WO2019124436A1

WO2019124436A1 - Wireless communication device, processor, and communication method

Info

Publication number: WO2019124436A1
Application number: PCT/JP2018/046764
Authority: WO
Inventors: 義三佐藤
Original assignee: 京セラ株式会社
Priority date: 2017-12-21
Filing date: 2018-12-19
Publication date: 2019-06-27

Abstract

A wireless communication device according to one embodiment of the present invention performs wireless communication based on a Low Power Wide Area (LPWA) system. The wireless communication device is provided with a control unit constituted so as to determine, on the basis of a past access time when access was denied from an network in the past, whether or not the access time should be shifted when accessing the network.

Description

Wireless communication device, processor, and communication method

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

In the 3rd Generation Partnership Project (3GPP) standard, there are EAB (Extended Access Barring) and a transmission suppression function (Backoff) as techniques for suppressing network congestion (see Patent Documents 1 and 2).

In EAB, a base station restricts access to a network by a wireless communication apparatus by broadcasting a parameter (EAB parameter) for restricting access (see Non-Patent Document 1).

In Backoff, when access is requested from the wireless communication device, the network notifies the wireless communication device of a message for denying access in response to the detection of congestion. The message includes a timer value for suppressing re-transmission. The wireless communication device waits without accessing the network until the timer value expires (see Non-Patent Document 2).

The wireless communication apparatus according to one embodiment is a wireless communication apparatus that performs wireless communication of a low power wide area (LPWA) method. The wireless communication apparatus includes a control unit configured to determine whether to shift the access time when accessing the network based on the past access time when access is denied from the network in the past. .

The processor according to one embodiment is a processor for controlling a wireless communication apparatus that performs wireless communication of a low power wide area (LPWA) method. The processor executes a process of determining whether to shift the access time when accessing the network based on the past access time when the access was denied from the network in the past.

In a communication method according to one embodiment, a wireless communication apparatus performing wireless communication in a Low Power Wide Area (LPWA) mode accesses a network based on past access times when access was denied from the network in the past. And determining whether to shift the access time at the time of doing.

It is a figure which shows an example of a structure of a communication system. FIG. 2 is a diagram showing a protocol stack in the communication system. It is a figure which shows an example of a structure of LPWA communication apparatus. It is a figure which shows the structure of a base station. It is a flowchart for demonstrating the operation example 1 which concerns on embodiment. It is a flowchart for demonstrating the operation example 2 which concerns on embodiment.

[Overview of the embodiment]
With the spread of the Internet of Things (IoT), the demand for low power consumption and low cost wireless communication devices is increasing. In order to meet such demand, a low power wide area (LPWA), which is a wireless communication system that realizes long-distance communication while suppressing power consumption, has attracted attention. A wireless communication apparatus (hereinafter referred to as an LPWA communication apparatus) that performs wireless communication according to the LPWA scheme realizes power saving by stopping wireless communication in a period in which no data communication occurs.

Here, in a factory where many LPWA communication devices are used, it is assumed that the power supply to the LPWA communication device is stopped when the operation of the factory ends, and the power supply starts to the LPWA communication device when the operation of the factory starts. Do. In this case, many LPWA communication devices access the network all at once, which may cause congestion in the network.

As described above, EAB and Backoff are defined as techniques for suppressing network congestion.

However, in EAB, since the base station broadcasts EAB parameters, all LPWA communication devices can not access the network.

On the other hand, in Backoff, in response to the access from each LPWA communication device, the network notifies the LPWA communication device of a message for denying access. This LPWA communication device-network signaling may also cause network congestion.

The control unit may be configured to determine a shift time for shifting the access time using at least one of a random number and an identifier of the wireless communication device.

The control unit may be configured to use a priority to determine a shift time for shifting the access time.

The priority may be a value set by a user.

The priority may be a value determined by the control unit according to transmission information to the network.

The control unit determines a first shift time for shifting a first access time when accessing the network, performs access to the network at the first access time, and then accesses the network. It may be configured to determine a second shift time to shift the second access time at the time of The control unit may be configured to determine the second shift time to be shorter than the first shift time when the access to the network at the first access time is successful.

