JPH1175244A - Portable terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the distance between portable terminals even when the transceiver function of PHS is used by generating reference time on the basis of the standard time obtained by receiving a standard radio wave, measuring the delay time of a radio wave from another portable terminal on the basis of the reference time, and calculating the distance between the portable terminals on the basis of the delay time. SOLUTION: A timer part 21 manages the reference time on the basis of the standard radio wave from an antenna B20. For distance measurement, a signal processing control circuit 16 outputs time data showing the timing of transmission included in a received wave to a counter 15 and a UW detecting circuit 14 processes the 1st timing where the UW signal of the received signal starts as reception timing and outputs it to the counter 15. The counter 15 counts the reception time from the reception timing and reference time and counts the delay time based upon radio wave propagation from the difference between the time data representing the timing of transmission and the reception time. Consequently, the accurate relative distance can be calculated from the delay time having less error according to the precise reference time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for controlling a portable terminal used in a wireless communication system capable of measuring a distance between portable terminals performing wireless communication with each other.

[0002]

2. Description of the Related Art Conventionally, a radio communication system capable of measuring a distance between a base station and a portable terminal performing radio communication with each other using a TDMA-TDD (Time Division Multiple Access-Time Division Bidirectional Transmission) system. In Japanese Patent Application Laid-Open No. H10-157, the delay time of the radio wave is measured by the base station based on the reference frequency, and the distance is calculated based on the measured delay time.

For example, when the reference frequency is 19.2 MHz as in the example of a PHS (simplified mobile phone),
A delay time of 0.052 μs, which is one cycle, can be determined. Therefore, the relative difference between the reference times generated by two similar portable terminals is ± 0.026 μs. When measuring a short distance, it is desirable to perform time management with higher accuracy.

The propagation speed of radio waves in air is 1 μs
Is about 300 m. Therefore, in the method of measuring the delay time of the round trip distance and calculating the mutual linear distance (one-way distance), the above-mentioned discriminable delay time of 0.052 μs indicates that the round trip distance between the base station and the portable terminal is about 15 It is a distance of 0.6 m, and in principle a measurement of up to about 7.8 m is possible with a one-way distance, that is, a distance from each other.

However, in the measurement of the distance between the PHS base station and the portable terminal, an arithmetic circuit for distance measurement is provided in the base station equipment, and the number of set points is limited within the PHS service area. Can be For this reason, it cannot be used when the area is out of the PHS service area such as a mountain or a leisure facility area on the coast.

[0006]

As described above, in the method in which the arithmetic processing is performed on the base station side, the distance cannot be measured outside the PHS service area. Therefore, the present invention has been made in order to solve such a problem.
It is an object of the present invention to provide a portable terminal capable of measuring a distance even when the transceiver function of the HS is used. It is still another object of the present invention to provide a mobile terminal capable of measuring a delay time with high accuracy because a reference time configured using the standard time is used.

[0007]

According to a first aspect of the present invention, there is provided a portable terminal, comprising: a clock means for generating a reference time based on a standard time obtained by receiving a standard radio wave; Measuring means for measuring the delay time of the radio wave from the portable terminal, time notifying means for notifying the measurement start time to another portable terminal to measure the delay time, and based on the measured delay time of the radio wave. Distance calculating means for calculating the distance between the portable terminals.

In the portable terminal of the second invention, a clock means for generating a reference time based on the standard time obtained by receiving the standard radio wave, and a radio wave from another portable terminal based on the reference time Measuring means for measuring the delay time of the mobile station, time notifying means for notifying the measurement start time to another mobile terminal, measuring condition notifying means for notifying the other mobile terminal of the measurement condition and the measurement result display condition, and the measured radio wave. And distance calculating means for calculating the distance between the portable terminals based on the delay time.

