JP2023121408A - Radio transmission system - Google Patents

Abstract

To provide a radio transmission system configured, in sequentially transmitting transmission data to be transmitted across multiple frames, to allow a receiving side to easily identify that pieces of data are identical, and enable combination of normal data, thereby improving a reception rate.SOLUTION: In a radio transmission system, a transmission apparatus sequentially transmits transmission data across multiple frames, when the transmission data is transmitted across the frames, including a check code for confirming an error of data within the frames in each of the frames. A mobile station device 4 or a base station device 3, serving as a receiving device, receives the transmission data a plurality of times. When an error data detection unit 32 detects an error in the transmission data, a data comparison/replacement unit 34 selects frames determined to be non-defective with the check code, in the multiple pieces of received transmission data, and synthesizes the selected frames by combination, to generate normal transmission data.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a radio transmission system, and more particularly to a radio transmission system capable of improving the reception rate of correct reception without errors when transmitting data transmitted over a plurality of frames in succession a plurality of times.

[Description of prior art: FIG. 7]
A schematic configuration of a radio transmission system used in a business radio system will be described with reference to FIG. FIG. 7 is a schematic configuration diagram of a general radio transmission system.
As shown in FIG. 7, the radio transmission system includes a plurality of command consoles 1-1 to 1-n (hereinafter simply referred to as command console 1 when n is not distinguished), which are upper stations, a line controller 2, It comprises a plurality of base station devices 3-1 to 3-n (hereinafter simply referred to as base station device 3 when n is not distinguished) and a plurality of mobile station devices 4. FIG.

A command console 1 is connected to a line control device 2 and monitors and controls a radio transmission system or integrally monitors and controls a plurality of systems.
In addition, the command console 1 performs communication and data transmission/reception with the mobile station device 4 via the line control device 2 .

The line control device 2 is connected to the command console 1 and the base station device 3 and performs exchange control in communication between the command console 1 and the mobile station device 4 .
The base station device 3 is wired-connected to the line control device 2 and wirelessly connected to the mobile station device 4 to perform data transmission.

The mobile station device 4 is a wireless communication terminal that is configured by a vehicle-mounted wireless device or a portable wireless device, and that can be operated while moving or in a fixedly installed state. The mobile station device 4 performs data transmission by wireless communication with the base station device 3 within the service area of the base station device 3 . Here, radio communication from the base station device 3 (upper device) to the mobile station device 4 (lower device) is called down transmission, and radio communication in the opposite direction from the mobile station device 4 to the base station device 3 is called up communication. .

[Conventional data transmission]
In the radio transmission system as shown in FIG. 7, data is transmitted from the mobile station device 4 to the base station device 3 and from the base station device 3 to the mobile station device 4 using radio (radio waves).
Since radio waves propagate in space in a wireless section, it is assumed that the transmission data will not be correctly propagated to the target device due to the influence of shielding and reflection by topography and buildings.

Conventionally, in some cases, a method of decoding data is implemented by an error correction technique such as partitioning data and creating new data from the partitioned data according to a certain rule.
However, in error correction, if there is an error in all of the received data, all the data must be discarded.

Also, when the amount of data to be transmitted becomes large, it is necessary to transmit the data over a plurality of frames during transmission.
When the data is transmitted over a plurality of frames, the longer the data length, the longer the propagation time. Therefore, it is more susceptible to the influence of the propagation environment such as changes in the surrounding environment.

Furthermore, conventionally, by performing continuous transmission in which the same data is continuously transmitted multiple times, the receiving side generates normal data from multiple data, and the reception rate (transmission arrival rate) at which the data is received normally There was something to improve.

[Example of conventional bit allocation: Fig. 8]
An example of conventional bit allocation when transmitting data over a plurality of frames will be described with reference to FIG. FIG. 8 is an explanatory diagram showing an example of bit allocation in a conventional radio transmission system. FIG. 8 shows an example of bit allocation and a transmission frame of a fast associated control channel (FACCH) in a physical communication channel when data is transmitted using radio.

