JP5900222B2 - Relay device - Google Patents

Description

  The present invention relates to a relay device that relays data transmitted from a transmission device to a reception device.

  With the widespread use of mobile terminal devices such as smartphones, tablet PCs (Personal Computers), and notebook PCs, it is becoming an issue to realize smooth data transmission and reception and to reduce terminal power consumption when downloading data.

  On the other hand, the broadbandization of communication networks has progressed, and wired broadband systems such as FTTH (Fiber To The Home) and ADSL (Asymmetric Digital Subscriber Line), and wireless such as 3G, LTE, WiMAX, WiFi, Bluetooth (registered trademark), and ZigBee A broadband system has been established. In such a broadband system, when a user acquires data from a Web server (transmitting device) through a terminal device (receiving device), the following processing is generally performed. When the user is instructed to acquire data from the Web server, the terminal device transitions from the standby state to the normal state, and transmits a data acquisition request to the Web server. Here, the normal state is a state in which data transmission / reception is possible, and the standby state is a state in which data transmission / reception is impossible and power consumption is less than that in the normal state. When a data acquisition request is sent from the terminal device, the Web server transmits the requested data to the terminal device. The terminal device receives data sent from the Web server, and after receiving all data, transitions from the normal state to the standby state.

  Further, when data is transferred between a transmission device and a reception device having different communication speeds, it is generally performed to transfer data via a buffer (see, for example, Patent Document 1). The technique described in Patent Document 1 is a technique for transferring data via a buffer when the communication speed of a transmission apparatus is slower than the communication speed of a reception apparatus. Referring to FIG. 14, in Patent Document 1, first, at time T0, data transfer between a transmission device having a low communication speed and a buffer is started in response to a data acquisition request from the reception device, and data is written to the buffer. . Thereafter, at time T1 when data of the data amount Px is accumulated in the buffer, reading of data from the buffer is started, and the read data is transferred to the receiving device. After time T1, writing data to the buffer and reading data from the buffer are performed in parallel. Note that the time T1 at which reading of data from the buffer is started is determined so that the data transfer at the receiving device side does not overtake the data writing on the transmitting device side, and the data transfer ends at the same time at time T2. By doing so, it is possible to shorten the communication time of the receiving apparatus necessary for receiving data of the data amount Tmax, compared to the case where reading of data from the buffer is started at time T0. The communication time when data reading from the buffer is started at time T0 is (T2-T0), and the communication time when data reading from the buffer is started at time T1 is (T2-T1).

JP 2007-323661 A

  According to the technique described in Patent Literature 1, when the communication speed of the transmission device is slower than the communication speed of the reception device, the communication time of the reception device required to receive data of the data amount Pmax is (T2 -T1). However, the technique described in Patent Document 1 has a problem that it is difficult to sufficiently reduce the power consumption of the receiving apparatus. As described above, generally, when acquiring data from a transmitting device, a receiving device makes a data acquisition request after changing the state of the own device from a standby state to a communication state with high power consumption. Until the reception of data is completed, the state of the own device is set to the communication state. For this reason, even during a period when data is not actually transmitted / received (time T0 to T1), the state of the receiving device becomes a communication state with high power consumption, so it is difficult to sufficiently reduce power consumption. .

[Object of the present invention]
Accordingly, an object of the present invention is to provide a relay device that solves the problem that it is difficult to sufficiently reduce the power consumption of the receiving device when the communication speed on the transmitting device side is slower than the communication speed on the receiving device side. It is in.

The relay device according to the present invention is
For each session that passes through the own relay device, when a session is established with the transmission device, triggered by a data acquisition request made to the transmission device, data transmission / reception is performed. The data transferred from the transmitting device is generated in the buffer area for the receiving device that makes a transition from the possible normal state to the power saving state in which data transmission / reception is impossible and power consumption is lower than the normal state. Data storage means for storing in the session buffer;
Schedule means for calculating a transfer start timing, which is a timing at which preparation for transferring data stored in the buffer for the session is completed for each session passing through the own relay device;
For each session that passes through the own relay device, at the transfer start timing calculated by the scheduling unit for the session, a state control unit that transitions the state of the receiving device of the session from the power saving state to the normal state;
A data transfer unit that starts data transfer from the buffer for the session to the receiving device of the session at the transfer start timing calculated by the schedule unit for each session passing through the own relay device; Is provided.

The receiving apparatus according to the present invention is
When a session via the relay device is established with the transmission device triggered by a data acquisition request made from the reception device to the transmission device, the normal state in which the state of the reception device can transmit and receive data When receiving a state transition instruction sent from the relay device, the state of the own receiving device is changed from the power saving state to the normal state. State switching means for transitioning to a state is provided.

The relay system according to the present invention is
A relay system for transferring data from a transmission device to a reception device via a relay device,
The relay device is
For each session passing through the own relay device, data storage means for storing data transferred from the session transmission device to the session reception device in a buffer for the session;
Schedule means for calculating a transfer start timing, which is a timing at which preparation for transferring data stored in the buffer for the session is completed for each session passing through the own relay device;
A data transfer unit that starts data transfer from the buffer for the session to the receiving device of the session at the transfer start timing calculated by the schedule unit for each session passing through the own relay device; With
The receiving device is:
When a session is established with the transmission device triggered by a data acquisition request made to the transmission device, the state of the own reception device cannot be transmitted / received from a normal state where data transmission / reception is possible. State switching means for making a transition to a power saving state in which the power consumption is less than that in the normal state and causing the state of the own receiving apparatus to transition from the power saving state to the normal state at the transfer start timing calculated by the scheduling means is provided.

