JP2005277500A - Wireless transmitter and device for determining existence - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless transmitter capable of transmitting its identification signal while avoiding collision against other identification signal even if several tens of wireless transmitter exist in the same region. <P>SOLUTION: A radio tag 10 determines a quiescent time T using at least two digits of an identification number k consisting of a plurality of digits and transmits an identification signal I repeatedly while interposing the quiescent time T between. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless transmitter and a presence / absence determining device, and more particularly, to a wireless transmitter that repeatedly transmits a self-identification signal with a pause time, and even if several tens are present in the same region, other identification is performed. The present invention relates to a wireless transmitter capable of transmitting a self-identification signal while avoiding a collision with a signal, and a presence / absence determining device for determining presence / absence of the wireless transmitter.

Conventionally, when a response signal for a transmission signal cannot be received, retransmission of the transmission signal with a pause time calculated from one digit of the identification number selected according to the number of retransmissions is repeated until the response signal can be received. Wireless transmission / reception devices (“wireless transmission / reception devices”) are known (for example, see Patent Document 1).
On the other hand, a wireless transmitter (“sender”) that repeatedly transmits an identification signal with a pause time changed in a pseudo-random manner is known (see, for example, Patent Document 2).

JP-A-6-276180 (FIG. 2) Japanese translation of PCT publication No. 2003-500985 ([0011] [0023] [0037])

  In the wireless transmission / reception apparatus (“wireless transmission / reception apparatus”), the pause time is calculated using only one digit of the identification number. However, in many cases, the wireless transceivers used in the same area are assigned serial numbers with an identification number. For example, when an identification number is assigned with a hexadecimal serial number, the least significant side is assigned every 17th unit. The value of the first digit is the same, and the consecutive 16 units have the same value of the second digit on the lowest side. For this reason, when several tens of devices are present in the same area, there is a problem that the existence probability of the wireless transmission / reception apparatus having the same pause time is increased, and the probability of collision is increased. Further, since a reception function for receiving the response signal is required, there is a problem that the configuration of the apparatus is complicated.

  On the other hand, in the wireless transmitter (“sender”), the pause time is changed pseudo-randomly. However, as the number of wireless transmitters existing in the same region increases, the existence probability of wireless transmission / reception devices having the same random value, that is, the same pause time increases, and the probability of collision increases.

  Accordingly, an object of the present invention is to determine a radio transmitter that can transmit a self-identification signal while avoiding a collision with other identification signals even if several tens of them are present in the same region, and whether or not these radio transmitters exist. The object is to provide an existence determination device.

In a first aspect, the present invention determines an idle time T based on at least two digits of an identification signal transmission means for transmitting an identification signal I and an identification number k consisting of a plurality of digits corresponding to the identification signal I. There is provided a radio transmitter comprising transmission control means for repeatedly operating the identification signal transmission means with a pause time T interposed therebetween.
In the wireless transmitter according to the first aspect, the pause time T is determined using at least two digits of the identification number k consisting of a plurality of digits. For example, when an identification number is assigned by a hexadecimal serial number, the lowest two-digit value is the same at the 257th unit from the beginning. Therefore, even if several tens of vehicles are present in the same area, all the pause times T are different, and the self-identification signal can be transmitted while avoiding a collision with other identification signals.

In a second aspect, the present invention provides an idle time based on identification signal transmitting means for transmitting an identification signal I, at least two digits of an identification number k consisting of a plurality of digits corresponding to the identification signal I, and the number of transmissions n. There is provided a radio transmitter comprising: a transmission control means for determining T and repeatedly operating the identification signal transmission means with the pause time T interposed therebetween.
In the radio transmitter according to the second aspect, the pause time T is determined using at least two digits of the identification number k consisting of a plurality of digits. For example, when an identification number is assigned by a hexadecimal serial number, the lowest two-digit value is the same at the 257th unit from the beginning. Therefore, even if several tens of vehicles are present in the same area, all the pause times T are different, and the self-identification signal can be transmitted while avoiding a collision with other identification signals. Furthermore, since the pause time T is also changed depending on the number of transmissions n, even if there are more than several tens of vehicles in the same region, collision with other identification signals can be avoided and the self-identification signal can be transmitted.

