JP2001274761A - Tdma transmission timing setting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a TDMA transmission timing setting system by which the adjustment time for a slave unit, until it is ready for communication can be reduced by automatically and simply setting optimum transmission timing to the slave unit, without the need for the slave unit side to measure the distance between the slave unit and a base station. SOLUTION: The disclosed TDMA transmission timing setting system includes a test signal transmission means 9, that transmits a test signal from the slave unit(SU) to the base station (CS) according to preset transmission timing, a test response signal reception means 10 that receives a test response signal sent from the base station to the slave unit, in response to the test signal and discriminates whether received contents are normal, and a transmission timing adjustment means 8 that adjusts the preset transmission timing, when the means 10 discriminates that the received contents of the test response signal are not normal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TDMA (Time
More specifically, the present invention relates to a TDMA transmission timing setting method for optimally setting a transmission timing when transmitting a radio wave from a slave unit to a base station.

[0002]

2. Description of the Related Art In line connection of telephones, a base station and a telephone at a subscriber's house are conventionally individually connected by a subscriber line using a cable. In recent years, as a solution to various situations such as telephone congestion in developing countries, the so-called WLL (Wireless Lo
cal Loop) technology has been widely applied. Thus, a wireless communication system is configured.

FIG. 7 schematically shows the above-described WLL technology, in which a plurality of subscriber units 51A to 51C are provided with sub units 52A to 52C, respectively.
Are connected to a base station 54 by radio 53. Here, it is required that the distance between each of the slave units 52A to 52C and the base station 54 be as long as possible. Such a WLL
In technology, the TDMA scheme is often used in general.

In the WLL technology using such a TDMA system, an increase in transmission radio wave power increases a radio wave reach distance. On the other hand, a radio wave delay limits the distance.
This distance limit is caused by the property that radio waves from a slave unit near the base station reach the base station early, but radio waves from a slave unit far from the base station reach the base station with a delay. In other words, a distance difference occurs due to a time difference in radio wave arrival from a plurality of slaves to the base station.

In the WLL technology, TDD (Time
When the transmission time slot and the reception time slot are arranged on the time axis in the Division Duplex (time division multiplexing) method, the reception time slot arrives within a certain allowable time with respect to the transmission time slot in the base station. Is an essential condition. In general, a base station sets a detection time window indicating its allowable range on a time axis, and receives a radio wave arriving from a slave unit within that time. That is, the base station of the TDMA system provides a time slot reading time window for the received radio wave, and the radio wave from the slave unit that arrives within this time can be correctly detected, but the radio wave arrives outside the time window. The radio wave is configured not to be detected correctly.
Therefore, when transmitting a radio wave from the slave unit to the base station, the slave unit transmits a radio wave by setting an optimal transmission timing with respect to a time window in advance. Therefore, it is important for the slave unit to adjust the transmission timing to be optimal.

Here, if the timing is set so as to open the detection time window in accordance with the slave unit close to the base station, the timing of opening the detection time window is too early for the slave unit far from the base station. Then, the base station cannot receive radio waves from the slave unit correctly. Conversely, if the timing is set to open the detection time window in accordance with the distant handset, the timing of opening the detection time window will be delayed for the near handset. Cannot be received correctly.

Therefore, as described above, when the slave units are installed in the subscriber's house, conventionally, the distance between the base station and each slave unit is measured in advance, and each slave unit is determined based on this distance. Manually adjust the timing of the transmission of radio waves from the aircraft to the base station,
Adjustments are made so that the farther the slave unit is, the earlier the transmission timing is. For example, when using a landline telephone connected to a slave unit, the worker goes to a place where the slave unit is used, such as a house or a building, measures the distance between the base station and the slave unit on a map, and then manually Is set by adjusting the transmission timing of the slave unit. In the case where the slave unit is moved due to moving or the like, the construction worker goes to readjustment and sets the transmission timing in the same manner.

However, the above-described method of manually setting the transmission timing has a disadvantage in that the construction work must be carried out every time necessary, so that the adjustment work is unavoidably troublesome and troublesome. As a result, extra time is included in the adjustment time required for the communication of the slave unit. Therefore, when setting the transmission timing of the slave unit, the worker can easily measure the distance between the slave unit and the base station and automatically set the transmission timing without the need for a construction worker to visit each time. It is desired that a new method be used. In this case, it is premised that the slave unit accurately corrects the radio wave propagation delay time that changes according to the distance between the slave unit and the base station.

