Receiving device, wireless communication system, receiving method, and program

Abstract

To improve communication quality and reliability in a wireless transmission path.SOLUTION: A receiving device includes a receiving portion that receives radio waves carrying the same data at a plurality of different frequencies as a plurality of signals, a combining portion that combines the plurality of signals, and a demodulating portion that demodulates the combined signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a receiving device, a wireless communication system, a receiving method, and a program that enable highly reliable and high-quality communication. [Background technology]

[0002] As technologies for improving communication quality and reliability in wireless transmission paths, two methods are commonly used: space diversity, which combines received signals by spatially separating multiple receiving antennas, and frequency diversity, which installs backup lines with different frequencies and switches to the backup lines when the line deteriorates. Generally, space diversity is an effective countermeasure against interference fading, but it has the disadvantage of requiring the installation of multiple receiving antennas, resulting in high initial costs and high operation and maintenance costs.

[0003] Patent Document 1 discloses a receiving device capable of communication using a so-called twin-path configuration, which is a frequency diversity method. This invention makes it possible to transmit the same data on multiple different frequency signals (f1, f2). The receiving system is equipped with bandpass filters with bandwidths that allow the f1 and f2 signals to pass, and is configured to mix the received wave and the local oscillator output in a mixer to generate an intermediate frequency, which is then detected by a demodulator. The bandpass filter is switched by a control unit depending on whether the demodulated data is normal or not. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-164554 Summary of the Invention [Problem to be solved by the invention]

[0005] The disclosures of the above prior art documents are incorporated herein by reference. The following analysis has been carried out by the present inventors.

[0006] As described above, in the invention disclosed in Patent Document 1, the control unit can select the frequency band to be used for communication by switching the bandpass filter according to the communication status (normal / abnormal).

[0007] However, in the invention disclosed in Patent Document 1, first, when a twin-path configuration is adopted to use a bandpass filter, two waves must be received by the same antenna, which imposes limitations on the frequency band that can be used. For example, it is impossible to take measures against fading by separating the above-mentioned f2 by twice the frequency of f1. Second, because the invention is configured to select one of the two waves, if the reception condition of the radio wave of one frequency deteriorates due to sudden fading or if the line is cut off due to sudden maintenance or inspection, the switching control may not be able to be completed in time, resulting in a disruption of communication or a deterioration in the communication condition.

[0008] Therefore, in one aspect of the present invention, an object is to provide a receiving device, a wireless communication system, a receiving method, and a program that are highly reliable and capable of high-quality communication. [Means for solving the problem]

[0009] According to a first aspect of the present invention, there is provided a receiving device having a receiving unit that receives radio waves carrying the same data at a plurality of different frequencies as a plurality of signals, a combining unit that converts the plurality of signals to the same frequency and combines them, and a demodulating unit that demodulates the combined signal.

[0010] According to a second aspect of the present invention, there is provided a wireless communication system including a transmitting device having a modulation unit and a transmitting unit that transmits the same data as multiple signals using radio waves carrying the same data at multiple different frequencies, and a receiving device having a receiving unit that receives the radio waves carrying the same data at the multiple different frequencies as multiple signals, a combining unit that converts the multiple signals to the same frequency and combines them, and a demodulating unit that demodulates the combined signal.

[0011] According to a third aspect of the present invention, there is provided a receiving method comprising the steps of: a receiving device receiving radio waves carrying the same data at a plurality of different frequencies as a plurality of signals; the receiving device converting the plurality of signals to the same frequency and combining them; and the receiving device demodulating the combined signal.

[0012] According to a fourth aspect of the present invention, there is provided a program for controlling, by a computer, the processing of receiving radio waves carrying the same data at a plurality of different frequencies as a plurality of signals, the processing of converting the plurality of signals to the same frequency and combining them, and the processing of demodulating the combined signal.

