Communication device and communication control method

Abstract

This communication device comprises: a communication unit that performs transmission / reception of signals with another communication device; and a control unit that switches the communication unit from a suspension state to an operating state by the reception timing of the signals, causes the communication unit to transmit the signals when the communication unit is in the operating state, and switches the communication unit from the operating state to the suspension state after the transmission / reception of the signals is performed.

Description

[Technical field]

[0001] The present invention relates to a communication device and a communication control method. [Background technology]

[0002] Nowadays, a wide variety of things are being connected to the Internet. The things referred to here are devices (hereinafter referred to as "terminal devices". The terminal devices are an example of communication devices) equipped with a communication function unit. In an IoT (Internet of Things) system (see, for example, FIG. 8), which is a service form in which such terminal devices transmit and receive information, the terminal devices and devices (e.g., sensors serving as information sources) connected to the terminal devices may be installed in places where it is difficult to secure commercial power, such as in the mountains. On the other hand, devices that communicate with the terminal devices (hereinafter referred to as "terminal devices". The terminal devices are an example of communication devices) are mainly installed within the premises of data centers or base stations, and therefore it is relatively easy to secure commercial power in many cases. For example, the following two methods can be considered as methods for stably operating the terminal devices in such a communication environment.

[0003] The first method is to secure an alternative power source to replace the commercial power source. For example, a method of using a primary battery to supply power to a terminal device can be considered. However, in this case, if the primary battery is discharged, power cannot be supplied to the terminal device until it is replaced with a new primary battery. Another method of using energy harvesting, such as a solar cell, to supply power to a terminal device can be considered. However, with energy harvesting from a solar cell or the like, the amount of power supplied decreases on cloudy days.

[0004] The second method is to reduce the power consumption of the terminal device. If the power consumption of the terminal device can be reduced, for example, the period until a primary battery is discharged can be extended, and the terminal device can continue to operate stably. In addition, if the power consumption of the terminal device can be reduced, the terminal device can be operated even in a situation where the power supply of the energy harvesting is low, such as on a cloudy day, and the terminal device can continue to operate stably.

[0005] For example, Non-Patent Documents 1 and 2 disclose a technology for reducing power consumption when a terminal device receives a signal. This technology reduces power consumption by putting some or all of the functions of the terminal device into an operating state when receiving a signal and into a dormant state at other times. Note that the power consumption of the terminal device is high when it is in an operating state and low when it is in a dormant state. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Masashi Tadokoro et al., "Power Saving Technology for Network Equipment and Its Applications - ONU and Wireless LAN Sleep Technology," NTT Technical Journal, pp.28-32, January 2014. [Non-Patent Document 2] Hirotaka Ujikawa et al., "Efforts to reduce power consumption in optical access communication equipment," NTT Technical Journal, pp.32-35, January 2015. Summary of the Invention [Problem to be solved by the invention]

[0007] Generally, when a terminal device transitions from a sleep state to an active state, it passes through an active state on the way. The active state here is a preparation period for changing the state of the terminal device from a state in which it is not possible to transmit or receive signals to a state in which it is. While the terminal device is in the active state, it consumes high power even though it is not possible to transmit or receive signals.

[0008] In addition, one cycle of signal transmission and reception generally includes a wake-up state associated with the start-up of the terminal device when transmitting a signal, and a wake-up state associated with the start-up of the terminal device when receiving a signal. Therefore, in the past, when the frequency of the terminal device transitioning from the sleep state to the operating state is particularly high, the frequency of the terminal device being in the wake-up state also increases, which has been a problem in that the effect of reducing the power consumption of the terminal device by providing a sleep state is hindered.

[0009] The present invention has been made in consideration of the above-described technical background, and aims to provide a communication device and a communication control method that can achieve even lower power consumption in a communication device that aims to reduce power consumption by providing a hibernation state. [Means for solving the problem]

[0010] Also, one aspect of the present invention is a communication device comprising a communication unit that transmits and receives signals with other communication devices, and a control unit that switches the communication unit from a dormant state to an operating state by the timing of receiving the signal, causes the communication unit to transmit the signal while the communication unit is in the operating state, and switches the communication unit from the operating state to the dormant state after the signal is transmitted and received.

[0011] Also, one aspect of the present invention is a communication device comprising a communication unit that transmits and receives signals with other communication devices, and a control unit that causes the communication unit to transmit the signal at a transmission timing determined so that the reception timing of the signal in the other communication device is a timing when the other communication device is in a state in which it is able to receive the signal.

[0012] Another aspect of the present invention is a communication control method having a communication step of transmitting and receiving a signal with another communication device, and a control step of switching the device from a dormant state to an operating state by the timing of receiving the signal, causing the device to transmit the signal while the device is in the operating state, and switching the device from the operating state to the dormant state after the signal is transmitted and received.

[0013] Another aspect of the present invention is a communication control method having a communication step of transmitting and receiving a signal with another communication device, and a control step of causing the device to transmit the signal at a transmission timing determined so that the reception timing of the signal at the other communication device is a timing when the other communication device is in a state where it can receive the signal. Effect of the Invention

[0014] According to the present invention, in a communication device which aims to reduce power consumption by providing a sleep state, it is possible to achieve further reduction in power consumption. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram showing a connection configuration between a terminal device 1 and a termination device 2 in a communication system according to a first embodiment of the present invention. [Diagram 2] 1 is a block diagram showing a configuration of a terminal device 1 according to a first embodiment of the present invention. [Diagram 3] 1 is a block diagram showing a configuration of a termination device 2 according to a first embodiment of the present invention. [Figure 4] 1 is a diagram showing the operation of a terminal device 1 and a terminating device 2 and the state of the terminal device 1 according to the first embodiment of the invention. [Diagram 5] FIG. 1 is a diagram illustrating the operation of a terminal device and a terminating device and the state of the terminal device in the prior art. [Figure 6] 11 is a diagram illustrating operations of a terminal device 1 and a termination device 2 and a state of the terminal device 1 according to the second embodiment of the present invention. FIG. [Figure 7]13 is a diagram illustrating operations of a terminal device 1 and a termination device 2 and a state of the terminal device 1 according to the third embodiment of the present invention. FIG. [Figure 8] FIG. 1 is a diagram illustrating an example of a configuration of a typical IoT system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described. In each of the embodiments described below, a communication control method in an IoT (Internet of Things) terminal will be described as an example, but the present invention is not limited thereto. For example, the communication control method of the present invention can be applied to various communication devices, such as an ONU (Optical Network Unit) of a PON (Passive Optical Network) system. In each of the embodiments described below, the communication form is the Internet as an example, but the present invention is not limited thereto. For example, the communication control method of the present invention can be applied to various other communication forms, such as communication by Ethernet and a PON system.

[0017] <First embodiment> Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

[0018] [Connection between terminal device and terminating device] Hereinafter, a connection form between the terminal device and the termination device in the communication system according to the present embodiment will be described. Figures 1(A) to (C) are diagrams showing a connection form between a terminal device 1 and a termination device 2 in the communication system according to the first embodiment of the present invention.

[0019] 1(A) to (C), the communication system according to this embodiment is a communication system in which a terminal device 1 and a termination device 2 are connected by a transmission path 3 and can communicate with each other via the transmission path 3. Each of Figs. 1(A) to (C) shows an example of a connection form between the terminal device 1 and the termination device 2, and the communication control method of the present invention can be applied to any of the connection forms.

[0020] For example, as shown in Fig. 1(A), the connection between the terminal device 1 and the termination device 2 may be a connection in which only one terminal device 1 is connected to one termination device 2. Alternatively, as shown in Fig. 1(B), the connection between the terminal device 1 and the termination device 2 may be a connection in which a switch 4 is provided in the middle of the transmission path 3, and multiple terminal devices 1 are connected to one termination device 2. Alternatively, as shown in Fig. 1(C), the connection between the terminal device 1 and the termination device 2 may be a connection in which an optical splitter 5 is provided in the middle of the transmission path 3, and multiple terminal devices 1 are connected to one termination device 2.

