JP7500242B2 - COMMUNICATION DEVICE, CONTROL METHOD FOR COMMUNICATION DEVICE, AND PROGRAM - Google Patents

Description

The present invention relates to a communication device, a control method for a communication device, and a program.

Various methods have been proposed for a communication device to determine a base station to connect to for communication. For example, a technology has been proposed in which a communication device determines a base station to connect to based on historical information about the location of the communication device (Patent Document 1). Also, a technology has been proposed in which a communication device connects to base stations operated by multiple communication carriers, acquires communication quality, and switches the connection to a base station with higher communication quality (Patent Document 2).

JP 2018-011326 A JP 2016-140081 A

In conventional technologies such as those in the above-mentioned documents, when a communication device can connect to base stations in multiple networks that provide different communication services, it is necessary to first connect to all base stations and then determine the base station that provides the intended communication service. As a result, it takes time and effort to determine the appropriate base station, and communication resources are wasted.

The present invention was made in consideration of the above problems, and aims to provide a technology for efficiently determining which base station to connect to.

As one means for achieving the above object, a communication device according to one aspect of the present invention has the following configuration: That is, the communication device has an acquisition means for acquiring, from broadcast information received from each of a plurality of base stations capable of communicating by a TDD (time division duplex) system, a TDD composition ratio, which is a ratio between an UL (uplink) communication time and a DL (downlink) communication time at each base station, as communication characteristics of each of the plurality of base stations, and a delay characteristic of each of the base stations , a determination means for determining a base station to connect to from among the plurality of base stations based on the communication characteristics of each of the base stations, and a connection processing means for performing connection processing with the determined base station .

The present invention provides a technique for efficiently determining which base station to connect to.

11 is a flowchart of a process executed by the communication device. 2 illustrates an example of a network configuration according to an embodiment. 1 shows an example of the configuration of a communication system. 2 shows an example of the hardware configuration of a base station. 1A shows an example of a hardware configuration of a communication device, and FIG. 1B shows an example of a functional configuration of the communication device. 13 is a flowchart of a process for determining a communication direction characteristic. 13 shows an example of the relationship between the UL/DL value and the communication direction characteristic. 13 is a flowchart of a process for determining delay characteristics. 2 shows an example of the relationship between subcarrier spacing and delay characteristics. 4 shows a communication sequence between a communication device and each base station. 13 shows an example of a relationship between base stations and communication characteristics. 1 shows an example of communication requirements for a communication device. An example of a connection priority table is shown (video viewing function). An example of a connection priority table (live video simultaneous distribution function) An example of a connection priority order table (remote photography (camera) function)

The following embodiments are described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe multiple features, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicate explanations are omitted.

<Network Configuration>
FIG. 2 is a diagram showing a network configuration 200 which is an example of a network configuration in this embodiment. The network configuration 200 is composed of a communication device 201, four communication systems 202 to 205, a video server 211, and a distribution server 212. The communication system 202 has a base station A1 206 and a base station A2 207, and provides a communication service A. The communication system 203 has a base station B1 208, and provides a communication service B. The communication system 204 has a base station C1 209, and provides a communication service C. The communication system 205 has a base station D1 210, and provides a communication service D. The operators providing the communication systems 202 to 205 (communication services A to D) are assumed to be operators A, B, C, and D, respectively. The video server 211 is a server which transmits image (still image/video) data to be viewed by the communication device 201, and is connected to the communication systems 202 to 205 via the Internet. The distribution server 212 is a server capable of providing data uploaded by the communication device 201 to other devices (eg, simultaneous distribution), and is connected to the communication systems 202 to 205 via the Internet.

The communication device 201 is arranged to be able to communicate with base station A1 206, base station B1 208, base station C1 209, and base station D1 210. The communication device 201 can communicate with a video server 211 and a distribution server 212 by connecting to a base station in any of the communication systems 202 to 205. Examples of the communication device 201 include a smartphone, a laptop, a mobile phone, and a mobile tablet.

