Wireless device and wireless system

The present invention relates to wireless devices and wireless systems.

As a method of determining whether or not the receiver correctly receives the signal transmitted by the transmitter, a method using an affirmative response and a method using a negative response are known.

As a system that uses an acknowledgment (ACK), for example, there is a wireless LAN system. The receiver of the wireless LAN system transmits the ACK signal only when the signal transmitted by the transmitter can be correctly received.

On the other hand, as a system using a negative response (NACK: negative ACK), a one-to-one communication system is known as shown in Patent Document 1. Only one transmitter and one receiver belong to the one-to-one communication system, and they are less susceptible to interference from other radios. Therefore, it is more likely to succeed than the possibility of failing to receive the signal. The receiver of Patent Document 1 transmits the NACK signal only when the signal reception fails.

Since the response signal (ACK signal or NACK signal) is a control signal that does not include data, the throughput of the system decreases as the number of transmissions of the response signal increases. The throughput of the system can be improved by using either an acknowledgment or a negative response according to the propagation environment as in the wireless LAN system and the system shown in Patent Document 1.

Since there are multiple types of response signals such as ACK signal, NACK signal, and BA (Block ACK) signal, the transmitter adds information (response signal type, ReqACK Type) indicating which response signal to use in the header part of the signal. And send. The receiver demodulates the header part of the signal and returns the reception result using the response signal specified in the header part.

<p><patcit num="1"><text>Patent No. 4110522</text></patcit></p>

<p> If the propagation environment deteriorates and the receiver fails to receive the header portion of the signal, the receiver cannot demodulate the response signal type and cannot return the response signal.</p><p> When the transmitter requested the NACK signal, if there was no reply from the receiver, it could not be determined whether the signal was successfully received and there was no response, or the propagation environment deteriorated and the response could not be returned. There is a problem that a reception error cannot be detected.</p><p> The present invention has been made to solve this problem, and an object of the present invention is to provide a wireless device and a wireless system capable of reducing undetected reception errors even if the propagation environment deteriorates.</p>

<p> According to one aspect of the present invention, a receiving means for receiving a data signal having a header field and a data field including a response request for specifying either a positive response or a negative response, and success in receiving the header field and the data field. A determination means for determining a reception result indicating whether or not the data field has been received, and if the header field has been successfully received, the positive response or the negative response is transmitted according to the response request and the reception result of the data field. However, a wireless device including a transmission means for transmitting the negative response when the reception of the header field fails is provided.</p>

<p> According to the present invention, it is possible to provide a wireless device and a wireless system that can reduce undetected reception errors even if the propagation environment deteriorates.</p>

<figref num="1">The schematic which shows the wireless system.</figref><figref num="2">The figure which shows the packet switching example of the 1st wireless device and the 2nd wireless device.</figref><figref num="3">The figure which shows another example of the packet switching of the 1st wireless device and the 2nd wireless device.</figref><figref num="4">The figure which shows another example of the packet switching of the 1st wireless device and the 2nd wireless device.</figref><figref num="5">The figure which shows the packet composition example of the wireless system which concerns on Example 1.</figref><figref num="6">The figure which shows the packet switching example of the wireless system which concerns on Example 1. FIG.</figref><figref num="7">The figure which shows the wireless device which concerns on Example 1.</figref><figref num="8">The figure which shows the packet composition example of the wireless system which concerns on the modification 1 of Example 1.</figref><figref num="9">The figure which shows the packet switching example of the wireless system which concerns on the modification 1 of Example 1.</figref><figref num="10">The figure which shows the packet composition example of the wireless system which concerns on Example 2.</figref><figref num="11">The figure which shows the packet switching example of the wireless system which concerns on Example 2.</figref><figref num="12">The figure which shows the packet switching example of the wireless system which concerns on Example 3. FIG.</figref><figref num="13">The figure which shows the packet switching example of the wireless system which concerns on Example 4. FIG.</figref>

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following examples, the same operation will be performed for the parts with the same number, and the description thereof will be omitted.

First, the outline of the wireless system of the present invention will be described with reference to FIG. The wireless system of FIG. 1 includes first to third wireless devices 1 to 3. In the wireless system of the present invention, it is assumed that the communication range of the wireless device is wide and is about several tens of cm. In the case of short-range communication in which the communication range of the wireless device is several tens of centimeters in this way, the number of wireless devices connected to one wireless device is at most several. In the example of FIG. 1, the number of wireless devices provided in the wireless system is set to 3, but the number is not limited to this and may be about 2 to 5. In the example of FIG. 1, the first wireless device 1 and the second wireless device 2 are performing wireless communication. Further, the first wireless device 1 and the third wireless device 3 are performing wireless communication. In the following description, wireless communication between the first wireless device 1 and the second wireless device 2 will be described, but even if the wireless communication is between the first and third wireless devices 1 and 3, the second and third wireless devices Needless to say, it may be wireless communication between a few.

A wireless communication system in order to simplify and streamline the connection compared to the method in which one wireless device transmits a broadcast signal (for example, Beacon signal) as an access point and random backoff control is performed each time each wireless device transmits. Communicates as follows.

First, when the data to be transmitted to the second wireless device 2 is generated, the first wireless device 1 transmits a connection request signal to the second wireless device 2 by using, for example, random backoff control. The second wireless device 2 receives the connection request signal and transmits the connection permission signal to the first wireless device 1, so that the first and second wireless devices 1 and 2 establish the connection.

After establishing the connection, the first wireless device 1 divides the data to be transmitted into a plurality of pieces and generates a plurality of divided data. The first wireless device 1 generates a data signal from the divided data and transmits it to the second wireless device 2. This data signal includes a response request (response signal type) indicating the type of response signal. When the second wireless device 2 receives the data signal, the second wireless device 2 transmits the response signal according to the response request and the reception result of the data signal.

