Communication apparatus and communication method

Abstract

To provide a communication apparatus capable of starting communication at an early stage.SOLUTION: A communication device includes a control unit that refers to a table indicating a channel state with a communication partner device and selects a frequency channel used for communication with the communication partner device, and a wireless unit that performs wireless communication based on a DigitalEnhancedCordlessTelecommunications (DECT) system by using the frequency channel, in which the control unit refers to the frequency channel of the table according to an order of frequency channels to be waited for by the communication partner device after determining communication with the communication partner device, and selects the frequency channel used for communication with the communication partner device.SELECTED DRAWING: Figure 12

Description

[Technical Field]

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

[0002] One wireless communication system is the DECT (Digital Enhanced Cordless Telecommunications) system. In the DECT system, communication is carried out using one of multiple communication channels (frequencies and slots). For example, a DECT handset scans the channel conditions of multiple communication channels, selects the communication channel with the best channel conditions (best channel), and communicates with the base unit. This enables communication with high communication quality between the DECT handset and base unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-100756 Summary of the Invention [Problem to be solved by the invention]

[0004] In DECT, the base station changes frequencies while waiting for communication from the handset. Therefore, if the best channel selected by the handset is far from the frequency channel the base station is waiting for, the handset's start of communication can be delayed.

[0005] For example, the parent device waits for communication from the child device while repeating frequency channels 0 to 9 in the order of "0, 1, 2, ..., 8, 9, 0, 1, 2, ...." Here, in order to communicate with the parent device, the child device selects frequency channel "1," which has good channel conditions, when the parent device's frequency channel is "2." In this case, the child device has to wait until the parent device's current frequency channel "2" switches to the next frequency channel "1" before starting communication.

[0006] Non-limiting embodiments of the present disclosure contribute to providing a communication device and a communication method that enable early start of communication. [Means for solving the problem]

[0007] A communication device according to one embodiment of the present disclosure includes a control unit that refers to a table indicating the channel state between the communication partner device and the communication partner device and selects a frequency channel to be used for communication with the communication partner device, and a radio unit that uses the frequency channel to perform wireless communication based on the DECT (Digital Enhanced Cordless Telecommunications) system, and after determining to communicate with the communication partner device, the control unit refers to the frequency channels in the table in the order of the frequency channels that the communication partner device waits for and selects the frequency channel to be used for communication with the communication partner device.

[0008] A communication method according to one embodiment of the present disclosure refers to a table indicating the channel status between a communication partner device, selects a frequency channel to be used for communication with the communication partner device, uses the frequency channel to perform wireless communication based on the DECT (Digital Enhanced Cordless Telecommunications) system, and after determining to communicate with the communication partner device, refers to the frequency channels in the table in the order of the frequency channels awaited by the communication partner device, and selects a frequency channel to be used for communication with the communication partner device.

[0009] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0010] According to an embodiment of the present disclosure, communication can be started early.

[0011] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a configuration diagram of a communication system according to an embodiment of the present disclosure. [Figure 2] Block diagram of the slave unit [Figure 3] Block diagram of the parent unit [Figure 4] Timing chart illustrating frequency channel synchronization [Figure 5] Diagram showing channel condition TB [Figure 6] Timing chart explaining communication channel selection for a child device [Figure 7] Diagram explaining calculation of threshold value [Figure 8] Flowchart showing the operation of transmitting control information in the parent unit [Figure 9] Flowchart showing the control operation of the standby frequency channel in the master unit [Figure 10] Flowchart showing the operation of receiving control information in the slave unit [Figure 11] Flowchart showing frequency channel control operations in a slave unit [Figure 12] Flowchart showing communication channel selection operation in a slave unit DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or redundant explanation of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0014] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0015] <System configuration> Fig. 1 is a configuration diagram of a communication system according to an embodiment of the present disclosure. As shown in Fig. 1, the communication system includes a slave unit 1 and a master unit 2. The slave unit 1 and the master unit 2 perform wireless communication based on the DECT system.

[0016] The communication system shown in FIG. 1 may be applied to, for example, a mobile phone system or an intercom system.

