Receiving device, transmitting device, communication system

Abstract

We provide technology to reduce power consumption. [Solution] The receiving device 200 includes a demodulation unit 222, a measurement unit 212, a determination unit 216, and a control unit 218. The demodulation unit 222 demodulates the radio signal received by the receiving unit 210. The measurement unit 212 measures the intensity value of the radio signal received by the receiving unit 210. The determination unit 216 determines whether the intensity value measured by the measurement unit 212 satisfies the conditions. Based on the determination result from the determination unit 216, the control unit 218 sets the demodulation unit 222 to either a first mode in which the demodulation unit 222 is stopped, or a second mode in which the demodulation unit 222 is operated.

Description

Technical Field

[0001] The present invention relates to communication technology, and particularly to a receiving device, a transmitting device, and a communication system that perform wireless communication.

Background Art

[0002] In battery-powered wireless devices, low power consumption is required. To achieve low power consumption, the wireless device intermittently activates to determine the presence or absence of a signal from the received radio wave intensity, and returns to the standby state when it determines that there is no signal. On the other hand, when it determines that there is a signal, the wireless device starts a data reception operation and continues the data reception operation when a specific signal is detected, but returns to the standby state when the specific signal is not detected. Also, the period for determining the presence or absence of a signal from the received radio wave intensity is optimized (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When it is determined that there is a signal from the received radio wave intensity but a specific signal is not detected, a data reception operation (demodulation) must be performed even though the signal is not addressed to the own device. Power consumption increases due to such a data reception operation (demodulation).

[0005] The present invention has been made in view of such a situation, and an object thereof is to provide a technique for reducing power consumption.

Means for Solving the Problems

[0006] To solve the above problems, a receiving device according to one aspect of the present invention includes a demodulation unit for demodulating a radio signal, a measurement unit for measuring the intensity value of the radio signal, a determination unit for determining whether the intensity value measured by the measurement unit satisfies a condition, and a control unit for setting the demodulation unit to either a first mode for stopping the demodulation unit or a second mode for operating the demodulation unit, based on the determination result in the determination unit. The control unit sets the demodulation unit to the first mode, where the amplitude fluctuation pattern of the radio signal is assigned to each receiving device, and the condition in the determination unit is that the amplitude fluctuation pattern measured by the measurement unit corresponds to the amplitude fluctuation pattern assigned to this receiving device. When the control unit determines that the condition is met, it changes the demodulation unit from the first mode to the second mode.

[0007] Another aspect of the present invention is a transmitting device. This device comprises an amplitude variation unit that varies the amplitude of a radio signal over time, and a transmitting unit that transmits the radio signal whose amplitude has been varied over time by the amplitude variation unit. The amplitude variation pattern in the amplitude variation unit is assigned to each receiving device, and the amplitude variation unit uses the amplitude variation pattern assigned to the receiving device that is the destination of the radio signal.

[0008] A further aspect of the present invention is a communication system. This communication system includes a transmitting device comprising: a modulation unit that generates a radio signal by performing constant amplitude modulation; an amplitude variation unit that varies the amplitude of the radio signal generated in the modulation unit over time; and a transmitting unit that transmits the radio signal whose amplitude has been varied over time in the amplitude variation unit; and a receiving device comprising: a receiving unit that receives a radio signal; a demodulation unit that demodulates the radio signal received in the receiving unit; a measurement unit that measures the intensity value of the radio signal received in the receiving unit; a determination unit that determines whether the intensity value measured in the measurement unit satisfies a condition; and a control unit that sets the demodulation unit to either a first mode that stops the demodulation unit or a second mode that operates the demodulation unit based on the determination result in the determination unit. In the transmitting device, the amplitude variation pattern in the amplitude variation unit is assigned to each receiving device. The amplitude variation unit uses the amplitude variation pattern assigned to the receiving device that is the destination of the wireless signal. In the receiving device, the control unit sets the demodulation unit to the first mode. The condition in the determination unit is that the variation pattern of the intensity value measured in the measurement unit corresponds to the amplitude variation pattern assigned to this receiving device. When the control unit determines that the condition is met, it changes the demodulation unit from the first mode to the second mode.