(Communication example 1) With reference to FIG. 2, the communication between the first and second wireless devices 1 and 2 after the connection is established by the first wireless device 1 as the transmitter and the second wireless device 2 as the receiver will be described. It is assumed that the first and second wireless devices 1 and 2 each have a receive buffer having a sufficient size for each other. Further, it is assumed that the first wireless device 1 knows the size of the receive buffer of the second wireless device 2. Hereinafter, the solid line signal in the figure indicates a transmission signal, and the dotted line signal indicates a reception signal.

The first wireless device 1 transmits the data signal D101 after the connection is established. The data signal D101 has a header field and a data field (not shown). The header field contains information indicating which type of response signal is used (response request) and information indicating the number of the transmitted data signal (SN: Sequence Number). The data field contains divided data obtained by dividing the data to be transmitted. When transmitting the data signal D101, the first wireless device 1 requests an ACK signal as a response. Therefore, the information requesting the ACK signal (ACK request) and the information SN = 1 are described in the header field of the data signal D101.

When the second wireless device 2 receives the data signal D101, it determines whether or not the header field and the data field can be demodulated correctly. It is assumed that the second wireless device 2 succeeds in receiving the header field / data field when the data signal D101 can be received and the header field / data field can be correctly demolished. Even if the second wireless device 2 can receive the data signal D101, if the header field / data field cannot be demolished correctly, it is assumed that the reception of the header field / data field fails.

If the header field and the data field can be received correctly, the second wireless device 2 stores the divided data Data1 included in the data field in the reception buffer B2. The second wireless device 2 sends the divided data Data1 from the receive buffer B2 to the upper layer (Upper). Further, the second wireless device 2 determines that the first wireless device 1 is requesting the ACK signal by demodulating the header field, and returns the ACK signal A101 to the first wireless device 1. Further, the second wireless device 2 stores the SN (= 1) of the data signal D101.

When the first wireless device 1 receives the ACK signal A101, it transmits the data signal D102 with SN = 2. The first wireless device 1 shall set a negative response as a response request for the data signal D102 (NACK request). For example, the first wireless device 1 determines that the propagation environment is good because the data signal D101 is correctly transmitted to the second wireless device 2, and switches from the ACK request to the NACK request. Further, the first wireless device 1 may determine whether the propagation environment is good or bad from the reception result of the ACK signal A101, and determine the switching from the ACK request to the NACK request.

It is assumed that the second wireless device 2 receives the data signal D102, but fails to receive the header field and the data field due to the deterioration of the propagation environment. The second wireless device 2 does not store anything in the receive buffer B2 because the reception of the data field has failed. Since the second wireless device 2 has failed to receive the header field, the response request cannot be determined. Therefore, the second wireless device 2 does not return either the ACK signal or the NACK signal.

Since the NACK signal is not returned even after a certain period of time has passed after the data signal D102 is transmitted, the first wireless device 1 determines that the data signal D102 has been successfully transmitted. The first wireless device 1 transmits the next data signal D103. Negative response is also set as the response signal type for the data signal D103.

The second wireless device 2 receives the data signal D103. The second wireless device 2 determines whether or not the header field and the data field have been successfully received. The second wireless device 2 determines whether or not to transmit a response signal from the response request included in the header field. In this case, the response signal type is the NACK signal, and since the data signal D103 has been successfully received, the second wireless device 2 does not return the response signal.

The second wireless device 2 stores the divided data DATA3 included in the data field in the reception buffer B2. At this time, the second wireless device 2 determines from the reception result of the header field that the SN of the data signal D103 is 3, which is not continuous with the SN (= 1) of the previously received data signal D101. That is, it is determined that there is a data signal D102 that has not been received between the data signal D101 received last time and the data signal D103 received this time, and the second wireless device 2 stores the divided data included in the data signal D102. The divided data DATA3 is stored in the receive buffer B2 with an available area. Further, the second wireless device 2 stores the SN (= 3) of the data D103 received this time and the SN (= 2) of the data signal D102 not received this time.

Since the NACK signal is not returned even after a certain period of time has passed since the first wireless device 1 transmits the data signal D103, it is determined that the data signal D103 has been successfully transmitted. The first and second wireless devices 1 and 2 similarly transmit and receive data signals D104 and D105.

In the first wireless device 1, the total of the divided data DATA2,3,4,5 transmitted by setting the NACK request as the response signal type, the divided data DATA6 scheduled to be transmitted this time, and the divided data DATA7 scheduled to be transmitted next time is , When the size of the receive buffer B2 of the second wireless device 2 is larger than that of the receive buffer B2, that is, when the divided data DATA6 is stored in the receive buffer B2 as shown in FIG. , The first wireless device 1 transmits the data signal D106 including the divided data DATA6 by setting the ACK request as the response request.

When the second wireless device 2 receives the data signal D106, it determines whether or not the header field and the data field have been successfully received. If the header field and the data field can be received correctly, the divided data Data6 included in the data field is stored in the receive buffer B2. Further, the second wireless device 2 determines that the first wireless device 1 is requesting the ACK signal by demodulating the header field, and returns the ACK signal A106 to the first wireless device 1. At this time, the second wireless device 2 includes the unreceived SN (SN = 2 in the case of FIG. 2) in the ACK signal A106.

When the first wireless device 1 receives the ACK signal A106, it retransmits the data signal corresponding to the SN that has not been received. In the case of FIG. 2, the first wireless device 1 retransmits the data signal D102. At this time, the first wireless device 1 sets the response request of the data signal D102 to the ACK request.

When the second wireless device 2 receives the data signal D102, it determines whether or not the header field and the data field have been correctly received. If the header field and data field can be received correctly, the divided data Data2 included in the data field is stored in the open area of the receive buffer B2. Sorting the divided data stored in the receive buffer B2 in the order of SN in this way is called reordering of the (receive) buffer. Further, the second wireless device 2 determines that the first wireless device 1 is requesting the ACK signal by demodulating the header field, and returns the ACK signal A'102 to the first wireless device 1. The second wireless device 2 sends the divided data Data2 to DATA6 from the reception buffer B2 to the upper layer (Upper).

As described above, when the first and second wireless devices 1 and 2 have a sufficiently large reception buffer and the first wireless device 1 knows the size of the reception buffer B2 of the second wireless device 2. , The first wireless device 1 sets the response communication request of the data signal to the ACK request according to the size of the receive buffer B2 of the second wireless device 2. That is, when the total amount of divided data transmitted by setting the NACK request is larger than the size of the receive buffer B2 of the second wireless device 2, the first wireless device 1 sets the ACK request for the next transmitted data. And send. As a result, even if the second wireless device 2 fails to receive the data signal D102, the first wireless device 1 can reliably retransmit the data signal D102.

(Communication example 2) Another communication example of the first and second wireless devices 1 and 2 will be described with reference to FIG. In the example shown in FIG. 3, once the second wireless device 2 fails to receive the data signal, the divided data is not stored in the reception buffer even if the data signal is successfully received thereafter, and the response signal is transmitted according to the response request. To do. Specifically, it will be described with reference to FIG. Since it is the same as FIG. 2 until the first wireless device 1 transmits the data signal D103, the description thereof will be omitted.

When the second wireless device 2 receives the data signal D103, it determines whether or not the header field and the data field have been successfully received. When the header field and the data field are correctly received, the divided data Data3 included in the data field is stored in the reception buffer B2 in the communication example 1, but the reception of the data signal D102 has failed once in this example. Therefore, the second wireless device 2 does not store the divided data Data3 in the receive buffer B2. However, since the second wireless device 2 has succeeded in receiving the header field, the second wireless device 2 returns the response signal to the first wireless device 1 in accordance with the response request. In this case, since the response request is a NACK request and the data field has been successfully received, the second wireless device 2 does not return the response signal.

Since the NACK signal is not returned even after a certain period of time has passed since the first wireless device 1 transmits the data signal D103, it is determined that the data signal D103 has been successfully transmitted. The first and second wireless devices 1 and 2 similarly transmit and receive the data signal D104.

The first wireless device 1 periodically sets an ACK request and transmits a data signal even when a NACK request is set as a response request and a plurality of data signals are transmitted. In the example of FIG. 3, the second wireless device 2 sets an ACK request as a response request and transmits the data signal D105.

When the second wireless device 2 receives the data signal D105, it determines whether or not the header field and the data field have been successfully received. Although the header field and data field have been received correctly, the divided data Data5 included in the data field is not stored in the receive buffer B2. Further, the second wireless device 2 determines that the first wireless device 1 is requesting the ACK signal by demodulating the header field, and returns the ACK signal A105 to the first wireless device 1. At this time, the second wireless device 2 includes the SN (= 1) corresponding to the divided data DATA1 stored in the receive buffer B2 at the end in the ACK signal A105 and returns.

When the first wireless device 1 receives the ACK signal A105, it retransmits the data signal D102 corresponding to the SN (= 2) next to the SN = 1 included in the ACK signal A105. At this time, the first wireless device 1 sets the response request of the data signal D102 to the ACK request.

When the second wireless device 2 receives the data signal D102, it determines whether or not the header field and the data field have been correctly received. If the header field and the data field can be received correctly, the divided data Data2 included in the data field is stored in the receive buffer B2. The second wireless device 2 sends the divided data Data2 from the reception buffer B2 to the upper layer (Upper). Further, the second wireless device 2 determines that the first wireless device 1 is requesting the ACK signal by demodulating the header field, and returns the ACK signal A'102 to the first wireless device 1.

When the first wireless device 1 receives the ACK signal A'102, it retransmits the data signal D103. The response request of the data signal D103 may be an ACK request or an NACK request. The example in Fig. 3 shows the case where the NACK request is set.

When the second wireless device 2 receives the data signal D103, it determines whether or not the header field and the data field have been correctly received. If the header field and the data field can be received correctly, the divided data Data3 included in the data field is stored in the receive buffer B2. The second wireless device 2 sends the divided data Data3 from the reception buffer B2 to the upper layer (Upper). Further, the second wireless device 2 determines that the first wireless device 1 is requesting the NACK signal by demodulating the header field, and does not return the response signal to the first wireless device 1.

Similarly, the first wireless device 1 transmits the data signal D104 or later.

As described above, if reception fails once, the second wireless device 2 does not store the received divided data in the reception buffer B2 and responds even if the data signal is successfully received until the next response signal is transmitted. The signal is returned including the SN corresponding to the divided data finally stored in the receive buffer B2. When the response signal includes an SN other than the SN of the last transmitted data signal, the first wireless device 1 transmits the last data from the data signal corresponding to the next number of the SN included in the response signal. Retransmission is performed sequentially up to the signal. As a result, even if the first wireless device 1 does not know the receive buffer size of the second wireless device 2, the first wireless device 1 can reduce the undetected reception error and can reliably retransmit the data signal. ..

(Communication example 3) FIG. 4 describes another communication example of the first and second wireless devices 1 and 2. In the example shown in FIG. 4, unlike the example shown in FIG. 3, the divided data is stored in the reception buffer when the data signal received thereafter is successfully received even after the reception fails once. Details will be described with reference to FIG. It should be noted that the description is omitted because it is the same as in FIGS. 2 and 3 until the first wireless device 1 transmits the data signal D103.

Upon receiving the data signal D103, the second wireless device 2 demodulates the header field and the data field. The second wireless device 2 determines whether or not the header field and the data field have been successfully received. In the example of FIG. 4, since the header field and the data field of the data signal D103 are correctly received by the second wireless device 2, the divided data Data3 included in the data field is stored in the reception buffer B2. However, since the reception of the previous data signal D102 has failed, the divided data Data3 is not sent from the reception buffer B2 to the upper layer (Upper). Further, the second wireless device 2 determines that the first wireless device 1 is requesting the NACK signal by demodulating the header field, and does not return the response signal to the first wireless device 1.

Since the NACK signal is not returned even after a certain period of time has passed since the first wireless device 1 transmits the data signal D103, it is determined that the data signal D103 has been successfully transmitted. The first and second wireless devices 1 and 2 similarly transmit and receive the data signal D104.

The first wireless device 1 periodically sets the ACK request and transmits the data signal even when the NACK request is set as the response signal type and a plurality of data signals are transmitted. In the example of FIG. 4, the second wireless device 2 sets the ACK request as the response signal policy and transmits the data signal D105.

Upon receiving the data signal D105, the second wireless device 2 demodulates the header field and the data field. The second wireless device 2 determines whether or not the header field and the data field have been successfully received. Here, it is assumed that the size of the reception buffer B2 of the second wireless device 2 is small and the divided data Data5 cannot be stored in the reception buffer B2. In this case, even if the data field is successfully received, the second wireless device 2 does not store the divided data Data5 in the reception buffer B2.

By demodulating the header field of the data signal D105, the second wireless device 2 determines that the first wireless device 1 is requesting the ACK signal, and returns the ACK signal A105 to the first wireless device 1. At this time, the second wireless device 2 includes the SN (SN = 2 and SN = 5 in the example of FIG. 4) of the data signal that could not be stored in the receive buffer B2 at the end in the ACK signal A105 and returns the data signal. Alternatively, if there is one SN to be notified by the ACK signal A105, the ACK signal A105 is returned including SN = 2, and after receiving the data signal D'102 with SN = 2, the response signal of the data signal D'102 is received. You may reply to the ACK signal A'102, which is, including SN = 5.

When the first wireless device 1 receives the ACK signal A105, it retransmits the data signal D102 corresponding to the smaller SN (SN = 2) of the SN = 2,5 included in the ACK signal A105. At this time, the first wireless device 1 sets the response signal policy of the data signal D102 to the ACK request.

Upon receiving the data signal D102, the second wireless device 2 demodulates the header field and the data field. The second wireless device 2 determines whether or not the header field and the data field can be received correctly. If the header field and the data field can be received correctly, the divided data Data2 included in the data field is stored in the receive buffer B2. The second wireless device 2 reorders the reception buffer B2 and sends the divided data Data2 to Data4 stored in the reception buffer B2 to the Upper. Further, the second wireless device 2 determines that the first wireless device 1 is requesting the ACK signal by demodulating the header field, and returns the ACK signal A'102 to the first wireless device 1.

When the first wireless device 1 receives the ACK signal A'102, it retransmits the data signal D105 corresponding to SN = 5. The response request of the data signal D105 may be an ACK request or a NACK request, but in FIG. 4, it is set to the NACK request.

When the second wireless device 2 receives the data signal D105, it demodulates the header field and the data field. The second wireless device 2 determines whether or not the header field and the data field can be received correctly. If the header field and the data field can be received correctly, the divided data Data5 included in the data field is stored in the receive buffer B2. The second wireless device 2 sends the divided data Data5 from the reception buffer B2 to the upper layer (Upper). Further, the second wireless device 2 determines that the first wireless device 1 is requesting the NACK signal by demodulating the header field, and does not return the response signal to the first wireless device 1.

As described above, even if the reception fails once, if the subsequent data signal is successfully received, the second wireless device 2 stores the divided data included in the successful data signal in the reception buffer B2. When returning the ACK signal, the second wireless device 2 includes the SN of the data signal that failed to be received or the SN of the data signal that could not be stored due to the overflow of the reception buffer B2 in the ACK signal and returns the ACK signal. The first wireless device 1 may retransmit the data signal corresponding to the SN included in the ACK signal, and the number of retransmissions can be reduced as compared with the case of FIG.

<p>Example 1 of the present invention will be described. The wireless system according to the first embodiment differs from the wireless system shown in FIG. 1 in the configuration of the ACK signal or NACK signal returned by the second wireless device 2 and the communication sequence between the first and second wireless devices 1 and 2. Since they have the same configuration, they will be described using the same reference numerals. The configurations of the first to third wireless devices 1 to 3 will be described later.</p><p>The packet configuration of the data signal transmitted and received by the first to third wireless devices 1 to 3 will be described with reference to FIG. The data signal has a header field (also called a MAC header) and a data field (also called a Frame body). The data field contains a payload part (payload) and error control information (FCS: Frame Check Sequence). The payload part (payload) contains divided data obtained by dividing the data to be transmitted.</p><p>Header fields include Req ACK Type field and SN field. The wireless system according to the present embodiment communicates in one of an ACK mode in which the reception result is notified only by the ACK signal, an NACK mode in which the reception result is notified only by the NACK signal, and a mixed mode in which the reception result is notified by either the ACK signal or the NACK signal. Do. The Req ACK Type field describes the type of signal that notifies the reception result when a data signal is received. The Req ACK Type field contains information (response request) indicating which type of response signal is used. When the wireless device requests the reply of the ACK signal after receiving the data signal, the ACK request is described in the Req ACK Type field. If the wireless device requests a reply of the NACK signal after receiving the data signal, the NACK request is described in the Req ACK Type field. In the SN field, information indicating the number of the transmitted data signal (SN:) Sequence Number) is included. In addition to the above-mentioned fields, the header field may include destination address information, source address information, and the like. Further, the header field may be divided into internal fields such as common header and sub header. In this case, a CRC bit for error detection is added at the end of each header. Further, in this case, the destination address information, the source address information, and the like are generally included in the common header, and the Req ACK Type and the like are included in the sub header. In this case, if the common header is correct and the sub header is incorrect, NACK is sent.</p><p>Next, with reference to FIG. 6, communication between the first and second wireless devices 1 and 2 will be described after the connection is established with the first wireless device 1 as the transmitter and the second wireless device 2 as the receiver. Since it is the same as FIG. 2 until the first wireless device 1 transmits the data signal D102, the description thereof will be omitted.</p><p>It is assumed that the second wireless device 2 receives the data signal D102, but fails to demodulate the header field and the data field due to the deterioration of the propagation environment. The second wireless device 2 does not store anything in the receive buffer B2 because the reception of the data field has failed. The second radio device 2 also fails to receive the header field. Here, in the examples shown in FIGS. 2 to 4, when the second wireless device 2 fails to receive the header field, the response request cannot be determined and neither the ACK signal nor the NACK signal is returned. However, the example shown in FIG. Then, when the second wireless device 2 fails to receive the header field, it returns the NACK signal A602. In this case, the first wireless device 1 transmits the NACK signal even if the ACK request is described in the Req ACK Type field.</p><p>When the first wireless device 1 receives the NACK signal A602, it retransmits the data signal D102. In FIG. 6, the first wireless device 1 retransmits the same signal as the previously transmitted data signal D102. For example, the transmission method may be changed to a method with a lower error rate, or an ACK request may be sent to the Req ACK Type field. Retransmission may be performed by a transmission method that is highly likely to be received even if the propagation environment deteriorates, such as by describing.</p><p>The second wireless device 2 succeeds in receiving the data signal D102. The second wireless device 2 determines whether or not to transmit a response signal from the response request included in the header field. In this case, since the response request is a NACK signal and the data signal D102 has been successfully received, the second wireless device 2 does not return the response signal. Further, the second wireless device 2 stores the divided data DATA2 included in the data field in the reception buffer B2.</p><p>Since the NACK signal is not returned even after a certain period of time after the data signal D102 is transmitted, the first wireless device 1 determines that the data signal D102 has been successfully transmitted. The first wireless device 1 transmits the data signal D103.</p><p>The second wireless device 2 receives the data signal D103. The second wireless device 2 determines whether or not the header field and the data field have been successfully received. In the case of FIG. 6, the header field of the data signal D103 is successfully received, but the data field is not received. The second wireless device 2 returns an NACK signal to the first wireless device 1 based on the reception result of the header field.</p><p>When the first wireless device 1 receives the NACK signal from the second wireless device 2, it retransmits the data signal D103. The second wireless device 2 receives the data signal D103. Since the data signal D103 has been successfully received this time, the second wireless device 2 stores the divided data DATA3 in the reception buffer B2 and does not return the response signal.</p><p>Since the NACK signal is not returned even after a certain period of time after the data signal D103 is retransmitted, the first wireless device 1 determines that the data signal D103 has been successfully transmitted. The first wireless device 1 transmits the data signal D104. In the mixed mode, the first wireless device 1 transmits the data signal including the ACK request at regular intervals (or a fixed number of times) even when the data signal including the NACK request is transmitted. In FIG. 6, the first wireless device 1 transmits the data signal D104 including the ACK request.</p><p>The second wireless device 2 receives the data signal D104. The second wireless device 2 stores the divided data DATA3 included in the data field in the reception buffer B2. By demodulating the header field, the second wireless device 2 determines that the first wireless device 1 is requesting the ACK signal, and returns the ACK signal A604. The second wireless device 2 sends the divided data DATA2 to DATA4 to Upper. The divided data may be sent to Upper when a continuous SN data signal is received, and certain conditions such as when a data signal including an ACK request is received and the reception buffer B2 is full are satisfied. It may be sent to Upper as a trigger.</p><p>As described above, when the second wireless device 2 fails to receive the header field, it returns a NACK signal regardless of the type of response request. As described above, when there are a common header and a sub header in the header field, a NACK signal is transmitted at least when the header in which the response request type is described is incorrect.</p><p>Next, a configuration example of the wireless device according to this embodiment will be described with reference to FIG. 7. FIG. 7 shows the configuration of the first wireless device 1, but the second and third wireless devices 2 and 3 have the same configuration.</p><p>The first wireless device 1 includes an antenna 10, a wireless unit 20, a modulation / demodulation unit 30, and a MAC processing unit 40. The modulation / demodulation unit 30 includes a modulation unit 31 and a demodulation unit 32, and the MAC processing unit 40 includes a transmission unit 41, a reception unit 42, a response signal control unit 43, a response mode management unit 44, and a reception buffer 45 (reception buffer B2). Including.</p><p> First, the operation of the first wireless device 1 at the time of signal transmission will be described. At the time of signal transmission, the data output from the upper layer processing unit (not shown) is input to the transmission unit 41. The transmission unit 41 performs processing such as adding a header field and generates a data signal. At this time, according to the instruction of the response signal control unit 44, the information indicating the response request (ACK request / NACK request) is described in the Req ACK Type field.</p><p> The generated transmission signal is output to the modulation unit 31. The modulation unit 31 performs processing such as coding processing, modulation processing, and addition of a physical header on the data signal to generate a physical data signal. The radio unit 20 performs D / A conversion processing, up-conversion, and other processing on the physical data signal to generate a transmission signal, and transmits the transmission signal via the antenna 10. In FIG. 7, a block that generates a data signal by performing processing such as adding a header field is referred to as a transmission unit, but a portion having a transmission function of the transmission unit 41, the modulation unit 31 and the radio unit 20 in FIG. May be collectively referred to as a transmission unit or a transmission means.</p><p> Next, the operation of the first wireless device 1 at the time of receiving a signal will be described. The received signal received via the antenna 10 is subjected to processing such as down-conversion and A / D conversion by the radio unit 20 and converted into a physical data signal. The demodulation unit 32 performs processing such as demodulation processing and analysis of the physical header on the physical data signal to generate the data signal. The receiving unit 42 performs processing such as analysis of the header field of the data signal to generate divided data.</p><p> In the above example, the block that performs processing such as header field analysis and generates divided data is referred to as the receiving unit 42, but the portion having the receiving function of the receiving unit 42, the demodulation unit 32, and the wireless unit 20 in FIG. May be collectively referred to as a receiving unit or a receiving means. The receiving unit (receiving means) receives a data signal having a header field including response information specifying either an acknowledgment or a negative response and a data field including divided data.</p><p> The response signal control unit 44 receives the header field and the data field from the reception unit 42, and determines whether or not the reception of the header field and the data field is successful. That is, the response signal control unit 44 operates as a determination means for determining a reception result indicating whether or not the header field and the data field have been successfully received.</p><p> If the reception of the header field fails, the response signal control unit 44 instructs the transmission unit 41 to return the NACK signal. The transmission unit 41 returns the NACK signal to the communication partner. The split data is not stored in the receive buffer 45 regardless of whether the data field has been successfully received.</p><p> When the header field is successfully received and the data field is not received, the response signal control unit 44 instructs the transmission unit 41 to return the response signal according to the response request described in the Req ACK Type field. The response signal control unit 44 instructs the transmission unit 41 to return the NACK signal when the NACK request is described in the Req ACK Type field. When the ACK request is described in the Req ACK Type field, the response signal control unit 44 does not instruct the transmission unit 41 to return the response signal. Further, since the reception of the data field has failed, the divided data is not stored in the reception buffer 45.</p><p> When the header field and the data field are successfully received, the response signal control unit 44 instructs the transmission unit 41 to return the response signal according to the response request described in the Req ACK Type field. The response signal control unit 44 instructs the transmission unit 41 to return the ACK signal when the ACK request is described in the Req ACK Type field. When the NACK request is described in the Req ACK Type field, the response signal control unit 44 does not instruct the transmission unit 41 to return the response signal. The receiving unit 42 stores the divided data in the receiving buffer 45. The receive buffer sends the divided data stored when data is input or when certain conditions are met to Upper (not shown). Certain conditions include, for example, the case where the divided data having the SN of the divided data sent to the Upper last time and the continuous SN is input, or the case where the receive buffer is full.</p><p> In addition, instead of the response signal control unit 44, the reception unit 42 may operate as a determination means for determining a reception result indicating whether or not the header field and the data field have been successfully received. In this case, the receiving unit 42 passes the reception result of the header field and the data field and the response request described in the Req ACK Type field of the header field to the response signal control unit 44. The response signal control unit 44 sends the transmission unit 41 to return the response signal to the first wireless device 1 based on the reception result of the header field and the data field and the response request described in the Req ACK Type field of the header field. Instruct.</p><p> The transmission unit 41 transmits a response signal based on the instruction of the response signal control unit 44. The transmission unit 41 transmits an ACK signal or a NACK signal according to the response request and the reception result of the data field when the header field is successfully received, and transmits the NACK signal when the header field reception is unsuccessful. .. Since the specific method of returning the response signal is the same as the method of transmitting the data signal except that the data signal replaces the response signal, the description thereof will be omitted.</p><p>As described above, in the wireless system according to the first embodiment, when the reception of the header field fails, the NACK signal is returned regardless of the type of the response request. As a result, even if the propagation environment deteriorates and the reception of the header field fails, the undetected reception error can be reduced, and the data signal can be reliably retransmitted.</p><p>(Modification example 1) A modification 1 of the first embodiment will be described. In the first modification, a method for surely switching the response mode will be described.</p><p>FIG. 8 describes a packet configuration of data signals transmitted and received by the first to third wireless devices 1 to 3 of the first modification. The data signal of FIG. 8 has a reply mode filed in the header field in addition to the packet configuration of the data signal of FIG. Similar to the first embodiment, the wireless system according to the second embodiment has an ACK (affirmative response) mode for notifying the reception result only with an ACK signal, an NACK (negative response) mode for notifying only the NACK signal, and an ACK signal or a NACK signal. Communicate in one of the mixed modes of notifying using either of. The reply mode filed stores information indicating whether to communicate in one of the response modes.</p><p>Next, with reference to FIG. 9, communication between the first and second wireless devices 1 and 2 will be described after the connection is established with the first wireless device 1 as the transmitter and the second wireless device 2 as the receiver. Here, a case where the first and second wireless devices 1 and 2 communicate in the ACK mode and communicate in the mixed mode based on the notification from the first wireless device 1 will be described.</p><p>The first wireless device 1 transmits a data signal D901 containing information indicating an ACK mode in the reply mode filed of the header field and an ACK request in the Req ACK Type field.</p><p>The second wireless device 2 receives the data signal D901. In FIG. 9, since the header field and the data field have been successfully received, the second wireless device 2 returns the ACK signal A901 to the first wireless device 1. Here, when the second wireless device 2 analyzes the header field, it notifies the response mode management unit 43 of the ACK mode described in the reply mode filed.</p><p>When the first wireless device 1 receives the ACK signal A901, it then transmits the data signal D902. Here, the first wireless device 1 switches the response mode from the ACK mode to the NACK mode. The first wireless device 1 transmits a data signal D902 containing information indicating an NACK mode in the reply mode filed of the header field and a NACK request in the Req ACK Type field.</p><p>Here, it is assumed that the second wireless device 2 fails to receive the header field and the data field of the data signal D902. Since the second wireless device 2 has failed to receive the header field, the second wireless device 2 returns the NACK signal A902 to the first wireless device 1.</p><p>When the first wireless device 1 receives the NACK signal A902, it retransmits the data signal D902.</p><p>It is assumed that the second wireless device 2 simply returns a response signal according to the response mode stored in the response mode management unit 43. As shown in FIG. 9, when the second wireless device fails to receive the transmission data transmitted by the first wireless device 1 after switching from the ACK mode to the NACK mode, the second wireless device 2 is said to be in the ACK mode. Judging, the second wireless device 2 does not return the ACK signal. Therefore, the first wireless device 1 does not notice that the second wireless device 2 has failed to receive the data signal D902. On the other hand, as shown in this modification, the second wireless device 2 fails to receive the data signal by returning the NACK signal when the second wireless device 2 fails to receive the header field. Can be detected by the first wireless device 1.</p><p>Here, the case where the first wireless device 1 notifies the response mode each time a data signal is transmitted has been described, but the response mode is notified only when the first wireless device 1 switches the response mode. May be good. Further, the response mode is not limited to the three types of ACK mode, NACK mode, and mixed mode, and communication may be performed by switching any two of the three types.</p>

<p>Next, Example 2 according to the present invention will be described. The wireless system according to the present embodiment is different from the first embodiment in that a plurality of frames are aggregated into one packet and transmitted.</p><p>FIG. 10 shows a packet configuration example of the data signal according to the second embodiment. The data signal has a MAC common header and a plurality of subframes having a MAC sub header and a Frame body. Hereinafter, as shown in FIG. 10, a data signal having a plurality of subframes is referred to as a multi-data signal. The MAC sub header contains a Req ACK Type field that indicates the type of response signal that alters the reception result of the frame body. In addition, the MAC sub header includes a frame length field indicating the length of the frame body (or the length of the subframe). The second wireless device 2 receives the data signal and analyzes the frame length field of the MAC sub header to grasp the position of the next MAC sub header.</p><p>Next, with reference to FIG. 11, communication between the first and second wireless devices 1 and 2 will be described after the connection is established with the first wireless device 1 as the transmitter and the second wireless device 2 as the receiver. Here, it is assumed that the second wireless device 2 returns a response signal using Block ACK (BA) or Negative Block ACK (NBA).</p><p>Block ACK is a response signal to be returned when there is even one data field that could be received correctly, and Negative Block ACK is a response signal to be returned when there is even one data field that failed to be received. .. Both consist of bitmaps.</p><p>The first wireless device 1 transmits the multi-data signal D111. Information indicating a BA request is described in the ACK Type field of each MAC sub header of the multi-data signal.</p><p>When the second wireless device 2 receives the multi-data signal D111, it analyzes in order from the first MAC common header. In the example of FIG. 10, since all the headers (MAC common header and MAC sub header) and data (plural frame bodies) of the multi-data signal D111 have been successfully received, the second wireless device 2 has all the frame bodies. The BA signal A111 indicating that the reception was successful is returned.</p><p>When the first wireless device 1 receives the BA signal A111, it transmits the multi-data signal D112. Information indicating the NBA request is described in the ACK Type field of each MAC sub header of the multi-data signal.</p><p>When the second wireless device 2 receives the multi-data signal D112, it analyzes in order from the first MAC common header. As described above, the second wireless device 2 knows the position of the second MAC sub header by analyzing the first MAC sub header of the multi-data signal D112. When the second wireless device 2 fails to receive the first MAC sub header of the multi-data signal D112, as a method of detecting the next Sub frame, for example, the head of the next MAC sub header is set to 1 There is known a method of finding a place where CRC is OK by shifting them one by one. In general, if the reception of the first MAC sub header of the multi-data signal D112 fails, there is a high possibility that the subsequent reception of the MAC sub header will fail. Therefore, if the second wireless device 2 of this embodiment fails to receive the first MAC sub header of the multi-data signal D112, the subsequent MAC sub The process of searching for the header is omitted, and the NACK signal is returned regardless of the response signal requested by the first wireless device 1. When the second wireless device 2 fails to receive the first MAC sub header of the multi-data signal D112, it returns the NBA signal A112 as a response signal.</p><p>As described above, if reception of the MAC sub header arranged first in the second wireless device 2 and the multi-data signal D112 of the wireless system according to this embodiment fails, regardless of the information described in the ACK Type field. Reply NBA signal. If the reception of the first MAC sub-header of the multi-data signal D112 fails, the subsequent reception of the MAC sub-header is likely to fail, so the second wireless device 2 fails to receive the multi-data signal. If this happens, the first wireless device 1 can reduce the undetected reception error that the second wireless device 2 mistakenly determines as having succeeded in receiving the multi-data signal, and the second wireless device 2 can be reduced. Can reduce the detection process as compared with the case of detecting all the MAC sub headers included in the multi-data signal D112.</p><p>The configurations of the first and second wireless devices 1 and 2 according to the present embodiment are shown in FIG. 7, except that the transmitting unit 41 transmits the multi-data signal and the receiving unit 42 receives the multi-data. Since the configuration is the same as that of the wireless device, the description thereof will be omitted.</p><p>The MAC sub header in FIG. 10 corresponds to the MAC header in FIG. 5, and the Frame body in FIG. 10 corresponds to the Frame body in FIG. That is, the first wireless device 1 of the present embodiment aggregates a plurality of data signals shown in FIG. 5 and transmits a multi-data signal generated by attaching a MAC common header.</p>

<p>Example 3 according to the present invention will be described with reference to FIG. The wireless system of the third embodiment is different from the first and second embodiments in that the NACK signal includes information indicating whether the reception of the header field has failed or the reception of the data field has failed.</p><p>With reference to FIG. 12, communication between the first and second wireless devices 1 and 2 will be described after the connection is established with the first wireless device 1 as the transmitter and the second wireless device 2 as the receiver. Since it is the same as FIG. 2 until the first wireless device 1 transmits the data signal D102, the description thereof will be omitted.</p><p>It is assumed that the second wireless device 2 receives the data signal D102 but fails to demodulate the header field and the data field due to the deterioration of the propagation environment. Since the demodulation of the header field has failed, the response signal type cannot be determined, but the second radio device 2 returns the NACK signal A122. This NACK signal A122 contains Header error information indicating that reception of the header field has failed. This Header error information may be expressed by setting a 1-bit flag on the NACK signal A122.</p><p>The first wireless device 1 receives the NACK signal A122. Since the NACK signal A122 contains Header error information, the first wireless device 1 describes the ACK request in the Req ACK Type field and transmits the data signal D102 when retransmitting the data signal D102.</p><p>Since the other configurations and operations are the same as those of the wireless system of the first embodiment, the description thereof will be omitted.</p><p>As described above, the second wireless device 2 of the present embodiment includes information indicating whether or not the reception of the header field has failed in the NACK signal A122. Generally, header fields are transmitted in a manner that is more error tolerant than data fields. Therefore, if the reception of the header field fails, it is highly possible that the propagation environment is very bad. Therefore, in the wireless system according to the present embodiment, if the propagation environment is so bad that the reception of the header field also fails, the communication is performed in the ACK mode using the ACK signal, and the reception of the data field fails. For example, by performing communication in the NACK mode or the mixed mode using the NACK signal, it is possible to improve the transmission efficiency while reducing the undetected reception error.</p><p>When the 1st and 2nd wireless devices 1 and 2 send and receive multi-data signals that aggregate subframes, and if even one of them fails to receive the MAC sub header, the BA includes information indicating that fact. Send a signal or NBA signal. The first wireless device 1 that has received the BA signal or the NBA signal including the information indicating that the reception of the MAC sub header has failed switches the response mode to the ACK mode and performs communication. As a result, the first wireless device 1 can quickly switch to the ACK mode even if the propagation environment deteriorates while receiving the multi-data signal.</p>

<p>Example 4 according to the present invention will be described with reference to FIG. The packet configuration of the data signal exchanged by the wireless system of this embodiment is the same as that shown in FIG. Further, the first and second wireless devices 1 and 2 of this embodiment have the same configuration as that of FIG. 7 except for the operation of each part.</p><p>FIG. 13 is a diagram showing communication between the first and second wireless devices 1 and 2 after the connection is established by the first wireless device 1 as a transmitter and the second wireless device 2 as a receiver. Since it is the same as FIG. 2 until the first wireless device 1 transmits the data signal D103, the description thereof will be omitted.</p><p>The second wireless device 2 receives the data signal D103. The second wireless device 2 determines whether or not the header field and the data field have been successfully received. In the example of FIG. 13, the header field and the data field have been successfully received. The second wireless device 2 stores the divided data DATA3 included in the data field in the reception buffer B2. At this time, the second wireless device 2 determines from the reception result of the header field that the SN of the data signal D103 is 3, which is not continuous with the SN (= 1) of the previously received data signal D101. That is, it is determined that there is a data signal D102 that has not been received between the data signal D101 received last time and the data signal D103 received this time. When the second wireless device 2 determines that there is data that has not been received, the second wireless device 2 notifies the first wireless device 1 to that effect. In FIG. 13, since the data signal D102 is not received, the second wireless device 2 returns the NACK signal A132 including the information indicating SN = 2 of the data signal D102 to the first wireless device 1.</p><p>The first wireless device 1 receives the NACK signal A132. Since the NACK signal A132 contains information indicating SN = 2, the first wireless device 1 retransmits the data signal D102 having SN = 2. Further, since the NACK signal A132 does not include SN = 3, the first wireless device 1 determines that the second wireless device 2 has succeeded in receiving the data signal D103. In FIG. 13, the first wireless device 1 retransmits the data signal D102 including the NACK request.</p><p>The second wireless device 2 receives the data signal D102. The second wireless device 2 determines whether or not the header field and the data field have been successfully received. In the example of FIG. 13, the header field and the data field have been successfully received. The second wireless device 2 stores the divided data DATA2 included in the data field in the reception buffer B2. Further, the second wireless device 2 analyzes the header field and determines that the first wireless device 1 is requesting the NACK signal. Since the data signal D102 has been successfully received, the second wireless device 2 does not return the response signal.</p><p>If the first wireless device 1 does not receive the response signal for a certain period of time after retransmitting the data signal D102, the NACK signal is not returned even after a certain period of time, so it is determined that the data signal D102 has been successfully transmitted. The first wireless device 1 transmits the data signal D134.</p><p> As described above, the second wireless device 2 of the present embodiment compares whether or not the SN of the data signal that has been successfully received and the SN of the data signal that has been successfully received immediately before the SN are continuous. If the compared SNs are not continuous and there is a data signal that failed to be received between the SN of the data signal that was successfully received and the SN of the data signal that was successfully received immediately before that, the second radio The device 2 includes the SN of the data signal that failed to be received in the NACK signal and returns it to the first wireless device 1. In the second wireless device 2, instead of the SN of the data signal that failed to be received, the SN of the data signal that was finally successfully received, that is, the above-mentioned "SN of the data signal that was successfully received immediately before that" ( In FIG. 13, j may transmit SN = 1) including the NACK signal. As a result, even if the propagation environment deteriorates and the reception of the header field fails, the undetected reception error can be reduced, and the data signal can be reliably retransmitted. In particular, even when the second wireless device 2 cannot receive the data signal D102 itself and it is not even known that the data signal D102 exists, the first wireless device 1 can reduce the undetected reception error.</p><p>(Modification example 3) In the fourth embodiment, when the data signal D102 that has failed to be received exists, the response signal of the data signal D103 transmitted by the second wireless device 2 is an NACK signal. In this modification, the type of response signal is determined depending on whether or not the second wireless device 2 desires to retransmit the data signal D103. Other than that, it is the same as in Example 4.</p><p> First, a case where the second wireless device 2 succeeds in receiving the header field but fails in receiving the data field will be described. In this case, since the data signal D103 needs to be retransmitted, the second radio device 2 transmits the NACK signal regardless of the type of response request described in the header field. The NACK signal includes the SN (= 2) of the unreceived data signal D102 as in the fourth embodiment.</p><p> When the first wireless device 1 receives the NACK signal including SN = 2, it retransmits the data signal D102, and if the data signal D102 is successfully retransmitted, the first wireless device 1 retransmits the data signal D103.</p><p> Next, a case where the second wireless device 2 succeeds in receiving the header field and the data field will be described. In this case, since it is not necessary to retransmit the data signal D103, the second wireless device 2 transmits the ACK signal regardless of the type of response request described in the header field. The ACK signal includes the SN (= 2) of the unreceived data signal D102.</p><p> When the first wireless device 1 receives the NACK signal including SN = 2, it retransmits the data signal D102, but does not retransmit the data signal D102, and transmits the next data signal, the data signal D134.</p><p> The present invention is not limited to the above-described embodiment as it is, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by an appropriate combination of the plurality of components disclosed in the above-described embodiment. For example, some components may be removed from all the components shown in the embodiments. In addition, components across different embodiments may be combined as appropriate.</p>

1,2,3 radio equipment, 10 antennas, 20 radios, 31 modulations, 32 demodulations 41 transmitters, 42 receivers, 43 response mode management, 44 response signal controls, 45 receive buffers