JP6599063B2 - Optical communication system - Google Patents

Description

  The present invention relates to an optical communication system, and more particularly to an optical communication system for performing optical uplink scheduling for reducing delay time.

  In a wireless communication system such as LTE (Long Term Evolution), a terminal performs wireless communication with a base station. Usually, one base station communicates with a plurality of terminals, so that the base station dynamically allocates a finite communication capacity (hereinafter referred to as a resource) to each terminal so that signals between terminals do not interfere with each other. Do. For example, taking LTE uplink communication as an example, a terminal (hereinafter referred to as a UE) first requests a bandwidth from the base station when transmitting uplink data to the base station. When the base station receives the bandwidth request, in order to obtain information necessary for scheduling uplink data, such as the buffer amount and channel state, from the UE, the base station allocates resources for sending the information to the UE, and The resource is notified as a response. The UE transmits information necessary for uplink data scheduling to the base station using the allocated resources. The base station performs scheduling using the information, and allocates resources for transmitting uplink data to the UE using a scheduling grant. Through these exchanges, the UE can send uplink data to the base station for the first time.

  On the other hand, a radio system in which a C-RAN configuration is introduced in which a base station is separated into a master station apparatus having a radio modulation / demodulation function and a slave station apparatus having a radio transmission / reception function has been proposed. In the wireless system, the base station is separated into a master station device and a slave station device, and the master station devices are aggregated into one station, thereby efficiently realizing cooperation control between the slave stations. In such a wireless system, the connection form between the master station apparatus and the slave station apparatus can be a one-to-many connection form using a PON (Passive Optical Network) system. In this case, the master station device and the slave station device are connected by an optical fiber and an optical splitter. With this configuration, it is possible to reduce the number of master station devices and the number of optical fibers with respect to the number of slave station devices, thereby improving economy.

  Also in the PON system, one OLT (Optical Line Terminal) communicates with a plurality of ONUs (Optical Network Units). For this reason, the OLT performs scheduling for dynamically allocating communication capacity to each ONU. When performing scheduling, the ONU firstly stores information on the amount of data stored in its transmission buffer (hereinafter referred to as REPORT information) at the timing specified by the transmission permission signal sent from the OLT. , Send to OLT. The OLT performs scheduling based on the REPORT information, assigns a resource for transmitting uplink data to each ONU, and notifies the assigned resource to each ONU. Through these exchanges, each ONU can transmit uplink data to the OLT for the first time. However, when a PON system is used as a connection form between a master station device and a slave station device, each ONU notifies the OLT of REPORT information stored in each ONU, resources are allocated, and uplink data is transmitted. A delay occurs.

  In order to realize C-RAN, it is necessary to reduce the data transfer delay between the master station device and the slave station device. As a technique for reducing a delay when a PON system is used as a connection form between a master station device and a slave station device, for example, there is a method described in Patent Document 1. In the FDD scheme, the radio scheduler always transmits radio uplink scheduling information about 4 ms before the antenna receives. In Patent Document 1, the optical scheduler allocates a band using this fact.

  Also, for example, in Patent Document 2, when a PON system is used for connection between a host device as a master station and a base station as a slave station, a base station under the ONU transmits an uplink transmission to the mobile terminal. There has been proposed a technique for realizing low delay by giving similar uplink transmission permission information to the ONU when granting permission.

International Publication No. 2014/077168 Japanese Patent No. 5878991

  In order to transfer wireless uplink data with reduced delay, it is necessary to synchronize the optical uplink scheduling timing with the wireless uplink scheduling timing. In the prior art described in Patent Document 1 and Patent Document 2 described above, optical resources are allocated based on the timing at which wireless scheduling information is received. However, according to the related art, between the reception timing of the radio scheduling information and the subframe head timing, due to processing delay in the master station, in the slave station, in the ONU, and in the OLT, or in the slave station − There is a possibility that a deviation of the order of several tens of us to 1 ms occurs due to a transmission delay between ONUs and between a master station and an OLT. In that case, there is a problem that the optical uplink scheduling cannot be performed accurately and the uplink delay time increases.

  The present invention has been made to solve such a problem. In the station-side device, the light whose delay time is reduced by accurately grasping the reception time of data from the slave station device in the terminal-side device. An object of the present invention is to obtain an optical communication system that enables uplink scheduling.

  The present invention connects a station side device connected to a master station device, a terminal side device connected to a slave station device that performs wireless communication with the terminal, and the station side device and the terminal side device. An optical transmission path, wherein the terminal side device receives wireless data transmission timing information indicating transmission timing at which the terminal transmits wireless data from the slave station device, and receives the wireless data transmission timing information. A reception time detection unit that detects time; and a transmission unit that transmits a notification frame that notifies the station side device of the reception time. The station side device stores radio uplink scheduling information managed by the master station device. A wireless information extraction unit to extract; a time extraction unit to extract the reception time from the notification frame transmitted by the transmission unit; and the wireless information extraction unit based on the reception time extracted by the time extraction unit. Based on the estimated time calculation unit for calculating the estimated reception time at which the terminal side device receives data corresponding to the scheduling information from the slave station device, and the terminal side device based on the estimated reception time and the radio uplink scheduling information An optical communication system comprising: a scheduling unit that generates optical uplink scheduling information for performing data transmission from the station to the station side device; and a notification unit that notifies the terminal side device of the optical uplink scheduling information.