[0021] In the following description, the one-way signal propagation time between the terminal device 1 and the termination device 2 is defined as Δt access It is expressed as Δt access The value of can be calculated, for example, by dividing the time required for a signal to travel round trip between terminal device 1 and termination device 2 by 2.

[0022] [Terminal device configuration] The configuration of the terminal device 1 according to this embodiment will be described below. Figures 2(A) and (B) are block diagrams showing the configuration of the terminal device 1 according to the first embodiment of the present invention. Figures 2(A) and (B) are diagrams showing examples of the configuration of the terminal device 1, respectively, and the communication control method of the present invention can be applied to terminal devices 1 of either configuration.

[0023] 2(A) and (B), the terminal device 1 includes a network interface unit 11, a buffer unit 12, and a communication control unit 14. The network interface unit 11 is connected to a termination device 2 via a transmission path 3. The buffer unit 12 temporarily stores signals. The communication control unit 14 controls the operation / pause switching of each unit of the terminal device 1, and controls the transmission of signals.

[0024] When the communication control unit 14 of the terminal device 1 transmits and receives information to and from the communication control unit 24 of the termination device 2 by using a communication control signal, as shown in Figures 2(A) and (B), the terminal device 1 includes a signal superimposing / separating unit 13. The signal superimposing / separating unit 13 superimposes the communication control signal on the main signal. The signal superimposing / separating unit 13 also separates the communication control signal from the main signal.

[0025] 2(A), if necessary, the terminal device 1 may further include a user equipment interface unit 15. The user equipment interface unit 15 is a communication interface for transferring a main signal to a user equipment.

[0026] 2(B), the terminal device 1 may further include an operation / measurement unit 16, as necessary. The operation / measurement unit 16 performs display and operation based on the main signal received by the terminal device 1. The operation / measurement unit 16 also includes the result of measurement by, for example, a sensor (not shown) on the main signal transmitted from the terminal device 1.

[0027] If necessary, the terminal device 1 may include both the user device interface unit 15 and the operation / measurement unit 16.

[0028] The communication control unit 14 instructs, by an operation / pause switching control signal, to operate or pause at least one of the functional units other than the communication control unit 14 included in the terminal device 1. The functional units other than the communication control unit 14 referred to here are the network interface unit 11, the buffer unit 12, the signal superposition / separation unit 13, the user equipment interface unit 15, the operation / measurement unit 16, and other functional units not shown.

[0029] In addition, when a functional unit is instructed to pause and enters a paused state, it stops or reduces the power supply to components involved in signal transmission, thereby reducing the power consumption of the entire terminal device 1. In addition, the components involved in signal transmission here include, for example, an internal light source, a photodiode, an amplifier, a signal read circuit, a signal write circuit, and an arithmetic circuit.

[0030] It should be noted that even in the pause state, the buffer unit 12 needs to hold the stored information (for example, main signals and communication control signals, etc.) without erasing it. For this reason, for example, the memory that stores the information may be configured so that power is always supplied to it, or a non-volatile memory that can hold information even when power is not supplied may be used.

[0031] Moreover, the communication control unit 14 instructs the buffer unit 12 to transmit an upstream signal by a transmission instruction signal. The upstream signal here is a signal going from the terminal device 1 to the termination device 2, and is a main signal and a communication control signal superimposed on the main signal.

[0032] Furthermore, the communication control unit 14 communicates with the communication control unit 24 of the termination device 2 using a communication control signal to transmit and receive information indicating a time period during which the termination device 2 may transmit a downstream signal (to the terminal device 1). As a result, the information indicating the time period during which the termination device 2 may transmit a downstream signal is shared between the terminal device 1 and the termination device 2.

[0033] [End device configuration] The configuration of the termination device 2 according to this embodiment will be described below. Figures 3(A) and (B) are block diagrams showing the configuration of the termination device 2 according to the first embodiment of the present invention. Figures 3(A) and (B) are diagrams showing examples of the configuration of the termination device 2, respectively, and the communication control method of the present invention can be applied to termination devices 2 of either configuration.

[0034] 3(A) and (B), the termination device 2 includes a network interface unit 21, a buffer unit 22, and a communication control unit 24. The network interface unit 21 is connected to the terminal device 1 via the transmission path 3. The buffer unit 22 temporarily stores signals. The communication control unit 24 controls the transmission of signals.

[0035] When the communication control unit 24 of the terminating device 2 transmits and receives information to and from the communication control unit 14 of the terminal device 1 by a communication control signal, as shown in Figures 3(A) and (B), the terminating device 2 includes a signal superimposing / separating unit 23. The signal superimposing / separating unit 23 superimposes the communication control signal on the main signal. The signal superimposing / separating unit 23 also separates the communication control signal from the main signal.

[0036] 3A, if necessary, the terminating device 2 may further include a host device interface unit 25. The host device interface unit 25 is a communication interface for transferring the main signal to a host device.

[0037] 3B, the termination device 2 may further include a calculation unit 26, if necessary. The calculation unit 26 performs display and signal processing based on the main signal received by the termination device 2. The calculation unit 26 also includes instructions for the terminal device 1 in the main signal transmitted from the termination device 2.

[0038] If necessary, the terminating device 2 may include both the host device interface unit 25 and the calculation unit 26.

[0039] The communication control unit 24 instructs the buffer unit 22 to transmit a downstream signal by using a transmission instruction signal. The downstream signal here is a signal going from the termination device 2 to the terminal device 1, and is a main signal and a communication control signal superimposed on the main signal.

[0040] Furthermore, the communication control unit 24 transmits and receives information indicating a time period during which the termination device 2 may transmit a downstream signal (to the terminal device 1) by communicating with the communication control unit 14 of the terminal device 1 using a communication control signal. As a result, the information indicating the time period during which the termination device 2 may transmit a downstream signal is shared between the termination device 2 and the terminal device 1.

[0041] The information indicating the time period during which the termination device 2 may transmit a downstream signal may be generated by the termination device 2 or the like, and may be shared by being transmitted from the termination device 2 to the terminal device 1. Alternatively, the information indicating the time period during which the termination device 2 may transmit a downstream signal may be generated by the terminal device 1 or the like, and may be shared by being transmitted from the terminal device 1 to the termination device 2.

[0042] [Operation of terminal device and terminating device] Hereinafter, a description will be given of the operations of the terminal device 1 and the terminating device 2 according to this embodiment. Fig. 4 is a diagram showing the operations of the terminal device 1 and the terminating device 2 and the state of the terminal device 1 according to the first embodiment of the present invention.

[0043] In this embodiment, the state of the terminal device 1 transitions in one transmission / reception cycle in the following order: wake-up state, operating state (state capable of receiving downlink signals), operating state (state capable of transmitting uplink signals), and dormant state.

[0044] Here, each symbol is defined as follows. Δt access : The one-way signal propagation time between terminal device 1 and termination device 2. Δt wakeup : The startup time of the terminal device 1 (the time it has been in an active state). Δt d_N : The time during which the terminal device 1 is in an operating state (a state capable of receiving a downstream signal) in the Nth transmission / reception cycle. Δt u_N : The time during which the terminal device 1 is in an operating state (a state capable of transmitting an upstream signal) in the Nth transmission / reception cycle. T wakeup_N : The start time of the startup state in the terminal device 1 in the Nth transmission / reception cycle.

[0045] Of the above signs, Δt access and Δt wakeup The values ​​of Δt are determined based on the characteristics of the transmission line 3 and the terminal device 1. d_N , Δt u_N , and T wakeup_NThe value of is a value whose optimal value can vary depending on the remaining power of the primary battery of the terminal device 1, and generally depends on the value of the number N of transmission and reception cycles.