[0009] Furthermore, any combination of the above components, as well as conversions of the expression of the present invention between methods, apparatus, systems, recording media, computer programs, etc., are also valid embodiments of the present invention. [Effects of the Invention]

[0010] According to the present invention, power consumption can be reduced. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows the configuration of the communication system according to the embodiment. [Figure 2] This diagram shows the configuration of the transmitting device shown in Figure 1. [Figure 3] Figures 3(a) and 3(b) show the signals processed in the transmitter shown in Figure 2. [Figure 4] Figures 4(a) and 4(b) show the signals processed in the transmitter shown in Figure 2. [Figure 5] Figures 5(a)-(d) show the signals processed in the transmitter shown in Figure 2. [Figure 6] Figures 6(a) and 6(b) show the signals processed in the transmitter shown in Figure 2. [Figure 7] Figures 7(a)-(b) show the signals processed in the transmitter shown in Figure 2. [Figure 8] This diagram shows the configuration of the receiving device shown in Figure 1. [Figure 9] Figure 8 is a flowchart showing the processing procedure by the receiving device. [Modes for carrying out the invention]

[0012] Before describing this embodiment in detail, let's first outline it. This embodiment relates to a communication system in which wireless communication is performed between a transmitting device and a receiving device. The transmitting device transmits a wireless signal containing data or voice information. Conventional receiving devices, upon receiving a wireless signal, measure the strength value of the received wireless signal (RSSI (Received Signal Strength Indicator) value). If the strength value is below a threshold, the receiving device determines that it has not received a wireless signal and enters power-saving mode. In power-saving mode, the receiving device stops demodulating the wireless signal. On the other hand, if the strength value is above the threshold, it determines that it has received a wireless signal and enters normal mode. In normal mode, the receiving device starts demodulating the wireless signal. Furthermore, the receiving device outputs data or voice information as a result of the demodulation process. The wireless signal contains information specifying the destination (individually or in a group) (hereinafter referred to as "destination information"), and the receiving device obtains the destination information as a result of the demodulation process. If the destination information does not match its own device, it does not output voice.

[0013] That is, even when the destination information does not correspond to the self-device, if the intensity value becomes equal to or greater than the threshold value, the receiving device in the power-saving mode temporarily switches to the normal mode. If the destination information in the result of the demodulation process does not correspond to the self-device, it returns to the power-saving mode. Therefore, even when the destination information does not correspond to the self-device, it is necessary to execute the demodulation process, and the power consumption increases. When the receiving device is battery-powered, low power consumption is required.

[0014] The transmitting device according to the present embodiment transmits while varying the amplitude of the radio signal over time. The pattern of the amplitude variation is assigned to each receiving device. When the intensity value is equal to or greater than the threshold value and the pattern of the intensity value variation corresponds to the pattern of the amplitude variation assigned to the self-device, the receiving device enters the normal mode. Since it is only necessary to confirm whether the pattern of the intensity value variation corresponds to the pattern of the amplitude variation assigned to the self-device, the demodulation process for confirming the destination information is unnecessary, and the power-saving mode can be continued. As a result, low power consumption is achieved.

[0015] FIG. 1 shows the configuration of the communication system 1000. The communication system 1000 includes a transmitting device 100 and a receiving device 200. Both the transmitting device 100 and the receiving device 200 are radio devices. In the communication system 1000, two radio devices perform two-way radio communication. Here, for the sake of simplicity, the one-way radio communication from the transmitting device 100 to the receiving device 200 is the subject of the description. The receiving device 200 is battery-powered. The transmitting device 100 may also be battery-powered.