In a third aspect, the present invention provides the wireless transmitter configured as described above, wherein the transmission control means includes K ₁ , K _{2 in} the first digit to the J (≧ 2) digit on the least significant side of the identification number k. , ..., K _J and when the digit weights are w ₁ , w ₂ , ..., w _J ,
W _k = K ₁ × w ₁ + K ₂ × w ₂ + ... + K _J × w _J
And the basic pause time is T0, the unit change time is τ, the maximum change time is Tdmax, the remainder obtained by dividing a by b is mod (a / b), and the integer part of the quotient obtained by dividing a by b When int (a / b) is set, the n-th (= 1, 2,...) pause time T (k, n) is
T (k, n) = T0 + (− 1) ^{mod ((k + 1) / 2) × mod ((n + 1) / 2)} × (W _k × τ) × mod (n / (int (Tdmax / (W _k × τ)))
According to the present invention, a wireless transmitter is provided.
In the radio transmitter according to the third aspect, the pause time T (k, n) is determined according to the following rules.
Rule 1: If the identification number k is an odd number, the pause time increases by the amount of change “W _k · τ” determined by the identification number k as the number of transmissions n increases. However, it changes cyclically so that the increase in the pause time does not exceed the maximum change time Tdmax.
Rule 2: If the identification number k is an even number, when the number of transmissions n is an odd number, the pause time increases by “W _k · τ” as the number of transmissions n increases, and the number of transmissions n is an even number. When the number of transmissions n increases, the pause time decreases by “W _k · τ” which is determined by the identification number k. However, the increase or decrease of the pause time changes cyclically so as not to exceed the maximum change time Tdmax.
Since the pause time changes in various patterns as described above, even if a larger number than a few tens are present in the same region, collision with other identification signals can be avoided and the self-identification signal can be transmitted.

In a fourth aspect, the present invention provides a wireless transmitter characterized in that w ₁ > w _J in the wireless transmitter configured as described above.
When the identification number k is assigned sequentially to wireless transmitters existing in the same area, the higher digit of the identification number k is more likely to have the same digit value.
Therefore, in the wireless transmitter according to the fourth aspect, the weight w ₁ for the least significant digit of the identification number k is made the same by making it greater than the weight w _J for the most significant digit used for determining the pause time T. The difference in the downtime of the wireless transmitters existing in the area is increased.

In a fifth aspect, the present invention provides a wireless transmitter characterized in that, in the wireless transmitter configured as described above, the transmission time S of the identification signal I changes corresponding to the identification number k.
In the radio transmitter according to the fifth aspect, since the transmission time S of the identification signal I also changes corresponding to the identification number k, the transmission interval (= transmission time S + pause time T) changes in a very diverse pattern. Even if a larger number than a few tens are present in the same area, collision with other identification signals can be avoided and the self-identification signal can be transmitted.

In a sixth aspect, the present invention provides a wireless transmitter having the above-described configuration and a plurality of wireless transmitters each corresponding to a different identification number, and for receiving the identification signal from the wireless transmitter. And a determination unit that determines that the wireless transmitter corresponding to the received identification signal exists in a reception area of the wireless reception unit if the identification signal is normally received by the wireless reception unit. The presence / absence determination device is provided.
In the presence / absence determining device according to the sixth aspect, since the wireless transmitter having the above-described configuration is used, even if several tens of wireless transmitters exist in the same region, collision of identification signals can be avoided, and each wireless transmission The presence or absence of the machine can be determined with certainty.

According to the wireless transmitter of the present invention, even if several tens of units are present in the same area, a collision with other identification signals can be avoided and a self-identification signal can be transmitted.
According to the presence / absence determination device of the present invention, even if several tens of wireless transmitters exist in the same area, the presence / absence of each wireless transmitter can be reliably determined.

  Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited thereby.

FIG. 1 is a configuration diagram illustrating a wireless tag 10 according to the first embodiment.
The wireless tag 10 includes a microprocessor 3 including a storage unit 1 and a transmission control unit 2 that store an identification number k, a radio wave transmission circuit 4 that transmits an identification signal I output from the microprocessor 3 by radio waves, A button battery 5 for supplying power to the processor 3 and the radio wave transmission circuit 4 is provided.