  According to the optical communication system of the present invention, the terminal side device receives the wireless data transmission timing information, and notifies the station side device of the reception time of the information. By accurately grasping the reception time of data from the station device, the radio uplink scheduling information managed by the master station device and the optical uplink scheduling information can be matched accurately, and as a result, the delay time is reduced. Enables uplink scheduling.

It is a block diagram which shows the structure of the optical communication system which concerns on Embodiment 1 of this invention. It is the figure which showed the structure of the radio | wireless frame in the optical communication system which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the optical communication system which concerns on Embodiment 2 of this invention. It is the figure which showed the structure of the radio | wireless frame in the optical communication system which concerns on Embodiment 2 of this invention. It is a flowchart which shows the flow of a process in the optical communication system which concerns on Embodiment 1 of this invention. It is a flowchart which shows the flow of a process in the optical communication system which concerns on Embodiment 1 of this invention. It is a flowchart which shows the flow of a process in the optical communication system which concerns on Embodiment 1 of this invention. It is the block diagram which showed the hardware constitutions of OLT in the optical communication system which concerns on Embodiment 1 of this invention. It is a block diagram which showed the hardware configuration of ONU in the optical communication system which concerns on Embodiment 1 of this invention. It is the block diagram which showed the hardware constitutions of OLT in the optical communication system which concerns on Embodiment 1 of this invention. It is a block diagram which showed the hardware configuration of ONU in the optical communication system which concerns on Embodiment 1 of this invention.

Embodiment 1 FIG.
1 is a block diagram showing the configuration of an optical communication system according to Embodiment 1 of the present invention. In Embodiment 1, a base station cooperative optical communication system will be described as an example of an optical communication system. In the first embodiment, a PON system is applied as a connection form between a master station device and a slave station device.

  FIG. 1 shows an example in which the radio frame number and subframe number of radio data are stored in radio uplink scheduling information included in downlink data from the master station device. The radio data is composed of radio frames composed of a sequence of a plurality of subframes. For example, in LTE, the time length of one subframe is 1 ms, and the time length of one radio frame is 10 ms. That is, in the case of LTE, one radio frame is composed of 10 subframes. Moreover, FIG. 2 is a figure which shows an example of a structure of the radio | wireless uplink scheduling information which a parent station apparatus manages.

  In FIG. 1, a master station device 1 having a wireless modulation / demodulation function and a slave station device 2 having a wireless transmission / reception function are provided. The master station device 1 and the slave station device 2 constitute a base station. An optical subscriber terminal device (hereinafter referred to as OLT) 4 is connected to the master station device 1. The slave station device 2 performs wireless communication with the wireless terminal (UE) 3. An optical network unit (hereinafter referred to as ONU) 5 is connected to the slave station device 2. The OLT 4 and the ONU 5 are connected by an optical transmission line 6. The optical transmission line 6 is composed of, for example, an optical fiber. In FIG. 1, only one ONU 5 is shown, but actually, a plurality of ONUs 5 are provided. In that case, those ONUs 5 are connected to one OLT 4 via an optical splitter (not shown). The OLT 4 needs to perform scheduling for dynamically allocating capacity to each ONU, particularly when there are a plurality of ONUs 5. Since the OLT 4 is arranged on the master station device 1 side, it is called a station side device. On the other hand, since the ONU 5 is arranged on the UE 3 side, it is called a terminal side device.

  The master station device 1 outputs downlink data including the radio uplink scheduling information to the OLT 4. The radio uplink scheduling information includes allocation resource information for instructing each UE 3 of resources allocated to each UE 3 by the master station device 1. The allocation resource is information that instructs each UE 3 in which time band and in which frequency band a subframe is to be transmitted. When transmitting uplink data to the master station device 1, each UE 3 transmits uplink data using the resource indicated by the allocated resource information. Further, as described above, the radio uplink scheduling information further includes a radio frame number and a subframe number of radio data for each slave station device 2 and for each UE 3.

  Hereinafter, the configuration of the OLT 4 will be described. The OLT 4 includes a wireless information extraction unit 11, a resource conversion unit 12, a number extraction unit 13, a GPS extraction unit 14, a time extraction unit 15, a time estimation unit 16, an MPCP unit 17, a time conversion unit 18, , A PON scheduler 19, a multiplexing unit (hereinafter referred to as MUX) 20, and an optical transmission / reception unit 21. Hereinafter, these components will be described.

  The radio information extraction unit 11 extracts radio uplink scheduling information from downlink data from the master station device 1. The radio uplink scheduling information includes allocation resource information, a radio frame number, and a subframe number.

  The resource conversion unit 12 searches for the radio uplink data amount for each UE 3 from the allocated resource information included in the radio uplink scheduling information extracted by the radio information extraction unit 11, and accumulates data for each ONU 5 that receives the uplink data of the UE 3. The amount is calculated and notified to the PON scheduler 19 as optical resource information.

