JP2019050449A - Band unused period detecting device, subscriber line terminal device, and band unused period detecting method - Google Patents

Abstract

To detect a band unused period of an upstream signal at an arbitrary timing.SOLUTION: A band unused period detecting method includes: acquiring linkage information used when an optical transmission system performs bandwidth allocation; arranging information indicating a period assigned to transmission of a signal obtained from acquired cooperation information in time series on a time axis to make a transmission period pattern of the signal; dividing the time axis on the basis of a length of a frame used in a time division duplex system; creating a data set by overlaying the divided time axes; detecting information about a frame format corresponding to a data set on the basis of the generated data set and information of a plurality of frame formats of a predetermined time division duplex system; calculating a band unused period in the optical transmission system on the basis of the information about the detected frame format; and calculating a period for allocating a band in a band unused period on the basis of the reference time obtained from the cooperation information acquired first and the calculated bandwidth unused period information.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a band unused period detection device, a subscriber line terminal device, and a band unused period detection method.

  There is a method in which an RRH (Remote Radio Head) which is an antenna unit of a radio base station and a BBU (Base Band Unit) which is a signal processing unit are separately installed. In this method, for example, a communication system 1000 as shown in FIG. 10 is applied. The communication system 1000 includes a BBU 700, RRHs 701 and RRHs 702, and optical devices 600, 601, and 602. The BBU 700, the RRH 701, and the RRH 702 are connected to the optical devices 600, 601, and 602 that perform optical communication. Further, each of the optical devices 601 and 602 and the optical device 600 are connected by the optical fibers 901 and 902.

  Each of the RRHs 701 and 702 forms a small cell 801 and 802, and performs wireless communication with wireless terminal devices 851 and 852 present in the small cell 801 and 802. The RRHs 701 and 702 transmit the signals received from the terminal devices 851 and 852 to the BBU 700 via the optical device 600, and transmit the signals transmitted by the BBU 700 to the terminal devices 851 and 852.

  In the communication system 1000, a section of optical communication is called a mobile front hall (MFH). Uplink and downlink signals can be simultaneously transmitted and received on a single optical fiber by using the Wavelength Division Multiplexing (WDM) method using different wavelengths in uplink and downlink for the mobile front hole (For example, refer to nonpatent literature 1).

  Frequency Division Duplex (FDD) method and Time Division Duplex method (Time Division Duplex method) are used as RRHs 701 and 702 as radio communication with terminal devices 851 and 852 in small cells 801 and 802. : Two systems of TDD) are used. The FDD system is a system using different frequency bands in uplink and downlink, and the TDD system is a system using frequency bands shared by the uplink and downlink and signals orthogonal to each other on the time axis.

  For example, in LTE (Long Term Evolution), seven types of TDD frame formats having different ratios of uplink and downlink signals, which are used when applying the TDD scheme, are defined. By switching and applying this frame format in accordance with uplink and downlink traffic, it is possible to flexibly set the ratio of uplink and downlink communication time (for example, see Non-Patent Document 2). ).

  FIG. 11 is a diagram showing a transmission state of data in a wireless section and an optical section in the case of accommodating a TDD wireless base station in the mobile front hall. The distribution chart of FIG. 11 (A) shows the transmission state of data in the wireless section, and the distribution chart of FIG. 11 (B) shows the transmission states of uplink and downlink data of the optical section. Sections indicated by symbols D1, D2 and D3 are sections in which a downlink signal (hereinafter referred to as "downlink signal") is transmitted, and sections indicated by reference symbols U1 and U2 are uplink signals (hereinafter referred to as "uplink signal") Section) is being transmitted.

  As shown in FIG. 11, in the wireless section, data is transmitted orthogonally to the uplink and downlink on the time axis, so only one of the upstream signal and the downstream signal is transmitted at any time. become. Also in the light section, the orthogonal relationship on the time axis is maintained and transmitted. Therefore, when the WDM system is applied in the light section and different wavelengths are applied to the upper and lower links, a period in which data transmission is not performed at each wavelength, that is, a period in which the band is unused occurs. In the following description, a band unused period is described as a TDD untransmitted period, and a period in which a band is used is described as a TDD transmission period.

  For example, as shown in FIG. 11B, when the wavelength λ1 is applied to the downlink and the wavelength λ2 is applied to the uplink, in the wavelength λ1, TDD untransmitted period is between t1 to t2 and t3 to t4. Become. Further, in the wavelength λ2, TDD non-transmission period is from t0 to t1, t2 to t3, and t4 to t5.

  There is known a technology for accommodating the above-described mobile front hall by PON (Passive Optical Network) (see, for example, Patent Documents 1, 2 and Non-Patent Document 3). FIG. 12 is a block diagram showing an example of a communication system 1000a in which the mobile front hall is accommodated by PON. In the communication system 1000 a, each of the RRHs 701, 702, 703 is connected to an ONU (Optical Network Unit: subscriber line termination device) 611, 612, 613.

  The BBU 700 is connected to an OLT 610 (Optical Line Terminal: subscriber line terminal equipment). Each of the ONUs 611, 612, 613 is connected to the optical fibers 901, 902, 903, and the OLT 610 is connected to the optical fiber 900. The optical fiber 900 and the optical fibers 901, 902 and 903 are connected by an optical splitter 950.

  For example, in a state where the ONUs 611 to 613 are connected to the OLT 610, the ONU 619 may newly request a connection. When the OLT 610 in operation accommodates the ONU 619 that requests a new connection, a process called activation is performed. When processing the activation, as shown in FIG. 13, the OLT 610 provides a period called a discovery window. In FIG. 13, only the ONU 611 explicitly shows the ONU connected to the OLT 610.

  The discovery window period is an acceptance period of a new connection request, and the ONU 619 requesting a new connection can transmit a new connection request frame 699 -new to the OLT 610 during the discovery window. When the OLT 610 receives the new connection request frame 699-new, it authenticates and registers the ONU 619 that has transmitted the new connection request frame 699-new. The discovery window is provided every designated cycle, for example, once every 100 ms (milliseconds), once every 10 seconds, etc.

International Publication No. 2014/077168 Unexamined-Japanese-Patent No. 2016-146585

"Basic Technology Course [GE-PON Technology], 1st PON" ", NTT Technical Journal, [online], 2005, Nippon Telegraph and Telephone Corporation, [September 7, 2017 search], Internet <URL Http://www.ntt.co.jp/journal/0508/files/jn200508071.pdf> 3GPP, "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 12)", 3GPP TS 36.300 (V 12.4.0), December 2014 Daisuke Hisano, Takayuki Kobayashi, Member, IEEE, Hiroshi Ou, Tatsuya Shimada, Hiroyuki Uzawa, Jun Terada, and Akihiro Otaka, “TDM-PON for Accommodating TDD-Based Fronthaul and Secondary Services”, JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 35, NO. 14, JULY 15, 2017, pp2788-2796

  However, while the discovery window is being performed, connected ONUs 611-613 are not given the opportunity to transmit upstream signals. For example, FIG. 13 is a diagram showing a transmission state of an uplink frame in PON. The reference numerals 691-1 to 3 indicate upstream frames transmitted by the ONU 611, the reference numerals 692-1 to 3 indicate upstream frames transmitted by the ONU 612, and the reference numerals 693-1 to 3 The upstream frame transmitted by the ONU 613 is shown.

  As shown in FIG. 13, when the discovery window is provided in the second uplink transmission cycle T, the ONU 611 is not given an opportunity to transmit an uplink frame. Therefore, the ONU 611 queues the frame 691-2 in the transmission buffer, and the frame is accumulated in the ONU 611. As a result, a delay occurs in the ONU 611, and there is a problem that the requirement for the delay in the communication between the RRH 701 to which the ONU 661 connects and the BBU 700 can not be satisfied.

