JP4414735B2 - Wireless data collection system and wireless data collection system base station - Google Patents

Description

  The present invention relates to a wireless data collection method and a wireless data collection system, and more particularly to a wireless data collection method and a wireless data collection system for efficiently collecting data of a slave station device in a district polling system.

  In an AVM system (Automatic Vehicle Monitoring System), a master station (also referred to as a base station or a data collection station) and a plurality of slave stations (also referred to as a mobile station or a data collection station) are connected via a wireless line. The station collects data such as location information on the mobile station side, empty / actual vehicle, direction of movement, dynamic information such as presence / absence of abnormalities, etc. via a wireless line, and displays or registers the collected data. System. For example, there is a polling method (see, for example, Patent Document 1) as a data collection method in a taxi business AVM system using a wireless line. In the polling method, the master station transmits an information collection request signal from the master station to the slave station in order to obtain information on each slave station, and each slave station sequentially sends information corresponding to the request signal to the master station. This is a transmission method. One of the polling methods is a district polling method. The district polling method is a method in which position information indicating a district (range) is added to a request signal from the master station, and information is transmitted only to the slave stations located in the requested district (range). In this area polling method, if the number of target slave stations increases, slave station data is often transmitted at the same time, the data collides on the wireless line and the data is corrupted, and the data that can be collected by the master station May decrease.

  There is also a wireless data transmission method (see, for example, Patent Document 2). This wireless data transmission system discloses a technique for transmitting downlink information from a master station to a specific slave station without stopping data collection by polling.

  In addition, in a wireless communication system (see, for example, Patent Document 3), a mobile station has a slot number A larger than the polling slot number B so that a polling response from a plurality of mobile stations can be received by the command station with almost no collision. A technique is disclosed in which the mobile station performs a polling response using slots having a slot number A or less.

  Further, in the vehicle information polling method (for example, see Patent Document 4) in the automatic vehicle position display system, data is collected at high speed from each vehicle in the service area without causing a problem of interference using a plurality of base stations. Therefore, a technique for determining a dedicated time slot from the base station information and the vehicle number of the vehicle and transmitting the information is disclosed.

JP 7-86998 A

JP 2003-249938 A JP-A-6-318893 JP 2002-64421 A

  The problem of the present invention is that in the conventional district polling system, when the number of target mobile stations increases, if the mobile station data is transmitted at the same time, the data collides on the radio line and the data is corrupted and collected at the master station. The data that can be generated may be reduced.

  An object of the present invention is to provide a wireless data collection method and a wireless data collection system that can narrow down mobile stations to be subject to district polling and reduce data collisions.

  The present invention provides a wireless data collection system that transmits a polling signal from a base station to a plurality of mobile stations using a wireless line, and collects information on the mobile station by polling, wherein the base station includes the plurality of mobile stations. When transmitting a polling signal to a station, a signal that can be selectively received by the mobile stations that are fewer than the plurality of mobile stations in the polling signal so that fewer mobile stations than the plurality of mobile stations can receive the polling signal Is configured to transmit.

  In the wireless data collection method of the present invention, the signal that can be selectively received by the mobile station is a signal related to either an odd number or an even number among vehicle numbers assigned to the mobile station. .

  In the wireless data collection method of the present invention, the signal that can be selectively received by the mobile station is a signal related to information obtained by subdividing the district polling range.

  Further, in the wireless data collection method of the present invention, when the plurality of mobile stations transmit data of each mobile station to the base station using a plurality of response slots, the plurality of slots are given priority. Is done.

  Furthermore, the present invention provides a wireless data collection system that transmits a polling signal from a base station to a plurality of mobile stations using a wireless line, and collects information on the mobile station by polling. Each of the mobile stations includes a polling signal receiver, a data transmission request signal receiver, a data generator, and a position detector of the mobile station, and the base station When transmitting a polling signal to the plurality of mobile stations, the data transmission request signal generation unit of the base station is configured to perform the polling so that fewer mobile stations than the plurality of mobile stations can receive the polling signal. A signal that can be selectively received by the mobile stations that are fewer than the plurality of mobile stations is added to the signal and transmitted, and the data transmission request signal receiver of the mobile station Configured to transmit to the base station data from the data generator in response to the selection signal.

  As described above, according to the present invention, it is possible to efficiently narrow down mobile stations that are subject to district polling, avoid data collision of mobile stations, and efficiently collect data from mobile stations at the base station. I can do it. Therefore, the information collection efficiency of the mobile station can be increased by the district polling method.

  An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, for example, an automobile AVM system. Reference numeral 101 denotes a base station (or parent station) radio. The base station radio 101 includes a transmission base station radio 102 and a reception base station radio 103. The mobile station (or the slave station) is composed of a plurality of mobile station radio devices 104-1, 104-2, ... 104-n. In addition, when calling a mobile station generically, it calls the mobile station radio | wireless machine 104. FIG.