[0013] The program can be recorded on a computer-readable storage medium. The storage medium can be a non-transient medium such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. The present invention can also be embodied as a computer program product. [Effects of the Invention]

[0014] According to each aspect of the present invention, it is possible to provide a receiving device, a wireless communication system, a receiving method, and a program that are highly reliable and capable of high-quality communication. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a block diagram illustrating an example of the configuration of a receiving device according to the present disclosure. [Figure 2]FIG. 10 is a diagram showing an overview of processing in a receiving device of the present disclosure. [Figure 3] FIG. 2 is a block diagram illustrating an example of a configuration of a receiving device according to the present disclosure. [Figure 4] 10 is a diagram showing an example of how a reference signal is sent when a conversion unit 14 of a receiving device according to the present disclosure is synchronized with a transmitting device. FIG. [Figure 5] 10 is a flowchart illustrating the operation of a receiving device according to the present disclosure. [Figure 6] FIG. 2 is a block diagram showing an example of a hardware configuration of a receiving device according to the present disclosure. [Figure 7] 1 is a block diagram illustrating an example of a configuration of a wireless communication system according to the present disclosure. [Figure 8] 10 is a flowchart illustrating an operation of the wireless communication system of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] First, an overview of one embodiment will be described. Note that the reference numerals in the drawings attached to this overview are attached to each element as an example for convenience to facilitate understanding, and the description of this overview is not intended to be limiting in any way. In this disclosure, the drawings relate to one or more embodiments.

[0017] 1 is a block diagram showing an example of the configuration of a receiving device 10 according to the present disclosure. The receiving device 10 according to the present disclosure includes a receiving unit 11, a combining unit 12, and a demodulating unit 13.

[0018] The receiver 11 receives radio waves carrying the same data at different frequencies as a plurality of signals. The combiner 12 combines the plurality of signals. The demodulator 13 demodulates the combined signal.

[0019] In this manner, the receiving device 10 of the present disclosure receives radio waves from a transmitter, each carrying the same data, which are signals of multiple different frequencies. The received signals are then combined. By combining the multiple signals in this manner, it is possible to obtain a higher gain or SNR (Signal to Noise Ratio), enabling high-quality communication even in situations where fading occurs. Furthermore, because multiple channels are always being received, even if the communication status of some frequency channels deteriorates, communication can be continued using signals via other frequency channels, enabling highly reliable communication.

[0020] [First embodiment] [Processing Overview] 2 is a diagram showing an overview of the processing in the receiving device of the present disclosure. As shown in this diagram, data input to the transmitter is divided into two modulation sections (MOD1 and MOD2) and modulated. The modulated signals are sent to the transmitting sections (TX1 and TX2), where they are frequency-converted to different frequencies (f1 and f2) by separate local oscillators (TXLO1 and TXLO2). The converted signals pass through a branching filter (BPF) and are transmitted to the receiver via an antenna.

[0021] The receiving device (realized as a receiver) receives the transmitted radio waves, splits them into respective frequencies (f1 and f2) through a branching filter (BPF), and sends them to the receiving sections (RX1 and RX2). In the receiving sections, both signals are converted to intermediate frequency fIF signals by local oscillators (RXLO1 and RXLO2). The converted signals are combined in the combining section (COMB), demodulated by the demodulating section (DEM), and output as data.

[0022] The local oscillators on the transmitter side (TXLO1 and TXLO2) and the local oscillators on the receiver side (RXLO1 and RXLO2) generate synchronization signals using reference signal generating devices (TXREF and RXREF), respectively. The transmitters (TX1 and TX2) generate synchronized signals f1 and f2, respectively. The signals of the same (intermediate) frequency fIF, which are synchronously generated by the receivers (RX1 and RX2), are combined in the combiner (COMB), detected in the demodulator (DEM), and restored to the original data signal.

[0023] The local oscillators (TXLO1 and TXLO2, and RXLO1 and RXLO2) are synchronized by reference signals (TXREF and RXREF) in the transmitter and receiver, respectively, but if f1≠f2, the reference signals (TXREF and RXREF) are also synchronized between the transmitter and receiver.

[0024] In this way, the receiver of this embodiment receives signals of the same data at multiple frequencies, converts them to intermediate frequencies, and combines them. This allows wireless communication at the other frequency even if communication quality deteriorates or communication is interrupted due to fading or the like, thereby enabling highly reliable communication. Furthermore, by combining multiple received signals, it is possible to increase the reception level, thereby achieving high-quality communication.

