JP2003061152A - Transmitter-receiver, transmission system, and propagation delay control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter-receiver that can normally transmit/receive data even when a communication opposite station adopting the TDMA system is located at a distance in excess of a propagation delay guard time and to provide a communication system and a propagation delay control method. SOLUTION: The communication system is provided with calculation sections 4, 5, and 7 that calculate a propagation delay time of a received signal and gives a propagation delay excess detection command denoting it when the propagation delay time calculated by the calculation sections is more than the propagation delay guard time, and a control section 8 that quickens a transmission timing of transmission data when receiving the a propagation delay excess detection command denoting that the propagation delay time calculated by the calculation sections is more than the propagation delay guard time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter / receiver, a communication system and a propagation delay control method, and more particularly to time division multiple access (TDMA).
TECHNICAL FIELD The present invention relates to a technique for allowing a subscriber station in which a delay time exceeding a propagation delay guard time has occurred normally to receive data in a standard wireless communication network.

[0002]

2. Description of the Related Art Conventionally, in the field of mobile communication, a technique called multiple access has been used in which a plurality of users share a wireless transmission path and communicate at the same time. As one of such multiple access, a TDMA method that separates wireless channels according to time is known.

A mobile communication system adopting the TDMA system is usually composed of a plurality of base stations fixedly installed and a plurality of mobile stations moving within a service area covered by each base station. There is. By the way, the base station in the communication system described in this specification is itself movable. Therefore, in order to distinguish it from the “base station” and the “mobile station” in a normal communication system, they are called “reference station” and “subscriber station”, respectively.

The operation of this conventional mobile communication system will be described with reference to the timing chart shown in FIG. The reference station periodically transmits a reference frame (TS0) as shown in FIG. 4 (B). When each subscriber station is the receiving station, each subscriber station generates reception timing in synchronization with the received reference frame, and the data sent from the reference station or another subscriber station in the reception time slot assigned to itself. To receive. On the other hand, when the own station is the transmitting station, the TDMA frame is generated in synchronization with the received reference frame,
Data is transmitted in the transmission time slot assigned to the own station.

In such transmission / reception, FIG.
Also, as shown in FIG. 4D, the timing of transmission and reception for the subscriber station located away from the reference station is delayed by the propagation time. Therefore, in the TDMA method, the propagation delay guard time G is specified as shown in FIG. 5 in order to allow the received data to fit within the frame even if a delay occurs. Due to this propagation delay guard time G, received data D1 shown in FIG.
Even if is shifted to the right in FIG. 5, the received data can be normally received within the frame. By defining this propagation delay guard time, the allowable propagation delay time within the frame is determined. As a result, the maximum separation distance from the reference station to the subscriber station is determined, and the operation area of the TDMA network is defined.

As a related technique, Japanese Patent Laid-Open No. 2000-26
Japanese Patent No. 1371 discloses a "transmission / reception device". In this transmission / reception device, the determination unit extracts and counts a retransmission request from the received signals after the CRC check, which is the output of the CRC check unit, and determines whether the number of consecutive retransmission requests received reaches an arbitrary threshold value. It is determined whether or not, and if it is reached, the timing control unit is instructed to switch the transmission timing. The timing control unit advances the transmission timing based on the instruction from the determination unit, and sets a new transmission timing in the modulation unit and the transmission RF unit. This makes it possible to suppress the propagation delay exceeding the guard time length.

Further, Japanese Patent Laid-Open No. 2000-269882 discloses "a delay correction system in a radio telephone system". In the delay correction system in this radio telephone system, a base station device and at least one subscriber device perform transmission / reception operations via communication means provided in the base station device according to the TDMA method with the synchronization reference. . This delay correction system includes a measurement instruction input means for inputting a delay measurement instruction for performing delay measurement, and a delay for measuring a delay amount between a base station device and a subscriber device in response to the input of the delay measurement instruction. And a first timing adjusting unit which is provided in the subscriber device, receives the transmission information to be sent to the base station device in the assigned time slot, adjusts the timing according to the delay amount, and sends the adjusted information. There is. With this configuration, it is possible to automatically correct the transmission delay between the subscriber device and the base station device in the wireless telephone system.