The relay method according to the present invention is:
When the data storage means is a receiving device of the session for each session passing through the own relay device, and a session is established with the transmitting device triggered by a data acquisition request made to the transmitting device The data transferred from the transmitting device to the receiving device that transitions from the normal state in which data can be transmitted / received to the power saving state in which data transmission / reception is impossible and power consumption is lower than the normal state is stored in the buffer area. Accumulates in the session buffer generated above,
For each session that passes through the relay device, the scheduling means calculates the transfer start timing, which is the timing when the data stored in the session buffer is ready for transfer,
For each session that passes through the own relay device, the state control unit causes the receiving device state of the session to transition from the power saving state to the normal state at the transfer start timing calculated for the session by the scheduling unit. ,
The data transfer means starts data transfer from the session buffer to the receiving apparatus of the session at the transfer start timing calculated for the session by the scheduling means for each session passing through the own relay apparatus. To do.

The program according to the present invention is:
Computer
For each session that passes through the relay device, when the session is established with the transmission device, triggered by a data acquisition request made to the transmission device, data can be transmitted and received The data transferred from the transmitting device is generated in the buffer area for the receiving device that is incapable of transmitting and receiving data from the normal state and transitions to the power saving state that consumes less power than the normal state. Data storage means for storing in the session buffer,
Schedule means for calculating a transfer start timing, which is a timing at which preparation for transferring data stored in the buffer for the session is completed for each session passing through the relay device;
For each session passing through the relay device, at the transfer start timing calculated by the scheduling unit for the session, a state control unit that transitions the state of the receiving device of the session from the power saving state to the normal state;
As data transfer means for starting data transfer from the session buffer to the receiving apparatus of the session at the transfer start timing calculated by the schedule means for the session for each session passing through the relay device Make it work.

  According to the present invention, even when the communication speed between the transmission apparatus and the relay apparatus is slower than the communication speed between the relay apparatus and the reception apparatus, the power consumption of the reception apparatus can be sufficiently reduced. Can do.

It is a block diagram which shows the structural example of the relay system concerning the 1st Embodiment of this invention. 3 is a block diagram illustrating a configuration example of a relay device 300. FIG. 6 is a diagram illustrating an example of contents of a schedule storage unit 322. FIG. 3 is a block diagram illustrating a configuration example of a receiving device 400. FIG. FIG. 11 is a diagram illustrating a state in which the state of the reception device 400 changes. 4 is a flowchart showing a processing example of a schedule unit 312. It is a figure for demonstrating the transfer start timing of data. It is a flowchart which shows the process example of the state control means 313. 10 is a flowchart illustrating an example of processing of a data transfer unit 314. It is a figure which shows the structural example of the relay apparatus 300a concerning the 2nd Embodiment of this invention. It is a flowchart which shows a part of process performed by the schedule means 312a. It is a flowchart which shows the remaining part of the process performed by the schedule means 312a. It is a figure for demonstrating the process performed by the schedule means 312a. It is a figure for demonstrating the technique described in patent document 2. FIG. 6 is a diagram illustrating an example of contents of a schedule storage unit 322. FIG. 4 is a flowchart showing a processing example of a schedule unit 312. 4 is a flowchart showing a processing example of a schedule unit 312. It is a flowchart which shows the process example of the state control means 313. 10 is a flowchart illustrating an example of processing of a data transfer unit 314.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

[First embodiment of the present invention]
Referring to FIG. 1, a first embodiment of a relay system 100 according to the present invention includes a transmission device 200, a relay device 300, a reception device 400, a communication network 500 including a WAN, a dedicated line, and the like. , FTTH, ADSL, 3G, LTE, WiMAX, WiFi, Bluetooth, ZigBee, and the like. Although only one receiving device 400 is shown in FIG. 1, the number of receiving devices may be plural.

  In the present embodiment, a configuration in which transmission device 200 transmits data to reception device 400 via relay device 300 (configuration in which reception device 400 downloads data from transmission device 200 via relay device 300) will be described. To do.

  In this embodiment, the receiving device 400 can be various electronic devices such as a personal computer (PC), a smartphone, a tablet PC, and a notebook PC.

  In the relay system 100, when the user attempts to execute Web browsing, data acquisition, etc. through the receiving device 400, the receiving device 400 communicates with the communication partner (transmitting device 200) via the communication network 500. The relay apparatus 300 secures a communication path (connection) between the relay apparatus 300 and the transmission apparatus 200, and finally communication (session) between the reception apparatus 400 and the transmission apparatus 200 is established. The

  In such a relay system 100, when the communication speed between the transmission apparatus 200 and the relay apparatus 300 is extremely lower than the communication speed between the relay apparatus 300 and the reception apparatus 400, Patent Document 1 is cited as the relay apparatus 300. If the relay device described in the above is used, the communication time is unnecessarily prolonged, and the power consumption of the receiving device 400 increases.

  Therefore, in this embodiment, the power consumption of receiving apparatus 400 is reduced by adopting the following configuration.

