Relay apparatus and computer-readable recording medium

Even if a relay apparatus such as a mobile router indicates the radio wave reception intensity as low, medium, and high levels, a user using the relay apparatus such as a mobile router cannot recognize that the communication quality is lowered because the radio wave reception intensity is too high. A relay apparatus that relays wireless communication between a communication terminal and a base station is provided, the relay apparatus comprising: a first communication quality acquiring unit that acquires first communication quality of communication with the base station; a first communication quality indicating unit that indicates the first communication quality acquired by the first communication quality acquiring unit; a reception intensity acquiring unit that acquires reception intensity of a radio wave received from the base station; and a reception intensity indicating unit that indicates that the reception intensity acquired by the reception intensity acquiring unit has exceeded a predetermined threshold.

The contents of the following Japanese patent application are incorporated herein by reference: No. 2012-212153 filed on Sep. 26, 2012.

BACKGROUND

1. Technical Field

The present invention relates to a relay apparatus and a computer-readable recording medium.

2. Related Art

A mobile router that acquires radio wave reception intensity separately as low, medium, and high levels is known (for example, Patent Literature 1).

Patent Literature 1: Japanese Patent Application Publication No. 2010-226668

However, even if a relay apparatus such as a mobile router indicates the radio wave reception intensity as low, medium, and high levels, a user who uses the relay apparatus such as a mobile router cannot recognize that the communication quality is lowered because the radio wave reception intensity is too high.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1schematically illustrates the functional configuration of a relay apparatus100. The relay apparatus100relays wireless communication between a base station200and a communication terminal300. The relay apparatus100comprises a first communication unit102, a reception intensity acquiring unit104, a reception intensity indicating unit106, a first communication quality acquiring unit108, a first communication quality indicating unit110, a second communication unit112, a second communication quality acquiring unit114, a second communication quality indicating unit116, an instructing unit118, and a control unit120.

The first communication unit102communicates with the base station200in a first wireless communication mode.

The first wireless communication mode is, for example, the LTE (Long Term Evolution). Also, the first wireless communication mode may be any of the third generation mobile communication mode (3G), the HSDPA (High Speed Downlink Packet Access), and the mobile WiMAX.

The reception intensity acquiring unit104acquires the reception intensity of radio waves received from the base station200. The reception intensity acquiring unit104, for example, measures, as the reception intensity, the RSRP (Reference Signal Received Power) of radio waves received from the base station200.

The reception intensity indicating unit106indicates that the reception intensity acquired by the reception intensity acquiring unit104has exceeded a predetermined threshold. The predetermined threshold may be a threshold at which the communication quality between the relay apparatus100and the base station200lowers because the radio wave intensity of radio waves received from the base station200is too high.

The first communication quality acquiring unit108acquires first communication quality of communication with the base station200. The first communication quality acquiring unit108may measure, as the first communication quality, the communication throughput of communication with the base station200. Also, the first communication quality acquiring unit108may calculate, as the first communication quality, the RSRQ of communication with the base station200(Reference Signal Received Quality). Also, the first communication quality acquiring unit108may calculate, as the first communication quality, the SINR (Signal to Interference and Noise Ratio) of signals received from the base station200.

Also, the first communication quality acquiring unit108may acquire the first communication quality based on the RSRP, the RSRQ, and the SINR. For example, the first communication quality acquiring unit108may acquire, as the first communication quality, a value obtained by weighting respectively and adding together the RSRP, the RSRQ, and the SINR. Furthermore, the first communication quality acquiring unit108may calculate the first communication quality by taking into consideration the degree of interference of radio waves emitted from other equipment.

The first communication quality indicating unit110indicates the first communication quality acquired by the first communication quality acquiring unit108. The first communication quality indicating unit110may indicate to which communication quality level among a plurality of communication quality levels the first communication quality acquired by the first communication quality acquiring unit108corresponds.

The second communication unit112communicates with the communication terminal300in a second wireless communication mode. The second wireless communication mode is, for example, Wi-Fi (registered trademark). The second wireless communication mode may be a wireless LAN other than Wi-Fi, and may be a short-range wireless communication mode such as Bluetooth (registered trademark).