  The number extraction unit 13 extracts the radio frame number and the subframe number from the radio uplink scheduling information extracted by the radio information extraction unit 11 and outputs the radio frame number and the subframe number to the time estimation unit 16.

  The GPS extraction unit 14 manages the absolute time based on 1PPS and ToD from the GPS receiver 7 provided outside.

  The time extraction unit 15 extracts the subframe head notification frame multiplexed on the uplink data from the uplink data from the ONU 5. The subframe head notification frame includes a radio frame number, a subframe number, and a subframe head time. Here, the subframe head time is the time when the ONU 5 sends the SUBFRAME. Indicates the reception time when the indication frame is received. SUBFRAME. The indication frame includes information indicating transmission timing information at which the UE 3 transmits a subframe.

  The time estimation unit 16 estimates the reception time at which the wireless data indicated by the wireless frame number and the subframe number extracted by the number extraction unit 13 is received by the ONU 5 as an absolute time, and outputs it as the ONU reception time. Specifically, the time estimation unit 16 receives the radio frame number, subframe number, and subframe head time included in the subframe head notification frame from the ONU 5 from the time extraction unit 15. The time estimation unit 16 stores in advance the time length of one subframe, which is a system setting value. Further, the radio frame number and the subframe number extracted by the number extraction unit 13 are input to the time estimation unit 16. The time estimation unit 16 collates the radio frame number and subframe number extracted by the number extraction unit 13 with the radio frame number and subframe number included in the head notification frame, thereby subcarriers included in the head notification frame. From the frame start time, the subframe start time corresponding to the radio frame number and subframe number extracted by the number extraction unit 13 is searched for and output as the ONU reception time.

Note that the number extraction unit 13, the time extraction unit 15, and the time estimation unit 16 use the reception time extracted by the time extraction unit 15 to transmit data corresponding to the radio uplink scheduling information to the ONU 5 that is a terminal side device as a child. An estimated time calculation unit for calculating an estimated reception time received from the station apparatus 2 is configured.
In addition, the number extraction unit 13 constitutes a first number extraction unit that extracts a radio frame number and a subframe number from the radio uplink scheduling information.
In addition, the time extraction unit 15 constitutes a second number extraction unit that extracts a radio frame number and a subframe number from a subframe head notification frame as a notification frame.
The time estimation unit 16 also includes the radio frame number and subframe number extracted by the number extraction unit 13 that is the first number extraction unit, and the radio frame number extracted by the time extraction unit 15 that is the second number extraction unit. The radio frame number extracted by the number extraction unit 13 as the first number extraction unit from the reception time included in the subframe head notification frame extracted by the time extraction unit 15 by collating with the subframe number And a time estimation unit that searches for a reception time corresponding to the subframe number and outputs the reception time obtained by the search as an ONU reception time that is an estimated reception time.

  The MPCP unit 17 manages the local time that is the system management time of the PON system configured by the OLT 4 and the ONU 5. Further, the MPCP unit 17 generates a control frame (hereinafter referred to as a Gate frame) for notifying resource allocation information and transmission permission timing to the ONU 5 based on optical uplink scheduling information from the PON scheduler 19 described later. .

  Based on the current local time managed by the MPCP unit 17 and the absolute time from the GPS extraction unit 14, the time conversion unit 18 converts the ONU reception time expressed by the absolute time from the time estimation unit 16 to the local time. It is converted and output as ONU data reception timing. That is, the ONU data reception timing is the ONU reception time expressed in the Local Time. Since the ONU reception time output from the time estimation unit 16 is expressed in absolute time, it cannot be used by the PON scheduler 19 as it is. The data that can be used by the PON scheduler 19 needs to be expressed in the local time that is the system management time of the PON system. Therefore, the time conversion unit 18 converts the ONU reception time from the absolute time to the local time. Processing is in progress.

  The PON scheduler 19 schedules resources to be allocated to each ONU 5 from the optical resource information from the resource conversion unit 12 and the ONU data reception timing from the time conversion unit 18 and outputs them as optical uplink scheduling information. The PON scheduler 19 generates optical uplink scheduling information for performing data transmission from the ONU 5 that is the terminal side device to the station side device 2 based on the ONU data reception timing indicating the estimated reception time and the radio uplink scheduling information. The scheduling unit is configured.

  The MUX 20 multiplexes the Gate frame generated by the MPCP unit 17 with the downlink data.

  The optical transmission / reception unit 21 receives the uplink data from the ONU 5 and outputs it to the time extraction unit 15 and the master station device 1. Further, the optical transmission / reception unit 21 outputs the downlink data multiplexed by the MUX 20 and the Gate frame to the ONU 5.

  The MPCP unit 17, the MUX 20, and the optical transmission / reception unit 21 constitute a notification unit that notifies the optical uplink scheduling information to the ONU 5 that is the terminal side device.

  Next, the configuration of the ONU 5 will be described. The ONU 5 includes a number extraction unit 22, a GPS extraction unit 23, a time detection unit 24, a frame generation unit 25, an MPCP unit 26, a transmission control unit 27, an optical transmission / reception unit 28, and a multiplexing unit (hereinafter referred to as MUX). 29).

