JP2019080219A - Communication apparatus and communication method - Google Patents

Abstract

To provide a communication apparatus and a communication method that can grasp contents of information assigned to higher layer bits even when only low layer bits can be received due to a difference between low layer and high layer reception areas in a case in which hierarchical modulation is used.SOLUTION: A communication apparatus 10 includes a first modulation unit 101 that maps first data to a first layer and generates a first modulation signal, a second modulation unit 102 that maps second data different from the first data to a second layer and generates a second modulated signal, an addition unit 104 that combines the first modulation signal and the second modulation signal to generate a hierarchical modulation signal, a transmission unit 108 that transmits the hierarchical modulation signal to another communication apparatus, and a reception unit that receives a signal transmitted from the other communication apparatus. The second data includes at least one of image information, audio information, and text information. The first data includes list information indicating the content of the second data held by the communication apparatus 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a communication apparatus, a communication method, and the like, and is mainly used for communication between vehicles, between vehicles, between roads, or between walkers.

  In order to realize travel and logistics smoothly and safely, it is extremely important to secure road traffic. In recent years, in order to prevent traffic accidents and the like, technology development and rule making for the advancement of safe driving support systems have become active.

  In the safe driving support system using communication, in order to prevent an accident, various information is transmitted and received between a car, a pedestrian and a road facility. Furthermore, in the future, with the development of automatic driving technology and IoT of vehicles, an increase in the amount of information transmitted and received by the safe driving support system is expected.

  However, with the “700 MHz band Intelligent Transportation System Standard (ARIB STD-T109)” (hereinafter referred to as “T109 standard”), which is the V2X (Vehicle to X) standard, transmission is limited because of the transmission time of the signal. The time per packet can not be extended to add information. Specifically, in 3.2.3.3 (transmission time control function) of the standard, the transmission frequency is defined once per 100 ms, the transmission burst length is specified as 0.33 ms or less, and the data size that can be transmitted is It is limited to 100 bytes. Furthermore, the free application data area that can freely store data is only 60 bytes at the maximum, and there is insufficient communication capacity to send data including image data to surrounding vehicles. On the other hand, it is possible to add transmission information without extending the time per packet by using techniques such as multi-level modulation such as 16 QAM or MIMO, but using these techniques, There is a problem that the communicable range becomes narrow or there is no compatibility with the conventional product.

  Here, for example, in Patent Document 1, priority is given to information transmitted and received between vehicles, and a high priority is assigned to a low hierarchy bit, and a low priority is assigned to a high hierarchy bit, A technique for hierarchically modulating information and transmitting it is disclosed.

JP, 2009-033340, A

However, in the technology described in Patent Document 1, no countermeasure is taken based on the difference between the reception area in the low layer and the reception area in the high layer. As a result, when only low hierarchy bits can be received, it is not possible to know the content of the information allocated to high hierarchy bits (first problem).
In addition, when only low layer bits can be received, it is not possible to obtain information necessary to receive high layer bits (second problem).

Therefore, the object of the present invention is to increase the amount of data that can be transmitted by using hierarchical transmission while ensuring compatibility with a conventional product based on the conventional V2X standard, and to receive only the first hierarchy, which is a low hierarchy. It is an object of the present invention to realize a communication apparatus or the like that can know what kind of information is present in the second hierarchy, which is a high hierarchy, even in a possible situation (first object).
The object of the present invention is to increase the amount of data that can be transmitted by using hierarchical transmission while ensuring compatibility with conventional products based on the conventional V2X standard, and to receive only the first hierarchy, which is a low hierarchy. It is an object of the present invention to realize a communication apparatus or the like that can obtain information on an environment in which the second layer, which is a high layer, can receive even in a situation where it can be (second object).

In order to solve the above problem (first problem), the communication device of the present invention is
A first modulation unit (101) that maps first data to a first layer and generates a first modulation signal;
A second modulation unit (102) that maps second data different from the first data to a second layer and generates a second modulated signal;
An adder (104) that adds the first modulation signal and the second modulation signal to generate a hierarchical modulation signal;
A transmitter (108) for transmitting the hierarchical modulation signal to another communication device;
A receiving unit (201) for receiving a signal transmitted from the other communication device;
Have
The second data includes at least one of image information, audio information, text information, and the like.
The first data includes list information indicating contents of the second data held by the communication device.

According to the communication apparatus of the present invention, by using the list information, while ensuring compatibility with the conventional product based on the conventional V2X standard, the amount of data that can be transmitted is increased by using the hierarchical transmission, and the low hierarchy Even in a situation where only the first hierarchy is received, it is possible to know what kind of information exists in the second hierarchy which is the high hierarchy (first effect).
Further, according to the communication apparatus of the present invention, by using area information, while ensuring compatibility with a conventional product based on the conventional V2X standard, the amount of data that can be transmitted is increased by using hierarchical transmission, Even in a situation where only the first hierarchy, which is the low hierarchy, can receive, it is possible to obtain information about an environment where the second hierarchy, which is the high hierarchy, can receive (second effect).

Block diagram for explaining the configuration of the transmission signal processing unit of the communication apparatus of the present invention The figure explaining the signal point arrangement | positioning of the 1st hierarchy and the 2nd hierarchy mapped by the communication apparatus of this invention. A diagram for explaining the packet format of the hierarchical modulation signal transmitted from the communication apparatus of the present invention A diagram for explaining the format of the signal part in the hierarchical modulation signal of the present invention Block diagram for explaining the configuration of the reception signal processing unit of the communication apparatus of the present invention Block diagram for explaining the configuration of the communication apparatus of the present invention Block diagram for explaining the relationship between the communication apparatus of the present invention and another communication apparatus The figure explaining the packet format of the 1st hierarchy of the hierarchy modulation signal transmitted from the communication apparatus by the side of information transmission of this invention, and a 2nd hierarchy. A diagram for explaining area information transmitted from a communication apparatus on the information transmission side according to the present invention Diagram for explaining list information and type information transmitted from the communication apparatus on the information transmission side of the present invention The figure explaining the packet format of the 1st hierarchy of the hierarchy modulation signal transmitted from the communication apparatus of the information receiving side of this invention, and a 2nd hierarchy. Explanatory drawing explaining operation | movement of the communication apparatus in the 1st Embodiment of this invention Explanatory drawing explaining operation | movement of the display part of the communication apparatus of this invention Explanatory drawing explaining operation | movement of the communication apparatus in the 2nd Embodiment of this invention Explanatory drawing explaining operation | movement of the communication apparatus in the 3rd Embodiment of this invention Explanatory drawing explaining operation | movement of the communication apparatus in the 4th Embodiment of this invention Explanatory drawing explaining operation | movement of the communication apparatus in the 5th Embodiment of this invention Explanatory drawing explaining the 1st application example of this invention Explanatory drawing explaining the 2nd application example of this invention Explanatory drawing explaining the 3rd application example of this invention Explanatory drawing explaining the 4th application example of this invention

  Hereinafter, the configuration of the communication apparatus 10 common to the embodiments will be described by being divided into (1) configuration on the transmission side (transmission signal processing unit) and (2) configuration on the reception side (reception signal processing unit). Next, the overall configuration of the communication device 10 provided with (3) the configuration on the transmission side (transmission signal processing unit) and the configuration on the reception side (reception signal processing unit), and (4) the communication device 10 on the information transmission side and information The relationship with the communication apparatus 20 on the receiving side will be described. Further, (5) contents of first data and second data transmitted / received between the communication apparatus 10 on the information transmission side and the communication apparatus 20 on the information reception side will be described.

The present invention means the invention described in the claims or in the section of means for solving the problems, and the embodiments for carrying out the following inventions (hereinafter referred to as embodiments etc.) It is not limited to.
The terms in brackets in the specification mean the terms described in the claims or the section of means for solving the problems, and are not limited to the following embodiments and the like as well.
Configurations and methods described in the dependent claims of the claims, configurations and methods such as embodiments corresponding to the configurations and methods described in the dependent claims, and configurations described only in the embodiments etc. without being described in the claims And the method is any configuration and method in the present invention.
The problem described in the problem to be solved by the invention is not a known problem, but is the fact found by the inventor uniquely, and affirming the inventive step of the invention together with the means of the present invention.