Further, Japanese Patent Laid-Open No. 63-292838 discloses "propagation delay adjustment method". In this propagation delay adjustment method, a card bit is provided in the burst transmission signal to adjust the inter-station propagation delay required in the wireless TDMA method, so that the adjustment within the bit is unnecessary, and the dedicated time slot is used for continuous operation. It enables automatic adjustment.

Further, Japanese Patent Laid-Open No. 4-207244 discloses
The "demodulation method" is disclosed. In this demodulation method, a plurality of stations are transmitted from other stations in a demodulation method using quasi-coherent detection, which is used in a communication system in which a modulation transmission path of the same frequency band is divided and shared in time series. The station receiving the burst modulation signal has means for acquiring sampling timing in bit synchronization with the burst signal prior to receiving the burst signal, and the station of the quasi-synchronous detector based on the sampling timing. The vector signal on the phase plane which is the output is sampled and stored in the memory, the phase rotation amount of the vector signal is estimated based on the layers of the plurality of vector signals stored in the memory, and based on the estimated phase rotation amount. The phase of the vector signal is corrected and the received signal is determined.

Further, Japanese Patent Laid-Open No. 11-88394 discloses that
"Optical transmitter / receiver control device in optical PDS system" is disclosed. The optical transmission / reception unit control device in this optical PDS system includes a synchronization detecting unit that receives upstream data from the slave station device and detects a frame synchronization pulse in the master station device 1, and a delay time that measures the delay time at the timing. Measurement part, delay time memory part for holding delay time, delay time transfer part for transferring delay data to slave station side, comparison of delay time of 0 system and 1 system, and comparison for controlling transmission / reception timing It has a processing unit, a downlink delay control unit that controls the transmission timing of the downlink signal, and an uplink delay control unit that controls the reception timing of the uplink signal. With this configuration, the master station device and the plurality of slave station devices are connected by the TCM transmission method and
In an optical PDS system connected by using the DMA control method, even if the distance intervals of the optical transmission lines forming the redundant system are not equal, the transmission delay time difference of the optical transmission lines is absorbed, and the instantaneous non-interruptive forced switching is performed. realizable.

Further, Japanese Patent No. 2518208 discloses a "mobile communication system". According to this mobile communication system,
When the base station receives the transmission signal from the mobile station, the base station detects the deviation amount from the reference value of the reception timing and adjusts the transmission timing of the mobile station based on it.
In the base station, the time width of the guard time, which should be set in consideration of the propagation delay time of the mobile station transmission signal as the reception time slot, can be greatly reduced as compared with the conventional case, and therefore the information transmission efficiency can be improved.

Further, Japanese Patent No. 2861955 discloses an "inter-station phase synchronization system". This inter-station phase synchronization system is composed of a master station and a plurality of slave stations, transmits a frame signal from the master station to the plurality of slave stations, and performs phase synchronization of these frames between the slave stations. In the inter-station phase synchronization system for, the master station, a delay amount detecting means for detecting a delay amount with respect to a specified timing position of the reception timing position of the timing signal transmitted from the slave station for phase synchronization, The slave station transmits the delay information according to the delay amount to the slave station at a cycle n times the cycle of the frame signal (n is an integer of 2 or more), and the slave station transmits the timing signal. Transmission means for transmitting to the master station, extraction means for extracting the delay information included in the transmission signal from the master station, and transmission from the master station for a delay time of half the delay amount indicated by the extracted delay information Frame signal And a delay means for delivering while allowed extending to service areas.