FIG. 2 is an exemplary diagram of the identification number k.
The identification number k is a hexadecimal 8-digit numerical value. The first digit of the least significant and _{K 1,} a second digit and _{K 2,} the third digit and _{K 3,} the fourth digit and _{K 4,} the 5 digit and _{K 5, K 6} a 6 digit and then, the 7 digit and _{K 7,} an 8-digit and _{K 8.}

FIG. 3 is a flowchart showing an identification signal transmission control process executed by the transmission control unit 2.
In step P <b> 1, an identification signal I is created based on the identification number k stored in the storage unit 1 and stored in the storage unit 1.

FIG. 4 is an exemplary diagram showing the length of the identification signal I (= transmission time S).
For example, the transmission time S of the identification signal I having the identification number “00000001” is 2800 [μs]. Further, the transmission time S of the identification signal I having the identification number “00000002” is 2840 [μs].

Returning to FIG. 3, in step P2, the first digit to the J (≧ 2) digit of the identification number k are set to K ₁ , K ₂ ,..., K _J , and the digit weights are w ₁ , w ₂ , ..., w _J
W _k = K ₁ × w ₁ + K ₂ × w ₂ + ... + K _J × w _{J
Is used} to calculate the change weight Wk.

The value of J should be set to J ≧ N if the lowest digit N digits of the identification number k is sufficient when the identification number k is assigned consecutively to a plurality of wireless tags 10 used in the same area. preferable. For example, if the number of wireless tags 10 used in the same area is 256 and the identification number k is assigned with a hexadecimal serial number, for example, “xxxx001” to “xxxx100” are obtained, and the lowest number of the identification number k Since three digits are sufficient, it is preferable that J ≧ 3.
The values of the digit weights w ₁ , w ₂ ,..., W _J are set to the least significant side in consideration of the fact that a plurality of wireless tags 10 used in the same area are usually assigned serial numbers and identification numbers k. It is preferable to increase the digit weight as it is closer.
For example, J = 4, w ₁ = 5, w ₂ = 3, w ₃ = 2 and w ₄ = 1.

  In step P3, the transmission count is initialized to n = 1.

In step P4, the basic pause time is T0, the unit change time is τ, the maximum change time is Tdmax, the remainder obtained by dividing a by b is mod (a / b), and the integer part of the quotient obtained by dividing a by b is When int (a / b), the n-th pause time T (k, n) is
T (k, n) = T0 + (− 1) ^{mod ((k + 1) / 2) × mod ((n + 1) / 2)} × (W _k × τ) × mod (n / (int (Tdmax / (W _k × τ)))
Calculated by

As shown in FIG. 5, J = 4, w ₁ = 5, w ₂ = 3, w ₃ = 2 and w ₄ = 1, T 0 = 1000 [ms], τ = 4 [ms], Tdmax = 200 [ ms] and an identification number k = 00000001,
W _k = 1 × 5 + 0 × 3 + 0 × 2 + 0 × 1 = 5
W _k × τ = 5 × 4 = 20
int (Tdmax / (W _k × τ)) = int (200/20) = 10
mod ((k + 1) / 2) = mod ((1 + 1) / 2) = 0
So,
T (1, n) = 1000 + 20 × mod (n / 10)
And
T (1,1) = 1020
T (1,2) = 1040
T (1,3) = 1060
T (1,4) = 1080
T (1,5) = 1100
T (1,6) = 1120
T (1,7) = 1140
T (1,8) = 1160
T (1,9) = 1180
T (1,10) = 1000
T (1,11) = 1020
T (1,12) = 1040
T (1,13) = 1060
T (1,14) = 1080
...
It becomes.

Further, as shown in FIG. 6, if the identification number k = 00000002,
W _k = 2 × 5 + 0 × 3 + 0 × 2 + 0 × 1 = 10
W _k × τ = 10 × 4 = 40
int (Tdmax / (W _k × τ)) = int (200/40) = 5
mod ((k + 1) / 2) = mod ((2 + 1) / 2) = 1
So,
T (2, n) = 1000 + (− 1) ^{mod ((n + 1) / 2)} × 40 × mod (n / 5)
If n is an odd number,
T (2, n) = 1000 + 40 × mod (n / 5)
If n is an even number,
T (2, n) = 1000−40 × mod (n / 5)
And
T (2,1) = 1040
T (2,2) = 920
T (2,3) = 1120
T (2,4) = 840
T (2,5) = 1000
T (2,6) = 960
T (2,7) = 1080
T (2,8) = 880
T (2,9) = 1160
T (2,10) = 1000
T (2,11) = 1040
T (2,12) = 920
T (2,13) = 1120
T (2,14) = 840
...
It becomes.