[0016] The transmitting device 100 transmits a radio signal including data or voice information from the antenna 150 to the receiving device 200. When the receiving device 200 receives the radio signal from the transmitting device 100 by the antenna 250, it outputs data or voice information by demodulating the radio signal. The receiving device 200 may output the reproduced voice of the voice information.

[0017] The battery-powered receiving device 200 is required to reduce power consumption. Therefore, in the receiving device 200, a normal mode (second mode) for executing demodulation processing and output processing and a power-saving mode (first mode) for stopping demodulation processing and output processing can be switched. The receiving device 200 executes the normal mode when receiving a radio signal addressed to itself. On the other hand, the receiving device 200 executes the power-saving mode for power consumption reduction when not receiving a radio signal addressed to itself. The receiving device 200 according to the present embodiment further reduces power consumption by checking whether the received radio signal is addressed to itself while in the power-saving mode.

[0018] FIG. 2 shows the configuration of the transmitting device 100. The transmitting device 100 includes an input unit 110, a modulation unit 112, a storage unit 114, a control unit 116, an amplitude variation unit 118, a transmitting unit 120, and an antenna 150. The modulation unit 112, the control unit 116, and the amplitude variation unit 118 are configured by, for example, a dedicated circuit or a DSP (Digital Signal Processor).

[0019] The input unit 110 receives data or voice information to be transmitted. The input unit 110 also receives destination information of the data or voice information. The input unit 110 is, for example, a microphone that picks up sound and outputs an audio signal, a touch panel that receives a user's operation, a button, a switch, an interface terminal to which an external device that outputs various signals is connected to receive a data signal, etc. The input unit 110 outputs data or voice information to the modulation unit 112 and outputs destination information to the control unit 116.

[0020] The modulation unit 112 receives data or voice information from the input unit 110 and generates a radio signal by performing modulation on the data or voice information. For modulation, constant-amplitude modulation, for example, frequency modulation, is used. The modulation unit 112 outputs the radio signal to the amplitude variation unit 118.

[0021] The control unit 116 receives destination information from the input unit 110. The storage unit 114 stores the correspondence between destination information that can be received by the control unit 116 and the amplitude fluctuation pattern of the wireless signal. The storage unit 114 includes, for example, at least one of the following: RAM (Random Access Memory), main memory such as ROM (Read Only Memory), and external storage such as HDD (Hard Disk Drive). Here, the amplitude fluctuation pattern of the wireless signal is assigned differently for each receiving device 200. The control unit 116 outputs the amplitude fluctuation pattern corresponding to the received destination information to the amplitude fluctuation unit 118. If the destination information includes multiple different receiving devices 200, the amplitude fluctuation patterns corresponding to each different receiving device 200 may be combined and output to the amplitude fluctuation unit 118.

[0022] The amplitude variation unit 118 receives a wireless signal from the modulation unit 112 and an amplitude variation pattern from the control unit 116. The amplitude variation unit 118 uses the amplitude variation pattern assigned to the receiving device 200, which is the destination of the wireless signal, to vary the amplitude of the wireless signal over time.

[0023] Figures 3(a) and 3(b) show the signals processed by the transmitter 100. In these figures, the horizontal axis represents time and the vertical axis represents amplitude. Figure 3(a) shows the amplitude variation pattern. Here, as an example, it has a sinusoidal shape. Figure 3(b) shows a radio signal whose amplitude is varied over time using the amplitude variation pattern shown in Figure 3(a).

[0024] Figures 4(a) and 4(b) show the signals processed by the transmitter 100. In these figures, the horizontal axis represents time and the vertical axis represents amplitude. Figure 4(a) shows the amplitude variation pattern. This has a sinusoidal shape, similar to Figure 3(a), but has a different period. Therefore, Figures 3(a) and 4(a) are different patterns. Figure 4(b) shows a radio signal with the amplitude varied over time, following the amplitude variation pattern of Figure 4(a). The destination of the radio signal in Figure 4(b) is different from the destination of the radio signal in Figure 4(a).