In the portable terminal of the third invention, a clock means for generating a reference time based on the standard time obtained by receiving the standard radio wave, and a radio wave from another portable terminal based on the reference time. Measuring means for measuring the delay time of the mobile terminal, time notifying means for notifying the measurement start time for measuring the delay time, and distance calculating means for calculating the distance between the portable terminals based on the measured delay time of the radio wave. And a calibration means for calibrating the measurement distance.

In the portable terminal according to a fourth aspect of the present invention, a clock means for generating a reference time based on a standard time obtained by receiving a standard radio wave, and a radio wave from another portable terminal based on the reference time. Measuring means for measuring the delay time of the mobile phone, time notifying means for notifying another mobile terminal of the measurement start time for measuring the delay time, and determining the distance between the mobile terminals based on the measured radio wave delay time. It has a distance calculating means for calculating and a relative movement calculating means for calculating the movement state of the other party.

In the portable terminal according to a fifth aspect of the present invention, a clock means for generating a reference time based on a standard time obtained by receiving a standard radio wave, and a radio wave from another portable terminal based on the reference time. Measuring means for measuring the delay time of the mobile terminal, time notifying means for notifying the measurement start time for measuring the delay time, and distance calculating means for calculating the distance between the portable terminals based on the measured delay time of the radio wave. And display means for displaying the history of change in the distance of the portable terminal on a display.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a configuration diagram for explaining the operation of the mobile terminal according to the first embodiment. In FIG. 1, 1 is a microphone, 2 is a signal synthesis circuit, 3 is a QPSK modulation circuit, 4 is a DA conversion circuit, 5 is a transmission circuit, 6 is a transmission / reception switching circuit, 7
Is an antenna A, 8 is a receiving circuit, 9 is an AD conversion circuit, 10
Is a detection circuit, 11 is a receiver, 12 is a signal separation circuit, 1
3 is a UW generation circuit, 14 is a UW detection circuit, 15 is a counter, 16 is a signal processing control circuit, 17 is an operation unit, 18 is a storage unit, 19 is a display unit, 20 is an antenna B, and 21 is a clock unit.

In FIG. 1, first, during a voice call, voice is converted into an electric signal by a microphone 1, differentially phase-modulated by a QPSK modulation circuit 3 through a signal synthesis circuit 2, and converted into a digital signal by a DA conversion circuit 4. The signal is converted into an analog signal, converted into a harmonic signal by the transmission circuit 5, further amplified to a predetermined output, and radiated into the air from the antenna A: 7 as a transmission wave via the transmission / reception switching circuit 6.

The received wave is received by an antenna A: 7, is subjected to low-noise amplification by a receiving circuit 8 via a transmission / reception switching circuit 6, is converted to a predetermined low frequency, and is converted from an analog signal to a digital signal by an AD conversion circuit 9. The signal is detected by a detection circuit 10 and converted from an electric signal to a sound by a receiver 11 via a signal separation circuit 12.

On the other hand, in the figure, when measuring the distance between portable terminals, time information from the clock unit 21 is output as time data to the signal synthesizing circuit 2 via the signal processing control circuit 16 and is included in the transmission wave as information. And radiate into the air.

The received wave at the time of measuring the distance between the portable terminals includes time data as information, is recognized by the signal processing control circuit 16 via the signal separation circuit 12, and is sent to the counter 15 as time data representing the timing at the time of transmission. Is output.

Here, the UW represented by the UW generation circuit 13
The (unique word) data is synthesized by the signal synthesizing circuit 2 with the audio electric signal, and becomes the synchronizing signal data of the transmission wave. The data indicating the timing at the time of transmission is a time indicating the first timing at which the UW signal starts.

The UW data, which is a synchronization signal of the received wave separated by the signal separation circuit 12, is subjected to timing processing by the UW detection circuit 14. The processed reception timing and time information from the clock unit 21 are input to the counter 15 as time data via the signal processing control circuit 16.
It is counted as the reception time. The data indicating the timing at the time of reception is a time indicating the first timing at which the UW signal starts.

Furthermore, the counter 15 counts the difference between the time data representing the timing at the time of transmission and the time data representing the timing at the time of reception, and counts the delay time based on radio wave propagation. The delay time of the radio wave is output to the signal processing control circuit 16 and used for calculating the distance.

For example, when the relative distance is measured by transmitting from the portable terminal A and receiving by the portable terminal B, the counter 15 of the portable terminal B uses the transmission timing time as information in the received wave and the UW signal of the received wave. Then, the difference between the two is counted from the reception timing time processed from step (1) and is used as the radio wave delay time.

The signal processing control circuit 16 controls the measurement of the delay time of the radio wave by the counter 15 and calculates the distance, and also controls the transmission and reception switching timing of the transmission / reception switching circuit 6. Also, under the control of the operation unit 17, recognition of an input signal from a key button, data input to and readout from the storage unit 18, and the like are performed, and predetermined characters are displayed on the display unit 19.

The operation unit 17 includes key buttons and the like, and is used to perform an operation for setting the operation of the portable terminal for distance measurement. The storage unit 18 includes a nonvolatile memory and a backup power supply. The display unit 19 includes an LCD display and an LCD driver, and is used to store setting conditions for measurement, measurement data, distance calculation data, and the like. It is for confirming, confirming the measurement distance, and confirming a change in the measurement distance.

The clock section 21 manages a reference time based on a standard radio wave received from the antenna B: 20 and inputs the reference time to the control circuit 16 as a reference time. Means for knowing the standard time include short-wave standard radio waves, long-wave / ultra-long-wave standard radio waves, GPS (Global Positioning System), and stabilized TV signals. The desired precision is selected from these and used.

The reception of the standard time is not always possible but may be intermittent reception. The reference time is managed by a reference transmitter included in the mobile terminal, and the standard time is used as a means for periodically calibrating the reference time, thereby improving the absolute accuracy of the time.

Hereinafter, the communication format will be described. FIG. 2 is a configuration diagram of a physical slot defined in the standard RCR: STD-28 of the second generation cordless telephone system. In FIG. 2, in the two-way communication, one frame (5 ms) is divided into a 2.5 ms reception time zone like a 2.5 ms transmission time zone t1 by time division, and the transmission time zone is further divided into four transmission time slots. T
1 to T4, and the reception time zone includes four reception time slots R1 to R4. One pair of transmission and reception
It consists of a transmission time slot Ti and a reception time slot Ri. i is 1 to 4, from which four communication channels are configured.

Next, the configuration of one time slot will be described. FIG. 3 shows the configuration of one control physical slot. In FIG. 3, one time slot (0.6
25 ms) is composed of 240 bits. One bit is 2.6 μs. This means that one bit when calculated from the transmission rate of 384 kbps in the wireless section specified by RCR: STD-28 is equal to about 2.6 μs.

In the slot, 4-bit R, 2-bit SS, 62-bit PR, 32-bit UW, 4-bit CI, 42-bit destination identification code, 28-bit calling identification code, 4-bit I / O code , 16-bit CRC, and 16
Bit (41.7 μs) guard bit GB.

FIG. 4 shows the structure of one communication physical slot. In FIG. 4, one time slot (0.6
25 ms) is composed of 240 bits. In the slot, R of 4 bits, SS of 2 bits, P of 62 bits
R, 32-bit UW, 4-bit CI, 16-bit SA, 160-bit I, 16-bit CRC, and 16-bit (41.7 μs) guard bit GB.

The guard bit GB is a time zone provided so that the time slots of the portable terminals do not collide with each other due to the delay time during radio wave propagation.

FIG. 5 shows a state where the mutual distance between the portable terminal A and the portable terminal B is a distance D. Hereinafter, the case of D = 0 and D =
Communication timing in the case of DD will be described.

FIG. 6 is a transmission / reception timing chart when D = 0. Here, the mobile terminal A is connected to the mobile terminal B.
Shall be sent to

FIG. 6A shows the reference time, and the time data follows T1, T2, T3,... At regular intervals. This reference time is a time common to the mobile terminals A and B, and is managed with high accuracy by both mobile terminals.

FIG. 6B shows that the portable terminal A transmits the transmission data D1 to the portable terminal B at the transmission timing T1. The transmission data includes a transmission time as transmission timing information.

FIG. 6C shows that portable terminal A transmits transmission data D
1 at the transmission timing T1 and at the same time
Indicates that the transmission data D1 transmitted by the mobile terminal A at the transmission timing T1 has been received as the reception data D2.

From the continuity of the communication, the portable terminal A and the portable terminal B communicate continuously every frame (5 ms). However, the measurement may be completed once or may be performed a plurality of times. In the case of performing a plurality of measurements, the portable terminal B takes 2.5 ms × n (n = 1, 3,
5) After that, the transmission data is transmitted.

FIG. 6B shows that the portable terminal A transmits the transmission data D
4 at the transmission timing (T1 + 2.5 ms × n), and at the same time the portable terminal A transmits the transmission timing (T1 + 2.5
It indicates that the transmission data D4 transmitted by the mobile terminal B has been received as the reception data D3 in ms × n. Note that the delay time of the radio wave can be measured by simply receiving the transmission data transmitted from the mobile terminal A by the mobile terminal B.

In FIG. 6B, the data is transmitted from the portable terminal A,
The figure shows a state in which the mobile terminal B receives the data, further transmits the mobile terminal B, and receives the data from the mobile terminal A. When the distance D between the mobile terminals is D = 0, the time from when the mobile terminal A transmits the transmission data D1 to when the reception data D4 is received is:
It is 2.5 ms × n. That is, the UW signal of the portable terminal A shown in FIG.
Received with a delay of ms × n.

FIG. 7 is a transmission / reception timing chart when D = DD. FIG. 7A shows a reference time, which is continued as TD1, TD2, TD3,. The reference times of the mobile terminals A and B are managed with high accuracy.

FIG. 7B shows that portable terminal A transmits transmission data DD1 to portable terminal B at transmission timing TD1. The transmission data includes a transmission time as transmission timing information.

FIG. 7C shows that portable terminal A transmits transmission data D
This indicates that the portable terminal B has received the transmission data DD1 transmitted by the portable terminal A at the reception timing (TD1 + τ1) as the reception data DD2 when D1 was transmitted at the transmission timing TD1. Also in this case, the portable terminal B transmits the transmission data DD4 2.5 ms × n after the reception timing (TD1 + τ1).

FIG. 7B shows that portable terminal B transmits transmission data D
D4 at the transmission timing (TD1 + τ1 + 2.5ms ×
n), the mobile terminal A sets the timing (TD1 +
(τ1 + 2.5 ms × n + τ2) indicates that the transmission data DD4 transmitted by the portable terminal B has been received as the reception data DD3. Therefore, the time from when the mobile terminal A transmits the transmission data DD1 to when it receives the reception data DD4 is 2.5 ms × n + τ1 + τ2. That is, the UW signal of the portable terminal A shown in FIG.
As shown in (E), the signal is received with a delay of 2.5 ms × n + τ1 + τ2. Note that GB in FIGS. 6 and 7 indicates a guard bit.

The delay time of a radio wave is measured by the following method. When the radio wave is transmitted from the mobile terminal A to the mobile terminal B, the mobile terminal B can measure the propagation time of the radio wave only by receiving the transmission wave from the mobile terminal A to perform the operation with the minimum number of steps. That is, the counter 15 of the mobile terminal B includes
The transmission timing information transmitted by the mobile terminal A, the reception timing information received by the mobile terminal B, and the current time information are input. Therefore, the mobile terminal B counts the reception timing time information from the reception timing information and the current time information, and counts the difference between the two from the transmission timing time information and the reception timing time information,
The delay time of the radio wave can be counted as τ.

