WO2018020820A1

WO2018020820A1 - Wireless device, communication device, control method, and communication control method

Info

Publication number: WO2018020820A1
Application number: PCT/JP2017/020219
Authority: WO
Inventors: 公也加藤; 佐藤　雅典
Original assignee: ソニー株式会社
Priority date: 2016-07-26
Filing date: 2017-05-31
Publication date: 2018-02-01
Also published as: JPWO2018020820A1; JP7056561B2

Abstract

[Problem] To make possible the realization of more efficient wireless communication. [Solution] Provided is a wireless device comprising a reception unit that receives a reception confirmation response transmitted by a communication device, and a control unit that sets a reception stand-by period starting from the time when the reception confirmation response was received, and makes the reception unit stand by for signal reception during the reception standby period.

Description

Wireless device, communication device, control method, and communication control method

The present disclosure relates to a wireless device, a communication device, a control method, and a communication control method.

In recent years, wireless sensor networks for collecting information by wireless communication from terminals having a sensor function have attracted attention. The wireless sensor network has a wide variety of uses, such as a purpose of confirming a position of an object of interest and a purpose of managing the behavior of the object of interest.

In a wireless communication system such as an existing cellular system and wireless LAN (Local Area Network), a base station such as a base station or an access point manages communication resources. For example, the master station periodically transmits a reference signal, determines a communication resource for the communication terminal on the slave station side, notifies the determined communication resource to the slave station according to a predetermined control protocol, Communication is performed using the reception result of the reference signal and the notified communication resource. By this management, it is possible to avoid or suppress interference between communications performed by a plurality of communication terminals. Patent Document 1 discloses a communication method that can appropriately control a reception standby period of a slave station and reduce power consumed for reception. In this method, the master station can grasp the next reception standby period by transmitting a signal including the next reception standby period information (control information) in the payload to the slave station. Reception processing can be avoided.

JP 2007-181094 A

However, in a wireless communication system, it is not always efficient for a master station to transmit a signal including a reception waiting period in a payload to a slave station. For example, the power of the slave station is consumed to receive the signal. In particular, it is assumed that the data transmitted by the communication device (terminal) belonging to the sensor network is a small amount of data of about several bytes. In this case, the power consumed for transmitting the control information is for data transmission. The ratio with respect to the electric power consumed will increase. Further, since the reception waiting period information is included in the payload, limited radio resources are consumed.

Accordingly, the present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a new and improved wireless device and communication device capable of realizing more efficient wireless communication. Another object is to provide a control method and a communication control method.

According to the present disclosure, a reception unit that receives a reception confirmation response transmitted by a communication device, a reception standby period is set based on a timing at which the reception confirmation response is received, and the reception is performed in the reception standby period. And a control unit that causes the unit to wait for signal reception.

Further, according to the present disclosure, a reception waiting period is set based on the reception of the reception confirmation response transmitted by the communication device, and the timing at which the reception confirmation response is received. A control method is provided comprising: waiting for reception.

Further, according to the present disclosure, a transmission unit that transmits a reception confirmation response to the wireless device, and a transmission timing of the signal with the transmission timing of the reception confirmation response as a starting point, the transmission timing of the signal And a control unit that causes the transmission unit to transmit the signal.

Further, according to the present disclosure, a transmission confirmation response is transmitted to a wireless device, a transmission timing of a signal is set based on a transmission timing of the reception confirmation response, and the signal is transmitted at the transmission timing of the signal. A communication control method is provided.

As described above, according to the present disclosure, more efficient wireless communication can be realized.

Note that the above effects are not necessarily limited, and any of the effects shown in the present specification, or other effects that can be grasped from the present specification, together with or in place of the above effects. May be played.

1 is a diagram illustrating a wireless communication system according to an embodiment of the present disclosure. It is a figure which shows UL data frame which a sensor terminal transmits. It is a figure which shows the reception confirmation response (ACK) frame which a base station transmits. It is a figure which shows the detection of the ACK frame by a sensor terminal. It is a figure which shows the detection of the ACK frame by a sensor terminal. It is a figure which shows the function structure of the sensor terminal which concerns on embodiment of this indication. 2 is a diagram illustrating a functional configuration of a base station according to an embodiment of the present disclosure. FIG. It is a flowchart which shows the operation | movement which a sensor terminal transmits a UL data frame and receives a DL data frame. It is a flowchart which shows the operation | movement which a base station receives UL data frame and transmits DL data frame. It is a figure which shows the outline | summary of offset. It is a figure which shows the ACK frame which a base station transmits. It is a figure which shows the detection of the ACK frame by a sensor terminal. It is a figure which shows the detection of the ACK frame by a sensor terminal. It is a flowchart which shows the operation | movement which a base station determines the transmission timing of DL data frame. It is a figure which shows the ACK frame which a base station transmits. It is a figure which shows the detection of the ACK frame by a sensor terminal. It is a figure which shows the detection of the ACK frame by a sensor terminal. It is a figure which shows the hardware constitutions of the sensor terminal and base station which concern on embodiment of this indication.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

The description will be made in the following order.
1. 1. Overview of wireless communication system 2. Configuration of each device Operation of each device 4. First modified example 5. Second modified example 6. Hardware configuration

<1. Overview of Wireless Communication System>
Embodiments of the present disclosure relate to a wireless communication system that forms a wireless sensor network. First, an overview of a wireless communication system according to an embodiment of the present disclosure will be described with reference to FIG.

(1-1. Configuration of Radio Communication System)
FIG. 1 is a diagram illustrating a wireless communication system according to an embodiment of the present disclosure. As illustrated in FIG. 1, the wireless communication system according to the embodiment of the present disclosure includes a plurality of base stations 200, a plurality of sensor terminals 100, and an application server 300.

The base station 200 has a function of performing wireless communication with the sensor terminal 100 and a function of performing wired communication with the application server 300. For example, the base station 200 performs wireless communication with the sensor terminal 100 located in the cell. In the example illustrated in FIG. 1, the base station 200A performs wireless communication with the

sensor terminals

100A, 100B, and 100C that are located in the cell of the base station 200A, and the base station 200B is a sensor that is located in the cell of the base station 200B. Wireless communication is performed with

terminals

100D, 100E, 100F, and 100G. In particular, the base station 200 according to the present embodiment receives sensor data from the sensor terminal 100 and transmits the sensor data to the application server 300.

The sensor terminal 100 has a sensor function and a function of performing wireless communication with the base station 200. For example, the sensor function can be realized by various sensors such as an acceleration sensor, a gyro sensor, a temperature sensor, an atmospheric pressure sensor, a sound pressure sensor, a pulse sensor, or a GPS (Global Positioning System). The sensor terminal 100 transmits the sensor data acquired by the sensor function to the base station 200.