[0025] [Device configuration] An example of the configuration of a receiving device according to the present disclosure is shown in Fig. 3. Similar to the embodiment, the receiving device 10 according to the present disclosure includes a receiving unit 11, a combining unit 12, and a demodulating unit 13. A feature of this embodiment is that the receiving device 10 further includes a converting unit 14.

[0026] The receiver 11 receives radio waves carrying the same data at multiple different frequencies as multiple signals. The "multiple different frequencies" may be within a range that can be received by a single antenna, or may be frequencies that are sufficiently separated so that they can be received by multiple antennas. When multiple radio waves are in a frequency range that can be received by a single antenna, being able to receive them with a single antenna can be a significant cost advantage compared to a space diversity configuration in which multiple antennas are installed physically separated. Even if the frequency bands of multiple radio waves are separated and multiple antennas are used, there is no need to physically separate the antennas, so there is an advantage in reducing the cost of antenna installation, although not as much as in the case of a single antenna.

[0027] The combiner 12 combines the received signals. Since the received signal level is the sum of the individual received levels, it has the advantage that a sufficient gain or SNR can be obtained even if the received level of each frequency band is low.

[0028] The combining unit 12 may combine the received signals by adjusting them so that they are in phase, or may combine them so that they are of equal amplitude and in phase by adjusting the amplitude (gain) in addition to the phase. In the present disclosure, the above adjustment is performed by synchronizing a reference signal within the conversion unit 14 described below and between the conversion unit 14 and the transmitting device (transmitter).

[0029] The demodulation unit 13 demodulates the combined signal, and the original data is restored by demodulation.

[0030] The converter 14 has multiple local oscillator circuits and converts each of the multiple signals to the same frequency using a different local oscillator circuit. As shown in Figure 2, when the receiver 10 receives signals of two different frequencies, it has two local oscillators, RXLO1 and RXLO2, which each oscillate to convert the signals of each frequency and generate a signal of the same intermediate frequency.

[0031] The conversion unit 14 may have a local oscillation circuit of a synthesizer type. By configuring the local oscillation circuit as a synthesizer type, it becomes possible to freely select the frequency to be transmitted and received. In implementation, a PLL (Phase Locked Loop) synthesizer or the like is used.

[0032] The multiple local oscillators included in the conversion unit 14 operate in synchronization based on reference signals that are each transmitted with a predetermined accuracy. The predetermined accuracy may be, for example, a time accuracy of 1 PPS output on the order of ±10 nsec. It is also preferable to use a signal from a GPS (Global Positioning System) or a high-accuracy signal source such as a rubidium oscillator. Furthermore, a reference signal generator using a rubidium oscillator as a master oscillator and frequency-controlled by a GPS signal may also be used.

[0033] The converter 14 may synchronize with the transmitter using a predetermined reference signal. In a frequency diversity configuration, the frequencies f1 and f2 in FIG. 2 are different. Therefore, to prevent frequency misalignment, it is necessary to synchronize the reference signal (TXREF) of the transmitter with the reference signal (RXREF) of the receiver.

[0034] Figure 4 shows an example of how a reference signal is sent when the converter 14 of the (transmitting) and receiving device synchronizes with the transmitting (receiving) device. This example shows a case in which data (TXIF / RXIF) and a reference signal (TXREF / RXREF) are superimposed, and a single signal line is used to connect the modem and transceiver. The data and a synchronization signal generated by the other device or the transceiver itself are superimposed and sent to the modem of each system. In each modem, the data is modulated by the modulator (MOD), and the synchronization signal is superimposed by the multiplexer (MPX) as a reference signal based on the modem itself and sent to the transceiver multiplexer. Here, the reference signal and data are separated, and the data is transmitted from the transmitter (TX) as TXIF. The received reference signal is sent to the local oscillators (TXLO and RXLO) as reference signals (TXREF and RXREF). The local oscillators, upon receiving the reference signal, transmit timing information to the transmitter (TX) or receiver (RX) and perform frequency conversion during transmission and reception.

[0035] [Explanation of operation] FIG. 5 is a flowchart illustrating the operation of the receiving device 10 of the present disclosure. Using this diagram, the process from receiving radio waves at the receiving device 10 to restoring the original data will be described along the signal flow. As shown in this diagram, when the receiving device 10 starts operation, it receives radio waves carrying the same data at multiple different frequencies as multiple signals (step S51). Next, it converts each of the received multiple signals to the same frequency using a different local oscillator circuit (step S54). Before this process (dotted line), the conversion unit 14 may synchronize the multiple local oscillator circuits based on a predetermined reference signal (step S52), and further synchronize the reference signal with the transmitting device (step S53). After converting to the same frequency, the multiple signals are combined (step S55), and the combined signal is demodulated (step S56).

[0036] [Hardware configuration] Next, a description will be given of the hardware configuration of the receiving device according to the first embodiment. Fig. 6 is a block diagram showing an example of the hardware configuration of the receiving device 10 according to the first embodiment.

[0037] The receiving device 10 constituting the receiving device can be configured by an information processing device (computer) and has the configuration exemplified in Fig. 6. For example, the receiving device 10 includes a CPU (Central Processing Unit) 61, a memory 62, an input / output interface 63, and a wireless communication module 64 as a communication means, which are interconnected by a system bus 65. The wireless communication module 64 has the functions of a modem and a transceiver, and includes an antenna 66, an internal or external reference signal generator (not shown), and the like.

[0038] However, the configuration shown in Fig. 6 is not intended to limit the hardware configuration of each device constituting the receiving device 10. Each receiving device 10 may include hardware not shown, and may not include the input / output interface 63 as necessary. Furthermore, the number of CPUs and the like included in the receiving device 10 is not intended to be limited to the example shown in Fig. 6, and for example, each device may include multiple CPUs.

[0039] The memory 62 is a RAM (Random Access Memory), a ROM (Read Only Memory), or an auxiliary storage device (such as a hard disk).

[0040] The input / output interface 63 is a means for interfacing with a display device and an input device (not shown). The display device is, for example, a liquid crystal display. The input device is, for example, a device that accepts user operations, such as a touch panel.

[0041] The communication function of the receiving device 10 is realized mainly by a program that controls the processing module, wireless communication module 64. The control program is made up of program modules that are responsible for the processes of reception, synchronization, conversion, synthesis, and demodulation.

[0042] The processing of the wireless communication module 64 is realized, for example, by the CPU 61 executing a control program stored in the memory 62. The program can be updated by downloading it via a network or by using a storage medium storing the program. The processing module may be realized by a semiconductor chip. That is, it is sufficient if there is some means for executing the functions performed by the processing module by some hardware and / or software.

[0043] [Hardware operation] When the receiving device 10 starts operating, a control program is called from the memory 62 and executed by the CPU 61. The program calls a synchronization module, which is executed by the CPU 61. The module sends a signal from a reference signal generator in the wireless communication module 64 to a plurality of local oscillation circuits with frequency conversion functions for synchronization. Alternatively, the receiving device 10 may receive a GPS signal and acquire a time signal to perform processing for synchronizing with a transmitting device (not shown).

[0044] Once synchronization is complete, the control program puts the receiving module into execution state in the CPU 61, controls the transceiver and modem, and receives radio waves of multiple frequencies via the antenna 66. Next, the conversion module is put into execution state in the CPU 61, and controls multiple local oscillators in the transceiver that are synchronized by the reference signal to convert the frequency of the received radio wave signal to the same predetermined frequency.

[0045] Next, the control program puts the synthesis module into execution state in the CPU 61, and executes the process of synthesizing multiple signals with the same frequency in the transceiver. The synthesized signal is demodulated by a demodulator in the modem controlled by the demodulation module, and is output as the original data to the input / output interface 63 via the system bus 65.

[0046] [Effect description] As described above, the receiving device 10 of the present disclosure receives the same data over multiple communication paths using multiple frequencies and combines the received signals, enabling highly reliable communication that is resistant to the effects of fading and the like. Furthermore, combining increases the reception level, enabling high-quality communication. Furthermore, by generating a reference signal to synchronize multiple local oscillators and then synchronizing them with the transmitting device, high-precision combining without frequency deviation is possible.