[0025] Figures 5(a)-(d) show signals processed by the transmitter 100. In these figures, the horizontal axis represents time and the vertical axis represents amplitude. Here, we assume a case where a wireless signal is simultaneously transmitted to two receivers 200, for example, a first receiver 200 and a second receiver 200. Figure 5(a) shows the amplitude variation pattern for the first receiver 200, and is shown in the same way as Figure 3(a). Figure 5(b) shows the amplitude variation pattern for the second receiver 200, and is shown in the same way as Figure 4(a). Figure 5(c) shows the amplitude variation pattern obtained by combining the amplitude variation pattern for the first receiver 200 and the amplitude variation pattern for the second receiver 200. This combination is performed in the control unit 116. Figure 5(d) shows a wireless signal whose amplitude is varied over time according to the amplitude variation pattern in Figure 5(c).

[0026] Figures 6(a) and 6(b) show the signals processed by the transmitter 100. In these figures, the horizontal axis represents time and the vertical axis represents amplitude. Figure 6(a) shows the amplitude variation pattern. While the previous patterns had a sinusoidal shape, the pattern in Figure 6(a) shows discrete waves with one period. Figure 6(b) shows a radio signal with amplitude varying over time using the amplitude variation pattern shown in Figure 6(a).

[0027] Figures 7(a) and 7(b) show the signals processed by the transmitter 100. In these figures, the horizontal axis represents time and the vertical axis represents amplitude. Figure 7(a) shows the amplitude variation pattern. Figure 7(a) shows a pattern similar to that of Figure 6(a), but the interval between the discrete appearance of one-period waves is different from that of Figure 6(a). Figure 7(b) shows a radio signal with amplitude varied over time using the amplitude variation pattern of Figure 7(a). Return to Figure 2.

[0028] The transmitting unit 120 transmits a radio signal, whose amplitude has been varied over time in the amplitude variation unit 118, as a radio wave from the antenna 150.

[0029] Figure 8 shows the configuration of the receiving device 200. The receiving device 200 includes a receiving unit 210, a measuring unit 212, a storage unit 214, a determination unit 216, a control unit 218, and a processing unit 220. The processing unit 220 includes a demodulation unit 222 and an output unit 224. The measuring unit 212, the determination unit 216, the control unit 218, and the processing unit 220 are configured, for example, by dedicated circuits or DSPs (Digital Signal Processors).

[0030] The receiving unit 210 receives a wireless signal from the transmitting device 100 via the antenna 250. As described above, the wireless signal is modulated with a constant amplitude, and the amplitude fluctuates over time. Furthermore, the constant amplitude modulation in the wireless signal is frequency modulation, and a pattern of amplitude fluctuation in the wireless signal is assigned to each receiving device 200. The receiving unit 210 outputs the received wireless signal to the measuring unit 212 and the processing unit 220.

[0031] The measurement unit 212 measures the intensity value (received intensity value) of the wireless signal received by the receiving unit 210. An example of an intensity value is the RSSI value. Since known techniques can be used to measure the intensity value, a detailed explanation is omitted here. The measurement unit 212 outputs the sequentially measured intensity values ​​to the determination unit 216.

[0032] The determination unit 216 receives the intensity value from the measurement unit 212. The determination unit 216 compares the intensity value with a threshold value stored in the storage unit 214 and determines that a wireless signal has been received if the intensity value is equal to or greater than the threshold value. On the other hand, the determination unit 216 determines that a wireless signal has not been received if the intensity value is less than the threshold value.