  The number extraction unit 22 obtains the SUBFRAME. The indication frame is extracted and SUBFRAME. A radio frame number and a subframe number included in the indication frame are acquired. The acquired radio frame number and subframe number are output to the frame generation unit 25. In addition, the number extraction unit 22 is a sub-frame. A frame reception trigger indicating reception of the indication frame is generated. The generated frame reception trigger is output to the time detection unit 24.

  The GPS extraction unit 23 manages the absolute time based on 1PPS and ToD from the GPS receiver 7 provided outside.

  From the frame reception trigger from the number extraction unit 22 and the absolute time from the GPS extraction unit 23, the time detection unit 24 determines that the ONU 5 is SUBFRAME. The reception time when the indication frame is received is detected as an absolute time, and is output as the subframe head time.

  The number extraction unit 22 and the time detection unit 24 receive the wireless data transmission timing information from the slave station device 2 by receiving the wireless data transmission timing information indicating the transmission timing at which the UE 3 as the terminal transmits the wireless data. A reception time detection unit for detecting time is configured.

  The frame generation unit 25 generates a subframe head notification frame that includes the radio frame number and subframe number acquired by the number extraction unit 22 and the subframe head time detected by the time detection unit 24.

  The MPCP unit 26 extracts and processes the Gate frame from the downlink data received by the optical transmission / reception unit 28 from the OLT 4, and outputs a transmission permission signal indicating the transmission permission timing included in the Gate frame.

  The transmission control unit 27 controls the transmission of the uplink data and the subframe head notification frame according to the transmission permission timing of the transmission permission signal from the MPCP unit 26.

  The optical transmission / reception unit 28 transmits uplink data and a subframe head notification frame to the OLT 4 under the control of the transmission control unit 27. Further, the optical transmission / reception unit 28 receives the downlink data from the OLT 4 and outputs it to the MPCP unit 26 and the slave station device 2.

  The frame generation unit 25, the transmission control unit 27, and the optical transmission / reception unit 28 constitute a transmission unit that transmits a subframe head notification frame as a notification frame for notifying the reception time of the ONU 5 to the OLT 4 that is the station side device. is doing.

  The MUX 29 multiplexes the subframe head notification frame generated by the frame generation unit 25 with the uplink data, and outputs the multiplexed data to the transmission control unit 27.

  Next, the operation will be described.

  First, a process for grasping the radio frame number and subframe number of the slave station device 2 and the subframe head time in the ONU 5 will be described. FIG. 5 shows an example of a flow of subframe head time grasping processing.

  In FIG. 5, first, step S1 will be described. The ONU 5 receives the uplink data from the slave station device 2. Uplink data includes main signal data and SUBFRAME. and an indication frame. When the ONU 5 receives the uplink data from the slave station device 2, the ONU 5 receives the SUBFRAME. An indication frame is received. Therefore, SUBFRAME. The reception time of the indication frame indicates the time when the head of the subframe is received. Therefore, here, this time is called a subframe head time. Uplink data received by the ONU 5 is transferred to the number extraction unit 22. In step S1, the number extraction unit 22 determines that the ONU 5 is SUBFRAME. A frame reception trigger indicating that the indication frame has been received is generated. The frame reception trigger is output to the time detection unit 24.

  Next, step S2 will be described. The ONU 5 receives a GPS signal (1PPS, ToD) from an external device such as the GPS receiver 7 or a host device, and the GPS extraction unit 23 grasps the absolute time using the GPS signal. This absolute time is notified to the time detection unit 24. In step S <b> 2, the time detection unit 24 uses the frame reception trigger from the number extraction unit 22 and the absolute time from the GPS extraction unit 23 to use the SUBFRAME. The reception time of the indication frame is detected and notified to the frame generation unit 25 as the subframe head time.

  In step S3, the number extraction unit 22 extracts a radio frame number and a subframe number from the uplink data. The extracted radio frame number and subframe number are notified to the frame generation unit 25.

  In step S4, the frame generation unit 25 uses the radio frame number and subframe number extracted by the number extraction unit 22 and the subframe start time detected by the time detection unit 24 to generate a subframe start notification frame. Generate. Therefore, the subframe head notification frame includes a radio frame number, a subframe number, and a subframe head time.

  In step S <b> 5, the subframe head notification frame is multiplexed with the uplink data by the MUX 29 and transmitted to the transmission control unit 27. On the other hand, the MPCP unit 26 extracts the transmission permission timing from the transmission permission signal included in the Gate frame transmitted from the OLT 4. The transmission control unit 27 transmits the multiplexed uplink data and the subframe head notification frame to the OLT 4 according to the transmission permission timing.

  Next, a process for determining the subframe head time from the subframe head notification frame in the OLT 4 will be described. FIG. 6 shows an example of a flow of subframe head time grasping processing.

  In FIG. 6, in step S <b> 11, the OLT 4 receives a subframe head notification frame multiplexed with uplink data from the ONU 5. The subframe head notification frame is input to the time extraction unit 15. The time extraction unit 15 extracts a subframe head notification frame.

  In step S12, the time extraction unit 15 extracts the radio frame number, the subframe number, and the subframe head time stored in the subframe head notification frame, and notifies the time estimation unit 16 of them.