The application server 300 receives the sensor data obtained by the sensor terminal 100 from the base station 200 and provides a service using the received sensor data. There are a wide variety of services using sensor data, such as a service for confirming the position of an object of interest and a service for managing the behavior of an object of interest. Regarding the service for confirming the position of interest, for example, an elderly person or a child wears the sensor terminal 100 having a GPS function, and the application server 300 acquires position information from the sensor terminal 100 via the base station 200. Thus, it is possible to provide the positions of the elderly and children to the family and the administration. Regarding the service for managing the behavior of interest, for example, the sensor terminal 100 having an acceleration sensor is attached to livestock such as cows and pigs, and the application server 300 receives information on the movement of livestock from the sensor terminal 100 via the base station 200. It is possible to manage the behavior of livestock on grazing land.

In the present embodiment, the sensor terminal 100 having a sensor function will be described as an example of a wireless device. However, the present embodiment can also be applied to a wireless device having no sensor function. For example, the wireless device may be supplied with data from an external device and transmit the supplied data to the base station 200. When the external device is a vending machine, the wireless device may be supplied with sales data from the vending machine and transmit the sales data to the base station 200. In the present embodiment, the base station 200 will be described as an example of a communication device.

(1-2. Overview of wireless communication)
The configuration of the wireless communication system according to the embodiment of the present disclosure has been described above. Next, an outline of wireless communication between the base station 200 and the sensor terminal 100 in the wireless communication system will be described.

-Communication resource The base station 200 and the sensor terminal 100 share the start timing of each communication resource divided on the time axis. The sharing can be realized, for example, when the base station 200 transmits a reference signal for time synchronization and the sensor terminal 100 receives the reference signal. However, when the sensor terminal 100 continuously receives the reference signal, corresponding power is consumed. For this reason, the base station 200 and the sensor terminal 100 may share the start timing of each communication resource based on the absolute time managed by each. For example, the sensor terminal 100 can acquire the absolute time by GPS reception processing.

-Long distance transmission In order to realize a wireless communication system at a lower cost, it is effective to widen a cell area covered by one base station 200, that is, long distance transmission. In long-distance transmission, the number of base stations 200 constituting the wireless communication system can be reduced.

Also, it is possible to reduce the cost of the sensor terminal 100 by designing the hardware of the sensor terminal 100 so that the maximum available transmission power is limited. However, when the transmission power is limited, the communicable distance is also limited. In this regard, there is H-ARQ (Hybrid-ARQ) employed in cellular communication, for example, as a technique in which the sensor terminal 100 performs long-distance transmission with low transmission power. H-ARQ is a technique for improving reception sensitivity by repeatedly transmitting the same frame on the transmission side and combining a plurality of frames by signal processing on the reception side.

More specifically, the sensor terminal 100 conforming to H-ARQ until a reception confirmation response (hereinafter referred to as “ACK”) frame is received from the base station 200 or until the number of transmissions reaches an upper limit. Send the frame repeatedly. The base station 200 performs frame synthesis every time a new frame is received, and transmits an ACK frame to the sensor terminal 100 when demodulation is successful. In this document, a wireless communication system according to the H-ARQ will be described. However, this is an example, and the present disclosure can be applied to various communication schemes.

Frame Configuration FIG. 2 is an explanatory diagram showing frames that the sensor terminal 100 transmits to the base station 200. As shown in FIG. 2, the frame transmitted by the sensor terminal 100 includes a preamble 10, an SFD (Sync Frame Detector) 11, a terminal ID 12, data 13, a CRC (Cyclic Redundancy Check) 14, a parity bit 15, and the like. ,including.

The preamble 10 is a signal pattern used for frame detection in the base station 200. The SFD 11 is a signal pattern indicating the start position of the payload (terminal ID 12 to parity bit 15) in the frame. The base station 200 detects the SFD 11 from the frame in which the preamble 10 is detected, thereby recognizing that the subsequent is the payload.

The terminal ID 12 is an ID of the sensor terminal 100 that transmits a frame. The ID may be a unique number of the sensor terminal 100, for example. The data 13 is data for use in the application server 300, and sensor data such as acceleration information and position information can be included in the data 13. The CRC 14 is used to determine whether or not reception of the frame has been successful. The parity bit 15 is a redundant bit generated according to the terminal ID 12, the data 13, and the CRC 14, and the use success of the parity bit 15 improves the frame reception success rate at the base station 200.

Subsequently, FIG. 3 is a diagram illustrating an ACK frame transmitted from the base station 200 to the sensor terminal 100. First, a code sequence 21 is generated by performing cyclic shift on a predetermined code sequence 20, and the code sequence 21 is used as a preamble. The ACK frame is composed only of the preamble and does not include a payload. The cyclic shift is a process of shifting the code constituting the frame in one direction (in the present embodiment, the direction from the beginning to the end of the frame). As shown in FIG. 3, by performing a cyclic shift on the code sequence 20, the code a that is the head of the code sequence 20 is shifted toward the end in the code sequence 21. In addition, the code b, which is the end of the code sequence 20, circulates to the top in the code sequence 21, and further shifts toward the end.

In this embodiment, the cyclic shift amount is determined by a part of the terminal ID that is identification information of the sensor terminal 100 that is the destination of the ACK frame. As an example, in FIG. 3, the cyclic shift amount is obtained by multiplying a value corresponding to the decimal number of the lower 5 bits of the terminal ID (0 to 31; hereinafter referred to as “terminal ID” for convenience) by a variable D. This is the value obtained. Thereby, the base station 200 can indicate the destination of the ACK frame by the cyclic shift amount. For example, in FIG. 3, the base station 200 can distinguish 32 sensor terminals 100 by the cyclic shift amount. Here, the variable D is a value set so that the amount of shift on the time axis caused by the D-bit cyclic shift is larger than the maximum propagation delay amount in the wireless communication system. The effect of this will be described later.

The code sequence used in the ACK frame is arbitrary as long as the code sequence has low or zero autocorrelation and cross-correlation. For example, an M series or a Zadoff-Chu series that is a type of CAZAC (Constant Amplitude Zero Auto-Correlation) series may be used.

-Method for Receiving ACK Frame Next, a method for the sensor terminal 100 to receive an ACK frame transmitted by the base station 200 will be described with reference to FIG. 4 and FIG. 4 and 5 are diagrams illustrating detection of an ACK frame by the sensor terminal 100. FIG.