Next, the propagation time and propagation distance of a radio wave will be described. The propagation speed of radio waves is about 3 × 10 ⁸ (m /
s), the distance D between the mobile terminal A and the mobile terminal B
(M) is represented by the following equation. D (m) = 3 × 10 ⁸ (m / s) × τ (μs) × 10 ^-6
= 300 × τ

As shown in FIG. 4, the guard bit is 16 bits.
In the PHS, the measurable time of the delay time of the radio wave is 41.7 μs. When this is converted into the maximum measurable distance, Dmax = 300 × 41.7 = 12,
510 (m). However, the distance actually used is about 300 m or less as a range where radio waves can reach in the transceiver mode using the PHS.

The counter 15 counts the radio wave delay time and outputs the result to the signal processing control circuit 16. The signal processing control circuit 16 calculates the distance between the portable terminals based on the delay time, and displays the distance on the display unit 19.

Here, the time data serving as the basis of the reference time data will be described. The reference frequency of the mobile terminal is 1
9.2 MHz, the reference clock signal based on this frequency is about 0.052 μs, and the time accuracy is about ±
0.026 μs. The measurement error of the distance between the portable terminals due to the accuracy of the reference clock signal is ± 300 ×. 026 =
± 7.8 (m).

On the other hand, the accuracy of the standard time is about 100 μs for the standard radio wave, and about 1 μs for the stabilized TV signal.
μs, GPS (Global Positioning System), TV color subcarrier phase, etc.
μs is obtained. Of these, those that can be used to construct the reference clock signal are methods using GPS or television color subcarrier phases, and are therefore used.

Therefore, the deviation of the reference clock managed between the portable terminals can be considered to be about ± 0.005 μs if the calibration is performed periodically using the standard time. , 300 × 0.005 = 1.
This is about 5 (m), which is sufficient measurement accuracy.

When the distance is measured, it is necessary for both portable terminals to determine the measurement conditions and the result of the measurement using either portable terminal. First, regarding the measurement conditions,
From which mobile terminal performs the first transmission, determines whether the mobile terminal that has received the transmission wave retransmits, what to do with the value of n in FIG. 7 when retransmitting, how many times the measurement is performed, etc. There is a need. Whether the measurement result is displayed on only one mobile terminal or both terminals is displayed. The conditions necessary for these measurements can be transmitted as information before the start of the measurements.

Next, in a radio circuit, a transmitted signal is delayed in some circuit components such as a filter. The above-described propagation time of a radio wave includes a delay due to propagation in space and a delay due to transmission through a wireless circuit. Therefore, if the distance is converted from the measured delay time only by the speed of the radio wave propagating in the air, an error occurs. Therefore, the mobile terminal is calibrated to correct this error. Assuming that the actual distance is, for example, D = 300 (m), the correction value of the delay time is obtained using three mobile terminals A, B, and C.

The distance measured using any two of the three portable terminals is represented by D _AB (m), D _BC (m), and D _CA
(M). Furthermore, the delay time in air is given by τ _A (μ
Then, the following relational expression is obtained. _{D AB = 300 × (τ A} + Δτ A + Δτ B) D BC = 300 × (τ A + Δτ B + Δτ C) D CA = 300 × (τ A + Δτ C + Δτ A) _{where, Δτ A (μs), Δτ} B (Μs), Δτ _C (μ
s) is a correction value of the mobile terminal A, the mobile terminal B, and the mobile terminal C, respectively. Since τ _A is the delay time of radio waves in the air, the distance is 300 (m) to 1 (μs). D
_AB, D _BC, knowing the _{D CA, Δτ A, Δτ B} , Δτ C can be calculated.

Since the delay caused by the radio circuit of a specified portable terminal is always constant, Δτ _A , Δτ _B , and Δτ _C can be calculated once and the same values can be used thereafter.
To correct the delay time, that is, to calibrate the mobile terminal, if a mobile terminal having a known correction value is used, the correction value of the unknown mobile terminal can be calculated by one measurement.