If the data to be transmitted is long and cannot be accommodated in one frame, the number of frames is increased according to the data length and transmitted. In the example of FIG. 8, the transmission data is accommodated across N frames from the first frame 301-1 to the last frame 301-N.
In the first frame 301-1, octet 1 stores signal configuration information such as a frame number, octets 2 and 3 store additional signal type information including information for specifying transmission data, and octets 4 to 301-1. 13 stores transmission data.

In the intermediate frames 301-2 to 301-N-1, octet 1 stores signal configuration information, and octets 2 to 13 store transmission data.
In the final frame 301-N, octet 1 stores signal configuration information, octets 2 to 12 store transmission data, and octet 13 stores a check code.
Conventionally, only the final frame 301-N is provided with a check code, and the presence or absence of an error is detected in the entire data of the first frame 301-1 to the final frame 301-N.

During transmission, the head frame 301-1 is stored in the transmission frame 1, the intermediate frame 301-2 is stored in the transmission frame 2, and then the last frame 301-N is stored in the transmission frame N. stored and transmitted.

[For continuous transmission: Fig. 9]
Next, a transmission frame for continuous transmission will be described with reference to FIG. FIG. 9 is an explanatory diagram showing an example of continuous transmission in a conventional wireless transmission system. Incidentally, FIG. 9 shows an example in which the transmission data is accommodated across five frames from the first frame 301-1 to the last frame 301-5. Also, here, the case of two consecutive transmissions in which the same data is transmitted twice in succession is shown.

As shown in FIG. 9, in the first transmission of two consecutive transmissions, similarly to FIG. show). In the second transmission, following the data in the first transmission, the data is stored in transmission frames 6 to 10 in order (indicated by a two-dot dashed line) and transmitted.

[Loss in transmission over multiple frames]
However, when transmission is performed over a plurality of frames, if the leading frame 301-1 containing the data type is lost, the signal type of the transmission data becomes unknown, and one data cannot be decoded and is discarded. There is also Even if continuous transmission is performed, the same is true if loss occurs in the first frame in all of the multiple transmissions.
In other words, even if the data loss occurs only in the first frame, all the data will be discarded, resulting in poor data transmission efficiency.

[Related technology]
Incidentally, as a prior art related to the radio transmission system, there is Japanese Unexamined Patent Application Publication No. 2000-59345 "Data Receiving Apparatus Using Radio Line" (Patent Document 1).
Patent Literature 1 describes generating normal data from a plurality of consecutively transmitted or retried data to increase the data reception rate.

JP-A-2000-59345

As described above, in conventional wireless transmission systems, when transmission data is transmitted across multiple frames, even if errors occur in some frames due to the propagation environment, the entire transmission data is retransmitted instead of frame by frame. Therefore, there is a problem that the data transmission efficiency is poor.

In particular, when an error occurs in the leading frame, all the data of the plurality of frames must be discarded without using the frames that have been received normally, resulting in poor efficiency.

In addition, in Patent Document 1, when a transmission device transmits transmission data over a plurality of frames, each frame contains the same sequence number and a check code for the frame and is transmitted multiple times. By referring to the check code for each frame of a plurality of received data, error-free frame data is combined and synthesized from received data with the same sequence number, and the synthesized data is decoded or retransmitted in frame units. Outputting the request is not described.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned actual situation. data can be combined to obtain normal data, and if there is an error frame in any of the consecutively transmitted transmission data, a retransmission request is output for each frame to improve the reception rate. It is an object of the present invention to provide a radio transmission system capable of shortening the data transmission time associated with retransmission.

The present invention, which solves the problems of the conventional example, is a wireless transmission system that performs data transmission using wireless communication. A transmission device that transmits the transmission data multiple times, including a check code for checking the error of the data in the frame, and a transmission that receives the transmission data multiple times and detects an error in the transmission data. and a receiver that selects error-free frames from data based on check code determination, and combines the selected frames to generate normal transmission data.

Further, according to the present invention, in the wireless transmission system described above, the transmitting device assigns a sequence number to each frame in the transmission data, and the receiving device determines the sequence number, and configures frames related by the sequence number. It is characterized by recognizing transmission data.