[0033] Here, the storage unit 214 stores the amplitude fluctuation pattern assigned to the receiving device 200. When the determination unit 216 determines that a wireless signal has been received, it determines whether the intensity value fluctuation pattern measured by the measurement unit 212 corresponds to the fluctuation pattern stored in the storage unit 214. Specifically, the determination unit 216 calculates the difference between the intensity value fluctuation pattern measured by the measurement unit 212 and the fluctuation pattern stored in the storage unit 214 over a certain period of time, and determines that there is a correspondence if the difference is less than or equal to a reference value. On the other hand, the determination unit 216 determines that there is no correspondence if the difference is greater than or equal to the reference value. Alternatively, if the intensity value measured by the measurement unit 212 is a fluctuation pattern that combines multiple destinations, the determination unit 216 is configured with a filter that extracts the amplitude fluctuation pattern assigned to the receiving device 200. In this case, it is determined that there is a correspondence if the output value of the filter is greater than or equal to a predetermined value. If there is a correspondence, it corresponds to the wireless signal being addressed to the device itself. The determination unit 216 outputs the determination result to the control unit 218. The result indicates one of the following: no wireless signal was received, a wireless signal addressed to the device was received, or a wireless signal not addressed to the device was received.

[0034] The control unit 218 receives the determination result from the determination unit 216. If the determination result is either that no wireless signal has been received, or that a wireless signal not addressed to the device has been received, the control unit 218 selects a power-saving mode (first mode) that stops the processing unit 220. On the other hand, if the determination result is that a wireless signal addressed to the device has been received, the control unit 218 selects a normal mode (second mode) that operates the processing unit 220.

[0035] When the control unit 218 selects the power-saving mode (first mode), it sets the processing unit 220 to power-saving mode (first mode). This is equivalent to stopping the processing unit 220. On the other hand, when the control unit 218 selects the normal mode (second mode), it sets the processing unit 220 to normal mode (second mode). This is equivalent to operating the processing unit 220. Therefore, when the situation changes from not receiving a wireless signal to receiving a wireless signal addressed to the device, the control unit 218 changes from power-saving mode (first mode) to normal mode (second mode). As a result, the stopped processing unit 220 starts operating.

[0036] The demodulation unit 222 and the output unit 224 operate when the control unit 218 sets them to normal mode (second mode). The demodulation unit 222 receives a radio signal from the receiving unit 210 and demodulates the radio signal. By demodulating the radio signal, the demodulation unit 222 acquires data or audio information. The demodulation unit 222 outputs the data or audio information to the output unit 224.

[0037] The output unit 224 receives data or audio information from the demodulation unit 222. If the output unit 224 receives data, it outputs the data externally or displays the data content on a display (not shown). If the output unit 224 receives audio information, it plays the audio from the audio information and outputs it from a speaker (not shown).

[0038] This configuration can be implemented in hardware terms using the CPU, memory, and other LSIs of any computer, and in software terms using programs loaded into memory, but here we are depicting the functional blocks that are realized through the cooperation of these components. Therefore, it will be understood by those skilled in the art that these functional blocks can be implemented in various ways using hardware alone, software alone, or a combination of both.

[0039] Figure 9 is a flowchart showing the processing procedure by the receiving device 200. If the received signal strength value measured by the measurement unit 212 is above the threshold (Y in S10) and the pattern of fluctuation in the received signal strength value is the assigned fluctuation pattern (Y in S12), the control unit 218 sets the processing unit 220 to normal mode (S14). If the received signal strength value measured by the measurement unit 212 is not above the threshold (N in S10), or if the pattern of fluctuation in the received signal strength value is not the assigned fluctuation pattern (N in S12), the control unit 218 sets the processing unit 220 to power saving mode (S16).

[0040] According to this embodiment, the processing unit is activated when the pattern of fluctuation in the measured intensity value of the wireless signal corresponds to the amplitude fluctuation pattern assigned to this receiving device, and the processing unit is stopped otherwise. This avoids activating the processing unit when a wireless signal not intended for this receiving device is received. Furthermore, since the processing unit is not activated when a wireless signal not intended for this receiving device is received, power consumption can be reduced. In addition, since the amplitude fluctuation pattern of the wireless signal is assigned to each receiving device, it is possible to distinguish between wireless signals intended for this receiving device and wireless signals not intended for this receiving device. Furthermore, since constant amplitude modulation is frequency modulation, the amplitude fluctuation pattern can be used to identify the receiving device.