As described above, as an example of a distance measurement technique for measuring a radio wave delay time according to the distance between a slave unit and a base station at the slave unit side, for example, Japanese Unexamined Patent Publication No. Sho 59-183538 discloses a "synchronous system". Is disclosed. In this synchronization method, the ranging signal is transmitted from the slave to the base station, the base station transmits a return signal to the slave, and the slave calculates the delay time from the time difference between the transmitted radio wave and the received radio wave. And a method in which the base station compares the time slot received from the slave with the reference position, and notifies the slave of the deviation information, so that the delay time due to the distance between the base station and the slave is measured. I have to.

[0010] As another example of the radio wave delay time measuring technique according to the distance, for example, Japanese Patent Application Laid-Open No. Sho 62-67939 discloses the "TDMA acquisition method".
The TDMA acquisition system transmits a burst signal called an acquisition signal from a slave unit to a base station, and the base station receives the burst signal and notifies the slave unit of information of deviation from a predicted position. The radio wave delay time according to the distance from the slave unit is measured.

[0011] As another example of the radio wave delay time measuring technique according to the distance, for example, Japanese Patent No. 2962277 discloses a "TDMA transmission timing setting method". In the TDMA transmission timing setting method, a test signal including a specific bit pattern is transmitted from a slave to a base station, and the base station returns the test signal to the slave as it is,
By collating the bit pattern received by the slave with the transmitted bit pattern, the radio wave delay time according to the distance between the base station and the slave is measured based on the result of the comparison.

[0012]

However, each of the above-described conventional techniques for measuring a radio wave delay time according to distance has the following problems. First, in the "synchronous method" described in JP-A-59-183538 and the "TDMA acquisition method" described in JP-A-62-67939, the time difference between a transmitted radio wave and a received radio wave is both described. Is common in that the distance is measured based on the base station, but in these systems it is assumed that the base station receives the ranging signal or the acquisition signal transmitted from the slave unit, so this assumption is broken. In such a case, there is a first problem that distance measurement becomes impossible. The reason is that the above-described ranging signal or acquisition signal is transmitted to the base station before the transmission timing is optimally set, and particularly in the case of long distance, the base station is assumed to arrive. Since the signal arrives at the base station later than the detection time window, which is a time, the base station fails to receive the signal and the base station cannot notify the slave unit of the deviation information. Therefore, it is desired to optimally set the transmission timing so that the ranging signal or the acquisition signal reaches the base station within the detection time window.

The above-mentioned "synchronous system" and "TDMA"
In the "acquisition method", there is a second problem that time measurement in the slave unit is inaccurate. The reason is that
The measurement time includes a processing delay from reception of a radio wave to transmission at the base station.

The above-mentioned "synchronous system" and "TDMA"
The “acquisition method” has a third problem that the configuration of the base station device becomes complicated. The reason is that
The base station needs a means for measuring the deviation from the reference time slot and a means for notifying the slave unit of the measurement result as information.

[0015] Next, in the "TDMA transmission timing setting method" described in Japanese Patent No. 2962277, there is no problem even if the base station cannot normally receive the test signal as long as the test signal is returned to the slave unit. However, in the case of a long distance, there is a problem that the base station cannot detect the arrival of the test signal, so that the distance cannot be measured. The reason is that the base station cannot detect the arrival of the test signal and cannot return the test signal from the base station to the slave unit.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and automatically and simply sets an optimal transmission timing without measuring the distance between a slave unit and a base station on the slave unit side. Accordingly, it is an object of the present invention to provide a TDMA transmission timing setting method capable of shortening an adjustment time until a slave unit can communicate. Further, the present invention provides a TDM system in which the optimum transmission timing can be finally set even if the base station cannot receive the radio wave from the slave unit in a state where the transmission timing is insufficiently adjusted.
It is intended to provide an A transmission timing setting method.

[0017]

In order to solve the above-mentioned problems, the invention according to claim 1 relates to a TDMA transmission timing setting method for setting a transmission timing of a slave unit in a time division multiple access system of a wireless communication system. And the test signal to T
First means for transmitting a test frame on a DMA frame from a slave to a base station in accordance with a preset transmission timing, and a test transmitted from the base station to the slave based on the test frame Second means for receiving a response frame, and determining the received content of the test response frame. If the determination result is not normal, the transmission timing of the test frame transmitted from the slave unit is optimized. And a third means for adjusting.

