returning to FIG.

  The distributing unit 13 has a MAC frame that is a part of the signal for the bidirectional communication service to which the LLID (label) having a predetermined value and a counter are added by the OLT function processing unit 11 and a value other than the predetermined value. A system that multiplexes a MAC frame of a signal for a bidirectional communication service to which a LLID (label) is added, with a signal for a broadcast-type service based on control by the control means 9, and a signal for a bidirectional communication service The system is divided into two systems, that is, the system that outputs as it is.

The predetermined value may be any value as long as it is determined on the transmission side so that it can be identified on the reception side.
Further, the distribution means 13 can individually set a ratio (for example, an arbitrary fixed value) between an LLID having a predetermined value and an LLID having a value other than the predetermined value by a signal transmitted in advance. .

  In this embodiment, the distribution means 13 distributes the signal for bidirectional communication service according to a set fixed value ratio (distribution ratio) M: N (M ≦ N, where M and N are integers). When the signal for bidirectional communication service is viewed in units of (M + N) packets, the [(M + N) × k / M] (k: 1 to M, [] represents the nearest integer) packet The remaining packets are distributed to the M side.

  Further, the distribution unit 13 has a function of calculating a ratio of a fixed value based on the bandwidth amount when a bandwidth amount that can be distributed is output from the control unit 9 to the multiplexing unit 15.

  For example, the signal rate for the broadcast type service detected by the signal speed detection means 7 is a, the output rate of the multiplexing means 15 is 1 Gbps (1000 Mbps), and X conventional ONUs (not shown) are connected. When the number of subscriber side devices 3 is Y and the upper limit of the downstream bandwidth addressed to a conventional ONU (not shown) is 1 Gbps / (X + Y), the downstream bandwidth addressed to the subscriber side device 3 The upper limit is (1 Gbps / (X + Y) + (1000−a) Mbps / Y), and the fixed value ratio M: N is calculated as (1 Gbps / (X + Y)): ((1000−a) Mbps / Y). Can do.

  The multiplexing unit 15 multiplexes the remaining signal of the bidirectional communication service signal output from the distribution unit 13 and the broadcast service signal, and transmits the multiplexed signal to the multiplexed signal. This is output to the means 17. As described above, the MAC frame included in the bidirectional communication service signal output from the distribution unit 13 is a MAC frame to which LLID is added (described), and is used for a broadcast service. The MAC frame included in the signal is a normal MAC frame. Each of these MAC frames input to the multiplexing means 15 is, for example, in the form of GMII (Gigabit Media Independent Interface), multiplexed for each preamble, and sent to the multiplexed signal transmission means 17 in the same GMII format. Is output.

  The multiplexed signal transmitting means 17 transmits the multiplexed signal to the subscriber side device 3 by outputting the multiplexed signal output from the multiplexing means 15 to the connecting means 25 connected to the optical fiber. It is.

  The delay means 19 is composed of a general buffer, and delays the bidirectional communication service signal output from the distribution means 13 to multiplex with the broadcast service signal, and the bidirectional communication service. This adjusts the delay time of the two systems with the system that outputs the signal as it is.

  These two systems of signals are received and collected by the subscriber-side device 3 on the receiving side, but the two systems have different delay times, so that the OLT function processing means 11 In some cases, the order of frames (the order of packets constituting a frame) is changed between the time when it is output from the time and the time when it arrives at the subscriber side device 3. Therefore, the delay means 19 gives a time (delay time) until the multiplexed signal is generated by the multiplexing means 15 to the signal for bidirectional communication service.

  Incidentally, there is a possibility that the delay time given to the signal for the bidirectional communication service by the delay means 19 is short and adjustment of the delay times of the two systems is insufficient. In order to easily increase the delay time, the storage capacity of the delay means 19 (buffer) may be increased. For example, in the special table 2003-526263, when data is divided and transmitted to a plurality of physical ports, A technique is disclosed in which a hash value is calculated from a MAC address, an IP address, a TCP port number, etc., and a physical port is selected according to the value.