The wireless communication apparatus may further include a receiving unit that receives, from the network, information for determining whether to permit the wireless communication apparatus to determine whether to shift the access time.

(Configuration of communication system)
FIG. 1 is a diagram showing an example of the configuration of the communication system 1 according to the embodiment.

As shown in FIG. 1, the communication system 1 includes an LPWA communication apparatus (wireless communication apparatus) 100, a host device 200, and a wireless communication network 300.

The LPWA communication apparatus 100 performs LPWA wireless communication with the wireless communication network 300. The LPWA method is a wireless communication method that realizes long-distance communication while reducing power consumption. In the embodiment, as the LPWA method, an enhanced machine type communication (eMTC) method or an NB (Narrow Band) -IoT method defined in the 3GPP standard which is one of cellular communication standards is used. eMTC may be referred to as LTE category M1. NB-IoT may be referred to as LTE category NB1.

The eMTC system or the NB-IoT system limits the frequency bandwidth used for wireless communication to a narrow bandwidth in order to reduce the cost of the communication apparatus. Note that the frequency bandwidth available for NB-IoT wireless communication is narrower than the frequency bandwidth available for eMTC wireless communication.

The LPWA communication apparatus 100 may be installed outside the coverage of the normal area of the wireless communication network 300, for example, underground. Therefore, in both the eMTC method and the NB-IoT LPWA method, a coverage extension technique is used which extends the coverage by repeatedly transmitting the same signal.

Also, the LPWA communication apparatus 100 achieves power saving by stopping wireless communication in a period in which no data communication occurs. As such power saving techniques, there are eDRX (extended discontinuous reception) and PSM (power saving mode) defined in the 3GPP standard. eDRX extends the DRX cycle, which is the reception interval when the LPWA communication device 100 performs intermittent reception, thereby extending the period (off period) in which the LPWA communication device 100 turns the receiver off, thereby saving power. It will be realized. PSM realizes power saving by setting the LPWA communication apparatus 10 in a pseudo power-off state (PSM state) in which even intermittent reception is not performed. Hereinafter, the off period and the PSM state in the eDRX are collectively referred to as a “power saving state”.

When eDRX is applied, the LPWA communication apparatus 100 in an idle state, which is in a standby state, can notice paging which is a call from the wireless communication network 300. On the other hand, when PSM is applied, the LPWA communication apparatus 100 in the PSM state can not notice paging from the wireless communication network 300. The wireless communication network 300 knows whether the LPWA communication apparatus 100 is in the power saving state, and stores data addressed to the LPWA communication apparatus 100 while the LPWA communication apparatus 100 is in the power saving state.

The LPWA communication apparatus 100 is connected to the host device 200. Specifically, the LPWA communication apparatus 100 is directly connected to the host device 200 or indirectly connected to the host device 200 via a cable. The LPWA communication apparatus 100 performs wired communication with, for example, a Universal Asynchronous Receiver / Transmitter (UART) method or a Universal Serial Bus (USB) method with the host device 200.

The LPWA communication apparatus 100 may not be connected to the host device 200. The LPWA communication apparatus 100 may be a wireless communication apparatus independent of the host device 200, such as a wireless communication apparatus that performs wireless communication of the WWAN (Wireless Wide Area Network) method.

The host device 200 is a personal computer (PC), a sensor device, a meter device, a vending machine, or the like. The host device 200 executes an application for IoT. The host device 200 to which the LPWA communication apparatus 100 is connected can communicate with the wireless communication network 300 via the LPWA communication apparatus 100 even if the host apparatus 200 itself does not have the wireless communication function.

The wireless communication network 300 is a network managed by a telecommunications carrier. In an embodiment, the wireless communication network 300 has a configuration in accordance with the 3GPP standard. The wireless communication network 300 includes a base station 310, an MME (Mobility Management Entity) 320, and a GW (Gateway) 330.

The base station 310 performs LPWA wireless communication with the LPWA communication apparatus 100. The base station 310 is connected to the MME 320 and the GW 330.