  Thus, the base station 101 and the plurality of mobile stations 104 use, for example, uplink f1 and downlink f2 radio frequencies for polling signals and data transmission. Specifically, about 600 mobile stations and base stations communicate with each other in one channel and 10 slots, and the use frequency f1 at that time is, for example, 450 MHz, and f2 is, for example, 458 MHz.

  Next, a schematic configuration of the transmission base station radio 102 and mobile station radio 104 is shown in FIG. In FIG. 2, the base station radio 102 for transmission will be described first. Reference numeral 201 denotes a storage unit, 202 denotes a polling signal generation unit, 203 denotes a transmission switch, 204 denotes a radio, 205 denotes a data transmission request signal generation unit, and 206 denotes an antenna. The configuration of the mobile station 104 is as follows. 207 is an antenna, 208 is a radio, 209 is a polling signal receiving unit, 210 is a data transmission request signal receiving unit, 211 is a slot setting unit, 212 is a storage unit, 213 is a charge meter, and 214 is The data generation unit and 215 indicate a position detection unit. Note that the receiving base station radio 103 receives the polling response signal sent from the mobile station, but since this is the same as the conventional receiving base station radio, description thereof is omitted.

  Next, this operation will be described. First, the base station 101 performs an operation for obtaining various information from a taxi (mobile station), for example. For this reason, the storage unit 201 stores the mobile station number in an inactive state, and when the transmission switch 203 is turned ON, the mobile station number designation information to be transmitted in response to the first slot generated by the polling signal generation unit 202 and the above-mentioned inactivity The polling signal including the designation information of the mobile station number in the state and the data transmission request signal to the mobile station generated by the data transmission request signal generation unit 205 are transmitted from the wireless device 204 to each mobile station 104 via the antenna 206. Send.

  The radio wave transmitted from the base station 101 is received by the wireless device 208 via the antenna 207 on the mobile station side. Among these, the polling signal is received by the polling signal receiving unit 209, and the leading vehicle number and invalidity of the slot are received. The vehicle number of the empty slot is detected from the mobile station number in operation.

  On the other hand, the data transmission request signal receiving unit 210 detects a data transmission request signal from the base station 101. Signals detected by the polling signal receiving unit 209 and the data transmission request receiving unit 210 are sent to the slot setting unit 211. The slot setting unit 211 sets the timing of the data transmission slot of the local station and the transmission slot of the mobile station that is not operating. Further, the slot setting unit 211 continuously monitors the signal from the data transmission request signal receiving unit 210, and when the data transmission request signal is detected when the data transmission slot of the local station is reached, The generation unit 214 is activated to transmit data to be transmitted to the base station 101 via the wireless device 208 and the antenna 207. Note that the data generation unit 214 detects empty vehicles / actual vehicles based on signals from the charge meter 213 and generates data. The slot setting unit 211 is reset when the detection signal from the data transmission request signal receiving unit 210 is exhausted. The position detection unit 215 detects the position of the vehicle, for example, longitude and latitude, using, for example, a GPS system (Global Positioning System).

  Thus, in the normal district polling system, the base station 101 uses the polling signal generation unit 202, for example, as shown in FIG. 3, the base station radio 102 designates a polling start signal Pc (see FIG. 4 (a)) is transmitted. At this time, the n mobile station radios 104 within the district polling range S receive this polling start signal Pc via the radio 208 by the polling signal receiving unit 209 and receive the data transmission request signal sent simultaneously. The data transmission request signal receiving unit 210 receives the data. As a result, the slave station information is placed in one of the slave station response slots S 1, S 2,... Ss as shown in FIG. As a result, data transmission / reception is performed between the base station 101 and the mobile station 104 by district polling. However, at this time, if a plurality of mobile stations (slave stations) transmit simultaneously to the same slot, data collides and the base station (master station) cannot receive data correctly. This state will be described with reference to FIGS. FIGS. 4B and 4C schematically show the state of the collision, and FIG. 4B shows an example when there are three slave stations and the number of response slots is six. In this case, information on all three units can be collected. FIG. 4C shows that when there are 12 slave stations and the number of response slots is 6, data collision always occurs in some slots. Thus, the greater the number of mobile stations, the greater the frequency of data collisions. For example, as described above, in a system in which about 600 mobile stations and base stations communicate with each other with 1 channel and 10 slots, the frequency of collisions increases and becomes a source of complaints from taxi drivers. .