  In this method, data belonging to the same data flow is always transferred to the same physical port, so that the order of data does not change. By doing so, it is possible to prevent the influence on the subscriber side device 3 due to the difference in delay time between the two systems, and this method (calculating a hash value from the MAC address, IP address, TCP port number, etc.) Is assumed to be adopted as the sorting means 13. However, in this method, since the selection of the physical port is performed for each data flow, there is a possibility that the data flow cannot be optimally distributed to each physical port when there are only a few large-capacity data flows.

  When the rate of the bidirectional communication service signal transmission means 21 and the multiplexed signal transmission means 17 described later is 1 Gbps, four subscribers (four subscriber-side devices 3) with bidirectional communication service signals. For example, if the signal speed a of the broadcast service signal is a = 800 Mbps, the surplus bandwidth of the broadcast service signal is 200 Mbps, and the hash value indicates a service unit (example). In this case, the data for three persons of 300 Mbps × 3 persons = 900 Mbps is distributed to the two-way communication service signal transmission means 21 side, and the excess bandwidth on the multiplexed signal transmission means 17 side Of the 300 Mbps data for one person, only 200 Mbps can be allocated. You will not be able to take advantage of.

  Therefore, the distribution means 13 divides the service for bi-directional communication service, and divides the signal for the bi-directional communication service by allocating the signal for bi-directional communication service in units of MAC frames. Using all of 1 Gbps = 1200 Mbps of the bandwidth 200 Mbps + bidirectional communication service signal transmission means 21, the data for 300 Mbps × 4 persons (= 1200 Mbps) is distributed and the data can be transmitted.

  The bidirectional communication service signal transmission means 21 outputs the bidirectional communication service signal delayed by the delay means 19 to the connection means 25 connected to the optical fiber, thereby the bidirectional communication service signal. Is transmitted to the subscriber side device 3. This bidirectional communication service signal transmission means 21 transmits all bidirectional communication service signals addressed to conventional ONUs (not shown).

  The link aggregation processing means 23 is an interface on the external communication network side between the OLT function processing means 11 of the device 1 and the Internet. The link aggregation processing means 23 has a rate twice that of Gigabit Ethernet (registered trademark) by link aggregation conforming to IEEE 802.3ad-2000.

  In this embodiment, as will be described later, the bidirectional communication service signal transmission means 21 for transmitting a bidirectional communication service signal and the multiplexed signal transmission means 17 for multiplexing and transmitting the broadcast service signal. Since the rate is 1 Gbps, the rate of the link aggregation processing means 23 is 2 Gbps. However, for example, if the rate of the multiplexed signal transmission unit 17 is 10 Gbps, it is preferable to use 10 GBASE-R as an interface without using the link aggregation processing unit 23 having a rate of 2 Gbps as an interface.

  The connection means 25 is an interface connected to an optical fiber, and is configured by a general WDM coupler. An optical signal (identification information [register request signal], multiplexed signal, signal for two-way communication service) is transmitted and received through the connection means 25.

  According to this station side apparatus 1, the OLT function processing means 11 adds an LLID (label) having a predetermined value based on the identification information to the MAC frame of the signal for bidirectional communication service, and the control means 9 In the control according to the above, the distribution means 13 assigns a bidirectional communication service signal to which a label having a predetermined value is added, and a bidirectional communication service signal to which a label having a value other than the predetermined value is added. And a signal for a bidirectional communication service to which a label having a predetermined value is added fits in a surplus band of a signal for a broadcast type service detected based on the signal speed. Then, the multiplexed signal transmission means 17 and the bidirectional communication service signal transmission means 21 multiplex the signal for the bidirectional communication service and the signal for the broadcast type service to which a label having a predetermined value is added. And a signal for a bidirectional communication service to which a label having a value other than a predetermined value is added.

  As a result, the signal for the bidirectional communication service with the label having the predetermined value is accommodated in the surplus band of the signal for the broadcast type service, so that the configuration for transmitting the signal for the conventional communication type service is complicated. Without being converted, the multiplexed signal (the broadcast service signal and the bidirectional communication difference service signal labeled with a predetermined value is multiplexed) is transmitted as it is. Therefore, a communication service that transmits a signal for a bidirectional communication service and a broadcast service that transmits a signal for a broadcast service can coexist.