[0046] Generally, when the remaining power of a primary battery becomes low, Δt d_N and Δt u_N Decrease the value of or T wakeup_N However, in the present invention, these values ​​are not prescribed and are arbitrary.

[0047] At this time, in the Nth transmission / reception cycle, the terminal device 1 wakeup_N At time T wakeup_N +Δt wakeup At time T wakeup_N +Δt wakeup +Δt d_N At time T wakeup_N +Δt wakeup +Δt d_N +Δt u_N The timing of the transition of the state of the terminal device 1 can be expressed by a mathematical formula, such as transitioning to the hibernation state immediately after the start of the process.

[0048] The state transition control in the terminal device 1 is performed based on an instruction to operate or pause from the communication control unit 14 of the terminal device 1. The communication control unit 14 wakeup_N The communication control unit 14 issues an instruction to operate the functional unit, and the functional unit that receives the instruction transitions from a dormant state to a running state and then to an operating state. wakeup_N +Δt wakeup +Δt d_N +Δt u_N The functional unit that receives the instruction transitions from an active state to a suspended state.

[0049] The terminal device 1 receives the downstream signal when the terminal device 1 is in an operating state (a state in which the terminal device 1 can receive the downstream signal). In this case, the operating conditions of the terminal device 1 and the terminating device 2 can be expressed as the following formula (1) using the symbols defined as follows:

[0050] T onu_r_start_N : The time when the downstream signal starts to be received at the terminal device 1 in the Nth transmission / reception cycle. T onu_r_stop_N : The end time of reception of the downstream signal at the terminal device 1 in the Nth transmission / reception cycle. T olt_t_start_N : The start time of downstream signal transmission at the end device 2 in the Nth transmission / reception cycle. T olt_t_stop_N : The end time of downstream signal transmission at the end device 2 in the Nth transmission / reception cycle.

[0051] T wakeup_N +Δt wakeup ≦T onu_r_start_N <T onu_r_stop_N ≦T wakeup_N +Δt wakeup +Δt d_N (1)

[0052] Here, T olt_t_start_N and T olt_t_stop_N can be expressed as the following equations (2) and (3), so the above equation (1) can be expressed as the following equation (4).

[0053] T olt_t_start_N =T onu_r_start_N -Δt access (2)

[0054] T olt_t_stop_N =T onu_r_stop_N -Δt access (3)

[0055] T wakeup_N +Δt wakeup -Δt access ≦T olt_t_start_N <T olt_t_stop_N ≦Twakeup_N +Δt wakeup +Δt d_N -Δt access (4)

[0056] That is, the end device 2 transmits the downstream signal in the Nth transmission / reception cycle at the transmission start time T wakeup_N +Δt wakeup -Δt access After that, and transmission end time Tw akeup_N +Δt wakeup +Δt d_N -Δt access It is sufficient to perform transmission control so that the transmission is performed at a time earlier than the time when the terminal device 1 is in an operating state (a state in which the terminal device 1 can receive a downlink signal).

[0057] The control of the start and end of transmission of the downstream signal in the terminating device 2 is performed by the communication control unit 24 controlling the buffer unit 22. The buffer unit 22 is controlled so as to output the downstream signal only between the transmission start time and the transmission end time, and to store the transmission data during the other times.

[0058] The transmission of an upstream signal by the terminal device 1 is performed when the terminal device 1 is in an operating state (a state in which an upstream signal can be transmitted). In this case, the operating conditions of the terminal device 1 and the terminating device 2 can be expressed as in the following formula (5) using the symbols defined as follows.

[0059] T onu_t_start_N :The start time of transmission of the upstream signal in the terminal device 1 in the Nth transmission / reception cycle. T onu_t_stop_N :The end time of transmission of the upstream signal in the terminal device 1 in the Nth transmission / reception cycle. T olt_r_start_N : The time when the upstream signal starts to be received at the end device 2 during the Nth transmission / reception cycle. T olt_r_stop_N : The time when the upstream signal is received at the end device 2 during the Nth transmission / reception cycle.

[0060] T wakeup_N +Δt wakeup +Δt d_N ≦T onu_t_start_N <T onu_t_stop_N ≦T wakeup_N +Δt wakeup +Δt d_N +Δt u_N (5)

[0061] Here, T olt_r_start_N and T olt_r_stop_N can be expressed as the following equations (6) and (7), so the above equation (5) can be expressed as the following equation (8).

[0062] T olt_r_start_N =T onu_t_start_N +Δt access (6)

[0063] T olt_r_stop_N =T onu_t_stop_N +Δt access (7)

[0064] T wakeup_N +Δt wakeup +Δt d_N +Δt access ≦T olt_r_start_N <T olt_r_stop_N ≦T wakeup_N +Δt wakeup +Δt d_N +Δt u_N +Δt access (8)

[0065] That is, the terminal device 1 transmits an uplink signal in the Nth transmission / reception cycle at a transmission start time T wakeup_N +Δt wakeup +Δt d_N After that, and transmission end time T wakeup_N +Δt wakeup +Δt d_N +Δt u_NIt is sufficient to perform transmission control so that the upstream signal is transmitted at the previous time. As a result, when the terminal device 1 is in an operating state (a state in which the upstream signal can be transmitted), the upstream signal is transmitted from the terminal device 1.

[0066] The control of the start and end of transmission of the uplink signal in the terminal device 1 is performed by the communication control unit 14 controlling the buffer unit 12. The buffer unit 12 is controlled so as to output the uplink signal only between the transmission start time and the transmission end time, and to store the transmission data during the other times.

[0067] In Fig. 4, the column marked with (*1) reads "possible", but if the terminal device 1 is configured to suspend the transmission function of the upstream signal, this column reads "not possible". In Fig. 4, the column marked with (*2) reads "possible", but if the terminal device 1 is configured to suspend the transmission function of the downstream signal, this column reads "not possible".

[0068] 4, the state of the terminal device 1 in the first embodiment transitions continuously from a wake-up state to an operating state (a state capable of receiving a downlink signal) to an operating state (a state capable of transmitting an uplink signal) in one transmission / reception cycle. Therefore, even though the terminal device 1 receives and transmits signals in one transmission / reception cycle, the state of the terminal device 1 becomes the wake-up state, which consumes high power, only once.

[0069] In contrast, in the case of the conventional technology, where the state of the terminal device does not continuously transition from a wake-up state to an operating state (a state capable of receiving a downstream signal) to an operating state (a state capable of transmitting an upstream signal) in one transmission / reception cycle, the state is as shown in Fig. 5. Fig. 5 is a diagram showing the operation of the terminal device and the terminating device in the conventional technology, and the state of the terminal device. As shown in Fig. 5, in the case of the conventional technology, the state of the terminal device becomes the wake-up state, which consumes high power, twice.

[0070] In Fig. 5, the column marked with (*1) reads "possible", but if the terminal device 1 is configured to suspend the transmission function of the upstream signal, this column reads "not possible". In Fig. 5, the column marked with (*2) reads "possible", but if the terminal device 1 is configured to suspend the transmission function of the downstream signal, this column reads "not possible".

[0071] As described above, the communication system according to the first embodiment has a configuration for successively switching between the operation state (state capable of receiving downlink signals) and the operation state (state capable of transmitting uplink signals) of the terminal device 1, and for receiving downlink signals and transmitting uplink signals in each operation state. By having such a configuration, the communication system according to the first embodiment can reduce the period (number of times) during which the terminal device 1 is in an activated state with high power consumption, thereby realizing low power consumption of the terminal device 1.

[0072] <Second embodiment> Hereinafter, the second embodiment of the present invention will be described with reference to the drawings. Note that the connection form between the terminal device 1 and the termination device 2, the configuration of the terminal device 1, and the configuration of the termination device 2 in the communication system according to the second embodiment are the same as those in the first embodiment, and therefore the description will be omitted.