[0047] [Second embodiment] In the second embodiment, a wireless communication system including the receiving device 10 of the first embodiment and a transmitting device is provided.

[0048] [Processing Overview] An overview of the processing of the wireless communication system of the present disclosure will be explained using Fig. 2. The transmitting device is realized by the transmitter in Fig. 2. Original data is modulated by multiple modulation sections (MOD1 and MOD2), converted to frequencies f1 and f2 in the transmitting sections (TX1 and TX2) by signals from local oscillators (TXLO1 and TXLO2), respectively, passed through a branching filter (BPF), and sent to the receiver via an antenna.

[0049] In Figure 2, communication between the transmitting device (transmitter) and the receiving device (receiver) uses two lines, one via f1 and one via f2, but this is not limited to two lines. The number of antennas is also not limited to one, and multiple antennas may be used. The transmitting device may also have the configuration of a receiving device and be a communication device with the functions of both a receiver and a transmitter.

[0050] [Device configuration] 7 is a block diagram showing an example of the configuration of a wireless communication system according to the present disclosure. The wireless communication system 100 according to the present disclosure includes a transmitting device 20 and a receiving device 10. The transmitting device 20 has a modulation unit 21 and a transmission unit 22. The receiving device 10 has a reception unit 11, a synthesis unit 12, and a demodulation unit 13. The receiving device 10 may also have a conversion unit 14. Details of the configuration of these receiving devices have been explained in the above embodiments, so a description thereof will be omitted.

[0051] The modulation unit 21 modulates the data to be transmitted and places it on a carrier wave. The transmission unit 22 transmits the same data as multiple signals using radio waves carrying multiple different frequencies. The transmission unit 22 may have a local oscillator and convert the frequency of the signal to be transmitted. The transmission device 20 may have multiple local oscillators, which may operate in synchronization with a generator that generates a reference signal. To prevent frequency deviation, it is desirable that the reference signal be synchronized with the reference signal generated to synchronize the local oscillator in the reception device.

[0052] [Explanation of operation] FIG. 8 is a flowchart illustrating the operation of the wireless communication system 100 of the present disclosure. As shown in this figure, the transmitting device 20 modulates transmission data (step S81). Next, the same data is transmitted as multiple signals using radio waves carrying the same data at multiple different frequencies (step S82). Next, the receiving device 10 receives the multiple signals carrying the same data at multiple different frequencies (step S83). Next, each of the received multiple signals is converted to the same frequency using a different local oscillator circuit (step S84). Before this process, the multiple local oscillator circuits may be synchronized based on a predetermined reference signal, and the reference signal may be further synchronized with the transmitting device. After conversion to the same frequency, the multiple signals are combined (step S85), and the combined signal is demodulated (step S86).

[0053] [Hardware configuration] The wireless communication system 100 of the present disclosure includes a transmitting device 20 and a receiving device 10. These devices share the hardware configuration shown in Fig. 6. They are usually implemented as a communication device that combines a receiving device and a transmitting device. Therefore, the communication module in Fig. 6 has transmission-related functions and includes a control program as well as modules for modulation and transmission.

[0054] [Effect description] In the wireless communication system 100 of the present disclosure, the transmitting device 20 transmits transmission data using radio waves of multiple different frequencies, which are received by the receiving device 10, converted to the same frequency, and then combined. Therefore, it is possible to realize highly reliable and high-quality wireless communication.