As described above, the base station 200 generates an ACK frame by performing a cyclic shift based on the terminal ID of the sensor terminal 100 that is the destination of the ACK frame. In the example illustrated in FIG. 4, an ACK frame (hereinafter referred to as “ACK_A”) addressed to the sensor terminal 100 </ b> A whose terminal ID is 1 is D-bit cyclically shifted and the terminal ID is 3. An ACK frame addressed to the sensor terminal 100B (hereinafter referred to as “ACK_B”) is cyclically shifted by 3D bits.

The sensor terminal 100 outputs a baseband received signal by converting a radio signal including an ACK frame into an electric signal by an antenna and performing analog processing and down conversion on the electric signal. Then, the sensor terminal 100 detects the ACK frame by obtaining the correlation between the reference signal and the received signal. Here, the reference signal is a preamble that is the same code sequence as that used by the base station 200 and has not been cyclically shifted.

As for the calculation method of the correlation between the received signal and the reference signal, the sensor terminal 100 multiplies the discrete Fourier transform of the received signal and the complex conjugate discrete Fourier transform of the reference signal for each sample as shown in Equation (1). Then, CORR [k] is calculated as the multiplication result. RX [k] in equation (1) is the result of the discrete Fourier transform of the received signal, REF ^* [k] is the result of the discrete Fourier transform of the complex conjugate of the reference signal, and L is the discrete Fourier transform It represents the number of samples of interest.

Then, as shown in Expression (2), the sensor terminal 100 performs a discrete inverse Fourier transform on CORR [k] that is a multiplication result, and calculates corr [n] as a result. A correlation value is calculated by converting a complex signal into a power signal, and a peak of the correlation value is searched. Similar to Equation (1), L represents the number of samples subject to discrete Fourier transform.

Further, the sensor terminal 100 may search for the peak of the correlation value by calculating the correlation value with the received signal while shifting the reference signal on the frequency axis.

FIG. 5 shows the correlation value peaks of ACK_A and ACK_B detected by the sensor terminal 100. Due to the cyclic shift, a time difference occurs from the timing when the head of the ACK frame is received by the sensor terminal 100 to the timing when the peak of the correlation value is detected. For example, for ACK_A in FIG. 5, the time difference of the shift amount on the time axis caused by the D-bit cyclic shift from the timing when the head of ACK_A is received by the sensor terminal 100 </ b> A to the timing when the peak of the correlation value is detected. (Hereinafter, sometimes referred to as “time difference of D” for convenience) has occurred. As for ACK_B, a 3D time difference occurs from the timing when the head of ACK_B is received by the sensor terminal 100A to the timing when the peak of the correlation value is detected.

Since the sensor terminal 100A knows the terminal ID of its own terminal, it can specify the cyclic shift amount corresponding to the ACK frame addressed to its own terminal. Then, the sensor terminal 100A transmits an ACK frame to its own terminal because the correlation value peak is included in the time corresponding to the identified cyclic shift amount (hereinafter referred to as “detection window”). Judge that The sensor terminal 100B determines that the ACK frame is transmitted to the own terminal in the same manner. In the example shown in FIG. 5, the sensor terminal 100A uses D to 2D on the time axis as detection windows, and the sensor terminal 100B uses 3D to 4D on the time axis as detection windows.

Also, as described above, the variable D is set so that the amount of shift on the time axis caused by the cyclic shift of D bits is larger than the maximum propagation delay amount. Thereby, it is possible to prevent a situation in which the peak of the correlation value occurs outside the detection window of the sensor terminal 100 that is the destination of the ACK frame due to the influence of the propagation delay. As described above, the base station 200 can specify the destination of the ACK frame by cyclic shift, and the sensor terminal 100 can specify the ACK frame addressed to the terminal itself.

Here, the sensor terminal 100 may cyclically shift the reference signal in advance based on the terminal ID of the own terminal, and obtain the correlation with the received signal using the reference signal after the cyclic shift. In this case, a time difference due to the cyclic shift does not occur between the timing when the head of the ACK is received by the sensor terminal 100A and the timing when the peak of the correlation value is detected. For example, for ACK_A in FIG. 5, there is no time difference of D due to the cyclic shift.

In addition, the cyclic shift can be performed based on information other than the terminal ID as long as it is any information that can identify the sensor terminal 100. For example, the frequency of the carrier wave generated by the oscillator of the sensor terminal 100 includes a frequency error due to individual differences between the oscillators. Base station 200 may perform cyclic shift based on this frequency error. Since the sensor terminal 100 grasps the frequency error of its own terminal, it can specify the detection window.

Further, the base station 200 may specify the destination of the ACK frame by a method other than the cyclic shift. For example, the base station 200 may specify the destination according to the type of code sequence used for generating the ACK frame. More specifically, the base station 200 generates an ACK frame using a different code sequence for each destination sensor terminal 100. The sensor terminal 100 knows the code sequence for the terminal itself, and can detect the ACK frame by obtaining the correlation between the reference signal generated based on the code sequence and the received signal.

(1-3. Background)
In a wireless sensor network, it is important to reduce the power consumption of the sensor terminal 100. This is because a large work load is generated by performing battery replacement or charging for each of a large number of sensor terminals 100, and depending on the installation location of the sensor terminal 100, it may be difficult to perform battery replacement or the like.

Here, in order to reduce the power consumption of the sensor terminal 100, the technique of intermittent reception is effective. The intermittent reception is a technique for realizing a reduction in power consumption of the sensor terminal 100 by not performing reception standby constantly but only during a necessary period.

In the wireless sensor network, in order for the sensor terminal 100 to perform intermittent reception, the sensor terminal 100 needs to grasp the timing at which a signal is transmitted by some method. For example, a method in which the sensor terminal 100 grasps the transmission timing by the base station 200 transmitting control information including the signal transmission timing to the sensor terminal 100 is conceivable.

However, since this method assumes a system such as 3GPP HSDPA (Third Generation Partnership Project High Speed Speed Packet Access) or LTE (Long Term Evolution), which is a public network standard, is sufficiently long in the downlink. It is assumed that a lot of control information can be included in the payload.

On the other hand, in the wireless sensor network, it is not preferable for the sensor terminal 100 to process a long wireless frame because the power consumption of the sensor terminal 100 increases. Further, in an environment where radio resources are limited, it is not preferable that radio resources be devoted to transmission of control information.

Accordingly, the present disclosure person has created the embodiment of the present disclosure by paying attention to the above circumstances. According to the embodiment of the present disclosure, the sensor terminal 100 sets the reception waiting period for receiving other data frames (hereinafter referred to as “DL data frames”) from the timing of receiving the ACK frame as a starting point. Set and receive the DL data frame within this reception waiting period. On the other hand, base station 200 sets the transmission timing of the DL data frame starting from the timing at which the ACK frame is transmitted, and transmits the DL data frame at the transmission timing. As described above, transmission and reception of the DL data frame is controlled based on the ACK frame, so that more efficient wireless communication can be realized. Hereinafter, the configuration and operation of the embodiment of the present disclosure will be sequentially described in detail.