  In addition, according to the station side device 1, by adding a counter to each MAC frame, the subscriber side device 3 that is a receiving side that receives each signal has a frame order during transmission or analysis at the receiving side. Even if is replaced, the signal can be accurately reproduced based on the counter.

  Furthermore, according to this station side apparatus 1, even if the receiving side is equipped with the conventional ONU, the MAC frame included in the signal for the bidirectional communication service addressed to the ONU is used for the broadcast service. By avoiding multiplexing with signals, users who do not want to upgrade can continue to use conventional ONUs as they are.

(Operation of station side device)
Next, the operation of the station apparatus 1 will be described with reference to the flowchart shown in FIG. 3 (see FIG. 1 as appropriate).
The station side apparatus 1 has received the identification information transmitted from the subscriber side apparatus 3 in advance (step S1). First, the station side apparatus 1 detects the signal speed of the input broadcast-type service signal by the signal speed detecting means 7 (step S2). Further, the station side device 1 uses the OLT function processing means 11 to generate an LLID having a predetermined value and a LLID having a value other than the predetermined value in a bidirectional communication service signal input via the Internet or the like. Is added (step S3).

  Subsequently, the station side device 1 uses the control unit 9 to control the output of the bidirectional communication service signal whose output is controlled by the OLT function processing unit 11, and the distribution unit 13 controls the LLID (label) having a predetermined value. A part of the signal for the bidirectional communication service to which is added and the signal for the bidirectional communication service to which the LLID having a value other than the predetermined value is added are sorted (step S4).

  Then, the station side device 1 uses the multiplexing means 15 to generate a broadcast service signal and a part of the bidirectional communication service signal to which a LLID (label) having a predetermined value is added. Multiplexed to obtain a multiplexed signal (step S5). After that, the station side apparatus 1 adds both of the multiplexed signal by the multiplexed signal transmitting unit 17 and the LLID (label) having a value other than the predetermined value by the bidirectional communication service signal transmitting unit 21. The signal for the communication service and the remaining signal of the signal for the bidirectional communication service to which the LLID (label) having a predetermined value is added are connected via the connection means 25 to the subscriber side device 3 (and To the conventional ONU) (step S6).

(Configuration of subscriber side device)
Next, returning to FIG. 1, the configuration of the subscriber side device 3 will be described. The subscriber side device 3 is installed in the subscriber's home or the like, and receives a broadcast service signal and a bidirectional communication service signal, which are optical signals, and includes ONU function processing means 31 and identification information transmission. Means 33, multiplexed signal receiving means (receiving means) 35, sorting means 37, second filtering means (filtering means) 39, bidirectional communication service signal receiving means 41, and first filtering means (filtering means). ) 43, multiplexing means 45, control means 47, and connection means 49.

  The ONU function processing unit 31 instructs the identification information transmission unit 33 to transmit identification information, controls the first filtering unit 43 and the second filtering unit 39, and outputs a multiplexed signal ( A signal for bidirectional communication service only) is output to the outside (HN via an HGW not shown). The ONU function processing unit 31 has a function of receiving an external signal, transmitting an uplink signal transmission request to the station apparatus 1, and transmitting the uplink signal according to an instruction from the station apparatus 1.

  In the control by the ONU function processing means 31, as a result of the preamble being analyzed by the second filtering means 39 and the first filtering means 43, LLIDs addressed to itself (addressed to the device 3) and addresses of all receiving devices are added. This is performed so that only the MAC frame passed is passed. That is, the ONU function processing unit 31 notifies the second filtering unit 39 and the first filtering unit 43 of the LLID of the MAC frame passed by the second filtering unit 39 and the first filtering unit 43.

  The identification information transmission means 33 transmits identification information to the station side apparatus 1 via the connection means 49 in accordance with an instruction from the ONU function processing means 31 when the apparatus 3 is connected to the optical fiber. . The identification information transmission unit 33 transmits the identification information via the connection unit 49. However, the identification information transmission unit 33 may transmit the identification information to the link aggregation processing unit 23 via a general network.

