JPS63161735A - Data collecting system - Google Patents

Abstract

PURPOSE:To contrive to reduce data collection time by forming a period of a transmission standby between a receptible state of a radio equipment and a transmittable state and switching the frequency of the oscillator during the period from the transmission frequency from the reception local state in a polling system using the synthesizer radio equipment. CONSTITUTION:When a radio equipment 20 of a slave station receives a data from a base station at a reception section 25 through a transmission/reception common antenna 23 and a transmission/reception changeover switch 24, the reception data is fetched in a MPU 11 and when a polling signal is detected, the frequency switching request is given at first and the MPU 21 changes the voltage given to a VCO 26 to change the oscillating frequency from the recep tion local to the transmission frequency. Then the MPU 11 decides it as the data sending timing based on the reception point of time of the polling signal as the reference, then a transmission request is given, the MPU 21 supplies power to the transmission section 27 to switch the switch 24 to the position of the sender side at the same time.

Description

[Detailed Description of the Invention] [Summary] The present invention provides a polling system in which some or all of the slave stations use a transmit/receive switching type synthesizer radio.
Data collection time is shortened by creating a transmission standby period between the radio's receivable state and transmittable state, and switching the oscillator frequency from the reception local to the transmission frequency within this period. .

[Industrial application field]

The present invention relates to an efficient data collection method for a polling system in which at least some of the slave station radios are synthesizer type.

[Conventional technology]

In an AVM (automotive vehicle monitoring) system for mobile stations such as taxis, a base station (master station) sends out a polling signal, and each mobile station (slave station) that receives the polling signal sequentially sends data at a unique timing. to be sent back. The data collection efficiency of this polling method is higher as the time from sending out the polling signal to receiving the data of the last time slot is shorter.

Figure 4 is a time chart of the conventional data collection method, and shows the time slot T in which multiple mobile stations 1 to n send back data.
1 to Tn are determined based on the polling signal of the master station, so data collision will not occur even if the same radio frequency is used. The data collection time T in this case is T=nt+α, where t is the time for one time slot, and α is the margin between the polling signal and the first time slot T+.

[Problem that the invention seeks to solve]

By the way, the method of using two types of dedicated wave crystal oscillators in recent radio equipment is expensive, and when changing the frequency, a new design is required, which requires a lot of man-hours. For this reason, there is a trend toward a synthesizer method using a VCO (voltage controlled oscillator). In this case, the shape,
If the mobile station's radio equipment is a TVCO-type transmitting/receiving switching type from a cost perspective, a locking time of several IQms is required until the frequency becomes stable when switching from receiving to transmitting, or vice versa. Conventionally, this lock time (1+ in Figure 4)
is included in the time slot, so the time t becomes longer. In other words, if the data sending time is t2, then t=
t + +t 2, so the data collection time T is T=n (t I + t 2) + cr ・
・・・－・－■. - As an example, n=10. t+=5
0ms.

When t2=100ms, it becomes T'-1.5s. This lock time t! A system using a radio without
In 2), T=nt2+α .

The present invention attempts to solve the above-mentioned problem by switching the oscillation frequency of the VCO to the transmitting frequency in advance when switching the synthesizer radio from the receiving state to the transmitting state.

[Means for solving problems]

The present invention provides a data collection method in which each slave station that receives a polling signal from a master station sequentially returns data at its own unique timing. During the period from when the wireless device transmits its own data, it switches the oscillator frequency from the receiving local frequency to the transmitting frequency and waits, and then when the timing for transmitting its own data arrives, it shifts the radio to the transmitting state. It is characterized by transmitting data using

[Effect]

A switchable transmitter/receiver type synthesizer radio can receive data when: ■ the transmitting/receiving antenna is connected to the receiving section, ■ power is supplied to the receiving section, and ■ the VCO is oscillating at the receiving local frequency. be.

Further, the radio device can transmit when (1) the transmitting/receiving antenna is connected to the transmitting section, (2) power is supplied to the transmitting section, and (2) the VCO is oscillating at the transmitting frequency.