  In step S13, the time estimation unit 16 obtains the subframe head time corresponding to the radio frame number and the subframe number of the OLT 4, and updates the ONU reception time. Specifically, the time estimation unit 16 collates the radio frame number and subframe number extracted by the number extraction unit 13 with the radio frame number and subframe number extracted by the time extraction unit 15, thereby obtaining a time extraction unit. The subframe start time corresponding to the radio frame number extracted by the number extraction unit 13 and the subframe number is searched from the subframe start time extracted at 15. The time estimation unit 16 outputs the subframe head time obtained by the search as an estimated value of the reception time in the ONU 5. Here, the estimated value is referred to as ONU reception time.

  The processes of steps S11 to S13 are performed for each ONU 5 connected to the OLT 4.

  As a result, the subframe head time arriving at the ONU 5 from the slave station device 2 can be accurately grasped by the OLT 4 for each ONU 5. Since the subframe head time is a value obtained by the frame reception trigger in the ONU 5, it is a measured reception time. For this reason, a shift caused by the processing delay of the slave station device 2, the processing delay of the ONU 5, and the transmission delay between the slave station device 2 and the ONU 5 is included. An accurate reception time can be acquired by obtaining the reception time including the deviation by a frame reception trigger. By notifying the OLT 4 of the accurate reception time obtained in this way, the accurate reception time can be grasped also in the OLT 4.

  Next, the flow of optical uplink scheduling processing to the ONU 5 using the above radio frame / subframe head time will be described. FIG. 7 shows an example of a flow of optical uplink scheduling processing to the ONU 5 using the subframe head time.

  First, downlink data including radio uplink scheduling information is transmitted from the master station device 1 to the OLT 4.

  In step S <b> 21, the downlink data received by the OLT 4 is input to the wireless information extraction unit 11. The radio information extraction unit 11 extracts a radio main signal and radio uplink scheduling information from downlink data. In the radio uplink scheduling information, as shown in FIG. 2, a radio frame number and a subframe number are stored as slave station reception timing information for each slave station device 2 and for each UE 3, and RIV, MCS are assigned resource information. Is stored. In FIG. 2, RIV is described as RBA, and MCS is described as M # 1 and M # 2. The extracted radio uplink scheduling information is transferred to the resource conversion unit 12 and the number extraction unit 13, respectively. The number extraction unit 13 extracts a radio frame number and a subframe number for each slave station device 2 and each UE 3 from the radio uplink scheduling information. The extracted radio frame number and subframe number are transferred to the time estimation unit 16.

  In step S22, the resource conversion unit 12 extracts allocation resource information for each UE 3 from the radio uplink scheduling information, and calculates an uplink data amount from the extracted allocation resource information for each UE 3. The calculated uplink data amount is notified to the PON scheduler 19.

  In step S23, the time estimation unit 16 uses the radio frame number, the subframe number, the subframe head time, and the time length of one subframe, which is a system setting value, included in the subframe head notification frame from the ONU 5. Then, the subframe start time corresponding to the radio frame number and the subframe number extracted by the number extracting unit 13 is obtained from the subframe start times included in the subframe start notification frame, and the subframe start time is set as the time. It rearranges in order and outputs it to the time conversion part 18 as ONU reception time.

  In step S24, the time conversion unit 18 converts the ONU reception time from the absolute time representation to the local time representation using the current local time managed by the MPCP unit 17 and the absolute time from the GPS extraction unit 14. Thus, the ONU data reception timing is obtained. The ONU reception timing is output to the PON scheduler 19.

  Next, steps S25 to S29 are executed. In the processes of steps S25 to S29, the PON scheduler 19 performs optical uplink scheduling for each ONU 5 from the ONU data reception timing and the uplink data amount included in the optical resource information for each slave station device 2 and for each UE 3. The MPCP unit 17 is notified. At this time, since the ONU data reception timing does not include a shift due to the round trip delay time between the OLT 4 and the ONU 5, the PON scheduler 19 performs the uplink scheduling considering the round trip delay time between the OLT 4 and the ONU 5 as well. It is more desirable. The MPCP unit 17 generates a Gate frame based on this optical uplink scheduling information and notifies the ONU 5 of it. The Gate frame includes a transmission permission signal indicating a transmission permission timing that permits the ONU 5 to transmit uplink data to the OLT 4.

  Hereinafter, steps S25 to S29 will be described. The processes in steps S25 to S29 are repeated for each preset allocation cycle.

  In step S25, the PON scheduler 19 stores all data from the UE 3 that is simultaneously received by the slave station device 2 according to the system setting value, obtains the number of frames to be transmitted to the ONU 5, and sets it to N [i].

  In step S26, the PON scheduler 19 determines the frame length of N [i] frames from the system design value and the data amount for each UE3.

  In step S27, according to the RTT of the ONU 5 and the external network device configuration information, the data reception time is converted into the frame transmission start time of N [i] frames of the slave station device 2.

  The PON scheduler 19 executes the processing of steps S25 to S27 for each ONU 5 connected to the OLT 4. Then, when the processing of steps S25 to S27 is completed for all ONUs 5, the process proceeds to step S28.