The MME 320 communicates with the LPWA communication apparatus 100 using NAS (Non-Access Stratum) signaling via the base station 310 to thereby establish a tracking area (ie, an area unit to perform paging) in which the LPWA communication apparatus 100 is located. to manage. The MME 320 also determines whether the LPWA communication apparatus 100 is in a power saving state.

The GW 330 includes a PDN-GW (Packet Data Network Gateway) and an S-GW (Serving Gateway). The PDN-GW functions as an interface between the wireless communication network 300 and an external network (eg, the Internet). The S-GW performs data transfer control between the PDN-GW and the base station 310. The GW 330 cooperates with the MME 320, and accumulates data addressed to the LPWA communication apparatus 100 while the LPWA communication apparatus 100 is in the power saving state. When the LPWA communication apparatus 100 recovers from the power saving state, the GW 330 transfers data addressed to the LPWA communication apparatus 100 to the LPWA communication apparatus 100 via the eNB 200.

FIG. 2 is a diagram showing a protocol stack in the communication system 1 according to the embodiment. Here, the flow of processing of data from the external network (external server) to the LPWA communication device 100 / host device 200 will be described.

As shown in FIG. 2, the external server generates data in the application layer. Data generated in the application layer is encrypted by SSL (Secure Sockets Layer) and processed in the transport layer (UDP or TCP) and IP layer, and then wireless communication is performed by wired communication such as Ethernet (registered trademark). It is sent to the network 300.

The wireless communication network 300 receives data from the wireless communication network 300 by wired communication such as Ethernet, is subjected to routing processing and the like in IP layer and IP address management, and transmits to the LPWA communication device 100 via the wireless layer of the base station 310. Will be sent. The radio layer has a configuration conforming to the 3GPP standard, and includes a physical (PHY) layer, a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, and an RRC (Radio). Resource Control) layer.

The LPWA communication apparatus 100 receives data from the wireless communication network 300 via wireless layer and IP address management by wired communication such as Ethernet (registered trademark). The LPWA communication apparatus 100 has an IP layer, a transport layer (UDP or TCP), and SSL. The IP layer receives data in the form of IP packets via the wireless layer and IP address management, processes the received data in the transport layer (UDP or TCP), and performs decryption (decryption) by SSL.

The LPWA communication apparatus 100 transmits the decrypted data to the host device 200 via the USB or the UART. The host device 200 processes the data received from the LPWA communication apparatus 100 via the USB or UART by the application layer.

(Configuration of LPWA communication device)
FIG. 3 is a diagram showing the configuration of the LPWA communication apparatus 100. As shown in FIG.

As shown in FIG. 3, the LPWA communication apparatus 100 includes an antenna 110, a front end unit 120, a processor 130, a memory 140, and a power management unit 150. The host device 200, a User Identity Module (UIM) / Subscriber Identity Module (SIM) 160, and a sensor 170 can be connected to the LPWA communication apparatus 100 via an interface (not shown). The UIM / SIM 160 stores subscriber information and the like necessary for wireless communication with the wireless communication network 300. The sensor 170 measures, for example, temperature, humidity, barometric pressure, illuminance, acceleration, geomagnetism, and the like, and outputs a measured value. The LPWA communication apparatus 100 may further include a Global Navigation Satellite System (GNSS) receiver (for example, a Global Positioning System (GPS) receiver).

The antenna 110 is used to transmit and receive a radio signal. The front end unit 120 performs amplification processing, filter processing, and the like on the radio signal received by the antenna 110, converts the radio signal into a baseband signal, and outputs the baseband signal to the processor 130. Further, the front end unit 120 converts the baseband signal input from the processor 130 into a wireless signal, performs amplification processing and the like, and outputs the signal to the antenna 110.

The processor 130 performs various processing and control in the LPWA communication apparatus 100. The memory 140 includes volatile memory and non-volatile memory, and stores programs executed by the processor 130 and information used for processing by the processor 130.

Power management unit 150 includes a battery and its peripheral circuits. The power management unit 150 supplies drive power to the LPWA communication apparatus 100. When the LPWA communication apparatus 100 is connected to the host device 200 by USB, drive power may be supplied from the host device 200 by USB power feeding.

The processor 130 performs wireless communication with the wireless communication network 300 by the LPWA method. The processor 130 receives data transmitted using the UDP from the wireless communication network 300. When the processor 130 is connected to the host device 200, the processor 130 can transfer the received data addressed to the host device 200 to the host device 200.

The front end unit 120 and the processor 130 shift to a power saving state in which wireless communication is stopped in a period in which no data communication occurs. Since power supply to the front end unit 120 and the like can be stopped in the power saving state, power saving of the LPWA communication apparatus 100 can be realized.

The front end unit 120 and the processor 130 resume wireless communication after a predetermined time has elapsed since the transition to the power saving state. The predetermined time may be determined by the DRX cycle or may be determined by a timer value for PSM. The timer values for the DRX cycle and the PSM are information shared by the LPWA communication apparatus 100 and the MME 320. The processor 130 resumes wireless communication after a predetermined time has elapsed, and then receives data stored in the wireless communication network 300 (GW 330) while in the power saving state.

In the present specification, for convenience, the LPWA communication apparatus 100 executes the process executed by at least one of the antenna 110, the front end unit 120, the processor 130, the memory 140, and the power management unit 150 included in the LPWA communication apparatus 100. Description will be made as processing (operation).

(Configuration of base station)
FIG. 4 shows the configuration of base station 310. As shown in FIG.

As shown in FIG. 4, the base station 310 includes antenna (s) 311, a front end unit 312, a processor 313, a memory 314, and a power management unit 315.

The antenna (s) 311 are used to transmit and receive wireless signals. The front end unit 312 performs amplification processing, filter processing, and the like on the wireless signal received by the antenna 311, converts the wireless signal into a baseband signal, and outputs the baseband signal to the processor 313. Further, the front end unit 312 converts the baseband signal input from the processor 313 into a wireless signal, performs amplification processing and the like, and outputs the result to the antenna 311.

The processor 313 performs various processing and control in the base station 310. The processor 313 performs wireless communication with the LPWA communication apparatus 100 by the LPWA method. The processor 130 receives, from the LPWA communication apparatus 100, data to be transmitted using UDP. The processor 313 is connected to a network node (for example, the MME 320) in the wireless communication network 300 via a backhaul and communicates with the network node.

The memory 314 includes volatile memory and non-volatile memory, and stores programs executed by the processor 313 and information used for processing by the processor 313.

The power management unit 315 includes a battery and its peripheral circuits. The power management unit 315 supplies drive power to the base station 310. The power management unit 315 may be externally supplied with drive power.

In this specification, for convenience, the base station 310 executes processing performed by at least one of the antenna (s) 311, the front end unit 312, the processor 313, the memory 314, and the power management unit 315 that the base station 310 comprises. The process (operation) will be described.

(Operation according to the embodiment)
An operation example according to the embodiment will be described. Specifically, operation examples 1 and 2 will be described as an example.

(1) Operation example 1
An operation example 1 according to the embodiment will be described with reference to FIG. FIG. 5 is a flowchart for explaining an operation example 1 according to the embodiment.

As shown in FIG. 5, in step S101, in the LPWA communication apparatus 100, access to the network is triggered.

Here, the network is at least one of nodes (for example, a base station 310, an MME 320, and the like) configuring the wireless communication network 300.

Access to the network may be triggered by turning off the power of the LPWA communication apparatus 100. By starting power supply to the LPWA communication apparatus 100, access to the network may be triggered. The LPWA communication apparatus 100 may trigger access to the network in order to transition from the RRC idle state to the RRC connected state (connected state).

The access to the network may be access for attaching / registering to the network (initial access). The access to the network may be an access for transitioning from the RRC idle state to the RRC connected state (connected state) (random access procedure).

In step S102, the LPWA communication apparatus 100 determines whether it has access denial information (whether access denial information is stored).

The access denial information includes information on past access times when the LPWA communication apparatus 100 was denied access from the network in the past. The access denial information may be a list of access times when access is denied. The access denied information may include at least one of a date (year-month-day) on which the access was denied and a day of the week on which the access was denied. Date and day information may be associated with access time information.

If the LPWA communication apparatus 100 has the access denial information, the process of step S103 is performed. If not, the LPWA communication apparatus 100 executes the process of step S106.

In step S103, the LPWA communication apparatus 100 determines whether to shift the access time to start access to the network. The LPWA communication apparatus 100 determines whether to shift the access time based on the access denial information.

The LPWA communication apparatus 100 may determine to shift the access time, for example, when the difference between the past access time and the current time when access is denied is less than a threshold. Otherwise, the LPWA communication apparatus 100 may determine not to shift the access time.

The LPWA communication apparatus 100 may determine whether to shift the access time in consideration of the date (year-month-day) on which the access was denied and / or the day of the week on which the access was denied. Even if the difference between the past access time when access is denied and the current time is less than the threshold, the LPWA communication apparatus 100 has the current date on a specific day (for example, holidays (holidays), holidays, etc.) In the case of), it may be determined that the access time is not shifted. Otherwise, the LPWA communication apparatus 100 may determine to shift the access time.

When it is determined that the access time is to be shifted, the LPWA communication apparatus 100 executes the process of step S104. If not, the LPWA communication apparatus 100 executes the process of step S106.

In step S104, the LPWA communication apparatus 100 determines a shift time. The LPWA communication apparatus 100 may determine the shift time so that access to the network can be made, for example, within ± 50% of the timer value for retransmission suppression.

The LPWA communication apparatus 100 may determine the shift time, for example, using any of the following Equations 1-3.

Shift time = average value of timer values / 2 + (average value of HASH (UE ID) mod timer values) (Equation 1)
Shift time = average value of timer values / 2 + (average value of random number mod timer values) (Equation 2)
Shift time = average value of timer values + priority * (average value of random number mod timer values) / N (Equation 3)

The average value of the timer values is an average value of timer values for suppressing re-transmission received from the network in the past. The timer value is, for example, a value of T3346 (backoff timer). When the backoff timer starts, the LPWA communication apparatus can not access the network again until the backoff timer expires.

The UEID is an identifier of the LPWA communication apparatus 100. The UE ID is, for example, one of an International Mobile Subscriber Identity (IMSI), an International Mobile Equipment Identifier (IMEI), and a Mobile Equipment Identifier (MEID).

The LPWA communication apparatus 100 can determine the shift time using at least one of a random number and a UEID. As a result, the values (random numbers and UEIDs) used by each LPWA communication apparatus 100 to calculate the shift time are basically different. Therefore, even if access to the network is triggered in the plurality of LPWA communication devices 100 at the same timing, the timing to start the access to the network can be shifted between the LPWA communication devices 100.

The priority is, for example, one of 1, 2, ..., N. “N” is a natural number, which is a value corresponding to the number of priorities. In Equation 3 above, the lower the priority value, the higher the priority. Therefore, in Equation 3, the higher the priority, the shorter the shift time.

The priority may be a value set by the user. Thereby, the user who owns the LPWA communication apparatus 100 can flexibly determine the priority.

The priority may be a value determined by the LPWA communication apparatus 100 according to transmission information to the network. The transmission information may be, for example, a measurement value acquired by a sensor, or may be information acquired by an application.

For example, when the transmission information is information indicating a failure of a sensor, the LPWA communication apparatus 100 may determine high priority. If the transmitted information is a measurement obtained by a sensor, the LPWA communication device 100 may determine a lower priority.

If the transmission information is a measured value for which early reporting is required (for example, information on breakage / deterioration of contents measured by a sensor, etc.), the LPWA communication apparatus 100 may determine high priority. If the transmitted information is a measurement (eg, temperature, humidity, etc.) for which early reporting is not required, the LPWA communication device 100 may determine a lower priority. The method (algorithm) with which the LPWA communication apparatus 100 determines the priority may be set by the user.

The LPWA communication apparatus 100 can determine the shift time using the priority. The LPWA communication apparatus 100 may determine the shift time so that the shift time becomes shorter as the priority is higher. The LPWA communication apparatus 100 may determine the shift time so that the shift time becomes longer as the priority is lower. As a result, the LPWA communication apparatus 100 with high priority can make the timing to start access to the network earlier than the LPWA communication apparatus 100 with low priority.

