JP2702218B2 - Wireless communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a wireless communication system in which a master station collects various information from a plurality of slave stations according to an answerback command, and aims to eliminate unnecessary answerback time. The command includes a plurality of slave stations that need to be called when the plurality of slave stations are further divided into a plurality of slave stations,
When each slave station extracts the slave station group number of the answer back command and detects that it is the slave station group number of its own station, it transmits answer back information in a time slot allocated to its own station, or When there is only one child station in the child station group number related to the call, the answer back command includes the child station group number and the child station number, and each child station receives the answer back instruction. When the slave station group number and the slave station number of the own station are detected, answer back information is transmitted in the first time slot.

[Industrial applications]

The present invention relates to a wireless communication system, and more particularly to a wireless communication system in which a master station collects various types of information from a plurality of slave stations according to an answerback command.

In a disaster management radio digital cell call system for municipalities, an answer back command is sent from a master station to a plurality of slave stations, and the slave station sends various information collected in response to the command to the master station. In this case, as the amount of information increases, it is required to reduce the time required for collecting information.

[Conventional technology]

In a conventional wireless communication system that collects various types of information by such an answerback command, if a response is made from a plurality of slave stations at the same time during information collection, collision of slave station collection information occurs in the master station. In order to prevent this, it is necessary to shift the transmission time between the slave stations for transmission.

As a method, as shown in JP-A-52-15590, a time is allocated in advance when each slave station transmits a response, and the slave station that has received the selective call responds at that time. A transmission method has been proposed.

That is, when one master station A collects information from 400 slave stations B as shown in FIG. 7, the answer back time slots T1 to T400 of each slave station are allocated as shown in FIG.

Then, as shown in the time chart of FIG. 9, when the master station A issues an answer back command to all the slave stations simultaneously by radio (time slot T0), the time point S at which the command is issued is given.
Therefore, each slave station responds in a time slot allocated to itself.

Accordingly, the slave station 1 transmits the collection information of its own station to the master station A in response to the time slot T1, the slave station 2 also responds to the time slot T2, and the slave station 400 responds to the time slot T400. .

[Problems to be solved by the invention]

In such a conventional wireless communication system, as shown in FIG. 7, although only three of the slave stations 1, 2, and 400 returned answer back, unnecessary slave stations 3 were unnecessary.
Requires ~ 399 answerback time slots,
This has a problem that as the number of slave stations increases, the useless answer back time increases.

Therefore, an object of the present invention is to eliminate unnecessary answer-back time in a wireless communication system in which a master station collects various information from a plurality of slave stations according to an answer-back command.

[Means and actions for solving the problem]

In the wireless communication system according to the present invention, as shown in FIG. 1, the slave stations 1 to 400 shown in FIG.
Divide into ~ G20. It is necessary for the master station to know to which slave station the answer back command should be given. In the example of FIG. 1, only the slave stations 1, 20, 42, 43 and 400 have an answer back command. Shall be required.

In the present invention, there are the following three modes as communication systems in such a case.

First mode: This mode is applied when there are a plurality of calling slave stations in the slave station group. As shown in the time chart of FIG. When the answer back command is transmitted in time slot T0 to all the slave stations so that only the slave station group G1 responds, only the slave stations 1 and 20 of the slave stations 1 to 20 of the slave station group number G1 are transmitted. As shown, answerback information is transmitted to the master station A in the time slots T1 and T20 assigned to the own station.

Then, when the answer back command to the slave station group G1 ends, the answer back command is not transmitted because the slave station group G2 of the slave stations 21 to 40 has no slave station group that needs to be called as described above. An answer back command is issued to the slave station group G3 including the calling slave station.

In this way, unnecessary time slots can be reduced by not issuing an answer back command to a slave station group that does not include a calling slave station.

Further, as for the slave station group G3, since only the slave stations 42 and 43 receive a call, as shown in FIG. 2, a response is made in the time slots T2 and T3 in the slave station group G3. Since the master station A does not exist in the slave station group G3, when the master station A receives answerback information from the slave station 43, it shifts to an answerback command to the slave station group G20 to which the next call target slave station 400 belongs. You can also.