  The multiplexed signal receiving unit 35 receives the multiplexed signal transmitted from the station side device 1 via the connecting unit 49. In addition, this multiplexed signal receiving means 35 is connected to the apparatus 3 based on the loss budget (IEEE 802.3ah standard) similar to that of the conventional E-PON in combination with the bidirectional communication service signal receiving means 41. (Allowable loss due to the optical fiber) can be ensured (the same number of branches and distance as the conventional E-PON can be realized). For example, even if the multiplexed signal transmitting means 17 described above has a rate about 10 times higher than that of the multiplexed signal receiving means 35, it is possible to ensure a comparable loss budget (for example, electronic information). Communication Society 2006 Society Conference Lecture No. B-10-31 “Examination of Power Budget in 10G-PON System” (see Tsuyoshi Suzuki and Junichi Nakagawa (Mitsubishi Electric)).

  The distributing unit 37 converts the multiplexed signal received by the multiplexed signal receiving unit 35 into a broadcast service signal having a normal MAC frame preamble and a MAC frame to which a LLID having a predetermined value is added. The two-way communication service signal having a preamble of 2 is divided into two systems. The broadcast service signal provided with the normal MAC frame preamble distributed by the distribution means 37 is output to the outside as it is and used for the bidirectional communication service provided with the MAC frame preamble to which the LLID is added. The signal is output to the second filtering means 43.

  The broadcast service signal distributed by the distribution means 37 has been described as having a normal MAC frame preamble. However, the broadcast service signal is distributed to the bidirectional communication service signal. If possible, a normal MAC frame preamble may not be provided. For example, a dedicated LLID (label) may be added for a broadcast service.

  The second filtering means 39 extracts and analyzes the preamble of the bidirectional communication service signal distributed by the distribution means 37 (here, what is added to the preamble or what is described is detected). The bidirectional communication service signal is output to the multiplexing means 45. The analysis by the second filtering means 39 refers to determining whether or not the bidirectional communication service signal has an LLID addressed to the own apparatus. Then, the second filtering means 39 passes only the signal for bidirectional communication service having the LLID addressed to the own device.

  The bidirectional communication service signal receiving means 41 receives the bidirectional communication service signal transmitted from the station side device 1 via the connection means 49.

  The first filtering means 43 extracts and analyzes the preamble of the bidirectional communication service signal received by the bidirectional communication service signal reception means 41 (here, what is added to the preamble or what is described). And only the corresponding bidirectional communication service signal is output to the multiplexing means 45 based on the control of the ONU function processing means 31. The analysis by the first filtering means 43 refers to determining whether or not the bidirectional communication service signal has an LLID addressed to the own apparatus. Then, the first filtering means 43 passes only the signal for the bidirectional communication service having the LLID addressed to its own device.

  The processing by the second filtering means 39 and the first filtering means 43 may be performed by the ONU function processing means 31 as long as the interface between the ONU function processing means 31 and the multiplexing means 45 is made high speed. The second filtering means 39 and the first filtering means 43 are not essential components. Moreover, you may comprise so that the distribution means 37 may perform the process by the 2nd filtering means 39. FIG.

  The multiplexing means 45 multiplexes the signal for bidirectional communication service filtered by the second filtering means 39 and the first filtering means 43 (that is, the preamble is extracted and analyzed) under the control of the control means 47, The multiplexed signal is output to the ONU function processing means 31. The multiplexing unit 45 outputs the LLID and the counter added to the preamble of the bidirectional communication service signal filtered by the second filtering unit 39 and the first filtering unit 43 to the control unit 47. The MAC frame of the multiplexed signal output from the multiplexing unit 45 is in GMII format.

  Based on the LLID and the counter added to the preamble of the bidirectional communication service signal filtered by the second filtering means 39 and the first filtering means 43, the control means 47 uses the bidirectional communication service by the multiplexing means 45. The order in which the signals are multiplexed is controlled so as to be the original order. That is, the control unit 47 uses the two-way communication service signals output from the second filtering unit 39 and the first filtering unit 43 based on the preamble counters of these two-way communication service signals. By controlling the multiplexing means 45, it is possible to prevent the MAC frame order from being changed due to the difference in arrival order.

  In the station side device 1, when a signal for bidirectional communication service is distributed for each data flow without using a counter in the preamble, multiplexing is performed without considering the delay time for each system. The control unit 47 may control the multiplexing unit 45.

  A bidirectional communication service signal including a MAC frame without a counter transmitted from the station side device 1 to all reception side devices is always a bidirectional communication service signal receiving means 41. Therefore, it is not necessary to consider that the MAC frame is switched.

  The connection means 49 is an interface connected to an optical fiber, and is configured by a general WDM coupler. An optical signal (identification information [register request signal], multiplexed signal, signal for bidirectional communication service) is transmitted / received via the connection means 49.

  According to this subscriber side device 3, the multiplexed signal receiving means 35 multiplexes the signal for bidirectional communication service to which the LLID (label) is added multiplexed into the surplus band of the signal for broadcast type service. The bidirectional communication service signal reception means 41 receives a bidirectional communication service signal to which an LLID (label) having a value other than a predetermined value is added. Then, the distribution means 37 distributes the multiplexed signal into a bidirectional communication service signal and a broadcast service signal with a label having a predetermined value, and the second filtering means 39 and the first filtering. The means 43 extracts the preamble information from the bidirectional communication service signal to which a label having a predetermined value is added and the bidirectional communication service signal to which a label having a value other than the predetermined value is added. Based on the preamble information, the control unit 47 adjusts the order of multiplexing, multiplexes and outputs the signals, and outputs a signal for the broadcast type service.

  As a result, in the E-PON system S based on this communication type service, when adding a broadcast type service, the subscriber side can add a conventional ONU that supports only the communication type service and a broadcast type service. When the subscriber side apparatus 3 corresponding to both the service and the communication type service coexists, the surplus bandwidth of the signal for the broadcast type service is used for the signal for the two-way communication service. The communication type service and the broadcast type service can coexist without complicating the configuration for processing the signal for use, and the downlink band can be expanded.

(Operation of subscriber side device)
Next, the operation of the subscriber apparatus 3 will be described with reference to the flowchart shown in FIG. 4 (see FIG. 1 as appropriate).
In advance, the subscriber side device 3 transmits identification information to the station side device 1 (step S11). First, the subscriber side apparatus 3 receives the multiplexed signal transmitted from the station side apparatus 1 by the multiplexed signal receiving means 35, and is transmitted from the station side apparatus 1 by the bidirectional communication service signal receiving means 41. Bidirectional communication service signal (bidirectional communication service signal to which an LLID (label) having a value other than a predetermined value is added and an LLID (label) having a predetermined value is added. The remaining signal of the service signal is received (step S12).

  Subsequently, the subscriber side device 3 uses the distribution unit 37 to convert the multiplexed signal into a part of the signal for the bidirectional communication service to which the LLID (label) having a predetermined value is added, and the broadcast type. Distribution to service signals (step S13). Then, the subscriber side device 3 extracts and analyzes the preamble from the bidirectional communication service signal by the second filtering means 39 and the first filtering means 43 (step S14).

  Then, the subscriber side apparatus 3 multiplexes the two-way bidirectional communication service signals output from the second filtering means 39 and the first filtering means 43 by the multiplexing means 45, and sends them to the ONU function processing means 31. Output (step S15). Thereafter, the subscriber side device 3 outputs the broadcast service signal from the distribution unit 37 and the bidirectional communication service signal from the ONU function processing unit 31 to the outside (step S16).

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, in the E-PON system S of the present embodiment, it has been described that Gigabit Ethernet (registered trademark) is used for transmission / reception of a broadcast service signal and a bidirectional communication service signal, but the present invention is not limited thereto. Is not to be done. In addition, a broadcast service signal and a bidirectional communication service signal are transmitted using a single optical fiber using a wavelength division multiplexing technique. However, the present invention is not limited to this. Alternatively, an optical fiber having a larger number of cores) may be used.

1 is a block diagram of an E-PON system according to an embodiment of the present invention. It is the figure shown about the MAC frame handled by an E-PON system. 3 is a flowchart showing the operation of the station side device shown in FIG. 1. It is the flowchart which showed the operation | movement of the subscriber side apparatus shown in FIG. It is the figure which showed the conventional E-PON system. It is the figure shown about the MAC frame handled with the conventional E-PON system. It is the figure which showed the conventional PON system to which the broadcast type | formula video delivery apparatus was added.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Station side apparatus 3 Subscriber side apparatus 5 Identification information reception means 7 Signal speed detection means 9, 47 Control means 11 OLT function processing means 13, 37 Distribution means 15, 45 Multiplexing means 17 Multiplexed signal transmission means 19 Delay means 21 Bidirectional communication service signal transmission means 23 Link aggregation processing means 25, 49 Connection means 31 ONU function processing means 33 Identification information transmission means 35 Multiplexed signal reception means 39 Second filtering means 41 Bidirectional communication service signal reception means 43 One filtering means S E-PON system

Claims (6)

At least one of the plurality of transmission means is a station side device that transmits a signal for bidirectional communication service,
Identification information receiving means for receiving identification information indicating a receivable signal transmitted from a receiving apparatus capable of receiving at least a signal for a two-way communication service;
Detecting a surplus band of a transmission means other than the transmission means for transmitting the signal for the bidirectional communication service or setting a predetermined surplus band;
Label adding means for adding a label having at least a different value for each receiving device to the frame of the signal for the bidirectional communication service based on the identification information received by the identification information receiving means;
A part of the signal for the bidirectional communication service to which a label having a predetermined value is added among the labels added by the label adding means, and a signal for the bidirectional communication service other than the part of the signal A distribution means for distributing
Control means for controlling the output of the sorting means so that a part of the signal for bidirectional communication service to which the label having the predetermined value is added is accommodated in the surplus band,
The plurality of transmission means include a transmission means for transmitting a part of the signal for the bidirectional communication service distributed by the distribution means, and bidirectional communication other than the partial signal distributed by the distribution means. A station-side device comprising: a transmission means for transmitting a service signal.   2. The counter adding means according to claim 1, further comprising: a counter adding means for adding a counter indicating the order of the frames to a signal for a bidirectional communication service to which a label having a predetermined value is added. Station side device. Multiplexing means for multiplexing a part of the signals for the bidirectional communication service distributed by the distribution means and the signal for the broadcast type service;
Signal speed detecting means for detecting a signal speed of the signal for the broadcast service,
The surplus bandwidth acquisition means obtains a difference between a bandwidth of a transmission means for transmitting a part of the signal for the bidirectional communication service and a bandwidth occupied according to the signal speed detected by the signal speed detection means. The station apparatus according to claim 1, wherein the surplus band is detected. A subscriber-side device that receives a bidirectional communication service signal or a plurality of downlink signals including at least the bidirectional communication service signal,
Identification information transmitting means for transmitting identification information indicating that the plurality of downlink signals can be received;
Receiving means for receiving a part of the signals for the bidirectional communication service or the plurality of downlink signals;
Bi-directional communication service signal receiving means for receiving bi-directional communication service signals other than the part of the signals;
Filtering is performed on the bidirectional communication service signal received by the reception unit and the bidirectional communication service signal reception unit, and information on a preamble portion of each frame of the bidirectional communication service signal is extracted. Filtering means for passing a signal for a bidirectional communication service transmitted to the device;
A multiplexing means for multiplexing the signal for the bidirectional communication service passed by the filtering means;
A subscriber-side device comprising:   5. The control unit according to claim 4, further comprising: a control unit configured to adjust an order of the signals for the bidirectional communication service multiplexed by the multiplexing unit based on a counter representing the order of frames included in the preamble unit. The subscriber side device as described in 1. 6. The subscriber according to claim 4, further comprising a distribution unit that distributes the bidirectional communication service signal and other signals when the reception unit receives the plurality of downlink signals. Side device.

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