When a session is established between the transmission device 200 and the reception device 400, the reception device 400 changes from a normal state (a state where data can be transmitted / received) to a power saving state (a state where power transmission / reception is impossible and power consumption is normal) Transition to less state).
The relay apparatus 300 includes a buffer and temporarily stores data transmitted from the transmission apparatus 200 to the reception apparatus 400 in the buffer.
The relay device 300 simultaneously ends the data transfer from the transmission device 200 to the relay device 300 and the data transfer from the relay device 300 to the reception device 400 at the transfer start timing of the data stored in the buffer. The transfer start timing that can be executed is calculated.
The relay device 300 controls the receiving device 400 to transition from the power saving state to the normal state at the transfer start timing, and starts transferring the data stored in the buffer.

[Configuration of Relay Device 300]
Referring to FIG. 2, the relay device 300 includes a control unit 310, a storage device 320, and a communication unit 330.

  The communication unit 330 has a function of connecting to various communication devices including the transmission device 200 and the reception device 400 via the communication network 500 and the access line 600 and transmitting / receiving data.

  The storage device 320 includes a ROM, RAM, EEPROM, nonvolatile RAM, flash memory, disk, and the like, and includes a buffer area 321 and a schedule storage unit 322.

  In the buffer area 321, there is a buffer for temporarily storing data of each session established between the transmission device 200 and the reception device (not limited to the reception device 400 shown in FIG. 1). Generated.

  In the schedule storage unit 322, for each session passing through the relay device 300, the transfer start timing of data accumulated in the buffer for the session and the transmission timing of the state transition instruction are recorded. FIG. 3 is a diagram showing an example of the contents of the schedule storage unit 322. For example, in the first row of the figure, the session with the session ID “# 1” has the transfer start timing “t1, a” and the transmission timing. Indicates “t1, b”.

  The control unit 310 includes a data storage unit 311, a schedule unit 312, a state control unit 313, and a data transfer unit 314.

  When the session is established between the transmission device 200 and the reception device (for example, the reception device 400), the data storage unit 311 generates a buffer corresponding to the session on the buffer area 321 or from the transmission device 200. It has a function of accumulating data sent to the receiving apparatus 400 in the buffer.

  When a new session (new session) is established, the scheduling means 312 determines the transfer start timing of data stored in a buffer corresponding to the new session and the already established existing session, and the session. And a function for calculating the transmission timing of the state transition instruction to the receiving device related to the, and a function for recording the calculated transfer start timing and transmission timing in the schedule storage unit 322 in association with the session ID. A specific method for calculating the transfer start timing and the transmission timing will be described in detail later.

  Based on the content of the schedule storage unit 322, the state control unit 313 determines whether or not there is a session that has reached the transmission timing of the state transition instruction, and if there is a session that has reached the transmission timing, Has a function of transmitting a state transition instruction to the receiving device.

  Based on the content of the schedule storage unit 322, the data transfer unit 314 determines whether or not there is a session that has reached the data transfer start timing, and if there is a session that has reached the transfer start timing, Has a function of starting the transfer of data stored in the buffer corresponding to.

  The relay device 300 can be realized by a computer, and in that case, for example, the following is performed. A disk, a semiconductor memory, and other recording media on which a program for causing a computer to function as the data storage unit 311, the schedule unit 312, the state control unit 313, and the data transfer unit 314 are prepared, and the computer reads the program. Make it. The computer realizes the above-described units 311 to 314 on its own computer by controlling its own operation according to the read program.

[Configuration of Receiving Device 400]
Referring to FIG. 4, the receiving apparatus 400 includes a communication unit 410, a control unit 420, an input unit 430 such as a keyboard, and an output unit 440 such as an LCD and a speaker.

  The communication unit 410 has a function of transmitting / receiving data via the communication network 500 and the access line 600.

  The control unit 420 includes a download unit 421, a state switching unit 422, and a state transition instruction detection unit 423.

  The download unit 421 has a function of transmitting a download request to the transmission device 200 via the relay device 300 in accordance with a user instruction input from the input unit 430, and has been sent from the transmission device 200 in response to the download request. It has a function of outputting data to the output unit 440.

  When the session is established between the receiving device 400 and the transmitting device 200, the state switching unit 422 is configured to change the state of the receiving device 400 from the normal state to the power saving state or according to the instruction from the state transition instruction detecting unit 423. The receiver 400 has a function of transitioning the state of the receiving device 400 from the power saving state to the normal state.

  When the state transition instruction detection unit 423 detects the state transition instruction sent from the state control unit 313 in the relay apparatus 300, the state transition instruction detection unit 423 changes the state of the reception apparatus 400 from the power saving state to the normal state with respect to the state switching unit 422. The function of instructing to switch to is provided.

  The receiving device 400 can be realized by a computer, and when realized by a computer, for example, is as follows. A disk, a semiconductor memory, and other recording media on which a program for causing the computer to function as the download unit 421, the state switching unit 422, and the state transition instruction detection unit 423 are prepared, and the computer reads the program. The computer realizes the above-described means 421 to 423 on its own computer by controlling its own operation according to the read program.

[Operation of First Embodiment]
Next, the operation of the present embodiment will be described in detail.

  When downloading data, the download unit 421 in the reception device (for example, the reception device 400) transmits a download request (data acquisition request) to the transmission device 200 via the relay device 300. In response to this, when a new session (new session) is established between the transmission apparatus 200 and the reception apparatus 400 via the relay apparatus 300, the state switching unit 422 receives the reception as shown in FIG. The state of the device 400 is changed from the normal state to the power saving state (time t1). In addition, the normal state and the power saving state are specifically the active state and idle state in the mobile terminal communication standard Long Term Evolution (LTE) standardized by 3GPP (Third Generation Partnership Project), IEEE (The Institute of It can correspond to the active mode and power save mode in IEEE 802.11 established by Electrical and Electronics Engineers). Note that after the session is established, the transmission device 200 starts transferring data requested from the reception device 400.