Each base station in FIG. 2 is capable of communicating in a predetermined frequency band using a TDD (time division duplex) method that switches between uplink and downlink (communication direction from each base station to the communication device 201) communication over time. An uplink is a communication link from the communication device 201 to each base station, and a downlink is a communication link from each base station to the communication device 201. The base station is also capable of communicating with the communication device 201 using an OFDM (orthogonal frequency division multiplexing) method. The base station notifies the communication device 201 of TDD switching information including switching timing and switching pattern between the uplink and downlink, and information on subcarrier intervals (corresponding to the OFDM symbol length). The communication device 201 is capable of communicating using the TDD method and is capable of receiving TDD switching information and subcarrier interval information notified from the base station in FIG. 2.

Figure 3 shows an example configuration of a communication system 202 that provides communication service A. A communication service control unit 301 controls the entire service of communication service A. A communication service storage unit 302 stores control information, setting values, and communication characteristic information of communication service A. A gateway 303 is a gateway that connects the communication system 202 to the video server 211 and distribution server 212 via the Internet. Communication systems 203 to 205 can have a similar configuration to that shown in Figure 3, except for the number of base stations.

Figure 4 shows an example of the hardware configuration of the base station A1 206. The control unit 401 is composed of, for example, one or more CPUs (Central Processing Units), and controls the entire base station A1 206 by executing a program stored in the storage unit 402. The control unit 401 may control the entire base station A1 206 in cooperation with the program stored in the storage unit 402 and an OS (Operating System). The storage unit 402 is composed of both ROM and RAM, or either one of them, and stores various information such as programs for performing various operations described below and communication parameters for communication. In addition to memories such as ROM and RAM, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used as the storage unit 402. The transmission/reception unit 403 performs wireless transmission/reception processing via an antenna 404. The interface unit 405 communicates with the communication service control unit 301 and the gateway 303 in FIG. 3. The base station A2 207, the base station B1 208, the base station C1 209, and the base station D1 210 can also have the same hardware configuration as that in FIG. 4.

Figure 5 shows an example of the configuration of the communication device 201. Figure 5 (a) shows an example of the hardware configuration of the communication device 201. In Figure 5 (a), the control unit 501 is composed of, for example, one or more CPUs, and controls the entire communication device 201 by executing a program stored in the storage unit 502. The control unit 501 may control the entire communication device 201 in cooperation with the program stored in the storage unit 502 and the OS. The storage unit 502 is composed of both ROM and RAM, or either one, and stores various information such as programs for performing various operations described below, communication parameters for communication, and information on the functions and applications of the communication device 201. The information on the functions and applications of the communication device 201 includes communication requirements for the functions and applications. In addition to memories such as ROM and RAM, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used as the storage unit 502. The transmitting/receiving unit 503 performs wireless transmission and reception processing via the antenna 504. The display unit 505 displays various information. For example, the display unit 505 displays information on the functions and applications of the communication device 201 and displays information related to the settings of the communication device 201. The input unit 506 accepts input of information on the functions and applications of the communication device 201 and settings of the communication device 201 by the user. The display unit 505 and the input unit 506 may be configured as a single module and function as a GUI (Graphic User Interface).

FIG. 5B shows an example of a functional configuration executed by the control unit 501. The analysis unit 511 analyzes the signal received by the transmission/reception unit 503 and acquires (extracts) information necessary for subsequent processing. The creation unit 512 creates a list of base stations to be connected to, with priority order (hereinafter, a connection priority order table), based on the analysis result by the analysis unit 511 and the information stored in the storage unit 502. The connection processing unit 513 determines (selects) a base station to connect to from the connection priority order table created by the creation unit 512, and performs connection processing via communication by the transmission/reception unit 503. After the connection processing with the base station is completed, the communication characteristic confirmation unit 514 confirms the communication characteristics of the communication service provided by the system in which the base station is located. The position/attitude acquisition unit 515 acquires information on the position/attitude of the communication device 201 based on data obtained from a GPS sensor (position sensor) or a geomagnetic sensor (orientation sensor) (not shown). The position/attitude information of the communication device 201 can be reflected by the control unit 501 in the communication requirements of the function or application that the communication device 201 is to execute. The function execution unit 516 executes functions and applications, and transmits and receives data via the transmission/reception unit 503. Note that in this embodiment, functions and applications are objects executed by the communication device 201, and are used as terms with similar meanings.

<Processing flow by communication device>
Next, the flow of processing by communication device 201 will be described. Fig. 1 shows a flowchart of processing executed by communication device 201. The processing of this flowchart can be executed when communication device 201 attempts to execute a function or application by using any of the communication services provided by communication systems 202 to 205. The flowchart shown in Fig. 1 can be realized by a control unit 501 of communication device 201 executing a control program stored in a storage unit 502, and performing calculations and processing of information and control of each piece of hardware.

In S101, the transceiver 503 receives broadcast information (broadcast signal) from a base station with which the communication device 201 can communicate (any of base station A1 206, base station B1 208, base station C1 209, and base station D1 210). The broadcast information includes the above-mentioned TDD switching information (switching timing and switching pattern between uplink and downlink) and information on the subcarrier interval (corresponding to the OFDM symbol length).

S102 and S103 are processes for determining the communication characteristics of the base station. In S102, the analysis unit 511 acquires switching information from the received broadcast information, and determines the communication direction characteristics of the base station based on the switching information. The process of S102 will be described later with reference to Figures 6 and 7. In S103, the analysis unit 511 acquires information on subcarrier spacing from the received broadcast information, and determines the delay characteristics of the base station based on the information on subcarrier spacing. The process of S103 will be described later with reference to Figures 8 and 9. Note that the order of the processes of S102 and S103 may be reversed, or they may be performed simultaneously.

In S104, the control unit 501 determines whether the analysis process (S102, S103) for the notification information received from all base stations with which the communication device 201 can communicate has been completed. If the analysis process for the notification information received from all base stations has been completed (Yes in S104), the process proceeds to S105; if not (No in S104), the process returns to S101.

In S105, the analysis unit 511 compares the communication characteristics of the base station obtained by the processes of S102 and S103 with the communication requirements of the function or application that the communication device 201 is to execute. Next, in S106, the creation unit 512 creates a connection priority order table for multiple base stations with which communication is possible, based on the comparison result in S105 and the communication requirements of the function or application that the communication device 201 is to execute. In S107, the connection processing unit 513 selects the top base station in the connection priority order table created by the creation unit 512, and attempts to establish a connection with the selected base station. Details of the connection establishment process will not be described. After the connection attempt, in S108, the connection processing unit 513 determines whether the connection with the selected base station was successful (whether a connection was established).

If the connection with the selected base station is successful (Yes in S108), the process proceeds to S109, and the communication characteristics confirmation unit 514 acquires the communication characteristics of the communication service provided by the communication system to which the base station belongs from the connected base station. For example, the communication characteristics confirmation unit 514 makes a request to the connected base station via the transmission/reception unit 503, and acquires the communication characteristics of the communication service in response. Information on the communication characteristics of the communication service is stored in the communication service storage unit 302 in the communication system to which the base station belongs, and the base station acquires the information on the communication characteristics via the communication service control unit 301 and transmits it to the communication device 201. Next, in S110, the communication characteristics confirmation unit 514 determines whether the communication characteristics of the acquired communication service match the communication requirements of the function or application that the communication device 201 is to execute. If the communication characteristics match the communication requirements (Yes in S110), the connection process shown in FIG. 1 is terminated, and if not (No in S110), the process returns to S107. After the connection process is completed, the function execution unit 516 can transmit and receive data via the transmission/reception unit 503.

If the connection with the selected base station is not successful (No in S108), or if the communication characteristics of the communication service do not match the communication requirements of the function or application to be executed (No in S110), the process returns to S107. In this case, the connection processing unit 513 selects the next base station (the base station listed next to the base station to which the connection was not successful) in the connection priority order table created by the creation unit 512, and attempts to establish a connection with the selected base station. Then, the processes of S108 to S110 are performed. Note that in S110, if the communication characteristics of the base station at the bottom of the connection priority order table do not match the communication requirements of the function or application to be executed, the connection processing unit 513 may be configured to connect to the base station at the top of the table. In addition, in such a case, the connection processing unit 513 may be configured to connect to the base station that has communication characteristics closest to the communication requirements of the function or application to be executed, among the base stations with which communication is possible.

In addition, in S104, instead of judging whether or not the analysis has been completed for all base stations with which the communication device 201 can communicate, the analysis may be judged to be completed for one or more base stations that satisfy other conditions. For example, the analysis may be judged to be completed for a predetermined number of base stations, one or more base stations whose received signal strength is equal to or greater than a certain value, or one or more base stations from which notification information can be received.

Next, the process of S102 in FIG. 1 (communication direction characteristic determination process) will be described with reference to FIG. 6 and FIG. 7. FIG. 6 is a flowchart of the communication direction characteristic determination process. In S601, the analysis unit 511 acquires TDD switching information (information including switching timing and switching pattern between uplink and downlink) from the broadcast information received by the transmission/reception unit 503. In S602, the analysis unit 511 acquires the ratio (TDD configuration ratio) of the uplink (UL) communication time (the number of (sub) frames used for the uplink) to the downlink (DL) communication time (the number of (sub) frames used for the downlink) from the TDD switching information. Specifically, the analysis unit 511 calculates and acquires the value of the UL communication time (referred to as "UL/DL") relative to the DL communication time as the TDD configuration ratio. Next, in S603, the analysis unit 511 determines whether the value of UL/DL is equal to or greater than a predetermined first threshold value. In this embodiment, the predetermined first threshold is set to 2.

If the UL/DL value is equal to or greater than the predetermined first threshold (i.e., 2 or greater) (Yes in S603), the process proceeds to S604; if not (No in S603), the process proceeds to S605. In S604, the analysis unit 511 determines that the communication characteristics are suitable for uploading, and stores the result of the determination in the storage unit 502. In S605, the analysis unit 511 determines whether the UL/DL value is equal to or less than a predetermined second threshold. In this embodiment, the predetermined second threshold is set to 1/2.

If the UL/DL value is equal to or less than the second threshold (i.e., 1/2 or less) (Yes in S605), the process proceeds to S606. If not (No in S605), the process proceeds to S607. In S606, the analysis unit 511 determines that the communication characteristics are download-oriented, and stores the result of the determination in the storage unit 502. In S607, the analysis unit 511 determines that the communication characteristics are bidirectional (uplink and downlink), and stores the result of the determination in the storage unit 502. Note that, in the example of FIG. 6, the communication characteristics are classified into three categories: upload-oriented, download-oriented, and bidirectional, but the number of categories may be increased as necessary. FIG. 7 is a table showing the relationship between the UL/DL value and the communication direction characteristics in the determination of the communication direction characteristics shown in FIG. 6.

Next, the process of S103 in FIG. 1 (delay characteristic determination process) will be described with reference to FIG. 8 and FIG. 9. FIG. 8 is a flowchart of the delay characteristic determination process. In S801, the analysis unit 511 acquires information on the subcarrier spacing of the OFDM method from the broadcast information received by the transmission/reception unit 503. The subcarrier spacing corresponds to the OFDM symbol length, and the wider the subcarrier spacing, the more the tracking ability for high-speed movement can be ensured, and the more effective it is in reducing delay. In S602, the analysis unit 511 determines whether the subcarrier spacing is equal to or greater than a predetermined first spacing. In this embodiment, the predetermined first spacing is 240 KHz.

If the subcarrier spacing is equal to or greater than the predetermined first spacing (i.e., equal to or greater than 240 KHz) (Yes in S802), the process proceeds to S803; if not (No in S802), the process proceeds to S804. In S803, the analysis unit 511 determines that the communication characteristics are ultra-low latency, and stores the result of the determination in the storage unit 502. In S804, the analysis unit 511 determines whether the subcarrier spacing is equal to or greater than the predetermined second spacing. In this embodiment, the predetermined second spacing is 60 KHz.

If the subcarrier spacing is equal to or greater than the second predetermined spacing (i.e., equal to or greater than 60 KHz) (Yes in S804), the process proceeds to S805; otherwise (No in S804), the process proceeds to S806. In S805, the analysis unit 511 determines that the communication characteristics are low-latency, and stores the result of the determination in the storage unit 502. In S806, the analysis unit 511 determines that the communication characteristics are normal-latency (not low-latency), and stores the result of the determination in the storage unit 502. Note that in the example of FIG. 8, the delay characteristics are classified into three categories: ultra-low latency, low latency, and normal latency, but the number of categories may be increased as necessary. FIG. 9 is a table showing the relationship between the subcarrier spacing and the delay characteristics in the determination of the delay characteristics shown in FIG. 8.

Figure 10 is a sequence diagram showing the procedure by which the communication device 201 receives notification information from multiple base stations with which it can communicate and establishes a connection with a selected base station. The multiple base stations with which the communication device 201 can communicate are base station A1 206, base station B1 208, base station C1 209, and base station D1 210.

In M1001, the communication device 201 receives notification information from the base station A1 206 and analyzes the notification information to acquire the communication characteristics (communication direction characteristics, delay characteristics) of the base station A1 206 (corresponding to the processing of S102 and S103 in FIG. 1). Similarly, in M1002 to M1004, the communication device 201 receives notification information from the base station B1 208, the base station C1 209, and the base station D1 210, respectively, and acquires the communication characteristics of each base station. The notification information can include information on companies A, B, C, and D, which are the operators providing the communication systems 202 to 205 (communication services A to D). An example of the relationship between each base station and the communication characteristics acquired in M1001 to M1004 is shown in FIG. 11.

In M1005, the communication device 201 determines the connection priority order of the base stations based on the communication characteristics of each base station obtained in the processes of M1001 to M1004 and the communication requirements of the functions and applications that the communication device 201 intends to execute. Then, the communication device 201 creates a connection priority order table based on the determined order (corresponding to the process of S106 in FIG. 1). FIG. 12 shows an example of the communication requirements of the functions and applications that the communication device 201 intends to execute, which are stored in the storage unit 502 of the communication device 201. The communication requirements can be stored in the storage unit 502 of the communication device 201. The communication requirements can be changed by the control unit 501 according to the operating state of the communication device 201 and the operating state of the functions and applications. The communication requirements can be changed by the control unit 501 according to the position and orientation information of the communication device 201 acquired by the position and orientation acquisition unit 515.

Here, an example of a connection priority table created by the communication device 201 based on the information shown in FIG. 11 and FIG. 12 will be described with reference to FIG. 13 to FIG. 15. FIG. 13 shows a connection priority table created when the function to be executed by the communication device 201 is video viewing (function ID=1 in FIG. 12). As shown in FIG. 12, the communication requirements for executing the function of video viewing are communication direction characteristic=download priority and delay characteristic=normal. The required communication requirement is delay characteristic=normal, but referring to FIG. 11, there is a base station D1 with a more advanced characteristic of communication direction characteristic=download-oriented and delay characteristic=low delay, so base station D1 has the highest priority. After base station D1, there is base station A1 with communication direction characteristic=download-oriented and delay characteristic=normal, and base station C1 with communication direction characteristic=two-way communication-oriented and delay characteristic=ultra-low delay. The lowest priority is given to base station B1 with communication direction characteristic=upload-oriented and delay characteristic=normal.