The second communication quality acquiring unit114acquires second communication quality of communication with the communication terminal300. The second communication quality acquiring unit114may measure, as the second communication quality, the signal intensity of signals received from the communication terminal300. Also, the second communication quality acquiring unit114acquires influence of radio waves emitted from another relay apparatus (not illustrated) on the second communication quality. The other relay apparatus may be, for example, a wireless LAN access point. The second communication quality acquiring unit114may measure the signal intensity of signals received from the other relay apparatus. Also, the second communication quality acquiring unit114may measure the signal frequency of signals received from the other relay apparatus. The second communication quality acquiring unit114may acquire influence of radio waves emitted from the other relay apparatus on the second communication quality based on at least any of the measured signal intensity and signal frequency of signals received from the other relay apparatus.

Also, the second communication quality acquiring unit114may measure, as the second communication quality, the communication throughput between the relay apparatus100and the communication terminal300. The second communication quality acquiring unit114may, for example, execute a ping command for the communication terminal300, and analyze a response to the ping command, the data link speed, and the presence/absence of data retransmission in the MAC layer to measure the communication throughput between the relay apparatus100and the communication terminal300.

Also, the second communication quality acquiring unit114may receive the second communication quality from the communication terminal300. For example, the second communication quality acquiring unit114may receive, from the communication terminal300, the second communication quality measured by the communication terminal300during communication with the relay apparatus100.

The second communication quality indicating unit116indicates the second communication quality acquired by the second communication quality acquiring unit114. The second communication quality acquiring unit114may indicate to which communication quality level among a plurality of communication quality levels the second communication quality acquired by the second communication quality acquiring unit114corresponds.

The instructing unit118instructs the reception intensity acquiring unit104to acquire the reception intensity of radio waves received from base station200Also, the instructing unit118instructs the first communication quality acquiring unit108to acquire the first communication quality of communication with the base station200. Also, the instructing unit118instructs the second communication quality acquiring unit114to acquire the second communication quality of communication with the communication terminal300.

The instructing unit118may have one operation button. The instructing unit118may execute the instructions of the reception intensity acquiring unit104, the first communication quality acquiring unit108, and the second communication quality acquiring unit114upon detecting pressing of the operation button.

When pressing of the operation button is detected, the instructing unit118may continue the instructions of the reception intensity acquiring unit104, the first communication quality acquiring unit108, and the second communication quality acquiring unit114for a certain length of time. For example, when the certain length of time is set at three minutes, the acquisition and indication of the reception intensity and communication quality are executed continuously for three minutes.

The operation button may be a toggle button. When pressing of the operation button is detected, the instructing unit118may continuously execute the instructions of the reception intensity acquiring unit104, the first communication quality acquiring unit108, and the second communication quality acquiring unit114, and stop the instructions when pressing of the operation button is detected again. Note that the instructing unit118may have three operation buttons respectively for executing instructions of the reception intensity acquiring unit104, the first communication quality acquiring unit108, and the second communication quality acquiring unit114.

The control unit120controls the first communication unit102, the reception intensity acquiring unit104, the reception intensity indicating unit106, the first communication quality acquiring unit108, the first communication quality indicating unit110, the second communication unit112, the second communication quality acquiring unit114, the second communication quality indicating unit116, and the instructing unit118.

The relay apparatus100may have a plurality of light-emitting units. For example, the relay apparatus100may have an LED indicator for indicating the first communication quality. The first communication quality indicating unit110may indicate the first communication quality by the LED indicator. Also, the relay apparatus100may have an LED indicator for indicating the second communication quality. The second communication quality indicating unit116may indicate the second communication quality by the LED indicator. Also, the relay apparatus100may have an LED for indicating that the reception intensity acquired by the reception intensity acquiring unit104has exceeded a predetermined threshold. The reception intensity indicating unit106may cause the LED to emit light to indicate that the reception intensity has exceeded a predetermined threshold.

Also, the relay apparatus100may have a display unit. The first communication quality indicating unit110may display the first communication quality on the display unit. The first communication quality indicating unit110may display the first communication quality as an indicator on the display unit. Also, the first communication quality indicating unit110may display the first communication quality as numerical data on the display unit.

The second communication quality indicating unit116may display the second communication quality on the display unit. The second communication quality indicating unit116may display the second communication quality as an indicator on the display unit. Also, the second communication quality indicating unit116may display the second communication quality as numerical data on the display unit.