Further, Japanese Patent No. 3031292 describes "optical PD
The transmission delay difference absorption method in the S system is disclosed. In the transmission delay difference absorption method in this optical PDS system, a master station device and a plurality of slave station devices are connected to a TCM (Time Compr.
Ession Multiplex) transmission method and TDMA (Time Divis)
I / O PDS having a redundant configuration of 0 system / 1 system and 2 systems in the section from the master station device to the star coupler, which is connected by bidirectional optical one-core transmission using a control system.
In the (Passive Double Star) system, the slave station device is an optical transmitter / receiver that receives the downlink data from the master station device for phase adjustment on the receiving side and detects a frame synchronization pulse and a synchronization detector. By receiving the reception data of the 1-system next to the 0-system and the synchronization counter that counts in synchronization, the output timing of the 0-system synchronization timing and the reception timing of the 1-system are compared to determine the 0-system The delay data measured by the delay time measuring unit of the master station device is inserted into the downlink data by comparing the receiving side timing of the 1-system and the synchronization timing, and the downlink data is received by the optical transmitting / receiving unit of the slave station device. A delay data detection unit for receiving delay data and extracting delay data for delay adjustment on the transmission side, a memory unit for holding 0-system delay data, and a memory unit for holding 1-system delay data. , A system selection signal detection unit that detects a selection signal of the optical transmission line (0 system / 1 system) from the system selection control unit of the master station device, and selection control from 0 system delay data or 1 system delay data according to the selection signal And a delay control unit that controls the transmission timing of the uplink data according to the selected delay data, and an optical transmission / reception unit that transmits the uplink data to the master station device.

[0014]

DISCLOSURE OF THE INVENTION The conventional TDM described above
In a communication system adopting the A system, since the propagation delay guard time is fixed, when the communication partner station (reference station or subscribing station) is at a distance exceeding the propagation delay guard time, the transmitting station sets the reference frame Even if synchronization is possible, when the transmission data arrives at the communication partner station, as shown in the reception data D2 of FIG. 5, the communication partner station cannot receive the data normally because the reception data does not fit in the frame. There are cases. When such a situation occurs, the receiving station makes a retransmission request, and the transmitting station repeats the retransmission until the receiving station normally receives it, which hinders effective use of the time slot.

The present invention has been made in order to solve the above-mentioned problem, and its object is to provide data in the TDMA system even when the communication partner station is at a distance exceeding the propagation delay guard time. It is an object of the present invention to provide a transmitting / receiving device, a communication system and a propagation delay control method capable of transmitting / receiving normally.

[0016]

In order to achieve the above object, a transmitting / receiving apparatus according to a first aspect of the present invention includes a calculating section for calculating a propagation delay time of a received signal, and a calculating section for calculating the propagation delay time. When the specified propagation delay time is greater than the propagation delay guard time, a propagation delay excess detection command indicating that is transmitted, and when a propagation delay excess detection command indicating that the propagation delay time is greater than the propagation delay guard time is received Is
And a control unit that advances the transmission timing of the transmission data.

In the transmission / reception apparatus according to the first aspect of the present invention, the calculation unit includes a synchronization detection unit that detects a synchronization signal based on a reference frame, and a frame based on the synchronization signal detected by the synchronization detection unit. A frame generation unit that generates a signal, and a delay monitor unit that calculates a propagation delay time by measuring the time from when the frame signal from the frame generation unit is received until the synchronization signal from the synchronization detection unit is received. And, the transmission of the propagation delay excess detection command in the control unit can be configured to be performed when the propagation delay time calculated by the delay monitor unit is longer than the propagation delay guard time.

A communication system according to a second aspect of the present invention includes, for the same purpose as described above, a reference station including the transmitting / receiving device according to the first aspect, and a transmitting / receiving device according to the first aspect. A plurality of subscriber stations and a network connecting the reference station and the plurality of subscriber stations, each of the plurality of subscriber stations being configured to send and receive data to and from the reference station and other subscriber stations. Has been done.

In the communication system according to the second aspect of the present invention, the control unit of the transmission / reception device included in the subscriber station is
When the calculated propagation delay time is larger than the propagation delay guard time, a propagation delay excess detection command indicating that is transmitted to the transmission / reception device included in the reference station, indicating that the propagation delay time is larger than the propagation delay guard time. When the propagation delay excess detection command is received from the transmission / reception device included in the reference station, the transmission data transmission timing can be advanced.

In this case, the reference station can be configured to be movable. Further, the reference station may be configured to periodically transmit the reference frame to all of the plurality of subscriber stations.

Further, the propagation delay control method according to the third aspect of the present invention has a first step of calculating a propagation delay time of a received signal and a calculated propagation delay time for the same purpose as above. Is greater than the propagation delay guard time, a propagation delay excess detection command indicating that is transmitted, and when a propagation delay excess detection command indicating that the propagation delay time is greater than the propagation delay guard time is received, the transmission data The second step of accelerating the sending timing.