[0055] Some or all of the above embodiments can also be described as follows, but are not limited to the following. [Appendix 1] This is the same as the receiving device according to the first aspect described above. [Appendix 2] Preferably, the receiving device according to claim 1 further comprises a conversion unit having a plurality of local oscillation circuits and converting each of the plurality of signals to the same frequency using a different local oscillation circuit. [Appendix 3] Preferably, the receiving device according to claim 2, wherein the conversion unit synchronizes a plurality of local oscillation circuits based on a predetermined reference signal. [Appendix 4] Preferably, the receiving device according to claim 3, wherein the conversion unit is synchronized with the transmitting device by means of the predetermined reference signal. [Appendix 5] Preferably, the receiving device according to appendix 3 or 4, wherein the conversion unit performs synchronization based on a reference signal having a predetermined accuracy. [Appendix 6] Preferably, the receiving device of claim 5, wherein the conversion unit generates a reference signal based on a GPS signal. [Appendix 7] Preferably, the receiving device according to claim 2, wherein the conversion unit is configured such that the local oscillation circuit is a synthesizer type. [Appendix 8] This is the same as the wireless communication system according to the second aspect described above. [Appendix 9] This is the same as the receiving method according to the third aspect described above. [Appendix 10] This is the same as the control program according to the fourth aspect described above. Note that Supplements 8 to 10 can be expanded into Supplements 2 to 7, just like Supplement 1.

[0056] The disclosures of the above-cited patent documents and other documents are incorporated herein by reference. Modifications and adjustments of the embodiments and examples are possible within the scope of the entire disclosure of the present invention (including the scope of the claims), and further based on the basic technical concept thereof. Furthermore, various combinations and selections of the various disclosed elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) are possible within the scope of the entire disclosure of the present invention. In other words, the present invention naturally includes various modifications and alterations that would be possible by a person skilled in the art in accordance with the entire disclosure and technical concept, including the scope of the claims. In particular, with regard to the numerical ranges set forth herein, any numerical value or subrange included within the range should be construed as being specifically set forth, even if not otherwise specified. [Explanation of symbols]

[0057] 10: Receiving device 11: Receiving unit 12: Synthesis section 13: Demodulation section 14: Conversion section 20: Transmitting device 21: Modulation section 22: Transmitter 61: CPU 62: Memory 63: Input / output interface 64: Wireless communication module 65: System bus 66: Antenna 100: Wireless communication system

Claims

1. a receiving unit that receives radio waves carrying the same data at a plurality of different frequencies as a plurality of signals; a combining unit that combines the plurality of signals; a demodulation unit that demodulates the combined signal; A receiving device having: A receiving device comprising: a plurality of local oscillation circuits; and a conversion unit that converts each of the plurality of signals to the same frequency using a different local oscillation circuit and inputs the converted signals to the synthesis unit.

2. 2. The receiving device according to claim 1, wherein the conversion section synchronizes a plurality of local oscillation circuits based on a predetermined reference signal.

3. 3. The receiving device according to claim 2, wherein the conversion unit synchronizes with the transmitting device using the predetermined reference signal.

4. 4. The receiving device according to claim 2, wherein the conversion section performs synchronization based on a reference signal having a predetermined accuracy.

5. 5. The receiving device according to claim 4, wherein the conversion unit generates the reference signal based on a GPS signal.

6. 2. The receiving device according to claim 1, wherein the local oscillation circuit of the conversion section is a synthesizer type.

7. a modulation section; a transmitter that transmits the same data as multiple signals using radio waves carrying the same data at multiple different frequencies; a transmitting device having a receiving unit that receives the radio waves carrying the same data at the plurality of different frequencies as a plurality of signals; a synthesis unit that converts the plurality of signals into the same frequency and synthesizes them; a demodulation unit that demodulates the combined signal; a receiving device having a plurality of local oscillation circuits and a conversion unit that converts each of the plurality of signals to the same frequency using a different local oscillation circuit and inputs the converted signals to the synthesis unit, Wireless communication system.

8. receiving, by a receiving device, radio waves carrying the same data at a plurality of different frequencies as a plurality of signals; The receiving device converts the plurality of signals to the same frequency and combines them; the receiving device demodulating the combined signal; A receiving method comprising: The receiving method further comprises a step in which the receiving device converts each of the plurality of signals to the same frequency using a separate local oscillator circuit and inputs the converted signals to the combining step.

9. receiving radio waves carrying the same data at a plurality of different frequencies as a plurality of signals; A process of converting the plurality of signals to the same frequency and synthesizing them; demodulating the combined signal; A program for controlling the above by a computer, A program for controlling, by the computer, a process of converting each of the plurality of signals to the same frequency using a separate local oscillator circuit and inputting the converted signals to the synthesizing process.

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