Patent Application
20210028857
The present disclosure relates to an optical transmission system and a communication condition selection method.
An example of a configuration of an optical transmission system which performs 1-to-N transmission and reception of optical signals includes an optical transmission system 900 as illustrated in
Non-Patent Literature 1: J. R. Stern, et. al., “PASSIVE OPTICAL LOCAL NETWORKS FOR TELEPHONY APPLICATIONS AND BEYOND”, ELECTRONICS LETTERS, vol. 23, no. 24 pp. 1255 to 1256, November 1987
Meanwhile, in the configuration in which passive optical elements such as the light splitter 950 are used, a part of the transmission line is shared by a plurality of optical signals having different grounds. For example, in the configuration of the optical transmission system 900 described above, an optical fiber 990 between the optical transmission and reception apparatus 910 and the light splitter 950 is connected to the light splitter 950 and an optical transponder provided in the optical transmission and reception apparatus 910. Thus, the optical fiber 990 is shared during transmission and reception of optical signals between the optical transmission and reception apparatus 910 and each of the optical transmission and reception apparatuses 920-1 to 920-N.
In this case, the optical transmission and reception apparatus 910 needs to transmit and receive optical signals in accordance with a receivable communication quality at a point where transmission line conditions are the most strict. For example, in
In this case, the optical transmission and reception apparatus 910 transmits and receives the optical signals at the limited communication condition to and from the optical transmission and reception apparatuses 920-2 to 920-N other than the optical transmission and reception apparatus 920-1. Thus, there is a problem in that the overall communication quality of the optical transmission system 900 is limited to the communication quality in the ground having the strictest transmission line condition.
In view of the above problem, an object of the present disclosure is to provide a technology capable of selecting an appropriate communication condition for each around in accordance with a transmission line condition for each ground, in an optical transmission system which performs 1-to-N transmission and reception of optical signals s an integer equal to or greater than 1).
According to one aspect of the present disclosure, there is provided an optical transmission system in which a plurality of optical transmission and reception apparatuses perform 1-to-N transmission and reception of optical signals (N is an integer equal to or greater than 1), the optical transmission system being configured to select a communication condition that includes at least a modulation scheme or a baud rate and is a communication condition when each of the optical transmission and reception apparatuses performs transmission and reception in accordance with a transmission line condition, the transmission line condition being between any one first optical transmission and reception apparatus and each of second optical transmission and reception apparatuses, which are N grounds, other than the first optical transmission and reception apparatus.
The optical transmission system according to one aspect of the present disclosure, including: an optical passive element configured to branch an optical signal transmitted by the first optical transmission and reception apparatus and transmit the optical signals to each of the second optical transmission and reception apparatuses in a case where the first optical transmission and reception apparatus is on a transmission side, and configured to combine optical signals transmitted by the second optical transmission and reception apparatuses and transmit the optical signal to the first optical transmission and reception apparatus in a case where the first optical transmission and reception apparatus is on a reception side.
In the optical transmission system according to one aspect of the present disclosure, the first optical transmission and reception apparatus includes a transmission line condition detection unit configured to detect the transmission line condition that is with each of the second optical transmission and reception apparatuses, a communication condition selection unit configured to select any one of communication conditions associated with each of the transmission line conditions in advance based on the transmission line condition detected by the transmission line condition detection unit, and a communication condition setting unit configured to set the communication condition of an own apparatus and the communication condition, which is to be detected by the transmission line condition detection unit, of the second optical transmission and reception apparatus to the communication condition to be selected by the communication condition selection unit.
In the optical transmission system according to one aspect of the present disclosure, the first optical transmission and reception apparatus includes a reference signal generation unit configured to generate a plurality of reference signals corresponding to each of candidates of the communication condition by performing modulation based on each of the candidates of the communication condition enabling an own apparatus to perform transmission and reception, a reference signal transmission unit configured to transmit the plurality of reference signals generated by the reference signal generation unit and information of the communication conditions corresponding to the plurality of reference signals to each of the second optical transmission and reception apparatuses, and a communication condition selection unit configured to select, based on information related to the reference signal successfully demodulated by each of the second optical transmission and reception apparatuses, the communication condition when transmission and reception with each of the second optical transmission and reception apparatuses is performed, the second optical transmission and reception apparatus includes a reference signal detection unit configured to receive the plurality of reference signals and the information of the communication conditions corresponding to the plurality of reference signals transmitted by the first optical transmission and reception apparatus, demodulate, based on the communication conditions corresponding to the plurality of reference signals, the plurality of reference signals received, and detect the reference signal successfully demodulated, and a registration processing unit configured to transmit a registration request signal including information related to the reference signal detected by the reference signal detection unit to the first optical transmission and reception apparatus, and the first optical transmission and reception apparatus and the second optical transmission and reception apparatus transmit and receive the optical signal in accordance with the communication condition selected by the communication condition selection unit.
In the optical transmission system according to one aspect of the present disclosure, in a case where the communication condition includes the modulation scheme and the baud rate, when transmitting each of the plurality of reference signals, the reference signal transmission unit transmits the plurality of reference signals by rearranging the plurality of reference signals so that the reference signals having the same modulation scheme are continuous, the reference signals having the same baud rate are continuous, or the reference signals having a same length of the reference signal are continuous, or by adding a payload signal having a length in accordance with a length of each of the plurality of reference signals generated by the reference signal generation unit.
In the optical transmission system according to one aspect of the present disclosure, when generating the plurality of reference signals, the reference signal generation unit generates the reference signals so that each of the reference signals has the same length.
In the optical transmission system according to tone aspect of the present disclosure, a guard time signal having a signal length in accordance with a length of a time required to change the communication condition is inserted before and after each of the plurality of reference signals.
According to one aspect of the present disclosure, there is provided a communication condition selection method when a plurality of optical transmission and reception apparatuses perform 1-to-N transmission and reception of optical signals (N is an integer equal to or greater than 1), the communication condition selection method comprising: selecting a communication condition that includes at least a modulation scheme or a baud rate and is a communication condition when each of the optical transmission and reception apparatuses performs transmission and reception in accordance with a transmission line condition, the transmission line condition being between any one first optical transmission and reception apparatus and each of second optical transmission and reception apparatuses, which are N grounds, other than the first optical transmission and reception apparatus.