Further, in the wireless transmission system of the present invention, when the receiving device cannot generate normal transmission data even if error-free frames are selected, the receiving device requests the transmitting device to resend the frames lacking in the generation. In response to a frame retransmission request, the transmitting device retransmits the frame to the receiving device, and the receiving device generates normal transmission data using the retransmitted frame.

Further, in the wireless transmission system of the present invention, the receiving device requests the transmitting device to retransmit a frame having an error in the first received transmission data, and the transmitting device receives the retransmission request for the frame. The apparatus is characterized in that the frame is retransmitted multiple times, and the receiving apparatus generates normal transmission data using the frame that has been retransmitted multiple times.

According to the present invention, in a wireless transmission system that performs data transmission using wireless communication, when transmission data to be transmitted spans a plurality of frames, an error in the data within each frame is confirmed. A transmission device that transmits the transmission data multiple times, including the check code that Since the radio transmission system has a receiver that selects error-free frames and combines the selected frames to generate normal transmission data, it is possible to determine whether each frame is normal or has an error. Even if the data are all erroneous, by combining normal frames among them, normal transmission data can be generated, and the reception rate can be improved.

Further, according to the present invention, the transmitting device assigns a sequence number to each frame in the transmission data, and the receiving device determines the sequence number and recognizes the transmission data composed of related frames by the sequence number. Therefore, even if the first frame of the transmission data received multiple times is all erroneous, the data can be specified from the sequence numbers of other frames and a retransmission request can be made, and normal transmission can be performed. This has the effect of increasing the possibility of generating data and improving the reception rate.

Further, according to the present invention, when the receiving device cannot generate normal transmission data even if error-free frames are selected, the receiving device requests the transmitting device to resend the frames that are insufficient for the generation. In response to a frame resend request, the frame is resent to the receiving device, and the receiving device uses the resent frame to generate normal transmission data. It enables retransmission in units, shortens the transmission time associated with retransmission, reduces the possibility of error occurrence, and has the effect of improving the reception rate.

Further, according to the present invention, the receiving device requests the transmitting device to retransmit a frame having an error in the first received transmission data, and the transmitting device responds to the frame retransmitting request by sending the receiving device are retransmitted a plurality of times, and the receiving device generates normal transmission data using the frames that have been retransmitted multiple times. By making a retransmission request, it is possible to quickly obtain a normal frame and generate normal transmission data in a short period of time.

1 is an explanatory diagram showing a schematic configuration of a base station apparatus; FIG. FIG. 4 is an explanatory diagram showing an example of bit allocation in this wireless transmission system; FIG. 10 is an explanatory diagram showing an example of data interpolation by continuous transmission (in the case of successful interpolation); FIG. 11 is an explanatory diagram showing an example of data interpolation by continuous transmission (in case of interpolation failure); 4 is a flow chart showing processing of an error data detection unit; 9 is a flow chart showing processing of a data comparison/replacement unit; 1 is a schematic configuration diagram of a general wireless transmission system; FIG. FIG. 4 is an explanatory diagram showing an example of bit allocation in a conventional radio transmission system; FIG. 10 is an explanatory diagram showing transmission frames in the case of continuous transmission in a conventional wireless transmission system;

An embodiment of the present invention will be described with reference to the drawings.
[Outline of Embodiment]
In a radio transmission system (this radio transmission system) according to an embodiment of the present invention, when transmission data to be transmitted spans a plurality of frames, a data error in the frame is detected in each frame. Transmission data that spans multiple frames, including a check code to be confirmed, is transmitted (continuously) multiple times, and if the receiving device receives the transmission data multiple times and there is an error in the transmission data, it is received multiple times. Error-free frames are selected from the transmission data by checking the check code, and the selected frames are combined to generate normal transmission data. , the possibility of obtaining normal transmission data can be increased, and the reception rate can be improved.

In addition, in this wireless transmission system, the transmitting device attaches the same sequence number to each frame in the transmission data and transmits it, and the receiving device identifies the related frame based on the sequence number and transmits the data over a plurality of frames. It recognizes transmission data, and when transmission data that spans multiple frames is received multiple times, each transmission data can be clearly identified. can also identify erroneously transmitted data based on the sequence number and can be combined using error-free frames.

Furthermore, in this wireless transmission system, when the receiving device cannot generate normal transmission data even if it selects error-free frames, it requests retransmission of the missing frames on a frame-by-frame basis. It retransmits frames, shortens the transmission time associated with retransmission, and reduces the probability of error occurrence.

[Configuration of this wireless transmission system]
Since the basic configuration of this radio transmission system is the same as that of the radio transmission system shown in FIG. 7, the same reference numerals are used for explanation. However, the base station apparatus 3 and the mobile station apparatus 4 that perform wireless communication are different in configuration and processing during transmission and reception.
Further, as will be described later, the line control device 2 may also perform new processing upon reception from the base station device 3 .

In this wireless transmission system, the data length of the transmission data is long, and the operation when the transmission device transmits multiple times across multiple frames (continuous transmission) and the transmission data received multiple times by the reception device are error-free. It is characterized by the operation of extracting error-free frames from the received transmission data and combining them to generate synthesized data when there is a

[Configuration of base station apparatus according to embodiment: FIG. 1]
The configuration of the base station apparatus of this radio transmission system will be described with reference to FIG. FIG. 1 is an explanatory diagram showing a schematic configuration of a base station apparatus. Here, the base station apparatus 3 is shown as an example of the transmitting/receiving apparatus of this wireless transmission system, but the mobile station apparatus 4 also has similar components.
In other words, the base station apparatus 3 and the mobile station apparatus 4 have the configuration of both the transmitting apparatus and the receiving apparatus described in the claims.
It should be noted that FIG. 1 shows only the parts related to the present invention, and the other parts are omitted because they are the same as those of the conventional art.

As shown in FIG. 1, the base station apparatus 3 of this radio transmission system includes a radio reception section 31, an error data detection section 32, a data decoding section 33, a data comparison and replacement section 34, a transmission processing section 35, A wireless transmission unit 36 is provided.
Among these, the radio receiving section 31, the data decoding section 33, and the radio transmitting section 36 have the same configuration and operation as conventional ones.
The radio receiver 31 demodulates the received signal received by the antenna.
Also, the data decoding unit 33 decodes the input data and outputs transmission data.

Error data detector 32 detects whether or not there is an error in the demodulated received data.
Specifically, first, when transmission data spanning a plurality of frames is input, the error data detection unit 32 holds the transmission data until the final frame is input, and converts the transmission data as a whole based on the check code of the final frame. Check for errors. Then, if there is no error, the entire transmission data is transferred to the data decoding section 33 .
Also, if there is an error in the check code of the last frame and the same transmission data has not already been output to the data decoding section 33 , the transmission data is transferred to the data comparison and replacement section 34 .

Furthermore, when error-free synthesized data is input from the data comparison/replacement unit 34 , the error data detection unit 32 outputs the synthesized data to the data decoding unit 33 .
Furthermore, when receiving a retransmission request instruction from the data comparison/replacement unit 34, the error data detection unit 32 transmits the signal type and the sequence number of the received data as information for specifying the transmission data for which retransmission is requested. Output to the processing unit 35 .
The processing of the erroneous data detector 32 will be described later.

The data comparison/replacement unit 34 extracts and combines normal frame data from a plurality of erroneous transmission data that are successively sent, generates error-free synthetic data, and decodes the data through the error data detection unit 32 . It outputs to the unit 33 .
At that time, based on the sequence number in each frame, the data comparison/replacement unit 34 recognizes that the multiple frames are related to each other and constitute one piece of transmission data, even if the data spans multiple frames. Extracting and combining normal portions from a plurality of pieces of transmission data is sometimes called data interpolation.