[0073] [Operation of terminal device and end device] Hereinafter, a description will be given of the operations of the terminal device 1 and the terminating device 2 according to this embodiment. Fig. 6 is a diagram showing the operations of the terminal device 1 and the terminating device 2 and the state of the terminal device 1 according to the second embodiment of the present invention.

[0074] In this embodiment, the state of the terminal device 1 changes in one transmission / reception cycle in the following order: wake-up state, operating state (state capable of receiving uplink signals), operating state (state capable of transmitting downlink signals), and dormant state.

[0075] As mentioned above, Δt access and Δt wakeupThe values ​​of are determined as the characteristics of the transmission line 3 and the terminal device 1, respectively. d_N , Δt u_N , and T wakeup_N The value of is a value whose optimal value can vary depending on the remaining power of the primary battery of the terminal device 1, and generally depends on the value of the number N of transmission and reception cycles.

[0076] Generally, when the remaining power of a primary battery becomes low, Δt d_N and Δt u_N Decrease the value of or T wakeup_N However, in the present invention, these values ​​are not prescribed and are arbitrary.

[0077] At this time, in the Nth transmission / reception cycle, the terminal device 1 wakeup_N At time T wakeup_N +Δt wakeup At time T wakeup_N +Δt wakeup +Δt u_N At time T wakeup_N +Δt wakeup +Δt u_N +Δt d_N The timing of the transition of the state of the terminal device 1 can be expressed by a mathematical formula, such as transitioning to the hibernation state immediately after the start of the process.

[0078] The state transition control in the terminal device 1 is performed based on an instruction to operate or pause from the communication control unit 14 of the terminal device 1. The communication control unit 14 wakeup_N The communication control unit 14 issues an instruction to operate the functional unit, and the functional unit that receives the instruction transitions from a dormant state to a running state and then to an operating state. wakeup_N +Δt wakeup +Δt d_N +Δt u_N The functional unit that receives the instruction transitions from an active state to a suspended state.

[0079] The transmission of an upstream signal by the terminal device 1 is performed when the terminal device 1 is in an operating state (a state in which an upstream signal can be transmitted). In this case, the operating conditions of the terminal device 1 and the terminating device 2 can be expressed as the following formula (9).

[0080] T wakeup_N +Δt wakeup +Δt u_N ≦T onu_t_start_N <T onu_t_stop_N ≦T wakeup_N +Δt wakeup +Δt u_N +Δt d_N (9)

[0081] Here, T olt_r_start_N and T olt_r_stop_N Since it can be expressed as the above equations (6) and (7), the above equation (9) can be expressed as the following equation (10).

[0082] T wakeup_N +Δt wakeup +Δt u_N +Δt access ≦T olt_r_start_N <T olt_r_stop_N ≦T wakeup_N +Δt wakeup +Δt u_N +Δt d_N +Δt access (10)

[0083] That is, the terminal device 1 transmits an uplink signal in the Nth transmission / reception cycle at a transmission start time T wakeup_N +Δt wakeup +Δt u_N After that, and transmission end time T wakeup_N +Δt wakeup +Δt u_N +Δt d_N It is sufficient to perform transmission control so that the upstream signal is transmitted at the previous time. As a result, when the terminal device 1 is in an operating state (a state in which the upstream signal can be transmitted), the upstream signal is transmitted from the terminal device 1.

[0084] The control of the start and end of transmission of the uplink signal in the terminal device 1 is performed by the communication control unit 14 controlling the buffer unit 12. The buffer unit 12 is controlled so as to output the uplink signal only between the transmission start time and the transmission end time, and to store the transmission data during the other times.

[0085] The terminal device 1 receives the downstream signal when the terminal device 1 is in an operating state (a state in which the terminal device 1 can receive the downstream signal). In this case, the operating conditions of the terminal device 1 and the terminating device 2 can be expressed as the following formula (11).

[0086] T wakeup_N +Δt wakeup +Δt u_N ≦T onu_r_start_N <T onu_r_stop_N ≦T wakeup_N +Δt wakeup +Δt u_N +Δt d_N (11)

[0087] Here, T olt_t_start_N and T olt_t_stop_N can be expressed as the above equations (2) and (3), the above equation (11) can be expressed as the following equation (12).

[0088] T wakeup_N +Δt wakeup +Δt u_N -Δt access ≦T olt_t_start_N <T olt_t_stop_N ≦T wakeup_N +Δt wakeup +Δt u_N +Δt d_N -Δt access (12)

[0089] That is, the end device 2 transmits the downstream signal in the Nth transmission / reception cycle at the transmission start time T wakeup_N +Δt wakeup +Δtu_N -Δt access After that, and transmission end time T wakeup_N +Δt wakeup +Δt u_N +Δt d_N -Δt access It is sufficient to perform transmission control so that the transmission is performed at a time earlier than the time when the terminal device 1 is in an operating state (a state in which the terminal device 1 can receive a downlink signal).

[0090] The control of the start and end of transmission of the downstream signal in the terminating device 2 is performed by the communication control unit 24 controlling the buffer unit 22. The buffer unit 22 is controlled so as to output the downstream signal only between the transmission start time and the transmission end time, and to store the transmission data during the other times.

[0091] In Fig. 6, the column marked with (*1) reads "possible", but if the terminal device 1 is configured to suspend the transmission function of the upstream signal, this column reads "not possible". In Fig. 6, the column marked with (*2) reads "possible", but if the terminal device 1 is configured to suspend the transmission function of the downstream signal, this column reads "not possible".

[0092] 6, the state of the terminal device 1 in the second embodiment transitions continuously from a wake-up state to an operating state (a state capable of transmitting an uplink signal) to an operating state (a state capable of receiving a downlink signal) in one transmission / reception cycle. Therefore, even though the terminal device 1 transmits and receives signals in one transmission / reception cycle, the state of the terminal device 1 becomes the wake-up state, which consumes high power, only once.

[0093] In contrast, in the case of conventional technology in which the state of a terminal device does not continuously transition from a wake-up state to an operating state (a state in which an uplink signal can be transmitted) to an operating state (a state in which a downlink signal can be received) in one transmission / reception cycle, as shown in Figure 5 above, the state of the terminal device will enter the wake-up state, which consumes high power, twice.

[0094] As described above, the communication system according to the second embodiment has a configuration for successively switching between the operation state (state capable of transmitting an uplink signal) and the operation state (state capable of receiving a downlink signal) of the terminal device 1, and for transmitting the uplink signal and receiving the downlink signal in each operation state. By having such a configuration, the communication system according to the second embodiment can reduce the period (number of times) during which the terminal device 1 is in a startup state with high power consumption, thereby realizing low power consumption of the terminal device 1.

[0095] <Third embodiment> Hereinafter, the third embodiment of the present invention will be described with reference to the drawings. Note that the connection form between the terminal device 1 and the termination device 2, the configuration of the terminal device 1, and the configuration of the termination device 2 in the communication system according to the third embodiment are the same as those in the first embodiment, and therefore the description will be omitted.

[0096] [Operation of terminal device and end device] Hereinafter, a description will be given of the operations of the terminal device 1 and the terminating device 2 according to this embodiment. Fig. 7 is a diagram showing the operations of the terminal device 1 and the terminating device 2 and the state of the terminal device 1 according to the third embodiment of the present invention.

[0097] In this embodiment, the state of the terminal device 1 transitions in one transmission / reception cycle in the following order: a wake-up state, an operating state (a state capable of receiving downlink signals and transmitting uplink signals), and a dormant state.

[0098] Here, the symbols are defined as follows. Δt d_u_N : The time during which the terminal device 1 is in an operating state (a state in which it can receive a downstream signal and can transmit an upstream signal) in the Nth transmission / reception cycle.