  The present invention is configured to minimize the frequency of the data collision, and the details will be described below. First, FIG. 5 shows the configuration of the polling start signal Pc transmitted from the base station radio 102 used in the present invention. The numbers in parentheses indicate the number of bits. In FIG. 5, the polling start signal Pc has a signal format of 96 bits (12 bytes), and the first 6 bits indicated by 501 are assigned to bits for transmitting information such as district polling and mobile station car number checking. . In the next 50 bits indicated by 502, the latitude and longitude information of the center position of the district polling range S is assigned to the transmitted bits. The next 6 bits indicated by 503 are assigned to bits in which area information of the district polling range S is transmitted. The 34 bits indicated by the last 504 are assigned to bits for transmitting the type of the target signal. In the present invention, the last 34 bits area 504 is used.

  Next, the mobile station (slave station) 104 that has received this polling start signal Pc transmits data to the base station (parent station) 101 using one of the response slots S1, S2,... Ss. FIG. 6 shows the structure of the response slot. The numbers in parentheses indicate the number of bits. In FIG. 6, the response slot Ss (represented by Ss since the configuration of the response slot is the same) is composed of a signal format of 96 bits (12 bytes), and in the first 6 bits indicated by 601, the mobile station The vehicle number information is assigned to the transmitted bits. In the next 50 bits indicated by 602, the position information of the own vehicle in the district polling range S, that is, the latitude and longitude information is assigned to the transmitted bits. Note that the position information of the host vehicle is obtained by the position detection unit 215 of the mobile station 104 because, for example, information on latitude and longitude is obtained from the GPS system. The next 6 bits indicated by 603 are assigned to bits to which the type of signal transmitted from the mobile station 104, for example, a response to a polling signal or an arbitrary call signal of the own vehicle is transmitted. The last 34 bits indicated by 604 are assigned to bits for transmitting status information such as mobile station status information, that is, empty / actual vehicle information, mobile station speed, moving direction, presence / absence of abnormality, and charge information. The present invention will be described in detail below.

  FIG. 7 is a diagram for explaining an embodiment of the present invention. First, in this embodiment, when the polling start signal Pc is transmitted to the mobile stations 104 existing in the district polling range S, the number of mobile stations to be polled is limited. That is, when transmitting the first polling start signal Pc, for example, “11” is transmitted to the information area 504 shown in FIG. 5 so as to respond to, for example, a mobile station having an odd number. The mobile station that can receive this polling start signal Pc is, for example, a mobile station having an odd-numbered vehicle number as shown in FIG. 7A (in the figure, slave stations 1, 3, 5,... Indicated by hatching). 104 is received by the polling signal receiving unit 209, but is not received by a mobile station having an even numbered vehicle number. Therefore, in this case, the number of mobile stations 104 that receive the polling start signal Pc is halved. Next, the base station 101 transmits, for example, “00” so as to respond to a mobile station having an even numbered vehicle number. The mobile station that can receive this polling start signal Pc is, for example, a mobile station having an even numbered car number as shown in FIG. 7B (in the figure, slave stations 2, 4, 6,... Indicated by hatching). 104 is received by the polling signal receiving unit 209. With this configuration, data collision is extremely reduced during data transmission from the mobile station 104 to the base station 101. If the polling start signal Pc is first distributed to a mobile station having an odd-numbered car number, and then the polling start signal Pc is distributed to a mobile station having an even-numbered car number, for example, in dispatching, etc. However, in such a case, when the next polling start signal Pc is distributed, the mobile station having an even-numbered car number is ahead of the mobile station having an odd-numbered car number. It is possible to maintain fairness by distributing the polling start signal Pc.

  In FIG. 8, a mobile station having an even-numbered car number receives a polling start signal Pc, and a mobile station (slave station) having an even-numbered car number transmits data using a response slot. The state is schematically shown. As shown in FIG. 8, the base station (master station) can receive data of the slave stations 2, 4, 8, 12, and 4 slave stations.

  FIG. 9 is a diagram showing another embodiment of the present invention. In the embodiment shown in FIG. 9, the district polling range S is further divided and subdivided to reduce the number of mobile stations 104 existing in the district polling range. FIG. 9 shows a case where the district polling range S is subdivided into small district polling ranges A, B, C and D. In this way, it is needless to say that the number of mobile stations existing in the small-area polling ranges A, B, C, and D can be further reduced, and data collision can be further reduced when the mobile station transmits data. In order to send such small-area polling ranges A, B, C and D from the base station 101 by the polling start signal Pc, each small area is entered in the information area 502 of the polling start signal Pc shown in FIG. Realized by inserting and transmitting the latitude and longitude information of the center position of the district polling ranges A, B, C, and D and the area information of each small district polling range A, B, C, and D in the information area 503 it can.