[0041] Furthermore, by using an amplitude variation pattern assigned to the receiving device that is the destination of the wireless signal, the amplitude of the wireless signal is varied over time, so the destination of the wireless signal can be communicated to the receiving device without demodulation. In addition, since the destination of the wireless signal can be communicated to the receiving device without demodulation, the power consumption of the receiving device can be reduced.

[0042] The present invention has been described above based on examples. These examples are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing processes, and that such modifications also fall within the scope of the present invention. [Explanation of Symbols]

[0043] 100 Transmitter, 110 Input unit, 112 Modulation unit, 114 Memory unit, 116 Control unit, 118 Amplitude variation unit, 120 Transmitter, 150 Antenna, 200 Receiver, 210 Receiver, 212 Measurement unit, 214 Memory unit, 216 Judgment unit, 218 Control unit, 220 Processing unit, 222 Demodulation unit, 224 Output unit, 250 Antenna, 1000 Communication system.

Claims

1. A demodulator that demodulates wireless signals, A measuring unit for measuring the strength value of wireless signals, A determination unit that determines whether the intensity value measured in the measurement unit satisfies the conditions, The system includes a control unit that sets the demodulation unit to either a first mode, which stops the demodulation unit, or a second mode, which operates the demodulation unit, based on the determination result in the determination unit. The control unit sets the first mode to the demodulation unit, The amplitude variation pattern in the wireless signal is assigned to each receiving device. The condition in the determination unit is that the pattern of fluctuation in the intensity value measured by the measurement unit corresponds to the pattern of fluctuation in amplitude assigned to this receiving device. The control unit is a receiving device that changes the demodulation unit from the first mode to the second mode when the determination unit determines that the conditions are met.

2. A receiving unit that receives a wireless signal that is modulated with a constant amplitude and whose amplitude fluctuates over time, Furthermore, The receiving device according to claim 1, wherein the constant amplitude modulation in the wireless signal is frequency modulation.

3. An amplitude variation unit that changes the amplitude of a wireless signal over time, The amplitude variation unit includes a transmitting unit that transmits a wireless signal whose amplitude is varied over time, The amplitude variation pattern in the amplitude variation section is assigned to each receiving device. The amplitude variation unit is a transmitting device that uses an amplitude variation pattern assigned to a receiving device which is the destination of the wireless signal.

4. A modulation unit that generates a wireless signal by performing constant amplitude modulation, Furthermore, The transmitting device according to claim 3, wherein the modulation unit performs frequency modulation.

5. A transmitting device comprising: a modulation unit that generates a wireless signal by performing constant amplitude modulation; an amplitude variation unit that varies the amplitude of the wireless signal generated by the modulation unit over time; and a transmitting unit that transmits the wireless signal whose amplitude has been varied over time by the amplitude variation unit, The receiving device comprises: a receiving unit for receiving wireless signals; a demodulation unit for demodulating the wireless signals received by the receiving unit; a measuring unit for measuring the intensity value of the wireless signals received by the receiving unit; a determination unit for determining whether the intensity value measured by the measuring unit satisfies a condition; and a control unit that sets the demodulation unit to either a first mode for stopping the demodulation unit or a second mode for operating the demodulation unit, based on the determination result of the determination unit. In the aforementioned transmitting device, The amplitude variation pattern in the amplitude variation section is assigned to each receiving device. The amplitude variation unit uses the amplitude variation pattern assigned to the receiving device that is the destination of the wireless signal. In the aforementioned receiving device, The control unit sets the first mode to the demodulation unit, The condition in the determination unit is that the pattern of fluctuation in the intensity value measured by the measurement unit corresponds to the pattern of fluctuation in amplitude assigned to this receiving device. The control unit is a communication system that changes the demodulation unit from the first mode to the second mode when the determination unit determines that the conditions are met.

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