[0099] As mentioned above, Δt access and Δt wakeup The values ​​of are determined as the characteristics of the transmission line 3 and the terminal device 1, respectively. d_u_N and T wakeup_NThe value of is a value whose optimal value can vary depending on the remaining power of the primary battery of the terminal device 1, and generally depends on the value of the number N of transmission and reception cycles.

[0100] Generally, when the remaining power of a primary battery becomes low, Δt d_u_N Decrease the value of or T wakeup_N However, in the present invention, these values ​​are not prescribed and are arbitrary.

[0101] At this time, in the Nth transmission / reception cycle, the terminal device 1 wakeup_N At time T wakeup_N +Δt wakeup At time T wakeup_N +Δt wakeup +Δt d_u_N The timing of the transition of the state of the terminal device 1 can be expressed by a mathematical formula, such as transitioning to the hibernation state immediately after the start of the process.

[0102] The state transition control in the terminal device 1 is performed based on an instruction to operate or pause from the communication control unit 14 of the terminal device 1. The communication control unit 14 wakeup_N The communication control unit 14 issues an instruction to operate the functional unit, and the functional unit that receives the instruction transitions from a dormant state to a running state and then to an operating state. wakeup_N +Δt wakeup +Δt d_u_N The functional unit that receives the instruction transitions from an active state to a suspended state.

[0103] The terminal device 1 receives the downstream signal when the terminal device 1 is in an operating state (a state in which the terminal device 1 can receive the downstream signal and can transmit the upstream signal). In this case, the operating conditions of the terminal device 1 and the termination device 2 can be expressed as the following formula (13).

[0104] T wakeup_N +Δt wakeup ≦T onu_r_start_N <Tonu_r_stop_N ≦T wakeup_N +Δt wakeup +Δt d_u_N (13)

[0105] Here, T olt_t_start_N and T olt_t_stop_N Since it can be expressed as the above equations (2) and (3), the above equation (13) can be expressed as the following equation (14).

[0106] T wakeup_N +Δt wakeup -Δt access ≦T olt_t_start_N <T olt_t_stop_N ≦T wakeup_N +Δt wakeup +Δt d_u_N -Δt access (14)

[0107] That is, the end device 2 transmits the downstream signal in the Nth transmission / reception cycle at the transmission start time T wakeup_N +Δt wakeup -Δt access After that, and transmission end time T wakeup_N +Δt wakeup +Δt d_u_N -Δt access It is sufficient to perform transmission control so that transmission is performed at the previous time. This allows the terminal device 1 to receive the downlink signal when the terminal device 1 is in an operating state (a state in which the terminal device 1 can receive the downlink signal and can transmit the uplink signal).

[0108] The control of the start and end of transmission of the downstream signal in the terminating device 2 is performed by the communication control unit 24 controlling the buffer unit 22. The buffer unit 22 is controlled so as to output the downstream signal only between the transmission start time and the transmission end time, and to store the transmission data during the other times.

[0109] The transmission of an upstream signal by the terminal device 1 is performed when the terminal device 1 is in an operating state (a state in which the terminal device 1 can receive a downstream signal and can transmit an upstream signal). The operating conditions of the terminal device 1 and the termination device 2 in this case can be expressed as the following equation (15).

[0110] T wakeup_N +Δt wakeup ≦T onu_t_start_N <T onu_t_stop_N ≦T wakeup_N +Δt wakeup +Δt d_u_N (15)

[0111] Here, T olt_r_start_N and T olt_r_stop_N Since it can be expressed as the above equations (6) and (7), the above equation (15) can be expressed as the following equation (16).

[0112] T wakeup_N +Δt wakeup +Δt access ≦T olt_r_start_N <T olt_r_stop_N ≦T wakeup_N +Δt wakeup +Δt d_u_N +Δt access (16)

[0113] That is, the terminal device 1 transmits an uplink signal in the Nth transmission / reception cycle at a transmission start time T wakeup_N +Δt wakeup After that, and transmission end time T wakeup_N +Δt wakeup +Δt d_u_N Transmission control may be performed so that transmission occurs at the previous time, whereby when the terminal device 1 is in an operating state (a state in which a downstream signal can be received and an upstream signal can be transmitted), the upstream signal is transmitted in the terminal device 1.

[0114] The control of the start and end of transmission of the upstream signal in the terminal device 1 is performed by the communication control unit 14 controlling the buffer unit 12. The buffer unit 12 is controlled so as to output the upstream signal only between the transmission start time and the transmission end time, and to store the transmission data during the other times.

[0115] 7, the state of the terminal device 1 in the third embodiment transitions from a wake-up state to an operating state (a state in which downlink signals can be received and uplink signals can be transmitted) in one transmission / reception cycle. In this way, since the terminal device 1 transmits and receives signals at the same timing, the state of the terminal device 1 becomes the wake-up state, which consumes high power, only once.

[0116] In contrast, in the case of conventional technology in which the state of a terminal device does not continuously transition from a wake-up state to an operating state (a state in which an uplink signal can be transmitted) to an operating state (a state in which a downlink signal can be received) in one transmission / reception cycle, as shown in Figure 5 above, the state of the terminal device will enter the wake-up state, which consumes high power, twice.

[0117] As described above, the communication system according to the third embodiment includes a configuration for allowing the terminal device 1 to transmit and receive signals when the terminal device 1 is in an operating state (a state in which downlink signals can be received and uplink signals can be transmitted). By including such a configuration, the communication system according to the third embodiment can reduce the period (number of times) during which the terminal device 1 is in an activated state in which power consumption is high, thereby realizing low power consumption of the terminal device 1.

[0118] <Fourth embodiment> The fourth embodiment of the present invention will be described below. It is assumed that the configuration of the communication system according to the fourth embodiment is used in combination with the configuration of the communication system according to any one of the first to third embodiments described above. Since the connection form between the terminal device 1 and the termination device 2, the configuration of the terminal device 1, and the configuration of the termination device 2 in the communication system according to the fourth embodiment are the same as those in the first embodiment described above, the description will be omitted.

[0119] [Operation of terminal device and end device] The following describes the operations of the terminal device 1 and the termination device 2 according to this embodiment. As described in the first to third embodiments above, in this embodiment as well, the period during which the termination device 2 transmits a downstream signal and the operating state of the terminal device 1 must satisfy the relationship expressed by any one of the following equations (17) to (19).

[0120] When combined with the configuration of the first embodiment.

[0121] T wakeup_N +Δt wakeup -Δt access ≦T olt_t_start_N <T olt_t_stop_N ≦T wakeup_N +Δt wakeup +Δt d_N -Δt access (17)

[0122] When combined with the configuration of the second embodiment.

[0123] T wakeup_N +Δt wakeup +Δt u_N -Δt access ≦T olt_t_start_N <T olt_t_stop_N ≦T wakeup_N +Δt wakeup +Δt u_N +Δt d_N -Δt access (18)

[0124] When combined with the configuration of the third embodiment.

[0125] T wakeup_N +Δt wakeup -Δt access ≦T olt_t_start_N <T olt_t_stop_N ≦T wakeup_N +Δt wakeup +Δt d_u_N -Δt access (19)

[0126] It should be noted that the above formula (17) is the same as the above formula (4), the above formula (18) is the same as the above formula (12), and the above formula (19) is the same as the above formula (14).

[0127] Here, T in the above formulas (17) to (19) wakeup_N , Δt d_N , Δt u_N , and Δt d_u_N The value of T is a value whose optimal value can vary depending on the remaining power of the primary battery of the terminal device 1, and generally depends on the value of the number N of transmission and reception cycles. olt_t_start_N , and T olt_t_stop_N The value of is a value whose required value can vary depending on the amount of information to be communicated by the terminating device 2, and generally depends on the value of the number of transmission and reception cycles N. In the present invention, these values ​​are not prescribed and are arbitrary.

[0128] However, in order for the terminal device 1 to receive the downstream signal normally, the relationship expressed by any one of the above equations (17) to (19) must be satisfied between the terminal device 1 and the termination device 2, even if the above values ​​vary depending on the number N of transmission and reception cycles.

[0129] Therefore, in the communication system of this embodiment, the communication control unit 14 of the terminal device 1 and the communication control unit 24 of the termination device 2 share information indicating a time period during which the termination device 2 may transmit a downstream signal in the (N+1)th or later transmission / reception cycle. The timing at which the communication control unit 14 of the terminal device 1 and the communication control unit 24 of the termination device 2 share the information is the Nth transmission / reception cycle.

[0130] The communication control unit 14 of the terminal device 1 and the communication control unit 24 of the terminating device 2 share information by transmitting and receiving signals by superimposing a communication control signal on a main signal.wakeup_N , Δt d_N , Δt u_N , and Δt d_u_N The communication control unit 14 of the terminal device 1 then sends the calculated information to the communication control unit 24 of the terminating device 2. In this case, even if the communication control signal is configured to be transmitted only in the upstream direction, a minimum level of operation is possible.

[0131] As described above, the communication system according to the fourth embodiment includes a configuration in which the communication control unit 14 of the terminal device 1 and the communication control unit 24 of the terminating device 2 share information indicating a time period during which the terminating device 2 may transmit a downlink signal in the (N+1)th transmission / reception cycle. By including such a configuration, the communication system according to the fourth embodiment can easily detect the start time T wakeup_N , and the time during which it is in operation Δt d_N , Δt u_N , and Δt d_u_N Even if the frequency fluctuates for each transmission / reception cycle, it is possible to enable the terminal device 1 to receive the downstream signal normally.

[0132] <Fifth embodiment> Hereinafter, the fifth embodiment of the present invention will be described. It is assumed that the configuration of the communication system according to the fifth embodiment is used in combination with the configuration of the communication system according to any one of the first to third embodiments described above. Since the connection form between the terminal device 1 and the termination device 2, the configuration of the terminal device 1, and the configuration of the termination device 2 in the communication system according to the fifth embodiment are the same as those in the first embodiment described above, the description will be omitted.

[0133] [Operation of terminal device and end device] The operation of the terminal device 1 and the termination device 2 according to this embodiment will be described below. As with the terminal device 1 and the termination device 2 according to the fourth embodiment described above, in this embodiment too, the communication control unit 14 of the terminal device 1 and the communication control unit 24 of the termination device 2 share information indicating a time period during which the termination device 2 may transmit a downstream signal in the (N+1)th transmission / reception cycle and thereafter. The timing at which the communication control unit 14 of the terminal device 1 and the communication control unit 24 of the termination device 2 share this information is the Nth transmission / reception cycle.

[0134] The communication control unit 14 of the terminal device 1 and the communication control unit 24 of the terminating device 2 share information by transmitting and receiving signals in which a communication control signal is superimposed on a main signal. However, in this embodiment, the communication control unit 24 of the terminating device 2 generates the information and sends it to the communication control unit 14 of the terminal device 1, and then calculates T so as to satisfy any one of the above formulas (17) to (19). wakeup_N , Δt d_N , Δt u_N , or Δt d_u_N In this case, even if the communication control signal is transmitted only in the downstream direction, a minimum level of operation is possible.

[0135] As described above, the communication system according to the fifth embodiment includes a configuration in which the communication control unit 14 of the terminal device 1 and the communication control unit 24 of the terminating device 2 share information indicating a time period during which the terminating device 2 may transmit a downlink signal in the (N+1)th transmission / reception cycle. By including such a configuration, the communication system according to the fifth embodiment can easily detect the start time T wakeup_N , and the time during which it is in operation Δt d_N , Δt u_N , and Δt d_u_N Even if the frequency fluctuates for each transmission / reception cycle, it is possible to enable the terminal device 1 to receive the downstream signal normally.

[0136] According to the above-described embodiment, the communication device includes a communication unit and a control unit. For example, the communication device is the terminal device 1 in the embodiment, the communication unit is at least one of the functional units included in the terminal device 1 other than the communication control unit 14 in the embodiment, and the control unit is the communication control unit 14 in the embodiment.

[0137] The communication unit transmits and receives signals to and from another communication device. For example, the other communication device is the terminal device 1 in the embodiment. The control unit switches the communication unit from a dormant state to an active state by the time of receiving the signal, causes the communication unit to transmit the signal while the communication unit is in the active state, and switches the communication unit from the active state to a dormant state after the signal is transmitted and received.

[0138] The communication device may further include a control information superimposing unit. For example, the control information superimposing unit is the signal superimposing / separating unit 13 in the embodiment. In this case, the control information superimposing unit superimposes the control information on the signal transmitted from the communication unit. For example, the control information is a communication control signal in the embodiment. In this case, the control unit calculates the transmission timing of the signal in the other communication device so that the signal is received at the reception timing. In this case, the control information superimposing unit superimposes the control information indicating the transmission timing on the signal.

[0139] The communication device may further include a control information acquisition unit. For example, the control information acquisition unit is the signal superimposition / separation unit 13 in the embodiment. In this case, the control information acquisition unit acquires control information superimposed on a signal transmitted from another communication device. For example, the control information is a communication control signal in the embodiment. In this case, the control unit specifies the reception timing based on the transmission timing of the signal in the other communication device, which is included in the control information.

[0140] According to the above-described embodiment, the communication device includes a communication unit and a control unit. For example, the communication device is the termination device 2 in the embodiment, the communication unit is the network interface unit 21 in the embodiment, and the control unit is the communication control unit 24 in the embodiment.

[0141] The communication unit transmits and receives signals to and from another communication device. For example, the other communication device is the terminal device 1 in the embodiment. The control unit causes the communication unit to transmit a signal at a transmission timing determined so that the reception timing of the signal in the other communication device coincides with a timing when the other communication device is in a state in which it can receive a signal.

[0142] The communication device may further include a control information acquisition unit. For example, the control information acquisition unit is the signal superimposition / separation unit 23 in the embodiment. In this case, the control information acquisition unit acquires control information superimposed on a signal transmitted from another communication device. For example, the control information is communication control information in the embodiment. In this case, the control unit causes the communication unit to transmit a signal at a transmission timing based on the control information.

[0143] The communication device may further include a control information superimposing unit. For example, the control information superimposing unit is the signal superimposing / separating unit 23 in the embodiment. In this case, the control information superimposing unit superimposes control information including information indicating a transmission timing on a signal transmitted from the communication unit. For example, the control information is the communication control information in the embodiment.

[0144] At least one of the terminal device 1 and the termination device 2 in each of the above-mentioned embodiments may be realized in part or in whole by a computer. In that case, a program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to realize the function. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. The term "computer-readable recording medium" may also include a medium that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in that case. The above-mentioned program may be a program for realizing a part of the above-mentioned function, or may be a program that can realize the above-mentioned function in combination with a program already recorded in the computer system, or may be a program that is realized using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0145] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included.