The invention according to claim 2 relates to a TDMA transmission timing setting method for setting a transmission timing of a slave unit in a time division multiple access system of a wireless communication system, wherein a test signal is preset from the slave unit to a base station. Test signal transmitting means for transmitting in accordance with the transmission timing, a test response signal for receiving a test response signal transmitted from the base station to the slave unit based on the test signal, and determining whether or not the received content is normal It is characterized by including receiving means and transmission timing adjusting means for adjusting the transmission timing when it is determined that the received content of the test response signal is not normal.

According to the third aspect of the present invention, the T
According to the DMA transmission timing setting method, the test signal transmitting means includes a test signal generating circuit for generating a test signal, a frame assembling circuit for assembling a test frame with the test signal as an input, and outputting based on the transmission timing. And a modulating circuit for modulating the output of the frame assembling circuit and transmitting the modulated signal from the transmitting / receiving antenna to the base station.

According to a fourth aspect of the present invention, there is provided the TDMA transmission timing setting method according to the second or third aspect, wherein the test response signal receiving means demodulates an input received from the transmitting / receiving antenna. A frame detection circuit for restoring a test frame from the output of the demodulation circuit, and a result determination circuit for determining whether or not the test frame is normal based on the contents of the test frame.

According to a fifth aspect of the present invention, there is provided the TDMA transmission timing setting method according to the second, third or fourth aspect, wherein the transmission timing adjusting means adjusts the transmission timing based on an output of the result determination circuit. It is characterized by comprising a transmission timing adjusting circuit for generating a control signal.

The invention according to claim 6 is the invention according to claim 5,
According to the DMA transmission timing setting method, in the slave unit, a timing at which a reception frame and a transmission frame are separated by a half of a TDMA frame length is set in advance as a reference transmission timing, and the transmission timing adjustment circuit sets The transmission timing is controlled to be shorter than the reference transmission timing as the distance between the base station and the base station increases.

According to a seventh aspect of the present invention, there is provided the TDMA transmission timing setting method according to the fourth, fifth or sixth aspect, wherein when the result determination circuit determines that the test frame is normal, the transmission timing is determined. The transmission is fixed at a transmission timing set in advance by an adjustment circuit.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. The description will be specifically made using an embodiment. FIG. 1 shows an embodiment of the present invention, T
FIG. 2 is a block diagram illustrating a configuration of a slave unit used in a DMA transmission timing setting method. The slave unit used in the TDMA transmission timing setting method of this example is, as shown in FIG.
A test signal generating circuit 1 for generating a test signal, a frame assembling circuit 2 for assembling a test frame (TDMA frame) with the test signal as an input, and outputting the test frame based on a preset transmission timing, and an output of the frame assembling circuit 2 A modulation circuit 3 for modulating the signal and transmitting a test frame from the transmission / reception antenna 4 to the base station;
A demodulation circuit 5 for demodulating an input received from the transmission / reception antenna 4, a frame detection circuit 6 for restoring a test frame from an output of the demodulation circuit 5, and whether the test frame is normal based on the contents of the test frame. And a transmission timing T based on the output of the result determination circuit 7.
and a transmission timing adjustment circuit 8 for generating a control signal for adjusting d.

Here, the test signal generating circuit 1, the frame assembling circuit 2, and the modulating circuit 3 constitute test signal transmitting means 9. Also, a demodulation circuit 5, a frame detection circuit 6
The result determination circuit 7 constitutes the test response signal receiving means 10. Further, the transmission timing adjusting circuit 8 itself constitutes a transmission timing adjusting means.

The test signal generated from the test signal generating circuit 1 includes, for example, a sequence number different for each test signal as an identifier. Alternatively, a time stamp may be used as the identifier. If the time interval between the test signals is sufficiently wide, the identifier is not necessary because the test response frame, which is a test response signal from the base station, and the test frame, which is a test signal from the slave unit, can be easily associated. .
The frame assembling circuit 2 receives the test signal,
Elements necessary for establishing a wireless link such as CRC (redundancy cyclic check bit) are added to assemble a test frame (TDMA frame). Next, the test frame is delayed from the frame reception time by the time of the transmission timing Td according to the control signal from the transmission timing adjusting means 8, and then sent to the modulation circuit 3 for modulation.
The test frame is transmitted from the transmission / reception antenna 4 to a base station (not shown) as a test signal.