  In order to solve this problem, for example, as shown in FIG. 14, the downlink period of t0 to t1, t2 to t3 and t4 to t5 radio sections in FIG. It is conceivable to provide a discovery window in the TDD untransmitted period of In the case of this method, in order to provide a discovery window in TDD non-transmission periods, means for determining TDD non-transmission periods and TDD transmission periods are needed. For example, Patent Document 2 and Non-Patent Document 3 disclose means for detecting a TDD non-transmission period using a traffic monitor. Note that, in FIG. 14, only the ONU 611 explicitly shows the ONU connected to the OLT 610.

  However, in the method disclosed in Patent Document 2, the TDD non-transmission period is estimated based on the traffic volume acquired by the traffic monitor using the periodicity of traffic generation. Therefore, there is a problem that it is not possible to accurately detect the TDD unsent period if there is no traffic to a certain extent.

  Further, in the method disclosed in Non-Patent Document 3, the TDD non-transmission period is estimated using the test pattern of the uplink signal. Therefore, there is a problem that the TDD non-transmission period can not be detected if the test pattern can not be transmitted, for example, if the administrator can not transmit the test pattern immediately because of operation or the like. is there.

  In view of the above circumstances, the present invention aims to provide a technique capable of detecting a band unused period of an uplink signal at an arbitrary timing.

  One aspect of the present invention is a subscriber line termination device connected to a terminal device and a communication device for performing communication according to a time division duplex system, and a subscriber line termination station connected to the subscriber line termination device via an optical fiber Communication system in which an optical transmission system including an apparatus, in which an upstream optical signal and a downstream optical signal are multiplexed at different wavelengths, relays communication between the upper apparatus connected to the subscriber line terminal apparatus and the communication apparatus A band unused period detection device used for the link information generated based on scheduling information of a signal transmitted / received between the upper level apparatus and the communication apparatus; The cooperation information to be used when performing the process is acquired, and the information indicating the period allocated to the transmission of the signal obtained from the acquired cooperation information is arranged in time series on the time axis to transmit the signal transmission period patter A data set generation unit for dividing the time axis based on the length of a frame used in the time division duplex system and superposing the divided time axes to generate a data set; A frame format detection unit for detecting information on the frame format corresponding to the data set based on information of a plurality of frame formats of the time division duplex system to be determined; and the frame detected by the frame format detection unit An unused period calculation unit that calculates a band unused period in the optical transmission system based on information on a format, a reference time obtained from the cooperation information initially acquired by the data set generation unit, and the unused period Based on the information on the band unused period calculated by the calculating unit, the period for allocating the band in the band unused period is calculated. A registration period calculation unit for outputting to said line termination with a band unused period detecting device comprising a.

  One embodiment of the present invention is the above-mentioned band unused period detection device, wherein the registration period calculating unit generates the data set when the unused period calculating unit calculates the band unused period of an uplink signal. When a period allocated to transmission of the uplink signal obtained from the new cooperation information acquired by the unit is included in the band unused period of the uplink signal, a period for allocating a band in the band unused period of the uplink signal When the unused period calculation unit calculates the band unused period of the downlink signal, the data set generation unit is allocated for transmission of the downlink signal obtained from the new cooperation information acquired. When the period during which the current signal is received is included in the band unused period of the downlink signal, the calculation of the period for allocating the band in the band unused period of the downlink signal is ended.

  One embodiment of the present invention is the band unused period detection device described above, wherein the frame format detection unit is assigned to a transmission pattern of an uplink signal included in the data set and an uplink signal of the frame format. Calculation method for performing cross correlation calculation based on period pattern, cross correlation calculation based on the transmission pattern of the downlink signal included in the data set and the pattern of the period allocated to the frame format downlink signal Calculation method for performing cross correlation calculation based on the transmission patterns of the upstream signal and the downstream signal included in the data set and the pattern of the period allocated to the upstream signal and the downstream signal of the frame format Information about the frame format corresponding to the data set is detected by performing any of the calculation methods of That.

  One embodiment of the present invention is the band unused period detection device described above, wherein the data set generation unit includes the uplink signal included in the cooperation information as information indicating a period allocated for transmission of the signal. The allocation start time of the link is acquired, and the acquired allocation start time of the uplink signal is arranged in time series on the time axis, or the cooperation information is acquired as information indicating a period allocated to transmission of the signal. The acquired time is acquired as the time allocated to the downlink signal, and the acquired times allocated to the downlink signal are arranged in time series on the time axis, or the allocation start time of the uplink signal and the downlink The time assigned to the signal is arranged in time series on the time axis.

  One embodiment of the present invention is the above-mentioned band unused period detection device, wherein the optical transmission system is a PON system, and the unused period calculation unit uses the frame format detected by the frame format detection unit. The band unused period of the upstream signal in the PON system is calculated, and the registration period calculation unit receives a new connection request transmitted by the subscriber line termination device newly connected to the PON system. The new connection request reception period to be registered is calculated based on the reference time and the band unused period of the uplink signal calculated by the unused period calculation unit, and the information on the calculated new connection request reception period is calculated. It outputs to the said subscriber line terminal device.

  One aspect of the present invention is a subscriber line termination device connected to a terminal device and a communication device for performing communication according to a time division duplex system, and a subscriber line termination station connected to the subscriber line termination device via an optical fiber Communication system in which an optical transmission system including an apparatus, in which an upstream optical signal and a downstream optical signal are multiplexed at different wavelengths, relays communication between the upper apparatus connected to the subscriber line terminal apparatus and the communication apparatus Subscriber line terminal station apparatus used for the connection information, which is cooperation information generated based on scheduling information of signals transmitted and received between the upper level apparatus and the communication apparatus, wherein the optical transmission system assigns a band The cooperation information to be used when performing the acquisition is acquired, and the information indicating the period allocated to the transmission of the signal obtained from the acquired cooperation information is arranged in time series on the time axis to be the transmission period pattern of the signal. A data set generation unit configured to divide the time axis based on the length of a frame used in the time division duplex system and overlap the divided time axes to generate a data set; A frame format detection unit for detecting information on the frame format corresponding to the data set based on information on a plurality of frame formats of the time division duplex system, and the frame format detected by the frame format detection unit An unused period calculation unit that calculates a band unused period in the optical transmission system based on information, a reference time obtained from the linkage information initially acquired by the data set generation unit, and the unused period calculation unit Calculate a period for allocating a band in the band unused period based on the information of the band unused period calculated by A recording period calculation unit, based on the duration for allocating the bandwidth the registration period calculation unit calculates a Line Termination comprising a bandwidth allocation process unit, the performing band allocation.

  One embodiment of the present invention is the above-mentioned subscriber line terminal station apparatus, wherein, when the band allocation processing section allocates the band of the upstream signal, the above-mentioned obtained from the cooperation information acquired anew When the period allocated for transmission of the uplink signal is included in the period for allocating the band in the uplink direction, or when the band allocation for the downlink signal is performed, the newly acquired cooperation information The allocation of the bandwidth is ended when the obtained allocated period for the transmission of the downlink signal is included in the period for allocating the bandwidth in the downlink direction.

  One aspect of the present invention is a subscriber line termination device connected to a terminal device and a communication device for performing communication according to a time division duplex system, and a subscriber line termination station connected to the subscriber line termination device via an optical fiber Communication system in which an optical transmission system including an apparatus, in which an upstream optical signal and a downstream optical signal are multiplexed at different wavelengths, relays communication between the upper apparatus connected to the subscriber line terminal apparatus and the communication apparatus A method for detecting a band unused period performed in step (b), wherein the optical transmission system assigns a band according to cooperation information generated based on scheduling information of a signal transmitted / received between the upper apparatus and the communication apparatus. The cooperation information to be used when performing the acquisition is acquired, and the information indicating the period allocated for transmission of the signal obtained from the acquired cooperation information is arranged in time series on the time axis to transmit the transmission period of the signal. The time axis is divided based on the length of a frame used in the time division duplex system, the divided time axes are superimposed to generate a data set, and the generated data set is determined in advance. Information related to the frame format corresponding to the data set is detected based on information of a plurality of frame formats of the time division duplex system, and based on the detected information A band in which a band unused period is calculated, and a band allocation period in the band unused period is calculated based on the reference time obtained from the cooperation information acquired first and the calculated band unused period information. It is an unused period detection method.