<2. Configuration of each device>
The outline of the wireless communication system has been described above. Subsequently, with reference to FIG. 6 and FIG. 7, the configuration of each device constituting the wireless communication system will be described.

(2-1. Configuration of sensor terminal)
First, the configuration of the sensor terminal 100 will be described with reference to FIG. FIG. 6 is a diagram illustrating a functional configuration of the sensor terminal 100 according to the embodiment of the present disclosure. The sensor terminal 100 includes a communication unit 110, an information providing unit 120, a detection unit 130, a signal processing unit 140, a storage unit 150, and a control unit 160. The communication unit 110 includes a transmission unit 111 and a reception unit 112.

(Transmitter)
The transmission unit 111 transmits a radio signal to the base station 200. More specifically, the transmission unit 111 up-converts a baseband transmission signal provided from the control unit 160, converts an electric signal obtained by the up-conversion into a radio signal by an antenna, and transmits the radio signal.

(Information provision department)
The information providing unit 120 includes one or more sensors and provides data for transmission to the base station 200. More specifically, the information providing unit 120 includes sensors such as a position sensor, an acceleration sensor, a gyro sensor, a temperature sensor, an atmospheric pressure sensor, a sound pressure sensor, and a pulse sensor, and the timing at which the value of the sensor data is changed, Alternatively, the sensor data is provided to the control unit 160 at a periodic timing.

(Receiver)
The receiving unit 112 receives a radio signal transmitted from the base station 200. More specifically, the receiving unit 112 converts a radio signal transmitted from the base station 200 into an electric signal by an antenna, performs analog processing and down-conversion on the electric signal, and thereby converts a baseband received signal. Output. The reception unit 112 provides this reception signal to the detection unit 130.

The receiving unit 112 receives an ACK frame or a DL data frame from the base station 200. The method for receiving the ACK frame is as described above. On the other hand, with respect to the DL data frame reception method, the reception unit 112 realizes intermittent reception by performing reception standby during a reception standby period that is set based on the timing at which the ACK frame is received.

More specifically, since the sensor terminal 100 knows the terminal ID of its own terminal, it can grasp the cyclic shift amount of the ACK frame. Therefore, the sensor terminal 100 can calculate the timing at which the head of the ACK frame reaches the sensor terminal 100 by back-calculating the time difference due to the cyclic shift from the timing when the peak of the correlation value of the ACK frame is observed. Then, the sensor terminal 100 sets a period after a predetermined time has elapsed from the timing at which the head of the ACK frame is received by the sensor terminal 100 as a reception standby period, and receives a DL data frame during this reception standby period. I do. For example, the sensor terminal 100 may set a period 100 milliseconds after the timing when the head of the ACK frame is received by the sensor terminal 100 as the reception standby period.

This eliminates the need for the base station 200 to transmit control information for sharing the reception standby period to the sensor terminal 100. Further, since the ACK frame does not include a payload, radio resources can be saved, and since the frame length of the ACK frame is short, power consumption for the sensor terminal 100 to process the ACK frame can be reduced.

(Detection unit)
The detection unit 130 detects an ACK frame from the reception signal provided from the reception unit 112 by the method described above. The DL data frame detection method is the same as the ACK frame detection method. When a DL data frame is detected, the detection unit 130 extracts a payload from the DL data frame based on the timing at which the correlation value peak is detected, and provides the payload to the signal processing unit 140.

(Signal processing part)
The signal processing unit 140 performs demodulation and error correction decoding on the payload provided from the detection unit 130. Whether or not the demodulation is successful is confirmed using a CRC included in the radio frame.

(Memory part)
The storage unit 150 stores the demodulated data provided by the signal processing unit 140.

(Control part)
The control unit 160 controls transmission / reception of the sensor terminal 100. More specifically, regarding the transmission, the control unit 160 generates a baseband signal for transmission using the sensor data provided from the information providing unit 120 and provides the baseband signal to the transmission unit 111. To do. Further, when an ACK frame addressed to the terminal itself is detected, the control unit 160 stops the transmission process by stopping the generation of the baseband signal. Regarding reception, the control unit 160 realizes intermittent reception by setting a reception standby period starting from the timing at which the ACK frame is received.

(2-2. Configuration of base station)
The configuration of the sensor terminal 100 has been described above. Next, the configuration of the base station 200 will be described with reference to FIG. FIG. 7 is a diagram illustrating a functional configuration of the base station 200 according to the embodiment of the present disclosure. The base station 200 includes a communication unit 210, a detection unit 220, a signal processing unit 230, a storage unit 240, a control unit 250, and a wired communication unit 260. The communication unit 210 includes a transmission unit 211 and a reception unit 212.

(Receiver)
The receiving unit 212 receives a radio signal transmitted from the sensor terminal 100. More specifically, the receiving unit 212 converts a radio signal transmitted from the base station 200 into an electric signal by an antenna, performs analog processing and down-conversion on the electric signal, and thereby converts a baseband received signal. Output. The reception unit 212 provides this reception signal to the detection unit 220.

(Detection unit)
The detection unit 220 detects a data frame including sensor data acquired by the sensor terminal 100 (hereinafter referred to as “UL data frame”) from the reception signal provided from the reception unit 212. The detection method of the UL data frame is the same as the detection method by the detection unit 130 of the sensor terminal 100. The detection unit 220 cuts out the payload from the UL data frame and provides this payload to the signal processing unit 230.

(Signal processing part)
The signal processing unit 230 functions as a demodulation unit, and performs demodulation and error correction decoding on the payload provided by the detection unit 220. In this embodiment, since the sensor terminal 100 repeatedly transmits wireless signals corresponding to the same sensor data, the signal processing unit 230 combines the payloads of a plurality of wireless signals repeatedly transmitted from the same sensor terminal 100. Attempt to demodulate the combined payload. The signal processing unit 230 uses the CRC 14 included in the payload to check whether demodulation is successful. When the demodulation is successful, the signal processing unit 230 provides the control unit 250 with information regarding the transmission source of the UL data frame that has been successfully demodulated. Then, the control unit 250 transmits an ACK frame to the sensor terminal 100 that is the transmission source.

(Memory part)
The storage unit 240 stores the demodulated data provided by the signal processing unit 230.

(Transmitter)
The transmission unit 211 transmits a wireless signal to the sensor terminal 100. More specifically, the transmission unit 211 up-converts the baseband transmission signal provided from the control unit 250, converts the electrical signal obtained by the up-conversion into a radio signal by the antenna, and transmits the radio signal.