In the propagation delay control method according to the third aspect of the present invention, the second step includes a step of detecting a sync signal based on a reference frame, and a frame signal generated based on the detected sync signal. And a step of calculating a propagation delay time by measuring the time from the reception of the generated frame signal to the reception of the synchronization signal, the transmission of the propagation delay excess detection command , Can be configured to be performed when the calculated propagation delay time is larger than the propagation delay guard time.

Specifically, the present invention is constructed as follows. That is, the reference station transmits a synchronization signal that serves as a network timing reference in a time slot (TS0) that serves as a synchronization reference frame (see FIG. 4).
Each subscriber station joins the network in synchronization with the reference frame by detecting a synchronization signal included in the reference frame from the reference station and generating timing within itself.

Each subscriber station generates the timing of a channel time slot (CH0 to CHn) for which each subscriber station transmits and receives, based on the synchronized reference frame, and uses the assigned channel time slot to perform channel synchronization. Send the send data along with the pattern. Here, each time slot is provided with a propagation delay guard so that reception can be performed even if a propagation delay occurs in received data.

Subscriber station (reception station) with which the transmission station communicates
And the reference station detects the channel synchronization pattern and calculates the propagation delay within the time slot. If the calculated propagation delay time exceeds the propagation delay guard time,
The receiving station notifies the reference station of the propagation delay excess detection.
The reference station notifies the transmitting station that has transmitted the transmission data in the network control time slot of the deviation of the transmission timing. Further, even when the propagation delay time monitored by itself exceeds the propagation delay guard time, the transmission timing is notified to the transmitting station. The transmitting station controls so that the propagation delay time at the receiving station does not exceed the propagation delay guard time by transmitting the transmission timing earlier by the amount notified by the reference station.

As described above, in the present invention, since the propagation delay is monitored and the transmission timing is notified to the transmitting station, and each subscribing station controls its own transmission timing, all the transmission data within the reception time slot. Is transmitted. As a result, it is possible to suppress the occurrence of discard of the transmission data due to the propagation delay, and to reduce the retransmission of data accompanying it. As a result, the efficiency of network use can be improved. Also, because the propagation delay time detected at the receiving station is shortened, it becomes possible to receive the transmission data from the subscribing station that is distant from the communication partner station normally, and it is possible to expand the coverage area of the network. become.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The transmitter / receiver according to the present invention is configured to be operable as a reference station or a subscriber station.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a transmitting / receiving apparatus according to Embodiment 1 of the present invention.
This transmission / reception device includes an antenna 1, a switching unit 2, a demodulation unit 3,
A synchronization detection unit 4, a frame generation unit 5, a clock extraction unit 6,
Delay monitor unit 7, control unit 8, transmission timing control unit 9,
It is composed of a data generator 10 and a modulator 11.
The calculator of the present invention corresponds to the synchronization detector 4, the frame generator 5, and the delay monitor 7.

The antenna 1 emits the signal from the switch 2 as a radio signal into the air and receives the radio signal from the air and sends it to the switch 2.

The switch 2 switches between transmitting the transmission signal from the modulator 11 to the antenna 1 or transmitting the signal from the antenna 1 to the demodulator 3 and the synchronization detector 4 as a reception signal.

The demodulation section 3 demodulates the radio signal received by the antenna 1. Specifically, the demodulation unit 3 demodulates the reception signal sent from the antenna 1 via the switch 2 based on the frame signal from the frame generation unit 5 and the clock signal CLK from the clock extraction unit 6. . The signal demodulated by the demodulation unit 3 is sent as reception data to a circuit (not shown) in the subsequent stage and also to the control unit 8. As the demodulation unit 3, various types of demodulators can be used according to the adopted modulation method, but since it is not directly related to the feature of the present invention that controls the propagation delay by changing the transmission timing, Detailed description is omitted.