  According to the present invention, it is possible to detect a band unused period of an uplink signal at any timing.

It is a block diagram showing a communication system in a 1st embodiment. It is a figure which shows the zone | band allocation start time in 1st Embodiment. It is a block diagram which shows the internal structure of OLT in 1st Embodiment, and the connection relation of OLT, a cooperation connection apparatus, and BBU. It is a figure which shows the table of the TDD frame format in 1st Embodiment. It is a flowchart which shows the flow of a process of the zone | band unused period detection apparatus in 1st Embodiment. It is a figure which shows the production | generation process of the data set in 1st Embodiment. It is a flowchart (the 1) which shows exception processing in a 1st embodiment. It is a flowchart (the 2) which shows exception processing in a 1st embodiment. It is a block diagram which shows the internal structure of OLT in 2nd Embodiment, and the connection relation of OLT, a cooperation connection apparatus, and BBU. It is a block diagram showing an example of composition of a mobile front hall. It is a figure which shows the transmission state of the upstream signal and downstream signal in a mobile front hall. It is a block diagram which shows an example of the structure which applied PON in the optical transmission system of a mobile front hole. FIG. 10 is a diagram (1) illustrating an influence on a transmission by a discovery window. It is a figure (the 2) which shows the influence on transmission by a discovery window.

First Embodiment
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a communication system 1 in the first embodiment. The communication system 1 applies a PON system as a mobile front hall, and the PON system is configured to relay communication between the BBU 200 and the RRHs 210-1 to RRH 210-N.

  The PON system includes an OLT 100, ONUs 110-1 to 110-N, an optical splitter 120, an optical fiber 130, and optical fibers 131-1 to 131-N. The optical splitter 120 is an optical multiplexer / demultiplexer that connects the optical fiber 130 and the optical fibers 131-1 to 131 -N. The optical splitter 120 demultiplexes the signal transmitted from the OLT 100, and demultiplexes the demultiplexed signal to all of the ONUs 110-1 to 110-N connected via the optical fibers 131-1 to 131-N. Output. In addition, the optical splitter 120 multiplexes the signals transmitted from the ONUs 110-1 to 110-N, and outputs the multiplexed signal to the OLT 100. The optical fiber 130 connects the OLT 100 and the optical splitter 120. The optical fibers 131-1 to 131 -N connect the optical splitter 120 to the ONUs 110-1 to 110 -N.

The OLT 100 is a subscriber line terminal device that terminates the ONUs 110-1 to 110-N. The downstream signal transmitted by the OLT 100 is demultiplexed by the optical splitter 120 and reaches all ONUs 110-1 to 110-N.
The ONUs 110-1 to 110-N are subscriber line termination devices. Each of the ONUs 110-1 to 110-N takes in data addressed to its own device, and outputs the taken-in data to each of the RRHs 210-1 to 210-N connected thereto. The upstream signals transmitted by the ONUs 110-1 to 110-N are multiplexed by the optical splitter 120 and reach the OLT 110.

The BBU 200 corresponds to the signal processing unit of the radio base station, and corresponds to a higher-level device in the communication system 1. The BBU 200 connects to the OLT 100.
RRHs 210-1 to 210-N correspond to the antenna units of the radio base station. The RRHs 210-1 to 210-N are, for example, TDD communication devices. Each of the RRHs 210-1 to 210-N is connected to the ONUs 110-1 to 110-N. Each of RRHs 210-1 to 210-N forms small cells 300-1 to 300-N, and a terminal device 400-1-1 transmits and receives radio signals present in the formed small cells 300-1 to 300-N. Radio signals are transmitted and received according to the TDD scheme with .about.400-N-1. A plurality of terminal devices 400-1-1 to 400 -N-1 may exist in each of the small cells 300-1 to 300 -N.

  The ONU 110-new connected by the RRH 210-new is in a state of newly making a connection request to the OLT 100. That is, the ONU 110 -new is physically connected to the OLT 100 via the optical fiber 131 -new connected to the optical splitter 120, but is in a state of being authenticated by the OLT 100 and not registered.

  In a general PON communication method, for upstream signals from ONUs 110-1 to 110-N to OLT 100, for example, a method called Dynamic Bandwidth Allocation (DBA) is used to allocate a band for each of ONUs 110-1 to 110-N. It is used. In the DBA, each of the ONUs 110-1 to 110-N first notifies the OLT 100 of the amount of upstream data. The OLT 100 is performed in the procedure of allocating the transmission time and the transmission permission amount for each of the ONUs 110-1 to 110-N based on the notification.

  The downstream signals from the OLT 100 to the ONUs 110-1 to 110-N are transmitted at one time because the OLT 100 transmits data including each data of the ONUs 110-1 to 110-N in one frame in a time division multiplexing scheme. It does not take so much time. On the other hand, for the upstream signal, since the OLT 100 receives the notification by the above-mentioned DBA, a lot of time is required for the transmission time to allocate the band. For this reason, it is considered difficult to satisfy the requirement for the delay between the BBU 200 and the RRHs 210-1 to 210-N for the upstream signal.

  When the technology described in Patent Document 1 described above is applied, the BBU 200 performs uplink signal scheduling from the RRHs 210-1 to 210 -N to the BBU 200 in advance in order to satisfy the requirement. The BBU 200 generates and outputs scheduling information including information on radio resources to be allocated to the RRHs 210-1 to 210-N by the scheduling.

  The OLT 100 uses the information on the scheduling to obtain the allocation start time and the allocation data amount of the upstream signal band to the ONUs 110-1 to 110-N in the PON section. Here, the band allocation start time is, for example, as shown in FIG. 2, when the RRH 210-i is connected to the ONU 110-i (i is an arbitrary number of 1 to N), the RRH 210 This is the time at which the wireless signal received by -i is collectively demodulated and output to the ONU 110-i is started.

  The allocation start time and the allocation data amount of the upstream signal can be determined without waiting for the notification from the ONUs 110-1 to 110-N by the OLT 100 obtaining the allocation start time and the allocation data amount of the upstream signal band. Therefore, the delay time for the upstream signal can be shortened, and the requirement for the delay between the BBU 200 and the RRHs 210-1 to 210-N can be satisfied.

  In the present embodiment, the technology described in Patent Document 1 is cooperation information used for cooperation of processing between the BBU 200 and the OLT 100, and uses cooperation information generated based on scheduling information. The cooperation information is information including the allocation start time of the uplink signal and the allocation data amount.

  FIG. 3 is a block diagram showing the internal configuration of the OLT 100, the connection relationship between the OLT 100 and the BBU 200, and the connection relationship between the OLT 100 and the BBU 200 and the cooperation connection device 180. In FIG. 3, the solid line indicates the transmission path of the control signal, the dotted line indicates the transmission path of the downstream signal, and the one-dot broken line indicates the transmission path of the upstream signal.

  As described above, BBU 200 schedules uplink signals from RRHs 210-1 to 210-N to BBU 200 in advance, generates scheduling information, and outputs the generated scheduling information to cooperative access apparatus 180. Further, the BBU 200 includes an interface (hereinafter referred to as “IF” (Interface)) 200i-u for receiving an upstream signal, and an IF 200i-d for transmitting a downstream signal, and the IF 200i-u and the IF 200i-d are Respectively connected to the IF 70i-1 and the IF 71i-1 of the OLT.

