JP2003189352A - Base station for mobile communication system and vehicle position detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the position of a mobile station on the basis of communications between a fixed base station and a moving mobile station. <P>SOLUTION: The base station 10 is provided with N base station transmission/reception antennas 20. The N antennas 20 respectively have wireless zones being areas where communications with the mobile station are possible. One data frame for the communications between the base station and the mobile station includes N slots which are corresponding one to one to the N wireless zones. The presence of the mobile station in the wireless zone corresponding to the slot when communications are made with the mobile station 12 is discriminated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring the position of a mobile station based on communication between a fixed base station and a moving mobile station.

[0002]

2. Description of the Related Art Various methods and devices for detecting the position of a mobile station have been proposed for a base station which is an infrastructure side of wireless communication and a mobile station which is a terminal side. Since the mobile station definitely exists in the service area of the base station with which it is communicating, it is easy to detect the position in a macro unit at least about the size of the service area of the base station. Such a position detection function has been put to practical use in a personal handy phone system (PHS) having a small service area unit. However, in order to further subdivide and grasp the position of the mobile station within the service area, it is necessary to devise the system and equipment, and the distance to the base station is calculated trigonometrically from the strength of the radio wave from the base station. Method, transmitting a reference timing signal from the base station, calculating from the delay at the time of reception, GPS like a car navigation system
Those using (satellite navigation equipment) are being studied.

FIG. 11 shows a general DSRC (Dedicated S
FIG. 3 is a diagram showing a system configuration of hort-range communication (narrow area communication system). A plurality of base stations 110 are fixedly installed near a road or the like, and a mobile station 112 is mounted on a vehicle and moves. The base station 110 includes a host device 11
4 transmits communication information, which is transmitted to the mobile station 112 on the road. The mobile station 112 receives the information from the base station 110 installed in the vicinity at that time.

The base station communication control unit 116 of the base station 110
Receives the data to be communicated with the mobile station from the higher-level device 114, converts and configures the data according to the specifications to be put on a radio wave, and the base station transceiver device 118 as transmission data.
Output to. As a specification to be put on the radio wave, a data configuration specification called a frame which is composed of a data group called a plurality of slots as described later is usually used. The base station transmission / reception device 118 modulates and frequency-converts the input transmission data, and outputs it as a high frequency signal to the base station transmission / reception antenna 120. Base station transmitting / receiving antenna 120
Outputs the input high frequency signal as a radio wave. The mobile station 112, which receives the radio wave output from the base station transmitting / receiving antenna 120, frequency-converts, demodulates, decomposes, and reconverts the transmission data in the reverse order of the base station 110, and displays the transmission data to the user. That is, the mobile station transmitting / receiving antenna 122
The received signal received at is sent to the mobile station transmitter / receiver 124, where it is demodulated and sent to the mobile station communication controller 126. The mobile station communication control device 126 sends the received information to the human interface unit (HMI unit) 128, where it notifies the driver of the vehicle of the information.

From the mobile station 112, the base station 11
Communication is performed with the higher-level device 114 via 0. Usually, the transmission frequency from the base station to the mobile station and the transmission frequency from the mobile station to the base station are different from each other.
x) method is often adopted. As shown in FIG. 12A, the base station transmitting / receiving antenna 120 normally transmits a radio wave downward, and forms a wireless zone 130 for communication as shown in FIG. 12B on the road surface. DSR
In C, TDMA (Time Division Multiple
Since the access time division multiple access) system is adopted, a communication frame composed of a plurality of communication slots as shown in FIG. 13 is transmitted as data for communication on the radio wave. The mobile station 112 receives one or a plurality of slots designated for each mobile station. 12
A plurality of mobile stations 112 are included in the wireless zone 130 shown in (b).
, The base station 110 specifies to each mobile station 112 which slot to use for each mobile station, and communicates with each mobile station by using that slot. Independent communication is possible. Usually, a dedicated slot containing communication control information including designation of a slot is provided on the frame shown in FIG. 13, and the head slot is often used for this.

[0006] In such road-to-vehicle communication using DSRC, the service area of one base station is as small as several tens of square meters, and even large ones are used for wireless communication in units of lengths of about 100 meters along the road. Since the mobile station is a vehicle and it occupies a large area and usually passes through the service area in a short time, it is necessary to understand the position of the vehicle in the service area compared to a mobile phone. It wasn't too expensive for the car above.