The synchronization detector 4 detects the synchronization signal of the reference frame and the channel synchronization pattern of the data received in each time slot from the radio signal received by the antenna 1. Specifically, when the reception signal is sent from the antenna 1 via the switch 2, the synchronization detection unit 4 synchronizes the reception signal with the synchronization pattern and the channel synchronization of the synchronization signal of the predetermined reference frame TS0. Correlation calculation with the pattern is performed to detect the correlation peak. Then, a synchronization detection signal is generated from the timing of the detected correlation peak to generate the clock extraction unit 6, the frame generation unit 5, and the delay monitor unit 7.
Send to.

The clock extraction unit 6 extracts a transmission / reception clock from the synchronization pattern and the reception signal detected by the synchronization detection unit 4. Specifically, the clock extraction unit 6 generates the clock signal CLK from the received signal and the synchronization detection signal from the synchronization detection unit 4, and the demodulation unit 3, the frame generation unit 5, the delay monitor unit 7, and the transmission timing control unit 9 are provided. Supply to.

The frame generation unit 5 includes a timing and clock extraction unit 6 for the reference frame detected by the synchronization detection unit 4.
The timing of the transmission / reception channel of the TDMA frame is generated from the transmission / reception clock extracted in. In particular,
The frame generation unit 5 generates a reference frame and a frame signal of a transmission / reception channel based on the synchronization detection signal from the synchronization detection unit 4 and the clock signal CLK from the clock extraction unit 6. The frame signal generated by the frame generator 5 is supplied to the demodulator 3, delay monitor 7, controller 8 and transmission timing controller 9.

The delay monitor section 7 calculates the propagation delay time by comparing the timing of the synchronization pattern detected by the synchronization detection section 4 with the timing of the transmission / reception channel from the frame generation section 5. More specifically, the delay monitor unit 7 receives the clock signal C after receiving the frame signal from the frame generation unit 5 and then receiving the synchronization detection signal from the synchronization detection unit 4 in each time slot.
LK is counted and the propagation delay time of the received signal is calculated. Then, the calculated propagation delay time and the propagation delay guard time are compared, and when the propagation delay time exceeds the propagation delay guard time, a propagation delay excess detection signal indicating that and a clock for the excess time. The signal CLK is supplied to the control unit 8.

When the propagation delay time calculated by the delay monitor unit 7 exceeds the propagation delay guard time, the control unit 8 notifies the transmitting station using the time slot that the propagation delay guard time has passed. To control the transmission. Further, when the notification of the transmission timing delay is received by the reception signal, the timing control start and the timing to be adjusted are notified to the transmission timing control unit 9.

That is, the control unit 8 extracts the transmission timing control request and the control timing length data from the received data sent from the demodulation unit 3 and detects the propagation delay excess detection sent from the delay monitor unit 7. The signal and the clock signal CLK for the excess time are input.

When this transmitter / receiver is a subscriber station, when the transmission timing control request and the control timing length data are included in the received data from the reference station, the transmission timing control unit 9 is requested to advance the transmission timing and The timing length data to be controlled is supplied to instruct the adjustment of the transmission timing. In addition, when a delay occurs in the received signal from another subscriber station received on the normal transmission / reception channel, and when the propagation delay excess detection signal is received from the delay monitor unit 7, the transmission of the propagation delay excess detection command is transmitted as data. The generation unit 10 is instructed.

On the other hand, when this transmitter / receiver is the reference station, the data generation request for transmitting the transmission timing control request is transmitted to the subscriber station that has transmitted the reception data in the time slot in which the propagation delay guard time excess has occurred. It is sent to the generation unit 10. Even when a propagation delay excess detection command is detected in the received data, the data for sending the transmission timing control request to the subscriber station that sent the received data in the time slot in which the propagation delay guard time excess has occurred. The generation request is sent to the data generation unit 10.

The transmission timing control section 9 generates the transmission timing synchronized with the received reference frame, and the modulation section 1
The transmission timing of the transmission data output from 1 is controlled. In addition, timing control for the transmission channel is performed according to the frame signal from the frame generation unit 5. Furthermore,
When a transmission timing adjustment instruction is received from the control unit 8, control is performed to advance the transmission timing by the instructed clock.

