JP3056573B2 - Mobile communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication device,
The present invention relates to a mobile communication device for performing communication for confirming current and future positions between mutually moving vehicles such as automobiles.

[0002]

2. Description of the Related Art Radar has long been used as a means for confirming the position of a moving object. But,
Since the radar can only recognize a moving object existing at a position where it can be seen directly, it is suitable for recognizing an aircraft in an unobstructed sky, but is not suitable for confirming the position of a vehicle on the ground. In order to confirm the position of the vehicle on the ground, a method using light has been proposed. For example, JP-A-63-286914 discloses that
A technique for preventing collision of an unmanned vehicle by radiation of an optical vibration spectrum is disclosed.

[0003]

In a moving body such as an automobile, it is important to reliably recognize the position and moving direction of another moving body at an intersection with poor visibility.
However, conventionally proposed methods cannot always perform reliable recognition in such an environment. In the method using light, if it is shielded by a building near the intersection, sufficient communication cannot be performed, and even if radio waves are used, radio, television, wireless telephone, etc. High-precision communication may be hindered.

Accordingly, an object of the present invention is to provide a mobile communication device capable of performing high-precision communication without being affected by a shield such as a building and eliminating the influence of noise.

[0005]

Means for Solving the Problems (1) A first invention of the present application is directed to a transmitting apparatus for performing communication between mutually moving mobile objects, comprising: a direction detecting means for detecting a moving direction of the transmitting apparatus; And a transmitting means for transmitting the modulated signal to another moving object, and a modulating means for performing spread modulation on the basis of a pseudo noise code prepared corresponding to the detected moving direction. It was done.

(2) A second invention of the present application is a receiving device for performing communication between mutually moving mobile bodies,
Receiving means for receiving a signal transmitted from another mobile object, demodulating means for performing despread demodulation on the received signal and detecting a pseudo-noise code used for modulation, and a detected pseudo-noise code And a determining means for determining a moving direction of another moving body based on the above.

(3) The third invention of the present application is the receiving device according to the second invention, wherein the receiving means is constituted by a plurality of receiving systems each having a different directivity, and receiving in the plurality of receiving systems. A function of detecting the direction in which another moving body serving as a transmission source exists based on the signal strength is added to the determination means. (4) The fourth invention of the present application is the reception device according to the third invention described above.
Direction detection that detects the direction of movement of the device
Means are further provided, and the existence direction and the movement direction of another moving body
And use your own direction of travel to
Judgment of function to predict future positional relationship with other moving objects
It is added to the means.

[0008]

According to the present invention, each mobile unit detects its own moving direction, modulates a predetermined signal using a pseudo noise code corresponding to the moving direction, and transmits the modulated signal to another mobile unit. When the modulation using such a pseudo noise code is performed, the frequency band of the modulated signal is spread, so that the modulation signal is less affected by a noise signal of a specific frequency band such as a radio or a television. On the other hand, each mobile receives a signal transmitted from another mobile, performs despread demodulation on the received signal, and detects a pseudo-noise code used for modulation. By deciding which pseudo-noise code means which moving direction between moving bodies performing communication, the moving direction of the other party can be recognized by the detected pseudo-noise code. In addition, reception is performed by a plurality of receiving systems having different directivities, and if the received signal strengths in the plurality of receiving systems are detected, the presence direction of the partner can be detected.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a block diagram showing a basic configuration of a mobile communication device according to one embodiment of the present invention. This device includes a transmission device including a direction detection unit 1, a modulation unit 2, and a transmission unit 3, a reception device including a reception unit 4, a switching unit 5, and a demodulation unit 6, a determination unit 7, and a display unit 8. And a processing device composed of The mobile communication device having such a configuration is mounted on each of a plurality of mobiles, for example, vehicles.

The operation of the transmitting device is as follows. First, the direction detecting unit 1 detects the traveling direction of the own vehicle.
A known general method such as a method using terrestrial magnetism or a method using a gyro may be used to detect the traveling direction of the vehicle. The detected direction is provided to the modulator 2, where a modulated signal is generated. The feature of this device is that the information indicating the detected direction does not itself become the transmission data,
The point is that modulation is performed using arbitrary data as transmission data by using a pseudo-noise code prepared corresponding to information indicating the detected direction.

First, a brief description will be given of a modulation method using a general pseudo-noise code. When the modulation using the pseudo-noise code is performed, the frequency band is spread, and the modulated signal exhibits a much broader spectrum characteristic than the original data signal. From such a point, this modulation method is called spread modulation. Now, for example, consider a case where spread modulation is performed on transmission data as shown in FIG. That is, a spread modulation signal for binary data “10” is generated. In order to perform this modulation method, it is necessary to define in advance a pseudo noise sequence having a higher frequency than the transmission data. For example, consider a case in which a pseudo noise sequence such as "Noise Sequence A" is defined in FIG. In this case, FIG.
The spread modulation signal for the transmission data “10” shown in
The signal is as shown in FIG. That is, the noise sequence A is output as it is during the period when the transmission data is logic "1", and the inverted sequence A- ¹ which is the logical inversion of the noise sequence A is output during the period when the transmission data is logic "0". Is a spread modulation signal. The spread modulation signal generated by the modulation unit 2 is further placed on a carrier wave and
Sent from The transmission unit 3 is configured by a single omnidirectional antenna, and transmits a spread modulation signal in all directions around the vehicle.

A feature of this apparatus is that information indicating the traveling direction of the vehicle detected by the direction detecting unit 1 is not transmitted as transmission data but is used for selecting a pseudo noise sequence. In other words, in this device, the transmission data shown in FIG. 2A is always constant data (for example, “010101”).
0101 ... ”), and the transmission data itself does not have to have any meaning as information. Instead, a plurality of pseudo-noise sequences corresponding to each traveling direction are prepared, and the one corresponding to the current traveling direction of the own vehicle is selected from among them.
This is used for spreading modulation. This will be described with a specific example. For example, to represent the traveling direction of the vehicle in the next eight directions, each direction, north ... noise sequence A reversed sequence A ^-1 NE ... noise sequence B inverted sequence B ^-1 E ... noise sequence C-inverting sequences C ^{- 1} Southeast ... noise sequence D inversion series ^{D -1} south ... noise series E inverted series ^{E -1} southwest ... noise series F inverted series ^{F -1} west ... noise series G inverted series ^{G -1} northwest ... noise series H inverted series H ^- Suppose that ^one noise sequence and its inverted sequence are prepared.
At this time, for example, when the current traveling direction of the own vehicle is detected to be “southwest” by the direction detection unit 1, the modulation unit 2 converts the predetermined transmission data into the noise sequence F (and its inverted sequence). F ^-1 ) to perform spread modulation.
It is preferable to select eight codes having low cross-correlation from m-sequence codes having sharp peaks in the autocorrelation characteristic, in order to avoid interference, in the plurality of prepared noise sequences. In this way, it is possible to identify a signal spread and modulated using the same noise sequence using the phase difference. The transmission power may be made variable depending on the speed of the moving object. However, it is preferable to adjust the transmission power so that the communicable distance is about 100 m in order to avoid unnecessary interference and interference.

On the other hand, the operation of the receiving device is as follows. First, the spread modulation signal transmitted from another vehicle is received by the receiving unit 4. In this embodiment, the receiving unit 4
Are constituted by four receiving antennas 41 to 44 each having directivity (for example, cardioid type directivity). FIG. 3 shows a case where the own vehicle position is O.
The receiving sensitivity of each receiving antenna on the traveling road surface is shown. The four receiving antennas 41 to 44 are arranged such that the receiving directions are different by 90 °. FIG.
5 shows the receiving sensitivities of the four receiving antennas 41 to 44 superimposed in consideration of the receiving direction. In this example, the receiving antennas 41 to 44 are directed toward the front, rear, left, and right of the vehicle, respectively.

As described above, the apparatus shown in FIG. 1 is mounted on each vehicle. So, in this device,
At the timing shown in FIG. 5, the transmission period and the reception period are alternately time-divisionally performed. Moreover, during the reception period, the reception signals of the four reception antennas 41 to 44 are
As shown in the reception timing chart of FIG. 5, the processing is further performed in a time-division manner in four periods of front, rear, left and right. That is,
In the switching unit 5, the received signals from the receiving antennas 41 to 44 are time-divisionally switched and supplied to the demodulation unit 6. The switching cycle is set to be longer than the time required for synchronously capturing the received signal. Further, in order to eliminate interference with the transmission device, it is preferable to provide a combining circuit for subtracting a signal transmitted by the own vehicle from a received signal. In addition, spatial interference can be suppressed by disposing the antenna of the transmitting unit 3 at the center position of the four antennas of the receiving unit 4.

The demodulation unit 6 performs despread demodulation on the received signal and detects a pseudo-noise code used for modulation. That is, it is detected from the received signal which noise sequence is used to modulate the signal. Specifically, attention is focused on one of the eight prepared noise sequences, and an attempt is made to acquire a synchronization with the received signal. After synchronization is completed,
The four antennas are sequentially switched, and synchronous tracking is performed until signals from all antennas are received. If synchronization acquisition is not successful within a certain period, another noise sequence may be selected (the phase may be changed as necessary) and the same process may be repeated. Although the original transmission data is restored by the despread demodulation, the restored transmission data itself has no meaning in this apparatus. What is important is information on which noise sequence is used to modulate the signal.

The judging unit 7 and the display unit 8 constituting the processing unit have a function of making various judgments based on the demodulated signal and displaying the judgment. For example, the demodulation unit 6
In, if it is determined that the currently received signal is a signal modulated using the noise sequence F, it becomes possible to recognize that the source of this signal is traveling southwest. Also, this device can recognize the location of the source of the signal. For example, if the sensitivity arrangement shown in FIG. 4 is performed, “the signal strengths received by the antenna 41 directed forward and the antenna 44 directed rightward are equal, and the antenna 42 directed backward and No signal was received with the antenna 43 that was used ", it can be determined that the transmission source is located diagonally right front. The determination unit 7 includes the direction detection unit 1
, Information about the traveling direction of the own vehicle is given. In addition, if information about the speed of the own vehicle is given from a speed measurement system (not shown), the future own vehicle position and other vehicle positions are predicted. It is also possible to determine whether the vehicle is moving away from another vehicle, approaching another vehicle, or having a possibility of collision.

As described above, the feature of this device is that the transmitting unit 3
Since information indicating the direction of travel of the vehicle is transmitted to the surroundings as radio waves, communication becomes possible without being affected by shields as in the method using light, and pseudo noise is used as a modulation method of the transmission signal. Since the spread modulation method using codes is adopted, the spectrum range is widened, and radio, television,
It is difficult to be affected by a noise component of a specific frequency such as a wireless telephone.

In the above-described embodiment, no information is given to the transmission data itself. However, for example, if meaningful information such as the vehicle speed data of the own vehicle and the brake operation state is used as the transmission data, It is possible to transmit a lot of information to other vehicles. Also, if the transmission data is divided into a data pattern indicating a normal vehicle and a data pattern indicating an emergency vehicle such as an ambulance, it is possible to determine whether the other vehicle serving as a transmission source is a normal vehicle or an emergency vehicle. Judgment is also possible.

[0019]

As described above, according to the mobile communication apparatus of the present invention, the spread modulation method using the pseudo noise code
Since the traveling direction of the vehicle is transmitted, high-precision communication can be performed without being affected by a shielding object such as a building and eliminating the influence of noise.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a mobile communication device according to the present invention.

FIG. 2 is a diagram illustrating a spread modulation method used in the device shown in FIG.

FIG. 3 shows a configuration of a receiving unit 4 in the apparatus shown in FIG.
FIG. 3 is a diagram illustrating directivity of two antennas.

FIG. 4 is a diagram showing a configuration of a receiving unit 4 in the apparatus shown in FIG.
FIG. 3 is a diagram illustrating directivity of two antennas.

FIG. 5 is a diagram showing timing of a time division process in the device shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Direction detection part 2 ... Modulation part 3 ... Transmission part (transmission antenna) 4 ... Reception parts 41-44 ... Reception antenna 5 ... Switching part 6 ... Demodulation part 7 ... Judgment part 8 ... Display part

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B ^7/ 24-7/26 102 H04Q 7/00-7/38 G08G 1/00-9/02

Claims (4)

(57) [Claims] 1. A device for performing communication between mutually moving moving bodies, comprising: a direction detecting means for detecting a moving direction of the moving object; and a predetermined signal corresponding to the detected moving direction. A mobile communication device comprising: a modulation unit that performs spread modulation based on a prepared pseudo noise code; and a transmission unit that transmits a modulated signal to another mobile unit. 2. An apparatus for performing communication between mutually moving mobile units, comprising: receiving means for receiving a signal transmitted from another mobile unit; and despread demodulation for the received signal. And a demodulating means for detecting a pseudo-noise code used for modulation, and a judging means for judging a moving direction of another moving object based on the detected pseudo-noise code. Communication device. 3. The apparatus according to claim 2, wherein the receiving means comprises a plurality of receiving systems having different directivities, and serves as a transmission source based on received signal strengths in the plurality of receiving systems. A mobile communication device characterized in that a function of detecting the direction in which another mobile object is present is added to the determination means. 4. The device according to claim 3, wherein Direction detection means for detecting the direction of movement
Ke The direction and direction of movement of other moving objects and yourself
Using the direction of movement of
A function to predict future positional relationships has been added to the judgment means.
And a mobile communication device.