Also, the reception intensity indicating unit106may display on the display unit that the reception intensity acquired by the reception intensity acquiring unit104has exceeded a predetermined threshold. The reception intensity indicating unit106may display, as text data on the display unit, that the reception intensity has exceeded a predetermined threshold. Also, the reception intensity indicating unit106may display on the display unit an object that indicates that the reception intensity has exceeded a predetermined threshold.

The base station200comprises a base station communication unit202that communicates with the first communication unit102of the relay apparatus100. The base station200may be an LTE base station, and may be any of 3G, HSDPA and mobile WiMAX base stations.

The communication terminal300comprises a terminal communication unit302to communicate with the second communication unit112of the relay apparatus100, and a display unit304. The communication terminal300is equipment capable of communicating with the relay apparatus100, and may be, for example, a smartphone, a tablet terminal, a PC terminal, or the like.

The first communication quality indicating unit110may indicate the relay apparatus100user of the first communication quality by displaying the first communication quality on the display unit304. Also, the second communication quality indicating unit116may indicate the second communication quality by displaying the second communication quality on the display unit304. Also, the reception intensity indicating unit106may display, on the display unit304, that the reception intensity acquired by the reception intensity acquiring unit104has exceeded a predetermined threshold.

FIG. 2schematically illustrates variation in reception intensity depending of locations where a home-installation type relay apparatus100is arranged. As illustrated inFIG. 2, it has been known that the reception intensity becomes high at locations, such as a window side on a second floor, where there are few blocking objects that block radio waves, and the reception intensity becomes low at locations, such as a basement, where there are many blocking objects. Accordingly, in general, the relay apparatus100is in many cases arranged at locations where there are as few blocking objects as possible so as to improve the communication quality by increasing the reception intensity. However, increasing the radio wave reception intensity does not necessarily improve the communication quality.

FIG. 3illustrates experimental results obtained by actually measuring the RSRP of radio waves received by the relay apparatus100from the base station200, and the communication throughput between the relay apparatus100and the base station200. The horizontal axis indicates the RSRP, and the vertical axis indicates the communication throughput.

As illustrated inFIG. 3, until the value of RSRP increases to around −68 dBm, higher RSRP leads to higher communication throughput. However, after the value of RSRP exceeds around −68 dBm, higher RSRP leads to lower communication throughput. In this manner, when the reception intensity of radio waves received from the base station200is too high to cause saturation, the communication throughput lowers.

To cope with this, the relay apparatus100according to the present embodiment indicates the communication quality of communication with the base station200and also indicates that the reception intensity of radio waves received from the base station200has exceeded a predetermined threshold. The predetermined threshold may be, for example, −65 dBm. Also, the predetermined threshold may be, for example, set by a user who has checked the experimental results as illustrated inFIG. 3.

FIG. 4schematically illustrates one example of the external appearance of the relay apparatus100. The relay apparatus100illustrated inFIG. 4comprises, on its side surface, the instructing unit118having an operation button, a plurality of first communication quality light-emitting units130, and a reception intensity light-emitting unit140. The plurality of first communication quality light-emitting units130and the reception intensity light-emitting unit140are LEDs for example.

The plurality of first communication quality light-emitting units130correspond to respective ones of a plurality of communication quality levels of communication with the base station200. The plurality of first communication quality light-emitting units130may be arrayed in the order of corresponding communication quality levels.FIG. 4illustrates an example in which the plurality of first communication quality light-emitting units130are arrayed such that the leftmost one, as seen when looking at the figure, corresponds to the lowest communication quality level, and the communication quality level increases as the position of a first communication quality light-emitting unit130shifts rightward as seen when looking at the figure.

The first communication quality indicating unit110may indicate the first communication quality by causing a first communication quality light-emitting unit130, among the plurality of first communication quality light-emitting units130, that corresponds to the first communication quality acquired by the first communication quality acquiring unit108to emit light. The first communication quality indicating unit110may cause, in addition to the first communication quality light-emitting unit130that corresponds to the first communication quality, first communication quality light-emitting units130that correspond to communication quality that is lower than the first communication quality to emit light. For example, when the first communication quality corresponds to the fourth first communication quality light-emitting unit130as counted from the left end, the first communication quality indicating unit110may cause all the four, first to fourth, first communication quality light-emitting units130as counted from the left end to emit light.

The plurality of first communication quality light-emitting units130may emit light of different colors depending on corresponding communication quality levels. For example, wavelengths of light emitted by the plurality of first communication quality light-emitting units130decrease according to the order of the plurality of communication quality levels. As a specific example, the leftmost first communication quality light-emitting unit130may emit red light, the next adjacent two first communication quality light-emitting units130may emit orange light, the next adjacent three first communication quality light-emitting units130may emit yellow, the next adjacent four first communication quality light-emitting units130may emit green light, and the next adjacent two first communication quality light-emitting units130may emit blue light.

Thereby, it is possible to allow the relay apparatus100user to intuitively recognize differences of the communication quality. Note that the plurality of first communication quality light-emitting units130may respectively have light sources, and the plurality of first communication quality light-emitting units130may share one light source.

The reception intensity light-emitting unit140may be arranged at any position on a surface of the relay apparatus100, but is preferably arranged in the vicinity of the plurality of first communication quality light-emitting units130so as to be within the visual field of a user together with the plurality of first communication quality light-emitting units130. The reception intensity light-emitting unit140may be arranged at a position adjacent to the first communication quality light-emitting unit130that corresponds to the highest communication quality level among the plurality of first communication quality light-emitting units130. The reception intensity indicating unit106may indicate that the reception intensity acquired by the reception intensity acquiring unit104has exceeded a predetermined threshold by causing the reception intensity light-emitting unit140to emit light when the reception intensity has exceeded the predetermined threshold.

The relay apparatus100user can arrange the relay apparatus100at an appropriate position where the reception intensity is not too high, but the communication quality is high, by arranging the relay apparatus100so as not to cause the reception intensity light-emitting unit140to emit light, but to cause a first communication quality light-emitting unit130that corresponds to higher communication quality to emit light. Also, when the reception intensity light-emitting unit140happens to emit light, the relay apparatus100user can recognize that, by moving the relay apparatus100to a position where the reception intensity of radio waves from the base station200become lower, the communication quality can be improved.

FIG. 5illustrates one example of a flowchart of an indication process by the relay apparatus100. The flowchart illustrated inFIG. 5starts when an instruction from the instructing unit118is executed. At a step S502, the reception intensity acquiring unit104acquires the reception intensity of radio waves received from the base station200.

At a step S504, the first communication quality acquiring unit108acquires the first communication quality of communication with the base station200. At a step S506, the first communication quality indicating unit110causes the first communication quality light-emitting unit130to emit light to indicate the first communication quality acquired at the step S504.

At a step S508, the control unit120judges whether there is the communication terminal300that has established communication with the relay apparatus100. If it is judged by the control unit120that there is the communication terminal300that has established communication, the process proceeds to a step S510, and if not, the process proceeds to a step S514.

At the step S510, the second communication quality acquiring unit114acquires the second communication quality of communication with the communication terminal300. At a step S512, the second communication quality indicating unit116causes a second communication quality light-emitting unit150to emit light to indicate the second communication quality acquired at the step S510.

At the step S514, the control unit120judges whether the reception intensity acquired at the step S502has exceeded a predetermined threshold. If it is judged by the control unit120that the reception intensity has exceeded the predetermined threshold, the process proceeds to a step S516, and if not, the process proceeds to a step S518. At the step S516, the reception intensity indicating unit106causes the reception intensity light-emitting unit140to emit light to indicate that the reception intensity has exceeded the predetermined threshold.

At the step S518, the control unit120judges whether a predetermined certain length of time has elapsed since an operation button was pressed. If it is judged by the control unit120that the certain length of time has not elapsed, the process returns to the step S502, and if it is judged the certain length of time has elapsed, the process ends.

As described above, the relay apparatus100continuously indicates the first communication quality and the second communication quality until the certain length of time elapses since the operation button is pressed. If the reception intensity of radio waves from the base station200exceeds the predetermined threshold when the first communication quality and the second communication quality are continuously being indicated, the reception intensity light-emitting unit140is caused to emit light to indicate that the reception intensity is too high.

FIG. 6schematically illustrates another array example of the plurality of first communication quality light-emitting units130and the reception intensity light-emitting unit140. As illustrated inFIG. 6, the plurality of first communication quality light-emitting units130and the reception intensity light-emitting unit140may be arrayed along the shape of a line graph that indicates relationship between the reception intensity of signals received from the base station200and the communication throughput of communication with the base station200. The plurality of first communication quality light-emitting units130are arrayed such that the leftmost one, as seen when looking at the figure, corresponds to the lowest communication quality level, and the communication quality level increases as the position of a first communication quality light-emitting unit130shifts rightward as seen when looking at the figure.