According to the present disclosure, in an optical transmission system which performs 1-to-N transmission and reception of optical signals, an appropriate communication condition can be selected for each ground in accordance with a transmission line condition for each ground.
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
The optical multiplexer-demultiplexer 40 is, for example, an optical passive element such as a light splitter, an optical coupler, or an optical multiplexer, and branches an optical signal transmitted by the optical transmission and reception apparatus 10, and transmits the optical signal to the optical transmission and reception apparatuses 20-1 to 20-4. The optical multiplexer-demultiplexer 40 combines optical signals transmitted by the optical transmission and reception apparatuses 20-1 to 20-4, and transmits the optical signal to the optical transmission and reception apparatus 10. That is, the optical transmission system 1 performs 1-to-4 transmission and reception of optical signals with the optical transmission and reception apparatuses 20-1 to 20-4 as four grounds.
The OpS apparatus 50 is an operation system, for example, in response to an operation by an operator of the optical transmission system 1, sets a communication condition according to a transmission line condition for the optical transmission and reception apparatus 10, The OpS apparatus 50 receives the operation by the operator of the optical transmission system 1 to set communication conditions in accordance with transmission line conditions to the optical transmission and reception apparatuses 20-1 to 20-4 via the optical transmission and reception apparatus 10. For example, the communication condition is set for a Digital Signal Processor (DSP), which performs a modulation process or a demodulation process, provided in the optical transmission and reception apparatuses 10 and 20-1 to 20-4.
Here, the transmission line condition is, for example, a length of a transmission distance between the optical transmission and reception apparatus 10 and each of the optical transmission and reception apparatuses 20-1 to 20-4, a transmission and reception power or an Optical Signal to Noise Ratio (OSNR) which increases or decreases in accordance with the length of the transmission distance, or the like.
The communication condition is a condition such as a modulation scheme, a baud rate, or the like which changes a communication quality, such as a communication capacity. As the modulation scheme, polarization multiplexing Quadrature Phase Shift Keying (QSPK) or quadrature amplitude modulation realized by using a digital coherent optical signal is applied. In the following, in one example, a description is given assuming that any one of 8 QAM, 16 QAM, and 64 QAM having different multi-levels in Quadrature Amplitude Modulation (QAM) is applied.
In the optical transmission system 1, regarding transmission distances between the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-1 to 20-4, it is assumed that a transmission distance to each of the optical transmission and reception apparatuses 20-2 and 20-3 is longer than a transmission distance to each of the optical transmission and reception apparatuses 20-1 and 20-4. In this case, an ONSR in each of the optical transmission and reception apparatuses 20-1 and 20-4 is higher than an OSNR of each of the optical transmission and reception apparatuses 20-2 and 20-3.
Thus, even when a communication condition of a modulation scheme having a large multi-level such as 64 QAM, for example, is applied to the optical transmission and reception apparatuses 20-1 and 20-4 having the high OSNRs, it is expected that optical signals can be transmitted and received without bit errors or the like. In contrast, in a case where the communication condition of the modulation scheme having a large multi-level such as 64 QAM is applied to the optical transmission and reception apparatuses 20-2 and 20-3 having the low OSNRs, it is expected that bit errors or the like may occur and the optical signals cannot be stably transmitted and received.
Thus, an operator of the optical transmission system 1 operates the OpS apparatus 50 to set information setting, for example. 64 QAM having high multi-levels as a modulation scheme to be applied to transmission and reception of optical signals to the optical transmission and reception apparatus 20-1 and the optical transmission and reception apparatus 20-4. In addition, the operator of the optical transmission system 1 operates the OpS apparatus 50 to set information setting 64 QAM as the modulation scheme to be applied to transmission and reception of optical signals between the optical transmission and reception apparatuses 20-1 and 20-4 to the optical transmission and reception apparatus 10,
In contrast, with respect to the optical transmission and reception apparatus 20-2 and the optical transmission and reception apparatus 20-3, the operator of the optical transmission system 1 operates the OpS apparatus 50 to set information setting, for example, 8 QAM having low multi-levels as the modulation scheme to be applied to transmission and reception of optical signals. In addition, the operator of the optical transmission system 1 operates the OpS apparatus 50 to set information setting 8 QAM as the modulation scheme to be applied to transmission and reception of optical signals between the optical transmission and reception apparatuses 20-2 and 20-3 to the optical transmission and reception apparatus 10.
With this setting as described above, in the optical transmission system 1, by applying 64 QAM having high multi-levels, the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-1 and 20-4 can efficiently transmit and receive optical signals with a large communication capacity. In contrast, 8 QAM having low multi-levels is applied to the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-2 and 20-3, so that efficiency of communication is less than 64 QAM, but transmission and reception of optical signals can be stably performed.
In the method of using the OpS apparatus 50 described above, the operator of the optical transmission system 1 operates the OpS apparatus 50 after checking the transmission line condition, and manually sets the modulation scheme to the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-1 to 20-4. In contrast, by configuring the optical transmission and reception apparatus 10 as illustrated in
As illustrated in
For example,
For example, in
In addition, the communication condition setting unit 13 of the optical transmission and reception apparatus 10 sets information setting 8 QAM having low multi-levels as a modulation scheme to be applied to transmission and reception of optical signals to the optical transmission and reception apparatus 20-2 and the optical transmission and reception apparatus 20-3. Further, the communication condition setting unit 13 of the optical transmission and reception apparatus 10 sets information setting 8 QAM as the modulation scheme to be applied to transmission and reception of optical signals between the optical transmission and reception apparatuses 20-2 and 20-3 for its own apparatus.
Thus, in the optical transmission system 1, by applying 64 QAM having high multi-levels, the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-1 and 20-4 can efficiently transmit and receive optical signals with a large communication capacity. In contrast, 8 QAM having low multi-levels is applied to the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-2 and 20-3, so that efficiency of communication is less than 64 QAM, but transmission and reception of optical signals can be stably performed.
With the configuration of the first embodiment described above, the optical transmission system 1 performs 1-to-4 transmission and reception of optical signals, but the number of grounds is not limited to four, and N optical transmission and reception apparatuses 20-1 to 20-N may be connected to the optical multiplexer-demultiplexer 40 to perform 1-to-N transmission and reception of optical signals. Meanwhile, the minimum configuration may be 1-to-1, so N is an integer equal to or greater
Further, in the configuration of the first embodiment described above, the appropriate modulation scheme may be selected in accordance with the transmission distance, but as described above, a communication condition other than the modulation scheme, for example, a baud rate may be selected. That is, as a combination of communication conditions, there is a combination in which the baud rate is a fixed value and the modulation scheme is variable, a combination in which the modulation scheme is fixed and the baud rate is a variable value, or a combination in which both of the modulation scheme and the baud rate are variable. As described above, a transmission and reception power, an OSNR, or the like may be applied instead of the transmission distance as the transmission line condition.