When the base station receives the test frame, which is a test signal from the slave unit, it creates a test response frame as a test response signal and notifies the slave unit of the detection result. If the interval between the test signals is sufficiently wide and the correspondence with the test response signal can be easily taken as the notification content, it is sufficient to notify the information as to whether or not the synchronization pull-in has succeeded.

In the slave unit, a test response frame, which is a test response signal from the base station, is received by the transmission / reception antenna 4. The demodulation circuit 5 receives and demodulates the test response frame, guides it to the frame detection circuit 6, detects synchronization, restores the frame as a test response frame, and performs processing such as a CRC check as necessary. The result determination circuit 7 determines the reception result at the base station described in the test response frame. When the result of the determination is normal, the result determination circuit 7 determines that the transmission timing at that time is optimal, and sets the transmission timing Td held by the transmission timing adjustment circuit 8 at that time as an optimal adjustment value. Save (fixed)
Thereafter, transmission is performed at the transmission timing Td based on the fixed adjustment value.

If the result of the determination is not normal, the result determination circuit 6 determines that the preset transmission timing is inappropriate, and issues an instruction to the transmission timing adjustment circuit 8 to adjust the transmission timing. . This instruction is performed, for example, in such a manner that the transmission timing is advanced by a time corresponding to 1 bit. The transmission timing adjusting circuit 8 outputs a control signal indicating a new transmission timing Td to the frame assembling circuit 2 based on the instruction. As a result,
The test frame is transmitted from the slave unit to the base station based on the new transmission timing that has been reset so that the arrival is advanced by 1 bit equivalent time △ compared to the previous transmission timing. Thereafter, the same result determination is performed, and the test timing, which is the test signal resulting from adjusting the transmission timing, is normally received by the base station, and the transmission timing is continuously adjusted until the slave confirms it. .

Next, referring to FIG. 2, the TDMA of this example will be described.
The timing relationship between the base station and the slave unit in the transmission timing setting method will be described. As is clear from the figure, as an example, the transmission time slot of the base station (CS) is T1,
The receiving time slots of the base station are indicated by T2, T3 and T4, and R1, R2, R3 and R4, each time slot including one frame. Then, these four transmission time slots T1, T2, T3 and T4, and 4
An example is shown in which a TDMA frame is composed of eight reception time slots R1, R2, R3, and R4, for a total of eight time slots. TDMA frame length is Tf
Is set to Here, in the base station, the reception frame and the transmission frame are 1/1 / TDMA frame length Tf.
It is assumed that the timing separated by two is optimal and is set in advance to the reference transmission timing.

In the base station, for a certain slave unit (SU),
The transmission time slot and the reception time slot are fixedly used. For example, numbers corresponding to T1 and R1 are assigned. In the base station, when the time difference between T1 and R1 is exactly Tf / 2, the optimum timing is reached. When the slave unit is far away from the base station, the radio wave delay τ increases. As a result, the timing of R1 transmitted from the slave unit and reaching the base station is delayed. If the delay exceeds an allowable range (detection time window), normal reception cannot be performed at the base station.

FIG. 2 shows a case where the base station transmits a frame to the slave unit using the time slot T1. This frame arrives at the slave unit from the base station after a radio wave delay τ. Based on the reception timing, the slave unit inserts a transmission frame into the time slot R1 after the adjusted transmission timing Td and transmits it to the base station. Since this frame generally passes through the same propagation path, the same radio wave delay τ
Later, it reaches the base station. Thus, half-duplex communication is performed. The radio wave delay τ may be different in both directions.

Next, referring to FIG. 3, the TDMA of this example will be described.
A transmission timing adjustment method in the transmission timing setting method will be described. This figure shows a case where the transmission timing is improper immediately after the power of the slave unit is turned on. The slave unit receives a notification radio wave from the base station (not shown), and transmits a test signal as a test frame by putting the test signal on the frame F1 at a timing separated by Tf / 2. Therefore, the cycle T of the test signal is N · Tf (N is an integer). The time at which the test signal in frame F1 arrives at the base station (time 0) is too late, so that the base station cannot detect it, does not notice the arrival of the test signal, and does not transmit the test response signal to the slave unit. In the slave unit, since the test response signal does not arrive even after the predetermined time has elapsed, the slave unit is determined to be NG (defective). If the transmission timing from the slave unit is not appropriate, a bit error may occur in the test signal received by the base station. In this case, the base station transmits a test response signal indicating that there is a bit error.

In any case, if the slave unit cannot receive the test response signal, or if it is able to receive the test response signal, it is determined that there is an abnormality in the content, the transmission interval of the test signal is set to T To T− △, and the next test signal is transmitted on the frame F2 earlier than the previous test signal. In this case, the time at which the test signal arrives at the base station is advanced by △ from the previous time. However, as apparent from FIG. 3, the test signal cannot be detected because it does not yet fall within the detection time window (time T is slightly past). Therefore, the base station notifies the slave unit of the result.

Next, when the interval from the previously transmitted test signal by the slave unit is set to T- △ again, and the next test signal is transmitted in the frame F3, the test signal arrives at the base station earlier by △. As is clear from FIG. 3, the base station cannot be detected again (only a little after time 2T) because it only covers the rear part of the detection time window and the first half is lost. The slave unit receives this result, and sets the interval from the previously transmitted test signal to T- △, and transmits the next test signal in frame F4. This test signal is
As soon as it reaches the base station, it is normally received as shown in FIG. 3 (time 3T). Therefore, the base station notifies the slave unit that it is normal.

Thereafter, the slave sets the transmission interval of the test signal to TD.
The value is returned to T, which is an integral multiple of the MA frame length Tf. further,
As a precautionary measure, the next test signal can be transmitted in the frame F5. In this case, the base station returns the frame F after a time T from the reception time of the test signal of the previous frame F4.
Since the test signal of No. 5 arrives, this is also normally received. It is not always necessary to transmit a new test signal to be placed on the frame F5 because it is a reconfirmation just in case. As described above, by automatically adjusting the transmission timing by the slave based on the response from the base station, the optimum transmission timing can be obtained as a result.

Here, in the method of adjusting the transmission timing, at the time of the first startup, a short distance is assumed, and the transmission timing Td = Tf / 2 is set as described above. Except for a very short distance, the determination result is NG. Therefore, it is determined that the distance is not very short, and Td is shortened by Td = Tf / 2− ／. In the case of NG, the result is further shortened by Td = Tf / 2-2 △, which is further reduced by △, that is, a total of 2 △. If the operation of shortening each time by △ is continued, the time when the test signal arrives at the base station becomes the reference time (time n · T) (n = 0, 1, 2, 2, 3).
(3, ...) will be advanced by $ each time. Therefore, the test signal always arrives at the reference time sometime.

Referring to FIG. 2, finally, Td = Tf
/ 2-2τ corresponds to this. At this point in time when the base station succeeds in receiving, the transmission timing Td is fixed at that value. Thus, the adjustment of the optimal transmission timing can be performed by a simple operation. Furthermore, if there is a margin in the transmission timing, the transmission timing is advanced by Δ even after successful reception at the base station, and is continued until the transmission result becomes NG again because the reception result is too early. At this time, if the successful transmission timings are, for example, three, the minimum and maximum are discarded from these three transmission timings, and if the central transmission timing is selected, the margin for the fluctuation of the radio wave transmission path can be obtained. , So that a flexible operation can be performed. Here, the number 3 in the example has no special meaning, and there is no change in selecting a value near the safe center regardless of the number.

Next, a method of adjusting the transmission timing will be described in more detail with reference to the frame timing chart of FIG. When the slave unit starts up by turning on the power, it monitors the radio wave from the base station and detects the notification signal (here,
The base station constantly emits an annunciation signal radio wave for notifying the existence of the base station and the base station ID to an unspecified number of slave units. However, the notification signal does not include time information). Based on the reception time, the first test signal is transmitted in the frame F1 at the timing Tf / 2 is transmitted to the base station. Since the initial value of the transmission timing Td is set to a very short distance, the base station cannot detect this test signal. This is because the base station arrives later than the detection time window in which the base station is waiting. Therefore, since the base station cannot capture all the bits of the test signal of frame F1, it does not transmit the test response signal. From the viewpoint of the slave unit, if it is determined that the test response signal corresponding to the test signal of the frame F1 does not arrive within a predetermined time, it is determined that the reception at the base station has failed.

Thereafter, the transmission timing is advanced and the next test signal is transmitted in the frame F2. Thereafter, similarly, the test response signal does not reach the slave unit due to reception failure at the base station. The base station will drop the last bit out of the time window for the frame F3 carrying the next test signal. Since the base station performs synchronization, the radio wave input during the time when the detection time window is open is restored as a frame, so that the restored frame does not have the (actually) signal frame at the beginning. The bits become indeterminate, followed by a test frame. However, the frame portion after the length (number of bits) specified as the frame length is truncated and discarded. Based on the restored frame, a position where a synchronization pattern is supposed to exist is searched in advance. However, the synchronization pattern cannot be detected because the received frame is delayed. This is because the synchronization pattern does not fall within the search range, and a part of the synchronization pattern exists behind the detection range. This occurs because the synchronous search range is generally shorter than the frame length. The reason for restricting the length to a short value is to prevent accidental synchronization (pseudo-synchronization) by retrieving information bit portions other than the synchronization pattern by chance that data coincident with the synchronization pattern may be present. Therefore, the base station fails in synchronization detection and cannot read the contents of the test signal of frame F3 and discards it. Furthermore, since the slave unit ID (identifier) cannot be detected, a test response signal cannot be returned to the slave unit.

Next, when a test signal carried on the frame F4 is transmitted, as shown in FIG. 3, this test signal is normally received by the base station, so that synchronization detection succeeds,
The base station can read the contents of the test signal of the frame F4. The base station checks the channel type of the received frame, knows that this frame is a test frame, and transmits a test response signal to the slave unit. Upon receiving the test response signal, the slave unit restores the frame to a frame and sends it to the result determination circuit 7. The result determination circuit 7 examines the information field in which the test result in the frame is described, and detects that its own slave unit ID is written. At the same time,
The sequence number of the test signal is also known, and at what transmission timing the transmitted frame is normally received.
That is, it is possible to know that the transmission timing at that time was optimal. Subsequent frame transmission is performed with this optimal transmission timing fixed. Since the subsequent communication is also performed at the optimum transmission timing, it is guaranteed that the base station can receive the communication normally.

FIG. 5 is an example of a frame configuration diagram used in the TDMA transmission timing setting method of this example. FIG. 5A is a frame configuration diagram showing a test frame transmitted from the slave unit to the base station, and FIG. 5B is a frame configuration diagram showing a test response frame transmitted from the base station to the slave unit. Each of the test frame and the test response frame is included in one time slot. Therefore, in this case, the test signal and the test frame are synonymous. The test response signal and the test response frame are also synonymous. The test frame includes, in order from the beginning, a lamp 11, a start symbol 12, a preamble 13, a synchronization pattern 14, a channel type 15, a base station ID (identifier) 16, and a slave unit ID.
17, an identifier (sequence number or the like) 18 and a CRC 19 are included, and the identifier (sequence number or the like) 18 forms an information field 20.

Similarly, the test response frame includes a ramp 21, a start symbol 22, a preamble 23, a synchronization pattern 24, a channel type 25,
A base station ID (identifier) 26, a slave unit ID 27, an identifier (sequence number) 28, and a CRC 29 are included.
27 and an identifier (sequence number) 28 constitute an information field 30. The test frame and the test response frame are the same except for the configuration of the information fields 20 and 30.

The test signal generating circuit 1 includes an information field 2
0 is written in the frame identifier 18 for frame identification, and the result determination circuit 7 analyzes the information field 30 of the test response frame,
Is determined. The frame identifier 28 may be a frame sequence number for identifying when the frame was transmitted or a time stamp indicating the transmission time. In the channel type 15 in the frame, it is described that this frame is a test signal.

The base station returns the result of receiving the test frame described in the information field 30. If the base station succeeds in establishing the synchronization and succeeds in the reception, the contents of the identifier 18 such as the slave unit ID 17 and the frame sequence number can be read, and this result is stored in the information field 30 of the test response frame. At the same time, the identifier 28 is written and transmitted from the base station to the slave unit. The base station
If the detection of the synchronization pattern fails, the reading of the slave unit ID 17 fails, or the error is detected in the CRC 19, and the test frame cannot be normally received, the cause of the failure is written in the information field 30. Return it or
Or do not know the reception and do not return. Handset ID1
In the case of reading failure of No. 7, nothing is written in the handset ID field 27 or an incorrect ID is written.