[0017] When the communication system shown in FIG. 1 is applied to an intercom system, handset 1 may be installed in front of each unit in an apartment building and connected to a monitoring device (intercom master unit) installed inside each unit. Master unit 2 may be installed, for example, on a corridor wall on each floor of the apartment building and connected to a calling device installed in the lobby of the apartment building. Handset 1 and master unit 2 may relay communication between the monitoring device installed inside the unit and the calling device installed in the lobby. For example, handset 1 and master unit 2 may relay voice data and image data. Handset 1 may be equipped with a call button.

[0018] The base unit 2 may wirelessly communicate with a plurality of slave units 1. The slave units 1 and the base unit 2 may be referred to as a communication device.

[0019] <Block configuration> 1. Block configuration of the slave unit 2 is a block diagram of the slave device 1. As shown in FIG.

[0020] The control unit 11 includes a channel selection unit 11a and a channel scan processing unit 11b.

[0021] The control unit 11 may be configured with a processor such as a CPU (Central Processing Unit). The control unit 11 may execute a program stored in a storage unit (not shown) to realize the functions of the channel selection unit 11a and the channel scan processing unit 11b.

[0022] The channel selector 11a refers to a channel state TB (TB: Table) described later, and selects a communication channel (frequency and slot) for the slave device 1 to communicate with the master device 2.

[0023] The channel scanning processing unit 11b scans the frequency (frequency channel) for receiving a radio signal and acquires a channel state TB, which will be described later. The channel state TB is stored in a storage unit (not shown). "Scan" may be interpreted as "monitor" or "switch." "Acquire" may be interpreted as "generate."

[0024] The radio unit 12 includes a radio transmitting unit 12a and a radio receiving unit 12b.

[0025] The wireless transmitting unit 12a transmits a wireless signal. The wireless transmitting unit 12a changes the transmission frequency of the wireless signal under the control of the control unit 11.

[0026] The wireless receiving unit 12b receives the wireless signal and changes the reception frequency of the wireless signal under the control of the control unit 11.

[0027] 2. Block configuration of the parent unit 3 is a block diagram of the base unit 2. As shown in FIG.

[0028] The control unit 21 includes a channel switching unit 21a and a control information generating unit 21b.

[0029] The control unit 21 may be configured by a processor such as a CPU, for example. The control unit 21 may execute a program stored in a storage unit (not shown) to realize the functions of the channel switching unit 21a and the control information generating unit 21b.

[0030] The channel switching unit 21a switches the reception frequency channel for receiving the wireless signal and receives the wireless signal from the slave device 1. For example, the channel switching unit 21a receives the wireless signal from the slave device 1 while repeating reception frequency channels 0 to 9 according to a predetermined rule such as "0, 1, 2, ..., 8, 9, 0, 1, 2, ...".

[0031] The control information generator 21b generates control information to be transmitted to the slave device 1. The control information includes channel number information indicating the number of reception frequency channels on which the master device 2 waits for communication from the slave device 1, and current channel information indicating the reception frequency channel of the master device 2 in the frame in which the control information is transmitted.

[0032] For example, when the base unit 2 waits for communication from the slave unit 1 on reception frequency channels 0 to 9 (when the channel switching unit 21a switches reception frequency channels 0 to 9), the channel number information is "10." For example, when the reception frequency channel of the base unit 2 in frame "m" (see, for example, FIG. 4) is "9," the current channel information included in the control information transmitted in frame "m" is "9."

[0033] Based on the received control information, the slave unit 1 can determine the receiving frequency channel of the base unit 2 after receiving the control information. For example, if the number of receiving frequency channels of the base unit 2 is "10" and the current receiving frequency channel is "9", the slave unit 1 can determine that after receiving the control information, the base unit 2 will cycle through the receiving frequency channels "9, 0, 1, 2, ..., 8, 9, 0, 1, ..." according to a predetermined rule.

[0034] The wireless unit 22 includes a wireless transmitting unit 22a and a wireless receiving unit 22b.

[0035] The wireless transmitting unit 22a transmits a wireless signal. The wireless transmitting unit 22a changes the transmission frequency of the wireless signal under the control of the control unit 21.