According to the configuration of the first embodiment described above, the optical transmission system 1 includes at least three or more optical transmission and reception apparatuses 10 and 20-1 to 20-N and the optical multiplexer-demultiplexer 40, which is an optical passive element connected to the optical transmission and reception apparatuses 10 and 20-1 to 20-N, and performs 1-to-N transmission and reception of optical signals. In the optical transmission system 1, the transmission line condition detection unit 11 of the optical transmission and reception apparatus 10 detects a transmission line condition between the optical transmission and reception apparatus 10 and each of the optical transmission and reception apparatuses 20-1 to 20-N. The communication condition selection unit 12 selects any one of communication conditions associated with each of the transmission line conditions in advance based on the transmission line condition detected by the transmission line condition detection unit 11, The communication condition setting unit 13 sets the communication condition of its own apparatus and the communication conditions of the optical transmission and reception apparatuses 20-1 to 20-N to be detected by the transmission line condition detection unit 11 to communication conditions selected by the communication condition selection unit 12. As a result, in the optical transmission system 1, an appropriate communication condition can be selected for each of the optical transmission and reception apparatuses 20-1 to 20-N in accordance with the transmission line conditions for each of the optical transmission and reception apparatuses 20-1 to 20-N which are grounds.
In the configuration of the first embodiment described above, the optical transmission and reception apparatus 10 includes the transmission line condition detection unit 11, the communication condition selection unit 12, the communication condition setting unit 13, and the storage unit 14, but the configuration of the present disclosure is not limited to the embodiment described above. For example, the OpS apparatus 50 connected to the optical transmission and reception apparatus 10 may include the transmission line condition detection unit 11, the communication condition selection unit 12. the communication condition setting unit 13. and the storage unit 14. In this case, the communication condition setting unit 13 sets the communication condition selected by the communication condition selection unit 12 to the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-1 to 20-4 to be detected by the transmission line condition detection unit 11.
Instead of connecting all of the optical transmission and reception apparatuses 20-1 to 20-N to the optical multiplexer-demultiplexer 40, optical multiplexer-demultiplexers 41 and 42 may be multi-stage-inserted in the middle of the optical transmission line, for example, as illustrated in
In the first embodiment described above, the PON type optical transmission system 1 is illustrated in one example, but the configuration of the present disclosure is not limited to the embodiment described above. For example, the present disclosure may be applied to the planar communication network, and may be specifically applied to a ring type optical transmission system 1a as illustrated in
Each of the optical passive elements 45-1 to 45-10 included in each of the optical node apparatuses 50-1 to 50-10 separates and combines an optical signal or selectively separates and combines an optical signal having a predetermined wavelength. For example, when viewed from the optical transmission and reception apparatus 10, the optical transmission and reception apparatuses 20-1 to 20-5 are five grounds, and at least one same wavelength is allocated to each of combinations of the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-1 to 20-5 and 1-to-5 transmission and reception of optical signals is performed. In addition, a Wavelength Division Multiplexing (WDM) configuration may be used in which a plurality of wavelengths are allocated to the 1-to-5 communication of optical signals. Further, a WDM configuration may be used in which another wavelength is allocated to each of combinations of the optical transmission and reception apparatus 20-1 and the optical transmission and reception apparatuses 20-2 to 20-5 and 1-to-4 transmission and reception of optical signals is performed.
In the optical transmission system 1a illustrated in
In addition, the communication condition setting unit 13 of the optical transmission and reception apparatus 10 sets information setting 16 QAM having low multi-levels as a modulation scheme to be applied to transmission and reception of optical signals to the optical transmission and reception apparatuses 20-3, 20-4, and 20-5. Further, the communication condition setting unit 13 of the optical transmission and reception apparatus 10 sets information setting 16 QAM as the modulation scheme to be applied to transmission and reception of optical signals between the optical transmission and reception apparatuses 20-3, 20-4, and 20-5 for its own apparatus.
With this setting as described above, in the optical transmission system 1a, by applying 64 QAM having high multi-levels, the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-1 and 20-2 can efficiently transmit and receive optical signals with a large communication capacity. In contrast, 16 QAM having low multi-levels is applied to the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-3, 20-4, and 20-5, so that efficiency of communication is less than those of the optical transmission and reception apparatuses 20-1 and 20-2, but transmission and reception of optical signals can be stably performed. Accordingly, in the optical transmission system 1a, an appropriate communication condition can be selected for each of the optical transmission and reception apparatuses 20-1 to 20-5 in accordance with the transmission line conditions between the optical transmission and reception apparatus 10 and the optical transmission and reception apparatuses 20-1 to 20-5.
The optical multiplexer-demultiplexer 40 branches an optical signal transmitted by the optical transmission and reception apparatus 10 and transmits the optical signal to the optical transmission and reception apparatuses 20b-1 to 20b-N. The optical multiplexer-demultiplexer 40 combines optical signals transmitted by the optical transmission and reception apparatuses 20b-1 to 20b-N, and transmits the optical signal to the optical transmission and reception apparatus 10b. That is, the optical transmission system 2 performs 1-to-N transmission and reception of optical signals with the optical transmission and reception apparatuses 20b-1 to 20b-N as N grounds.
The optical transmission and reception apparatus 10b is, for example, an apparatus corresponding to an Optical Line Terminal (OLT) in a PON scheme, and the optical transmission and reception apparatuses 20b-1 to 20b-N are, for example, apparatuses corresponding to Optical Network Units (ONUS). For example, a Time Division Multiplexing (TDM) scheme is applied to transmission of optical signals from the optical transmission and reception apparatus 10b to the optical transmission and reception apparatuses 20b-1 to 20b-N in a downlink direction. In contrast, for example, a Time Division Multiple Access (TDMA) scheme is applied to transmission of optical signals from the optical transmission and reception apparatuses 20b-1 to 20b-N to the optical transmission and reception apparatus 10b in an uplink direction. Further, different wavelengths are allocated to the optical signal in the uplink direction and the optical signal in the downlink direction, and transmission is performed by a wavelength multiplexing method.
