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 a technology to improve communication quality and reliability in wireless transmission lines, the space diversity method, which combines received signals by spatially separating multiple receiving antennas, and the frequency diversity method, which installs backup lines with different frequencies and switches to the backup lines when the lines deteriorate, are widely used. Generally, the space diversity method is effective in countering interference fading, but it has the disadvantage of high initial costs and high operation and maintenance costs due to the need to install multiple receiving antennas.

[0003] Patent Document 1 discloses a receiving device capable of communication by a so-called twin-path configuration among frequency diversity methods. In this invention, it is possible to transmit the same data on a plurality of different frequency signals (f1, f2). The receiving system is equipped with a bandpass filter with a bandwidth that passes each of the signals f1 and f2, and is configured to mix the received wave and the local oscillator output in a mixer to generate an intermediate frequency, which is 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-mentioned 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 and perform communication by switching the bandpass filter according to the communication status (normal / abnormal).

[0007] However, in the invention disclosed in Patent Document 1, firstly, in the case of a twin-path configuration using a bandpass filter, two waves must be received by the same antenna, so the frequency band to be used is limited. For example, it is impossible to take measures against fading by separating the above-mentioned f2 to a frequency twice that of f1. Secondly, since one of the two waves is selected, if the reception condition of the radio wave of one frequency deteriorates due to sudden fading or the line is cut off due to sudden maintenance or inspection, the switching control may not be able to be completed in time, and communication may be interrupted or the communication condition may deteriorate.

[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 capable of highly reliable and 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 modulating unit and a transmitting unit that transmits the same data as multiple signals using radio waves carrying the same data at multiple different frequencies, 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 synthesizing the signals; and the receiving device demodulating the synthesized signal.

[0012] According to a fourth aspect of the present invention, there is provided a program for controlling, by a computer, a process of receiving, as a plurality of signals, radio waves carrying the same data at a plurality of different frequencies, a process of converting the plurality of signals to the same frequency and synthesizing the plurality of signals, and a process of demodulating the synthesized 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, an optical recording medium, etc. The present invention can also be embodied as a computer program product. Effect 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 capable of highly reliable and high-quality communication. [Brief description of the drawings]

[0015] [Figure 1] 1 is a block diagram showing an example of a configuration of a receiving device according to the present disclosure. [Diagram 2]1 is a diagram showing an overview of processing in a receiving device of the present disclosure. [Diagram 3] 1 is a block diagram showing an example of a configuration of a receiving device according to the present disclosure. [Figure 4] 11 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. [Diagram 5] 10 is a flowchart for explaining the operation of a receiving device according to the present disclosure. [Figure 6] 2 is a block diagram showing an example of a hardware configuration of a receiving device according to the present disclosure. FIG. [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] 4 is a flowchart for explaining an operation in the wireless communication system of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0017] 1 is a block diagram showing an example of a 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, which are signals of multiple different frequencies and carry the same data. The received multiple signals are combined. By combining multiple signals in this manner, it is possible to obtain a higher gain or SNR (Signal to Noise Ratio), and high-quality communication can be performed even under conditions where fading occurs. In addition, since multiple channels are always received, even if the communication state of some frequency channels deteriorates, it is possible to continue communication using signals via other frequency channels, and therefore highly reliable communication can be performed.

[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 and modulated by two modulation sections (MOD1 and MOD2). The modulated signals are sent to the transmitting sections (TX1 and TX2), respectively, and are frequency-converted to different frequencies (f1 and f2) by different local oscillators (TXLO1 and TXLO2). The converted signals pass through a branching filter (BPF) and are transmitted to the receiver from the antenna.

[0021] The receiving device (realized as a receiver) receives the transmitted radio waves, splits them into their 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 synchronous signals by the devices (TXREF and RXREF) that emit reference signals. The transmitters (TX1 and TX2) generate synchronous signals f1 and f2, respectively. The signals of the same (intermediate) frequency fIF 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 when 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 synthesizes them, so that even if the communication quality of one frequency deteriorates or communication is interrupted due to fading, etc., wireless communication is possible at the other frequency, making it possible to achieve highly reliable communication. Also, by synthesizing multiple received signals, it is possible to increase the reception level, making it possible to achieve 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. As in the embodiment, the receiving device 10 according to the present disclosure includes a receiving unit 11, a synthesis unit 12, and a demodulation unit 13. The feature of this embodiment is that the receiving device 10 further includes a conversion unit 14.

[0026] The receiving unit 11 receives radio waves carrying the same data at multiple different frequencies as multiple signals. The "multiple different frequencies" may be in a range that can be received by one antenna, or may be frequencies that are sufficiently separated and received by multiple antennas. When multiple radio waves are in a frequency range that can be received by one 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 multiple received signals. Since the multiple signals are combined, the reception level of the received signal is the sum of the respective reception levels, which has the effect of providing a sufficient gain or SNR even if the reception levels of the respective frequency bands are low.

[0028] The combining in the combining unit 12 may be performed by adjusting the received signals so that they are in phase, or may be performed by adjusting the amplitude (gain) in addition to the phase so that they are in phase and in phase. In the present disclosure, the above adjustment is performed by synchronizing a reference signal in the conversion unit 14 described later and between the conversion unit 14 and a 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 Fig. 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 of the 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 in the conversion unit 14 operate in synchronization based on a reference signal that is transmitted with a predetermined accuracy. For example, the predetermined accuracy may be a time accuracy of 1PPS 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 that uses a rubidium oscillator as a source oscillator and controls the frequency by a GPS signal may be used.

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

[0034] FIG. 4 shows an example of how to send a reference signal when the converter 14 of the (transmitting) and receiving device is synchronized with the transmitting (receiving) device. Here, the case is shown where the data (TXIF / RXIF) and the reference signal (TXREF / RXREF) are superimposed, and the modem and the transceiver are connected with one signal line. The data and the sync signal generated by the opposite device or the modem itself are superimposed and sent to the modem of each system. In the modem of each system, the data is modulated by the modulator (MOD), and the sync signal is superimposed by the multiplexer (MPX) as a reference signal based on the modem itself and sent to the multiplexer of the transceiver. Here, the reference signal and the data are separated, and the data is sent from the transmitting unit (TX) as TXIF. The received reference signal is sent to the local oscillator (TXLO and RXLO) as the reference signal (TXREF and RXREF). The local oscillator that receives the reference signal transmits timing to the transmitting unit (TX) or the receiving unit (RX) and performs frequency conversion during transmission and reception.

[0035] [Explanation of operation] FIG. 5 is a flow chart for explaining the operation of the receiving device 10 of the present disclosure. Using this figure, the process from receiving radio waves by the receiving device 10 to restoring the original data will be explained along with the signal flow. As shown in this figure, when the receiving device 10 starts operating, it receives radio waves carrying the same data at multiple different frequencies as multiple signals (step S51). Next, each of the received multiple signals is converted 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 conversion to the same frequency, the multiple signals are synthesized (step S55), and the synthesized 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 has 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 mutually connected by a system bus 65. The wireless communication module 64 has the functions of a modem and a transceiver, and has 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. The receiving devices 10 may each include hardware not shown, and may not include the input / output interface 63 as necessary. In addition, 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, etc. The input device is, for example, a device for receiving user operations, such as a touch panel, etc.

[0041] The communication function of the receiving device 10 is realized mainly by a program that controls the processing module, that is, the wireless communication module 64. The control program is made up of program modules in charge of each process 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 only necessary to have 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 is put into execution by the CPU 61. The program calls a synchronization module and is executed by the CPU 61. The module transmits a signal from a reference signal generator in the wireless communication module 64 to a plurality of local oscillation circuits having a frequency conversion function for synchronization. Alternatively, a process of synchronizing with a transmitting device (not shown) may be executed by receiving a GPS signal and acquiring a time signal.

[0044] Once synchronization is complete, the control program puts the receiving module into an execution state in the CPU 61, and controls the transceiver and modem to receive radio waves of multiple frequencies through the antenna 66. Next, the conversion module is put into an 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 signal to the same predetermined frequency.

[0045] Next, the control program puts the synthesis module into execution state in the CPU 61, and executes processing to synthesize multiple signals with the same frequency in the transceiver. The synthesized signal is demodulated by a demodulation section 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 synthesizes the received signals, thereby enabling highly reliable communication that is resistant to the effects of fading, etc. Also, since the reception level increases due to synthesis, high-quality communication is possible. Furthermore, when synthesizing, a reference signal is generated to synchronize multiple local oscillators, which are then synchronized with the transmitting device, enabling highly accurate synthesis without frequency deviation.

[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 described with reference to 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 the antenna.

[0049] In Fig. 2, the communication between the transmitting device (transmitter) and the receiving device (receiver) uses two lines, f1 and f2, but the number of lines is not limited to two. 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 may be a communication device having 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 modulating unit 21 and a transmitting unit 22. The receiving device 10 has a receiving unit 11, a synthesizing unit 12, and a demodulating unit 13. The receiving device 10 may also have a converting unit 14. Details of the configuration of these receiving devices have been described in the above embodiments, and therefore will not be described here.

[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. In order to prevent frequency deviation, it is desirable for the reference signal to be synchronized with a reference signal generated for synchronization of the local oscillator in the reception device.

[0052] [Explanation of operation] FIG. 8 is a flow chart for explaining the operation of the wireless communication system 100 of the present disclosure. As shown in this figure, the transmission data is modulated in the transmitting device 20 (step S81). Next, the same data is transmitted as multiple signals by radio waves carrying the same data at multiple different frequencies (step S82). Next, the receiving device 10 receives the radio waves carrying the same data at multiple different frequencies as multiple signals (step S83). Next, each of the received multiple signals is converted to the same frequency using a different local oscillation circuit (step S84). Before this process, a process of synchronizing the multiple local oscillation circuits based on a predetermined reference signal and further synchronizing the reference signal with the transmitting device may be performed. 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 have a common hardware configuration shown in Fig. 6. Usually, they are realized as a communication device having both a receiving device and a transmitting device. Therefore, the communication module in Fig. 6 has a function related to transmission, and also has a control program and each module 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] The receiving device preferably according to claim 1, further comprising 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 claim 3 or 4, wherein the conversion unit performs synchronization based on a reference signal having a predetermined accuracy. [Appendix 6] Preferably, the receiving device according to claim 5, wherein the conversion unit generates a reference signal based on a GPS signal. [Appendix 7] Preferably, in the receiving device according to claim 2, the conversion unit is 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 as per the control program according to the fourth aspect described above. In addition, 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 the like are incorporated herein by reference. Within the framework of the entire disclosure of the present invention (including the scope of claims), modifications and adjustments of the embodiments and examples are possible based on the basic technical ideas. Furthermore, within the framework of the entire disclosure of the present invention, 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. In other words, the present invention naturally includes various modifications and corrections that a person skilled in the art would be able to make in accordance with the entire disclosure including the scope of claims and the technical ideas. In particular, with regard to the numerical ranges described in this specification, any numerical value or subrange included in the range should be interpreted as being specifically described even if not otherwise specified. [Explanation of symbols]

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

Claims

1. A receiver that receives radio waves carrying the same data at a plurality of different frequencies as a plurality of signals; A synthesis unit that synthesizes the plurality of signals; a demodulation unit for demodulating the combined signal; A receiving device having the same.

2. 2. The receiving device according to claim 1, further comprising a conversion section having a plurality of local oscillation circuits, said conversion section converting each of said plurality of signals to the same frequency using a different local oscillation circuit.

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

4. 4. The receiving device according to claim 3, wherein the conversion section is synchronized with the transmitting device by the predetermined reference signal.

5. 5. The receiving device according to claim 3, wherein the conversion section performs synchronization based on a reference signal having a predetermined accuracy.

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

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

8. A modulation section; a transmitter for transmitting the same data as a plurality of signals by radio waves carrying the same data at a plurality of 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 to the same frequency and synthesizes them; a demodulation unit for demodulating the combined signal; and a receiving device having Wireless communication system.

9. A receiving device receives 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:

10. receiving a plurality of signals carrying the same data at a plurality of different frequencies; A process of converting the plurality of signals to the same frequency and synthesizing them; demodulating the combined signal; A program that controls the above using a computer.

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