(Control part)
When the demodulation by the signal processing unit 230 is successful, the control unit 250 generates an ACK frame and provides it to the transmission unit 211. As described above, the control unit 250 determines the cyclic shift amount using a part of the terminal ID of the sensor terminal 100 that is the destination of the ACK frame.

Further, the control unit 250 generates a DL data frame and provides it to the transmission unit 211. The control unit 250 controls the transmission unit 211 so that the DL data frame is transmitted at a timing after a predetermined time has elapsed from the transmission timing of the ACK frame. For example, the control unit 250 may control the transmission unit 211 to transmit the DL data frame 100 milliseconds after the transmission timing of the ACK frame.

(Wired Communication Department)
The wired communication unit 260 transmits the sensor data and the like included in the payload demodulated by the signal processing unit 230 to the application server 300. Thereby, the application server 300 can provide a service using sensor data.

<3. Operation of each device>
The configuration of each device has been described above. Subsequently, the operation of each apparatus will be described with reference to FIGS. 8 and 9.

(3-1. Operation of sensor terminal)
First, the operation of the sensor terminal 100 will be described with reference to FIG. FIG. 8 is a flowchart illustrating an operation in which the sensor terminal 100 transmits a UL data frame and receives a DL data frame.

First, in step S1000, the information providing unit 120 of the sensor terminal 100 provides sensor data to the control unit 160, and the control unit 160 generates a UL data frame using the sensor data. In step S1004, the transmission unit 111 transmits a UL data frame to the base station 200. In step S1008, the receiving unit 112 receives an ACK frame until a predetermined time has elapsed. In step S1012, when the detection unit 130 detects an ACK frame addressed to the terminal itself (step S1012 / Yes), the reception unit 112 pauses reception until a reception standby period set based on the reception timing of the ACK frame. (Step S1016). In step S1020, the reception unit 112 receives the DL data frame during the reception standby period.

In step S1012, when an ACK frame addressed to the own terminal is not detected (step S1012 / No), the control unit 160 checks the number of times that a UL data frame including the same sensor data is repeatedly transmitted. If the number of times of transmission has reached the upper limit (step S1024 / Yes), the UL data frame transmission process ends. If the number of transmissions has not reached the upper limit (step S1024 / No), in step S1004, the transmission unit 111 transmits a UL data frame (step S1028).

(3-2. Operation of base station)
The operation of the sensor terminal 100 has been described above. Next, the operation of the base station 200 will be described with reference to FIG. FIG. 9 is a flowchart illustrating an operation in which the base station 200 receives a UL data frame and transmits a DL data frame.

First, in step S1100, the reception unit 212 of the base station 200 receives a radio signal, and the detection unit 220 detects a UL data frame. In step S1104, the detection unit 220 acquires a payload from the UL data frame, and the signal processing unit 230 synthesizes a payload including the same data. In step S1108, the signal processing unit 230 performs reception signal processing on the combined payload. Received signal processing refers to the above-described demodulation and error correction decoding processes.

When the signal processing unit 230 confirms the failure of demodulation using the CRC 14 (step S1112 / No), the processing ends with the payload held (step S1116). The held payload is then used for the payload synthesis process in step S1104 when repeated transmission is performed.

In step S1112, when the signal processing unit 230 confirms the success of demodulation using the CRC 14 (step S1112 / Yes), in step S1120, the control unit 250 sets the timing for transmitting the DL data frame to the sensor terminal 100. decide. In the present embodiment, the control unit 250 operates so that the DL data frame is transmitted at a timing after a predetermined time has elapsed from the transmission timing of the ACK frame.

In step S1124, the control unit 250 generates an ACK frame. In step S1128, the transmission unit 211 transmits an ACK frame to the sensor terminal 100. In step S1132, the payload held for demodulation is deleted. In step S1136, the control unit 250 generates a DL data frame. In step S1140, the transmission unit 211 transmits a DL data frame to the sensor terminal 100, and the process ends.

<4. First Modification>
The operation of each device in the wireless communication system has been described above. Subsequently, a first modification example of the embodiment of the present disclosure will be described with reference to FIGS. 10 to 14.

In the above-described embodiment, it has been described that the reception standby period is a period after a predetermined time has elapsed from the reception timing of the ACK frame. In the first modification, the reception standby period is dynamically set with the reception timing of the ACK frame as a starting point.

First, the concept of offset will be described with reference to FIG. FIG. 10 is a diagram showing an outline of the offset in the first modification. As shown in FIG. 10, in the first modified example, the base station 200, the sensor terminal 100A, and the sensor terminal 100B perform signal transmission / reception based on a time interval called a time slot. One time slot may include a UL data frame, a UL data frame and an ACK frame, and a DL data frame.

Here, the offset is an interval length from when the base station 200 transmits an ACK frame to a certain sensor terminal 100 to when a DL data frame is transmitted to the sensor terminal 100, and is represented by the number of time slots. The offset shown in FIG. 10 is an offset corresponding to the sensor terminal 100A, and the offset in this case is 2.

In FIG. 10, the sensor terminal 100A and the sensor terminal 100B transmit UL data frames without leaving time slot intervals. However, this is only an example, and the sensor terminal 100 may transmit UL data frames with appropriate time slot intervals.

Here, the base station 200 sets an offset based on the reception status of the UL data frame. More specifically, the base station 200 determines in step S1120 “Determination of DL data frame transmission timing” in FIG. 9 a sensor terminal 100 other than the sensor terminal 100 that is the transmission destination of the ACK frame (hereinafter “other data”). It is confirmed whether or not the payload transmitted from the sensor terminal 100 ”is held. When the payload is held, the base station 200 determines that a UL data frame is being received from another sensor terminal 100, and when the payload is not held, the base station 200 It is determined that no UL data frame is being received from terminal 100.

When the UL data frame is not being received, the base station 200 transmits the DL data frame in the time slot immediately after the time slot in which the ACK frame is transmitted by setting the offset to 0. On the other hand, when the UL data frame is being received, the base station 200 predicts, for each sensor terminal 100, the remaining number of receptions necessary until the demodulation of the payload included in the currently received UL data frame is successful, The maximum value is set as an offset. Details of the offset setting method will be described later.

Next, the ACK frame in the first modification will be described with reference to FIG. FIG. 11 is a diagram illustrating an ACK frame transmitted by the base station 200.

As described above, in the first modification, the cyclic shift amount is determined according to the destination and offset of the ACK frame. As an example, in FIG. 11, base station 200 calculates a value obtained by multiplying offset (0 to 7) by variable D as the first cyclic shift amount, and performs cyclic shift on predetermined code sequence 30. Thus, the code sequence 31 is generated. Further, the base station 200 sets the total number of offsets (8 in total) and the variable to a value (0 to 7; hereinafter referred to as “terminal ID” for convenience) corresponding to the decimal number of the lower 3 bits of the terminal ID. A value obtained by multiplying D is calculated as the second cyclic shift amount, and the code sequence 32 is generated by cyclically shifting the code sequence 31. The code sequence 32 is used as a preamble, and the ACK frame includes only the preamble and does not include a payload.