The optical transmission and reception unit 101 is connected to the optical multiplexer-demultiplexer 40 via an optical fiber, and transmits and receives optical signals to and from the optical transmission and reception apparatuses 20b-1 to 20b-N. The reference signal generation unit 102 generates a plurality of reference signals by modulating reference information corresponding for each of combinations of modulation schemes and baud rates with reference to a reference information table 1061 stored by the storage unit 106 in advance.
The reference signal transmission unit 103 is a signal including the plurality of reference signals generated by the reference signal generation unit 102, and transmits a first transmission timing notification signal in the format illustrated in
As illustrated in
The control signal 500 corresponds to header information of the first transmission timing notification signal, and is modulated in a common communication condition. Here, the common communication condition is a communication condition capable of correctly performing demodulation regardless of a transmission distance or the like even in any one of the optical transmission and reception apparatuses 10b and 20b-1 to 20b-N, and is assumed to be 8 QAM and 32 Gbaud, for example.
A signal information 501 included in the control signal 500 is table type information as illustrated in
The guard time signals 600-1, 600-2, 600-3, 600-4, are signals inserted between the control signal 500 and the reference signals 510-1, 510-2, 510-3, . . . .
Based on information of the reference signal which can be correctly received by each of the optical transmission and reception apparatuses 20b-1 to 20b-N, the communication condition selection unit 104 selects a communication condition used for transmission and reception of optical signals with each of the optical transmission and reception apparatuses 20b-1 to 20b-N. The communication condition selection unit 104 outputs information of the selected communication condition to the data transmission and reception unit 107. In addition, the communication condition selection unit 104 writes the information of the selected communication condition for each of the optical transmission and reception apparatuses 20b-1 to 20b-N in a registration information table 1062 stored in the storage unit 106 in association with each of the optical transmission and reception apparatuses 20b-1 to 20b-N to register the optical transmission and reception apparatuses 20b-1 to 20b-N.
When registered, the communication condition selection unit 104 obtains a new registration ID, modulates a registration notification signal including the obtained registration ID and the information of the selected communication condition in the common communication condition, and transmits the registration notification signal to the registered optical transmission and reception apparatuses 20b-1 to 20b-N. This registration ID is, for example, an ID corresponding to a Logical Link ID (UM) in the PON scheme.
With reference to the registration information table 1062 stored in the storage unit 106, the transmission condition transmission unit 105 generates a second transmission timing notification signal including information of the transmission condition to be allocated when transmitting transmission information, for each registered optical transmission and reception apparatuses 20b-1 to 20b-N. Here, the transmission condition is, for example, a communication bandwidth, a transmission timing, or the like when the registered optical transmission and reception apparatuses 20b-1 to 20b-N perform transmission. The transmission condition transmission unit 105 modulates the generated second transmission timing notification signal with the common communication condition, and transmits the second transmission timing notification signal to the optical transmission and reception apparatuses 20b-1 to 20b-N corresponding to the second transmission timing notification signal. The second transmission timing notification signal transmitted by the transmission condition transmission unit 105 is, for example, a signal corresponding to the GATE frame to be transmitted to the registered ONE by the OLT in the PON scheme.
The storage unit 106 stores the reference information table 1061 illustrated in
The registration information table 1062 includes items of “apparatus identification information”, “registration ID”, “modulation scheme”, “baud rate”, “slot length”, and “transmission timing”. For example, identification information (hereinafter, referred to as an apparatus Identification (ID)) such as an address given in advance to each of the optical transmission and reception apparatuses 20b-1 to 20b-N is written to the item of “apparatus identification information”. information of the registration ID obtained by the communication condition selection unit 104 is written to the item of “registration ID”. Information of the modulation scheme and a value of the baud rate are written to the items of “modulation scheme” and “baud rate”. In the items of “slot length” and “transmission timing”, information of the transmission condition, that is, information of a length of a slot used when the optical transmission and reception apparatus 20b transmits transmission data, and information of a time indicating a timing of a start of the transmission. The information of the items of “slot length” and “transmission timing” is rewritten by the transmission condition transmission unit 105 each time the transmission condition transmission unit 105 allocates a new transmission condition to each of the optical transmission and reception apparatuses 20b-1 to 20b-N.
The data transmission and reception unit 107 demodulates reception data received from each of the optical transmission and reception apparatuses 20b-1 to 20b-N in accordance with the communication condition selected by the communication condition selection unit 104 for each of the optical transmission and reception apparatuses 20b-1 to 20b-N. The data transmission and reception unit 107 modulates transmission data transmitted to each of the optical transmission and reception apparatuses 20b-1 to 20b-N ire accordance with the communication condition selected by the communication condition selection unit 104 for each of the optical transmission and reception apparatuses 20b-1 to 20b-N, and transmits the modulated transmission data to the optical transmission and reception apparatuses 20b-1 to 20b-N.
For example, a DSP which is a hardware which performs a modulation process or a demodulation process provided by the optical transmission and reception apparatus 10b is connected to the optical transmission and reception unit 101, and is configured to be shared by the reference signal transmission unit 103, the communication condition selection unit 104, the transmission condition transmission unit 105, and the data transmission and reception unit 107 which perform a. modulation process or a. demodulation process in the common communication condition. The common communication condition is typically set to the DSP, and in a case where the data transmission unit 107 performs transmission and reception based on the communication condition selected by the communication condition selection unit 104, the data transmission unit 107 sets the communication condition to the DSP.
As illustrated in
The reference signal detection unit 202 receives the first transmission timing notification signal transmitted by the optical transmission and reception apparatus 10b. The reference signal detection unit 202 references the signal information 501 of the control signal 500 included in the received first transmission timing notification signal, and demodulates the reference signals 510-1, 510-2, 510-3, . . . included in the first transmission timing notification signal. The reference signal detection unit 202 detects the reference signals 510-1, 510-2, 510-3, . . . successfully demodulated, and outputs information related to the detected reference signals 510-1, 510-2, 510-3, . . . .
The registration processing unit 203 generates a registration request signal including the information related to the reference signals 510-1, 510-2, 510-3, . . . output by the reference signal detection unit 202 and an apparatus ID allocated to an own apparatus. The registration processing unit 203 modulates the generated registration request signal in a common communication condition and transmits the registration request signal to the optical transmission and reception apparatus 10b. The registration processing unit 203 receives the registration notification signal transmitted by the optical transmission and reception apparatus 10b, and writes and stores the registration ID and the information indicating the communication condition included in the received registration notification signal in the storage unit 205.
The communication condition obtainment unit 204 receives the second transmission timing notification signal transmitted by the optical transmission and reception apparatus 10b, and reads the information of the transmission condition from the received second transmission timing notification signal. The communication condition obtainment unit 204 outputs the read information of the transmission condition to the data transmission and reception unit 206, modulates the received response signal in the common communication condition, and transmits the information to the optical transmission and reception apparatus 10b. The storage unit 205 stores the apparatus ID allocated to the own apparatus in advance, and stores the registration ID and the information of the communication condition written by the registration processing unit 203.
The data transmission and reception unit 206 reads reception data corresponding to the registration ID allocated to the own apparatus from the reception data received from the optical transmission and reception apparatus 10b, and demodulates the read reception data in accordance with the communication condition stored in the storage unit 205. The data transmission and reception unit 206 modulates transmission data to be transmitted to the optical transmission and reception apparatus 10b in accordance with the communication condition stored in the storage unit 205, and transmits the modulated transmission data in accordance with the transmission condition obtained by the communication condition obtainment unit 204.
For example, a DSP, which is a hardware which performs a modulation process or a demodulation process, included in the optical transmission and reception apparatus 20b is connected to the optical transmission and reception unit 201, and is configured to be shared by the reference signal detection unit 202, the registration processing unit 203, the communication condition obtainment unit 204, and the data transmission and reception unit 206 which perform a modulation process or a demodulation process in the common communication condition. The common communication condition is typically set to the DSP, and in a case where the reference signal detection unit 202 performs the demodulation process based on the communication condition of the signal information 501 of the first transmission timing notification signal, the reference signal detection unit 202 sets the communication condition to the DSP. The data transmission unit 206 sets the communication condition to the DSP even in a case where the data transmission unit 206 performs transmission and reception based on the communication condition selected by the communication condition obtainment unit 204.
The reference signal transmission unit 103 outputs instruction information to generate the reference signals 510-1, 510-2, 510-3, . . . to the reference signal generation unit 102. When receiving the instruction information from the reference signal transmission unit 103, the reference signal generation unit 102 references the reference information table 1061 of the storage unit 106.
The reference signal generation unit 102 reads 8 QAM, 100 Gbaud, and reference information A as items of “modulation scheme”, “baud rate”, and “reference information” on a first row in the reference information table 1061. modulates the read reference information A in a communication condition of 8 QAM and 100 Gbaud, and generates the reference signal 510-1. The reference signal generation unit 102 outputs the generated reference signal 510-1 and information of 8 QAM and 100 Gbaud, which is information of the communication condition corresponding to the reference signal 510-1, to the reference signal transmission unit 103.
Next, the reference signal generation unit 102 reads 16 QAM, 50 Gbaud, and reference information B as the items of “modulation scheme”, “baud rate”, and “reference information” on a second row in the reference information table 1061. The reference signal generation unit 102 modulates the read reference information B in a communication condition of 16 QAM and 50 Gbaud, and generates the reference signal 510-2. The reference signal generation unit 102 outputs the generated reference signal 510-2 and information of 16 QAM and 50 Gbaud, which is information of the communication condition corresponding to the reference signal 510-2, to the reference signal transmission unit 103.
Further, the reference signal generation unit 102 reads 64 QAM, 32 Gbaud, and reference information C as the items of “modulation scheme”, “baud rate”, and “reference information” on a third row in the reference information table 1061. The reference signal generation unit 102 modulates the read reference information C in a communication condition of 64 QAM and 32 Gbaud, and generates the reference signal 510-3. The reference signal generation unit 102. outputs the generated reference signal 510-3 and information of 64 QAM and 32 Gbaud, which is information of the communication condition corresponding to the reference signal 510-3, to the reference signal transmission unit 103.
The reference signal generation unit 102 repeatedly generates a reference signal for all of the reference information A, B, . . . stored in the reference information table 1061, and outputs the generated reference signal and information of a communication condition corresponding to the reference signal to the reference signal transmission unit 103 (step S2).
The reference signal transmission unit 103 obtains the reference signals 510-1, 510-2, 510-3, . . . output by the reference signal generation unit 102 and the information of the communication condition corresponding to each of the reference signals 510-1, 510-2, 510-3, . . . , and generates the first transmission timing notification signal illustrated in
For example, when obtaining the reference signal 510-1 output by the reference signal generation unit 102, the reference signal transmission unit 103 calculates a slot length required for transmission according to a size of the reference signal 510-1. Here, it is assumed that “20” is calculated as the slot length corresponding to the reference signal 510-1.
The reference signal transmission unit 103 obtains information of the modulation scheme of 8 QAM and information of the baud rate of 100 Gbaud as information of the communication condition corresponding to the reference signal 510-1 output by the reference signal generation unit 102. The reference signal transmission unit 103 writes and stores the obtained information of the 8 QAM modulation scheme and the baud rate of 100 Gbaud, and the calculated slot length of “20” in the items of “modulation scheme”, “baud rate”, and “slot length” of the signal information 501.
The reference signal transmission unit 103 inserts the guard time signal 600-1 between the control signal 500 and the reference signal 510-1 to couple the control signal 500 and the reference signal 510-1. The reference signal transmission unit 103 performs the same process as the process performed on the reference signal 510-1, on the reference signals 510-2, 510-3, . . . . Accordingly, the signal information 501 corresponding to the reference signal 510-2 has a modulation scheme of “16 QAM” a baud rate of “50 Gbaud”, and a slot length of “15”. The signal information 501 corresponding to the reference signal 510-3 has a modulation scheme of “64 QAM”, a baud rate of “32 Gbaud”, and a slot length of “15”.
As a length of the guard time signals 600-1, 600-2, 600-3, 600-4, . . . , a signal length corresponding to a sufficient time, when the DSP of the optical transmission and reception apparatus 20b can switch communication conditions, is predetermined. The reference signal transmission unit 103 inserts the guard time signals 600-1, 600-2, 600-3. 600-4, . . . having predetermined lengths.
The reference signal transmission unit 103 finally modulates the control signal 500 in the common communication condition, and generates the first transmission timing notification signal illustrated in
The reference signal detection unit 202 of the optical transmission and reception apparatus 20b receives the first transmission timing notification signal transmitted by the optical transmission and reception apparatus 10b via the optical transmission and reception unit 201. The reference signal detection unit 202 demodulates the control signal 500 of the first transmission timing notification signal in accordance with the common communication condition, and reads information stored in the signal information 501 included in the demodulated control signal 500. While detecting the guard time signal 600-1 following the control signal 500, the reference signal detection unit 202 changes the setting of the DSP from the common communication condition to a communication condition of “8 QAM” and “100 Gbaud” written in a first row in the table of signal information 501.
When detecting an end of the guard time signal 600-1, the reference signal detection unit 202 reads the reference signal 510-1 having 20 slots following the guard time signal 600-1. The reference signal detection unit 202 demodulates the read reference signal 510-1 in accordance with the communication condition of “8 QAM” and “100 Gbaud”.
For example, in the demodulation process, the reference signal detection unit 202 calculates a Bit Error Rate (BER) of the reference signal 510-1, and in a case where the BER is less than or equal to a predetermined threshold value, the reference signal detection unit 202 detects the reference signal 510-1 as a reference signal successfully demodulated. In a case where the reference signal 510-1 is detected as the reference signal successfully demodulated, the reference signal detection unit 202 outputs the reference information A obtained by demodulating the reference signal 510-1 as information related to the reference signal 510-1 to the registration processing unit 203.
In the same manner, the reference signal detection unit 202 detects the guard time signal 600-2 that follows the reference signal 510-1. While detecting the guard time signal 600-2, the reference signal detection unit 202 changes the setting of the DSP from the communication condition of “8 QAM” and “100 Gbaud” to a communication condition of “16 QAM” and “50 Gbaud” written in a second row of the table of signal information 501. When detecting an end of the guard time signal 600-2, the reference signal detection unit 202 reads the reference signal 510-2 having 15 slots following the guard time signal 600-2. The reference signal detection unit 202 demodulates the read reference signal 510-2. in accordance with the communication condition of “16 QAM” and “50 Gbaud”.
In a case where it is determined that the reference signal 510-2 is successfully demodulated, the reference signal detection unit 202 outputs the reference information B obtained from the reference signal 510-2 successfully demodulated, as information related to the reference signal 510-2 to the registration processing unit 203. The reference signal detection unit 202 performs the same process as the process performed on the reference signals 510-1 and 510-2 on the reference signal 510-3 following the reference signal 510-2 and the subsequent reference signals (step S5).
The registration processing unit 203 reads the apparatus ID stored in advance by the storage unit 205, and generates a registration request signal including the read apparatus ID and information related to the reference signal output by the reference signal detection unit 202, that is, the reference information A, B, C, . . . successfully demodulated (step S6). The registration processing unit 203 modulates the generated registration request signal in the common communication condition and transmits the registration request signal to the optical transmission and reception apparatus 10b via the optical transmission and reception unit 201 (step S7).
The communication condition selection unit 104 of the optical transmission and reception apparatus 10b receives the registration request signal transmitted by the optical transmission and reception apparatus 20b via the optical transmission and reception unit 101. The communication condition selection unit 104 demodulates the registration request signal in the common communication condition, and reads the apparatus ID and each of the reference information A, B, C, . . . included in the demodulated registration request signal.
The communication condition selection unit 104 compares each of the reference information A, B, C, . . . included in the registration request signal with the reference information A, B, C, . . . written in the item of “reference information” of the reference information table 1061 stored by the storage unit 106 to detect a record which coincides with the reference information A, B, C, . . . included in the registration request signal. The communication condition selection unit 104 reads, from the detected record, the information of the modulation scheme written in the item of “modulation scheme” corresponding to each of the reference information A, B, C, . . . included in the registration request signal, and a value of the baud rate written in the item of “baud rate”.
The communication condition selection unit 104 selects one of communication conditions indicated by combinations of the information of the read modulation scheme and the value of the baud rate. For example, the communication condition selection unit 104 selects a communication condition with e greatest communication bandwidth. Here, for example, the communication condition selection unit 104 performs the following description when selecting a communication condition with the modulation scheme of “64 QAM” and the baud rate of “32 Gbaud”.
The communication condition selection unit 104 obtains anew registration ID, and writes the apparatus ID included in the registration request signal, the obtained registration ID, and information of the selected communication condition in a corresponding item in the registration information table 1062 of the storage unit 106 to register the optical transmission and reception apparatus 20b (step S8).
The communication condition selection unit 104 generates a registration notification signal including the registration ID and the selected communication condition, modulates the generated registration notification signal in the common communication condition, and transmits the registration notification signal to the optical transmission and reception apparatus 20b via the optical transmission and reception unit 101 (step S9).
The communication condition obtainment unit 204 of the optical transmission and reception apparatus 20b receives the registration notification signal transmitted by the optical transmission and reception apparatus 10b via the optical transmission and reception unit 201. The communication condition obtainment unit 204 demodulates the received registration notification signal in the common communication condition, and reads the registration ID and the information of the communication condition, selected by the communication condition selection unit 104, included in the demodulated registration notification signal. The communication condition obtainment unit 204 writes and stores the read registration ID and information of the communication condition in the storage unit 205 (step S10).
The transmission condition transmission unit 105 of the optical transmission and reception apparatus 10b reads the information of the communication condition corresponding to the optical transmission and reception apparatus 20b registered in the storage unit 106. Here, as described above, the storage unit 106 stores the communication condition with the modulation scheme “64 QAM” and the baud rate of “32 Gbaud” as a communication condition corresponding to the optical transmission and reception apparatus 20b. Thus, the transmission condition transmission unit 105 reads the 64 QAM and 32 Gbaud.
The transmission condition transmission unit 105 calculates a communication bandwidth allocated to the optical transmission and reception apparatus 20b and a transmission timing. Based on the calculated communication bandwidth and the read communication condition with 64 QAM and 32 Gbaud, the transmission condition transmission unit 105 calculates a slot length to be allocated to the optical transmission and reception apparatus 20b. The transmission condition transmission unit 105 writes and stores the calculated slot length and information of the transmission timing in the registration information table 1062 of the storage unit 106 in association with the optical transmission and reception apparatus 20b. The transmission condition transmission unit 105 modulates the second transmission timing notification signal including the calculated slot length and the information of the transmission timing in the common communication condition and transmits the second transmission timing notification signal to the optical transmission and reception apparatus 20b via the optical transmission and reception unit 101 (step S11).
The transmission condition transmission unit 105 dynamically calculates the communication and the transmission timing for the optical transmission and reception apparatus 20b according to the amount of data transmitted by the optical transmission and reception apparatus 20b, in accordance with Dynamic Bandwidth Allocation (DBA), for example.
The data transmission and reception unit 206 of the optical transmission and reception apparatus 20b receives the second transmission timing notification signal transmitted by the optical transmission and reception apparatus 10b via the optical transmission and reception unit 201 (step S12). The data transmission and reception unit 206 demodulates the second transmission timing notification signal in the common communication condition, and reads the slot length and the information of the transmission timing from the demodulated second transmission timing notification signal.
The data transmission and reception unit 206 of the optical transmission and reception apparatus 20b generates a reception response signal including the registration ID of the own apparatus stored in the storage unit 205, modulates the generated reception response signal in the common communication condition, and transmits the reception response signal to the optical transmission and reception apparatus 10b via the optical transmission and reception unit 201 (step S13). The data transmission and reception unit 107 of the optical transmission and reception apparatus 10b receives the reception response signal transmitted by the optical transmission and reception apparatus 20b via the optical transmission and reception unit 101. The data transmission and reception unit 107 demodulates and obtains the received reception response signal in the common communication condition, and in a communication state in which data transmission and. reception is performed with the data transmission and reception unit 206 of the optical transmission and reception apparatus 20b at the communication condition selected by the communication condition selection unit 104 (step S14).
As a result, as illustrated in
In the configuration of the second embodiment described above, a. case where the optical transmission and reception apparatus 20b transmits data to the optical transmission and reception apparatus 10b will be described. The data transmission and reception unit 206 of the optical transmission and reception apparatus 20b reads a communication condition stored in the storage unit 205, that is, the communication condition of 64 QAM and 32 Gbaud, and sets the communication condition to the DSP. The data transmission and reception unit 206 modulates transmission data to be transmitted to the optical transmission and reception apparatus 10b in accordance with the communication condition of 64 QAM and 32 Gbaud.
The data transmission and reception unit 206 selects transmission data of a size corresponding to a slot length read from the second transmission timing notification signal, from the modulated transmission data. The data transmission and reception unit 206 transmits the selected transmission data to the optical transmission and reception apparatus 10b via the optical transmission and reception unit 201 at a time indicated by a transmission timing read from the second transmission timing notification signal. As illustrated in
The data transmission and reception unit 107 of the optical transmission and reception apparatus 10b receives the transmission data transmitted by the optical transmission and reception apparatus 20b via the optical transmission and reception unit 101. With reference to the registration information table 1062 of the storage unit 106, the data transmission and reception unit 107 reads reception data of a length of the corresponding “slot length” for each time written to the item of “transmission timing”. The data transmission and reception 107 switches the communication condition used for demodulation of the reception data set to DSP into a communication condition indicated by the items of the corresponding “modulation scheme” and “baud rate”, for each time written to the item “transmission timing”. The data. transmission and reception unit 107 demodulates the reception data received from the optical transmission and reception apparatus 20b in the communication condition switched in accordance with the transmission timing, and obtains the transmission data transmitted. by the optical transmission and reception apparatus 20b.
In the configuration of the second embodiment described above, a case where the optical transmission and reception apparatus 10b transmits data to the optical transmission and reception apparatus 20b will be described. When transmission data to be transmitted to the optical transmission and reception apparatus 20b is generated, the data transmission and reception unit 107 of the optical transmission and reception apparatus 10b refers to the registration information table 1062 of the storage unit 106, reads a registration ID corresponding to the optical transmission and reception apparatus 20b and a communication condition having a modulation scheme of 64 QAM and a baud rate of 32 Gbaud, and sets the read communication condition to the DSIP.
The data transmission and reception unit 107 modulates the transmission data to be transmitted to the optical transmission and reception apparatus 20b in the read communication condition. A downlink direction is a TDM scheme. so that a slot is allocated in advance for each registration ID. Thus, the data transmission and reception unit 107 writes the modulated transmission data to a slot corresponding to the read registration ID, and transmits the transmission data via the optical transmission and reception unit 101. As illustrated in
The data transmission and reception unit 206 of the optical transmission and reception. apparatus 20b receives the transmission data transmitted by the optical transmission and reception apparatus 10b via the optical transmission and reception unit 201 as reception data, and reads the reception data written in the slot corresponding to the registration ID allocated to the own apparatus in the reception data. The data transmission and reception unit 206 reads the communication condition having 64 QAM and 32 Gbaud stored by the storage unit 205, set to the DSP, demodulates the reception data, and obtains the transmission data transmitted by the optical transmission and reception apparatus 10b.
According to the configuration of the second embodiment described above, by modulating the data based on each candidate of the communication condition transmittable and receivable by the own apparatus, the reference signal generation unit 102 of the optical transmission and reception apparatus 10b generates the plurality of reference signals 510-1, 510-2, . . . corresponding to each candidate for the communication condition. The reference signal transmission unit 103 transmits the plurality of reference signals 510-1, 510-2, . . . generated by the reference signal generation unit 102 and information of the communication condition corresponding to the plurality of reference signals 510-1, 510-2, . . . to the optical transmission and reception apparatus 20b. The reference signal detection unit 202 of the optical transmission and reception apparatus 20b receives the plurality of reference signals 510-1, 510-2, . . . and the information of the communication condition corresponding to the plurality of reference signals 510-1, 510-2, . . . transmitted from the optical transmission and reception apparatus 10b, demodulates the received plurality of reference signals 510-1, 510-2, . . . based on the communication condition corresponding to the plurality of reference signals 510-1, 510-2, . . . , and detects the reference signals 510-1, 510-2, . . . successfully demodulated. The registration processing unit 203 transmits a. registration request signal including the information related to the reference signals 510-1, 510-2, . . . detected by the reference signal detection unit 202 to the optical transmission and reception apparatus 10b. The communication condition selection unit 104 of the optical transmission and reception apparatus 10b selects a communication condition for transmission and reception with the optical transmission and reception apparatus 20b based on the information related to the reference signals 510-1, 510-2, . . . detected by the reference signal detection unit 202 of the optical transmission and reception apparatus 20b. The optical transmission and reception apparatus 10b and the optical transmission and reception apparatus 20b transmit and receive optical signals in accordance with the communication condition selected by the communication condition selection unit 104. As a result, a result of successful demodulation of the reference signals 510-1, 510-2, . . . indicates a condition of a transmission line between the optical transmission and reception apparatus 10b and the optical transmission and reception apparatus 20b. Thus, when the communication condition selection unit 104 selects a communication condition corresponding to the reference signals 510-1, 510-2, successfully demodulated, in accordance with a transmission line condition for each of the optical transmission and reception apparatuses 20b-1 to 20b-N which are grounds, it is possible to select an appropriate communication condition for each of the optical transmission and reception apparatuses 20b-1 to 20b-N. Accordingly, in the optical transmission system 2 which performs 1-to-N transmission and reception of optical signals, an appropriate communication condition can be selected for each ground in accordance with a transmission line condition for each ground.
In the configuration of the second embodiment described above, the registration processing unit 203 of the optical transmission and reception apparatus 20b includes reference information corresponding to a reference signal detected by the reference signal detection unit 202 in a registration request signal as information related to the reference signal and transmits the registration request signal to the optical transmission and reception apparatus 10b but the configuration of the present disclosure is not limited to the embodiment described above. For example, it is assumed that the reference information table 1061 of the storage unit 106 of the optical transmission and reception apparatus 10b stores the modulated and generated reference signal in addition to the reference information. In this case, the registration processing unit 203 may include the reference signal detected by the reference signal detection unit 202 in the registration request signal as information related to the reference signal and transmit the registration request signal to the optical transmission and reception apparatus 10b. In this case, the communication condition selection unit 104 of the optical transmission and reception apparatus 10b is configured to detect a corresponding communication condition from the reference information table 1061 based on the reference signal. Without including the reference information and the reference signal in the registration request signal, the reference signal detection unit 202 may include the information related to the communication condition successfully demodulated in the registration request signal as information related to the reference signal and transmit the registration request signal to the optical transmission and reception apparatus 10b. In this case, the communication condition selection unit 104 may select any one communication condition among the communication conditions included in the received registration request signal.
Further, in the configuration of the second embodiment described above, the communication condition selection unit 104 of the optical transmission and reception apparatus 10b selects the communication condition, but the configuration of the present disclosure is not limited to the embodiment described above. The reference signal detection unit 202 or the registration processing unit 203 of the optical transmission and reception apparatus 20b may select one of the communication conditions and include information of the selected communication condition in the registration request signal, and transmit the registration request signal to the communication condition selection unit 104 of the optical transmission and reception apparatus 10b. In this case, the communication condition selection unit 104 of the optical transmission and reception apparatus 10b sets one communication condition included in the registration request signal as a communication condition with the optical transmission and reception apparatus 20b.
In the configuration of the second embodiment described above, in step S9 illustrated in
Further, in the configuration of the second embodiment described above, in step S5 in
In the configuration of the second embodiment described above, a combination of both of the modulation scheme and the baud rate is applied as a communication condition, but the configuration of the present disclosure is not limited to the embodiments described above. For example, a combination in which the baud rate is a fixed value and only the modulation scheme is variable may be used as the communication condition, or a combination in which the modulation scheme is fixed and only the baud rate is a variable value may be used as the communication condition.
In the first transmission timing notification signal illustrated in
Further, the configuration of the second embodiment described above may be applied to the configuration in
Further, in the second embodiment, the first transmission timing notification signal in the format illustrated in
The first transmission timing notification signal illustrated in
With the format as illustrated in
In the first transmission timing notification signal in the format in
The first transmission timing notification signal illustrated in
For example, a length of a cycle of the control signal 500b-1 is a length obtained by adding a length of the control signal 500b-1, a slot length of the reference signal 510b-1, and lengths of the guard time signals 600b-1s and 600b-1e. In the same manner, a length of a cycle of a control signal 500b-2 is a length obtained by adding a length of the control signal 500b-2, a slot length of the reference signal 510b-2, and lengths of guard time signals 600b-2s and 600b-2e.
With the format illustrated in
In the format in
In the second embodiment described above, the first transmission timing signal is illustrated in
In the same manner as the configuration illustrated in
In the same manner as the configuration illustrated in
As illustrated in
For example, the format illustrated in
In addition, the format illustrated in
In addition, the format illustrated in
The format illustrated in
The format illustrated in
In the first and second embodiments, any one of 8 QAM, 16 QAM, and 64 QAM is described as a modulation scheme, but the configuration of the present disclosure is not limited to the embodiment described above. Quadrature amplitude modulation other than 8, 16, and 64 may be applied, or another modulation scheme such as polarization multiplexing QSPK may be applied.
In the first and second embodiments described above, N, which is the number of the optical transmission and reception apparatuses 20-1 to 20-N and 20b-1 to 20b-N on the ground side, may be “1” as the minimum configuration, but in the case of N=1, since the configuration is a 1-to-1 configuration, the configuration may not be provided with the optical multiplexer-demultiplexer 40 and the optical passive elements 45-1 to 45-10.
The optical transmission and reception apparatuses 10, 10b, 20-1 to 20-N, 20b, and 20b-1 to 20b-N according to the above-described embodiment may be realized by a computer. In this case, a program for realizing the functions is recorded on a computer-readable recording medium, and the functions may be realized by reading the program recorded on the recording medium into a computer system and executing the program. The “computer system” here includes an OS or hardware such as a peripheral device. The “computer-readable recording medium” is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM or a storage device such as a hard disk embedded in the computer system. The “computer readable recording medium” may be a medium which dynamically holds programs for a short period, such as a communication line in a case of transmitting the program via a network such as the Internet or a communication line such as a telephone line or a medium which holds the program for a certain period, such as a volatile memory inside the computer system which becomes a server or a client in this case. The program may be for realizing some of the functions described above, may be a program which can realize the functions described above in combination with the program already recorded in the computer system, or may be realized by using a programmable logic device such as a Field Programmable Gate Array (FPGA).
The present embodiments are described above with reference to the drawings, but a specific configuration is not limited to the embodiments and may he implemented in various modes without departing from a gist thereof,
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-047277 | Mar 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/008101 | 3/1/2019 | WO | 00 |