  The cooperative connection apparatus 180 converts the scheduling information output by the BBU 200 into the information of the allocation start time and the allocation data amount of the upstream signal for each of the ONUs 110-1 to 110-N, and generates the cooperative information. Further, the cooperation connection device 180 outputs the generated cooperation information to the OLT 100 via the IF 80 of the OLT 100.

  The OLT 100 includes a band unused period detection device 10, a band allocation processing unit 30, a downstream frame processing unit 40, an upstream frame processing unit 50, an E / O (Electrical / Optical) conversion unit 61, and an O / E (Optical / Electrical) conversion. A section 62, L2SW (Layer 2 Switch) 70, 71, and IF (Interface) 70i-1, 71i-1, 80 are provided.

  The band unused period detection apparatus 10 includes a data set generation unit 11, a frame format detection unit 12, a storage unit 13, an unused period calculation unit 14, and a registration period calculation unit 15. The data set generation unit 11 acquires the cooperation information output by the cooperation connection device 180 via the IF 80. Further, the data set generation unit 11 reads out the allocation start time of the uplink signal included in the acquired cooperation information. Further, the data set generation unit 11 outputs the information on the reference time to the registration period calculation unit 15 with the allocation start time of the uplink signal included in the first cooperation information as the reference time.

  In addition, the data set generation unit 11 sets the reference time as the initial value of the time axis, and arranges the read out upstream signal allocation start time in time series on the time axis. Further, the data set generation unit 11 divides the time axis on the basis of the length of a radio frame used in the TDD method, and generates a data set by superposing the divided time axes. As a result, in the data set generated by the data set generation unit 11, the pattern of the transmission period of the uplink signal is indicated in the radio frame.

  The storage unit 13 stores, for example, a table shown in FIG. 4 in advance. The table shown in FIG. 4 is a table for storing information of seven types of TDD frame formats having different uplink and downlink ratios, which is used when applying the TDD scheme. Seven types of TDD frame formats are defined in Non-Patent Document 2. The information in the TDD frame format includes items of “index”, “switching period”, and “subframe number”. In the item of "index", numbers 0 to 6 indicating seven types of TDD frames are written. The “switching cycle” represents the repetition cycle of the upper and lower link ratio, and for example, either “5 ms” or “10 ms” is written to the switching cycle.

  The item "subframe number" is divided into 10 items from 0 to 9, and "D", "U", and "S" which are information of types for each TDD subframe obtained by dividing a TDD frame. Any information is written. “D” indicates a downlink subframe, ie, a subframe in which a downlink signal is transmitted. “U” indicates an uplink subframe, ie, a subframe in which an uplink signal is transmitted. “S” is a special subframe and is a frame including a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS).

  As for the "index", special subframes "S" are inserted every 5 ms as "switching period" for 0, 1, 2 and 6 and for "index" 3, 4 and 5 , Special subframe “S” is inserted every 10 ms as “switching cycle”.

  In the case of LTE, as shown in Non-Patent Document 2, the length of one TDD subframe is defined as 1 ms, and one subframe is set as the minimum time unit of scheduling. This unit is indicated as TTI (Transmission Time Interval). For example, a period until one TTI elapses from the band allocation start time described with reference to FIG. 2 is defined as an uplink TDD transmission period.

  The frame format detection unit 12 calculates the cross correlation based on the transmission period pattern of the uplink subframe of the data set generated by the data set generation unit 11 and the TDD frame format stored in the storage unit 13 . Further, the frame format detection unit 12 outputs information on the TDD frame format having the highest degree of similarity, based on the correlation coefficient value obtained by the cross-correlation operation.

  The unused period calculation unit 14 calculates the period of “D” based on the information on the TDD frame format output from the frame format detection unit 12 and the TDD frame format stored in the storage unit 13, that is, in the downlink subframe. Calculate the period. Further, the unused period calculation unit 14 outputs the calculated downlink subframe period as an uplink TDD non-transmission period, that is, an uplink signal band unused period.

  The registration period calculation unit 15 is a period of the activation window based on the information on the band unused period of the uplink signal output from the unused period calculation unit 14 and the information on the reference time output from the data set generation unit 11. Is calculated, and information on the calculated activation window period is output to the band allocation processing unit 30. The activation window has the same meaning as the discovery window described in the background art, and thus the detailed description is omitted.

  The band allocation processing unit 30 acquires cooperation information output by the cooperation connection apparatus 180 via the IF 80, and information on the allocation start time and allocation data amount of upstream signals for each of the ONUs 110-1 to 110-N from the acquired cooperation information. Read out. The band allocation processing unit 30 calculates the actual transmission permission amount of the uplink frame based on the read allocation data amount. Also, the band allocation processing unit 30 uses the allocation start time as the transmission start time, generates a transmission permission frame including the transmission start time and the calculated transmission permission amount, and generates the generated transmission permission frame via the downlink frame processing unit 40. It transmits to ONU110-1-110-N.

  Further, the band allocation processing unit 30 generates a frame including information on the period of the activation window output by the registration period calculation unit 15, and transmits the generated frame to the downstream frame processing unit 40.

  The E / O conversion unit 61 is connected to the downlink of the optical fiber 130, converts the downlink electric signal output from the downlink frame processing unit 40 into an optical signal, and outputs the optical signal to the downlink of the optical fiber 130. The O / E conversion unit 62 is connected to the uplink of the optical fiber 130, converts an optical signal in the uplink direction into an electric signal, and outputs the electric signal to the uplink frame processing unit 50.

  The L2SW 70 receives, via the IF 70i-1, downstream data that the BBU 200 transmits to the RRHs 210-1 to 210-N via the IF 70i-1 and outputs the data to the downstream frame processing unit 40. The L2SW 71 outputs, to the BBU 200 via the IF 71i-1, the uplink data that the RRHs 210-1 to 210-N output from the uplink frame processing unit 50 transmit to the BBU 200.

  The downstream frame processing unit 40 multiplexes the downstream data of each of the ONUs 110-1 to 110-N output by the L2SW 70 according to the time division multiplexing method to generate a frame, and generates the generated frame as the E / O converter 61. It transmits to ONU110-1-110-N via it. Also, the downlink frame processing unit 40 transmits the transmission permission frame output from the band allocation processing unit 30 to the ONUs 110-1 to 110-N. Also, the downstream frame processing unit 40 transmits a frame including information on the period of the activation window output by the bandwidth allocation processing unit 30 to the unregistered ONU 110 -new. The unregistered ONU 110 -new receives the frame and transmits a new connection request frame to the OLT 100 during the activation window.

  The upstream frame processing unit 50 receives the upstream frames transmitted by the ONUs 110-1 to 110-N via the O / E conversion unit 62. Also, the upstream frame processing unit 50 divides the received upstream frames into frames for each of the ONUs 110-1 to 110-N, and outputs the frames to the BBU 200 via the L2SW 71.

(Processing by the band unused period detection device)
FIG. 5 is a flow chart showing the flow of processing by the band unused period detection device 10.
The data set generation unit 11 initializes the data set (step S101). The data set generation unit 11 acquires a plurality of pieces of cooperation information output by the cooperation connection device 180 during a predetermined time (step S102).

  When the designated time has elapsed, the data set generation unit 11 reads out the information on the allocation start time of the uplink signal band from the first cooperation information (step S103). The data set generation unit 11 outputs the information of the reference time to the registration period calculation unit 15 with the allocation start time included in the first cooperation information read out as the reference time. Further, the data set generation unit 11 writes the information corresponding to the reference time into the initialized data set to generate a data set (step S104).