Thereby, the time slots corresponding to the slave stations 44 to 60 in the slave station group G3 can be omitted.

Second mode: This mode is applied when there is only one calling slave station in the slave station group, and only one slave station 400 to be called in the slave station group G20 is called. Therefore, in this case, the answer back information is transmitted using the first time slot T1 in the slave station group without using the time slots of all the slave stations 380 to 400 in the slave station group G20.

As a result, only one of the 20 time slots in the slave station group needs to be used, and 19 time slots can be reduced.

The above modes may be commanded separately or in combination.

〔Example〕

FIG. 3 shows a schematic configuration of a master station side and a slave station side of the wireless communication system according to the present invention. Side the receiver 13
And a data analysis unit 14, and the changeover switch 15 is switched by a control signal from the transmitter 12. Also,
The slave station 2 includes a receiver 21 and an answer back command analyzing unit 22 on the receiving side, and a signal generating unit 23 and a transmitter 24 on the transmitting side, and switches the changeover switch 25 according to a control signal from the transmitter 24. ing.

FIG. 4 shows the configuration of the answer command control unit 11 of the master station.
Reference numeral 17 denotes an answer-back command slave station group selecting unit for selecting a slave station group to which the slave station belongs based on the information of the selected station storage unit 16 and issuing an answer-back command to the slave station group, and 18 denotes a selected station storage unit.
An answerback command mode selection unit for selecting the above-mentioned mode based on the information of 16 slave stations, and a signal generation unit 23 for generating the above signals and transferring them to the transmitter.

The transmission frame of the master station output from the signal generator 23 has the format shown in FIG. 5, where BS is a bit synchronization signal section, FS is a frame synchronization signal data section, and SL is a frame synchronization signal data section.
CL is a selective call signal section for selectively calling each slave station. The code section corresponding to the slave station group number or individual slave station number, DATA is control of speaker open signal, end call signal and answer back command. Where multiple codes are inserted in parts,
The BCH is a redundant bit portion, which transmits a signal of a child station.

FIG. 6 shows an embodiment of the answer-back command analyzing unit 22 of the slave station B which analyzes the command from the master station A. Reference numeral 31 denotes a slave station group for extracting a slave station group number from the received data. A number extracting section, 32, a slave station group number comparing section, which determines whether or not the extracted slave station group number includes the slave station group number of the own station, 33
Is a slave station group number preset section in which the slave station group number of the own station is set in advance and sends the data to the slave station group number comparing section 32,
Reference numeral 34 denotes an answerback crag storage unit that stores an answerback flag, 35 denotes a control number analysis unit that extracts an answerback command from data, reads an answerback flag from the answerback storage unit 34, and sends an answer command, 36 Is an answerback information collection unit that collects data started by the control number analysis unit 35 and returned to the master station A by answerback, and 37 converts data collected by the answerback information collection unit into data codes and arranges them in order. An answerback data setting unit 38, an answerback timing generation unit 38, and an individual signal preset unit within a slave station group 39 for analyzing an answerback command and generating a time slot corresponding to an individual slave station number.

Next, the operation of the slave station will be described. When the receiver 21 of the slave station receives a transmission signal from the master station A, the received data is sent to the answer back command analyzer 22 of the slave station. The received data enters the slave station group number extracting section 31 and the slave station group number analyzing section 35, and the slave station group number extracting section 31 extracts a slave station group number from the input received data. The slave station group number extracted by the slave station group number extracting unit 31 is sent to the slave station group number comparing unit 32, and is compared with the slave station group number of the own station stored in the slave station group number preset unit 33. Here, the received data is sent to the control number analysis unit 35 only when it is determined that they match. The control number analysis unit 35 determines whether or not the control number is an answer back command from the received data, and further determines whether the answer back instruction is in the above-described mode or the mode.

In the mode, the answer back is returned in each time slot assigned to the individual slave station number stored in the slave station group individual number preset unit 39 (second mode).
In the case of time slots T1 to T20 in the case of slave stations 1 to 20 in the figure, and in the case of mode, regardless of the individual number in the slave station group,
Answer backing is performed in a fixed time slot (the first time slot T1 in the case of the slave station 400 shown in FIG. 2).

Accordingly, when the control number analysis unit 35 determines whether the mode is the answer back mode or the mode, the control number analysis unit 35 stores, as a flag, that the own station has been selected when there is a paging broadcast in order to obtain a time slot matching the mode command. The answerback flag storage unit 34 reads a flag indicating a time slot corresponding to the individual slave station number at the time of the mode command or a fixed time slot at the time of the mode command.If the flag is ON, the answerback information collection unit 36 is read. to start.

The answerback information collection unit 36 collects data to be returned to the master station A, and the collected data is assembled into a data transmission frame format by the answerback data setting unit 37. If the data from the control signal analyzer 35 is in answerback mode, the answerback timing generator 38 sets answerback data in a fixed time slot (T1 in the case of the slave station 400 in FIG. 2). The data from the section 37 is sent to the signal generating section. In the answerback mode, a time slot corresponding to the individual slave station number stored in the slave station group individual number preset section 39 (time slots T1 to T20 in the case of slave stations 1 to 20 in FIG. 2). Then, the data collected from the answer-back data setting unit 37 is sent to the signal generation unit 23. The signal generator 23 transmits this data to the master station A via the transmitter 24.

〔The invention's effect〕

As described above, according to the wireless communication system of the present invention, a plurality of slave stations are divided into groups including a small number of slave stations, and the slave stations are called for each slave station group. The time required for answer back when the answer back information from the station is divided into 20 × 20 groups of slave stations each having a time slot of 1 second can be shortened as follows.

A) When calling only the slave station 400: (1) Conventional 1sec + 400sec = 401sec (2) The present invention 1sec + 1sec = 2sec a) When calling only the slave station 1: (1) Conventional 1sec + 1sec = 2sec (2) Present invention 1sec + 1sec = 2) c) When sub-stations 1, 2, and 21 are called: (1) Conventional 1 sec + 1 sec = 22 sec (2) Present invention 1 sec + 2 sec + 1 sec + 1 sec = 5 sec Thus, as the number of sub-stations increases, the effect of time slot reduction becomes greater. growing.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram for explaining the principle of the wireless communication system according to the present invention, FIG. 2 is a time chart for explaining the principle of the wireless communication system according to the present invention, and FIG. FIG. 4 is a block diagram showing a configuration of a master station and a slave station in a wireless communication system according to the present invention; FIG. 4 is a block diagram showing an embodiment of an answer-back command control unit of the master station in a wireless communication system according to the present invention; FIG. 6 is a diagram illustrating a format of a transmission frame from a master station used in the present invention. FIG. 6 is a block diagram illustrating an embodiment of an answer back command analyzing unit of a slave station in a wireless communication system according to the present invention. FIG. 9 is a diagram for explaining the conventional method. In FIG. 1, A: master station, B: slave stations (slave stations 1 to 400), G1 to G20: slave station groups. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

(57) [Claims] 1. A wireless communication system in which a master station collects various information from a plurality of slave stations according to an answer back command, wherein the answer back command is used when the plurality of slave stations are further divided into a plurality of slave stations. When each slave station extracts the slave station group number of the answer back command and detects that it is the slave station group number of its own station, A wireless communication system characterized by transmitting answer back information in a time slot assigned to a wireless terminal. 2. The method according to claim 2, wherein the master station issues an answerback command to the next slave station group when collecting answerback information from the slave station regarding the last call of the slave station group requiring calling. 2. The wireless communication system according to claim 1, wherein: 3. When there is only one slave station in the slave station group number related to the call, the answer back command includes the slave station group number and the slave station number. 2. The wireless communication system according to claim 1, wherein when the answer back instruction is received and the slave station group number and the slave station number of the own station are detected, answer back information is transmitted in a first time slot.