[0007]

In the above-mentioned method, even if there are a plurality of mobile stations in the wireless zone, it is possible to separately communicate with each mobile station. However, where the mobile station exists in the wireless zone. I do not know what to do. As mentioned above, there is not a high demand for individual location confirmation for vehicles that are traveling on normal roads, but parking locations at parking lots, refueling locations at gas stations, and queues at drive-through stores There is a demand for position detection of a specific vehicle within a relatively narrow range such as position. More specifically, when guiding a specific vehicle to an empty parking position in the parking lot, the parking lot manager may want to know which vehicle is currently communicating. In addition, at a gas station, there is a demand to know which refueling hose used to refuel from the position where the vehicle stopped. In a drive-through store, when delivering a product to a vehicle located away from a product receiving window, there is a demand to specify which vehicle the product should be delivered to.

Japanese Unexamined Patent Publication (Kokai) No. 5-151497 relates to a vehicle position detection method for grasping the approaching direction of a vehicle entering an intersection, and information depending on the traveling direction of the vehicle such as traffic congestion information and weather information. In order to provide the service, the vehicle position is known and the traveling direction is known. In this example, the base station modulates and transmits a signal of a different code sequence for each road crossing at an intersection, and the mobile station that receives this signal knows its position by knowing which code sequence was received. It is a thing. But in this way,
A special transmission / reception mechanism is required for position detection,
There is a problem that both the base station and the mobile station are costly. There is also a problem that the positions of all vehicles cannot be grasped because only mobile stations equipped with a special mechanism can know the positions.

The present invention has been made in order to solve the above-mentioned problems, and has a simple structure, in particular, a conventional mobile station, which is more detailed in the communication area of the base station.
The purpose is to detect the position of the mobile station.

[0010]

A base station of a mobile communication system according to the present invention has a plurality of partial areas which are part of the communication area of the base station, and communication of communication data frames with the partial areas. It corresponds to the slot for. If communication with a mobile station is possible in a certain communication slot, it can be determined that the mobile station exists in the partial area corresponding to this slot.

The partial area may be a transmission / reception area of a plurality of antennas provided in a base station. Then, each antenna is driven corresponding to one communication slot.

The partial area can be formed by providing a plurality of antenna elements in the base station and controlling the phase of each antenna element to control the transmitting and receiving directions. That is, the phase given to each antenna element is changed for each communication slot to obtain a partial area corresponding to the slot.

Further, a vehicle position detecting device according to another aspect of the present invention includes a base station installed on a road facility and a mobile station mounted on a vehicle, in a data frame for communication,
The present invention relates to a device that performs communication in a format including a plurality of time-divided communication slots. The base station transmits the information of the communication slot to a partial area, which is a part of the communication area of the base station, corresponding to the communication slot. Upon receiving the transmitted information, the mobile station transmits information from the mobile station side. By associating the slot with the partial area at this time, the position of the mobile station, that is, the vehicle can be specified in the partial area unit.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1. FIG. 1 is a configuration block diagram of the first embodiment. A plurality of base stations 10 are fixedly installed near a road or the like, and a mobile station 12 is mounted on a vehicle and moves. Communication information is sent from the host device 14 to the base station 10, and the communication information is sent to the mobile station 12 on the road.
The mobile station 12 is the base station 10 installed in the vicinity at that time.
Receive information from.

The base station communication control device 16 of the base station 10 is
Data to be communicated with the mobile station is input from the host device 14, the data is converted and configured according to the specifications to be placed on a radio wave, and the data is output to N base station transceiver devices 18 provided as transmission data. The base station transmission / reception device 18 modulates and frequency-converts the input transmission data, and outputs it as a high-frequency signal to N base station transmission / reception antennas 20 corresponding to the base station transmission / reception device 18 on a one-to-one basis. N is a natural number of 2 or more. N individual base station transceiver devices 1
8 and the base station transmitting / receiving antenna 20 need to be differentiated from each other, the suffixes 18,-
2, ..., -N will be added for explanation. Specifications that can be placed on the radio wave
A data structure specification called a frame is used which is composed of a group of data called a plurality of slots. Further, an identification signal for identifying the slot is given to each slot.