  In step S28, the PON scheduler 19 adds the overhead generated in the PON section based on the N [i] total transmission start times and frame lengths, and assigns transmission permission for all ONUs 5.

  In step S29, the PON scheduler 19 allocates a surplus bandwidth to all ONUs 5 for uplink data generated independently of the optical uplink scheduling information.

  Next, examples of hardware configurations of the OLT 4 and the ONU 5 that realize the first embodiment are shown in FIGS. 8 and 9, respectively. The function of each part of the OLT 4 and the ONU 5 shown in FIG. 1 is realized by a processing circuit. When the processing circuit is dedicated hardware, the processing circuit is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

  Further, another example of the hardware configuration of the OLT 4 and the ONU 5 that realizes the first embodiment is shown in FIGS. When the processing circuit is a CPU, the functions of the OLT 4 and ONU 5 shown in FIG. 1 are realized by software, firmware, or a combination thereof. Software and firmware are described as programs and stored in a memory. The processor which comprises a processing circuit implement | achieves the function of each above-mentioned part by reading and executing the program recorded on memory.

  In addition, about each function, a part may be implement | achieved by exclusive hardware and a part may be implement | achieved by software or firmware. Further, the configurations of the OLT 4 and the ONU 5 may be combined with FIGS. As described above, the processing circuit can realize the above-described functions by hardware, software, firmware, or a combination thereof.

  As described above, in the first embodiment, the SUBFRAME. By receiving the indication frame and notifying the reception time of the frame to the OLT 4, the radio uplink scheduling information for each UE 3 and each slave station device 2 managed by the master station device 1, and the optical uplink scheduling information in the PON By accurately matching these, resource allocation with reduced wireless data storage time in the ONU 5 can be performed, and the uplink delay time is reduced.

  As described above, in the optical communication system according to the first embodiment, the ONU 5 that is the terminal-side device transmits the SUBFRAME. Which is the radio data transmission timing information indicating the transmission timing at which the UE 3 transmits the radio data. A number extraction unit 22 and a time detection unit 24 that receive an indication frame from the slave station device 2 and detects the reception time when the frame is received, and a subframe head notification that notifies the reception time to the OLT 4 that is the station side device And a transmission unit (25, 27, and 28) for generating and transmitting a frame.

  The OLT 4 serving as a station side device includes a radio information extraction unit 11 that extracts radio uplink scheduling information managed by the master station device 1 and a subframe head notification frame transmitted by the transmission units (25, 27, and 28). The time extraction unit 15 that extracts the reception time from the reception time, and the reception time estimated value at which the ONU 5 receives the wireless data corresponding to the wireless uplink scheduling information from the slave station device 2 based on the reception time extracted by the time extraction unit 15 PON that generates optical uplink scheduling information for data transmission from the ONU 5 to the OLT 4 based on the estimated time calculation unit (13, 15, and 16) to be calculated, the estimated value of the reception time, and the radio uplink scheduling information A scheduler 19 and notification units (17, 20, and 21) for notifying the optical uplink scheduling information to the ONU 5 are provided. To have.

  Thus, in the first embodiment, the ONU 5 performs the SUBFRAME. By receiving the indication frame and notifying the reception time of the frame to the OLT 4, processing delay in the master station device 1, slave station device 2, ONU 5, OLT 4, and between the slave station device 2 and the ONU 5, The OLT 4 can accurately grasp the reception time at the ONU 5 including the deviation caused by the transmission delay between the station apparatus 1 and the OLT 4. Thereby, resource allocation for reducing the radio data storage time in the ONU 5 becomes possible, and the radio uplink scheduling information for each UE 3 and each slave station device 2 managed by the master station device 1 and the optical uplink scheduling information in the PON are stored. Can be matched exactly. As described above, in the first embodiment, in the wireless communication, the OLT 4 accurately grasps the reception time of the data from the slave station device 2 in the ONU 5, thereby suppressing the uplink data transmission delay time. Enable.

  In Embodiment 1, the radio uplink scheduling information includes a radio frame number and a subframe number of radio data. In Embodiment 1, the estimated time calculation unit (13, 15, 16) includes a number extraction unit 13 that extracts a radio frame number and a subframe number from radio uplink scheduling information, and a radio frame from a subframe head notification frame. A time extraction unit 15 as a second number extraction unit for extracting numbers and subframe numbers; a radio frame number and subframe number extracted by the number extraction unit 13; and a radio frame number and subframe extracted by the time extraction unit 15 By collating with the number, the reception time in the ONU 5 of the wireless data corresponding to the wireless frame number and subframe number extracted by the number extraction unit 13 is searched from the reception time extracted by the time extraction unit 15, A time estimation unit 16 that calculates the reception time as an estimated value of the reception time. As described above, in the first embodiment, since the radio uplink scheduling information includes the radio frame number and the subframe number of the radio data, the OLT 4 searches for the reception time at the ONU 5 based on these numbers. Since the ONU reception time can be estimated based on the reception time, the ONU reception time can be acquired easily and accurately with a simple process.

Embodiment 2. FIG.
In the first embodiment, the case where the radio uplink scheduling information from the master station device 1 includes a radio frame number and a subframe number is shown, but in the second embodiment, the radio uplink scheduling information is A case will be described in which the slave station device 2 includes information on reception time at which wireless data is received from the UE 3.

  FIG. 3 is a configuration diagram showing the configuration of the optical communication system according to the second embodiment. In FIG. 3, the configuration of the ONU 5 is the same as the configuration of the ONU 5 in FIG. On the other hand, the configuration of the OLT 4 is different from that of the OLT 4 in FIG. Specifically, in FIG. 3, a time extraction unit 30 and a time correction unit 31 are provided instead of the number extraction unit 13 and the time estimation unit 16 in FIG. Further, instead of the time conversion unit 18 of FIG. 1, a time conversion unit 18A is provided in FIG. In FIG. 3, other configurations of the OLT 4 are the same as those in FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted here.

  The time extraction unit 30 extracts the reception time when the slave station device 2 receives the radio data from the UE 3 from the radio uplink scheduling information extracted by the radio information extraction unit 11. The reception time here is expressed in absolute time. Hereinafter, the reception time is referred to as slave station reception absolute time.

  The time correction unit 31 corrects the slave station reception absolute time based on the slave station reception absolute time extracted by the time extraction unit 30 and the subframe head time extracted by the time extraction unit 15 to turn ONU reception time The ONU reception time correction value for obtaining the above is calculated.

  The time conversion unit 18A includes a slave station reception absolute time from the time extraction unit 30, a current local time managed by the OLT 4, an absolute time from the GPS extraction unit 14, and a time correction value from the time correction unit 31. Is entered. The time conversion unit 18A corrects the slave station reception absolute time using the ONU reception time correction value, thereby obtaining an estimated value of the reception time at which the ONU 5 receives wireless data from the slave station device 2 as the ONU reception time. Next, based on the current local time managed by the OLT 4 and the absolute time from the GPS extraction unit 14, the time conversion unit 18A converts the ONU reception time expressed in absolute time into the local time, Output as ONU data reception timing.

In the second embodiment, the time extraction unit 30, the time correction unit 31, and the time conversion unit 18A transmit data corresponding to the radio uplink scheduling information on the terminal side based on the reception time extracted by the time extraction unit 15. The estimated time calculation part which calculates ONU reception time which is the estimated reception time which ONU5 which is an apparatus receives from the substation apparatus 2 is comprised.
The time extraction unit 30 constitutes a slave station time extraction unit that extracts a slave station reception time from the radio uplink scheduling information.
The time correction unit 31 constitutes a time correction unit that obtains a difference time between the reception time extracted by the time extraction unit 15 and the slave station reception time and outputs the difference time as a time correction value.
Further, the time conversion unit 18A constitutes a time calculation unit that calculates the ONU data reception timing indicating the estimated reception time by correcting the slave station reception time based on the time correction value.

  Next, the operation will be described. The basic operation is the same as in the first embodiment. Below, only operation | movement of the time extraction part 30, the time correction | amendment part 31, and the time conversion part 18A is demonstrated.

  Next, an optical uplink scheduling process to the ONU 5 according to the second embodiment will be described.

  From the master station device 1, downlink data including radio uplink scheduling information is transmitted to the OLT 4. In the OLT 4, the received downlink data is input to the wireless information extraction unit 11. The radio information extraction unit 11 extracts a radio main signal and radio uplink scheduling information from downlink data. In the radio uplink scheduling information, as shown in FIG. 4, the absolute time of data reception in the slave station device 2 is stored as the slave station reception timing for each slave station device 2 and for each UE 3, and as the allocation resource, RIV and MCS are stored.

  The radio uplink scheduling information extracted by the radio information extraction unit 11 is output to the resource conversion unit 12 and the time extraction unit 30. The time extraction unit 30 extracts the slave station reception absolute time for each slave station device 2 and for each UE 3 from the radio uplink scheduling information. The extracted slave station reception absolute time is output to the time correction unit 31. The time correction unit 31 predicts the subframe head time several cycles ahead from the subframe head time notified from the ONU 5 and the time length of one subframe. Next, the time correction unit 31 compares the predicted subframe head time of several cycles ahead with the slave station reception absolute time from the time extraction unit 30, and determines the maximum subframe that does not exceed the slave station reception absolute time. The difference time between the head time and the slave station reception absolute time is calculated as an ONU reception time correction value. Here, the time length of one subframe is a system setting value, for example, 1 ms in the case of LTE. In addition, here, although it has been described as several cycles ahead, this may be one cycle ahead in order to provide a time margin in the processing. The ONU reception time correction value calculated by the time correction unit 31 is notified to the time conversion unit 18A.