In step S105, the LPWA communication apparatus 100 waits without accessing the network until the shift time has elapsed. The LPWA communication apparatus 100 executes the process of step S106 in accordance with the elapse of the shift time. The LPWA communication apparatus 100 may start a timer in which a value corresponding to the determined shift time is set. The LPWA communication apparatus 100 may execute the process of step S106 in response to the expiration of the timer.

In step S106, the LPWA communication apparatus 100 starts access to the network. Specifically, the LPWA communication apparatus 100 transmits information for accessing the network to the network. The information is, for example, an attach request message, a location registration request message, or a random access preamble signal.

The LPWA communication apparatus 100 can establish a connection with the network by accessing the network. After establishing a connection with the network, the LPWA communication apparatus 100 can transmit transmission information (for example, measurement values) to the network.

In step S107, the LPWA communication apparatus 100 determines whether access is denied from the network.

The LPWA communication apparatus 100 may determine that the access is denied, for example, when an access denial response including a timer (for example, T3346 timer) value for re-transmission inhibition is received from the network. When the LPWA communication apparatus 100 receives the access approval response from the network, it may determine that the access is not denied.

When the access is denied, the LPWA communication apparatus 100 executes the process of step S108.

When the access is not denied (the access is successful), the LPWA communication apparatus 100 establishes a connection with the network. The LPWA communication apparatus 100 transmits information to be transmitted to the network. The LPWA communication apparatus 100 ends the process.

In step S108, the LPWA communication apparatus 100 records or updates access denial information. Specifically, the LPWA communication apparatus 100 adds the time at which the information for accessing the network was transmitted to the access denial information. The LPWA communication apparatus 100 may add at least one of the date (year-month-day) on which the access was denied and the day of the week on which the access was denied to the access denial information.

In step S109, the LPWA communication apparatus 100 waits without accessing the network until the timer for re-transmission inhibition expires. When the timer expires, the LPWA communication apparatus 100 executes the process of step S106.

(2) Operation example 2
An operation example 2 according to the embodiment will be described with reference to FIG. FIG. 6 is a sequence diagram for explaining an operation example 2 according to the embodiment. The same parts as in the operation example 1 will not be described.

As shown in FIG. 6, in step S201, the network transmits information (shift information) for determining whether to permit the LPWA communication apparatus 100 to determine whether to shift the access time or not. May be notified.

The network may transmit shift information in a broadcast / group cast (eg, SIB (System Information Block)). The network may send shift information in unicast (eg, RRC reconfiguration message, NAS message).

The shift information is information indicating whether the network permits the LPWA communication apparatus 100 to shift. The shift information may be information indicating that the LPWA communication apparatus 100 permits the access time to be shifted. The shift information may be information indicating that the LPWA communication apparatus 100 refuses to shift the access time.

The LPWA communication apparatus 100 may determine whether to execute the process of step S202 according to the shift information. When the network permits the LPWA communication apparatus 100 to shift, the LPWA communication apparatus 100 may execute the process of step S202. When the network denies the shift of the LPWA communication apparatus 100, the LPWA communication apparatus 100 may execute the normal operation for accessing the network without performing the following processing.

Thus, the network may be able to control the shift of the LPWA communication device 100.

In step S202, the power of the LPWA communication apparatus 100 is switched from off to on. Thereby, in the LPWA communication apparatus 100, access to the network is triggered.

In step S203, the LPWA communication apparatus 100 determines a first shift time t1 for shifting the first access time when accessing the network.

The LPWA communication apparatus 100 waits for transmission of information for accessing the network (hereinafter, access request) until the first shift time t1 elapses from the first access time (for example, time of power on).

In step S204, the LPWA communication apparatus 100 transmits an access request to the network in response to the current time becoming the first access time.

In step S205, the network notifies the LPWA communication apparatus 100 of a response to the access request.

When the network approves the access request, the network notifies the LPWA communication apparatus 100 of an acknowledgment response. The LPWA communication apparatus 100 executes an operation to access the network in response to the receipt of the acknowledgment response.