Specifically, when erroneous transmission data is input, the data comparison/replacement unit 34 checks whether or not there is an error in the transmission data using a frame check code, which will be described later, sequentially from the first frame.
In the case of two consecutive transmissions, the data comparison/replacement unit 34 incorporates data of a frame determined to have no error in the transmission data of the first transmission into the synthesized data.

Then, when the data comparison/replacement unit 34 recognizes the second transmission data based on the sequence number, the frame check code of the second transmission data is correct or incorrect for the frame that could not be acquired in the first transmission data. is determined, and if it is normal, it is incorporated into the synthesized data. When the data of all frames can be acquired, the combined data is output to the data decoding section 33 .

Also, if there is a frame that cannot be acquired even if the transmission data for the second transmission is interpolated, the data comparison/replacement unit 34 outputs a retransmission request instruction to the erroneous data detection unit 32 .
At this time, as a feature of this wireless transmission system, the data comparison/replacement unit 34 requests retransmission in units of frames, and requests retransmission only for necessary frames.

As a result, in this wireless transmission system, even if the top frame of all of the transmission data that has been input is erroneous, the data comparison/replacement unit 34 can identify the transmission data by the sequence number. It is capable of outputting a retransmission request.
The processing of the data comparison/replacement unit 34 will be described later.

Upon receiving the retransmission request from the error data detection unit 32 , the transmission processing unit 35 generates a retransmission request message for the transmission data and outputs the message to the wireless transmission unit 36 .
Further, when transmitting input transmission data spanning a plurality of frames, the transmission processing unit 35 of this wireless transmission system assigns the same sequence number to each frame when generating a telegram, A frame check code for detecting the presence or absence of errors is inserted and transmitted.
The radio transmission unit 36 modulates the message for transmission and transmits it as a radio signal via an antenna.

[Example of bit allocation in this wireless transmission system: Fig. 2]
Next, an example of FACCH bit allocation in this radio transmission system will be described with reference to FIG. FIG. 2 is an explanatory diagram showing an example of bit allocation in this wireless transmission system.
As shown in FIG. 2, it shows transmission data spanning five frames from the first frame 401-1 to the last frame 401-5. A sequence number (denoted as "SN" in the figure) is stored in the type.
The signal configuration information and transmission data of each frame and the check code of the final frame are stored in the same manner as in the conventional wireless transmission system shown in FIGS.

The sequence number is a characteristic part of this wireless transmission system, and is a number for identifying transmission data transmitted from the transmission device.
Specifically, a sequence number is a number that is inserted when transmission data that spans multiple frames is transmitted by a transmission device. A sequence number is attached.
When the same data is sent continuously, the sequence number will also be the same number.

In the first transmission during continuous transmission, the transmitting device transmits the first frame 401-1 to the last frame 401-5 of the transmission data as transmission frames 1 to 5 (dotted lines). is transmitted in transmission frames 6 to 10 (two-dot dashed line).

As a result, the receiving device can easily recognize that a series of data transmitted over a plurality of frames is one piece of data, or that data that is continuously transmitted and received a plurality of times is the same data. be.
In particular, when there is an error in the first frame, the data can be specified and a retransmission request can be made for each frame, thereby improving the possibility of obtaining normal transmission data.

Furthermore, this radio transmission system stores a frame check code for checking whether or not there is an error in the data of each frame.
As shown in FIG. 2, the frame check code is stored in octet 13 for the first frame 401-1 to intermediate frame 401-4, and in octet 12 for the last frame 401-5.

As a result, even if the data is determined to be erroneous by the check code of the last frame in the receiving device, it is possible to determine whether or not there is an error for each received frame, and to select and synthesize error-free frames. It can be incorporated into the data to increase the likelihood that multiple erroneous transmissions will be used to generate error-free synthetic data.

[Example of data interpolation by continuous transmission (in the case of successful interpolation): Fig. 3]
Next, an example of data interpolation in the data comparison/replacement unit 34 of the receiving device will be described with reference to FIG. FIG. 3 is an explanatory diagram showing an example of data interpolation by continuous transmission (in the case of successful interpolation).
As shown in FIG. 3, in the data comparison and replacement unit 34, the error data detection unit 32 detects the first transmission data (continuous transmission data 1) and the second transmission data (continuous transmission data 1) to which the same sequence number is attached. When the continuous transmission data 2) is input, the presence or absence of an error is determined for each frame using a frame check code for each continuous transmission data. Then, the data of the normally received frame is incorporated into the synthesized data.
Synthetic data is generated corresponding to the sequence number.