[0146] The following supplementary notes are disclosed regarding the communication systems described in the above embodiments. (Appendix 1) A communication unit that transmits and receives signals to and from other communication devices; a control unit that switches the communication unit from a dormant state to an active state by a timing to receive the signal, causes the communication unit to transmit the signal while the communication unit is in the active state, and switches the communication unit from the active state to the dormant state after the signal is transmitted and received; A communication device comprising: (Appendix 2) a control information superimposing unit that superimposes control information onto the signal transmitted from the communication unit; Further equipped with the control unit calculates a transmission timing of the signal in the other communication device so that the signal is received at the reception timing; The control information superimposing unit superimposes the control information indicating the transmission timing onto the signal. 2. The communication device of claim 1. (Appendix 3) a control information acquisition unit for acquiring control information superimposed on the signal transmitted from the other communication device; Further equipped with The control unit specifies the reception timing based on a transmission timing of the signal in the other communication device, the transmission timing being included in the control information. 2. The communication device of claim 1. (Appendix 4) A communication unit that transmits and receives signals to and from other communication devices; a control unit that causes the communication unit to transmit the signal at a transmission timing that is determined so that a reception timing of the signal in the other communication device is a timing when the other communication device is in a state where it can receive the signal; A communication device comprising: (Appendix 5) a control information acquisition unit for acquiring control information superimposed on the signal transmitted from the other communication device; Further equipped with The control unit causes the communication unit to transmit the signal at the transmission timing based on the control information. 5. The communication device of claim 4. (Appendix 6) a control information superimposing unit that superimposes control information including information indicating the transmission timing on the signal transmitted from the communication unit; Further equipped 5. The communication device of claim 4. (Appendix 7) A communication step of transmitting and receiving signals to and from another communication device; a control step of switching the own device from a sleep state to an operating state by a timing to receive the signal, causing the own device to transmit the signal while the own device is in the operating state, and switching the own device from the operating state to the sleep state after the signal is transmitted and received; A communication control method comprising the steps of: (Appendix 8) A communication step of transmitting and receiving signals to and from another communication device; a control step of causing the own device to transmit the signal at a transmission timing determined so that a reception timing of the signal at the other communication device is a timing when the other communication device is in a state capable of receiving the signal; A communication control method comprising the steps of: (Appendix 9) The transmission timing is a transmission start time T wakeup_N +Δt wakeup +Δt d_N After that, and transmission end time T wakeup_N +Δt wakeup +Δt d_N +Δt u_N It is the timing that becomes the previous time. 3. A communication device as described in claim 2. Where: T wakeup_N is a start time of a wake-up state, which is a state during a transition from the sleep state to the operating state, in the N-th transmission / reception cycle, in the own device, Δt wakeup is the period during which the device is in the activated state, Δt d_N is a period during which the device itself is in the operating state capable of receiving the signal in the N-th transmission / reception cycle, Δt u_Nis a period during which the own device is in the operating state capable of transmitting the signal in the Nth transmission / reception cycle. (Appendix 10) The transmission timing is a transmission start time T wakeup_N +Δt wakeup +Δt u_N -Δt access After that, and transmission end time T wakeup_N +Δt wakeup +Δt u_N +Δt d_N -Δt access It is the timing that becomes the previous time. 3. A communication device as described in claim 2. Where: T wakeup_N is a start time of a wake-up state, which is a state during a transition from the sleep state to the operating state, in the N-th transmission / reception cycle, in the own device, Δt wakeup is the period during which the device is in the activated state, Δt d_N is a period during which the device itself is in the operating state capable of receiving the signal in the N-th transmission / reception cycle, Δt u_N is a period during which the device itself is in the operating state capable of transmitting the signal in the N-th transmission / reception cycle, Δt access is the one-way propagation time of the signal between the other communication device and the own device. (Appendix 11) The transmission timing is a transmission start time T wakeup_N +Δt wakeup -Δt access After that, and transmission end time T wakeup_N +Δt wakeup +Δt d_u_N -Δt access It is the timing that becomes the previous time. 3. A communication device as described in claim 2. Where: T wakeup_Nis a start time of a wake-up state, which is a state during a transition from the sleep state to the operating state, in the N-th transmission / reception cycle, in the own device, Δt wakeup is the period during which the device is in the activated state, Δt d_u_N is a period during which the device itself is in the operating state capable of transmitting and receiving the signal in the N-th transmission / reception cycle, Δt access is the one-way propagation time of the signal between the other communication device and the own device. (Appendix 12) The transmission timing is a transmission start time T wakeup_N +Δt wakeup +Δt d_N After that, and transmission end time T wakeup_N +Δt wakeup +Δt d_N +Δt u_N It is the timing that becomes the previous time. 5. The communication device of claim 4. Where: T wakeup_N is a start time of a wake-up state, which is a state during a transition from the sleep state to the operating state, in the N-th transmission / reception cycle, in the other communication device, Δt wakeup is the period during which the device is in the activated state, Δt d_N is a period during which the other communication device is in the operating state capable of receiving the signal in the N-th transmission / reception cycle, Δt u_N is a period during which the other communication device is in the operating state capable of transmitting the signal in the Nth transmission / reception cycle. (Appendix 13) The transmission timing is a transmission start time T wakeup_N +Δt wakeup +Δt u_N -Δt access After that, and transmission end time T wakeup_N +Δt wakeup+Δt u_N +Δt d_N -Δt access It is the timing that becomes the previous time. 5. The communication device of claim 4. Where: T wakeup_N is a start time of a wake-up state, which is a state during a transition from the sleep state to the operating state, in the N-th transmission / reception cycle, in the other communication device, Δt wakeup is the period during which the device is in the activated state, Δt d_N is a period during which the other communication device is in the operating state capable of receiving the signal in the N-th transmission / reception cycle, Δt u_N is a period during which the other communication device is in the operating state capable of transmitting the signal in the N-th transmission / reception cycle, Δt access is the one-way propagation time of the signal between the own device and the other communication device. (Appendix 14) The transmission timing is a transmission start time T wakeup_N +Δt wakeup -Δt access After that, and transmission end time T wakeup_N +Δt wakeup +Δt d_u_N -Δt access It is the timing that becomes the previous time. 5. The communication device of claim 4. Where: T wakeup_N is a start time of a wake-up state, which is a state during a transition from the sleep state to the operating state, in the N-th transmission / reception cycle, in the other communication device, Δt wakeup is the period during which the device is in the activated state, Δt d_u_N is a period during which the other communication device is in the operating state capable of transmitting and receiving the signal in the N-th transmission / reception cycle, Δt accessis the one-way propagation time of the signal between the own device and the other communication device. [Explanation of symbols]

[0147] 1... terminal device, 2... termination device, 3... transmission path, 4... switch, 5... optical splitter, 11... network interface section, 12... buffer section, 13... signal superposition / separation section, 14... communication control section, 15... user equipment interface section, 16... operation / measurement section, 21... network interface section, 22... buffer section, 23... signal superposition / separation section, 24... communication control section, 25... upper equipment interface section, 26... calculation section

Claims

1. A communication unit that transmits and receives signals to and from other communication devices; a control unit that switches the communication unit from a dormant state to an active state by a timing to receive the signal, causes the communication unit to transmit the signal while the communication unit is in the active state, and switches the communication unit from the active state to the dormant state after the signal is transmitted and received; a control information superimposing unit that superimposes control information onto the signal transmitted from the communication unit; Equipped with the control unit calculates a transmission timing of the signal in the other communication device so that the signal is received at the reception timing; the control information superimposing unit superimposes the control information indicating the transmission timing onto the signal; The transmission timing is a transmission start time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿Ｎ After that, and at the transmission end time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿Ｎ +Δt ｕ＿Ｎ It is the timing that becomes the previous time. Communications equipment. Where: T ｗａｋｅｕｐ＿Ｎ is a start time of a wake-up state, which is a state during a transition from the sleep state to the active state, in the N-th transmission / reception cycle, in the communication device, Δt ｗａｋｅｕｐ is the period during which the device is in the activated state, Δt ｄ＿Ｎ is a period during which the communication device is in the operating state capable of receiving the signal in the Nth transmission / reception cycle, Δt ｕ＿Ｎ is the period during which the communication device is in the operating state capable of transmitting the signal in the Nth transmission / reception cycle.