The LPWA communication apparatus 100 stores the success of the first access and the first shift time t1. The LPWA communication apparatus 100 may store the first access time in the management list.

The management list may include access denial information. When the first access fails (that is, an access denial response is received), the LPWA communication apparatus 100 can store access denial information in addition to the first shift time t1 in the management list.

In step S206, as in step S202, the power of the LPWA communication apparatus 100 is switched from off to on.

In step S207, the LPWA communication apparatus 100 determines a second shift time t2 for shifting the second access time when accessing the network.

When the network access at the first access time is successful, the LPWA communication apparatus 100 determines the second shift time t2 to be shorter than the first shift time t1.

The LPWA communication apparatus 100 determines whether or not the first access (previous access) is successful based on the management list. When the previous access is successful, the LPWA communication apparatus 100 can determine the second shift time t2 to be shorter than the first shift time t1. When the first access time before the shift and the second access time before the shift are the same (or within a predetermined range), the LPWA communication apparatus 100 has succeeded in the previous access. The second shift time t2 may be determined to be shorter than the first shift time t1. As a result, the LPWA communication apparatus 100 can suppress waiting for network access more than necessary even though the access is successful.

If the previous access has failed, the LPWA communication apparatus 100 can determine the second shift time t2 as usual. If the previous access has failed, the LPWA communication apparatus 100 may determine the second shift time t2 to be longer than the first shift time t1.

In step S208, the LPWA communication apparatus 100 transmits an access request to the network in response to the current time having reached the second access time.

In step S209, as in step S205, the network notifies the LPWA communication apparatus 100 of a response.

(Summary)
As described above, the LPWA communication apparatus 100 determines whether to shift the access time when accessing the network based on the past access time when the access was denied from the network in the past. Therefore, when access to the network is triggered, the LPWA communication apparatus 100 can shift the access start time to the network as needed. Even if many LPWA communication apparatuses 100 operate at the same time, it can be suppressed that all the LPWA communication apparatuses 100 start the start to the network all at once. As a result, congestion of the network can be suppressed.

(Other embodiments)
Although the embodiment has been described as described above, it should not be understood that the statements and drawings that form a part of this disclosure limit this disclosure. Various alternative embodiments, examples and operation techniques will be apparent to those skilled in the art from this disclosure.

In the embodiment, an example in which the LPWA method is the eMTC method or the NB-IoT method has been described, but an LPWA method other than the eMTC method and the NB-IoT method may be used.

The entire content of Japanese Patent Application No. 2017-244767 (filed on December 21, 2017) is incorporated herein by reference.

Claims

A wireless communication apparatus that performs low power wide area (LPWA) wireless communication,
A wireless communication apparatus comprising: a control unit configured to determine whether to shift an access time when accessing a network based on past access times when access was denied from the network in the past.
The wireless communication apparatus according to claim 1, wherein the control unit is configured to determine a shift time for shifting the access time using at least one of a random number and an identifier of the wireless communication apparatus.
The wireless communication apparatus according to claim 1, wherein the control unit is configured to determine a shift time for shifting the access time using a priority.
The wireless communication apparatus according to claim 3, wherein the priority is a value set by a user.
The wireless communication apparatus according to claim 3, wherein the priority is a value determined by the control unit according to transmission information to the network.
The control unit
Determining a first shift time for shifting a first access time in accessing the network;
After performing access to the network at the first access time, it is configured to determine a second shift time for shifting a second access time when accessing the network;
The control unit is configured to determine the second shift time to be shorter than the first shift time when the access to the network at the first access time is successful. The wireless communication device according to.
The wireless communication apparatus according to claim 1, further comprising: a receiving unit that receives, from the network, information for determining whether the wireless communication apparatus permits determination of whether to shift the access time.
A processor for controlling a wireless communication apparatus performing wireless communication of a low power wide area (LPWA) system,
A processor that executes processing of determining whether to shift an access time when accessing a network based on a past access time when access is denied from the network in the past.
A communication method,
Whether the wireless communication device performing wireless communication of Low Power Wide Area (LPWA) mode shifts the access time when accessing the network based on the past access time when the access was denied from the network in the past A communication method comprising the step of determining