[0036] The wireless receiving unit 22b receives a wireless signal and changes the reception frequency of the wireless signal under the control of the control unit 21.

[0037] <Frequency channel synchronization> Fig. 4 is a timing chart illustrating frequency channel synchronization. The squares in Fig. 4 represent slots. One frame consists of, for example, 24 slots.

[0038] The first 12 slots of one frame are used for downstream communication (communication from base unit 2 to slave unit 1). The last 12 slots of one frame are used for upstream communication (communication from slave unit 1 to base unit 2).

[0039] The base unit 2 switches the receiving frequency channel (standby frequency channel) based on a predetermined rule while waiting for communication from the slave unit 1. For example, as shown by arrow A4a in Fig. 4, the base unit 2 waits for communication from the slave unit 1 while switching (repeatedly) the receiving frequency channels 0 to 9 in the order of "..., 7, 8, 9, 0, 1, ...".

[0040] As shown by arrow A4b in Fig. 4, the master device 2 transmits a signal (beacon signal) for the slave device 1 to detect the master device 2 in a predetermined slot of downstream communication. The beacon signal in a predetermined frame includes control information. For example, in Fig. 4, the beacon signal in frame "m" includes control information.

[0041] For example, when the power of the slave device 1 is turned on, the slave device 1 searches for the master device 2 (beacon signal) as shown by an arrow A4c in Fig. 4. When the slave device 1 receives the beacon signal, it detects the master device 2 as shown by an arrow A4d in Fig. 4.

[0042] The slave device 1 receives the control information after detecting the master device 2. For example, in Fig. 4, the control information is transmitted in frame "m", so that the slave device 1 that detects the master device 2 receives the control information at the timing indicated by arrow A4e in Fig. 4.

[0043] The control information transmitted in frame "m" in Figure 4 includes channel number information indicating the number of receiving frequency channels "10" on which the base unit 2 waits for communication from the slave unit 1, and current channel information indicating the waiting receiving frequency channel "9" of the base unit 2 in frame "m".

[0044] Upon receiving the control information, slave device 1 can understand that the standby receiving frequency channel of base device 2 will be repeated according to a predetermined rule. For example, in the example of Figure 4, slave device 1 can understand that after receiving the control signal in frame "m", the standby receiving frequency channel of base device 2 will be switched in the order of "0, 1, 2, ..., 8, 9, 0, 1, 2, ..." from frame "m+1" onwards.

[0045] Therefore, based on the control information, slave device 1 can synchronize its transmission frequency channel with the reception frequency channel of master device 2. For example, slave device 1 can switch its transmission frequency channel in the order of "0, 1, 2, ..., 8, 9, 0, 1, 2, ..." from frame "m+1" onwards.

[0046] In DECT communications, two slots spaced 12 slots apart are used as a pair of slots when communication is performed between the handset 1 and the base unit 2. For example, as shown by arrows A4f and A4g in Fig. 4, the pair of slots 2 and 14 is used for communication between the handset 1 and the base unit 2.

[0047] As will be explained in <Communication Channel Selection> below, when the slave device 1 decides to communicate with the base device 2, it refers to the channel state TB and determines the frequency channel and slot for communication with the base device 2. The frequency channel (frequency channel in use) of the slot used for communication between the slave device 1 and the base device 2 is fixed and may differ from the frequency channel on which the base device 2 stands by. This is because the frequency channel on which the base device 2 stands by is incremented each time a frame changes, as shown by arrow A4a in Fig. 4, but the frequency channel in use is fixed.

[0048] <Channel Status TB> FIG. 5 is a diagram showing the channel state TB. After detecting the base station 2 or receiving control information, the handset 1 acquires the channel state TB. For example, the handset 1 switches the frequency channel (receiving frequency channel of the handset 1) from 0 to 9 in each slot from 0 to 11 (each slot in downlink communication) and acquires the channel state of each frequency channel in each slot. Then, as shown in FIG. 5, the handset 1 acquires the channel state TB indicating the channel state of each frequency channel in each slot. The channel state TB may be acquired (updated) for example, every frame, or every frame at a predetermined interval.

[0049] The frequency of the frequency channel to which slave device 1 switches is the same as the frequency of the frequency channel on standby for master device 2. Therefore, the channel state of the frequency channel at slave device 1 can be considered to be the same as the channel state of the receiving frequency channel at master device 2 (reciprocity of the transmission path). For example, if the channel state of a certain frequency channel at slave device 1 is good, the channel state of a certain receiving frequency channel at master device 2 can also be considered to be good.

[0050] The channel condition may be, for example, interference power (dBm). For example, the channel condition may be considered to be better as the interference power is smaller.

[0051] As will be described in the next section <Communication Channel Selection>, the slave device 1 refers to the channel state TB and selects a communication channel (frequency and slot) to be used for communication with the master device 2. For example, the slave device 1 refers to the channel state TB and selects frequency channel "2" and slot "2" shown in the dotted line box A5a in Fig. 5. In this case, the slave device 1 transmits a wireless signal to the master device 2 on the communication channel of transmission frequency channel "2" and slot "14".

[0052] <Communication channel selection> FIG. 6 is a timing chart illustrating communication channel selection by slave unit 1. In FIG. 6, master unit 2 waits on receiving frequency channel "7" in frame "n-1." Master unit 2 waits on receiving frequency channel "8" in frame "n." Master unit 2 waits on receiving frequency channel "9" in frame "n+1." Master unit 2 waits on receiving frequency channel "0" in frame "n+2." Master unit 2 waits on receiving frequency channel "1" in frame "n+3."

[0053] After receiving control information from the base unit 2, if the handset 1 decides to communicate with the base unit 2, it refers to the channel state TB and determines the frequency channel and slot for communicating with the base unit 2. Here, if there is a good channel state in a frequency channel close to the reception frequency channel on which the base unit 2 waits, the handset 1 can start communication with the base unit 2 quickly.

[0054] For example, the slave device 1 decides to communicate with the master device 2 at the timing indicated by arrow A6a in Fig. 6 (standby receiving frequency channel "8" of the master device 2). In this case, if the channel state of frequency channel "8" in the channel state TB (see dotted line frame A5b in Fig. 5) includes a good channel state, the slave device 1 can communicate with the master device 2 using frequency channel "8". In other words, the slave device 1 can communicate with the master device 2 in frame "n" when it has decided to communicate with the master device 2.

[0055] Furthermore, even if the channel conditions of frequency channel "8" do not include a good channel condition, if the channel conditions of frequency channel "9" (see dotted line frame A5c in FIG. 5) include a good channel condition, slave device 1 can communicate with master device 2 using frequency channel "9." In other words, slave device 1 can communicate with master device 2 in frame "n+1," which is the next frame following frame "n" in which slave device 1 has decided to communicate with master device 2.

[0056] Furthermore, even if the channel conditions of frequency channels "8" and "9" do not include a favorable channel condition, if the channel conditions of frequency channel "0" (see dotted line frame A5d in FIG. 5) include a favorable channel condition, slave device 1 can communicate with base device 2 using frequency channel "0." In other words, slave device 1 can communicate with base device 2 in frame "n+2," which is two frames after frame "n" in which it has decided to communicate with base device 2.

[0057] In this way, the slave 1 can start communication with the master 2 quickly if there is a good channel condition in a frequency channel close to the reception frequency channel on standby for the master 2.

[0058] Therefore, when the slave device 1 decides to communicate with the base device 2, it refers to the channel state of the frequency channel in the channel state TB in accordance with the order of the receiving frequency channels that the base device 2 will wait for (switch to), and determines the communication channel to use for communication with the base device 2.

[0059] For example, the slave device 1 decides to start communication with the master device 2 at the timing indicated by the arrow A6a in Fig. 6. In this case, the slave device 1 refers to the channel state TB and selects the channel state of the frequency channel "8" which is the same as the reception frequency channel "8" on standby for the master device 2. For example, the slave device 1 selects the channel state of the frequency channel "8" indicated by the dotted line frame A5b in Fig. 5.