(Common configuration)
(1) Configuration of transmission side (transmission signal processing unit 100)
FIG. 1 shows the configuration of a transmission signal processing unit 100 that is the configuration of the transmission side of the communication apparatus 10. As shown in FIG. The transmission signal processing unit 100 includes a first modulation unit 101, a second modulation unit 102, a power ratio adjustment unit 103, an addition unit 104, a pilot signal addition unit 105, a fast inverse Fourier transform / guard interval addition unit (hereinafter referred to as IFFT / GI). An addition unit 106, a preamble addition unit 107, and an RF unit 108 are included.

  The first modulation unit 101 includes a convolutional coding processing unit 111, an interleaving processing unit 112, and a mapping unit 113. Further, like the first modulation unit 101, the second modulation unit 102 includes a convolutional coding processing unit 121, an interleaving processing unit 122, and a mapping unit 123, and further includes an IQ conversion unit 124.

  In the first modulation unit 101 (corresponding to the “first modulation unit” of the present invention), the first data (corresponding to the “first data” of the present invention), which is transmission target data, corresponds to the second modulation unit 102. Second data (corresponding to the “second data” of the present invention), which is transmission target data different from the first data, is input to the “second modulation unit” of the present invention. Specific examples of the first data and the second data will be described later.

  The convolutional coding processing unit 111 of the first modulation unit 101 performs convolutional coding on the first data input to the first modulation unit 101 at a preset coding rate to generate a code string.

  The interleaving processing unit 112 performs interleaving processing by rearranging the order of the code string generated by the convolutional coding processing unit 111 according to a predetermined rule.

  The mapping unit 113 performs subcarrier modulation by mapping the code sequence subjected to the interleaving process to the signal point of the first layer. In the present embodiment, although the first data is modulated by QPSK as described later, any modulation scheme such as BPSK, 16 QAM, 64 QAM can be adopted. A signal (hereinafter, referred to as a first modulation signal) generated by subcarrier modulation by the mapping unit 113 (hereinafter, referred to as a first modulation signal) is input to an IQ conversion unit 124 and an addition unit 104 of a second modulation unit 102 described later.

  Similar to the first modulation unit 101, the second modulation unit 102 processes the second data by the convolutional coding processing unit 121, the interleaving processing unit 122, and the mapping unit 123, and maps the second data to the signal point of the second layer. . In this embodiment, the modulation scheme of the mapping unit 123 is QPSK as in the first layer, but as with the mapping unit 113, any modulation scheme such as BPSK, 16 QAM, 64 QAM, etc. can be adopted. The modulation scheme of the mapping unit 113 and the modulation scheme of the mapping unit 123 may be the same or different. A signal (hereinafter, referred to as a second modulation signal) generated by subcarrier modulation by the mapping unit 123 (hereinafter, a second modulation signal) is input to the IQ conversion unit 124.

  The IQ conversion unit 124 calculates the I-axis and Q-axis values of the signal point of the first data input from the mapping unit 113 and the I-axis and Q-axis of the signal point of the second data input from the mapping unit 123. And I for each Q. As a result, the output of the addition unit 104, which will be described later, becomes a bit string similar to the gray-coded 16 QAM, and the second layer is less likely to be erroneous than when simply adding without the IQ conversion unit 124. The IQ conversion unit 124 has an arbitrary configuration.

The power ratio adjustment unit 103 performs IQ based on the inter-tier power ratio which is the ratio of the signal power of the first modulation signal modulated in the first layer and the signal power of the second modulation signal modulated in the second layer. The converter 124 adjusts the power of the signal point related to the second data arranged on the IQ plane. Specifically, the power ratio adjustment unit 103 adjusts the power of the signal point of the second data by dividing the second modulation signal including the second data by the inter-hierarchical power ratio described later. The power ratio adjustment unit 103 may further adjust the value of the inter-hierarchical power ratio λ as appropriate. Thereby, the communication area in the second layer can be adjusted as appropriate. Then, the power ratio adjustment unit 103 outputs the second modulated signal after power adjustment to the addition unit 104.
In the present embodiment, the power of the second modulation signal is adjusted by the power ratio adjustment unit 103. Alternatively, the power of the first modulation signal may be adjusted, or the first modulation signal and the second modulation may be adjusted. The power of both of the signals may be adjusted.

The addition unit 104 is a signal point of the first data of the first modulation signal output from the first modulation unit 101, and a signal point of the second data of the second modulation signal output from the power ratio adjustment unit 103. Are added to generate a modulation signal (corresponding to the “layer modulation signal” of the present invention) including two layers of the first layer and the second layer. As described above, according to the present invention, a process combining the first modulation unit 101, the second modulation unit 102, and the addition unit 104 generates a modulation signal modulated in two layers of the first hierarchy and the second hierarchy. .
Here, “to add” in the present invention means to add the first modulation signal and the second modulation signal. Addition is a concept including superposition. In addition to direct vector addition of the first modulation signal and the second modulation signal, the first modulation signal and / or the second modulation signal may be subjected to an operation and then added.

FIG. 2 illustrates the modulation signal output from the adding unit 104. A cross (バ) mark is a signal point of the first data mapped to the first layer, and a ● (black circle) mark is a signal point of the second data mapped to the second layer. The distance between the origin of the IQ axis and the signal point of the first data is the power P ^1st of the signal point of the first layer, and the distance between the signal point of the first data and the signal point of the second data is This corresponds to the power P ^{2 nd} of the signal points in the second layer. Here, when the ratio of the power of the signal points of the first layer and the second layer, that is, the inter-layer power ratio, is λ, λ [dB] = P ^1st / P ^2nd is represented. That is, to adjust the power of the signal point of the second data based on the inter-tier power ratio can be said to adjust the distance between the signal point of the first layer and the signal point of the second layer. The inter-tier power ratio λ is preferably about 10 dB. If it is 10 dB or more, it is possible to minimize the deterioration of communication in the current first layer. Further, although the communication area of the second layer can be appropriately adjusted by making the inter-hierarchical power ratio λ variable, the inter-hierarchical power ratio λ may be a fixed value.

  Referring back to FIG. 1, pilot signal adding section 105 adds a pilot signal to the hierarchical modulation signal output from adding section 104. That is, a pilot signal is assigned to a predetermined pilot subcarrier. As a result, the signal output from pilot signal adding section 105 becomes a plurality of subcarrier signals including the mixed modulation signal assigned to the data subcarrier and the pilot signal assigned to the pilot subcarrier. Then, pilot signal adding section 105 inputs the subcarrier signal to IFFT / GI adding section 106.

  IFFT / GI adding section 106 converts a plurality of subcarrier signals output from pilot signal adding section 105 into a signal on the time axis by high-speed inverse Fourier transform, and then adds guard intervals. , And output to preamble adding section 107.

  The preamble adding unit 107 adds a preamble signal to the beginning of the signal to which the input guard interval is added.

The RF unit 108 (corresponding to the “transmission unit” of the present invention) converts the hierarchical modulation signal to which the preamble signal is added from the intermediate frequency or the baseband frequency to a high frequency, and transmits the “other communication” as the transmission signal through the antenna A. Send to device ".
Here, “send to another communication device” in the present invention refers to transmission to another communication device (unicast transmission), as well as reception by another communication device as a result (broadcast transmission) Also includes.

  FIG. 3 shows the packet format of the transmission signal. The packet according to this embodiment includes a short preamble (SP), a long preamble (LP1, LP2) (hereinafter collectively referred to as a preamble portion), a signal field (SIGNAL) (hereinafter referred to as a signal portion), and data fields (D1 to Dn) (hereinafter referred to as , Data section). Among them, the short preamble and the long preamble are used to establish time and frequency synchronization at the time of demodulation and to estimate propagation path distortion. The signal part is a field including information on packet length, modulation scheme and the like.

  Although the signal field and the data field are hierarchized in the transmission signal generated by the above configuration, the hierarchized region is not limited to this. For example, the signal part may be added only to the data part of the first hierarchy.

  FIG. 4 shows an example of the configuration of the signal part defined in IEEE 802.11-2007 "17.3.4 SIGNAL field". This signal unit terminates the rate field (RATE) indicating the data transmission rate, that is, the modulation scheme, the reserved field (Reserved), the length field (LENGTH) indicating the packet length, the parity field (Parity), and convolutional coding. It consists of a tail field (Tail).