In the example of FIG. 3, in the continuous transmission data 1, the leading frame, intermediate frame 2, and intermediate frame 3 are normal, so the data comparison/replacement unit 34 incorporates the data of these frames into the synthesized data.
However, since the intermediate frame 1 and the final frame are errors, they are not included in the synthesized data.

Therefore, the data comparison and replacement unit 34 checks the frame check codes of the intermediate frame 1 and the final frame of the continuous transmission data 2, and if they are normal, incorporates the intermediate frame 1 and the final frame of the continuous transmission data 2 into the combined data.
As a result, the transmission data is normal synthesized data, and the data comparison/replacement unit 34 transfers the synthesized data to the data decoding unit 33 via the error data detection unit 32, and the synthesized data is decoded. be.

[Example of data interpolation by continuous transmission (when interpolation fails): Fig. 4]
Next, a case where normal data cannot be obtained even if the data comparison/replacement unit 34 performs data interpolation (interpolation failure) will be described with reference to FIG. FIG. 4 is an explanatory diagram showing an example of data interpolation by continuous transmission (in the case of interpolation failure).
As shown in FIG. 4, in continuous transmission data 1, when the leading frame and intermediate frames 2 and 3 are normal, and the intermediate frame 1 and the final frame are in error, the data comparison/replacement unit 34 replaces the normal leading frame and the data of the intermediate frames 2 and 3 are incorporated into the synthesized data.
Based on the frame check code of the continuous transmission data 2, the correctness of each frame is determined.

As a result of the check, if it is determined that the intermediate frame 2 and the last frame are normal, and the first frame and the intermediate frames 1 and 3 are determined to be erroneous, the data comparison/replacement unit 34 incorporates the data of the last frame that was normal into the synthesized data.
However, since both data 1 and 2 of the intermediate frame 1 have an error, they cannot be incorporated into the synthesized data, and the data cannot be decoded.

Therefore, the data comparison/replacement unit 34 outputs a retransmission request instruction for the intermediate frame 1 to the erroneous data detection unit 32 .
Upon receiving the retransmission request instruction, the erroneous data detection unit 32 attaches a sequence number for specifying the transmission data, and instructs the transmission processing unit 35 to make the retransmission request.
Upon receiving the instruction, the transmission processing unit 35 transmits a retransmission request for the transmission data to the transmission source device (transmission device).

Upon receiving the retransmission request, the transmitting device retransmits the designated frame of the transmission data.
At that time, the transmitting device assigns the same sequence number as the original transmission data to the frame to be retransmitted. As a result, the data comparison/replacement unit 34 of the receiving device recognizes which data is retransmitted, checks normality/error for each frame of the retransmitted data, and if normal, uses it to generate synthesized data. is possible.

In this way, in this wireless transmission system, when retransmitting, it is possible to retransmit only the necessary frames rather than the entire long data spanning multiple frames, shortening the transmission time associated with retransmissions and reducing the probability of transmission errors. , which can improve the reception rate.

In particular, conventionally, if all of the leading frames were erroneous even after continuous transmission, it was necessary to retransmit the entire transmission data. After the frames that were normal are incorporated into the combined data, if the head frame is requested to be retransmitted and acquired, decoding becomes possible, and the transmission efficiency and reception rate can be improved.

As another operation, the data comparison/replacement unit 34, for example, at the stage where an error occurs in the intermediate frame 1 and the final frame of the continuous transmission data 1, does not wait for the continuous transmission data 2 to be checked, and replaces the two frames. A retransmission request instruction may be output so as to be transmitted.
The retransmission request may be configured such that the retransmission from the transmitting device is performed in succession, or may be performed in one transmission. Further, the retransmission request itself from the receiving device may be transmitted continuously or may be transmitted once.