Figure 14 shows a connection priority order table created when the function that the communication device 201 is to execute is live shooting and simultaneous distribution (function ID = 2 in Figure 12). As shown in Figure 12, the communication requirements for executing the function of live shooting and simultaneous distribution are communication direction characteristic = upload priority and delay characteristic = normal. Referring to Figure 11, since there is base station B1 whose communication direction characteristic = upload-oriented and delay characteristic = normal, base station B1 has the highest priority order. Following base station B1 are base station C1 whose communication direction characteristic = bidirectional and delay characteristic = ultra-low delay, and base station D1 whose communication direction characteristic = download-oriented and delay characteristic = low delay. The lowest priority order is given to base station A1 whose communication direction characteristic = download-oriented and delay characteristic = normal.

Figure 15 shows a connection priority order table created when the function to be executed by the communication device 201 is remote photography (camera) (function ID = 3 in Figure 12). Note that remote photography (camera) is a function (application) in which the communication device 201 functions as a camera and uploads image data obtained by photography to a controller (not shown). As shown in Figure 12, the communication requirements for executing the function of remote photography (camera) are communication direction characteristics = upload priority and delay characteristics = low delay. Referring to Figure 11, there is a base station B1 whose communication direction characteristics = upload direction and delay characteristics = normal, so base station B1 has the highest priority order. After base station B1, there is base station C1 whose communication direction characteristics = bidirectional and delay characteristics = ultra-low delay, and base station D1 whose communication direction characteristics = download direction and delay characteristics = low delay. The lowest priority order is given to base station A1 whose communication direction characteristics = download direction and delay characteristics = normal.

Returning to the explanation of FIG. 10, let us assume that in M1005, the communication device 201 creates the connection priority order table shown in FIG. 13 when the function to be executed is video viewing (function ID=1 in FIG. 12). In M1006, the communication device 201 selects the base station D1 210 at the top of the connection priority order table shown in FIG. 13, and attempts to establish a connection by sending a connection request message to the base station D1 210 (corresponding to the processing of S107 in FIG. 1). When the base station D1 210 receives the connection request message from the communication device 201, in M1007, it sends a connection acceptance message as a response. When the communication device 201 receives the connection acceptance message from the base station D1 210, it can determine that the connection has been successful (corresponding to the case of Yes in the processing of S108 in FIG. 1).

Next, in M1008, the communication device 201 transmits to the base station D1 210 a communication characteristics information request message for the communication service D provided by the communication system 205 to which the base station D1 210 belongs. When the base station D1 210 receives the communication characteristics information request message for the communication service D from the communication device 201, in M1009, it returns information on the communication characteristics of the communication service D as a response. Specifically, the base station D1 210 acquires information on the communication characteristics of the communication service D stored in the communication service storage unit 302 in the communication system 205 via the communication service control unit 301 and transmits it to the communication device 201. When the communication device 201 receives the information on the communication characteristics of the communication service D (corresponding to the processing of S109 in FIG. 1), in M1010, it checks whether the communication characteristics of the communication service D match the communication requirements for video viewing (see FIG. 12) (corresponding to the processing of S110 in FIG. 1). When it is confirmed that the communication characteristics of communication service D meet the communication requirements for video viewing, communication device 201 transmits and receives data to and from base station D1 210. For example, communication device 201 can transmit and receive data to and from video server 211 via base station D1 210.

Note that in FIG. 10, the notification information received by the communication device 201 in M1001 to M1004 is shown as being one each, but if there is multiple notification information from each base station, it can be received multiple times. Also, in FIG. 10, the communication device 201 shows an example in which the communication characteristics of communication service D match the communication requirements for the function to be executed, but if they do not match, the sending and receiving and processing of messages M1006 to M1010 are repeated in the order of the base stations listed in the connection priority table.