The slave determines the contents of the information field 30 of the received test response frame and determines its own slave ID 27.
Is described, the transmitted identifier 28 is copied in the information field 30, and if there is no other description indicating abnormality, it is determined that the test signal has been correctly received.
By checking the identifier 28, it is possible to know at which transmission timing the corresponding test frame was transmitted. Therefore, it is possible to know that the transmission timing set at that time was a reception timing at which the base station can receive.

As described above, according to this example, the transmission timing is automatically adjusted by the slave based on the response from the base station, so that the optimum transmission timing can be obtained. When installing in a house, for example, when a landline telephone is connected to a slave unit and used, as in the past, a construction worker goes to a place where the slave unit is used, such as a house or a building, and a base It is possible to eliminate the trouble and trouble of measuring the distance between the station and the slave unit and manually setting the transmission timing of the slave unit. Further, even when the slave unit is moved due to moving or the like, the transmission timing is automatically set according to the new distance, so that the construction worker does not need to go to readjustment.

FIG. 6 is a diagram schematically showing a configuration of a network system to which the TDMA transmission timing setting method of this example is applied. As shown in the figure, the network system comprises a base station (CS) connected to a network 31 and a slave unit (SU) each having a transmitting / receiving antenna 3.
The terminals 3 and 34 are wirelessly connected by the TDMA method, and a terminal 35 such as a telephone is further connected to the slave unit (SU). In the slave unit (SU), functions necessary for communicating with the terminal 35 are mounted in addition to the test signal transmission / reception function shown in FIG. In the case where the terminal 35 is a fixed telephone or a fixed FAX (facsimile) fixedly installed indoors or in a building, the slave unit does not need to move, so the transmission timing is set once when the slave unit is turned on. Just do it.

As described above, according to the TDMA transmission timing setting method of this example, a test signal generating circuit 1 for generating a test signal and a test frame with the test signal as an input are assembled to meet a predetermined transmission timing. The test signal transmitting means 9 is composed of a frame assembling circuit 2 for outputting a signal based on the output from the frame assembling circuit 2 and a modulation circuit 3 for modulating the output of the frame assembling circuit 2 and transmitting the modulated signal to the base station from the transmitting / receiving antenna 4. A demodulation circuit 5 for demodulating the received input; a frame detection circuit 6 for restoring a test frame from the output of the demodulation circuit 5; and a result determination circuit for determining whether or not the test frame is normal based on the contents of the test frame 7 constitute a test response signal receiving means 10, and further generate a control signal for adjusting the transmission timing based on the output of the result determination circuit 7. Since it is configured to transmit timing adjustment means by the transmission timing adjusting circuit 8 may set the transmission timing without complicating the structure of the apparatus of the base station. Therefore, even if the distance between the slave unit and the base station is not measured on the slave unit side, by automatically and simply setting the optimum transmission timing, the adjustment time until the slave unit can communicate can be reduced. In addition, the base station automatically adjusts to the optimal transmission timing even if it cannot receive the radio wave from the slave unit under the condition that the transmission timing is insufficiently adjusted. Can be received.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and the design may be changed without departing from the scope of the present invention. Is also included in the present invention. For example, in the embodiment, an example in which a TDMA frame is composed of four transmission time slots T1, T2, T3, and T4 and four reception time slots R1, R2, R3, and R4, for a total of eight time slots. However, this is merely an example, and can be arbitrarily changed according to the purpose, application, and the like.

[0051]

As described above, the TDM of the present invention is
According to the A transmission timing setting method, a test signal transmitting means for transmitting a test signal from a slave to a base station in accordance with a preset transmission timing, and a test response transmitted from the base station to the slave based on the test signal. A test response signal receiving means for receiving a signal and determining whether or not the received content is normal; and a transmission timing adjustment for adjusting a preset transmission timing when it is determined that the received content of the test response signal is not normal. The transmission timing can be set without complicating the configuration of the base station apparatus. Therefore, even if the distance between the slave unit and the base station is not measured on the slave unit side, by automatically and simply setting the optimum transmission timing, the adjustment time until the slave unit can communicate can be reduced. In addition, the base station automatically adjusts to the optimal transmission timing even if it cannot receive the radio wave from the slave unit under the condition that the transmission timing is insufficiently adjusted. Can be received.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a slave unit used in a TDMA transmission timing setting method according to an embodiment of the present invention.

FIG. 2 shows the TDMA transmission timing setting method.
FIG. 4 is a diagram illustrating a timing relationship between a base station and a slave unit.