The data generator 10 normally performs buffering / error control / TDMA control for data transmission, and supplies it to the modulator 11. On the other hand, when an instruction is received from the control unit 8, a message (transmission command data) representing the occurrence of propagation delay guard time excess is generated. Specifically, when the data generation unit 10 receives a transmission timing control request command or a propagation delay excess detection command transmission instruction from the control unit 8, the data generation unit 10 generates a message according to the instruction and sends it to the modulation unit 11. .

The modulator 11 modulates the data from the data generator 10 and transmits the data at the timing based on the instruction from the transmission timing controller 9. It should be noted that various types of modulators can be used as the modulator 11 according to the adopted modulation method, but since it is not directly related to the feature of the present invention that controls the propagation delay by changing the transmission timing, Detailed description is omitted.

Next, the operation of the transmitting / receiving apparatus according to Embodiment 1 of the present invention having the above configuration will be described.

First, an outline of the operation of this transmission / reception device will be described.
This will be described with reference to the sequence diagram shown in FIG. In FIG. 2, two subscriber stations # for one reference station as communication stations #
1 and subscriber station # 2 exist, an example is shown in which data is transmitted from subscriber station # 1 to subscriber station # 2.

The reference station periodically transmits a reference frame to the subscriber stations # 1 and # 2 (S1). Subscriber # 1
Generates a TDMA frame in synchronization with the received reference frame and transmits data to the subscriber station # 2 using the transmission time slot assigned to itself (S2). The subscriber station # 2 detects that a delay has occurred, that is, that the propagation delay time exceeds the propagation delay guard time when it is far from the subscriber station # 1 (S3).

When the subscriber station # 2 detects that a delay has occurred, it generates a delay detection command (propagation delay excess detection command) and transmits it to the reference station (S4). Upon receiving this delay detection command, the reference station generates a transmission timing control command and transmits it to the subscriber station # 1 (S5). Subscriber station # 1 which received this transmission timing control command,
Control so that the data transmission timing is advanced (S
6). By the above operation, even if a delay occurs that exceeds the propagation delay guard time, the subscriber station # 1
Can successfully send data to subscriber # 2.

Next, the operation of the transmission / reception device when performing the above-mentioned data transmission / reception will be described in detail. A radio signal from the communication partner station is received by the antenna 1 and sent to the demodulation unit 3 and the synchronization detection unit 4 via the switch 2. Sync detector 4
When the received signal is input, the synchronous processing for the reference frame is performed by performing a correlation calculation between a predetermined pattern of the synchronization signal of the reference frame and the received signal. The correlation peak timing detected by the correlation calculation is output to the frame generation unit 5.

After synchronizing with the reference frame, that is, T
Since the reference frame is periodically received after joining the DMA network, the synchronization detection unit 4 periodically performs the synchronization process. After joining the network, the synchronization detector 4
Correlation calculation with the channel synchronization pattern is performed to detect the correlation peak for the received signal. Then, a synchronization detection signal is generated from the timing of the detected correlation peak and is supplied to the frame generator 5 and the delay monitor 7.

The frame generator 5 generates a reference frame and a frame signal of a transmission / reception channel based on the clock signal CLK and the synchronization detection signal from the synchronization detector 4. This frame signal is supplied to the demodulation unit 3, the delay monitor unit 7 and the transmission timing control unit 9. As a result, the subscriber station identifies (controls) the channel for transmitting and receiving data.

The delay monitor unit 7 counts the clock signal CLK from the reception of the frame signal from the frame generation unit 5 to the reception of the synchronization detection signal from the synchronization detection unit 4 in each time slot, The propagation delay time of the received signal is calculated. Then, the calculated propagation delay time is compared with the initially set propagation delay guard time. When it is determined by this comparison that the propagation delay time is longer than the propagation delay guard time, the delay monitor unit 7 causes the control unit 8 to
A propagation delay excess detection signal is sent to and the notification that the propagation delay excess detection of the received signal has been made.

The control unit 8 receives the notification of propagation delay excess detection and the number of excess time clocks from the delay monitor unit 7. Also, the transmission timing control request and the control timing length data are extracted from the received data.