Thereby, it is possible to cause the relay apparatus100user to recognize intuitively what degree of communication throughput can be expected based on the position of a first communication quality light-emitting unit130that is emitting light. Also, it is possible to cause the relay apparatus100user to recognize intuitively, when the reception intensity light-emitting unit140emits light, that the communication quality is lowered because the reception intensity is too high.

FIG. 7schematically illustrates another array example of the plurality of first communication quality light-emitting units130and the reception intensity light-emitting unit140. As illustrated inFIG. 7, the position where a respective one of the plurality of first communication quality light-emitting units130is arranged may be higher as the position shifts rightward. Also, the reception intensity light-emitting unit140may be arranged on the right side of and lower than the rightmost first communication quality light-emitting unit130among the plurality of first communication quality light-emitting units130.

Thereby, it is possible to cause the relay apparatus100user to recognize intuitively what degree of communication quality can be expected based on the position of a first communication quality light-emitting unit130that is emitting light. Also, it is possible to cause the relay apparatus100user to recognize intuitively, when the reception intensity light-emitting unit140emits light, that the communication quality is lowered because the reception intensity is too high.

FIG. 8schematically illustrates a display example of the display unit304of the communication terminal300. On the display unit304, a plurality of first communication quality objects320, reception intensity information330, a second communication quality object340, and a comment350are displayed.

The first communication quality indicating unit110may display, on the display unit304, a first communication quality object320, among the plurality of first communication quality objects320that correspond to respective ones of a plurality of communication quality levels, that corresponds to the first communication quality between the relay apparatus100and the base station200. The first communication quality indicating unit110may display, on the display unit304, only the first communication quality object320that corresponds to the first communication quality between the relay apparatus100and the base station200. Also, the first communication quality indicating unit110may display, on the display unit304in addition to the first communication quality object320that corresponds to the first communication quality between the relay apparatus100and the base station200, first communication quality objects320that correspond to communication quality that is lower than the first communication quality.FIG. 8illustrates an example in which when the first communication quality is at the level 10 among twelve levels, first communication quality objects320that correspond to the levels 1 to 10, respectively, are displayed on the display unit304.

The reception intensity indicating unit106displays the reception intensity information330on the display unit304when the reception intensity acquired by the reception intensity acquiring unit104has exceeded a predetermined threshold. Also, the reception intensity indicating unit106may display the reception intensity information330on the display unit304when a length of time during which the reception intensity acquired by the reception intensity acquiring unit104has exceeded a predetermined threshold has exceeded a predetermined length of time per unit time. Thereby, it is possible to prevent the reception intensity information330from being displayed on the display unit304when the reception intensity has exceeded a predetermined threshold momentarily. The reception intensity information330may have a shape that is identical with the first communication quality object320or may have a different shape.FIG. 8illustrates a display example in which the reception intensity information330and the first communication quality object320have identical shapes.

The reception intensity indicating unit106may display the comment350on the display unit304in addition to the reception intensity information330when the reception intensity of radio waves received by the relay apparatus100from the base station200has exceeded a predetermined threshold. The comment350may be a message for indicating that the reception intensity is too high. Also, the comment350may be a message including advice to reduce the reception intensity of the relay apparatus100. For example, the comment350may be a message to recommend moving the relay apparatus away from a window.

The second communication quality indicating unit116displays the second communication quality between the relay apparatus100and the communication terminal300on the display unit304. The second communication quality indicating unit116may display the second communication quality object340on the display unit304as the second communication quality. Also, the second communication quality indicating unit116may display the comment350about the second communication quality on the display unit304.FIG. 8illustrates a display example of the second communication quality object340when the second communication quality is at the level 3 among five levels.

Note that although an example in which the reception intensity indicating unit106displays the comment350on the display unit304was explained with reference toFIG. 8, the first communication quality indicating unit110may display the comment350on the display unit304. When the first communication quality is calculated based on a plurality of values such as RSRP, RSRQ, and SINR, and the first communication quality is low, the first communication quality indicating unit110may display, as the comment350on the display unit304, because which value among the plurality of values is low the first communication quality is lowered. For example, when the first communication quality is half of or lower than the plurality of communication quality levels, the first communication quality indicating unit110may display, as the comment350on the display unit304, because which value among the plurality of values the first communication quality is lowered.