[0060] The slave device 1 selects the best channel state (channel state with the smallest interference power) from among the channel states of frequency channel "8" shown in dotted line box A5b in Fig. 5. For example, the slave device 1 selects the channel state shown in dotted line box A5e in Fig. 5. If the channel state of the selected dotted line box A5e satisfies a predetermined channel state (is below a threshold), the slave device 1 communicates with the master device 2 on transmission frequency channel "8" and paired slot "13."

[0061] On the other hand, if the channel state shown in the dotted frame A5e in FIG. 5 does not satisfy the predetermined channel state (is not below the threshold), the slave device 1 selects the channel state of frequency channel "9" shown in the dotted frame A5c in FIG.

[0062] The slave device 1 selects the best channel state (channel state with the smallest interference power) from among the channel states of frequency channel "9" shown in dotted line box A5c in Fig. 5. For example, the slave device 1 selects the channel state shown in dotted line box A5f in Fig. 5. If the channel state of the selected dotted line box A5f satisfies a predetermined channel state (is below a threshold), the slave device 1 communicates with the master device 2 on transmission frequency channel "9" and paired slot "15."

[0063] On the other hand, if the channel state shown in the dotted line box A5f in Fig. 5 does not satisfy the predetermined channel state (is not equal to or less than the threshold), the slave device 1 selects the channel state of frequency channel "0" shown in the dotted line box A5d in Fig. 5. Thereafter, the slave device 1 repeats the above process until it finds a channel state that satisfies the predetermined channel state (a channel state equal to or less than the threshold).

[0064] <Threshold calculation> 7 is a diagram illustrating calculation of the threshold. When the distance between the slave device 1 and the base device 2 is short, the slave device 1 and the base device 2 may be able to communicate even if the channel condition is not good. Therefore, the threshold described above in <Communication channel selection> may be calculated (set) based on the distance between the slave device 1 and the base device 2.

[0065] For example, the threshold value may be a reception level such as a received signal strength indicator (RSSI) in the slave device 1. The reception level such as RSSI may indicate the distance between the slave device 1 and the master device 2.

[0066] The threshold may include a margin. For example, the threshold may be calculated by "NM" as shown in Fig. 7. "N" is the reception level of the wireless signal from the base unit 2 at the slave unit 1. "M" is the margin.

[0067] The margin "M" may be a fixed value or a variable value. If the margin "M" is a variable value, the margin "M" may vary depending on the value of "N." For example, the larger the value of "N," the larger the value of "M" may be.

[0068] <Operation flow> 1. Transmission of control information from the parent unit Fig. 8 is a flowchart showing the operation of transmitting control information in the base unit 2. The base unit 2 executes the process of the flowchart shown in Fig. 8 in each frame, for example.

[0069] The base unit 2 executes an interrupt for a predetermined downstream slot (S1).

[0070] Base unit 2 determines whether the frame number corresponds to the timing for transmitting control information (S2).

[0071] If the frame number is the timing for transmitting control information (YES in S2), the parent device 2 sets the control information in the transmission buffer (S3).

[0072] On the other hand, if the frame number does not correspond to the timing for transmitting control information (NO in S2), the parent device 2 ends the processing of the flowchart.

[0073] The base unit 2 transmits the control information set in the transmission buffer to the slave unit 1 in the slot interrupted in S1 (S4). Then, the base unit 2 ends the processing of this flowchart.

[0074] 2. Control of standby frequency channels in the base station Fig. 9 is a flowchart showing the control operation of the standby frequency channel (receiving frequency channel) in the master unit 2. The master unit 2 executes the process of the flowchart shown in Fig. 9 in each frame, for example.

[0075] The master unit 2 increments the current receiving frequency channel by 1 (S11).

[0076] The base unit 2 determines whether the current reception frequency channel incremented by 1 in S11 is greater than the maximum reception frequency channel (S12). Note that the channel number information included in the control information is the maximum reception frequency channel. For example, if the reception frequency channels of the base unit 2 range from 0 to 9, the maximum reception frequency channel is "9."

[0077] If the current reception frequency channel incremented by 1 in S11 is greater than the maximum reception frequency channel (YES in S12), the master unit 2 sets the current reception frequency channel to "0" (S13).

[0078] On the other hand, if the current reception frequency channel incremented by 1 in S11 is not greater than the maximum reception frequency channel (NO in S12), or if the processing of S13 is completed, the base unit 2 ends the processing of this flowchart.

[0079] 3. Reception of control information in the slave unit Fig. 10 is a flowchart showing the operation of receiving control information in the slave device 1. The slave device 1 executes the process of the flowchart shown in Fig. 10, for example, in each downstream slot.

[0080] The slave unit 1 determines whether or not control information is included in the slot (S21).

[0081] If the slot does not contain control information (NO in S21), the slave unit 1 ends the process of this flowchart.

[0082] On the other hand, if the slot contains control information (YES in S21), the slave unit 1 receives the control information (S22), and then ends the processing of this flowchart.

[0083] 4. Frequency channel control in the slave unit Fig. 11 is a flowchart showing the control operation of the frequency channel in the slave device 1. For example, the slave device 1 executes the process of the flowchart shown in Fig. 11 in each frame. Note that, as described above in <Synchronization of Frequency Channel>, the slave device 1 synchronizes the frequency channel of the slave device 1 with the receiving frequency channel of the master device 2 based on the control information received from the master device 2.

[0084] The slave unit 1 increments the current frequency channel by 1 (S31).

[0085] The slave unit 1 determines whether the current frequency channel incremented by 1 in S31 is greater than the maximum frequency channel (S32). The maximum frequency channel is notified by the master unit 2 using control information.

[0086] If the current frequency channel incremented by 1 in S31 is greater than the maximum frequency channel (YES in S32), the slave unit 1 sets the current frequency channel to "0" (S33).

[0087] On the other hand, if the current frequency channel incremented by 1 in S31 is not greater than the maximum frequency channel (NO in S32), or if the process of S33 is completed, the slave unit 1 ends the process of this flowchart.

[0088] 5. Communication channel selection on the slave unit 12 is a flowchart showing a communication channel selection operation in the slave device 1. For example, when the slave device 1 decides to communicate with the master device 2, the slave device 1 executes the process of the flowchart shown in FIG.

[0089] The slave 1 calculates a threshold value (S41). The threshold value may be "NM" as described above in <Threshold value calculation>.

[0090] The slave unit 1 selects the frequency channel closest to the current standby reception frequency channel of the master unit 2 (S42).

[0091] The slave 1 refers to the channel state TB and selects the channel state with the smallest value (in other words, the best channel state) from the channel states of the frequency channels selected in S42 or S45 described later (S43).

[0092] The slave unit 1 determines whether the channel condition selected in S43 is equal to or less than the threshold calculated in S41 (S44).

[0093] If the channel quality selected in S43 is not equal to or lower than the threshold calculated in S41 (NO in S44), the slave device 1 selects the next frequency channel (S45). The slave device 1 selects frequency channels in the order of the current standby reception frequency channels of the master device 2.

[0094] On the other hand, if the channel state selected in S43 is equal to or lower than the threshold calculated in S41 (YES in S44), the slave device 1 selects the pair of frequency channel and slot of the channel state selected in S43 as the communication channel with the master device 2 (S46).Then, the slave device 1 ends the processing of this flowchart.

[0095] <Summary of the embodiment> As described above, the handset 1 refers to the channel status TB, which indicates the channel status between the handset 1 and the base unit 2, and selects a frequency channel to use for communication with the base unit 2. The handset 1 performs wireless communication based on the DECT system using the selected frequency channel. After deciding to communicate with the base unit 2, the handset 2 refers to the frequency channel in the channel status TB in accordance with the order of the reception frequency channels that the base unit 2 waits for, and selects a frequency channel to use for communication with the base unit 2. This enables the handset 2 to start communication with the base unit 2 quickly.

[0096] For example, after the slave device 2 decides to communicate with the base device 2, the order of the reception frequency channels that the base device 2 waits for is set to "8, 9, 0, 1, 2, ...." In this case, the slave device 1 refers to the frequency channels in the channel state TB in the order of "8, 9, 0, 1, 2, ..." and selects the frequency channel to use for communication with the base device 2. This enables the slave device 2 to start communication with the base device 2 quickly.

[0097] Although the embodiments have been described above with reference to the drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims. It is understood that such modifications or alterations also fall within the technical scope of the present disclosure. Furthermore, the components in the embodiments may be combined in any manner without departing from the spirit of the present disclosure.

[0098] In the above-described embodiments, the notation "... part" used for each component may be replaced with other notations such as "... circuitry," "... assembly," "... device," "... unit," or "... module."

[0099] The present disclosure can be realized by software, hardware, or software linked to hardware. Each functional block used in the description of the above embodiments may be partially or entirely realized as an LSI, which is an integrated circuit, and each process described in the above embodiments may be partially or entirely controlled by a single LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. The LSI may have data input and output. Depending on the degree of integration, the LSI may be called an IC, system LSI, super LSI, or ultra LSI.

[0100] The integrated circuit method is not limited to LSI, but may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, a field programmable gate array (FPGA) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within the LSI, may be used. The present disclosure may be realized as digital processing or analog processing.

[0101] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology may be used to integrate functional blocks. The application of biotechnology, etc. is also a possibility.

[0102] The present disclosure may be implemented in any type of apparatus, device, or system (collectively referred to as a communications apparatus) that has a communications function. The communications apparatus may include a wireless transceiver and processing / control circuitry. The wireless transceiver may include a receiver and a transmitter, or both functions. The wireless transceiver (transmitter and receiver) may include a radio frequency (RF) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or the like. Non-limiting examples of communication devices include telephones (e.g., cell phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine devices, communication-enabled vehicles or mobile transportation (e.g., cars, airplanes, ships), and combinations of the above devices.

[0103] Communications equipment is not limited to portable or mobile equipment, but also includes non-portable or fixed equipment, devices, and systems of any kind, such as smart home devices (such as appliances, lighting equipment, smart meters or metering devices, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0104] A communications apparatus also includes devices such as controllers and sensors connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0105] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these. [Industrial Applicability]

[0106] The present disclosure is useful for communication systems such as mobile phone systems or intercom systems using the DECT system. [Explanation of symbols]

[0107] 1 handset 2 Base unit 11 Control section 11a Channel selection section 11b Channel scan processing unit 12 Radio section 12a Radio transmitter 12b Radio receiver 21 Control section 21a Channel switching section 21b Control information generation unit 22 Radio Section 22a Radio transmitter 22b Radio receiver

Claims

1. a control unit that refers to a table indicating a channel state between the communication terminal and the communication terminal, and selects a frequency channel to be used for communication with the communication terminal; a radio unit that uses the frequency channel to perform radio communication based on a DECT (Digital Enhanced Cordless Telecommunications) system; Equipped with after determining to communicate with the communication partner device, the control unit refers to the frequency channels in the table in accordance with the order of frequency channels awaited by the communication partner device, and selects a frequency channel to be used for communication with the communication partner device; Communication equipment.

2. the control unit selects, as a communication channel for communication with the communication partner device, a slot associated with a slot in which the best channel state of the frequency channels selected in the order satisfies a predetermined channel state, and the selected frequency channel. The communication device according to claim 1 .

3. the channel state is interference power, and the control unit selects, as the slot of the communication channel, a slot associated with a slot in which interference power of the frequency channel selected in the order is the smallest and is equal to or less than a threshold; The communication device according to claim 2 .

4. the control unit determines the threshold value based on a distance between the communication device and the communication partner device. The communication device according to claim 3 .

5. The control unit includes a margin in the threshold value. The communication device according to claim 4.

6. referring to a table showing a channel state with a communication partner device, and selecting a frequency channel to be used for communication with the communication partner device; Using the frequency channel, wireless communication based on the DECT (Digital Enhanced Cordless Telecommunications) system is performed, after determining to communicate with the communication partner device, refer to the frequency channels in the table in the order of the frequency channels on standby for the communication partner device, and select a frequency channel to be used for communication with the communication partner device; Communication method.

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