Here, when the transmitting / receiving device is a subscriber station, in response to the transmission timing control request in the received data received from the reference station, the control timing length data and the transmission timing based on the control timing length data in the received data are transmitted. A request for advancing is output to the transmission timing control unit 9. When the propagation delay excess detection notification is received from the delay monitor unit 7, the data generation unit 10 is instructed to transmit the propagation delay excess detection command.

On the other hand, when the transmission / reception device is a reference station, when a propagation delay excess detection command is detected in the received data, transmission timing control is performed for the subscriber station transmitting in the time slot in which the propagation delay guard time excess has occurred. A data generation request for transmitting the request is made to the data generation unit 10. When the propagation delay excess detection notification is received from the delay monitor unit 7, the data generation request for transmitting the transmission timing control request is transmitted to the subscriber station that has transmitted the reception data in which the propagation delay guard time excess has occurred. This is performed for the generation unit 10.

The data generator 10 normally performs buffering / error control / TDMA control for data transmission and supplies it to the modulator 11. When the transmission instruction of the transmission timing control request command or the propagation delay excess detection command is received from the control unit 8, the transmission command data according to the instruction is generated and sent to the modulation unit 11.

The transmission timing control unit 9 controls the transmission timing of transmission data. Normally, the timing control for the transmission channel is performed according to the frame signal from the frame generation unit 5, and the transmission control of the modulation unit 11 is performed. When the transmission timing adjustment instruction is received from the control unit 8,
The transmission timing of the instructed clock is advanced to control the transmission of the modulator 11.

The transmitting / receiving apparatus according to the first embodiment of the present invention configured as described above has the following effects. That is, since the transmission / reception device controls the transmission data to be sent out earlier when the propagation delay exceeding the propagation delay guard time occurs, the transmission delay exceeding the propagation delay guard time is controlled. Data can be transmitted and received normally even in the case of occurrence of.

Further, since the transmission / reception device controls the transmission timing by detecting the synchronization of the received signal, the transmission timing control can be performed quickly to the subscriber station transmitting at the timing exceeding the propagation delay guard time as it is, It is possible to reduce the number of retransmission requests and the number of retransmissions due to reception failure due to propagation delay.

Further, since the transmission / reception device can shorten the propagation delay guard time in the transmission format by controlling the transmission timing, the time occupancy of TDMA can be improved.

Further, the transmission / reception apparatus controls the transmission timing from the reference station while shortening the propagation delay guard time, so that the network of the subscriber stations located at a distance such that a propagation delay exceeding the propagation delay guard time occurs from the reference station. It becomes possible to subscribe and the number of subscribers can be increased.

In addition, since the reference station controls the transmission timing of the transmitter / receiver, it is possible to maintain the network subscription of other subscriber stations even when the reference station moves.

Furthermore, since the reference station controls the transmission timing in the transmitter / receiver, the transmission timing including the propagation delay can be adjusted to the reference frame of the reference station, so that all the subscriber stations that have joined the TDMA network can Data can be received.

(Embodiment 2) FIG. 3 is a block diagram showing the configuration of a transmitting / receiving apparatus according to Embodiment 2 of the present invention.
This transmitter / receiver is the same as the transmitter / receiver according to the first embodiment.
It is configured by adding the reception level determination unit 12. In this transmission / reception device, the control of the delay monitor unit 7 is further devised.

The reception level determination unit 12 determines the reception level of the demodulated reception signal from the demodulation unit 3 and sends the determination result to the control unit 8.

Next, the operation of the transmitting / receiving apparatus according to the second embodiment of the present invention configured as described above will be explained.

The demodulation section 3 sends the reception level of the reception signal from the switch 2 to the reception level determination section 12. The reception level determination unit 13 compares the input reception level with a predefined reception level and determines whether the level is within the valid range. The determination result is output to the control unit 8 for each reception channel.

The control unit 8 validates or invalidates the transmission delay excess detection from the delay monitor unit 7 and the transmission timing control request extracted from the received signal according to the determination result from the reception level determination unit 12. To control. That is, when the determination result from the reception level determination unit 12 indicates that it is valid, the operation is the same as that of the first embodiment, but when it indicates that it is invalid, the propagation delay excess detection result and The transmission control by the transmission timing control request is not performed.