  The Reserved field included in the signal part is a field reserved for future use, and is an empty field in which specific information is not stored.

(2) Configuration of the receiving side (received signal processing unit 200)
FIG. 5 shows the configuration of the reception signal processing unit 200 which is the configuration of the reception side of the communication apparatus 10. As shown in FIG.

  The reception signal processing unit 200 of the communication apparatus 10 includes an RF unit 201, a synchronization / automatic frequency control circuit (hereinafter, Sync / AFC circuit) 202, a guard interval removal / fast Fourier transform unit (hereinafter, GI removal / FFT unit) 203, A channel equalization circuit 204, a phase tracking circuit 205, a first demodulation unit 206, a second demodulation unit 207, and a shift unit 208 are included.

  The first demodulation unit 206 includes a demapping unit 211, a soft decision / deinterleaving processing unit 212, and a Viterbi decoding unit 213. Similar to the first demodulation unit 206, the second demodulation unit 207 includes a demapping unit 221, a soft decision / deinterleaving processing unit 222, and a Viterbi decoding unit 223.

  The RF unit 201 (corresponding to the “receiving unit” of the present invention) receives a hierarchical modulation signal hierarchically modulated by another communication device as a reception signal via the antenna A, and converts the high frequency to an intermediate frequency or a baseband frequency. And output to the Sync / AFC circuit 202.

  The Sync / AFC circuit 202 performs time synchronization of the FFT unit and correction processing of the carrier frequency error on the received signal. Then, the GI removing / FFT unit 203 removes the guard interval from the received signal, performs Fourier transform, converts the signal on the time axis into a signal on the frequency axis, and divides the signal into a plurality of subcarrier signals. The branched subcarrier signal is input to the channel equalization circuit 204. The channel equalization circuit 204 estimates the phase and amplitude of each subcarrier signal distorted in the transmission path of the signal, and performs correction processing using the estimated transmission path distortion. Furthermore, the phase tracking circuit 205 performs phase correction on the received signal for each OFDM symbol. Then, the phase tracking circuit 205 inputs the phase-corrected signal to the first demodulation unit 206 and the shift unit 208.

  In the first demodulation unit 206 (corresponding to the “first demodulation unit” of the present invention), the demapping unit 211 demaps (demodulates) the first modulation signal included in the first hierarchy of the hierarchy modulation signal. Next, the soft decision / de-interleaving processing unit 212 performs soft decision and de-interleaving processing on the signal output from the demapping unit 211. The signal subjected to the soft decision and the deinterleaving process is input to the Viterbi decoding unit 213. The Viterbi decoding unit 213 performs error correction decoding of the signal. By each process in the first demodulation unit 206 described above, the first data included in the first hierarchy of the hierarchy modulation signal is acquired.

  The shift unit 208 shifts the signal point of the second layer arranged on the IQ plane of the first layer on the transmission side of the other communication apparatus to the origin by the amplitude of the first layer. Here, if there is an IQ converter 124 on the transmission side, it is necessary to shift after taking the absolute value of the IQ signal before shifting, but if there is no IQ converter 124, it is sufficient to shift.

  In the second demodulation unit 207 (corresponding to the “second demodulation unit” of the present invention), each process in the demapping unit 221, the soft decision / de interleaving processing unit 222, and the Viterbi decoding unit 223 is the same as the first demodulation unit 206. I do. Thereby, the second data included in the second hierarchy of the hierarchy modulation signal is acquired.

(3) Overall Configuration of Communication Device 10 FIG. 6 is a diagram showing the overall configuration of the communication device 10. As shown in FIG. The communication device 10 includes a control unit 301, a storage unit 302, and a display unit 303 in addition to the transmission signal processing unit 100 described in (1) and the reception signal processing unit 200 described in (2).

  The control unit 301 controls the transmission signal processing unit 100, the reception signal processing unit 200, the storage unit 302, and the display unit 303. Specifically, control is performed to realize the processes of Embodiments 1 to 5 to be described later and the process of an application example to be described later. Although a dedicated or general-purpose central processing unit (CPU) is used as the control unit 301, the form thereof is not limited.

  The storage unit 302 stores information necessary for the operation of the communication device 10, is read through the control unit 301, and is used for processing of the transmission signal processing unit 100 and the reception signal processing unit 200. Further, it is also used to store the first data and the second data transmitted by the transmission signal processing unit 100 and the first data and the second data received by the reception signal processing unit 200. Area information, list information, type information, and the like, which will be described later, are also stored in the storage unit 302.

  The display unit 303 performs display based on the first data and the second data received by the received signal processing unit 200 of the communication device 10. The display contents will be described in the following first to fifth embodiments and application examples.

(4) Relationship between Communication Device 10 and Communication Device 20 Communicating With The Communication Device 10 The communication device 10 communicates with the communication device 20 having the same configuration as that described in (3). That is, as shown in FIG. 7, each communication apparatus includes a transmission signal processing unit 100 and a reception signal processing unit 200, and transmits and receives mutually necessary information. Hereinafter, the communication device 10 that transmits image information, voice information, or text information (hereinafter referred to as image information etc.) will be the communication device on the information transmission side, and the communication device 20 that receives image information etc will be the communication on the information reception side It is described as an apparatus.
The communication device 20 viewed from the communication device 10 corresponds to "another communication device" in the present invention, and the communication device 10 viewed from the communication device 20 also corresponds to "the other communication device" in the present invention.
Further, in the present embodiment, not only the communication device 10 but also the communication device 20 supports both hierarchical transmission and reception, but it is sufficient if the communication device 10 on the information transmission side includes the transmission signal processing unit 100 corresponding to hierarchical transmission. The communication device 20 on the information receiving side only needs to include the received signal processing unit 200 corresponding to hierarchical transmission. The configuration of the reception side of the communication device 10 on the information transmission side and the configuration of the transmission side of the communication device 20 on the information reception side may be compatible with the conventional V2X standard.

(5) Contents of First Data and Second Data The first data and the second data transmitted by the communication device 10 on the information transmission side will be described. FIG. 8 shows the format of the first data and the second data transmitted by the communication device 10.

  The first data mapped to the first layer includes a header area 301, a current information area 302, a free area 303, and an FCS area 304. Assuming that the modulation scheme of the first layer is QPSK and the coding rate r is 1/2, the capacity of the first layer is 188 bytes. The capacity of the free area 303 is 60 bytes.

The header area 301 stores management information of the T109 standard.
In the current information area 302, information defined by the T109 standard, such as time information, vehicle state information, vehicle attribute information, etc., is stored, and a car or the like equipped with the communication device 10 or the communication device 10 is stored here. The position information of the person in possession is also stored.
The free area 303 is an area where the user can freely store data, and stores at least one of "list information", "type information" and "area information" in the present invention. Details of these pieces of information will be described later. These pieces of information need not always be stored in all of the first layer free area 303 transmitted from the communication apparatus 10 on the information transmitting side, and may be stored in a timely manner as needed.
The FCS area 304 is an area for storing a checksum code added for error detection and correction of data.

  The second data mapped to the second hierarchy includes a fragment information area 305, a free area 306, and an FCS area 307. Assuming that the modulation scheme of the second layer is QPSK and the coding rate r is 1/2, the capacity of the second layer is 188 bytes, which is the same as that of the first layer. When the modulation scheme of the second layer is 16 QAM, the capacity of the second layer is 376 bytes.

In the fragment area 305, information necessary for combining data divided and transmitted at the time of demodulation is stored. If the size of the data stored in the free area 306 is large, it is necessary to divide and transmit. In this case, it is also necessary to transmit information for associating the divided and transmitted data with each other, and this information is stored in the fragment area 305.
The free area 306 is an area where the user can freely store data, and stores at least one of image information, voice information, text information, and the like. The “type information” of the present invention may be stored in the free area 306 instead of the free area 303. These pieces of information need not always be stored in all of the free areas 306 of the second layer transmitted from the communication apparatus 10, and may be stored in a timely manner as needed.
The FCS area 307 is an area for storing a checksum code added for error detection and correction of data, as in the FCS area 304.

  Next, area information of the present invention will be described. FIG. 9 shows area information transmitted by the communication apparatus 10 on the information transmission side.