  Here, the data set is, for example, data having an array structure indicated by a symbol DS1 shown in FIG. The numbers “0” to “19” at the top of the data set DS1 are the numbers of the sequences. In the case of LTE, 1 TTI, which is the length of one subframe, is 1 ms, and the data set DS1 shown in FIG. 6 has a length of 20 ms, that is, the number of arrays that can store information of 20 subframes. Have. If, in step S102, the time for which the data set generation unit 11 acquires cooperation information is 10 seconds, the required number of data set arrays is 10 s / 1 ms = 10,000.

  The data set DS1 is initialized by the data set generation unit 11 in the process of step S101, that is, the information is not written. In the process of step S104, the data set generation unit 11 writes and stores a value of “1” as a flag at the position of the first array number “0” of the array corresponding to the reference time.

  The data set generation unit 11 reads out the allocation start time of the band of the upstream signal from the next cooperation information (step S105). The data set generation unit 11 calculates the difference between the read allocation start time and the reference time, and writes and stores “1” of the flag in the position of the array of the data set DS1 corresponding to the calculated difference time (step S106). For example, as shown in FIG. 6, when the reference time is t0 = 10 ms and the allocation start time of the second linkage information is t1 = 14 ms, the difference is 4 ms. Therefore, the data set generation unit 11 writes the flag "1" at the position of "4" of the data set DS1.

  The association information may be periodically acquired every one TTI, or may be acquired only randomly. On the other hand, by calculating the relative time difference with the reference time by using the assignment start time included in the cooperation information as described above, it is possible to use upstream signals without depending on the output timing of the cooperation information. A pattern of transmission periods can be recorded.

  The data set generation unit 11 determines whether or not the processing of steps S105 and S106 has been performed for all the acquired cooperation information (step S107). If the data set generation unit 11 determines that the processes of steps S105 and S106 have not been performed for all acquired cooperation information (step S107-NO), the process from step S105 is repeated.

  On the other hand, when the data set generation unit 11 determines that the processes of steps S105 and S106 have been performed for all acquired cooperation information (step S107-YES), the data set DS1 is divided into TDD frame lengths, that is, 10 ms. Superimposing (step S108). For example, as shown in FIG. 6, the data set generation unit 11 divides the data set DS1 into data set DS2-1 and data set DS2-2 in units of 10 ms. The data set generation unit 11 generates the data set DS3 by performing superposition so that the array at the top of the data set DS2-1 and the array at the top of the data set DS2-2 overlap.

  At this time, the data set generation unit 11 sets the value of the array in which the flag is written to “1” and the value of the array in which the flag is not written to “0”, and performs the logical OR operation. The flag "1" is written and stored in the array that has become "1". The finally obtained data set DS3 has a length of 10 ms, which is the same as the TDD frame length. The arrangement in which the flag “1” is written indicates that the transmission period has been allocated to the upstream signal. Since each arrangement indicates a period of 1 ms, the data set DS3 indicates a pattern of transmission periods of uplink signals obtained from a plurality of pieces of association information.

  The data set generation unit 11 outputs the generated data set DS3 to the frame format detection unit 12. The frame format detection unit 12 calculates the cross correlation between the data set DS3 output from the data set generation unit 11 and each of the upstream signal patterns obtained from the TDD frame format stored in the storage unit 13 Calculate relationship figures. The frame format detection unit 12 transmits the index value of the TDD frame format having the largest calculated correlation coefficient value and the subframe number at the beginning of the TDD frame format to the unused period calculation unit 14 as the information on the TDD frame format. It outputs (step S109).

  An example of the cross correlation operation will be described. In the arrangement of the data set DS3, the head is always an upward signal. In order for the frame format detection unit 12 to perform the cross-correlation operation, for example, all of the seven TDD frame formats are rearranged such that the position of “U” is at the beginning and “U” is at the beginning. There is a method of performing cross correlation operation on the pattern of.

  For example, for a TDD frame whose “index” is “3”, since the number of “U” is three, the following three patterns exist as the pattern where “U” is the head. That is, there are three of “UUUDDDDDDS”, “UUDDDDDDDSU”, and “UDDDDDDDSU”. The three leading subframe numbers are “2”, “3”, and “4”.

  The frame format detection unit 12 generates a cross-correlation array in which the position of “U” of the pattern generated from the TDD frame format is “1” and the positions of “D” and “S” are “0”. The arrays for cross correlation for the three patterns of the above index "3" are "1110000000", "1100000001", and "1000000011". The frame format detection unit 12 writes “0” at the position where the value is not written in the array of the data set DS3. For example, in the case of the data set DS3 of FIG. 6, the frame format detection unit 12 sets the data set DS3 as an array of “1001110010”.

  The frame format detection unit 12 generates a cross correlation array for all index values “0” to “6”, performs cross correlation operation with the data set DS3 for each of the generated cross correlation arrays, and generates cross correlations. Calculate the correlation coefficient value for each array. By performing this cross correlation operation, the correlation coefficient value of the cross correlation array in which the number of positions where the position of the flag “1” of the data set DS3 coincides with the position of “U” becomes the largest. The frame format detection unit 12 outputs the index value of the TDD frame with the largest correlation coefficient value and the first subframe number when the largest correlation coefficient value is obtained to the unused period calculation unit 14.

  The unused period calculation unit 14 refers to the storage unit 13 to read out the information of the TDD frame format corresponding to the index value output by the frame format detection unit 12, and the sub-frame number of the subframe number output by the frame format detection unit 12 Sorts so that the frame is at the top. The unused period calculation unit 14 calculates the position of “D”, that is, the time corresponding to the downlink signal, with the head being 0 seconds, and the calculated time is the downlink TDD transmission period, ie, the uplink TDD untransmitted period I assume. The unused period calculation unit 14 outputs the calculated uplink TDD non-transmission period as the uplink signal band unused period to the registration period calculation unit 15 (step S110).

  For example, it is assumed that the frame format detection unit 12 outputs “3” as the index value and “3” as the first subframe number. At this time, the unused period calculation unit 14 rearranges the frame of index "3" with subframe number "3" at the top to obtain a pattern of "UUDDDDDDDSU". Since it is 1 ms per subframe, the unused period calculation unit 14 calculates the downlink TDD transmission time between 2 ms and 8 ms based on the position of “D” of the pattern, that is, the uplink TDD non-transmission period. Calculated as

  The registration period calculation unit 15 is based on the information on the band unused period of the uplink signal output from the unused period calculation unit 14, the information on the reference time output from the data set generation unit 11, and a predetermined cycle. Calculate the duration of the activation window. The registration period calculation unit 15 outputs the information of the calculated period of the activation window to the band allocation processing unit 30 (step S111).

  In the configuration of the first embodiment, the PON system including the OLT 100 and the ONUs 110-1 to 110-N and in which the upstream optical signal and the downstream optical signal are multiplexed at different wavelengths is the terminal device 400-1- The communication between the BRH 200 and the RRHs 210-1 to 210 -N that communicate with 1 to 400 -N-1 according to the TDD scheme is relayed. In the band unused period detection device 10 provided in the OLT 100, the data set generation unit 11 is linkage information generated based on scheduling information of signals transmitted and received between the BBU 200 and the RRHs 210-1 to 210-N. The PON system acquires cooperation information used when allocating the band of the upstream optical signal, and the information indicating the period allocated for transmission of the upstream signal obtained from the acquired cooperation information is time-series on the time axis. The transmission period patterns of the upstream signals are arranged side by side, the time axis is divided based on the length of the frame used in the time division duplex system, and the divided time axes are superimposed to generate a data set. The frame format detection unit 12 detects information on a TDD frame format corresponding to the data set, based on the data set and information on a plurality of TDD frame formats determined in advance. The unused period calculation unit 14 calculates the band unused period of the upstream signal in the PON system based on the information on the frame format. The registration period calculation unit 15 is an upstream signal based on the reference time obtained from the linkage information initially acquired by the data set generation unit 11 and the information on the band unused period of the upstream signal calculated by the unused period calculation unit. Calculate the period for allocating the band in the unused period of band. Therefore, it is possible to detect the band unused period of the upstream signal at any timing without depending on traffic. As a result, it is possible to provide an activation window period without affecting the upstream signal transmission period of the ONUs 110-1 to 110-N.