[Processing of erroneous data detector 32: FIG. 5]
Next, the processing in the error data detector 32 when transmission data is received will be described with reference to FIG. FIG. 5 is a flow chart showing the processing of the erroneous data detector. Here, an example will be described in which transmission data is transmitted continuously (for example, two consecutive transmissions) from the transmission side.
As shown in FIG. 5, when transmission data is input from the radio reception unit 31 (S11), the error data detection unit 32 checks the sequence number (S12), and based on the check code of the last frame, detects the transmission data. It is determined whether the data is normal (S13).

In the process S13, if the transmission data is normal (Yes), the error data detection unit 32 outputs the transmission data to the data decoding unit 33 (S14), and the process ends. If the transmission data with the same sequence number has already been determined to be normal and has been output to the data decoding unit 33, the transmission data may be discarded without being output to the data decoding unit 33. FIG.
In other words, if the data of continuous transmission 1 is normal, the data of continuous transmission 2 may be discarded without being decoded.

If the transmission data is not normal in the process S13 (No), the error data detector 32 determines whether the transmission data with the same sequence number has already been determined to be normal (S15), If the transmission data with the same sequence number has not yet been determined to be normal (if No), the transmission data is output to the data comparison/replacement unit 34 (S16), and the process ends.

If the transmission data with the same sequence number has already been determined to be normal (Yes) in step S15, the error data detection unit 32 does not output the transmission data to the data comparison and replacement unit 34. It is discarded (S20) and the process ends.

That is, the transmission data of the continuous transmission 1 is output to the data decoding unit 33 if normal, and is output to the comparison and replacement unit 34 if there is an error.
On the other hand, if the transmission data of the continuous transmission 2 is normal, it is output to the data decoding unit 33 only when the data of the continuous transmission 1 has an error. At this time, the error data detection unit 32 may output an instruction to the data comparison/replacement unit 34 to discard the transmission data of the consecutive transmission 1 having the same sequence number that has already been input.
Even if the transmission data of the continuous transmission 2 is normal, it may be discarded when the data of the continuous transmission 1 is normal.
Also, if the transmission data of the continuous transmission 2 is an error, it is output to the comparison/replacement unit 34 only when the transmission data of the continuous transmission 1 is an error, and if the transmission data of the continuous transmission 1 is normal, discarded.

If there is an error in the transmission data that is not transmitted continuously, the error data detection unit 32 discards the transmission data without outputting it to the comparison replacement unit 34, and requests the transmission processing unit 35 to resend the entire data. to output
In this way, the processing of the error data detector 32 is performed.

[Processing of data comparison and replacement unit 34: FIG. 6]
Next, the processing of the data comparison/replacement unit 34 will be described with reference to FIG. FIG. 6 is a flow chart showing the processing of the data comparison/replacement unit.
As shown in FIG. 6, the data comparison/replacement unit 34 receives erroneous continuous transmission data from the error data detection unit 32 (S21), and checks the sequence number (S22). Here, the data comparison/replacement unit 34 counts the number of consecutively transmitted data with the same sequence number.

Then, the data comparison/replacement unit 34 uses the frame check code to determine normality/error for each frame of the continuous transmission data (S23), and uses the data of the normal frame as data of the combined data of the sequence number. Take in (S24).

Then, the data comparison/replacement unit 34 determines whether or not the data of all the frames have been fetched into the combined data (S25). output to the data decoding unit 33 via the

In the process S25, if the fetching is not completed (if No), the data comparison/replacement unit 34 determines whether or not all the consecutively sent data have been checked (two in the case of two consecutively sent) (S27). ), and if continuous transmission data still remains (if No), the process returns to step S21 and waits for input of the next continuous transmission data.