Among the modulated signals transmitted from the communication device 10, an error is likely to occur during transmission because the signal point interval is narrower than that of the first modulated signal. Also, a difference occurs in the communicable area of the first modulation signal and the second modulation signal depending on the value of the inter-tier power ratio λ and the type of modulation scheme of the second hierarchy. Therefore, in the present invention, the communication apparatus 10 transmits, in the first data transmitted by the first modulation signal, the "area information" indicating the area that can be communicated by the second modulation signal.
Here, “area information” in the present invention means information that can be used to calculate the communicable area using calculations, tables, etc., in addition to information directly representing the communicable area with the second modulation signal. , And information indirectly indicating the communicable area by the second modulation signal.

As an example of the area information, the second hierarchy modulation parameter, that is, the “modulation scheme” executed by the second modulation unit, and “inter-hierarchical power ratio” λ indicating the ratio of the signal power of the first modulation signal to that of the second modulation signal Can be mentioned. When the modulation scheme is fixed, only the inter-tier power ratio λ may be transmitted as the area information. Further, when the inter-hierarchical power ratio λ is constant, only the modulation scheme may be transmitted as the area information.
Here, the “modulation method” in the present invention means a modulation method such as a code corresponding to each modulation method, information which can specify the modulation method on the side of another communication apparatus, etc., in addition to information directly indicating the modulation method. Also includes information that indirectly indicates. It also includes information shown in combination with the coding rate r of the error correction code.
Further, the “inter-hierarchical power ratio” in the present invention refers to a value obtained by quantizing the inter-hierarchical power ratio with a certain width, as well as information directly indicating the inter-hierarchical power ratio, and other communication devices. It also includes information that indirectly indicates the inter-tier power ratio, such as information that can identify the inter-tier power ratio on the side.

Another example of the area information is the “distance” that can be communicated by the second modulation signal. In the case of transmitting a distance, a table shown in FIG. 9 is used to obtain a communicable distance with the second modulation signal from the modulation scheme of the second modulation unit and the inter-hierarchical power ratio λ, and transmit it. May be In this case, such a table is stored in the storage unit 302 of FIG.
Here, the “distance” in the present invention means, in addition to information directly indicating the value of the distance, a value obtained by quantizing the distance with a fixed width, information that can specify the distance on the other communication device side, etc. Also includes information indicating the distance indirectly.

  Here, an example of a method of determining the second layer modulation parameters (the modulation scheme and the inter-layer power ratio λ) in the transmission apparatus 10 on the information transmission side will be described. The modulation scheme is described as selectable between QPSK and 16 QAM.

First, the second layer modulation parameter is determined according to the amount of information transmitted from the communication apparatus 10. If the amount of information to be transmitted is large, 16 QAM is selected, and if small, QPSK is selected.
Second, the second layer modulation parameter is determined according to the relative distance between the communication device 10 and the communication device 20. The relative distance can be calculated, for example, based on the mutual positional information. Select QPSK if the relative distance is long and / or reduce λ, select 16 QAM if the relative distance is close, and / or increase λ.
Third, the second layer modulation parameter is determined according to the received signal strength indicator (RSSI) of the packet transmitted from the communication device 20. Choose QPSK if RSSI is low and / or reduce λ, and select 16 QAM if RSSI is high and / or increase λ.
Fourth, the second layer modulation parameter is determined by the signal quality of a packet transmitted from the communication device 20, for example, EVM (Error Vector Magnitude). If the signal quality is bad, select QPSK and / or reduce λ, and if the signal quality is good, select 16 QAM and / or increase λ.

  These first to fourth criteria may be used alone or in any combination. Also, other criteria may be used or in combination.

  Next, list information will be described. FIG. 10 shows an example of list information transmitted by the communication apparatus 10 on the information transmission side.

The area which can be communicated by the second modulation signal among the modulation signals transmitted from the communication device 10 is narrower than the area which can be communicated by the first modulation signal. Then, when the communication device 10 transmits information such as image information, audio information, text information, etc., which is the second data in the second modulation signal, the communication device 20 receives the second modulation signal transmitted by the communication device 10. If you do not enter the area where you can, you do not know what kind of information you can get specifically. Therefore, in the present invention, the communication apparatus 10 includes “list information” indicating contents of image information etc. which is the second data held by the communication apparatus 10 in the first data transmitted by the first modulation signal. Include and send.
Here, “list information” in the present invention indicates the contents of the second data held by the communication device, and, for example, the type of the second data such as image information, audio information, text information, etc. Indicates the type of each information, such as the type of image information such as photos, videos and coupons, the type of audio information such as music and voice, the type of text information such as coupons, advertisements, traffic information, and product information. In addition, it also includes the case of indicating the semantic content that each of these pieces of information has.

  As shown in FIG. 10, categories, type 1 and type 2 are listed as examples of elements constituting list information. Examples of categories include image information, audio information, and text information. As category 1, subdivisions of categories, for example, pictures in image information, forward images, backward images, coupons, etc., voice information, voice, music, text information, coupons, advertisements, traffic information, merchandise information, etc. Can be mentioned. Furthermore, subdivisions of type 1 as type 2, for example, a traveling image or stop image in the forward image, a specific title or singer name in music, a specific shop name in coupon, a specific product name in advertisement, etc. It can be mentioned.

  Then, the communication device 10 detects all the second data held, and transmits the corresponding ID as list information. For example, when transmitting only a category as list information, an ID consisting of 2 bits (xx) allocated to the category is transmitted. When the category and the type 1 are transmitted as list information, an ID consisting of a total of 5 bits (xxyyy) allocated to the category and the type 1 is transmitted. In the case of transmitting all of the types 2 as list information, an ID consisting of a total of 9 bits (xxyyyzzzz) allocated to the types 2 is transmitted. In the case of transmitting the ID, if the same list information as that in FIG. 10 is stored in the communication device 20, the communication device 20 can decode the content indicated by the ID. Note that partial text data may be transmitted instead of or together with the ID. For example, it is conceivable to transmit text data representing type 2 instead of transmitting type 2 ID.

  Next, type information will be described. Similarly, FIG. 10 shows an example of type information transmitted by the communication apparatus 10 on the information transmission side.

When the communication device 10 receives a request signal indicating a specific content and requesting transmission of the second data from the communication device 20, the communication device 10 transmits the second data of the requested content. Here, when there are a plurality of communication devices 20, it can not be determined whether the second data transmitted from the communication device 10 is one requested by itself. Therefore, in the present invention, the communication device 10 indicates “type information indicating the content of the second data being transmitted simultaneously by the communication device 10 by the second modulation signal in the first data transmitted by the first modulation signal. Send including ".
Here, "type information" indicates the contents of the second data being transmitted simultaneously with the first data, and, like "list information", for example, image information, voice information, text information, etc. In addition to indicating the type of the second data, the type of image information such as photos, videos and coupons, the type of audio information such as music and voice, the type of text information such as coupons, advertisements, traffic information and merchandise information When showing the kind of each information, the case where the meaning content which each of these information has further is shown is also included. The "list information" and the "type information" do not necessarily have to be the same level of content.

  FIG. 10 exemplifies categories, type 1 and type 2 as an example of elements constituting type information. The contents are the same as those described as the list information.

  Then, the communication device 10 transmits, as type information, an ID corresponding to the second data currently being transmitted at the same time by the second modulation signal. However, the type information and the list information need not necessarily have the same level of content. For example, the list information may be an ID (xxyyy) including category and type 1 and the type information may be an ID (xxyyyzzzzz) including category, type 1 and type 2.

  Next, the first data and the second data transmitted by the communication device 20 on the information receiving side will be described. FIG. 11 shows the format of the first data and the second data transmitted by the communication device 20. Although the formats of the first data and the second data transmitted by the communication apparatus 10 have been described with reference to FIG. 8, the same reference numerals are used for the common parts, and the description will be omitted.

In the free area 401 of the first data mapped in the first layer, a “request signal” for requesting the communication apparatus 10 to transmit the second data including image information etc. A reception completion signal indicating that the reception of the second data consisting of the image information and the like has been completed is stored. The request signal may include, in addition to the request for the second data, information indicating the content of the specific second data.
Here, the “request signal” in the present invention is a signal indicating a request (request), and it is determined that the received communication apparatus should interpret it as a request even if it is not a request itself. Also includes the signal that It also includes the case of specifying the content and type of the second data desired to be transmitted.
Information related to the present invention is not stored in the free area 402 of the second data mapped to the second hierarchy. Furthermore, the configuration of the transmission side of the communication apparatus 20 does not have to be compatible with hierarchical modulation as described above.