FIG. 3 illustrates the TDMA transmission timing setting method.
FIG. 4 is a diagram illustrating a method of adjusting transmission timing.

FIG. 4 shows the TDMA transmission timing setting method.
FIG. 4 is a diagram illustrating a method of adjusting transmission timing.

FIG. 5 is a diagram illustrating a frame configuration used in the TDMA transmission timing setting method.

FIG. 6 is a diagram schematically showing a configuration of a network system to which the TDMA transmission timing setting method is applied.

FIG. 7 is a diagram schematically illustrating a WLL technology in a conventional wireless communication system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Test signal generation circuit 2 Frame assembly circuit 3 Modulation circuit 4, 33, 34 Transmit / receive antenna 5 Demodulation circuit 6 Frame detection circuit 7 Result determination circuit 8 Transmission timing adjustment circuit 9 Test signal transmission means 10 Test response signal reception means 11, 21 Lamp 12, 22 Symbol 13, 23 Preamble 14, 24 Synchronization pattern 15, 25 Channel type 16, 26 Base station ID (identifier) 17, 27 Remote unit ID 18, 28 Identifier (sequence number) 19, 29 CRC 20, 30 Information Field 31 Network 35 Terminal CS Base station SU Slave unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04L 29/08 H04L 13/00 307Z F-term (Reference) 5K028 AA11 BB04 BB06 CC02 DD01 DD02 HH02 HH03 KK01 KK03 NN43 PP02 PP15 PP23 5K033 AA02 CB15 DA01 DA19 DB11 5K034 AA03 DD01 EE03 EE13 HH01 HH02 HH10 HH11 MM03 NN12 NN22 QQ08 RR01 TT02 5K047 AA02 BB01 BB05 CC06 HH17 JJ08 KK03 KK15 5K067 CC04 KK15 5K067 CC

Claims (7)

[Claims] 1. A TDMA transmission timing setting method for setting a transmission timing of a slave unit in a time division multiple access system of a wireless communication system, wherein a test signal is carried on a TDMA frame to form a test frame and a predetermined transmission is performed. First means for transmitting from the slave to the base station according to timing; second means for receiving a test response frame transmitted from the base station to the slave based on the test frame; and the test response frame. And a third means for adjusting the transmission timing of the test frame transmitted from the slave unit to be optimum if the determination result is not normal. Transmission timing setting method. 2. A TDMA transmission timing setting method for setting a transmission timing of a slave unit in a time division multiple access system of a wireless communication system, wherein a test signal is transmitted from the slave unit to a base station in accordance with a preset transmission timing. Test signal transmitting means for transmitting; a test response signal receiving means for receiving a test response signal transmitted from the base station to the slave unit based on the test signal, and determining whether or not received content is normal; A transmission timing adjusting means for adjusting the transmission timing when it is determined that the received content of the test response signal is not normal. 3. The test signal transmitting means for generating a test signal, a test signal generating circuit, a frame assembling circuit for assembling a test frame with the test signal as an input, and outputting the test frame based on the transmission timing; 3. The TDMA transmission timing setting method according to claim 2, further comprising a modulation circuit that modulates an output of the assembling circuit and transmits the modulated signal to the base station from the transmission / reception antenna. 4. A demodulation circuit for demodulating an input received from the transmission / reception antenna, a frame detection circuit for restoring a test frame from an output of the demodulation circuit, 4. The TDMA transmission timing setting method according to claim 2, further comprising a result determination circuit that determines whether the test frame is normal based on the content. 5. The transmission timing adjusting circuit according to claim 2, wherein the transmission timing adjusting means comprises a transmission timing adjusting circuit for generating a control signal for adjusting the transmission timing based on an output of the result determination circuit. The described TDMA transmission timing setting method. 6. In the slave unit, a timing at which a reception frame and a transmission frame are separated by a half of a TDMA frame length is set in advance as a reference transmission timing,
6. The TDMA transmission timing according to claim 5, wherein the transmission timing adjustment circuit controls the transmission timing to be shorter than the reference transmission timing as the distance between the slave unit and the base station increases. Setting method. 7. The transmission timing adjustment circuit, wherein when the result determination circuit determines that the test frame is normal, the transmission timing is fixed to a transmission timing set in advance by the transmission timing adjustment circuit. 4. The TDMA transmission timing setting method according to 4, 5, or 6.