  For example, in the techniques disclosed in Patent Document 2 and Non-Patent Document 3, the TDD non-transmission period of uplink is estimated from the traffic volume of uplink and the test pattern of uplink signal using a traffic monitor. On the other hand, in the present embodiment, the data set is generated using the allocation start time of the collaboration information obtained from the scheduling information. Therefore, in the present embodiment, it is possible to obtain information on the generation timing of the upstream signal without depending on the traffic. As described above, since it is possible to more accurately obtain the information on the generation timing of the uplink signal, it is possible to more accurately determine the downlink TDD transmission time and the uplink TDD non-transmission period.

  Since the allocation start time included in the linkage information indicates the time when allocation is started for the uplink signal, the unassigned time is detected based on the allocation start time, and the detected time is downlink TDD transmission A method of determining it as a period is also conceivable. However, in this method, when uplink transmission request is not generated, allocation is not performed even in uplink TDD transmission period, so it is assumed that unallocated time is downlink TDD transmission time. It can not be determined. On the other hand, in the present embodiment, the start time of the uplink signal obtained from a plurality of pieces of cooperation information is acquired, and the most similar format is detected from among the TDD frame formats. Therefore, downlink TDD transmission time can be detected according to the TDD frame format, and uplink TDD non-transmission period can be detected more accurately.

(Exception processing in the first embodiment)
7 and 8 are flowcharts showing exception processing in the first embodiment. Here, exception processing means that the allocation start time of the upstream signal included in the linkage information newly output by the collaboration connection device 180 is between the bandwidth unused periods of the upstream signal detected by the bandwidth unused period detection device 10 It is processing when it is included. As described below, there are exception processing by the band allocation processing unit 30 and exception processing by the registration period calculation unit 15.

(Exception processing by the bandwidth allocation processing unit)
FIG. 7 is a flowchart showing exception processing by the bandwidth allocation processing unit 30. As a premise of the process illustrated in FIG. 7, the bandwidth allocation processing unit 30 is in the middle of processing that performs bandwidth allocation processing of the activation window period based on the activation window period output by the registration period calculation unit 15. State or assigned state. Further, in the block diagram of FIG. 3, there are connection lines for transmitting instruction information between the band allocation processing unit 30 and the upstream frame processing unit 50, and between the band allocation processing unit 30 and the band unused period detection device 10. It shall exist.

  The band allocation processing unit 30 acquires the cooperation information output by the cooperation connection device 180 via the IF 80 (step Sa201). The band allocation processing unit 30 reads out information on the allocation start time of the uplink signal included in the acquired cooperation information. The band allocation processing unit 30 determines whether the read out allocation start time of the uplink signal is included in the period of the activation window received from the registration period calculation unit 15 (step Sa202).

  When it is determined that the allocation start time of the uplink signal that has been read out is not included in the period of the activation window (step Sa202-NO), the band allocation processing unit 30 ends the processing. On the other hand, when the band allocation processing unit 30 determines that the read out allocation start time of the uplink signal is included in the period of the activation window (YES in step Sa202), the activation process is ended and a new process is performed. A band allocation process is performed according to the cooperation information (step Sa203).

  If it is in the middle of the process which is performing the band allocation process of the period of the activation window, the band allocation processing unit 30 ends its own process. At this time, the band allocation processing unit 30 may initialize the band allocation process.

  On the other hand, if the bandwidth of the activation window has already been allocated, it is necessary to cancel the activation window period. For example, the bandwidth allocation processing unit 30 transmits a notification for canceling the period of the activation window in which the bandwidth is allocated to the ONU 110-new that is attempting to request a new connection, and transmits a new connection request frame. Do not let

  The band allocation processing unit 30 outputs instruction information to cause the band unused period detection device 10 to redetect the band unused period of the uplink signal (step Sa204). In response to the instruction information, the band unused period detection device 10 performs the process shown in FIG. 5 and outputs a new activation window period to the band allocation processing unit 30.

(Exception processing by registration period calculation unit)
FIG. 8 is a flowchart showing exception processing by the registration period calculation unit 15. As a premise of the process shown in FIG. 8, the registration period calculation unit 15 performs the process of calculating the activation window period based on the band unused period of the upstream signal output from the unused period calculation unit 14. Suppose that it is in the middle.

  While the registration period calculation unit 15 calculates the period of the activation window based on the band unused period of the uplink signal, the information of the new reference time output by the data set generation unit 11 is acquired (step Sb 301). The registration period calculation unit 15 determines whether the reference time is included in the band unused period of the upstream signal received from the unused period calculation unit 14 (step Sb302).

  A process is complete | finished when the registration period calculation part 15 determines that the said reference | standard time is not contained in the band unused period of the upstream signal (step Sb302-NO). On the other hand, when the registration period calculation unit 15 determines that the reference time is included in the band unused period of the upstream signal (step Sb302-YES), the registration period calculation unit 15 determines the period of the activation window. The calculation of is completed (step Sb303). When the unused period calculating unit 14 outputs the information on the band unused period of the new uplink signal, the registration period calculating unit 15 outputs the information about the activation window based on the band unused period of the new uplink signal. Calculate the period.

  When the band of the upstream signal is allocated by the scheduling by the BBU 200 to the band unused period detected by the band unused period detecting device 10 by the exception processing shown in FIG. 7 and FIG. It is possible to forcibly end the use period. This can prevent the communication in the mobile front hall from being affected.

  In the first embodiment described above, the pattern of the transmission period of the uplink signal is recorded in the data set DS1 based on the allocation start time of the uplink signal included in the cooperation information. It is not limited to the embodiment. For example, a period in which the cooperative connection apparatus 180 outputs the cooperative information to the OLT 100 is a period allocated to the downstream signal. Therefore, the time at which the data set generation unit 11 acquires the linkage information indicates the time assigned to the downlink signal. Therefore, the data set generation unit 11 may generate the data set DS1 by setting the time at which the cooperation information is acquired as the allocation time of the downlink signal instead of the allocation start time of the uplink signal included in the cooperation information.

  When the time at which cooperation information is acquired is used as the allocation time of the downlink signal, the frame format detection unit 12 sets the position of “D” in the TDD frame format to “1”, and the positions of “U” and “S” to “0”. The cross-correlation operation is performed by generating the cross-correlation array as "." Also, in this case, the data set generation unit 11 outputs the acquisition time of the cooperation information acquired first as the reference time to the registration period calculation unit 15a, and the allocation start time of the uplink signal included in the cooperation information acquired first The above information is output to the registration period calculation unit 15. While the registration period calculation unit 15 calculates the period of the activation window based on the reference time, in the case of exception processing, the exception processing of step Sb302 in FIG. 8 is performed using the allocation start time of the uplink signal. Will do.

  Further, information on both the assignment start time of the uplink signal and the assignment time of the downlink signal may be used. By doing this, it is possible to increase information on the pattern of the transmission period of the signal, so that the frame format detection unit 12 performs the cross-correlation calculation based on the patterns of the transmission period of both the upstream signal and the downstream signal. More accurate detection of TDD frame format can be performed.

Second Embodiment
FIG. 9 is a block diagram showing the configuration of the second embodiment. In FIG. 9, the same components as those of the first embodiment are denoted by the same reference numerals, and different components will be described below. The other system host apparatus 200a, which is the host apparatus, provides a new communication service using, for example, the band unused period of the upstream signal calculated by the unused period calculating unit 14.