  FIG. 10 is a diagram showing still another embodiment of the present invention. FIG. 10 shows slots used by the mobile station 104. In this embodiment, for example, 10 slots are shown, and four slots 901-1, 901-2,... 901-4 are the slots with the highest priority, the next 902-1, 902-2, The three slots 902-3 are the next highest priority slot, the next two slots 903-1 and 903-2 are the third highest priority slot, and the last slot 904 is Indicates the slot with the lowest priority. As an example of this usage, for example, in the case of taxi dispatch, a mobile station (empty car taxi) located closest to a customer who wants a taxi uses the slot 901 with the highest priority. Slots 902 are allowed for taxis that are allowed and located the next farthest away. The last slot 904 is used to say that it is allowed to be used for the farthest taxi. By setting priorities and restricting the use of slots, data collisions are extremely reduced, and mobile stations (empty taxis) that are located closest to customers who want to take a taxi are surely connected to the base station. Data can be transmitted. Therefore, the taxi company can improve the efficiency of dispatch and improve the service.

  Although the present invention has been described in detail above, the present invention is not limited to the embodiments of the wireless data collection method and the wireless data collection system described herein, but other wireless data collection methods and wireless data than those described above. Needless to say, it can be widely applied to collection systems.

It is a figure for demonstrating one Example of this invention. It is a block diagram which shows the structure of the base station and mobile station which are used for this invention. It is a figure for demonstrating the conventional district polling system. It is a figure for demonstrating the conventional polling system. It is a figure for demonstrating the signal format of the polling start signal used in this invention. It is a figure for demonstrating the signal format of the response slot from the mobile station used in this invention. It is a figure for demonstrating the district polling system which applied this invention. It is a figure for demonstrating the polling system of this invention. It is a figure for demonstrating another Example of this invention. It is a figure for demonstrating another Example of this invention.

Explanation of symbols

  101: base station, 102: radio for transmission, 103: radio for reception, 104: mobile station, 201: storage unit, 202: polling signal generation unit, 203: transmission switch, 204, 208: radio, 206, 207: Antenna, 209: Polling signal receiving unit, 210: Data transmission request signal receiving unit, 211: Slot setting unit, 212: Storage unit, 213: Charge meter, 214: Data generation unit, 215: Position detection unit, f1: Uplink radio frequency, f2: Downlink radio frequency, Pc: Polling start signal, S1 to Ss: Each mobile station response slot.

Claims (2)

In a wireless data collection system that transmits a polling start signal from a base station to a plurality of mobile stations using a wireless line and collects information on the mobile station by polling,
The base station
A polling signal generator for generating the polling start signal;
A wireless unit that transmits the generated polling start signal;
The polling signal generator is
Means for adding latitude / longitude information for designating a polling area to the polling start signal, and a predetermined mobile station among the plurality of mobile stations existing in the polling area responds to polling Means for adding to the polling start signal information received by either a mobile station having an odd number or a mobile station having an even number .
Each of the above mobile stations
A position detection unit for obtaining position information of the own vehicle;
A data generation unit for generating data to be transmitted to the base station;
A wireless unit that receives the polling start signal transmitted from the base station;
When the received polling start signal is received, the latitude / longitude information added in the received polling start signal and the information received by either the mobile station having an odd number or the even number A polling signal receiving unit for determining whether to respond to the polling start signal based on
Furthermore, the base station
The information received by either the mobile station having an odd number or the even number is added to the polling start signal at the next polling after the polling start signal is transmitted. When the information received by either the mobile station with the odd numbered car number or the mobile station with the even numbered car number added to the start signal is the information received by the mobile station with the odd numbered car number Adds information received by mobiles with even numbered car numbers, and is either a mobile station with odd numbered car numbers or a mobile station with even numbered car numbers added to the polling start signal already sent If the information received by the mobile station having an even-numbered car number is added to the information received by the mobile station having an odd-numbered car number, the wireless data collection system is characterized by adding information received by the mobile station having an odd-numbered car number . A polling start signal is transmitted from a base station to a plurality of mobile stations using a wireless line,
In the base station of the wireless data collection system that collects information on the mobile station by polling,
The base station
A polling signal generator for generating the polling start signal;
A wireless unit that transmits the generated polling start signal;
The polling signal generator is
Means for adding latitude / longitude information for designating the area to be polled to the polling start signal, and a mobile station having an odd numbered vehicle number among the plurality of mobile stations present in the area for polling Or means for adding to the polling start signal information for either of the mobile stations having even-numbered vehicle numbers to respond to polling,
Furthermore, the base station
The information received by either the mobile station having an odd number or the even number is added to the polling start signal at the next polling after the polling start signal is transmitted. When the information received by either the mobile station with the odd numbered car number or the mobile station with the even numbered car number added to the start signal is the information received by the mobile station with the odd numbered car number Adds information received by mobiles with even numbered car numbers, and is either a mobile station with odd numbered car numbers or a mobile station with even numbered car numbers added to the polling start signal already sent The base station of the wireless data system, wherein the information received by the mobile station having an odd number is added to the information received by the mobile station having an odd number .

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