The mobile station 12 is configured similarly to the prior art mobile station 112 described above. That is, the mobile station transmission / reception antenna 22 receives a signal from the base station 10, the mobile station transmission / reception device 24 demodulates the signal, and the mobile station communication control device 26 demodulates the human interface unit (HMI).
Section 28 to inform the driver of the vehicle of the information.
Transmission from the mobile station 12 to the base station 10 is performed in the reverse order.

The base station 10 further has a zone control device 30 for switching and operating a plurality of base station transceiver devices 18. The base station communication control device 16 outputs the slot identification signal to the zone control device 30 as a radio zone selection signal based on a predetermined association,
The zone control device 30 transmits / receives a transmission / reception ON / OFF signal to the base station transmission / reception device 18 based on the input radio zone selection signal.
Output to. This transmission / reception ON / OFF signal is transmitted to only one of the N base station transmission / reception devices 18 at a certain time.
Is a signal controlled to turn on. Transmission is performed from the base station transmission / reception antenna 20 corresponding to the base station transmission / reception device 18 to which this ON signal is transmitted.

The radio zone selection signal is transmitted in correspondence with time-divided slots in the data frame of communication. Therefore, the slot and the base station transceiver device 18,
The base station transmitting / receiving antenna 20 and the wireless zone 32 have a one-to-one correspondence.

The N base station transmitting / receiving antennas 20 have different transmission ranges, that is, radio zones 32. As for the wireless zone 32, the subscripts -1, -2, ..., -N are associated with the base station transmitting / receiving antenna 20 as necessary.
Will be described. That is, the radio zone corresponding to the n-th base station transmitting / receiving antenna 20-n is denoted by reference numeral 32-n.

FIG. 2 is a diagram showing a radio zone 32 formed by the base station transmitting / receiving antenna 20. In the figure, (a) is an elevation view and (b) is a plan view. In this embodiment, as shown in FIG. 2, base station transmitting / receiving antennas 20-1, 20-2, ..., 2
0-n, ..., 20-N formed wireless zones 32-1, 32-2, ...
.., 32-n, ..., 32-N are arranged so that the individual base station transmitting / receiving antennas 20 are adjacent to each other without a gap. As a result, a plurality of partial areas (radio zones) are formed in the communication area of the base station. Further, the communication area of the base station is entirely covered by the plurality of partial areas.

3 and 4 are transmitting and receiving slot 34-n when mobile station 12 is designated to communicate using the nth slot 34-n of slot 34 in the frame. It is a figure showing the moment. FIG. 3 shows the relationship between radio zones and slots when there are N slots in one frame. Figure 4 (a)
Is an elevation view showing the wireless zone 32, and (b) is a plan view. In this embodiment, when transmitting / receiving slot n, the zone control device 30 controls so that only the base station transmitting / receiving device 18-n performs transmission / reception. Therefore, the base station 10 and the mobile station 12 can communicate only when the mobile station 12 is in the zone 32-n. As a result, it can be seen that the mobile station 12 exists in the zone 32-n.

Another advantage of this embodiment is that frequency utilization efficiency is improved. For example, in order to form a wireless zone as shown in FIG. 2, a method of forming a plurality of wireless zones by using a plurality of base stations itself can be considered. In this case, adjacent wireless zones simultaneously transmit wireless radio waves. As a result, the radio waves are interfered with each other, which causes a problem that normal communication cannot be performed. There is also a method of using different frequencies for each wireless zone to avoid radio wave interference, but in this case a huge frequency band is required, and it is a global trend to limit the radio wave bandwidth as much as possible. This is contrary to the tendency of radio wave administration.

Embodiment 2. FIG. 5 is a schematic configuration diagram of the second embodiment of the present invention. About the same composition as the above-mentioned embodiment, the same numerals are attached and the explanation is omitted. In this embodiment, unlike the general DSRC system configuration in FIG. 11, N base station transmitting / receiving antennas 20 are provided instead of the base station transmitting / receiving antennas, and a station transmitting / receiving device 18 and a base station transmitting / receiving antenna 20 are provided. A high frequency switching device 36 is provided between the two, and the high frequency switching device 36 switches and operates the base station transmitting / receiving antenna 20 to which the high frequency signal is transmitted from the base station transmitting / receiving device 18.
The zone control device 30 controls this switching operation.

According to this structure, the base station transmitter / receiver directly switches the high frequency signal input / output to / from the base station transmitter / receiver antenna, so that it is not necessary to have a plurality of base station transmitter / receivers 18. Therefore, the base station configuration can be simple and inexpensive. This is effective when the high frequency signal has a relatively low frequency and the signal level is not so large.

Embodiment 3. 6 is a schematic configuration diagram of Embodiment 3 of the present invention. About the same composition as the above-mentioned embodiment, the same numerals are attached and the explanation is omitted. In this embodiment, an array antenna 40 having M antenna elements 38 is provided instead of the antennas having different radio zones in the above-described embodiments.
Here, M is a natural number of 2 or more. The base station transmitter / receiver 18 and the base station antenna elements 38 correspond to each other on a one-to-one basis, and a phase shifter 42 is arranged between the corresponding ones. When the M base station transceiver devices 18, the base station antenna elements 38, and the phase shifters 42, which are M in number, are individually distinguished, the suffixes -1, -2, ...

The phase shifter 42 changes the phase of the high frequency signal transmitted to the base station transmitting / receiving antenna element 38. By properly adjusting the phase provided by each phase shifter 42, the transmission direction of the radio wave transmitted from the array antenna 40 can be controlled. Therefore, by providing each base station transmitting / receiving antenna element 38 with an appropriate phase according to the zone selection of the zone control device 30, it is possible to form a plurality of wireless zones 32 similar to those in the above-described embodiments. According to the configuration, it is possible to integrate a plurality of antennas, and the base station can be downsized.

Fourth Embodiment FIG. 7 is a schematic configuration diagram of the third embodiment of the present invention. About the same composition as the above-mentioned embodiment, the same numerals are attached and the explanation is omitted. Similar to the embodiment shown in FIG. 6, this embodiment has an array antenna 40 composed of a plurality of base station transmitting / receiving antenna elements 38. A characteristic of this embodiment is that digital beamforming is used to equivalently form a wireless zone by digital processing in a relatively low frequency region before frequency conversion into a high frequency.

The K digital modulation / demodulation circuits 44 modulate the transmission data input from the base station communication control device 16 and output the modulated signals to the digital phase shift circuit 46. The digital phase shift circuit 46 performs weighting and changes the phase based on a predetermined calculation formula from the K modulation signals that have been input, generates M digital transmission signals, and outputs M A / D-
It outputs to each D / A converter 48. The A / DD / A converter 48 D / A converts these digital transmission signals,
It is output to the M base station transceiver devices 50 as an analog transmission signal. The base station transmitter / receiver 50 frequency-converts the input analog transmission signal into a high frequency signal, and then outputs the high frequency signal to the base station transmission / reception antenna element 38. The base station transmitting / receiving antenna element 38 radiates a high frequency signal as a radio wave, and a radio zone is formed based on a predetermined calculation formula. The communication from the mobile station to the base station is performed in the reverse order. In this example, since the phase control can be performed by digital processing, there is an advantage that miniaturization can be performed and complicated processing can be performed, and a plurality of wireless zones can be equivalently formed at the same time.

Embodiment 5. FIG. 8 is a schematic configuration diagram of the third embodiment of the present invention. About the same composition as the above-mentioned embodiment, the same numerals are attached and the explanation is omitted. In this embodiment, a zone determination device 52 is added to the embodiment shown in FIG. The zone determination device 52 inputs, from the base station communication control device, information regarding which wireless zone was used for the slot assigned to the mobile station, and determines whether the mobile station is located at the overlapping portion between the wireless zones. To do. FIG. 9 shows the relationship between the slots and the wireless zones at this time. In this example, slots for communicating with a mobile station whose position is to be determined are assigned to a-th slot 34-a and b-th slot 34-b, and zone 32-a is assigned to slot 32-a in slot 34-a.
Zone 32-b is associated with 4-b. In this example, if communication is possible in both the slot 34-a and the slot 34-b, it is understood that the mobile station exists in the overlapping portion C between the zone 32-a and the zone 32-b shown in FIG.

[0031]

EFFECTS OF THE INVENTION A plurality of partial areas that are part of the communication area of one base station are set. A plurality of time-divided slots in one communication data frame are associated with this partial area. By this means, if the time when communication is performed through a certain slot is known, the position of the mobile station that is the object of communication can be specified for each partial area. Moreover, the configuration of the mobile station does not need to be changed from the conventional configuration.

The above-mentioned partial area can be formed by installing a plurality of antennas in one base station and separately setting the communicable range of each antenna, so that each antenna can be easily installed. A simple structure can be used under the conditions. Further, even in a condition where there are many obstacles, it can be dealt with by appropriately setting the installation position of the antenna.

Further, the partial region can be formed by changing the phase of the signal transmitted to the antenna element of the array antenna and controlling the transmission direction thereof. In this case, the antenna is integrated. The base station can be miniaturized.

Further, when the presence of the mobile station is determined in a plurality of partial areas, it can be determined that the mobile station exists in the overlapping portion of these partial areas, and thus, the more detailed mobile station position determination can be performed. Is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a first embodiment.

FIG. 2 is a diagram showing a configuration of a wireless zone (divided area) and a relationship between the configuration and a base station transmission / reception antenna.

FIG. 3 is a diagram showing a relationship between a wireless zone (divided area) and a communication slot.

FIG. 4 is an explanatory diagram of position detection of a mobile station.

FIG. 5 is a diagram showing a schematic configuration of a second embodiment.

FIG. 6 is a diagram showing a schematic configuration of a third embodiment.

FIG. 7 is a diagram showing a schematic configuration of a fourth embodiment.

FIG. 8 is a diagram showing a schematic configuration of a fifth embodiment.

FIG. 9 is a diagram showing a relationship between a slot and a wireless zone when the same mobile station is detected in two communication slots.

FIG. 10 is a diagram for explaining a case where a mobile station exists in an overlapping portion of two wireless zones.

FIG. 11 is a diagram showing a schematic configuration of a conventional mobile communication device.

FIG. 12 is a diagram showing a relationship between a base station transmitting / receiving antenna and a wireless zone in the apparatus of FIG.

13 is a diagram showing the relationship between communication data frames and slots in the device of FIG.

[Explanation of symbols]

10 base stations, 12 mobile stations, 16 base station communication control devices, 18 base station transceiver devices, 30 zone control devices,
32 wireless zone, 34 communication slot, 36 high frequency switching device, 38 antenna element, 40 array antenna, 42 phase shifter.

Claims (5)

[Claims] 1. A base station of a mobile communication system for performing communication between a fixedly installed base station and a mobile station, wherein the base station is time-divided within a data frame of the communication. Information of the communication slot is transmitted to a partial area corresponding to each communication slot, which is a part of the communication area of the base station, and further, the mobile station transmits the information corresponding to the transmission information. A base station of a mobile communication system, which receives information and determines, based on the reception time, that the mobile station exists in a partial area corresponding to the communication slot. 2. The base station has a plurality of antennas each having a unique communication area corresponding to the partial area, and the plurality of antennas are communication-controlled in correspondence with the communication slots. A base station of the mobile communication system according to claim 1. 3. The base station of the mobile communication system according to claim 1, wherein the base station includes an array antenna having a plurality of antenna elements, and controls the phase of each antenna element to form the partial area. . 4. The base station, when it is determined that one mobile station is located in a plurality of partial areas, determines that the mobile station exists in an area where the plurality of partial areas overlap. A base station of a mobile communication system according to any one of 1. 5. A vehicle position detecting device for performing communication between a base station installed on a road or on-road equipment related to a vehicle and a mobile station mounted on the vehicle to identify the position of the vehicle. The communication includes a plurality of communication slots time-divided in the data frame, and the base station corresponds to each of the communication slots, with respect to a partial area obtained by dividing the communication area of the base station. , Transmitting the information of the communication slot, the mobile station receiving the transmitted information, transmits the information corresponding thereto, the base station, based on the time point of the information transmitted from the mobile station, A vehicle position detection device that specifies a partial area to which a vehicle equipped with a mobile station belongs and detects the position of the vehicle.