  The OLT 100a has a band unused period detecting device 10a in place of the band unused period detecting device 10 included in the OLT 100, and has a configuration in which IFs 70i-2 and 71i-2 are added as respective interfaces of L2SWs 70 and 71. Each of the IFs 70i-2 and 71i-2 is connected to the IFs 200ai-d and 200ai-u of the other system higher-level device 200a. The band unused period detection device 10 a includes a registration period calculation portion 15 a in place of the registration period calculation portion 15 included in the band unused period detection device 10.

  In addition to the configuration of the registration period calculation unit 15, the registration period calculation unit 15a calculates and calculates a period during which the uplink band is allocated to the other system host apparatus 200a among the band unused periods of uplink signals. The information indicating the period is output to the band allocation processing unit 30. The band allocation processing unit 30 allocates a band based on a period for allocating an uplink band output by the registration period calculation unit 15a. Thus, the other system higher-level device 200a uses the uplink bandwidth allocated by the bandwidth allocation processing unit 30 to the terminal devices 400-1-1 to 400-N-1 through the RRHs 210-1 to 210-N. Receive a request related to the communication service to be provided.

  The unused period calculation unit 14 may be configured to calculate the band unused period of the downlink signal in addition to the band unused period of the uplink signal. When calculating the band unused period of the downlink signal, the registration period calculation unit 15a calculates a period to be allocated to the other system host apparatus 200a in the downlink signal, and the other system host apparatus 200a uses the period to calculate the terminal device 400. Requests relating to the provided communication service can also be sent to -1-1-1 to 400-N-1.

  Also in the second embodiment described above, as in the first embodiment, the data set generation unit 11 changes the time to start assignment of the upstream signal included in the cooperation information, and then downloads the time when the cooperation information is acquired. The data set DS1 may be generated as a signal allocation time. Also in the second embodiment, information on both the assignment start time of the uplink signal and the assignment time of the downlink signal may be used.

  Also in the second embodiment, the exception processing of FIGS. 7 and 8 shown in the first embodiment may be performed similarly. Further, in the second embodiment, the exception processing shown in FIG. 7 and FIG. 8 may be performed with respect to the case where the unused period calculation unit 14 calculates the band unused period of the downlink signal. When the unused period calculation unit 14 performs the exception processing of FIG. 7 and FIG. 8 when calculating the band unused period of the downlink signal, the time when the band allocation processing unit 30 acquires new cooperation information is the allocation of the downlink signal It will indicate the time. Therefore, in step Sa202 of FIG. 7, the band allocation processing unit 30 determines whether or not the time is included in the downlink allocation period received from the registration period calculation unit 15a. Further, in the process of FIG. 8, since the time when the data set generation unit 11 acquires new cooperation information indicates the assignment time of the downlink signal, the registration period calculation unit 15 a performs the process in step Sb 302 of FIG. It is determined whether or not the acquired time is included in the band unused period of the downlink signal calculated by the unused period calculation unit 14.

  In the first and second embodiments described above, when the frame format detection unit 12 performs the cross-correlation calculation, rearrangement is performed with “U” as the head in each of the seven TDD frame formats. , The pattern according to the number of "U" is generated, but the configuration of the present invention is not limited to the embodiment. For example, in each of the seven TDD frame formats, reordering is performed with "U" at the top to set the position of "U" to "1", and the positions of "D" and "S" to "0". The cross-correlation array may be generated and stored in the storage unit 13.

  For example, for each index, there are six "U" s at index "0", so six patterns will be generated. Since there are four "U" s in the index "1", four patterns will be generated. Since there are two “U” in the indexes “2” and “4”, two patterns are generated. Since there are three "U" in the index "3", three patterns will be generated. Since there is one "U" in the index "5", one pattern is generated. As the index "6" has five "U" s, five patterns will be generated. Then, in total, 6 + 4 + 2 × 2 + 3 + 1 + 5 = 23 patterns exist. Therefore, 23 cross-correlation arrays are generated in advance, index values are newly added to each, and stored in the storage unit 13. By doing this, the frame format detection unit 12 does not need to perform rearrangement, and the format can be specified only by the index value, so that the first subframe number is output to the unused period calculation unit 14 There is no need for it. The unused period calculation unit 14 can detect the corresponding pattern by referring to the storage unit 13 based on the index value output by the frame format detection unit 12.

  Further, the cross correlation calculation performed by the frame format detection unit 12 is not limited to the above-described method. For example, a pattern in which a predetermined number of TDD frame formats are repeated is generated, and a convolution operation is performed on the generated patterns using data set DS3, and the most similar TDD frame format is generated based on the magnitude of the peak value. May be detected.

  Also, in the first and second embodiments described above, the band unused period of the uplink signal is detected based on the linkage information for all the RRHs 210-1 to 210-N. Band unused periods of uplink signals of all other RRHs 210-1 to 210-N may be detected based on linkage information for one RRH 210-i.

  Further, in the first and second embodiments described above, the data set generation unit 11 acquires cooperation information during a time designated in advance, and the more accurate the information transmission, the more the cooperation information to be acquired. A pattern of periods will be obtained. On the other hand, since the storage capacity allocated to the band non-use period detection device 10, 10a is limited, the designation time is limited according to the size of the array number of the data set DS1 which can be secured in the data set generation unit 11. It will be In addition to the time setting, the number of collaboration information and the data amount may be specified, or conditions combining these may be used. The seven TDD frame formats shown in FIG. 4 are not dynamically switched or switched in a short time. For example, the same frame format is used from morning to evening, and evening to morning Switching is performed with a long cycle, such as switching to another frame format. Therefore, with regard to the time designated in advance, the number of linkage information, and the like, any time or number falling within the cycle in which switching is performed can be selected.

  In the first and second embodiments described above, the allocation start time of the upstream signal included in the cooperation information is used as it is, but a value obtained by adding an offset to the time may be used. The offset may be a fixed value or an adaptively changing value. Also, when using the time when the cooperation information is acquired, a value to which the offset is added may be used.

  Further, in the first and second embodiments described above, the cooperative connection device 180 may be provided outside the OLT 100, 100a as shown in FIGS. 3 and 9, or inside the BBU 200. It may be provided inside the OLT 100, 100a. Further, as shown in FIG. 3 and FIG. 9, instead of physically connecting to the OLT 100, 100a via different IFs 80, it is possible to connect to the OLT 100, 100a by an interface divided virtually or logically. Good.

  In the first and second embodiments described above, the band unused period detection device 10, 10a is provided inside the OLT 100, 100a, but may be provided outside the OLT 100, 100a. , And may be provided inside the cooperative connection device 180 or the BBU 200.

  In the first and second embodiments described above, the PON system relays the information transmitted / received by the BBU 200 and the RRHs 210-1 to 210-N, but the present invention is limited to the embodiments. Absent. The present invention is not limited to the network topology, and an optical transmission system having a network topology such as a ring configuration or a bus configuration may be applied instead of the PON system.

  In the first and second embodiments described above, the scheduling information output by the BBU 200 is information obtained by scheduling uplink signals from the RRHs 210-1 to 210-N to the BBU 200. The configuration is not limited to the embodiment. It may be scheduling information obtained by scheduling uplink and downlink signals transmitted and received between the RRHs 210-1 to 210-N and the BBU 200. In this case, the cooperative connection apparatus 180 uplinks from the scheduling information. The cooperation information including the allocation start time of the signal and the allocation data amount will be generated.

  In the first and second embodiments described above, wireless communication is performed between the RRHs 210-1 to 210-N and the terminal devices 400-1-1 to 400-N-1, but a time division duplex system is used. Any communication method may be used, and a wired communication method may be used.