Further, the present invention can be used as a relative motion calculating means capable of continuously measuring the relative distance between two portable terminals and calculating a simple moving direction, relative speed and acceleration from a change in the distance therebetween. From the change in the relative distance, such relative motion calculating means can determine whether the mobile terminal of the other party is approaching or moving away, assuming that the mobile terminal of the user is stationary. In addition, the relative speed can be calculated from the temporal variation of the relative distance, and the acceleration can be calculated from the temporal variation of the relative speed.

The result of the measurement of the distance between the portable terminals is displayed on a display device so that the change with the passage of time can be recognized. In this method, a change in distance with respect to time is obtained by measuring the distance at regular time intervals. According to this measuring method, it can be used for monitoring a change in distance between two portable terminals. For example,
If the horizontal axis of the display is time and the vertical axis is distance, the progress of the distance with respect to the time can be seen.

[0055]

According to the first aspect of the present invention, a portable terminal capable of measuring a radio wave delay time in a transceiver mode of a PHS and calculating an accurate relative distance from a delay time with a small error based on an accurate reference time. Can be provided.

According to the second aspect of the present invention, there is provided a portable terminal capable of measuring a radio wave delay time in the transceiver mode of the PHS after determining measurement conditions and display conditions before measurement, and calculating a relative distance from the delay time. can do.

According to the third aspect of the present invention, it is possible to provide a portable terminal capable of measuring the delay time of a radio wave in the transceiver mode of the PHS and correcting the result of calculating the relative distance from the delay time.

According to the fourth aspect of the present invention, there is provided a portable terminal capable of measuring a delay time of a radio wave in a transceiver mode of a PHS and calculating a relative motion state with a partner portable terminal from a time variation of a relative distance calculated from the delay time. can do.

According to the fifth aspect of the present invention, it is possible to provide a portable terminal capable of measuring a radio wave delay time in a PHS transceiver mode, calculating a relative distance from the delay time, and displaying the result on a display as time elapses. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a portable terminal for describing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a frame of a portable terminal for describing an embodiment of the present invention.

FIG. 3 is a configuration diagram of a physical slot for control of a portable terminal for describing an embodiment of the present invention.

FIG. 4 is a configuration diagram of a physical slot for communication of a portable terminal for describing an embodiment of the present invention.

FIG. 5 is a configuration diagram showing a distance between a portable terminal A and a portable terminal B for describing an embodiment of the present invention.

FIG. 6 is a transmission / reception timing diagram when the distance between portable terminals is 0 for describing the embodiment of the present invention.

FIG. 7 is a timing chart of transmission and reception when the distance between portable terminals is D for describing the embodiment of the present invention.

[Explanation of symbols]

1 microphone, 2 signal synthesis circuit, 3 QPSK modulation circuit, 4 DA conversion circuit, 5 transmission circuit, 6 transmission / reception switching circuit, 7 antenna A, 8 reception circuit, 9 AD conversion circuit, 10 detection circuit, 11 receiver, 12 signal separation Circuit, 13 UW generation circuit, 14 UW detection circuit, 15
Counter, 16 signal processing control circuit, 17 operation unit,
18 storage unit, 19 display unit, 20 antenna B, 21
Clock section.

Claims (5)

[Claims] 1. Clock means for generating a reference time based on a standard time obtained by receiving a standard radio wave, and measuring means for measuring a delay time of a radio wave from another portable terminal based on the reference time And a time notifying unit that notifies the other portable terminal of a measurement start time to measure the delay time, and calculates a distance between the other portable terminal based on the measured delay time of the radio wave. A mobile terminal comprising a distance calculation unit. 2. The portable terminal according to claim 1, further comprising: a measurement condition notifying unit for notifying another portable terminal of a measurement condition and a measurement result display condition before measurement. 3. The portable terminal according to claim 1, further comprising a calibration unit for calibrating a measurement distance. 4. The mobile terminal according to claim 1, further comprising a relative motion calculating unit that can calculate the measured motion status of the other party. 5. The portable terminal according to claim 1, further comprising display means for displaying a measurement result on a display.