  The communication device 20 receives the area information, the list information, and the type information transmitted from the communication device 10. However, for area information, the area information transmitted from the communication apparatus 10 is a second layer modulation parameter, that is, the modulation scheme executed by the second modulation unit, and / or the signals of the first modulation signal and the second modulation signal. In the case of the inter-hierarchical power ratio λ indicating the ratio of powers, the table may be used as shown in FIG. 9 to determine the communicable distance of the second modulated signal. In this case, such a table is stored in the storage unit 302 of the communication device 20.

  Next, processing in the communication apparatus 10 on the information transmission side and the communication apparatus 20 on the information reception side will be described in the first to fifth embodiments. Such disclosure is also disclosed as the operation of the communication apparatus, that is, as the invention of a method.

(Embodiment 1)
The following embodiment shows the operation of the communication apparatus 10 on the information transmission side and the communication apparatus 20 on the information reception side, that is, communication between the communication apparatus 10 and the communication apparatus 20. In these embodiments, it is assumed that the communication device 10 and the communication device 20 are each mounted in a car, but the present invention is not limited to this, for example, one possessed by a person or one that does not move, for example It may be mounted on the roadside machine.

The first embodiment shows an example of one-to-one communication.
In FIG. 12, the communication device 10 periodically transmits position information indicating the position of a vehicle on which the communication device 10 is mounted and list information, using the first modulation signal of the first hierarchy (S501).

The communication device 20 receives the position information and the list information transmitted from the communication device 10 (S502). Then, when the user of the vehicle equipped with the communication device 20 desires the information contained in the list information, the information contained in the list information is requested using the first modulation signal of the first layer of the communication device 20. The request signal is transmitted to the communication device 10 (S503).
Further, in preparation for reception of the second modulation signal of the second layer transmitted from the communication apparatus 10, “the operation of the second demodulation unit 207 of its own” is started (S504).

The communication device 10 receives the request signal transmitted from the communication device 20 (S505). In addition, when the request signal is received, “the operation of the second modulation unit 102 of its own” is started (S506).
Here, “starting the operation” in the present invention means connecting the second modulation unit to the addition unit and the transmission unit as well as starting the power supply to the second modulation unit and the second demodulation unit. It refers to transition to a state in which the result of the operation of the second modulation unit or the second demodulation unit can be enjoyed, such as connecting the second demodulation unit to the reception unit.
Then, the communication apparatus 10 transmits the area information in addition to the position information and the list information by using the first modulation signal of the first layer. At the same time, image information, audio information, text information, etc. (hereinafter referred to as image information etc.) held based on the request signal are transmitted using the second modulation signal of the second layer (S507). If the size of the image information to be held is large, it is divided and transmitted. In the example of FIG. 12, the data is divided into 1⁄3 and sequentially transmitted. The solid line arrow in the figure represents a signal received by the other party, and the broken arrow represents a signal not received by the other party.

The communication device 20 transmits from the communication device 10 when viewed from the area where the communication device 10 can communicate with the second modulation signal, that is, from the communication device 20, using the position information and the area information transmitted from the communication device 10. The display unit 303 displays an area capable of receiving the second modulated signal (hereinafter, referred to as a receivable area) (S508).
FIG. 13 is a display example on the display unit 303. The display unit 303 displays the position of the communication device 20, which is the current position of the vehicle, on the map, and displays the position of the communication device 10. In addition, the receivable area is displayed in a circle around the position of the communication device 10. Note that the area information described above may be divided in stages, and a plurality of circles may be displayed concentrically.

  Referring back to FIG. 12, when the communication device 20 does not enter the receivable area, the image information etc. transmitted from the communication device 10 as the second modulation signal can not be received. However, when entering the receivable area, the reception of the image information and the like transmitted from the communication device 10 as the second modulation signal is started (S 509). Then, when the reception of all the image information etc. for 1/3 to 3/3 is completed, the reception completion signal is transmitted using the first modulation signal of the first layer (S510), and the second demodulation unit 207 is performed. End the operation (S511).

When the communication device 10 receives the reception completion signal transmitted from the communication device 20, the communication device 10 ends the transmission of image information and the like using the second modulation signal of the second layer (S512), and the second modulation unit 102. End the operation (S513). The operation of the second modulation unit 102 may be “ended” when a predetermined time has elapsed since the transmission of the image information and the like.
Here, “to terminate the operation” in the present invention means to stop the power supply to the second modulation unit and the second demodulation unit and to connect to the addition unit and the transmission unit of the second modulation unit. Transition to a state in which the result of the operation of the second modulation unit or the second demodulation unit can not be received, such as releasing the connection to the reception unit of the second demodulation unit or releasing the connection.

  In the present embodiment, the reception completion signal is transmitted when the communication device 20 receives all the image information and the like transmitted by the second modulation signal of the second layer by the communication device 20, but in addition to this, or Alternatively, an acknowledgment signal (Ack signal) may be transmitted each time the divided and transmitted signal is received.

  As described above, according to the present embodiment, even if only the first modulation signal of the first layer can be received by using the list information, what kind of information exists in the second modulation signal of the second layer? You can know Further, by using the area information, even in a situation where only the first modulation signal of the first layer can be received, it is possible to obtain information about the range in which the second modulation signal of the second layer can be received. Furthermore, since the hierarchical transmission operation is not started until the request is received, the power consumption can be reduced. In addition, only the information requested from among a plurality of pieces of information can be transmitted efficiently. It becomes possible to use.

Second Embodiment
The second embodiment shows a case where a plurality of communication devices request the same information when there are a plurality of communication devices on the information receiving side. The communication device 20 and the communication device 30 are communication devices on the information receiving side. The number of communication devices on the information receiving side may be three or more.

  In FIG. 14, the communication device 10 periodically transmits position information indicating the position of a vehicle on which the communication device 10 is mounted and list information, using the first modulation signal of the first hierarchy (S601).

The communication device 20 receives the position information and the list information transmitted from the communication device 10 (S602). Then, when the user of the vehicle equipped with the communication device 20 desires the information included in the list information, a request for requesting the information included in the list information using the first modulation signal of the first hierarchy of the communication device 20 A signal is transmitted to the communication device 10 (S603).
At this point in time, the communication device 30 has not yet entered the area capable of receiving the first modulation signal transmitted from the communication device 10.
Note that, as in the first embodiment, the communication device 20 prepares to receive the second modulation signal of the second layer transmitted from the communication device 10 and starts the operation of the second demodulation unit 207 of its own. May be

The communication device 10 receives the request signal transmitted from the communication device 20 (S604). Also, when the request signal is received, the operation of the second modulation unit 102 of its own is started (S605).
Then, the communication apparatus 10 transmits the area information in addition to the position information and the list information by using the first modulation signal of the first layer. At the same time, the second modulation signal of the second layer is used to transmit image information etc. held based on the request signal from the communication device 20 (S606). If the size of the image information to be held is large, it is divided and transmitted. In the example of FIG. 14, it is divided into 1⁄3 and sequentially transmitted.

  When the communication device 30 enters an area capable of receiving the first modulation signal transmitted from the communication device 10, the communication device 30 receives the position information and the list information transmitted from the communication device 10 (S607). Then, when the user of the automobile equipped with the communication device 30 desires the information contained in the list information, the user requests the information contained in the list information using the first modulation signal of the first hierarchy of the communication device 30. The request signal is transmitted to the communication device 10 (S608).

  The communication device 10 receives the request signal transmitted from the communication device 30 (S609). However, since the request signal has already been received from the communication apparatus 20 in S605 and the operation of the second modulation unit 102 of its own has been started, the operation of the second modulation unit 102 is not started again.

  When the communication apparatus 20 enters an area capable of receiving the second modulated signal transmitted from the communication apparatus 10, the communication apparatus 20 starts to receive image information and the like transmitted from the communication apparatus 10 as the second modulated signal (S610). Then, when the reception of all the image information etc. for 1/3 to 3/3 is completed, the reception completion signal is transmitted using the first modulation signal of the first layer (S611).