At that time, a limit is set for the waiting time of the continuous transmission data of the same sequence number, and if a timeout occurs, the data comparison/replacement unit 34 discards the continuous transmission data and terminates the process. good too. As a result, even if the data of continuous transmission 1 is erroneously input to the data comparison/replacement unit 34, if the data of continuous transmission 2 is normal and is output to the data demodulation unit 33, the processing for the sequence number is performed. It can be finished.
Alternatively, in the error data detection unit 32, if the data of the continuous transmission 1 with the same sequence number is erroneous and the data of the continuous transmission 2 is normal, the error data detection unit 32 instructs the data comparison and replacement unit 34 to It may be instructed to discard the consecutively transmitted data of the sequence number.

In addition, in the process S27, when all the continuously transmitted data are checked (if YES), the data comparison/swap unit 34 detects the missing frame in the error data detection unit 32 (all continuously transmitted data is detected as an error). For the frame that has not been received, a retransmission request instruction is output (S28), and the process ends.
In this manner, the processing of the data comparison/replacement unit 34 is performed.

[Effects of Embodiment]
According to this wireless transmission system, when the transmission data to be transmitted extends over a plurality of frames, each frame includes a check code for checking an error in the data in the frame. Straddling transmission data is transmitted (continuously) a plurality of times, and the base station device 3 or mobile station device 4, which is a receiving device, receives the transmission data a plurality of times, and the error data detector 32 detects an error in the transmission data. When it detects that there is an error, it outputs it to the data comparison and replacement unit 34, and the data comparison and replacement unit 34 selects error-free frames from among the transmission data received a plurality of times by checking the check code, and combines the selected frames. To improve the reception rate by increasing the possibility of obtaining normal transmission data even when an error occurs in each of the successively transmitted transmission data. There is an effect that can be done.

Further, according to this wireless transmission system, the transmitting device attaches the same sequence number to each frame in the transmission data and transmits it, and the receiving device identifies the related frame based on the sequence number and transmits a plurality of frames. recognizing the transmission data that spans the transmission data, and if there is an error in the received transmission data, the data comparison and replacement unit 34 selects and synthesizes error-free frames from the transmission data to which the same sequence number is assigned, This is to generate normal transmission data corresponding to the sequence number, so that each transmission data can be clearly identified when receiving transmission data over multiple frames. Even if the leading frame is lost, the transmission data can be specified by the sequence number, and by requesting retransmission of the leading frame, the possibility of decoding the transmission data can be increased.

Advantageous Effects of Invention According to the present invention, when transmission data transmitted over a plurality of frames is transmitted a plurality of times, the receiving side can easily identify the same data and combine normal data. Suitable for wireless transmission systems that can improve the rate.

REFERENCE SIGNS LIST 1 command console 2 line control device 3 base station device 4 mobile station device 31 radio reception unit 32 error data detection unit 33 data decoding unit 34 data comparison and replacement unit 35 ... transmission processing section, 36 ... wireless transmission section 301, 401 ... FACCH

Claims (4)

A wireless transmission system that performs data transmission using wireless communication,
a transmission device that, when the transmission data to be transmitted spans a plurality of frames, includes a check code for checking an error in the data in the frame in each frame, and transmits the transmission data a plurality of times;
receiving the transmission data a plurality of times and, if there is an error in the transmission data, selecting error-free frames from the transmission data received a plurality of times by judging the check code, and combining the selected frames; and a receiving device that generates normal transmission data. The transmitting device assigns a sequence number to each frame in transmission data,
2. The wireless transmission system according to claim 1, wherein said receiver discriminates said sequence number and recognizes transmission data composed of related frames according to said sequence number. When the receiving device cannot generate normal transmission data even if error-free frames are selected, the receiving device requests the transmitting device to resend the frames that are insufficient for the generation,
The transmitting device retransmits the frame to the receiving device in response to a retransmission request for the frame;
3. The radio transmission system according to claim 1, wherein said receiving device generates normal transmission data using said retransmitted frame. The receiving device makes a retransmission request to the transmitting device for a frame with an error in the first received transmission data,
The transmitting device retransmits the frame to the receiving device a plurality of times in response to a retransmission request for the frame;
3. The radio transmission system according to claim 1, wherein said receiving device generates normal transmission data using said frames retransmitted a plurality of times.

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