  In the time conversion unit 18A, first, the ONU reception time correction value is added to correct the slave station reception absolute time, thereby obtaining the ONU reception time at which the ONU 5 receives data from the slave station device 2. Next, the time conversion unit 18A converts the obtained ONU reception time into the local time from the current local time managed by the OLT 4 and the absolute time from the GPS extraction unit 14, and outputs it as the ONU data reception timing. The ONU data reception timing is notified to the PON scheduler 19. On the other hand, the resource conversion unit 12 calculates the uplink data amount from the allocated resource included in the radio uplink scheduling information and notifies the PON scheduler 19 of the uplink data amount. In the PON scheduler 19, the optical uplink for each ONU 5 is taken into account from the ONU data reception timing converted to the local time and the uplink data amount for each slave station device 2 and UE 3, and also including the round-trip delay time between the OLT 4 and the ONU 5 Scheduling is performed and the MPCP unit 17 is notified. Since the processing of the PON scheduler 19 is the same as the processing described in the first embodiment, detailed description thereof is omitted here. The MPCP unit 17 generates a Gate frame based on this optical uplink scheduling information and notifies the ONU 5 of it.

  As described above, also in the second embodiment, as in the first embodiment, the SUBFRAME. By receiving the indication frame and notifying the reception time of the frame to the OLT 4, processing delay in the master station device 1, slave station device 2, ONU 5, OLT 4, and between the slave station device 2 and the ONU 5, The OLT 4 can accurately grasp the reception time at the ONU 5 including the deviation caused by the transmission delay between the station apparatus 1 and the OLT 4. Thereby, resource allocation for reducing the radio data storage time in the ONU 5 becomes possible, and the radio uplink scheduling information for each UE 3 and each slave station device 2 managed by the master station device 1 and the optical uplink scheduling information in the PON are stored. Can be matched exactly. As described above, in the first embodiment, in the wireless communication, the OLT 4 accurately grasps the reception time of the data from the slave station device 2 in the ONU 5, thereby suppressing the uplink data transmission delay time. Enable.

  Further, in the second embodiment, even when the timing information included in the radio uplink scheduling information is the slave station reception absolute time, the radio uplink for each UE 3 and each slave station device 2 managed by the master station device 1 is performed. The scheduling and the optical uplink scheduling information in the PON are transferred to the SUBFRAME. By accurately matching by receiving the indication frame and notifying the information to the OLT 4, it is possible to perform resource allocation with reduced radio data storage time in the ONU 5, and to reduce the uplink delay time.

  DESCRIPTION OF SYMBOLS 1 Master station apparatus, 2 Slave station apparatus, 3 Radio | wireless terminal (UE), 4 Optical subscriber termination apparatus (OLT), 5 Optical network unit (ONU), 6 Optical transmission line, 7 GPS receiver, 11 Radio | wireless information extraction part , 12 Resource conversion unit, 13 Number extraction unit, 14 GPS extraction unit, 15 Time extraction unit, 16 Time estimation unit, 17 MPCP unit, 18 Time conversion unit, 19 PON scheduler, 20 MUX, 21 Optical transmission / reception unit, 22 Number extraction Unit, 23 GPS extraction unit, 24 time detection unit, 25 frame generation unit, 26 MPCP unit, 27 transmission control unit, 28 optical transmission / reception unit, 29 MUX.

Claims (3)

A station side device connected to the master station device;
A terminal-side device connected to a slave station device that performs wireless communication with the terminal;
An optical transmission line connecting the station side device and the terminal side device,
The terminal side device
A reception time detecting unit that receives wireless data transmission timing information indicating transmission timing at which the terminal transmits wireless data from the slave station device, and detects a reception time at which the wireless data transmission timing information is received;
A transmission unit that transmits a notification frame that notifies the station side device of the reception time, and
The station side device
A radio information extraction unit that extracts radio uplink scheduling information managed by the master station device;
A time extraction unit for extracting the reception time from the notification frame transmitted by the transmission unit;
Based on the reception time extracted by the time extraction unit, an estimated time calculation unit that calculates an estimated reception time at which the terminal-side device receives data corresponding to the radio uplink scheduling information from the slave station device;
A scheduling unit that generates optical uplink scheduling information for performing data transmission from the terminal-side device to the station-side device based on the estimated reception time and the radio uplink scheduling information;
A notification unit for notifying the optical uplink scheduling information to the terminal side device,
Optical communication system. The radio uplink scheduling information includes a radio frame number and a subframe number of the radio data,
The notification frame includes the reception time, a radio frame number and a subframe number of the radio data corresponding to the reception time,
The estimated time calculation unit
A first number extraction unit for extracting the radio frame number and the subframe number from the radio uplink scheduling information;
A second number extraction unit for extracting the radio frame number and the subframe number from the notification frame;
The time extraction unit by collating the radio frame number and the subframe number extracted by the first number extraction unit with the radio frame number and the subframe number extracted by the second number extraction unit. The reception time corresponding to the radio frame number and the subframe number extracted by the first number extraction unit is searched from the reception times of the notification frame extracted by the reception frame, and the reception obtained by the search A time estimation unit that outputs time as the estimated reception time,
The optical communication system according to claim 1. The radio uplink scheduling information includes information on a slave station reception time at which the slave station apparatus receives radio data corresponding to the radio uplink scheduling information from the terminal,
The estimated time calculation unit
A slave station time extraction unit that extracts the slave station reception time from the radio uplink scheduling information;
A time correction unit for obtaining a difference time between the reception time extracted by the time extraction unit and the slave station reception time, and outputting the difference time as a time correction value;
A time calculation unit that calculates the estimated reception time by correcting the slave station reception time based on the time correction value,
The optical communication system according to claim 1.

Images