  When the communication apparatus 10 receives the reception completion signal transmitted from the communication apparatus 20, the communication apparatus 10 has not received the reception completion signal from the communication apparatus 30. Therefore, the communication apparatus 10 uses the second modulation signal of the second layer. Continue transmitting image information etc. (S606)

  Further, when the communication apparatus 30 enters the area where it can receive the second modulated signal transmitted from the communication apparatus 10, it starts receiving the image information and the like transmitted from the communication apparatus 10 as the second modulated signal ( S612). Then, when the reception of all the image information etc. for 1/3 to 3/3 is completed, the reception completion signal is transmitted using the first modulation signal of the first layer (S613).

  When the communication device 10 receives the reception completion signal transmitted from the communication device 30, the communication device 10 determines that the transmission has been completed in response to the request from all the communication devices on the information receiving side, and the second modulation of the second layer is performed. The transmission of the image information and the like using the signal is ended (S614), and the operation of the second modulation unit 102 is ended (S615).

  As described above, according to the present embodiment, when there are a plurality of communication devices on the information receiving side, complete information can be transmitted to all communication devices.

(Embodiment 3)
The third embodiment shows a case where a plurality of communication devices request different information when there are a plurality of communication devices on the information receiving side. As in the second embodiment, the communication device 20 and the communication device 30 are communication devices on the information receiving side. The number of communication devices on the information receiving side may be three or more.

  In FIG. 15, the communication device 10 periodically transmits position information indicating the position of a vehicle equipped with itself and list information using the first modulation signal of the first layer (S701).

  The communication device 20 receives the position information and the list information transmitted from the communication device 10 (S702). Then, when the user of the vehicle equipped with the communication device 20 desires the forward image among the information included in the list information, the forward image is requested using the first modulation signal of the first hierarchy of the communication device 20. The request signal is transmitted to the communication device 10 (S703).

The communication device 10 receives the request signal transmitted from the communication device 20 (S704). In addition, when the request signal is received, the operation of the second modulation unit 102 of its own is started (S 705).
Then, the communication apparatus 10 transmits the area information and the type information in addition to the position information and the list information by using the first modulation signal of the first layer (S706). Also, the possessed forward image is transmitted using the second modulation signal of the second layer (S 706)
Since the information being simultaneously transmitted by the second modulation signal is a forward image, the type information is "forward image".

  When the communication device 30 enters an area capable of receiving the first modulation signal transmitted from the communication device 10, the communication device 30 receives the position information and the list information transmitted from the communication device 10 (S707). Then, when the user of the vehicle equipped with the communication device 30 desires a coupon among the information included in the list information, a request signal for requesting the coupon using the first modulation signal of the first hierarchy of the communication device 30 Are transmitted to the communication device 10 (S 708).

  The communication device 10 receives the request signal transmitted from the communication device 30 (S709). However, since the request signal has already been received from the communication apparatus 20 in S704 and the operation of the second modulation unit 102 of itself has been started, the operation of the second modulation unit 102 is not started again.

When the communication apparatus 20 enters an area capable of receiving the second modulated signal transmitted from the communication apparatus 10, the communication apparatus 20 starts to receive the forward image transmitted from the communication apparatus 10 as the second modulated signal (S710). Then, when reception of all forward images of 1/3 to 3/3 is completed, a reception completion signal is transmitted using the first modulation signal of the first layer (S711).
In this case, the communication device 30 also receives the type information transmitted from the communication device 100, but the received type information is the "forward image", which is different from the "coupon" requested by the request signal. The forward image received by the second modulation signal of the hierarchy is discarded (S712).

When the communication device 10 receives the reception completion signal transmitted from the communication device 20, the communication device 10 has not received the reception completion signal from the communication device 30. Therefore, the communication device 10 uses the first modulation signal of the first layer to perform position information , And in addition to the list information, area information and type information are transmitted (S713). Also, the owned coupon is transmitted using the second modulation signal of the second layer (S713)
Since the information being simultaneously transmitted in the second modulation signal is a coupon, the type information is "coupon".

  The communication device 30 receives the type information in the first modulation signal of the first layer, and receives the coupon in the second modulation signal of the second layer (S714). In this case, since the received type information is "coupon" and matches the "coupon" requested by the request signal, the coupon received by the second modulation signal of the second layer is not discarded. Then, when the reception of the coupon is completed, the reception completion signal is transmitted using the first modulation signal of the first layer (S715).

  When the communication device 10 receives the reception completion signal transmitted from the communication device 30, the communication device 10 determines that the transmission has been completed in response to the request from all the communication devices on the information receiving side, and the second modulation of the second layer is performed. The transmission of the image information and the like using the signal is ended (S716), and the operation of the second modulation unit 102 is ended (S717).

  As described above, according to the present embodiment, when there are a plurality of communication devices on the information receiving side, complete information can be transmitted to all communication devices. However, when different information is requested as described above, a waiting time occurs until the desired information is sent. Therefore, when the request signal is received in the communication apparatus 10, a response may be returned. Include expected waiting time and no response in the response. Along with this, the request cancellation signal may be transmitted from the communication device 30. This makes it possible to suppress unnecessary second layer transmission from the communication device 10.

(Embodiment 4)
In the fourth embodiment, as in the first embodiment, in the one-to-one communication, the communication device 10 on the information transmission side sets and transmits the second layer modulation parameter, and the communication device 20 on the information reception side is the communication device 10 It shows a case where image information and the like are transmitted by the second modulation signal after confirming that the reception area of the second modulation signal of the second layer is entered.

In FIG. 16, the communication device 10 periodically transmits position information indicating the position of a vehicle on which the communication device 10 is mounted and list information, using the first modulation signal of the first hierarchy (S801).
The communication device 20 receives the position information and the list information transmitted from the communication device 10 (S802). Then, when the user of the vehicle equipped with the communication device 20 desires the information included in the list information, the user requests the information included in the list information using the first modulation signal of the first hierarchy of the communication device 20. The request signal is transmitted to the communication device 10 (S803).

The communication device 10 receives the request signal transmitted from the communication device 20 (S804). In addition, when the request signal is received, it is determined whether or not the request is accepted.
If the communication apparatus 10 determines that the request is accepted, the communication apparatus 10 determines the second layer modulation parameter, and transmits the permission notification and the area information in the first layer (S805). The method of determining the second layer modulation parameter is as described in (5) and FIG.

  The communication device 20 displays the receivable area on the display unit 303 based on the area information transmitted from the communication device 10 (S806), and transmits an area detection signal to the communication device 10 at a constant cycle (S807). The area detection signal is used on the communication device 10 side to detect whether the communication device 20 has entered the coverage area. If the area detection signal is transmitted in the second layer, it can be determined that the communication device 20 has entered the receivable area when the signal can be received by the communication device 10 side. When the area detection signal is transmitted in the first layer, it may be determined that the communication apparatus 20 has entered the receivable area, using the strength (RSSI) of the area detection signal or / and the position information of the communication apparatus 20 or the like. it can. In this case, the area detection signal can be substituted by a signal of current information that is periodically transmitted.

  When the communication apparatus 10 confirms that the communication apparatus 20 has entered the receivable area using the area detection signal, the communication apparatus 10 transmits image information etc. using the second modulation signal of the second layer (S808). . Such transmission is repeatedly transmitted until the reception completion signal is received from the communication device 20. The subsequent processing is the same as that of the first embodiment.

  As described above, according to the present embodiment, since it is possible to confirm that the communication device 20 has entered the receivable area and transmit the image information and the like by the second modulation unit, it is possible to reduce power consumption and to interfere with other communication devices It is possible to suppress transmission of a signal to be a signal.

Embodiment 5
The fifth embodiment shows a case where the communication device 10 on the information transmission side starts operation by a trigger from the communication device 20 on the information reception side.

  In FIG. 17, the communication device 20 transmits a held information request signal for requesting notification of the information held by the communication device 10 on the information transmission side (S 901).

  When the communication device 10 receives the stored information request signal transmitted from the communication device 20 (S902), the communication device 10 uses the first modulation signal of the first layer to indicate the position information indicating the position of the vehicle equipped with itself and The transmission of list information is started, and these are periodically transmitted (S903). The subsequent steps are the same as in the first embodiment.

  As described above, according to the present embodiment, since it is possible to periodically transmit the position information and the list information by the first modulation unit after confirming that the stored information request signal has been received from the communication device 20, power consumption can be reduced. It is possible to suppress the transmission of a signal that is an interference signal for other communication devices.

  The first to fifth embodiments have been described above, but the present invention is not limited to these embodiments, and the steps disclosed in these embodiments may be combined as appropriate. Also, the first modulation signal of the first layer transmitted from the communication device 10 and the communication device 20 is transmitted by broadcast, and the second modulation signal of the second layer is transmitted by broadcast or unicast, but is not limited thereto. It is not a thing.

Finally, an application (application) using the communication apparatus of the present invention will be described. The steps in parentheses are described using the steps of Embodiment 1 shown in FIG. 12 as an example.
The following application example describes how to use image information and the like transmitted from the communication apparatus 10 on the information transmission side from the viewpoint of the user of the communication apparatus 20 on the information reception side.

(Example 1 of application) Search for empty space in parking lot, confirmation of congestion situation of parking lot The fullness information of the parking lot can be obtained by various means, but how crowded or how empty the space specifically You do not know if you actually go to that parking lot. And even if you go there, you may have to go around repeatedly searching for free space, wasting time and fuel. By using the communication device of the present invention, it is possible to finely grasp the crowded condition and the place of the vacant space without going to the target parking lot.

FIG. 18 is a diagram showing a procedure for confirming the presence or absence of a parking lot space.
The position of the communication apparatus 10 on the information transmission side, and the presence / absence and type of the stored information are displayed on the display unit 303 of the communication apparatus 20 on the information reception side (S501, S502). For example, as shown in FIG. 18A, the position of the communication device 10 is displayed on the map by a pointer (black circle). Further, the presence or absence of the held information held by the communication apparatus and the type of the held information can be displayed in the color or shape of the text or the pointer. The text may be displayed at all times, or may be displayed in a pop-up or pull-down format when the pointer is selected.

  A user of a car equipped with the communication device 20 presses a pointer representing the communication terminal 10 which is displayed in a parking lot where parking is desired and forward images can be transmitted (S503). As a result, as shown in FIG. 18B, the pointer changes from black circle to white circle, and the area in which the communication device 10 can transmit the forward image, ie, the area in which the communication device 20 can receive the forward image from the communication device 10 The circle is displayed centered on the pointer (S507, S508).

  The user moves the car into the coverage area with reference to the display of the coverage area on the map. Then, when the inside of the receivable area is reached, a front image obtained by photographing the front of the communication device 10 as shown in FIG. 18C is displayed on the display unit 303 (S509, S510).

  In this way, the user can check whether there is an empty space in the parking lot without having to go to the parking lot.

In addition, although this embodiment selected the motor vehicle displayed on the parking lot, various information can be acquired according to the displayed place. For example, when a forward image of a car parked in a shopping center or a parking lot of a supermarket is selected, it is possible to know not only the parking lot but also the congestion degree of the shopping center or the like. In addition, it can be determined and determined in advance whether to stop at a shopping center or the like.
Alternatively, when the front image or the rear image of a car in a traffic jam row is selected, it is possible to know the traffic congestion situation around the car in more detail.

(Example 2 of application) Checking the brake lamp state of the own vehicle When checking the car, check the brake lamp by asking another person to step on the brake pedal and check whether you turn around the rear of the car and the brake lamp lights up It must be done and it is difficult to check it alone. However, if the communication device of the present invention is used, it is possible to easily check whether the brake lamp is lit even when driving alone.

FIG. 19 is a view showing a procedure of confirming a brake lamp.
As shown in FIG. 19 (a), when a vehicle capable of transmitting a forward image is displayed immediately after the host vehicle (S501, S502), by pushing the pointer of the vehicle (S503), as shown in FIG. 19 (b) The pointer changes from black circle to white circle, and the forward image of the vehicle is received and displayed on the display unit 303 (S509, S510).

  In the case of the present embodiment, since the vehicle located immediately behind the host vehicle is usually in the receivable area, it is not necessary to display the receivable area as in the application example 1, and the pointer of the vehicle is pushed. Is immediately displaying the forward image sent from the vehicle. Of course, the coverage area may be displayed.

  In this way, the user can check and check whether the brake lamp of the host vehicle is on with the forward image transmitted from the vehicle located immediately after the host vehicle.

(Application 3) Confirmation of traveling direction of own vehicle When entering a train in a traffic jam, it is difficult to grasp the cause of the traffic congestion in the view from the own vehicle. In addition, when a large vehicle is traveling ahead, the visibility of the traffic light may be poor, and the traffic light may not be recognized unless it is immediately before the traffic light. However, if the communication device of the present invention is used, it is possible to confirm in detail the situation in the traveling direction which can not be confirmed from the host vehicle.

FIG. 20 is a diagram showing a procedure for confirming the situation in the traveling direction which can not be seen from the host vehicle.
As shown in FIG. 20 (a), when a vehicle capable of transmitting a forward image is displayed in front of the host vehicle (S501, S502), by pushing the pointer of the vehicle (S503), as shown in FIG. 20 (b) The pointer changes from black circle to white circle, and the forward image of the vehicle is received and displayed on the display unit 303 (S509, S510). Also in the case of this embodiment, since the vehicle located in front of the own vehicle is usually in the receivable area, it is not necessary to display the receivable area as in the application example 1 and the pointer of the vehicle is pushed Thus, the front image sent from the vehicle is displayed immediately. Of course, the area that can be received may be displayed.

  In this way, the user can confirm the situation in front of the host vehicle, for example, the traffic light, from the front image transmitted from the vehicle located in front of the host vehicle.

(Example 4 of application) Acquisition of store advertisement / coupon Because the vehicle travels in a wide range, it has high value as an advertising medium for carrying advertisements. For example, when a product is sold by drive-through or the like, an advertisement or coupon is transmitted to the communication device of the user of the user who purchased the product using WiFi (registered trademark), bluetooth (registered trademark) or the like. The communication device of the car distributes an advertisement and a coupon as the communication device 10 on the information transmission side. By doing this, those who are interested in the product or the store will spread the advertisement and the coupon in a chained manner, and an excellent advertising effect will be exhibited.

  FIG. 21 is a diagram showing a procedure for obtaining and transmitting an advertisement and a coupon. First, as a premise, an advertisement or a coupon is transferred to the communication device 10 of a car who has purchased a product by drive-through or the like. Then, as shown in FIG. 21A, when a vehicle capable of transmitting an advertisement or coupon is displayed on the display unit 303 of the user of the communication apparatus 20 on the information receiving side (S501, S502), the pointer of the vehicle By pressing (S503), the pointer changes from a black circle to a white circle, and an area where the vehicle can receive an advertisement or a coupon is displayed circularly around the pointer (S507, S508).

  A user of a car equipped with the communication terminal 20 on the information receiving side moves the car into the coverage area with reference to the display of the coverage area on the map. Then, when the inside of the receivable area is reached, the communication terminal 20 receives the coupon as shown in FIG. 21B and is displayed on the display unit 303 (S 509, S 510). Such delivery of coupons can be performed, for example, when the same road is transmitted in the opposite directions. In addition, the communication terminal 20 which received the coupon can now transmit an advertisement or a coupon as the communication apparatus 10 on the information transmission side.

  As described above, the advertisement and the coupon of the product can be spread in a chained manner to a person who is interested in a certain product, so that an excellent advertising effect can be exhibited.

(Other inventions)
The present specification discloses a plurality of inventions, and the following inventions are disclosed as independent inventions.

(1) Area information relation A first modulation unit (101) which maps first data to a first layer and generates a first modulation signal;
A second modulation unit (102) that maps second data different from the first data to a second layer and generates a second modulated signal;
An adder (104) that adds the first modulation signal and the second modulation signal to generate a hierarchical modulation signal;
A transmitter (108) for transmitting the hierarchical modulation signal to another communication device;
A receiving unit (201) for receiving a signal transmitted from the other communication device;
A communication device (10) having
The first data includes position information of the communication apparatus and area information indicating an area in which communication can be performed with the second modulation signal.
Communication device.

(2) Operation relation of request signal and second modulation unit A first modulation unit (101) mapping the first data to the first layer and generating a first modulation signal;
A second modulation unit (102) that maps second data different from the first data to a second layer and generates a second modulated signal;
An adder (104) that adds the first modulation signal and the second modulation signal to generate a hierarchical modulation signal;
A transmitter (108) for transmitting the hierarchical modulation signal to another communication device;
A receiving unit (201) for receiving a signal transmitted from the other communication device;
A communication device (10) having
The operation of the second modulation unit is started when the reception unit receives a request signal for requesting transmission of the second data from the other communication apparatus that has received the list information.
Communication device.

(Summary)
The features of the communication device 10 and the communication device 20 have been described above. Although the above description is based on the multicarrier modulation scheme using OFDM, the present invention is not limited to this, and other multicarrier modulation schemes or single carrier modulation schemes may be used.

Although an in-vehicle machine is mentioned as an example of communication device 10 and communication device 20, an in-vehicle machine can take various forms. For example, the form of a component or a semifinished product such as a semiconductor, an electronic circuit, a module, or an ECU (Electronic Control Unit) may be mentioned. Furthermore, the form of finished products, such as a car navigation system, a smart phone, a personal computer, and a portable information terminal, is mentioned.
Moreover, although a roadside machine is mentioned as an example of the communication apparatus 10, the form of components or semifinished products, such as a semiconductor, an electronic circuit, a module, etc., is mentioned as the form. Furthermore, the form of a finished product such as a state mounted on a traffic signal and connected with an antenna or a state mounted on a stop vehicle used for traffic control and connected with an antenna etc. may be mentioned.
Furthermore, the communication device 10 and the communication device 20 may be possessed by a person, and the form thereof is the same as that of the in-vehicle device.

Further, although the operation in each block has been described by the drawings describing the block diagram, it is needless to say that each can be grasped as a feature of the method. That is, the present specification also discloses the present invention as a method invention.
In addition, such a method can not only be realized by the above-described ones, but can also be realized as a combination of a program recorded in a recording medium such as a memory or a hard disk and a microcomputer having a dedicated or general-purpose CPU for executing the program and a memory. . The program can also be provided from a server via a communication line without passing through a recording medium. This makes it possible to always provide the latest functions through program upgrades.

  The communication device according to the present invention is mainly used for inter-vehicle communication (inter-vehicle communication), communication between a roadside device and an automobile (road-to-vehicle communication), and communication between roadside devices (inter-path communication). However, it may be used for communication between a car and a pedestrian (inter-walk communication) or communication between walkers (inter-walk communication). Furthermore, the invention is not limited to these applications.

Reference Signs List 10 communication apparatus, 101 first modulation unit, 102 second modulation unit, 104 addition unit, 108 transmission unit, 201 reception unit

Claims (17)

A first modulation unit (101) that maps first data to a first layer and generates a first modulation signal;
A second modulation unit (102) that maps second data different from the first data to a second layer and generates a second modulated signal;
An adder (104) that adds the first modulation signal and the second modulation signal to generate a hierarchical modulation signal;
A transmitter (108) for transmitting the hierarchical modulation signal to another communication device;
A receiving unit (201) for receiving a signal transmitted from the other communication device;
A communication device (10) having
The second data includes at least one of image information, audio information, text information, and the like.
The first data includes list information indicating contents of the second data held by the communication device.
Communication device (10). The first data further includes type information indicating contents of the second data being simultaneously transmitted by the second modulation signal.
The communication device according to claim 1. When the receiving unit receives a request signal for requesting transmission of the second data from the other communication device that has received the list information, the operation of the second modulation unit is started.
The communication device according to claim 1. When the reception unit receives, from the other communication device that has received the second data, a reception completion signal indicating that the reception of the second data has been completed, or the second transmission unit receives the second data from the transmission unit. The operation of the second modulation unit is ended when a predetermined time has elapsed since the data transmission.
The communication device according to claim 3. The first data further includes position information of the communication apparatus, and area information indicating an area in which communication with the second modulation signal is possible.
The communication device according to claim 1. The area information includes at least one of a modulation scheme of the second modulation unit and an inter-tier power ratio indicating a ratio of signal powers of the first modulation signal and the second modulation signal.
The communication device according to claim 5. The area information is a distance that can be communicated by the second modulation signal.
The communication device according to claim 5. The transmission unit is
Broadcast transmitting the first modulated signal;
Broadcast transmitting or unicast transmitting the second modulated signal,
The communication device according to claim 1. A receiver (201) for receiving a hierarchical modulation signal from another communication device;
A first demodulation unit (206) for demapping first data from the first modulation signal included in the first layer of the hierarchy modulation signal;
A second demodulation unit (207) for demapping second data from the second modulation signal included in the second layer of the hierarchy modulation signal;
The request signal for requesting transmission of the second data is received when the list information indicating the content of the second data, which is included in the first data and held by the other communication device, is received. A transmitter (108) for transmitting to the communication device;
A communication device (20). The content of the second data indicated by the type information when the type information indicating the content of the second data being simultaneously transmitted by the second modulation signal, which is included in the first data, is received Discards the received second data when the content of the second data different from the content of the second data requested by the request signal is different,
The communication device according to claim 9. When the receiving unit receives position information of the other communication device and area information indicating an area in which the other communication device can communicate with the second modulation signal, which are included in the first data, A display unit (303) for displaying an area where the other communication device can communicate with the second modulation signal based on the position information and the area information;
The communication device according to claim 9, comprising: The area information includes at least one of a modulation scheme of the second modulation unit and an inter-tier power ratio indicating a ratio of signal powers of the first modulation signal and the second modulation signal,
A storage unit (302) that stores a table in which the modulation scheme of the second modulation unit and / or the inter-hierarchical power ratio and the distance with which the other communication device can communicate with the second modulation signal are associated ,
The communication device according to claim 11, comprising The display unit circularly displays the communicable area centering on the position of the other communication device.
The communication device according to claim 11. A first modulation unit (101) that maps first data to a first layer and generates a first modulation signal;
A second modulation unit (102) that maps second data different from the first data to a second layer and generates a second modulated signal;
An adder (104) that adds the first modulation signal and the second modulation signal to generate a hierarchical modulation signal;
A transmitter (108) for transmitting the hierarchical modulation signal to another communication device;
A receiving unit (201) for receiving a signal transmitted from the other communication device;
A communication method to be executed by the communication device (10) having
Transmitting, as the first data, list information indicating contents of the second data held by the communication device;
Transmitting at least one of image information, audio information and text information as the second data;
Communication method. A receiver (201) for receiving a hierarchical modulation signal from another communication device;
A first demodulation unit (206) for demapping first data from the first modulation signal included in the first layer of the hierarchy modulation signal;
A second demodulation unit (207) for demapping second data from the second modulation signal included in the second layer of the hierarchy modulation signal;
A transmitter (108) for transmitting a transmission signal to the other communication device;
A communication method executed by the communication device (20) having
The transmission signal is a request signal for requesting transmission of the second data, when list information indicating the content of the second data held by the other communication device included in the first data is received. Transmitting to the other communication device as
Communication method. A first modulation unit (101) that maps first data to a first layer and generates a first modulation signal;
A second modulation unit (102) that maps second data different from the first data to a second layer and generates a second modulated signal;
An adder (104) that adds the first modulation signal and the second modulation signal to generate a hierarchical modulation signal;
A transmitter (108) for transmitting the hierarchical modulation signal to another communication device;
A receiving unit (201) for receiving a signal transmitted from the other communication device;
A program executed by the communication device (10) having
Transmitting, as the first data, list information indicating contents of the second data held by the communication device;
Transmitting at least one of image information, audio information and text information as the second data;
Run the program. A receiver (201) for receiving a hierarchical modulation signal from another communication device;
A first demodulation unit (206) for demapping first data from the first modulation signal included in the first layer of the hierarchy modulation signal;
A second demodulation unit (207) for demapping second data from the second modulation signal included in the second layer of the hierarchy modulation signal;
A transmitter (108) for transmitting a transmission signal to the other communication device;
A program executed by the communication device (20) having
The transmission signal is a request signal for requesting transmission of the second data, when list information indicating the content of the second data held by the other communication device included in the first data is received. Transmitting to the other communication device as
Run the program.