Returning to FIG. 3, in step P5, the process waits for a pause time T (k, n).
In step P6, the identification signal I is transmitted from the radio wave transmission circuit 4.
In step P7, the transmission count n is incremented by one. Then, the process returns to Step P4.

FIG. 7 is a configuration diagram illustrating the presence / absence determination device 100 according to the first embodiment.
The presence / absence determination device 100 stores a serial number identification number k, and repeatedly transmits an identification signal I representing the identification number k with a pause time T (k, n) interposed therebetween. .., 10-2,..., Radio receiver 20 for receiving the identification signal I from the radio tag 10 in the reception area A, and if the radio receiver 20 has successfully received the identification signal I And a determination processor 30 that determines that the wireless tag 10 corresponding to the identification signal I that has been normally received exists in the reception area A.

  The reception area A is, for example, a work place, and the wireless tag 10 is built in, for example, a worker's name plate. Then, presence / absence of more than tens of workers can be suitably determined by the presence / absence determination device 100.

  The reception area A is, for example, a store, and the wireless tag 10 is built in, for example, a product label. Then, the presence / absence determining device 100 can suitably determine the presence / absence of more than tens of items.

  The wireless transmitter and presence / absence determination device of the present invention can be used to determine the presence / absence of individual personnel and articles in a state where there are several tens or more personnel and several tens or more articles in a predetermined location.

1 is a configuration diagram illustrating a wireless tag according to Embodiment 1. FIG. It is an illustration figure of an identification number. It is a flowchart which shows an identification signal transmission control process. It is an illustration figure which shows a response | compatibility with an identification number and transmission time S. FIG. It is explanatory drawing which shows the relationship between the frequency | count n of transmission in the radio | wireless tag of the identification number k = 1, and idle time T (k, n). It is explanatory drawing which shows the relationship between the frequency | count n of transmission in the radio | wireless tag of the identification number k = 2, and idle time T (k, n). 1 is a configuration diagram illustrating a presence / absence determining device according to Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Memory | storage part 2 Transmission control part 3 Microprocessor 4 Radio wave transmission circuit 5 Button battery 10, 10-1, ... Wireless tag 20 Radio | wireless receiver 30 Judgment processor 100 Existence determination apparatus A Reception area

Claims (6)

  An identification signal transmitting means for transmitting the identification signal I, and a pause time T determined based on at least two digits of the identification number k consisting of a plurality of digits corresponding to the identification signal I, and the identification signal transmission across the pause time T A wireless transmitter comprising transmission control means for repeatedly operating the means.   A pause time T is determined on the basis of an identification signal transmitting means for transmitting the identification signal I, at least two digits of the identification number k consisting of a plurality of digits corresponding to the identification signal I, and the number of times of transmission n, and the pause time T is sandwiched. And a transmission control means for repeatedly operating the identification signal transmission means. 3. The wireless transmitter according to claim 1, wherein the transmission control unit includes K ₁ , K ₂ ,..., The first digit to the J (≧ 2) digit on the least significant side of the identification number k. and K _J, the digit weights _{w 1,} w 2, ..., when the _{w J,}
W _k = K ₁ × w ₁ + K ₂ × w ₂ + ... + K _J × w _J
And the basic pause time is T0, the unit change time is τ, the maximum change time is Tdmax, the remainder obtained by dividing a by b is mod (a / b), and the integer part of the quotient obtained by dividing a by b When int (a / b) is set, the n-th (= 1, 2,...) pause time T (k, n) is
T (k, n) = T0 + (− 1) ^{mod ((k + 1) / 2) × mod ((n + 1) / 2)} × (W _k × τ) × mod (n / (int (Tdmax / (W _k × τ)))
A wireless transmitter characterized by: The wireless transmitter according to claim 3, wherein w ₁ > w _J is satisfied.   5. The wireless transmitter according to claim 1, wherein a transmission time S of the identification signal I changes corresponding to the identification number k. 6.   A plurality of wireless transmitters according to any one of claims 1 to 5, each corresponding to a different identification number, and for receiving the identification signal from the wireless transmitter And a determination unit that determines that the wireless transmitter corresponding to the received identification signal exists in a reception area of the wireless reception unit if the identification signal is normally received by the wireless reception unit. A presence / absence determination device comprising:

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