  On the other hand, when the new session is established, the data storage unit 311 in the relay apparatus 300 generates a buffer for the new session in the buffer area 321. Thereafter, the data storage unit 311 stores the data (contents) of the new session sent from the transmission device 200 in the session buffer. When the new session is established, (n-1) sessions (existing sessions) having session IDs # 1 to # (n-1) are already established, and the session ID “#” is included in the new session. It is assumed that “n” is given. In the following description, a session with a session ID “#i” may be referred to as session #i.

  Further, when the new session #n is established, the scheduling unit 312 in the relay apparatus 300 performs the process shown in the flowchart of FIG.

  In step S61, the communication speeds W1, s to Wn, s between the transmission device 200 and the relay device 300 are obtained for each session # 1 to #n. Specifically, for sessions # 1 to # (n-1) in which data transfer is started, communication speeds W1, s to W (n-1), s are actually measured. For session #n in which data transfer has not started, the communication speed Wn, s is obtained by performing the calculation shown in the following equation (1).

Wn, s = {total value of communication speeds W1, s to W (n-1), s of existing sessions # 1 to # (n-1)}
÷ (Number of established sessions n) (1)

  In step S62, the communication speeds W1, d to Wn, d between the relay device 300 and the receiving device are obtained for each session # 1 to #n. Specifically, when the session #i (1 ≦ i ≦ n) is a session that has already started data transfer from the relay device 300 to the receiving device, the communication speed Wi, d is actually measured. When session #i is a session in which data transfer from the relay apparatus 300 to the receiving apparatus has not started, the communication speed Wi, d is calculated by performing the calculation shown in the following equation (2).

Wi, d = (total value of communication speeds of sessions starting data transfer to the relay device)
÷ (Number of sessions starting data transfer to relay device) (2)

  In step S63, reception times T1, s to Tn, s until the relay device 300 finishes receiving data from the transmission device 200 are obtained for each session # 1 to #n. Specifically, when the session #i is a session that is receiving data from the transmission apparatus 200, the reception time Ti, s is obtained by performing the calculation shown in the following equation (3). When session #i is a session that has not started receiving data from transmitting apparatus 200, the reception time Ti, s is obtained by performing the calculation shown in the following equation (4).

Ti, s = (Si-Si, s) / Wi, s (3)
Ti, s = Si ÷ Wi, s (4)

  In equations (3) and (4), Si is the data size of the data to be transferred in session #i (notified from transmission device 200), and Si, s has been received by relay device 300 via session #i. , Wi, s indicates the communication speed between the transmission apparatus 200 and the relay apparatus 300 in session #i.

  In step S64, for each session that has not started data transfer to the receiving device, the transfer time until the relay device 300 finishes transferring data to the receiving device (the transfer time of session #i is denoted as Ti, d). Ask. Specifically, the transfer time Ti, d is obtained by performing the calculation shown in the following equation (5).

  Ti, d = Si ÷ Wi, d (5)

  In step S65, for each session that has not started data transfer to the receiving device, data transfer start timing (the transfer start timing of session #i is denoted as ti, a) and state transition instruction transmission timing (session #) i is expressed as ti, b). Specifically, the transfer start timing ti, a and the transmission timing ti, b of the session #i are obtained by performing calculations shown in the following equations (6) and (7).

ti, a = current time + Ti, s-Ti, d (6)
ti, b = ti, a-Ci (7)

  Here, as can be seen with reference to FIG. 7, in the equation (6), the transmission device 200 and the relay device in the session #i are used as the transfer start timing ti, a of the data stored in the session #i buffer. The time at which the data transfer between the relay device 300 and the data transfer between the relay device 300 and the reception device in the session #i can be completed simultaneously is obtained. Therefore, by starting the data transfer from the relay device 300 to the receiving device at the transfer start timing ti, a obtained by the equation (6), the communication time of the session #i is set to be the same as when no buffer is used. And the communication time between the relay device and the receiving device can be minimized. In Expression (7), Ci represents the time (transition time) required for the receiving device of session #i to transition from the power saving state to the normal state.

  In step S66, the transfer start timing and transmission timing of each session obtained in step S65 are recorded in the schedule storage unit 322 in association with the session ID. For a session in which the session ID has already been recorded in the schedule storage unit 322, the transfer start timing and transmission timing recorded in association with the session ID are replaced with those obtained this time, and the session ID is stored in the schedule storage unit 322. For the sessions not recorded in the above, the transfer start timing and transmission timing obtained this time associated with the session ID are recorded. The above is the processing performed by the schedule unit 312.

  Next, the operation of the state control means 313 will be described with reference to the flowchart of FIG.

  First, the state control unit 313 pays attention to one of the currently established sessions (for example, session # 1) (step S81). Thereafter, the state control unit 313 searches the schedule storage unit 322 for the transmission timing related to the session # 1 currently focused on, and compares the searched transmission timing with the current time (step S82).

  If the current time is equal to the transmission timing or has passed the transmission timing (Yes in step S82), a state transition instruction is transmitted to the receiving device (for example, the receiving device 400) related to the session # 1. (Step S83), then, the session of interest is changed to another session (Step S84), and the process of Step S82 is performed again. When the state transition instruction detecting unit 423 in the receiving apparatus 400 receives the state transition instruction sent from the relay apparatus 300, the state transition instruction detecting unit 423 issues an instruction to the state switching unit 422, and changes the state of the receiving apparatus 400 from the power saving state to the normal state. Transition to the state (time t2 in FIG. 5). Specifically, the state transition instruction can correspond to a communication request message in LTE standardized by 3GPP or a DTIM (Delivery Traffic Indication Message) in IEEE 802.11 established by IEEE.