As described above, the transmission / reception apparatus according to the second embodiment determines whether the received signal is valid or invalid according to the received signal level. The effective range of the wireless communication network to which the subscribing station that performs transmission control joins can be controlled by controlling so that the transmission control is not performed for the received signal of low level and low reliability.

[0068]

As described in detail above, according to the present invention,
In the TDMA method, it is possible to provide a transmission / reception device, a communication system and a propagation delay control method capable of normally transmitting / receiving data even when a communication partner station exists at a distance exceeding the propagation delay guard time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a transmission / reception device according to a first embodiment of the present invention.

FIG. 2 is a sequence diagram for explaining a schematic operation of the transmitting / receiving apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a transmitting / receiving apparatus according to Embodiment 2 of the present invention.

FIG. 4 is a diagram for explaining a conventional TDMA method.

FIG. 5 is a diagram for explaining a propagation delay in the conventional TDMA method.

[Explanation of symbols]

1 antenna 2 switch 3 demodulator 4 Sync detector 5 Frame generator 6 Clock extractor 7 Delay monitor 8 control unit 9 Transmission timing control unit 10 Data generator 11 Modulator 12 Reception level determination unit

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K028 AA14 BB04 CC05 HH02 MM12                       MM16                 5K047 AA12 BB01 CC06 HH01 HH11                       MM02 MM11 MM56                 5K067 AA14 CC04 DD25 DD30 DD43                       DD44 EE02 EE10 EE16 EE22                       EE72 FF05 FF16 GG01 HH22

Claims (8)

[Claims] 1. A calculation unit for calculating a propagation delay time of a received signal, and, when the propagation delay time calculated by the calculation unit is longer than a propagation delay guard time, a propagation delay excess detection command indicating that fact. A transmission / reception apparatus comprising: a control unit that advances the transmission timing of transmission data when transmitting and receiving a propagation delay excess detection command indicating that the propagation delay time is longer than the propagation delay guard time. 2. The calculation unit includes a synchronization detection unit that detects a synchronization signal based on a reference frame, a frame generation unit that generates a frame signal based on the synchronization signal detected by the synchronization detection unit, and the frame generation unit. A delay monitor unit that calculates a propagation delay time by measuring a time from receiving a frame signal from the synchronization unit to receiving a synchronization signal from the synchronization detection unit, and a propagation delay excess in the control unit. The transmission / reception device according to claim 1, wherein the transmission of the detection command is performed when the propagation delay time calculated by the delay monitor unit is longer than the propagation delay guard time. 3. A reference station including the transceiver according to claim 1 or 2, a plurality of subscriber stations each including the transceiver according to claim 1 or 2, and the reference station and the plurality of subscribers. A communication system comprising a connecting network, wherein each of the plurality of subscriber stations transmits and receives data to and from the reference station and another subscriber station. 4. When the calculated propagation delay time is larger than the propagation delay guard time, the control unit of the transmission / reception device included in the subscriber station transmits / receives a propagation delay excess detection command indicating that fact to the transmission / reception included in the reference station. The transmission timing of transmission data is advanced when the transmission delay excess detection command indicating that the propagation delay time is larger than the propagation delay guard time is received from the transmission / reception device included in the reference station. Communication system. 5. The communication system according to claim 4, wherein the reference station is configured to be movable. 6. The communication system according to claim 5, wherein the reference station periodically transmits a reference frame to all of the plurality of subscriber stations. 7. A first step of calculating a propagation delay time of a received signal, and when the calculated propagation delay time is larger than a propagation delay guard time, a propagation delay excess detection command indicating that is transmitted. , When a propagation delay excess detection command indicating that the propagation delay time is larger than the propagation delay guard time is received,
A second step of advancing the transmission timing of transmission data, and a propagation delay control method. 8. The second step comprises: detecting a sync signal based on a reference frame; generating a frame signal based on the detected sync signal; and receiving the generated frame signal. Calculating the propagation delay time by measuring the time until the synchronization signal is received, and, the transmission of the propagation delay excess detection command, the calculated propagation delay time from the propagation delay guard time The propagation delay control method according to claim 7, which is performed when the value is large.