  The band unused period detection device 10 or 10a and the OLT 100 or 100a in the above-described embodiment may be realized by a computer. In that case, a program for realizing this function may be recorded in a computer readable recording medium, and the program recorded in the recording medium may be read and executed by a computer system. Here, the “computer system” includes an OS and hardware such as peripheral devices. The term "computer-readable recording medium" refers to a storage medium such as a flexible disk, a magneto-optical disk, a ROM, a portable medium such as a ROM or a CD-ROM, or a hard disk built in a computer system. Furthermore, “computer-readable recording medium” dynamically holds a program for a short time, like a communication line in the case of transmitting a program via a network such as the Internet or a communication line such as a telephone line. It may also include one that holds a program for a certain period of time, such as volatile memory in a computer system that becomes a server or a client in that case. Further, the program may be for realizing a part of the functions described above, or may be realized in combination with the program already recorded in the computer system. It may be realized using a programmable logic device such as an FPGA (Field Programmable Gate Array).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Band unused period detection apparatus, 11 ... Data set production | generation part, 12 ... Frame format detection part, 13 ... Storage part, 14 ... Unused period calculation part, 15 ... Registration period calculation part

Claims (8)

A subscriber line termination unit to which a terminal unit and a communication unit performing communication by time division duplex system are connected, and a subscriber line termination unit connected to the subscriber line termination unit via an optical fiber A band unused period used in a communication system in which an optical transmission system in which a signal and a downstream optical signal are multiplexed at different wavelengths is used to relay communication between an upper apparatus connected to the subscriber line terminal apparatus and the communication apparatus A detection device,
It is cooperation information generated based on scheduling information of signals transmitted and received between the host apparatus and the communication apparatus, and the cooperation information used when the optical transmission system allocates a band is acquired and acquired The information indicating the period allocated to the transmission of the signal obtained from the cooperation information is arranged in time series on the time axis to make the transmission period pattern of the signal, and the time axis is a frame used in the time division duplex system A data set generation unit that generates a data set by dividing based on the length and overlapping the divided time axes;
A frame format detection unit that detects information related to the frame format corresponding to the data set based on the data set and information on a plurality of frame formats of the time division duplex system determined in advance;
An unused period calculation unit that calculates a band unused period in the optical transmission system based on the information on the frame format detected by the frame format detection unit;
A band is allocated in the band unused period based on the reference time obtained from the linkage information first acquired by the data set generation unit and the information on the band unused period calculated by the unused period calculating unit A registration period calculation unit which calculates a period and outputs the calculated period to the subscriber line terminal device;
A band unused period detection device comprising: The registration period calculation unit
When the unused period calculation unit calculates the band unused period of the uplink signal, the period allocated to the transmission of the uplink signal obtained from the new cooperation information acquired by the data set generation unit is the uplink When it is included in the band unused period of the signal, the calculation of the period to allocate the band in the band unused period of the uplink signal is ended, and the unused period calculation unit calculates the band unused period of the downlink signal; When a period allocated to transmission of the downlink signal obtained from the new cooperation information acquired by the data set generation unit is included in the band unused period of the downlink signal, in the band unused period of the downlink signal The band unused period detection device according to claim 1, wherein the calculation of the band allocation period is ended. The frame format detection unit
Calculation method for performing cross correlation calculation based on transmission pattern of uplink signal included in the data set and pattern of a period allocated to the uplink signal of the frame format, transmission of downlink signal included in the data set A calculation method for performing cross correlation calculation based on a pattern and a pattern of a period allocated to the downlink signal of the frame format, transmission patterns of uplink signals and downlink signals included in the data set, and the frame format Information on the frame format corresponding to the data set is detected by performing any of the calculation methods of performing the cross correlation calculation based on the pattern of the period assigned to the upstream signal and the downstream signal. The band unused period detection apparatus according to claim 1. The data set generation unit
The allocation start time of the uplink signal included in the cooperation information is acquired as information indicating a period allocated to transmission of the signal, and the acquired allocation start time of the uplink signal is arranged in time series on the time axis. Alternatively, as information indicating a period allocated to transmission of the signal, the time at which the cooperation information is acquired is acquired as the time allocated to the downlink signal, and is allocated to the acquired downlink signal The time is arranged in time series on the time axis, or the allocation start time of the uplink signal and the time allocated to the downlink signal are arranged in time series on the time axis. The band unused period detection device according to Item. The optical transmission system is a PON system,
The unused period calculation unit
The band unused period of the upstream signal in the PON system is calculated based on the frame format detected by the frame format detection unit,
The registration period calculation unit
Uplink calculated by the reference time and the unused period calculation unit, a new connection request acceptance period for receiving and registering a new connection request transmitted by the subscriber line termination device newly connected to the PON system 5. The band unreported according to any one of claims 1 to 4, wherein the information of the new connection request acceptance period calculated based on the band unused period of the signal is output to the subscriber line terminal station apparatus. Usage period detection device. A subscriber line termination unit to which a terminal unit and a communication unit performing communication by time division duplex system are connected, and a subscriber line termination unit connected to the subscriber line termination unit via an optical fiber A subscriber line end used in a communication system in which an optical transmission system in which a signal and a downstream optical signal are multiplexed at different wavelengths is used to relay communication between an upper apparatus connected to the subscriber line terminal apparatus and the communication apparatus A station apparatus,
It is cooperation information generated based on scheduling information of signals transmitted and received between the host apparatus and the communication apparatus, and the cooperation information used when the optical transmission system allocates a band is acquired and acquired The information indicating the period allocated to the transmission of the signal obtained from the cooperation information is arranged in time series on the time axis to make the transmission period pattern of the signal, and the time axis is a frame used in the time division duplex system A data set generation unit that generates a data set by dividing based on the length and overlapping the divided time axes;
A frame format detection unit that detects information related to the frame format corresponding to the data set based on the data set and information on a plurality of frame formats of the time division duplex system determined in advance;
An unused period calculation unit that calculates a band unused period in the optical transmission system based on the information on the frame format detected by the frame format detection unit;
A band is allocated in the band unused period based on the reference time obtained from the linkage information first acquired by the data set generation unit and the information on the band unused period calculated by the unused period calculating unit A registration period calculation unit that calculates a period;
A band allocation processor for allocating a band based on a period for allocating the band calculated by the registration period calculator;
Subscriber line terminal equipment comprising:   When the band allocation processing section allocates the band of the uplink signal, a period allocated to transmission of the uplink signal obtained from the newly acquired cooperation information allocates the band in the uplink direction When it is included in the period, or when the bandwidth of the downlink signal is allocated, the period allocated for transmission of the downlink signal obtained from the newly acquired cooperation information is the downlink direction. The subscriber line termination device according to claim 6, wherein allocation of the band is ended when included in a period of allocating a band. A subscriber line termination unit to which a terminal unit and a communication unit performing communication by time division duplex system are connected, and a subscriber line termination unit connected to the subscriber line termination unit via an optical fiber A band unused period performed in a communication system in which an optical transmission system in which a signal and a downstream optical signal are multiplexed at different wavelengths relays communication between a host apparatus connected to the subscriber line terminal apparatus and the communication apparatus A detection method,
Cooperative information generated based on scheduling information of a signal transmitted / received between the host apparatus and the communication apparatus, which is used when the optical transmission system allocates a band,
The information indicating the period assigned to the transmission of the signal obtained from the acquired cooperation information is arranged in time series on the time axis to make the transmission period pattern of the signal,
Dividing the time axis based on a length of a frame used in the time division duplex system;
Create a data set by overlaying the divided time axes,
Information on the frame format corresponding to the data set is detected based on the generated data set and information on a plurality of frame formats of the time division duplex scheme determined in advance;
A band unused period in the optical transmission system is calculated based on the detected information on the frame format,
A band unused period detection method for calculating a period for allocating a band in the band unused period based on a reference time obtained from the cooperation information acquired first and information on the calculated band unused period.

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