Conventional transmission/reception switching is performed by simultaneously exchanging conditions ■ to ■ and conditions ■ to ■, but in the present invention, condition
and condition ■ are exchanged first, and then, when the own sending timing comes, condition ■■ and condition ■■ are exchanged. In this way, the transmission frequency is stabilized by the time it reaches its own transmission timing, so there is no need to include a lock time in each time slot.

FIG. 1 shows an example in which the lock time of each mobile station is set immediately after receiving a polling signal. In this case, when a polling signal is received, the VCO is immediately switched from the reception local frequency to the transmission frequency (■-■), and at each transmission timing, it is switched from the reception state (■■) to the transmission state (■■). ing.

This can be expressed as a state transition table as follows.

Table 1 Switching from reception to transmission is performed in the order of states 1-2-3-4, and switching from transmission to reception is performed in the order of states 4-3-2-1.

Time slots Tl, T2 . . . . are all reduced to just the data transmission time (t2 in FIG. 4). Therefore, the data collection time T becomes the equation 0 described above.

Note that if state 2 is delayed until just before state 4, state 3 becomes instantaneous (state 1 is extended by that amount).

〔Example〕

FIG. 2 is a block diagram showing an embodiment of the present invention, showing the configuration of a slave station using a synthesizer radio. This slave station consists of an AVMi terminal 10 and a synthesizer radio 20, and the microprocessor (MPU) 11 of the terminal 10 issues a frequency switching request and a transmission request to the MPU 21 of the radio 20. Communication with the base station can also be performed by voice using the microphone 12 and speaker 22, but below, the operation of data transmission by polling will be explained with reference to FIG.

When the radio device 20 is in a state in which reception is possible, the receiving unit (RX
) 25 receives data from the base station, the received data is transferred to M through the modem 13 and voice/data switching section 14.
Incorporated into PUII. When the MPU II detects a polling signal from this data, it first issues a frequency switching request as shown in Figure 3 (al).
U21 changes the voltage applied to the VCO 26 as shown in the figure (bl) to change the oscillation frequency from the reception local to the transmission frequency.After that, when the MPUII judges that it is its own data sending timing based on the time when the polling signal is received, Issue a transmission request.The MPU that received this transmission request
21 supplies power to the transmitter (TX) 27 and turns off the power to the receiver 25 according to the transmission/reception control signal, and at the same time switches the switch 24 to the transmitting side. In this state, MPUI
When I outputs the predetermined data, the transmission request is turned off. Upon detecting this, the MPU 21 turns off the power to the transmitter 27, turns on the power to the receiver 25, and switches the switch 24 to the receiving side. Then, after waiting for a frequency switching request from the MPUII side, the frequency of the VCO 26 is switched to the reception local.

Although the above-described embodiment assumes that all mobile station radios are of the synthesizer type, it is also possible to have a system configuration in which radios of a type that does not originally need to include a lock time in a time slot are mixed.

〔Effect of the invention〕

As described above, according to the present invention, there is an advantage that the overall data collection time can be shortened even if the slave station radio device is of a synthesizer type that requires a predetermined lock time for frequency switching.

[Brief explanation of the drawing]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 is a block diagram of a slave station showing an embodiment of the present invention, Fig. 3 is a flowchart showing the operation of Fig. 2, and Fig. 4 is a conventional data This is a time chart of the collection method. In the figure, 20 is a synthesizer receiver, 21 is a microprocessor, 23 is a transmitting/receiving antenna, 24 is a transmitting/receiving switch, 25 is a receiving section, 26 is a voltage controlled oscillator, and 27 is a transmitting section. Applicant Minoru Aoyagi, Patent Attorney, Fujitsu Ten Ltd.Principle of the Invention' 1LII1Figure 1Example 8 of the InventionHosbo +712Figure 2 1~■ C w#==Middle

Claims (1)

[Claims] In a data collection method in which each slave station that receives a polling signal from a master station returns data sequentially at its own unique timing, each slave station using a switchable transmitter/receiver type synthesizer radio receives the polling signal and then returns data. During the period until the data transmission timing is reached, the oscillator frequency is switched from the reception local frequency to the transmission frequency and waits, and then when the own data transmission timing is reached, the radio is shifted to the transmission state and the data is transmitted. A data collection method characterized by: