JP6813858B2 - Wireless communication system, wireless communication terminal, collision detection method, program - Google Patents

Description

The present invention relates to a wireless communication system for detecting frame collisions, a wireless communication terminal, a collision detection method, and a program.

With the spread of wireless LAN, the amount of communication with limited frequency resources is increasing, and the possibility of mutual communication interfering with each other is increasing.

In order to suppress interference, IEEE802.11, which is one of the wireless LAN standards, uses an access control method of carrier sense multiple access with collision avoidance function (Carrier Sense Multiple Access with Collaboration: CSMA / CA). In this access control method, the terminal always performs carrier sensing of the channel before transmission, confirms that the channel is not used, and then starts transmission.

However, in the CSMA / CA method, for example, there are cases where random waiting times match and transmissions occur at the same time, or carrier sense fails as in the hidden terminal problem, and communication interference is completely avoided. It was difficult. Therefore, various techniques for suppressing interference with other communications are used.

For example, Patent Document 1 is known as a technique for suppressing such interference with other communications and improving data transmission efficiency. Patent Document 1 describes a data transmission / reception unit that wirelessly transmits a plurality of test packets, and a signal sensing unit that senses the power of a space radio signal on the same frequency channel as the test packet and outputs sample data of the space radio signal. A communication having a calculation processing unit that converts sample data into time-series sample data, and a collision detection unit that detects packet collisions due to interference between a plurality of test packets and other communications based on the time-series sample data. The device is described. According to Patent Document 1, parameters for transmitting data are adjusted based on the detection result of the collision detection unit.

Further, as a technique for suppressing communication interference, for example, there is a technique such as Patent Document 2. Patent Document 2 describes each slot based on a receiving means for receiving a packet, a packet detecting means for detecting in which slot the packet received by the receiving means is received, and a result detected by the packet detecting means. Describes a communication device having a frame information generation means for generating frame information indicating whether packet reception was successful or unsuccessful, and a transmission slot selection means for selecting a slot for transmitting a packet based on the frame information. ing. According to Patent Document 2, the transmission slot selection means changes the transmission slot of its own transmission slot when it fails continuously over a plurality of frames.

Japanese Unexamined Patent Publication No. 2013-005097 Japanese Unexamined Patent Publication No. 2007-028550

However, in the technique of Patent Document 1, when determining a packet collision, the power of the spatial radio signal is sensed, the sample data of the sensed spatial radio signal is converted into time-series sample data, and based on the time-series data. , A relatively complicated process of determining packet collision due to interference with other communication is required.

Further, the technique described in Patent Document 2 is a technique using a TDMA (Time Division Multiple Access) method. Therefore, it cannot be used in the CSMA / CA method, and it is necessary to perform various processes such as the need to synchronize the division time axis with the slots.

As described above, when communicating using the CSMA / CA method, for example, when trying to detect a collision of radio frame signals, there is a problem that the processing becomes complicated.

Therefore, an object of the present invention is to provide a wireless communication system that solves the problem that the processing becomes complicated when an attempt is made to detect a collision of a wireless frame signal.

A wireless communication system, which is an embodiment of the present invention, in order to achieve such an object
A packet division unit that divides the data to be transmitted into multiple parts,
A transmission device including a radio frame signal transmission unit that assigns an error detection code to each of the plurality of divided data divided by the packet division unit to generate one radio frame signal, and transmits the generated radio frame signal. When,
A wireless frame signal receiving unit that receives the wireless frame signal transmitted by the transmitting device and extracts the plurality of divided data from the received wireless frame signal.
It has a collision detection unit that detects a collision based on the extraction result of the radio frame signal, and a receiving device having the collision detection unit.
The wireless frame signal receiving unit of the receiving device takes out the plurality of divided data by using the error detection code assigned to each of the plurality of divided data.
The collision detection unit of the receiving device adopts a configuration in which a collision is detected based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code.

Further, the wireless communication terminal which is another form of the present invention is
A wireless frame signal receiving unit that receives a wireless frame signal generated by assigning an error detection code to each of the plurality of divided data and extracts the plurality of divided data from the received wireless frame signal.
It has a collision detection unit that detects a collision based on the extraction result of the radio frame signal, and
The wireless frame signal receiving unit takes out the plurality of divided data by using the error detection code assigned to each of the plurality of divided data.
The collision detection unit adopts a configuration in which a collision is detected based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code.

In addition, the collision detection method, which is another embodiment of the present invention,
A radio frame signal generated by assigning an error detection code to each of the plurality of divided data is received, and the error detection code assigned to each of the plurality of divided data is used from the received radio frame signal. Then, each of the plurality of divided data is taken out,
As a result of extracting the divided data using the error detection code, the collision is detected based on the position of the divided data that failed to be extracted.

In addition, the program which is another form of the present invention
For wireless communication terminals
A radio frame signal receiving means that receives a radio frame signal generated by assigning an error detection code to each of the plurality of divided data and extracts the plurality of divided data from the received radio frame signal.
A collision detecting means for detecting a collision based on the extraction result of the radio frame signal is realized.
The wireless frame signal receiving means takes out the plurality of divided data by using the error detection code assigned to each of the plurality of divided data.
The collision detecting means is a program that detects a collision based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code.

The present invention can provide a wireless communication system that solves the problem that the processing becomes complicated when an attempt is made to detect a collision by being configured as described above.

It is a block diagram which shows the structure of the communication apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the flow when the wireless communication part which concerns on 1st Embodiment of this invention generate a frame based on a packet. It is a figure which shows the flow when the wireless communication part which concerns on 1st Embodiment of this invention performs frame aggregation. It is a figure which shows an example when the packet division / coupling part which concerns on 1st Embodiment of this invention divides a packet. It is a figure which shows another example when the packet division / coupling part which concerns on 1st Embodiment of this invention divides a packet. It is a figure which shows the flow of frame aggregation when the tip part is divided into short parts. It is a figure which shows the flow at the time of taking out a packet when the tip part is divided into short parts. It is a flowchart which shows an example of the operation when the communication apparatus which concerns on 1st Embodiment of this invention transmits a wireless frame signal. It is a flowchart which shows an example of the operation when the communication apparatus which concerns on 1st Embodiment of this invention detects a collision. It is a flowchart which shows an example of another operation when the communication apparatus which concerns on 1st Embodiment of this invention detects a collision. It is a figure which shows another example when the packet division / coupling part divides a packet. It is a block diagram which shows the structure of the communication apparatus which concerns on 2nd Embodiment of this invention. It is a schematic block diagram which shows the structure of the wireless communication system which concerns on 3rd Embodiment of this invention. It is a schematic block diagram which shows the structure of the wireless communication apparatus which concerns on 4th Embodiment of this invention.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a communication device 1. FIG. 2 is a diagram showing a process when the wireless communication unit 12 generates a frame based on a packet. FIG. 3 is a diagram showing a process when the wireless communication unit 12 performs frame aggregation. FIG. 4 is a diagram showing an example when the packet dividing / combining unit 14 divides a packet. FIG. 5 is a diagram showing another example when the packet dividing / combining unit 14 divides a packet. FIG. 6 is a diagram showing a flow of frame aggregation when the tip portion is divided into short parts. FIG. 7 is a diagram showing a flow when taking out a packet when the tip portion is divided into short parts. FIG. 8 is a flowchart showing an example of an operation when the communication device 1 transmits a wireless frame signal. FIG. 9 is a flowchart showing an example of the operation when the communication device 1 detects a collision. FIG. 10 is a flowchart showing an example of another operation when the communication device 1 detects a collision. FIG. 11 is a diagram showing another example when the packet dividing / combining unit 14 divides a packet.

In the first embodiment of the present invention, a communication device 1 (transmitting device, receiving device, wireless communication terminal) for detecting a collision of wireless frame signals will be described. The communication device 1 in the present embodiment divides the data to be transmitted into a plurality of pieces, adds FCS (Frame Check Sequence) to each of the divided data, and then generates and transmits a radio frame signal. Further, when the communication device 1 extracts a plurality of divided data from the received wireless frame signal, the communication device 1 checks the FCS to determine whether or not the divided data has been successfully extracted. Then, the communication device 1 detects the collision based on whether or not the division data has been successfully fetched and the position of the split data that has failed to be fetched.

Referring to FIG. 1, the communication device 1 in the present embodiment includes an antenna 11, a wireless communication unit 12 (radio frame signal transmission unit, wireless frame signal reception unit), a collision detection unit 13, and a packet division / coupling unit 14. It has (packet dividing unit), a packet dividing / combining method determining unit 15, and a storage unit 16.

The functions of the above parts can be realized by an arithmetic unit such as a CPU (Central Processing Unit). That is, by preparing a semiconductor memory, a disk, or other recording medium in which a program for making the CPU function as each of the above-mentioned parts is recorded and causing the CPU to read the above-mentioned program, the CPU controls its own operation according to the read program and owns the CPU. Each of the above parts will be realized above.

The antenna 11 is connected to the wireless communication unit 12. The communication device 1 in the present embodiment transmits / receives a wireless frame signal to / from another communication device via the antenna 11.

In this embodiment, the case where the communication device 1 has one antenna 11 will be described. However, the number of antennas 11 included in the communication device 1 is not limited to one. The communication device 1 can be configured to have two or more antennas 11. At that time, the communication device 1 may be configured to use diversity technology or the like.

The wireless communication unit 12 converts the data (packet) to be transmitted into a radio wave signal (frame, wireless frame signal) and transmits the data (packet) via the antenna 11 by using a method compliant with IEEE802.11. Further, the wireless communication unit 12 converts the signal (frame, wireless frame signal) received from the antenna 11 into data (packet) and receives it. In this way, the communication device 1 uses the wireless communication unit 12 to exchange data with other communication devices.

FIG. 2 shows an example of the flow when the wireless communication unit 12 converts a packet into a frame. Referring to FIG. 2, the wireless communication unit 12 attaches a MAC (Media Access Control) header before the data packet to be transmitted (for example, data received from the upper layer in the communication device 1) and after the data packet. FCS (error detection code: data added to check if there is an error in the wireless frame) is attached to. Then, the wireless communication unit 12 attaches a PHY (Physical) header while performing modulation or the like, and converts the signal into a wireless frame signal.

Further, the wireless communication unit 12 in the present embodiment performs frame aggregation for transmitting a plurality of packets as one. Specifically, the wireless communication unit 12 in the present embodiment performs A-MPDU (Aggression MAC Protocol Data Unit) aggregation. A-MPDU aggregation is a technique for generating one radio frame signal by aggregating a plurality of MAC frames having a MAC header, data, and FCS.

For example, referring to FIG. 3, the wireless communication unit 12 attaches a MAC header and an FCS to each of the data to be aggregated (three in the case of FIG. 3, and may be other than three). After that, the wireless communication unit 12 attaches a header (delimiter) for indicating the frame delimiter before the frame to which the MAC header and the FCS are attached, and needs padding data for aligning the lengths behind the frame. Attach accordingly. Then, the wireless communication unit 12 combines the above frames into one frame, attaches a PHY (Physical) header while performing modulation, and converts the frame into a wireless frame signal.

In this way, the wireless communication unit 12 converts the packet into a wireless frame signal. Further, the wireless communication unit 12 aggregates a plurality of packets and converts them into one wireless frame signal. Then, the wireless communication unit 12 transmits the converted wireless frame signal.

The wireless communication unit 12 may be configured to measure the received signal strength (RSSI: Received Signal Strength Indicator), which indicates the strength of the received signal, when the wireless frame signal is received or the like. In addition, the wireless communication unit 12 can be configured to transmit a Block Ack frame indicating that the delivery has been confirmed, such as when receiving a Block Acc Req frame which is a frame requesting the confirmation of delivery.

The collision detection unit 13 determines from the received packet whether or not there is a wireless frame collision and what kind of collision has occurred. As will be described later, the collision detection unit 13 in the present embodiment determines the presence or absence of a wireless frame collision and what kind of collision has occurred, depending on the success or failure of packet retrieval and the position of the packet that failed to be retrieved. become.

Further, for example, when the wireless communication unit 12 is configured to measure RSSI, the collision detection unit 13 determines the presence or absence of a collision and what kind of collision has occurred in consideration of the measured RSSI. Can be done.

The collision detection unit 13 may be configured to determine whether or not to detect the collision and to detect the collision if necessary. Further, the collision detection unit 13 performs when determining the presence or absence of a collision according to how each packet generated based on the radio frame signal is divided (for example, the relationship of the packet length of each packet). It can be configured to change the processing method. The specific processing when the collision detection unit 13 determines whether or not there is a radio frame collision will be described later.

The packet division / combination unit 14 divides the packet into two or more and transmits the packet to the wireless communication unit 12 according to the instruction from the packet division / combination method determination unit 15. Further, the packet division / combination unit 14 combines the divided data frames (divided data) received from the wireless communication unit 12 and restores the data as one or more data.

For example, the packet division / combination unit 14 uses the number of division start bytes X stored in the storage unit 16 described later, and the number of bytes of the division data located at the front (for example, the tip) of the packet is larger than that of the division data. The packet is divided so that it is shorter than the number of bytes of the divided data located at the rear. Specifically, for example, as shown in FIG. 4, the packet division / combination unit 14 uses N bytes (N is an arbitrary number) of data of X bytes of data 1 (division data) and NX bytes of data. It is divided into two divided data, data 2 (divided data) and data 2. However, it is assumed that X <NX.

It is desirable that the X bytes are X <N, a sufficiently small number, and the number of bytes that do not require padding for the data. More preferably, X bytes is the minimum number of bytes that does not require padding on the data.

By setting the X-byte in this way, it is possible to detect a collision in a short time in the time axis direction. That is, in the communication method using CSMA / CA, when it is determined by carrier sensing that transmission is possible, transmission is performed after waiting a random time so that mutual transmissions do not collide. Therefore, if the random times coincide with each other by chance, they may communicate at the same time. In this case, the collision occurs in a form in which the head portions of the packets overlap. Therefore, by reducing the size of the packet at the beginning of the packet, it is possible to detect the collision in the case of simultaneous communication in a short time in the time axis direction. Moreover, the padding given to the data is meaningless data. Therefore, it is possible to reduce the waste of communication by using the data that is originally desired to be sent for the number of bytes that do not require padding.

Further, for example, the packet division / coupling unit 14 divides the packet into equal intervals (equal packet length) by using the number of division bytes Y stored in the storage unit 16 described later. Specifically, for example, as shown in FIG. 5, the packet division / coupling unit 14 divides N-byte data into m pieces with Y bytes. If N bytes are not divisible by Y bytes, only the last data m will be the remaining bytes of N / Y.

By dividing at equal intervals in this way, it is possible to adjust the number of divided bytes Y based on the situation where a collision is detected. For example, assume a situation in which a packet is divided into 10 packets according to the number of divided bytes Y, and as a result of detecting a collision, four consecutive collisions occur in the middle of the packet. In this case, if the number of divided bytes Y is doubled so that the packet is divided into five, two collisions will occur in succession. In this way, by adjusting the number of bytes Y according to the collision situation, the number of divisions when detecting a collision can be reduced. As a result, it is possible to reduce the data (delimiter, etc.) required for division other than the data originally desired to be transmitted. Further, contrary to the above, it is assumed that the collision of one packet is always detected as a result of detecting the collision. In this case, for example, by halving the number of bytes Y and dividing the packet into small pieces, it is possible to detect the collision situation faster and more accurately with respect to the time axis. Further, when retransmitting a frame in which a collision has occurred, the frame to be retransmitted can be shortened.

In this way, the number of divided bytes Y can be adjusted according to the situation of the collision that is occurring and the like. For example, the number of divided bytes Y can be adjusted according to the packet length that collides the most among the plurality of frames (the number of bytes of the divided data in which the most collisions are detected). Further, the number of divided bytes Y may be adjusted according to, for example, the least common multiple of a plurality of frames or the minimum interference frame (the smallest number of bytes among the detected collisions).

The packet division / combination unit 14 may be configured to divide the packet into three or more by using the division start byte number X. However, when the packet is divided, data different from the data originally desired to be transmitted, such as the delimiter and padding, is added as compared with the case where the packet is not divided. Therefore, it may be desirable that the number of divisions is small. Further, the packet division / combination unit 14 sets the packet so that the number of bytes of the divided data located at the rear (for example, the rear end) of the packet is shorter than the number of bytes of the divided data located before the divided data. You may divide it.

Further, the packet division / coupling unit 14 may be configured to divide by using the division number Z instead of the division byte number Y. In this case, for example, when the number of divisions Z = 10, the packet division / coupling unit 14 divides the N-byte packet into 10.

Further, in the present embodiment, it is assumed that the communication device 1 has a wireless communication unit 12 and a packet division / coupling unit 14. However, the packet division / coupling unit 14 may be realized in the wireless communication unit 12.

The packet division / combination method determination unit 15 determines how the packet division / combination unit 14 divides or combines data. The packet division / combination method determination unit 15 determines, for example, to divide the data using the number of division start bytes X stored in the storage unit 16. Further, the packet division / combination method determination unit 15 determines, for example, to divide the data at equal intervals using the number of division bytes Y stored in the storage unit 16.

Further, the packet division / combination method determination unit 15 adjusts the number of division start bytes X and the number of division bytes Y stored in the storage unit 16 according to the presence / absence of a collision detected by the collision detection unit 13 and the collision situation. Can be configured to do so.

In the present invention, the method used by the packet division / combination method determination unit 15 to determine the division method and the like is not particularly limited. The packet division / combination method determination unit 15 can determine how to divide the data by using an arbitrary method.

The storage unit 16 is composed of a semiconductor memory or the like.

The storage unit 16 can store the number of division start bytes X, the number of division bytes Y, the number of divisions Z, and the like used by the packet division / combination unit 14 and the packet division / integration method determination unit 15. Further, the storage unit 16 contains a determination standard used when the communication device 1 determines whether or not to determine a collision, and a received signal strength used when the collision detection unit 13 adds RSSI to detect a collision. It is possible to store a threshold value (for example, a value according to the strength of the received signal when the extraction is successful in the past. A plurality of threshold values can be stored according to the transmission rate of the received signal) and the like.

The storage unit 16 does not have to store all the above information. The storage unit 16 can store information required when the collision detection unit 13 and the packet division / coupling unit 14 perform processing, as needed.

The communication device 1 has, for example, the above configuration.

The communication device 1 may be configured to determine whether or not to detect a collision. When determining whether or not to detect a collision, the communication device 1 determines whether or not to detect a collision according to, for example, a determination criterion stored in the storage unit 16. Specifically, for example, it is determined that the communication device 1 does not detect a collision for a Beacon frame, but detects a collision for a data frame. Further, for example, the communication device 1 can be configured to determine whether or not to detect a collision for each type of wireless LAN frame, or to always detect a collision.

Further, when the communication device 1 determines that the collision is not detected, the communication device 1 transmits the packet as a wireless frame signal by the wireless communication unit 12 as usual without performing the packet division processing by the packet division / coupling unit 14. Can be configured as follows.

Next, the radio frame signal transmission process and the collision detection process performed by using the communication device 1 will be described in more detail. First, as an example of the processing performed by the communication device 1, when the packet division / coupling unit 14 divides N-byte data into X-byte data 1 and NX-byte data 2 and transmits a wireless frame signal. An example of processing will be described in detail.

In this case, as shown in FIG. 6, the packet division / combination unit 14 converts N-byte data into X-byte data 1 and NX-byte data in response to an instruction from the packet division / combination method determination unit 15. Divide into two.

Subsequently, the wireless communication unit 12 attaches a MAC header and an FCS to each of the data 1 and the data 2 divided by the packet division / coupling unit 14. After that, the wireless communication unit 12 attaches a header (delimiter) for indicating the frame delimiter before the frame to which the MAC header and the FCS are attached, and needs padding data for aligning the lengths behind the frame. Attach accordingly. Then, the wireless communication unit 12 combines the above frames into one frame, attaches a PHY (Physical) header while performing modulation, and converts the frame into a wireless frame signal. After that, the wireless communication unit 12 will transmit the converted wireless frame signal.

In this way, the communication device 1 divides the data to be transmitted into data 1 and data 2, adds FCS to each of the divided data, and then generates and transmits a wireless frame signal.

Subsequently, a process when the communication device 1 that has received the radio frame signal transmitted as described above detects a collision will be described.

In this case, as shown in FIG. 7, the wireless communication unit 12 receives the wireless frame signal while performing demodulation or the like with reference to the PHY header or the like. After that, the wireless communication unit 12 divides the frames with reference to the delimiter, and extracts data 1 and data 2 from each frame. In this way, the wireless communication unit 12 extracts the packet by the method specified in IEEE802.11. Here, if no collision has occurred, no error is detected in the data 1 and the data 2 even if the FCS is checked. Therefore, the wireless communication unit 12 can normally take out the data 1 and the data 2. On the other hand, when an error is detected as a result of checking the FCS, the wireless communication unit 12 cannot normally retrieve the data.

In this way, the wireless communication unit 12 extracts data 1 and data 2 from the received wireless frame signal. Further, the wireless communication unit 12 determines whether or not the data 1 and the data 2 can be taken out normally by using the FCS assigned to each of the data 1 and the data 2.

The collision detection unit 13 determines whether or not there is a wireless frame collision and what kind of collision there is based on whether or not the wireless communication unit 12 has normally extracted the data 1 and 2 and the position of the data that failed to be extracted. Determine if has occurred.

Specifically, the collision detection unit 13 determines that no collision has occurred when both the data 1 and the data 2 are successfully retrieved.

Further, the collision detection unit 13 detects a collision that occurs from the start of transmission of the radio frame signal when the data 1 fails to be fetched and the data 2 can be fetched normally. That is, the collision detection unit 13 detects a collision that occurs from the start of transmission of the radio frame signal when the divided data located at the front end fails and the divided data located at the rear end is successfully taken out.

On the other hand, the collision detection unit 13 determines that, for example, the collision situation is unknown when the data 1 and the data 2 are unsuccessfully retrieved, or when the data 1 is successfully fetched but the data 2 is unsuccessful.

The collision detection unit 13 performs collision detection processing by, for example, the above processing.

In the above description, the case where the packet is divided into two, data 1 and data 2, has been described. However, the above processing is not limited to the case where the packet is divided into two, and can be performed. By performing the same processing, the collision detection unit 13 can detect a collision even when the radio frame signal generated by dividing the packet into three or more is received.

Further, in the above description, if the collision detection unit 13 succeeds in extracting the data 1 but fails in extracting the data 2, it is determined that the collision situation is unknown. However, if the collision detection unit 13 succeeds in extracting the data 1 and fails in extracting the data 2, the collision detection unit 13 may be configured to detect a collision generated during the transmission of the radio frame signal.

Further, the collision detection unit 13 can be configured to take RSSI into consideration when detecting a collision. For example, the collision detection unit 13 can use RSSI when the extraction of the data 1 and the data 2 fails. Specifically, for example, the collision detection unit 13 compares the received RSSI with the reception signal strength threshold value stored in the storage unit 16. As a result, the collision detection unit 13 can determine whether the signal did not reach due to attenuation or the like, or whether the collision occurred over both the data 1 and the data 2.

In this case, for example, the collision detection unit 13 determines that a collision has occurred in the entire data 1 and data 2 when the RSSI is equal to or higher than the received signal strength threshold value. On the other hand, the collision detection unit 13 determines that the collision situation is unknown (the signal is attenuated) when the RSSI is smaller than the received signal strength threshold value.

Further, the wireless communication unit 12 can be configured to notify the transmission side of the delivery status when the collision detection unit 13 detects a collision. This notification may be performed using, for example, the Block Ack Bitmap field in the Block Ack frame. Specifically, for example, the value of the corresponding bit position is set to 1 indicating that the bit position was normally received when the extraction is successful. On the other hand, if the retrieval fails, it is set to 0, which indicates that an error has occurred. The wireless communication unit 12 notifies the transmitting side of the collision detection status by using, for example, the Block Ac frame set as described above.

Further, the communication device 1 on the transmitting side that has received the above notification can detect the collision of the radio frame signal transmitted by itself by the notification. Further, it is conceivable that the communication device 1 on the transmitting side transmits a retransmitted packet. At this time, the retransmitting communication device 1 can be configured to insert the retransmitted packet at a position where the previous retrieval has not failed.

Next, an example of processing when the packet division / coupling unit 14 divides N-byte data into m pieces by Y bytes and transmits a wireless frame signal will be described in detail.

In this case, the packet division / combination unit 14 divides the N-byte data into m Y-byte data according to the instruction from the packet division / combination method determination unit 15.

Subsequently, the wireless communication unit 12 attaches a MAC header and an FCS to each of the m divided data divided by the packet dividing / combining unit 14. After that, the wireless communication unit 12 attaches a header (delimiter) for indicating the frame delimiter before the frame to which the MAC header and the FCS are attached, and needs padding data for aligning the lengths behind the frame. Attach accordingly. Then, the wireless communication unit 12 combines the above frames into one frame, attaches a PHY (Physical) header while performing modulation, and converts the frame into a wireless frame signal. After that, the wireless communication unit 12 will transmit the converted wireless frame signal.

As described above, the communication device 1 in the present embodiment divides the data to be transmitted into a plurality of data by the same processing as when the number of divided start bytes X is used, and after adding FCS to each of the divided data, Generates and transmits a wireless frame signal.

Subsequently, a process when the communication device 1 that has received the radio frame signal transmitted as described above detects a collision will be described.

In this case as well, as in the case of using the division start byte number X, the wireless communication unit 12 receives the wireless frame signal while performing demodulation or the like with reference to the PHY header or the like. After that, the wireless communication unit 12 divides the frames with reference to the delimiter, and extracts m divided data from the frames. Further, at this time, the wireless communication unit 12 checks the FCS and determines whether or not each divided data can be taken out normally.

The collision detection unit 13 determines whether or not there is a radio frame collision and what kind of collision has occurred based on whether or not each of the m divided data can be normally extracted and the position of the data that failed to be extracted. To judge.

Specifically, when the collision detection unit 13 succeeds in extracting all the divided data, it determines that no collision has occurred.

Further, when the collision detection unit 13 fails to take out the divided data at the front end and succeeds in taking out the divided data at the rear end, the collision detection unit 13 detects a collision that occurs from the start of transmission of the radio frame signal.

Further, when the collision detection unit 13 fails to take out the divided data at the front end and fails to take out the divided data at the rear end, the collision detection unit 13 compares RSSI with the received signal strength threshold value. Then, the collision detection unit 13 determines that a collision has occurred as a whole when the RSSI is equal to or higher than the received signal strength threshold value. On the other hand, the collision detection unit 13 determines that the collision situation is unknown (the signal is attenuated) when the RSSI is smaller than the received signal intensity threshold value.

Further, when the collision detection unit 13 succeeds in extracting the divided data at the tip and fails to extract the divided data at any position other than the tip, the collision detection unit 13 detects a collision generated during the transmission of the radio frame signal. .. On the other hand, the collision detection unit 13 determines that the collision situation is unknown when the split data at the tip is successfully fetched and there is no split data in the middle that fails to be fetched.

The collision detection unit 13 performs collision detection processing by, for example, the above processing. By such processing, it is possible to detect the presence or absence of "collision that occurs from the start of transmission of the wireless frame signal", "collision that occurs as a whole", and "collision that occurs during the transmission of the wireless frame signal".

If the collision detection unit 13 fails to retrieve the split data at the tip and fails to retrieve the split data at the rear end, the collision detection unit 13 determines that the collision status is unknown without comparing the RSSI with the received signal strength threshold value. It doesn't matter.

Further, when the collision detection unit 13 detects a collision, the wireless communication unit 12 may be used to notify the transmitting side of the delivery status. Further, it is conceivable that the communication device 1 on the transmitting side that has received the above notification transmits a retransmitted packet. At this time, the retransmitting communication device 1 may be configured to insert the retransmitted packet at a position where the previous retrieval has not failed.

Next, the operation of the communication device 1 will be described with reference to the flowcharts of FIGS. 8 to 10.

First, the operation when the communication device 1 transmits the wireless frame signal will be described with reference to FIG.

With reference to FIG. 8, the communication device 1 determines whether or not to perform a collision determination (step S101). The communication device 1 determines, for example, that the Beacon frame does not perform collision determination, while the data frame performs collision determination.

Then, when it is determined that the collision determination is not performed (step S101, No), the communication device 1 converts the packet into a wireless frame signal by the wireless communication unit 12 and transmits the packet as usual (step S104).

On the other hand, when it is determined that the collision determination is to be performed (step S101, Yes), the packet division / combination method determination unit 15 determines how to divide the data (step S102).

For example, the packet division / combination method determination unit 15 determines to divide the data using the division start byte number X stored in the storage unit 16. Further, for example, the packet division / combination method determination unit 15 determines to divide the data at equal intervals using the number of division bytes Y stored in the storage unit 16.

Then, the packet division / combination method determination unit 15 instructs the packet division / combination unit 14 of the determined method.

Subsequently, the packet division / combination unit 14 divides the packet according to the instruction of the packet division / combination method determination unit 15 (step S103).

For example, the packet division / combination unit 14 divides N-byte data into two divided data, X-byte data 1 and NX-byte data 2. Further, for example, the packet division / coupling unit 14 divides N-byte data into m pieces by Y bytes.

After that, the wireless communication unit 12 performs frame aggregation, aggregates the divided plurality of packets while adding FCS to each of them, and converts them into one wireless frame signal. Then, the wireless communication unit 12 transmits the converted wireless frame signal (step S104).

The above is the operation when the communication device 1 transmits the wireless frame signal. Next, the operation when the communication device 1 receives the wireless frame signal and detects a collision occurring from the start of transmission of the wireless frame signal will be described. In this operation, for example, the radio frame signal divided so that the number of bytes of the divided data located at the front (for example, the tip) of the packet is shorter than the number of bytes of the divided data located after the divided data. It is performed when it is received.

Referring to FIG. 9, the wireless communication unit 12 receives the wireless frame signal received via the antenna 11 while performing demodulation or the like with reference to the PHY header or the like.

Next, the wireless communication unit 12 performs an extraction process of the aggregated packet (step S201). That is, the wireless communication unit 12 performs a process of extracting a plurality of divided data from the received wireless frame signal.

Subsequently, the collision detection unit 13 determines whether or not to detect the collision (step S202).

Then, when the collision detection unit 13 determines that the collision is not detected (step S202, No), the state of the collision is unknown (step S207), and the process ends.

On the other hand, when the collision detection unit 13 determines that the collision is detected (step S202, Yes), the collision detection unit 13 determines whether or not all the divided data included in the radio frame signal has been successfully extracted (step). S203).

Then, when the collision detection unit 13 succeeds in extracting all the divided data (step S203, Yes), the collision detection unit 13 determines that no collision has occurred (step S205) and ends the process.

On the other hand, if there is divided data that the collision detection unit 13 has failed to retrieve (steps S203, No), whether or not the fetching of the split data at the tip has failed and the split data at the rear end has been successfully fetched. Determine (step S204).

Then, when the collision detection unit 13 fails to take out the divided data at the front end and succeeds in taking out the divided data at the rear end (step S204, Yes), the collision detection unit 13 is generated from the start of transmission of the radio frame signal. The collision is detected (step S206) and the process ends.

On the other hand, when the collision detection unit 13 fails to take out the divided data at the front end and fails to take out the divided data at the rear end (step S204, No), the collision detection unit 13 determines that the collision situation is unknown (step). S207) to end the process.

The above is an example of the operation when the communication device 1 receives the wireless frame signal and detects a collision occurring from the start of transmission of the wireless frame signal. Next, when the communication device 1 receives the wireless frame signal, the "collision that occurs from the start of transmission of the wireless frame signal", the "collision that occurs as a whole", and the "collision that occurs during the transmission of the wireless frame signal" The operation when detecting the presence / absence will be described. This operation is performed, for example, when the divided data receives a radio frame signal divided at equal intervals.

Referring to FIG. 10, the wireless communication unit 12 receives the wireless frame signal received via the antenna 11 while performing demodulation or the like with reference to the PHY header or the like.

Next, the wireless communication unit 12 performs an extraction process of the aggregated packet (step S301). That is, the wireless communication unit 12 performs a process of extracting a plurality of divided data from the received wireless frame signal.

Subsequently, the collision detection unit 13 determines whether or not to detect the collision (step S302).

When the collision detection unit 13 determines that the collision is not detected (step 3202, No), the state of the collision is unknown (step S312), and the process ends.

On the other hand, when the collision detection unit 13 determines that the collision is detected (step S302, Yes), the collision detection unit 13 determines whether or not all the divided data included in the radio frame signal has been successfully extracted (step). S303).

Then, when the collision detection unit 13 succeeds in extracting all the divided data (step S303, Yes), the collision detection unit 13 determines that no collision has occurred (step S308) and ends the process.

On the other hand, when there is divided data for which extraction has failed (step S303, No), the collision detection unit 13 determines whether or not the divided data at the tip has been successfully extracted (step S304).

Then, when the extraction of the divided data at the tip is successful (step S304, Yes), it is determined whether or not the extraction of the divided data at any position other than the tip has failed (step S305). Then, when the extraction of the divided data at any position other than the tip has failed (step S305, Yes), the collision detection unit 13 detects the collision generated during the transmission of the wireless frame signal (step S311). And end the process. On the other hand, when there is no divided data in the middle that failed to be fetched (step S305, No), the collision detection unit 13 determines that the collision status is unknown (step S312), and ends the process.

Further, when the extraction of the split data at the tip has failed (step S304, No), the collision detection unit 13 determines whether or not the retrieval of the split data at the rear end has succeeded (step S306). Then, when the extraction of the rear end divided data is successful (step S306, Yes), the collision detection unit 13 detects the collision generated from the start of transmission of the wireless frame signal (step S309) and ends the process. To do.

On the other hand, when the extraction of the divided data at the rear end has failed (step S306, No), the collision detection unit 13 compares RSSI with the received signal intensity threshold value (step S307). Then, when RSSI is equal to or higher than the received signal strength threshold value (step S307, Yes), the collision detection unit 13 determines that a collision has occurred as a whole (step S310) and ends the process. On the other hand, when RSSI is smaller than the received signal strength threshold value (step S307, No), the collision detection unit 13 determines that the collision status is unknown (step S312), and ends the process.

The above is the above, when the communication device 1 receives the wireless frame signal, "collision that occurs from the start of transmission of the wireless frame signal", "collision that occurs as a whole", and "collision that occurs during the transmission of the wireless frame signal". This is an example of an operation when detecting the presence or absence.

As described above, the communication device 1 in the present embodiment has the packet division / coupling unit 14. Further, the wireless communication unit 12 is configured to be able to perform A-MPDU aggregation. With such a configuration, the communication device 1 can divide the data to be transmitted into a plurality of pieces, add FCS to each divided data, and then generate and transmit a wireless frame signal. As a result, the communication device 1 that has received the radio frame signal can detect a collision without performing complicated processing.

Further, the communication device 1 has a wireless communication unit 12 and a collision detection unit 13. With such a configuration, the communication device 1 can determine whether or not each divided data can be normally taken out by using the FCS added to each divided data based on the received wireless frame signal. .. As a result, the collision detection unit 13 determines whether or not there is a wireless frame collision and what kind of data is based on whether or not the wireless communication unit 12 has normally extracted each divided data and the position of the data that failed to be extracted. It is possible to determine whether a collision has occurred. In this way, the communication device 1 can detect a collision without performing complicated processing. That is, by having the above configuration, the communication device 1 can detect a collision without performing complicated processing.

The method used by the packet dividing / combining unit 14 to divide the packet is not limited to the case described above. For example, as shown in FIG. 11, the packet dividing / combining unit 14 can divide a packet by using the dividing bytes X1 and Y1 stored in the storage unit 16. Specifically, for example, as shown in FIG. 11, the packet splitting / combining unit 14 uses X1 byte data 1, N-X1-Y1 byte data 2, and Y1 byte data 3 for N-byte data. It can be divided into three divided data. It is desirable that the X1 byte and the Y1 byte are X1 <N-Y1, Y1 <N-X1, a sufficiently small number, and a number of bytes that do not require padding.

Further, by using the communication device 1 described in the present embodiment as a transmission device and a reception device, it is possible to realize a wireless communication system capable of detecting a collision by a simple method.

Further, in the present embodiment, the communication device 1 detects the collision based on whether or not the divided data is successfully fetched and the position of the split data that failed to be fetched. However, for example, the communication device 1 may be configured to detect a collision based on whether or not the divided data is successfully retrieved. Further, the communication device 1 may be configured to detect a collision based on the position of the divided data that failed to be fetched.

[Second Embodiment]
In the second embodiment of the present invention, the communication device 2 for detecting the collision of the radio frame signal will be described. The communication device 2 in the present embodiment performs the same processing as the communication device 1 described in the first embodiment to detect a collision. Further, the communication device 2 in the present embodiment is configured to redundantly transmit data at a position where a collision is likely to occur by using the redundant packet generation / removal unit 21 described later. ..

Referring to FIG. 12, the communication device 2 in the present embodiment has substantially the same configuration as the communication device 1 described in the first embodiment. That is, the communication device 2 includes an antenna 11, a wireless communication unit 12, a collision detection unit 13, a packet division / combination unit 14, a packet division / combination method determination unit 15, and a storage unit 16. There is. Further, the communication device 2 in the present embodiment has a redundant packet generation / removal unit 21.

As described above, the communication device 2 in the present embodiment has substantially the same configuration as the communication device 1 described in the first embodiment. In this embodiment, the description of the content that overlaps with the description of the first embodiment will be omitted. Therefore, in the following, a configuration characteristic of the present embodiment will be described.

The collision detection unit 13 in the present embodiment detects the collision and predicts the position of the divided data (packet) in which the collision frequently occurs.

For example, when the collision is detected, the collision detection unit 13 stores the position of the divided data in which the collision is detected in the storage unit 16. Then, the collision detection unit 13 predicts the position of the divided data in which the collision frequently occurs, based on the position of the divided data in which the collision detected in the storage unit 16 is detected. Specifically, for example, when the collision detection unit 13 detects a collision equal to or higher than a predetermined threshold value within a predetermined time (or the number of times a radio frame signal is received or the number of times a collision is detected), the collision detection unit 13 concerned. It is determined that collisions frequently occur at the positions of the divided data.

The redundant packet generation / removal unit 21 makes the divided data at positions where collisions frequently occur redundant. For example, suppose that the collision detection unit 13 predicts that collisions will occur frequently based on the divided data at the tip of the packet. In this case, the redundant packet generation / removal unit 21 copies the divided data of the tip portion where the collision frequently occurs. Then, the redundant packet generation / removal unit 21 adds the copied content to another position (for example, the rearmost end) to make it redundant. Similarly, for example, suppose that the collision detection unit 13 predicts that collisions will occur frequently in the divided data in the middle of the packet. In this case, the redundant packet generation / removal unit 21 copies the divided data of the intermediate portion where the collision frequently occurs. Then, the redundant packet generation / removal unit 21 adds the copied contents to another position (for example, a position as far as possible from the position where the collision occurred, such as the rearmost end) to make it redundant.

In this way, the redundant packet generation / removal unit 21 makes the divided data at the position where the collision is expected to occur redundant.

Further, the redundant packet generation / removal unit 21 removes the redundant portion by, for example, the following processing. For example, the redundant packet generation / removal unit 21 stores the entire received plurality of divided data, checksums, hash values, and the like in the storage unit 16. Then, the redundant packet generation / removal unit 21 compares the extracted divided data with the entire divided data stored in the storage unit 16, a checksum, a hash value, or the like. As a result, the redundant packet generation / removal unit 21 determines whether or not the extracted divided data is the same as the past one. Then, when the extracted divided data corresponds to the redundant portion, the redundant packet generation / removal unit 21 discards the redundant portion, for example.

As described above, the communication device 2 in the present embodiment has a collision detection unit 13 for predicting the position of divided data in which collisions frequently occur, and a redundant packet generation / removal unit 21. With such a configuration, the redundant packet generation / removal unit 21 can make the divided data at the position where collisions frequently occur redundant. As a result, it is possible to eliminate the need for retransmission even when a collision occurs at the relevant location.

[Third Embodiment]
In the third embodiment of the present invention, the wireless communication system 5 for detecting the collision of wireless frame signals will be described. In this embodiment, the outline of the configuration of the wireless communication system 5 will be described.

Referring to FIG. 13, the wireless communication system 5 according to the present embodiment has a transmitting device 3 and a receiving device 4.

The transmission device 3 has a packet division unit 31 and a wireless frame signal transmission unit 32.

The packet division unit 31 divides the data to be transmitted into a plurality of pieces. Further, the wireless frame signal transmission unit 32 generates one wireless frame signal by assigning an error detection code to each of the plurality of divided data divided by the packet division unit 31. Then, the radio frame signal transmission unit 32 transmits the generated radio frame signal.

The receiving device 4 has a radio frame signal receiving unit 41 and a collision detecting unit 42.

The wireless frame signal receiving unit 41 receives the wireless frame signal transmitted by the wireless frame signal transmitting unit 32 of the transmitting device 3. Then, the radio frame signal receiving unit 41 extracts each of the plurality of divided data from the received radio frame signal by using the error detection code assigned to each of the plurality of divided data.

The collision detection unit 42 detects a collision based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code by the wireless frame signal receiving unit 41.

As described above, the transmission device 3 in the present embodiment has the packet division unit 31. With such a configuration, the communication device 3 can divide the data to be transmitted into a plurality of pieces, add an error detection code to each of the divided data, and then generate and transmit a wireless frame signal. As a result, the receiving device 4 that has received the radio frame signal can detect the collision without performing complicated processing.

Further, the receiving device 4 has a wireless frame signal receiving unit 41 that extracts divided data from the received wireless frame signal using an error detection code, and a collision detecting unit 42. With such a configuration, the collision detection unit 42 can detect a collision based on the position of the divided data that failed to be retrieved. As a result, it becomes possible to detect a collision without performing complicated processing.

Further, the wireless communication method executed by the wireless communication system 5 described above divides the data to be transmitted into a plurality of pieces, assigns an error detection code to each of the divided pieces of data, and generates one wireless frame signal. , The generated wireless frame signal is transmitted, the transmitted wireless frame signal is received, and a plurality of divided data are obtained from the received wireless frame signal by using the error detection code assigned to each of the plurality of divided data. It is a method of extracting each of them and detecting the collision based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code.

Even the invention of the wireless communication method having the above-described configuration can achieve the above-mentioned object of the present invention because it has the same operation as the above-mentioned wireless communication system 5.

[Fourth Embodiment]
In the fourth embodiment of the present invention, the wireless communication terminal 6 for detecting the collision of the received wireless frame signal will be described. In this embodiment, the outline of the configuration of the wireless communication terminal 6 will be described.

Referring to FIG. 14, the wireless communication terminal 6 has a wireless frame signal receiving unit 61 and a collision detecting unit 62.

The wireless frame signal receiving unit 61 receives the wireless frame signal generated by assigning an error detection code to each of the plurality of divided data. Then, the wireless frame signal receiving unit 61 extracts a plurality of divided data from the received wireless frame signal by using the error detection code assigned to each of the plurality of divided data.

The collision detection unit 62 detects a collision based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code by the wireless frame signal receiving unit 61.

As described above, the wireless communication terminal 6 in the present embodiment has a wireless frame signal receiving unit 61 for extracting divided data from the received wireless frame signal using an error detection code, and a collision detecting unit 62. With such a configuration, the collision detection unit 62 can detect a collision based on the position of the divided data that failed to be retrieved. As a result, it becomes possible to detect a collision without performing complicated processing.

Further, the wireless communication terminal 6 described above can be realized by incorporating a predetermined program into the wireless communication terminal 6. Specifically, the program according to another embodiment of the present invention receives the radio frame signal generated by assigning an error detection code to each of the plurality of divided data divided into the wireless communication terminal, and receives the received radio. The wireless frame signal receiving means 62 for extracting a plurality of divided data from the frame signal and the collision detecting means 61 for detecting a collision based on the extraction result of the wireless frame signal are realized, and the wireless frame signal receiving means 62 has a plurality of wireless frame signal receiving means 62. A plurality of divided data are extracted using the error detection code assigned to each of the divided data, and the collision detection means 61 retrieves the divided data using the error detection code, and as a result, the position of the divided data that failed to be extracted. It is a program to realize that collision is detected based on.

Further, the wireless communication method executed by operating the wireless communication terminal 6 described above receives a wireless frame signal generated by assigning an error detection code to each of the plurality of divided data, and receives the received. A plurality of divided data are extracted from the wireless frame signal using the error detection codes assigned to each of the plurality of divided data, and as a result of extracting the divided data using the error detection code, the divided data that failed to be extracted It is a method of detecting a collision based on the position.

Even the invention of the program or the wireless communication method having the above-mentioned configuration can achieve the above-mentioned object of the present invention because it has the same operation as the above-mentioned wireless communication terminal 6.

<Additional notes>
Part or all of the above embodiments may also be described as in the appendix below. Hereinafter, the outline of the wireless communication system and the like in the present invention will be described. However, the present invention is not limited to the following configurations.

(Appendix 1)
A packet division unit that divides the data to be transmitted into multiple parts,
A transmission device including a wireless frame signal transmission unit that assigns an error detection code to each of the plurality of divided data divided by the packet division unit to generate one wireless frame signal, and transmits the generated wireless frame signal. When,
A wireless frame signal receiving unit that receives the wireless frame signal transmitted by the transmitting device and extracts the plurality of divided data from the received wireless frame signal.
It has a collision detection unit that detects a collision based on the extraction result of the radio frame signal, and a receiving device having the collision detection unit.
The wireless frame signal receiving unit of the receiving device takes out the plurality of divided data by using the error detection code assigned to each of the plurality of divided data.
The collision detection unit of the receiving device is a wireless communication system that detects a collision based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code.

(Appendix 2)
The wireless communication system according to Appendix 1.
The radio frame signal receiving unit is configured to measure the strength of the received radio frame signal.
The collision detection unit is a wireless communication system that detects a collision based on the position of the divided data that failed to be retrieved and the strength of the received wireless frame signal.

(Appendix 3)
The wireless communication system according to Appendix 1 or 2.
When the collision detection unit fails to extract the divided data located at the front end of the plurality of divided data and succeeds in extracting the divided data located at the rear end, the transmission device transmits the wireless frame signal. A wireless communication system that detects collisions that have occurred since the start.

(Appendix 4)
The wireless communication system according to any one of Supplementary notes 1 to 3.
When the collision detection unit succeeds in extracting the divided data located at the tip of the plurality of divided data and fails to extract the divided data at any position other than the tip, the wireless frame by the transmitting device. A wireless communication system that detects collisions that occur during signal transmission.

(Appendix 4-1)
The wireless communication system according to any one of Appendix 1 to 4.
The radio frame signal receiving unit is configured to measure the strength of the received radio frame signal.
The collision detection unit fails to retrieve the data located at the front end of the plurality of data, fails to retrieve the data located at the rear end, and the strength of the radio frame signal is predetermined. A wireless communication system that detects a collision that occurs throughout the transmission of a wireless frame signal by the transmitting device when it is higher than the threshold value.

(Appendix 5)
The wireless communication system according to any one of Appendix 1 to 4.
The packet division unit divides the data to be transmitted so that the number of bytes of the divided data located at the tip of the plurality of divided data is shorter than the number of bytes of the divided data located behind the divided data. Communications system.

(Appendix 5-1)
The wireless communication system according to Appendix 5,
The packet division unit is a wireless communication system that divides the data to be transmitted so that the number of bytes of the divided data located at the tip thereof is the minimum number of bytes that do not require padding for the divided data.

(Appendix 6)
The wireless communication system according to any one of Appendix 1 to 4.
The packet division unit is a wireless communication system that divides the data to be transmitted at equal intervals based on predetermined parameters.

(Appendix 6-1)
The wireless communication system according to any one of Appendix 1 to 4.
The packet division unit divides the data to be transmitted so that the number of bytes of the predetermined divided data located behind the plurality of divided data is shorter than the number of bytes of the divided data located ahead of the divided data. Wireless communication system.

(Appendix 7)
The receiving device has a notification means for notifying the transmitting device that the collision detecting unit has detected a collision.
The transmitting device is a wireless communication system that redundantly transmits divided data at a position where a collision has occurred when notified by the receiving device that a collision has occurred.

(Appendix 7-1)
The wireless communication system according to Appendix 7,
The receiving device is a wireless communication system that uses a BlockAck frame to notify the transmitting device that a collision has occurred.

(Appendix 7-2)
The wireless communication system according to Appendix 7 or 7-1.
The transmitting device copies the divided data at the position where the collision occurred, and inserts the copied divided data at the position farthest from the position where the collision occurred among the divided data to be transmitted, thereby making the wireless communication system redundant. ..

(Appendix 7-3)
The wireless communication system according to any one of Appendix 1 to 7-2.
The transmitting device is a wireless communication system that predicts a position where a collision occurs and redundantly divides data of the predicted position where a collision occurs.

(Appendix 7-4)
The data to be transmitted is divided into a plurality of pieces, an error detection code is assigned to each of the divided pieces of data to generate one radio frame signal, and the generated radio frame signal is transmitted.
The transmitted wireless frame signal is received, and a plurality of divided data are extracted from the received wireless frame signal using the error detection code assigned to each of the plurality of divided data, and the divided data using the error detection code is used. Detects collisions based on the location of the split data that failed to be retrieved as a result of retrieval
Wireless communication method.

(Appendix 8)
A wireless frame signal receiving unit that receives a wireless frame signal generated by assigning an error detection code to each of the plurality of divided data and extracts the plurality of divided data from the received wireless frame signal.
It has a collision detection unit that detects a collision based on the extraction result of the radio frame signal, and
The wireless frame signal receiving unit takes out the plurality of divided data by using the error detection code assigned to each of the plurality of divided data.
The collision detection unit is a wireless communication terminal that detects a collision based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code.

(Appendix 8-1)
The wireless communication terminal described in Appendix 8
The radio frame signal receiving unit is configured to measure the strength of the received radio frame signal.
The collision detection unit is a wireless communication terminal that detects a collision based on the position of the divided data that failed to be retrieved and the strength of the received wireless frame signal.

(Appendix 8-2)
The wireless communication terminal according to Appendix 8 or 8-1.
When the collision detection unit fails to extract the divided data located at the tip of the plurality of divided data and succeeds in extracting the divided data located at the rear end, the collision detection unit is generated from the start of transmission of the radio frame signal. A wireless communication terminal that detects a collision.

(Appendix 9)
A radio frame signal generated by assigning an error detection code to each of the plurality of divided data is received, and the error detection code assigned to each of the plurality of divided data is used from the received radio frame signal. Then, each of the plurality of divided data is taken out,
A collision detection method that detects a collision based on the position of the divided data that failed to be extracted as a result of extracting the divided data using an error detection code.

(Appendix 9-1)
The collision detection method according to Appendix 9, wherein
While receiving the wireless frame signal, the strength of the received wireless frame signal is measured.
A collision detection method for detecting a collision based on the position of the divided data that failed to be retrieved and the strength of the received radio frame signal.

(Appendix 9-2)
The collision detection method according to Appendix 9 or 9-1.
When the extraction of the divided data located at the front end of the plurality of divided data fails and the extraction of the divided data located at the rear end is successful, a collision that occurs from the start of transmission of the wireless frame signal is detected. Detection method.

(Appendix 10)
For wireless communication terminals
A radio frame signal receiving means that receives a radio frame signal generated by assigning an error detection code to each of the plurality of divided data and extracts the plurality of divided data from the received radio frame signal.
A collision detecting means for detecting a collision based on the extraction result of the radio frame signal is realized.
The wireless frame signal receiving means takes out the plurality of divided data by using the error detection code assigned to each of the plurality of divided data.
The collision detecting means is a program that detects a collision based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code.

(Appendix 10-1)
The program described in Appendix 10
The wireless frame signal receiving means measures the strength of the received wireless frame signal and measures the strength of the received wireless frame signal.
The collision detecting means is a program that detects a collision based on the position of the divided data that failed to be retrieved and the strength of the received radio frame signal.

(Appendix 10-2)
The program according to Appendix 10 or 10-1.
When the collision detecting means fails to extract the divided data located at the front end of the plurality of divided data and succeeds in extracting the divided data located at the rear end, the collision detection means is generated from the start of transmission of the radio frame signal. A program that detects collisions.

(Appendix 11)
A packet division unit that divides the data to be transmitted into multiple parts,
Radio transmission including a radio frame signal transmission unit that assigns an error detection code to each of the plurality of divided data divided by the packet division unit to generate one radio frame signal and transmits the generated radio frame signal. apparatus.

(Appendix 12)
For wireless transmitters
A packet dividing means that divides the data to be transmitted into multiple parts,
A wireless frame signal transmitting means that assigns an error detection code to each of the plurality of divided data divided by the packet dividing means to generate one wireless frame signal, and transmits the generated wireless frame signal.
A program to realize.

(Appendix 13)
Divide the data to be sent into multiple parts
A wireless transmission method in which an error detection code is assigned to each of the plurality of divided data to generate one wireless frame signal, and the generated wireless frame signal is transmitted.

The programs described in each of the above-described embodiments and appendices may be stored in a storage device or recorded in a computer-readable recording medium. For example, the recording medium is a portable medium such as a flexible disk, an optical disk, a magneto-optical disk, and a semiconductor memory.

Although the present invention has been described above with reference to each of the above embodiments, the present invention is not limited to the above-described embodiments. Various changes that can be understood by those skilled in the art can be made to the structure and details of the present invention within the scope of the present invention.

1, 2 Communication device 11 Antenna 12 Wireless communication unit 13 Collision detection unit 14 Packet division / combination unit 15 Packet division / combination method determination unit 16 Storage unit 21 Redundant packet generation / removal unit 3 Transmission device 31 Packet division unit 32 Wireless frame signal Transmitter 4 Receiver 41 Wireless frame signal receiver 42 Collision detection unit 5 Wireless communication system 6 Wireless communication terminal 61 Collision detection unit 62 Wireless frame signal receiver

Claims (10)

A packet division unit that divides the data to be transmitted into multiple parts,
A transmission device including a radio frame signal transmission unit that assigns an error detection code to each of the plurality of divided data divided by the packet division unit to generate one radio frame signal, and transmits the generated radio frame signal. When,
A wireless frame signal receiving unit that receives the wireless frame signal transmitted by the transmitting device and extracts the plurality of divided data from the received wireless frame signal.
Based on the extraction result of the radio frame signal, indicating a collision occurring halfway transmitted from the transmission start time of the radio frame signals, a collision that occurs throughout, collisions on the middle transmission of a radio frame signal, any of the It has a collision detection unit that detects a collision situation, and a receiver having a collision detection unit.
The wireless frame signal receiving unit of the receiving device takes out the plurality of divided data by using the error detection code assigned to each of the plurality of divided data.
The collision detection unit of the receiving device determines the collision situation according to the position of the divided data that failed to be retrieved based on the position of the divided data that failed to be retrieved as a result of fetching the divided data using the error detection code. Wireless communication system to detect. The wireless communication system according to claim 1.
The radio frame signal receiving unit is configured to measure the strength of the received radio frame signal.
The collision detection unit is a wireless communication system that detects the collision situation based on the position of the divided data that failed to be retrieved and the strength of the received wireless frame signal. The wireless communication system according to claim 1 or 2.
When the collision detection unit fails to extract the divided data located at the front end of the plurality of divided data and succeeds in extracting the divided data located at the rear end, the transmission device transmits the wireless frame signal. A wireless communication system that detects the collision situation to the effect that it has occurred from the start point to the middle of transmission . The wireless communication system according to any one of claims 1 to 3.
When the collision detection unit succeeds in extracting the divided data located at the tip of the plurality of divided data and fails to extract the divided data at any position other than the tip, the wireless frame by the transmitting device. A wireless communication system that detects the collision situation to the effect that it has occurred during signal transmission. The wireless communication system according to any one of claims 1 to 4.
The packet division unit divides the data to be transmitted so that the number of bytes of the divided data located at the tip of the plurality of divided data is shorter than the number of bytes of the divided data located behind the divided data. Communications system. The wireless communication system according to any one of claims 1 to 4.
The packet division unit is a wireless communication system that divides the data to be transmitted at equal intervals based on predetermined parameters. The wireless communication system according to any one of claims 1 to 6.
The receiving device has a notification means for notifying the transmitting device that the collision detecting unit has detected the collision situation.
The transmitting device is a wireless communication system that redundantly transmits divided data at a position where a collision has occurred when the notification is received from the receiving device. A wireless frame signal receiving unit that receives a wireless frame signal generated by assigning an error detection code to each of the plurality of divided data and extracts the plurality of divided data from the received wireless frame signal.
Based on the extraction result of the radio frame signal, indicating a collision occurring halfway transmitted from the transmission start time of the radio frame signals, a collision that occurs throughout, collisions on the middle transmission of a radio frame signal, any of the It has a collision detection unit that detects the collision situation, and
The wireless frame signal receiving unit takes out the plurality of divided data by using the error detection code assigned to each of the plurality of divided data.
The collision detection unit detects the collision situation according to the position of the divided data that failed to be extracted based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code. Terminal. A radio frame signal generated by assigning an error detection code to each of the plurality of divided data is received, and the error detection code assigned to each of the plurality of divided data is used from the received radio frame signal. Then, each of the plurality of divided data is taken out,
As a result of extracting the divided data using the error detection code, the collision situation according to the position of the divided data that failed to be extracted is detected based on the position of the divided data that failed to be extracted.
The collision situation, a collision that occurs partway transmitted from the transmission start time of the radio frame signals, a collision that occurs throughout, collisions on the middle transmission of the radio frame signal, collision detection methods shows one of. For wireless communication terminals
A radio frame signal receiving means that receives a radio frame signal generated by assigning an error detection code to each of the plurality of divided data and extracts the plurality of divided data from the received radio frame signal.
Based on the extraction result of the radio frame signal, indicating a collision occurring halfway transmitted from the transmission start time of the radio frame signals, a collision that occurs throughout, collisions on the middle transmission of a radio frame signal, any of the Realize a collision detection means that detects the collision situation,
The wireless frame signal receiving means takes out the plurality of divided data by using the error detection code assigned to each of the plurality of divided data.
The collision detecting means is a program that detects the collision situation according to the position of the divided data that failed to be extracted based on the position of the divided data that failed to be extracted as a result of extracting the divided data using the error detection code.

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