In this way, according to this embodiment, it is possible to determine a base station that can provide a communication service suitable for the function or application to be executed before the communication device connects to each base station. This makes it possible to use communication resources efficiently and determine an appropriate base station to connect to.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention.

The present invention can also be realized by supplying a program that realizes one or more of the functions of the above-mentioned embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that realizes one or more functions.

201 Communication device, 511 Analysis unit, 512 Creation unit, 513 Connection processing unit, 514 Communication characteristics confirmation unit, 515 Position and attitude acquisition unit 516 Function execution unit

Claims (10)

1. A communication device, comprising:
an acquisition means for acquiring, from broadcast information received from each of a plurality of base stations capable of communicating by a TDD (time division duplex) system, a TDD composition ratio , which is a ratio between an uplink (UL) communication time and a downlink (DL) communication time in each of the plurality of base stations, and a delay characteristic of each of the base stations, as communication characteristics of each of the plurality of base stations ;
A determination means for determining a base station to connect to from among the plurality of base stations based on a communication characteristic of each of the base stations;
A connection processing means for performing a connection process with the determined base station;
A communication device comprising: The communication device according to claim 1, characterized in that the determination means determines, among the plurality of base stations, a base station having the TDD configuration ratio and the delay characteristics that match the communication requirements required for the function that the communication device is to execute, as the base station to connect to. The plurality of base stations are capable of communicating using an OFDM (orthogonal frequency division multiplexing) system,
The communication device according to claim 1 or 2, characterized in that the acquisition means determines the delay characteristics of each of the base stations based on subcarrier spacing in OFDM communication at each of the base stations acquired from the broadcast information. The communication device according to claim 3, characterized in that the acquisition means determines the delay characteristics of each of the base stations to be ultra-low delay, low delay, or normal delay based on the subcarrier spacing in communication using the OFDM method at each of the base stations. The communication device according to any one of claims 1 to 4, characterized in that when the communication requirements required for the function to be executed by the communication device include the communication direction to be prioritized being UL, the determination means determines, as the base station to be connected, a base station having the TDD composition ratio in which UL communication time is longer than DL communication time, and when the communication requirements include the communication direction to be prioritized being DL, the determination means determines, as the base station to be connected, a base station having the TDD composition ratio in which DL communication time is longer than UL communication time. a creating means for creating a priority order table indicating a priority order of base stations to be connected to the plurality of base stations based on communication characteristics of each of the base stations and communication requirements required for a function to be executed by the communication device ,
The determining means determines the base station listed highest in the priority order table as the base station to be connected;
6. The communication device according to claim 1 , wherein the connection processing means performs a process for connecting to the determined base station. When the connection processing means does not succeed in connecting to the determined base station, the determination means determines, in the priority order table, the base station listed next to the base station with which the connection was not successful, as the base station to be connected;
7. The communication device according to claim 6 , wherein the connection processing means performs a process for connecting to the determined base station. 8. The communication device according to claim 6 , wherein said creating means lists in said priority order table base stations in order of the communication characteristics which more closely match said communication requirements. A method for controlling a communication device, comprising:
an acquisition step of acquiring, from broadcast information received from each of a plurality of base stations capable of communicating by a TDD (time division duplex) system, a TDD composition ratio , which is a ratio between an uplink (UL) communication time and a downlink (DL) communication time in each of the plurality of base stations, and a delay characteristic of each of the base stations, as communication characteristics of each of the plurality of base stations ;
a determination step of determining a base station to connect to from among the plurality of base stations based on communication characteristics of each of the base stations;
a connection processing step of performing a connection process with the determined base station;
13. A method for controlling a communication device, comprising: A program for causing a computer to function as the communication device according to any one of claims 1 to 8 .

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