Subsequently, detection of an ACK frame by the sensor terminal 100 will be described with reference to FIGS. 12 and 13. 12 and 13 are diagrams illustrating detection of an ACK frame by the sensor terminal 100. FIG.

In the example shown in FIG. 12, ACK_A addressed to the sensor terminal 100A having an offset of 2 and a terminal ID of 1 is shown. Since the first cyclic shift amount is 2D bits and the second cyclic shift amount is 8D bits by the above-described method, a total of 10D bit cyclic shifts are performed.

FIG. 13 shows the result of the detection unit 130 of the sensor terminal 100 calculating the correlation between the reference signal and the received signal. Due to the cyclic shift, a time difference of 10D occurs between the timing when the head of ACK_A is received by the sensor terminal 100A and the timing when the peak of the correlation value is detected.

Since the sensor terminal 100A knows the terminal ID of the terminal and the total number of offsets, the sensor terminal 100A can identify the detection window. Since the detection window includes the peak of the correlation value, the ACK frame is addressed to the terminal. Judge that it was sent. Further, the sensor terminal 100A can specify the offset based on the time within the detection window where the peak is included. More specifically, when calculating the second cyclic shift amount, a window for designating an offset in the detection window is generated by multiplying the total number of offsets. For example, in the example shown in FIG. 13, eight windows for designating offsets are generated in the detection windows 8D to 16D of the sensor terminal 100A. In the example shown in FIG. 13, the sensor terminal 100A can specify that the offset is 2 based on the fact that the peaks are included in 10D to 11D.

In the first modification, the sensor terminal 100 receives the DL data frame based on the offset specified by the ACK frame. More specifically, the sensor terminal 100 sets, as a reception standby period, one time slot after an interval corresponding to the offset from the time slot in which the ACK frame is detected as a starting point. Here, there may be a plurality of time slots set as the reception standby period. For example, the sensor terminal 100 sets a plurality of time slots as reception standby periods after a time slot after an interval corresponding to an offset, or before and after the time slot in which an ACK frame is detected. May be.

Subsequently, the operation of the base station 200 in the first modification will be described. The operation of the base station 200 is the same as that in FIG. 9 except for step S1120 “Determination of DL data frame transmission timing” in FIG. Hereinafter, with reference to FIG. 14, an operation for determining the transmission timing of the DL data frame in the first modification will be described. FIG. 14 is a flowchart illustrating an operation in which the base station 200 determines the transmission timing of the DL data frame.

First, in step S1200, the control unit 250 of the base station 200 determines whether or not a UL data frame from another sensor terminal 100 is being received. When the control unit 250 determines that the UL data frame from the other sensor terminal 100 is not being received (step S1200 / No), the control unit 250 sets the offset to 0 in step S1204. When the control unit 250 determines that the UL data frame from another sensor terminal 100 is being received (step S1200 / Yes), the control unit 250 detects the UL data frame being received in step S1208. Number of times (hereinafter referred to as “Ndet”).

In step S1212, the control unit 250 acquires an average value of SINR (Signal to Interference plus Noise Ratio) of the UL data frame being received. In step S1216, control unit 250 estimates the number of payload combinations (hereinafter referred to as “Ncomb”) necessary for demodulation based on the average value of SINR. In step S1220, control unit 250 calculates the number of remaining time slots necessary for demodulation (hereinafter referred to as “Nts”) using the calculation formula Nts = Ncomb−Ndet. The control unit 250 performs the processing from step S1208 to step S1220 for each sensor terminal 100 that is the transmission source of the currently received UL data frame, and sets the maximum value of Nts as an offset (step S1224).

By setting the offset by the above method, the time slot in which the DL data frame is transmitted and the time slot in which the UL data frame is received are less likely to overlap. Therefore, it is possible to reduce the possibility of radio signal interference.

Also, the base station 200 may specify the offset by a method other than the cyclic shift. For example, the base station 200 may specify an offset according to the type of code sequence used for generating an ACK frame. More specifically, a different code sequence is prepared for each offset, and the base station 200 performs a cyclic shift based on the terminal ID on the code sequence corresponding to the offset calculated by the above-described method, and ACK Generate a frame. The sensor terminal 100 can detect the ACK frame and specify the offset by obtaining the correlation between each reference signal generated based on the code sequence corresponding to each offset and the received signal.

<5. Second Modification>
The first modification has been described above. Subsequently, a second modification example of the embodiment of the present disclosure will be described with reference to FIGS. 15 to 17. First, the ACK frame in the second modification will be described with reference to FIG. FIG. 15 is a diagram illustrating an ACK frame transmitted by the base station 200.

In the second modification, the cyclic shift amount is determined by the destination of the ACK frame and the presence / absence of transmission of the DL data frame. As an example, in FIG. 15, the base station 200 multiplies a value corresponding to whether or not a DL data frame is transmitted (0 to 1. As an example, 1 indicates transmission and 0 indicates no transmission) by a variable D. The value obtained in this way is calculated as the first cyclic shift amount, and the code sequence 41 is generated by cyclically shifting the predetermined code sequence 40. Furthermore, the base station 200 sets the number of DL data frame transmission presence / absence patterns to a value corresponding to the decimal number of the lower 4 bits of the terminal ID (0 to 15; hereinafter referred to as “terminal ID” for convenience) ( A value obtained by multiplying the variable D) and a variable D is calculated as a second cyclic shift amount, and the code sequence 42 is generated by performing a cyclic shift on the code sequence 41. The code sequence 42 is used as a preamble, and the ACK frame includes only the preamble and does not include a payload.

Subsequently, detection of an ACK frame by the sensor terminal 100 will be described with reference to FIGS. 16 and 17. 16 and 17 are diagrams illustrating detection of an ACK frame by the sensor terminal 100. FIG.

In the example shown in FIG. 16, ACK_A addressed to the sensor terminal 100 </ b> A whose DL data frame is transmitted and whose terminal ID is 1 is shown. In ACK_A, the first cyclic shift amount is 1D bits, and the second cyclic shift amount is 2D bits. Therefore, a total of 3D bit cyclic shifts are performed.

FIG. 17 shows the result of the detection unit 130 of the sensor terminal 100 calculating the correlation between the reference signal and the received signal. Due to the cyclic shift, a 3D time difference occurs from the timing when the head of ACK_A is received by the sensor terminal 100A to the timing when the peak of the correlation value is detected.

Since the sensor terminal 100A knows the terminal ID of the own terminal, the detection terminal can be specified, and the peak of the correlation value is included in the detection window, so that it is determined that the ACK frame is transmitted to the own terminal. To do. Also, the sensor terminal 100A can specify whether or not to transmit a DL data frame based on the time within the detection window including the peak. More specifically, a window for designating the presence / absence of DL data frame transmission within the detection window by multiplying the total number of DL data frame transmission / non-transmission patterns in the calculation of the second cyclic shift amount. Is generated. For example, in the example shown in FIG. 17, two windows for designating whether or not to transmit a DL data frame are generated in the detection windows 2D to 4D of the sensor terminal 100A. In the example shown in FIG. 17, the sensor terminal 100A can specify that the DL data frame is transmitted based on the fact that the peak is included in 3D to 4D.

When the sensor terminal 100A specifies that the DL data frame is transmitted, the sensor terminal 100A implements intermittent reception by performing reception standby during a reception standby period set with the timing at which the ACK frame is received as a starting point. More specifically, the sensor terminal 100A sets a period after a predetermined time has elapsed from the timing at which the head of the ACK frame is received by the sensor terminal 100 as a reception standby period, and DL Wait for data frame reception. On the other hand, if the sensor terminal 100A specifies that no DL data frame is transmitted, the sensor terminal 100A does not set the reception standby period.

This eliminates the need for the base station 200 to transmit to the sensor terminal 100 control information for sharing the presence / absence of transmission of the DL data frame and the reception standby period. Further, since the ACK frame does not include a payload, radio resources can be saved, and since the frame length of the ACK frame is short, power consumption for the sensor terminal 100 to process the ACK frame can be reduced.

Also, by applying the first modification, it is possible to specify whether or not to transmit a DL data frame. For example, the fact that the correlation value peak is included in the period (15D to 16D) corresponding to the offset 7 in FIG. 13 may mean that no DL data frame is transmitted. The sensor terminal 100 does not set the reception standby period when the correlation value peak is included in the period (15D to 16D) corresponding to the offset 7. On the other hand, when the correlation value peak is included in the periods (8D to 15D) corresponding to the offsets 1 to 6, the sensor terminal 100 sets the reception standby period based on the offset in the same manner as in the first modification. Set. By this method, the base station 200 can share the transmission presence / absence of the DL data frame and the offset to the sensor terminal 100 using the ACK frame.

In addition, the base station 200 may specify whether or not to transmit the DL data frame by a method other than the cyclic shift. For example, the base station 200 may specify whether or not to transmit a DL data frame depending on the type of code sequence used for generating an ACK frame. More specifically, different code sequences are prepared for a case where a DL data frame is transmitted and a case where a DL data frame is not transmitted, and the base station 200 uses a code sequence used depending on whether or not a DL data frame is transmitted. To decide. Then, the base station 200 performs a cyclic shift based on the terminal ID for the code sequence to generate an ACK frame. The sensor terminal 100 obtains an ACK frame by obtaining a correlation between each received reference signal and a received signal based on a code sequence corresponding to a case where a DL data frame is transmitted and a case where a DL data frame is not transmitted. It is possible to detect and specify whether or not a DL data frame is transmitted.

<6. Hardware configuration>
Heretofore, embodiments and modifications of the present disclosure have been described. The above-described transmission / reception processing and the like are realized by cooperation of software and hardware of the sensor terminal 100 and the base station 200 described below.

FIG. 18 is a diagram illustrating a hardware configuration of the sensor terminal 100 and the base station 200 according to the embodiment of the present disclosure. As shown in FIG. 18, the sensor terminal 100 and the base station 200 include a CPU (Central Processing Unit) 901, a ROM (Read Only Memory) 902, a RAM (Random Access Memory) 903, an input device 908, and an output device. 910, a storage device 911, and a transmission / reception device 915.

The CPU 901 functions as an arithmetic processing unit and a control unit, and controls the overall operation within the sensor terminal 100 and the base station 200 according to various programs. Further, the CPU 901 may be a microprocessor. The ROM 902 stores programs used by the CPU 901, calculation parameters, and the like. The RAM 903 temporarily stores programs used in the execution of the CPU 901, parameters that change as appropriate during the execution, and the like. These are connected to each other by a host bus including a CPU bus. In cooperation with the CPU 901, ROM 902 and RAM 903 and software, the information providing unit 120, the detection unit 130, the signal processing unit 140, the control unit 160 of the sensor terminal 100, the detection unit 220 of the base station 200, the signal processing unit 230, and the control The function of the unit 250 is realized.

The input device 908 includes input means for inputting information such as a mouse, keyboard, touch panel, button, microphone, switch, and lever, and an input control circuit that generates an input signal based on the input by the user and outputs the input signal to the CPU 901. Etc. The administrator of the sensor terminal 100 and the base station 200 can input various data and instruct processing operations to the sensor terminal 100 and the base station 200 by operating the input device 908.

The output device 910 includes a display device such as a liquid crystal display (LCD) device, an OLED (Organic Light Emitting Diode) device, and a lamp. Furthermore, the output device 910 includes an audio output device such as a speaker and headphones. For example, the display device displays a captured image or a generated image. On the other hand, the audio output device converts audio data or the like into audio and outputs it.

The storage device 911 is a device for storing data. The storage device 911 may include a storage medium, a recording device that records data on the storage medium, a reading device that reads data from the storage medium, a deletion device that deletes data recorded on the storage medium, and the like. The storage device 911 stores programs executed by the CPU 901 and various data. Further, the storage device 911 implements the functions of the storage unit 150 of the sensor terminal 100 and the storage unit 240 of the base station 200.

The transmission / reception device 915 is a communication interface configured by, for example, a communication device for connecting to the sensor terminal 100 and the base station 200. The transmission / reception device 915 implements the functions of the communication unit 110 of the sensor terminal 100, the communication unit 210 of the base station 200, and the wired communication unit 260.

The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, but the technical scope of the present disclosure is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field of the present disclosure can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that it belongs to the technical scope of the present disclosure.

For example, each step in the processing of the sensor terminal 100 or the base station 200 in the present specification does not necessarily have to be processed in time series in the order described in the flowchart. For example, each step in the processing of the sensor terminal 100 or the base station 200 may be processed in an order different from the order described as the flowchart, or may be processed in parallel.

For example, Step S1120 “Determination of DL Data Frame Transmission Timing” in FIG. 9 may be performed in parallel with Steps S1124 to S1136, or may be performed between these processes. Further, step S1132 “deletion of held payload” may be performed in parallel with steps S1120 to S1140, or may be performed between these processes. Also, step S1136 “DL data frame generation” in FIG. 9 may be performed in parallel with steps S1120 to S1132, or between these processes.

It is also possible to create a computer program for causing hardware such as the CPU 901, ROM 902 and RAM 903 built in the sensor terminal 100 or the base station 200 to perform the same functions as the components of the sensor terminal 100 or the base station 200 described above. It is. A storage medium storing the computer program is also provided.

In addition, the effects described in this specification are merely illustrative or illustrative, and are not limited. That is, the technology according to the present disclosure can exhibit other effects that are apparent to those skilled in the art from the description of the present specification in addition to or instead of the above effects.

The following configurations also belong to the technical scope of the present disclosure.
(1)
A receiving unit for receiving a reception confirmation response transmitted by the communication device;
A control unit that sets a reception standby period starting from the timing at which the reception confirmation response is received, and causes the reception unit to wait for signal reception in the reception standby period.
Wireless device.
(2)
The control unit sets a period after a predetermined time has elapsed from the timing when the reception confirmation response is received as the reception waiting period.
The wireless device according to (1).
(3)
The wireless device includes:
A detection unit that detects a correlation between the reception confirmation response received by the reception unit and a reference signal;
The control unit specifies an interval length according to the timing of the correlation peak, and sets a period after the interval length has elapsed from a timing when the reception confirmation response is received as the reception waiting period.
The wireless device according to (1).
(4)
The detection unit detects the reception confirmation response based on identification information of the wireless device;
The wireless device according to (3).
(5)
The detection unit identifies a period for detecting the reception confirmation response based on the identification information, and detects the reception confirmation response based on the fact that the correlation peak is included in the period.
The wireless device according to (4).
(6)
Receiving a receipt acknowledgment sent by the communication device;
Setting a reception waiting period starting from the timing at which the reception confirmation response is received, and waiting for signal reception in the reception waiting period.
Control method.
(7)
A transmission unit that transmits a reception confirmation response to the wireless device;
A control unit that sets a signal transmission timing starting from the transmission timing of the reception confirmation response, and causes the transmission unit to transmit the signal at the signal transmission timing;
Communication device.
(8)
The control unit sets a time after a predetermined time has elapsed from the transmission timing of the reception confirmation response as the transmission timing of the signal;
The communication device according to (7).
(9)
A detection unit for detecting a signal including the same data transmitted a plurality of times by the wireless device;
A demodulator that obtains a payload from the detected signal, synthesizes the payload, and demodulates the combined payload; and
The communication device according to (7).
(10)
The control unit predicts a reception timing of a signal necessary for the demodulation processing to be successful for a payload included in an already detected signal, and sets a time point later than the reception timing as a transmission timing of the signal.
The communication device according to (9).
(11)
The control unit acquires the number of times of synthesis necessary for the demodulation process to be successful and the number of times of synthesis actually performed for each of the plurality of wireless devices, and the actual number of times obtained from the required number of synthesis Calculating the maximum value obtained by subtracting the number of synthesis, and predicting the reception timing based on the maximum value;
The communication device according to (10).
(12)
The control unit determines a change amount of a phase of the reception confirmation response based on identification information of a wireless device that is a transmission destination of the reception confirmation response, or information on transmission of the signal.
The communication device according to any one of (7) to (11).
(13)
The information regarding the transmission of the signal is information regarding the presence or absence of the transmission of the signal or the transmission timing of the signal.
The communication device according to (12).
(14)
Sending an acknowledgment to the wireless device;
Setting the transmission timing of a signal based on the transmission timing of the reception confirmation response, and causing the signal to be transmitted at the transmission timing of the signal,
Communication control method.

DESCRIPTION OF SYMBOLS 100 Sensor terminal 110 Communication part 120 Information provision part 130 Detection part 140 Signal processing part 150 Storage part 160 Control part 200 Base station 210 Communication part 220 Detection part 230 Signal processing part 240 Storage part 250 Control part 260 Wired communication part 300 Application server

Claims

A receiving unit for receiving a reception confirmation response transmitted by the communication device;
A control unit that sets a reception standby period starting from the timing at which the reception confirmation response is received, and causes the reception unit to wait for signal reception in the reception standby period.
Wireless device.
The control unit sets a period after a predetermined time has elapsed from the timing when the reception confirmation response is received as the reception waiting period.
The wireless device according to claim 1.
The wireless device includes:
A detection unit that detects a correlation between the reception confirmation response received by the reception unit and a reference signal;
The control unit specifies an interval length according to the timing of the correlation peak, and sets a period after the interval length has elapsed from a timing when the reception confirmation response is received as the reception waiting period.
The wireless device according to claim 1.
The detection unit detects the reception confirmation response based on identification information of the wireless device;
The wireless device according to claim 3.
The detection unit identifies a period for detecting the reception confirmation response based on the identification information, and detects the reception confirmation response based on the fact that the correlation peak is included in the period.
The wireless device according to claim 4.
Receiving a receipt acknowledgment sent by the communication device;
Setting a reception waiting period starting from the timing at which the reception confirmation response is received, and waiting for signal reception in the reception waiting period.
Control method.
A transmission unit that transmits a reception confirmation response to the wireless device;
A control unit that sets a signal transmission timing starting from the transmission timing of the reception confirmation response, and causes the transmission unit to transmit the signal at the signal transmission timing;
Communication device.
The control unit sets a time after a predetermined time has elapsed from the transmission timing of the reception confirmation response as the transmission timing of the signal;
The communication device according to claim 7.
A detection unit for detecting a signal including the same data transmitted a plurality of times by the wireless device;
A demodulator that obtains a payload from the detected signal, synthesizes the payload, and demodulates the combined payload; and
The communication device according to claim 7.
The control unit predicts a reception timing of a signal necessary for the demodulation processing to be successful for a payload included in an already detected signal, and sets a time point later than the reception timing as a transmission timing of the signal.
The communication apparatus according to claim 9.
The control unit acquires the number of times of synthesis necessary for the demodulation process to be successful and the number of times of synthesis actually performed for each of the plurality of wireless devices, and the actual number of times obtained from the required number of synthesis Calculating the maximum value obtained by subtracting the number of synthesis, and predicting the reception timing based on the maximum value;
The communication device according to claim 10.
The control unit determines a change amount of a phase of the reception confirmation response based on identification information of a wireless device that is a transmission destination of the reception confirmation response, or information on transmission of the signal.
The communication device according to claim 7.
The information regarding the transmission of the signal is information regarding the presence or absence of the transmission of the signal or the transmission timing of the signal.
The communication device according to claim 12.
Sending an acknowledgment to the wireless device;
Setting the transmission timing of a signal based on the transmission timing of the reception confirmation response, and causing the signal to be transmitted at the transmission timing of the signal,
Communication control method.