  On the other hand, if the current time is earlier than the transmission timing (No in step S82), the state control unit 313 changes the session of interest to another session (step S84), and then repeats the process of step S82. I do.

  Next, the operation of the data transfer means 314 will be described with reference to the flowchart of FIG.

  First, the data transfer unit 314 pays attention to one of the currently established sessions (for example, session # 1) (step S91). Thereafter, the data transfer unit 314 searches the schedule storage unit 322 for the transfer start timing related to the session # 1 currently focused on, and compares the searched transfer start timing with the current time (step S92).

  If the current time is equal to the transfer start timing or has passed the transfer start timing (Yes in step S92), the data transfer process from the buffer for session # 1 to the receiving device is started and the schedule is stored. The information related to session # 1 recorded in unit 322 is deleted (step S93). At this point, since the receiving device has transitioned to a normal state in which data can be transmitted and received, the data transmitted from the relay device 300 is received by the communication unit 410 and output to the output unit 440 by the download unit 421. The Thereafter, the data transfer unit 314 changes the session of interest to another session (step S94), and performs the process of step S92 again. Note that the data transfer process from the relay apparatus 300 to the reception apparatus is completed at time t3 as shown in FIG. 5, and the data transfer process from the transmission apparatus 200 to the relay apparatus is also completed at time t3.

  On the other hand, if the current time is earlier than the transfer start timing (No in step S92), the session of interest is changed to another session (step S94), and the process of step S92 is performed again.

  In the above description, the time at which data transfer from the relay device to the receiving device is started is the data transfer start timing. However, the time until the data transfer is started may be the data transfer start timing. Good. Further, the relay device 300 may be installed at the boundary between a wired section and a wireless section, such as a wireless LAN access point or a wireless base station. With this configuration, it is possible to perform buffer storage transfer control that more accurately reflects the difference in the band fluctuation characteristics between the wired section and the wireless section (the band fluctuation of the wireless section is greater), so the receiving side can be more effectively It is possible to reduce the communication time and reduce the power consumption of the receiving device caused by communication.

  Further, the contents of the schedule storage unit 322 are as shown in FIG. 15, the schedule means 312 performs the processing shown in the flowcharts of FIG. 16 and FIG. 17, and the state control means 313 performs the processing shown in the flowchart of FIG. The means 314 can perform the processing shown in the flowchart of FIG.

  Referring to FIG. 16, when establishing a new session, the scheduling unit 312 first performs the same processing as steps S <b> 61 to S <b> 65 described above, and starts transfer for each session that has not started data transfer to the receiving device. Timing ti, a and transmission timing ti, b are obtained (step S161).

  Next, as shown in FIG. 15, the scheduling unit 312 includes a set of a time corresponding to the transfer start timing ti, a, a session ID, and a timing type “transfer start timing”, and a time corresponding to the transmission timing ti, b. The session ID and the timing type “transmission timing” are recorded in the schedule storage unit 322 (step S162). For a session whose session ID has already been recorded in the schedule storage unit 322, the time is replaced with the one obtained this time, and for a session whose session ID is not recorded in the schedule storage unit 322, the time, session ID and timing are replaced. A set with a type (information indicating whether it is a transfer start timing or a transmission timing) is recorded in the schedule storage unit 322.

  Thereafter, the schedule unit 312 sorts the combinations of the time, session ID, and timing type recorded in the schedule storage unit 322 in order of time, and the combination including the earliest time is the first in the schedule storage unit 322. The data is stored in the second area (step S163).

  The schedule unit 312 also performs processing shown in the flowchart of FIG. In step S171, the schedule unit 312 determines whether or not the current time is the earliest time recorded in the schedule storage unit 322 (the time recorded in the first area of the schedule storage unit 322). To do. If it is determined that the current time is the earliest time recorded in the schedule storage unit 322 (Yes in step S171), whether the timing type paired with that time is a transmission timing or a transfer start timing. Is determined (step S172).

  If the timing type is transmission timing (Yes in step S172), the session control unit 313 is notified of the session ID included in the set (step S173), and then the schedule storage unit 322 stores the first ID. The information (a set of time, session ID, and timing type) recorded in the first area is deleted (step S175). When the session control unit 313 is notified of the session ID (step S181 in FIG. 18 is Yes), the state control unit 313 transmits a state transition instruction to the receiving device of the session indicated by the session ID (step S182). .

  On the other hand, when the timing type is the transfer start timing (No in step S172), the session ID included in the group is notified to the data transfer unit 314 (step S174), and then the schedule storage is performed. The information recorded in the first area of the part 322 is deleted (step S175). When the session ID is notified from the schedule unit 312 (Yes in step S191 in FIG. 19), the data transfer unit 314 starts data transfer from the buffer corresponding to the notified session ID (step S192).

  According to the processing shown in the flowcharts of FIGS. 16 to 19 described above, the load can be reduced compared to the processing shown in the flowcharts of FIGS. 6, 8, and 9. That is, since it is only necessary to monitor the information recorded in the first area of the schedule storage unit 322, the data of all sessions recorded in the schedule storage unit 322 must be monitored. FIG. The load can be reduced as compared with the processing shown in the flowcharts of FIGS.

[Effect of the first embodiment]
According to the present embodiment, even when the communication speed between the transmission apparatus and the relay apparatus is slower than the communication speed between the relay apparatus and the reception apparatus, the transmission apparatus and the reception apparatus It is possible to sufficiently reduce the power consumption of the receiving device while maintaining the communication time when direct communication is performed. The reason is that the receiving device is configured to transition from the normal state to the power saving state when a session with the transmitting device is established, and the relay device is configured to transfer the data stored in the buffer. Calculate the transfer start timing that can match the timing at which data transfer from the transmission device to the relay device (buffer) ends with the timing at which data transfer from the relay device to the reception device ends. This is because the receiving apparatus is shifted from the power saving state to the normal state at the transfer start timing, and the transfer of the data stored in the buffer is started.

[Second embodiment of the present invention]
Next, a second embodiment of the relay system according to the present invention will be described. The present embodiment is characterized in that the power consumption of the receiving apparatus is reduced while preventing the occurrence of a situation in which data is discarded due to insufficient capacity of the buffer area.

  The relay system according to the present embodiment is different from the relay system 100 of the first embodiment in that the relay apparatus 300a shown in FIG. Further, the relay device 300a includes a schedule unit 312a instead of the schedule unit 312, a point including a state control unit 313a instead of the state control unit 313, and data transfer instead of the data transfer unit 314. It differs from the relay device 300 of the first embodiment in that the means 314 is provided.

  The schedule unit 312a has the following functions in addition to the functions of the schedule unit 312.

A function of comparing the total value Bht of the buffer amount (necessary buffer amount) required by each established session with the total capacity Bt of the buffer area 321. The necessary buffer amount for session #i may be written as Bi, h.
When the total value Bht of the necessary buffer amount Bi, h is larger than the total capacity Bt of the buffer area 321, the total capacity Bt of the buffer area 321 is distributed per session when it is equally distributed to the currently established sessions. A function for obtaining a distribution amount (uniform distribution amount) Bd.
A function for comparing the amount of data stored in the buffer of the session with the equally distributed amount Bd for each established session. Note that the data amount accumulated in the buffer for session #i may be denoted as Bi.
A function of notifying the state control means 313a and the data transfer means 314a of the session ID of a session whose data amount Bi is equal to or greater than the uniform distribution amount Bd.
A function for comparing the required buffer amount Bi, h of the session in which the data amount Bi is equal to or less than the equal distribution amount Bd and the equal distribution amount Bd.
A function for updating the transfer start timing and transmission timing recorded in the schedule storage unit 322 for a session in which the required buffer amount Bi, h is equal to or greater than the equal distribution amount Bd.

  In addition to the functions provided in the state control unit 313, the state control unit 313a has a function of immediately transmitting a state transition instruction to the receiving device of the corresponding session when the session ID is notified from the scheduling unit 312a.

  In addition to the functions of the data transfer unit 314, the data transfer unit 314a waits for the receiving device of the corresponding session to transition from the power saving state to the normal state when the session ID is notified from the schedule unit 312a. It has a function of starting data transfer to the receiving device (waiting for the transition time C to elapse).

  The relay device 300a can be realized by a computer, and when realized by a computer, for example, the following is performed. A disk, a semiconductor memory, and other recording media on which a program for causing the computer to function as the data storage unit 311, the schedule unit 312a, the state control unit 313a, and the data transfer unit 314a are prepared, and the computer reads the program. Make it. The computer realizes the above-mentioned means 311, 312 a, 313 a, and 314 a on its own computer by controlling its own operation according to the read program.

[Operation of Second Embodiment]
Next, the operation of the present embodiment will be described.

  Assuming that a new session #n is established between the transmission device 200 and the reception device (for example, the reception device 400) via the relay device 300, the data storage unit 311 includes the first embodiment described above. The same processing is performed. It is assumed that (n-1) sessions of sessions # 1 to # (n-1) have already been established when new session #n is established.

  Further, when the new session #n is established, the scheduling unit 312a first performs the same processing as steps S61 to S66 in FIG. 6 as shown in the flowchart in FIG. 11 (step S1101).

  Thereafter, the scheduling means 312a calculates the necessary buffer Bi, h required for the session #i (1 ≦ i ≦ n) for each session # 1 to #n established at the present time. Specifically, the necessary buffer amount Bi, h of session #i is calculated by performing the calculation shown in the following equation (8) (step S1102).

    Bi, h = Wi, s × (Ti, s−Ti, d) (8)

  Next, the schedule means 312a calculates the total value Bht of the necessary buffer amount by performing the calculation shown in the following equation (9) (step S1103).

  Bht = B1, h + B2, h + ... + Bn, h (9)

  Thereafter, the scheduling unit 312a compares the total value Bht of the necessary buffer amount with the total capacity Bt of the buffer area 321 (step S1105).

  Then, when the total value Bht of the necessary buffer amount is equal to or less than the total capacity Bt of the buffer area 321 (Yes in step S1105), the schedule unit 312a ends the process.

  On the other hand, when the total value Bht of the necessary buffer amount exceeds the total capacity Bt of the buffer area 321 (No in step S1105), the schedule unit 312a performs the calculation shown in the following equation (10). Then, a distribution amount (equal distribution amount) Bd per session when the buffer area 321 is evenly distributed to the currently established sessions is calculated (step S1106).

  Bd = Bt ÷ (number of established sessions n) (10)

  Thereafter, the scheduling means 312a pays attention to one of the unfocused sessions (for example, session #i) (step S1107), and data transfer from the relay apparatus 300 to the receiving apparatus is started in the session #i. Is determined (step S1201 in FIG. 12).

  If data transfer from the transmission apparatus 200 to the reception apparatus has been started (Yes in step S1201), the process returns to step S1107 in FIG. 11 and focuses on one of the unfocused sessions.

  On the other hand, if the data transfer from the relay apparatus 300 to the receiving apparatus is not started in the session #i that is being noticed (No in step S1201), the session is distributed evenly and the session #i that is being noticed. The amount of data Bi actually stored in the buffer is compared (step S1202).

  Then, as shown in FIG. 13A, when the data amount Bi accumulated in the buffer for session #i exceeds the equal distribution amount Bd (Yes in step S1203), the scheduling unit 312a The session control unit 313a and the data transfer unit 314a are notified of the session ID “#i” of the session #i of interest (step S1204).

  Upon receiving this notification, the state control unit 313a immediately transmits a state transition instruction to the receiving device of session #i, and causes the receiving device to transition from the power saving state to the normal state. In addition, the data transmission unit 314a receives the transition time C (the time required for the receiving device of the session #i to transition from the power saving state to the normal state) after the session ID “#i” is notified. Then, data transfer to the receiving device is started. That is, as shown in FIG. 13A, for a session in which the data amount Bi accumulated in the buffer is equal to or greater than the equal distribution amount Bd, the state of the receiving device of the session is immediately changed to the normal state, and data transfer is performed. To start.

  On the other hand, when the data amount Bi accumulated in the buffer for session #i is equal to or less than the equal distribution amount Bd (step S1203), the necessary buffer amount Bi, h and the equal distribution amount Bd for session #i. Are compared (step S1205).

  As shown in FIG. 13B, when the required buffer amount Bi.h of the session #i exceeds the equal distribution amount Bd (Yes in step S1206), the transfer start timing ti, a, Then, the transmission timing ti, b is updated (step S1207). Specifically, the transfer start timing ti, a and the transmission timing ti, b of the session #i are updated as follows.

  First, the transfer start timing ti, a for session #i is calculated by performing the calculation shown in the following equation (11). In Equation (11), Si, s is the amount of data that has been transferred by the transmitting device via session #i.

  ti, a = current time + (Bd-Si, s) / Wi, s (11)

  Thereafter, the transfer start timing for session #i recorded in the schedule storage unit 322 is replaced with the transfer start timing ti, a obtained by the equation (11). That is, the data transfer start timing is replaced with the time at which data for the equal distribution amount Bd is accumulated in the buffer of session #i.

  Next, the transmission timing ti, b for session #i is calculated by performing the calculation shown in the following equation (12). In Expression (12), Ci represents a transition time required until the receiver of session #i transitions from the power saving state to the normal state.

  ti, b = ti, a-Ci (12)

  Thereafter, the transmission timing for session #i recorded in the schedule storage unit 322 is replaced with the transmission timing ti, b obtained by the equation (12). The above is the details of the process performed in step S1207.

  When the processing in step S1207 is completed, the scheduling unit 312a pays attention to the next session (step S1106 in FIG. 11).

  On the other hand, as shown in FIG. 13C, when the necessary buffer amount Bi, h of the session #i is less than the equal buffer amount Bd (No in step S1206), the scheduling unit 312a proceeds to the next session. Pay attention (1106 in FIG. 11).

  The scheduling unit 312a repeats the above processing until there is no unfocused session, and when there is no unprocessed session (Yes in step S1108), the processing ends.

[Effect of the second embodiment]
According to the present embodiment, in addition to the effect obtained in the first embodiment, it is possible to prevent the occurrence of a situation in which data is discarded due to insufficient capacity of the buffer area as much as possible. Can do. The reason is that if the total required buffer size required by each session via the relay device exceeds the capacity of the buffer area, the amount of data stored in the buffer exceeds the even distribution amount. This is because the data transfer from the session buffer to the receiving device is started immediately.

  The present invention is used in a relay apparatus that relays data transmitted from a transmission apparatus to a reception apparatus, a capacity for temporarily holding data received from the transmission apparatus, and a buffer storage transfer control method that controls the transfer schedule. Is possible.

100 relay system 200 transmission device 300 relay device 310 control unit 311 data storage unit 312, 312a schedule unit 313, 313a state control unit 314, 314a data transfer unit 320 storage device 321 buffer area 322 schedule storage unit 330 communication unit 400 reception unit 410 Communication unit 420 Control unit 421 Download unit 422 State switching unit 423 State transition instruction detection unit 430 Input unit 440 Output unit 500 Communication network

Claims (10)