2. A communication unit that transmits and receives signals to and from other communication devices; a control unit that switches the communication unit from a dormant state to an active state by a timing to receive the signal, causes the communication unit to transmit the signal while the communication unit is in the active state, and switches the communication unit from the active state to the dormant state after the signal is transmitted and received; a control information superimposing unit that superimposes control information onto the signal transmitted from the communication unit; Equipped with the control unit calculates a transmission timing of the signal in the other communication device so that the signal is received at the reception timing; the control information superimposing unit superimposes the control information indicating the transmission timing onto the signal; The transmission timing is a transmission start time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｕ＿Ｎ -Δt ａｃｃｅｓｓ After that, and at the transmission end time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｕ＿Ｎ +Δt ｄ＿Ｎ -Δt ａｃｃｅｓｓ It is the timing that becomes the previous time. Communications equipment. Where: T ｗａｋｅｕｐ＿Ｎ is a start time of a wake-up state, which is a state during a transition from the sleep state to the active state, in the N-th transmission / reception cycle, in the communication device, Δt ｗａｋｅｕｐ is the period during which the device is in the activated state, Δt ｄ＿Ｎ is a period during which the communication device is in the operating state capable of receiving the signal in the Nth transmission / reception cycle, Δt ｕ＿Ｎ is a period during which the communication device is in the operating state capable of transmitting the signal in the Nth transmission / reception cycle, Δt ａｃｃｅｓｓ is the one-way propagation time of the signal between the other communication device and the communication device.

3. A communication unit that transmits and receives signals to and from other communication devices; a control unit that switches the communication unit from a dormant state to an active state by a timing to receive the signal, causes the communication unit to transmit the signal while the communication unit is in the active state, and switches the communication unit from the active state to the dormant state after the signal is transmitted and received; a control information superimposing unit that superimposes control information onto the signal transmitted from the communication unit; Equipped with the control unit calculates a transmission timing of the signal in the other communication device so that the signal is received at the reception timing; the control information superimposing unit superimposes the control information indicating the transmission timing onto the signal; The transmission timing is a transmission start time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ -Δt ａｃｃｅｓｓ After that, and at the transmission end time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿ｕ＿Ｎ -Δt ａｃｃｅｓｓ It is the timing that becomes the previous time. Communications equipment. Where: T ｗａｋｅｕｐ＿Ｎ is a start time of a wake-up state, which is a state during a transition from the sleep state to the active state, in the N-th transmission / reception cycle, in the communication device, Δt ｗａｋｅｕｐ is the period during which the device is in the activated state, Δt ｄ＿ｕ＿Ｎ is a period during which the communication device is in the operating state capable of transmitting and receiving the signal in the N-th transmission / reception cycle, Δt ａｃｃｅｓｓ is the one-way propagation time of the signal between the other communication device and the communication device.

4. A communication unit that transmits and receives signals to and from other communication devices; a control unit that causes the communication unit to transmit the signal at a transmission timing that is determined so that a reception timing of the signal in the other communication device is a timing when the other communication device is in a state where it can receive the signal; Equipped with The transmission timing is a transmission start time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿Ｎ After that, and at the transmission end time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿Ｎ +Δt ｕ＿Ｎ It is the timing that becomes the previous time. Communications equipment. Where: T ｗａｋｅｕｐ＿Ｎ is a start time of a wake-up state, which is a state during a transition from a sleep state to an active state, in the N-th transmission / reception cycle, in the other communication device, Δt ｗａｋｅｕｐ is the period during which the device is in the activated state, Δt ｄ＿Ｎ is a period during which the other communication device is in the operating state capable of receiving the signal in the N-th transmission / reception cycle, Δt ｕ＿Ｎ is a period during which the other communication device is in the operating state capable of transmitting the signal in the Nth transmission / reception cycle.

5. A communication unit that transmits and receives signals to and from other communication devices; a control unit that causes the communication unit to transmit the signal at a transmission timing that is determined so that a reception timing of the signal in the other communication device is a timing when the other communication device is in a state where it can receive the signal; Equipped with The transmission timing is a transmission start time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｕ＿Ｎ -Δt ａｃｃｅｓｓ After that, and at the transmission end time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｕ＿Ｎ +Δt ｄ＿Ｎ -Δt ａｃｃｅｓｓ It is the timing that becomes the previous time. Communications equipment. Where: T ｗａｋｅｕｐ＿Ｎ is a start time of a wake-up state, which is a state during a transition from a sleep state to an active state, in the N-th transmission / reception cycle, in the other communication device, Δt ｗａｋｅｕｐ is the period during which the device is in the activated state, Δt ｄ＿Ｎ is a period during which the other communication device is in the operating state capable of receiving the signal in the N-th transmission / reception cycle, Δt ｕ＿Ｎ is a period during which the other communication device is in the operating state capable of transmitting the signal in the N-th transmission / reception cycle, Δt ａｃｃｅｓｓ is the one-way propagation time of the signal between the communication device and the other communication device.

6. A communication unit that transmits and receives signals to and from other communication devices; a control unit that causes the communication unit to transmit the signal at a transmission timing that is determined so that a reception timing of the signal in the other communication device is a timing when the other communication device is in a state where it can receive the signal; Equipped with The transmission timing is a transmission start time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ -Δt ａｃｃｅｓｓ After that, and at the transmission end time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿ｕ＿Ｎ -Δt ａｃｃｅｓｓ It is the timing that becomes the previous time. Communications equipment. Where: T ｗａｋｅｕｐ＿Ｎ is a start time of a wake-up state, which is a state during a transition from a sleep state to an active state, in the N-th transmission / reception cycle, in the other communication device, Δt ｗａｋｅｕｐ is the period during which the device is in the activated state, Δt ｄ＿ｕ＿Ｎ is a period during which the other communication device is in the operating state capable of transmitting and receiving the signal in the N-th transmission / reception cycle, Δt ａｃｃｅｓｓ is the one-way propagation time of the signal between the communication device and the other communication device.

7. A communication step of transmitting and receiving signals to and from another communication device; a control step of switching the own device from a sleep state to an operating state by a timing to receive the signal, causing the own device to transmit the signal while the own device is in the operating state, and switching the own device from the operating state to the sleep state after the signal is transmitted and received; a control information superimposing step of superimposing control information onto the signal transmitted in the communication step; having In the control step, a transmission timing of the signal in the other communication device is calculated so that the signal is received at the reception timing; In the control information superimposing step, the control information indicating the transmission timing is superimposed on the signal; The transmission timing is a transmission start time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿Ｎ After that, and at the transmission end time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿Ｎ +Δt ｕ＿Ｎ It is the timing that becomes the previous time. Communications control method. Where: T ｗａｋｅｕｐ＿Ｎ is a start time of a wake-up state, which is a state during a transition from the sleep state to the operating state, in the N-th transmission / reception cycle, in the own device, Δt ｗａｋｅｕｐ is the period during which the device is in the activated state, Δt ｄ＿Ｎ is a period during which the device itself is in the operating state capable of receiving the signal in the N-th transmission / reception cycle, Δt ｕ＿Ｎ is the period during which the device itself is in the operating state capable of transmitting the signal in the Nth transmission / reception cycle.

8. A communication step of transmitting and receiving signals to and from another communication device; a control step of causing the own device to transmit the signal at a transmission timing determined so that a reception timing of the signal at the other communication device is a timing when the other communication device is in a state capable of receiving the signal; having The transmission timing is a transmission start time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿Ｎ After that, and at the transmission end time T ｗａｋｅｕｐ＿Ｎ +Δt ｗａｋｅｕｐ +Δt ｄ＿Ｎ +Δt ｕ＿Ｎ It is the timing that becomes the previous time. Communications control method. Where: T ｗａｋｅｕｐ＿Ｎ is a start time of a wake-up state, which is a state during a transition from a sleep state to an active state, in the N-th transmission / reception cycle, in the other communication device, Δt ｗａｋｅｕｐ is the period during which the device is in the activated state, Δt ｄ＿Ｎ is a period during which the other communication device is in the operating state capable of receiving the signal in the N-th transmission / reception cycle, Δt ｕ＿Ｎ is a period during which the other communication device is in the operating state capable of transmitting the signal in the Nth transmission / reception cycle.

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