FIG. 9schematically illustrates the relay apparatus100comprising a movable antenna cover410. The antenna cover410is made of a blocking member that blocks radio waves emitted from the base station200. In the example illustrated inFIG. 9, the relay apparatus100has a built-in antenna, and depending on the position of the antenna cover410, the degree of blocking radio waves from reaching the built-in antenna changes.

For example, when the reception intensity indicating unit106indicates that the reception intensity has exceeded a predetermined threshold, the relay apparatus100user can adjust the reception intensity by moving the antenna cover410instead of moving the relay apparatus100. That is, by providing the antenna cover410to the relay apparatus100, the communication quality can be improved more easily.

FIG. 10illustrates one example of the hardware construction of the relay apparatus100. The relay apparatus100comprises a CPU peripheral unit that has a CPU504and a RAM506that are interconnected by a host controller502, and an input/output unit that has a communication interface510, an LED control unit516, and an operation button524that are connected to the host controller502by an input/output controller508.

The host controller502connects the RAM506and the CPU504that accesses the RAM506at high transfer rate. The CPU504operates based on a program stored in the RAM506, and controls each unit. The input/output controller508connects the host controller502, the communication interface510, the LED control unit516, and the operation button524.

The communication interface510communicates with the base station200via an antenna512. Also, the communication interface510communicates with the communication terminal300via an antenna514. That is, the antenna512may be one example of the first communication unit102. Also, the antenna514may be one example of the second communication unit112.

The LED control unit516controls a first LED518, a second LED520, and a third LED522. The first LED518may be one example of the first communication quality light-emitting unit130. The second LED520may be one example of the reception intensity light-emitting unit140. The third LED522may be one example of the second communication quality light-emitting unit150. The operation button524may be one example of an operation button provided to the instructing unit118.

The program installed in and run by the relay apparatus100may act on the CPU504and the like to cause the relay apparatus100to function as the first communication unit102, the reception intensity acquiring unit104, the reception intensity indicating unit106, the first communication quality acquiring unit108, the first communication quality indicating unit110, the second communication unit112, the second communication quality acquiring unit114, the second communication quality indicating unit116, the instructing unit118, the control unit120, the first communication quality light-emitting unit130, the reception intensity light-emitting unit140, and the second communication quality light-emitting unit150that were explained with reference toFIGS. 1 to 9.

Note that although in the present embodiment, an example in which the relay apparatus100comprises the second communication quality acquiring unit114and the second communication quality indicating unit116was explained, the relay apparatus100may not comprise the second communication quality acquiring unit114and the second communication quality indicating unit116.

Also, in the present embodiment, an example in which the reception intensity indicating unit106indicates that the reception intensity has exceeded a predetermined threshold by using the reception intensity light-emitting unit140, or the display unit provided to the relay apparatus100or the communication terminal300was explained. However, the manner of indication is not limited thereto. For example, the relay apparatus100may indicate that the reception intensity acquired by the reception intensity acquiring unit104has exceeded a predetermined threshold by outputting sound such as a beep when the reception intensity has exceeded the predetermined threshold. Thereby, it is possible to allow a user to recognize that the reception intensity is too high even if the user is not gazing at the relay apparatus100.

The relay apparatus100may use light-emission of the reception intensity light-emitting unit140, display on the display unit, and sound output in combination. Also, the relay apparatus100may comprise any one of the reception intensity light-emitting unit140, the display unit, and a sound output unit. By using light-emission of the reception intensity light-emitting unit140, display on the display unit, and sound output in combination, it is possible to allow a user to surely recognize that the reception intensity is too high. Also, by providing any one of the reception intensity light-emitting unit140, the display unit, and the sound output unit, the number of components can be reduced.

Also, the relay apparatus100may comprise an operation button that can emit light, instead of the reception intensity light-emitting unit140. For example, the operation button is not caused to emit light when the reception intensity has fallen below the predetermined threshold, but that the reception intensity acquired by the reception intensity acquiring unit104has exceeded a predetermined threshold may be indicated by causing the operation button to emit light when the reception intensity has exceeded the threshold. Thereby, it becomes unnecessary to provide the reception intensity light-emitting unit140, and the number of components can be reduced.