For each session that passes through the own relay device, when a session is established with the transmission device, triggered by a data acquisition request made to the transmission device, data transmission / reception is performed. The data transferred from the transmitting device is generated in the buffer area for the receiving device that makes a transition from the possible normal state to the power saving state in which data transmission / reception is impossible and power consumption is lower than the normal state. Data storage means for storing in the session buffer;
Schedule means for calculating a transfer start timing, which is a timing at which preparation for transferring data stored in the buffer for the session is completed for each session passing through the own relay device;
For each session that passes through the own relay device, at the transfer start timing calculated by the scheduling unit for the session, a state control unit that transitions the state of the receiving device of the session from the power saving state to the normal state;
A data transfer unit that starts data transfer from the buffer for the session to the receiving device of the session at the transfer start timing calculated by the schedule unit for each session passing through the own relay device; A relay apparatus comprising: The relay device according to claim 1,
For each session that passes through the relay device, the scheduling means finishes the data transfer from the session transmission device to the session buffer and the data from the session buffer to the session reception device. A relay apparatus that calculates a transfer start timing that can match a transfer end timing. The relay device according to claim 1 or 2,
The scheduling means calculates a transfer start timing for each session via the own relay device every time a new session via the own relay device is established,
For each session that passes through the relay device, the state control unit changes the state of the reception device of the session from the power saving state to the normal state at the latest transfer start timing calculated by the scheduling unit for the session. Transition to
The data transfer means, for each session passing through the own relay device, at the latest transfer start timing calculated by the schedule means for the session, data from the session buffer to the session receiving device A relay device that starts transfer. The relay device according to claim 1, 2, or 3,
For each session passing through the own relay device, the scheduling means includes a transmission side communication speed on the transmission device side relative to the own relay device, a reception side communication speed on the reception device side relative to the own relay device, and a size of data to be transferred. Based on the above, the reception time from the start of reception of the data by the own relay device to the end of reception of the data, and the end of the data transfer after the own relay device starts the transfer of the data A relay device that calculates a transfer time until the transfer is started and calculates a transfer start timing based on a difference between the calculated reception time and the transfer time. The relay device according to any one of claims 1 to 4,
The scheduling means compares the total buffer amount required for each session via the own relay device with the capacity of the buffer area each time a new session via the own relay device is established, When the total value exceeds the capacity of the buffer area, for each session that has not started data transfer from the buffer to the receiving device, the amount of data stored in the buffer for the session is less than the buffer area. Determine whether or not the distribution amount per session when the distribution is evenly distributed to the sessions via the relay device,
The state control unit changes the state of the reception device of the session from the power saving state to the normal state for the session in which the amount of data stored in the buffer is determined to exceed the distribution amount in the scheduling unit. Transition
The data transfer means starts the data transfer from the buffer for the session to the receiving apparatus for the session in which the amount of data stored in the buffer is determined to exceed the distribution amount in the scheduling means. A relay device characterized by that. The relay device according to claim 5,
For the session for which it is determined that the data amount stored in the buffer is less than or equal to the distribution amount, the scheduling means compares the necessary buffer amount required for the session with the distribution amount, and the necessary buffer amount is the distribution amount. For a session exceeding the amount, the transfer start timing of the session is changed to a timing at which the data for the distribution amount is stored in the buffer of the session.   When a session via the relay device is established with the transmission device triggered by a data acquisition request made from the reception device to the transmission device, the normal state in which the state of the reception device can transmit and receive data When receiving a state transition instruction sent from the relay device, the state of the own receiving device is changed from the power saving state to the normal state. A receiving apparatus comprising state switching means for transitioning to a state. A relay system for transferring data from a transmission device to a reception device via a relay device,
The relay device is
For each session passing through the own relay device, data storage means for storing data transferred from the session transmission device to the session reception device in a buffer for the session;
Schedule means for calculating a transfer start timing, which is a timing at which preparation for transferring data stored in the buffer for the session is completed for each session passing through the own relay device;
A data transfer unit that starts data transfer from the buffer for the session to the receiving device of the session at the transfer start timing calculated by the schedule unit for each session passing through the own relay device; With
The receiving device is:
When a session is established with the transmission device triggered by a data acquisition request made to the transmission device, the state of the own reception device cannot be transmitted / received from a normal state where data transmission / reception is possible. It is provided with state switching means for making a transition to a power saving state in which power consumption is less than a normal state, and for making a transition from the power saving state to the normal state at the transfer start timing calculated by the scheduling means. A relay system. When the data storage means is a receiving device of the session for each session passing through the own relay device, and a session is established with the transmitting device triggered by a data acquisition request made to the transmitting device The data transferred from the transmitting device to the receiving device that transitions from the normal state in which data can be transmitted / received to the power saving state in which data transmission / reception is impossible and power consumption is lower than the normal state is stored in the buffer area. Accumulates in the session buffer generated above,
For each session that passes through the relay device, the scheduling means calculates the transfer start timing, which is the timing when the data stored in the session buffer is ready for transfer,
For each session that passes through the own relay device, the state control unit causes the receiving device state of the session to transition from the power saving state to the normal state at the transfer start timing calculated for the session by the scheduling unit. ,
The data transfer means starts data transfer from the session buffer to the receiving apparatus of the session at the transfer start timing calculated for the session by the scheduling means for each session passing through the own relay apparatus. A relay method characterized by: Computer
For each session that passes through the relay device, when the session is established with the transmission device, triggered by a data acquisition request made to the transmission device, data can be transmitted and received The data transferred from the transmitting device is generated in the buffer area for the receiving device that is incapable of transmitting and receiving data from the normal state and transitions to the power saving state that consumes less power than the normal state. Data storage means for storing in the session buffer,
Schedule means for calculating a transfer start timing, which is a timing at which preparation for transferring data stored in the buffer for the session is completed for each session passing through the relay device;
For each session passing through the relay device, at the transfer start timing calculated by the scheduling unit for the session, a state control unit that transitions the state of the receiving device of the session from the power saving state to the normal state;
As data transfer means for starting data transfer from the session buffer to the receiving apparatus of the session at the transfer start timing calculated by the schedule means for the session for each session passing through the relay device A program to make it work.

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