JP4789071B2 - Wireless transmission device - Google Patents

Description

  The present invention relates to a radio transmission apparatus, and more particularly to a radio transmission apparatus that multiplexes a frame format different from a MAC (Media Access Control) frame and transmits the frame format to an opposite station.

  2. Description of the Related Art Conventionally, in a wireless transmission device that transmits a LAN (Local Area Network) signal, a layer 2 switch / layer 3 switch / MAC provided with an overflow inside and outside the device due to a difference between the transmission capacity of the user network and the wireless transmission capacity In many cases, this problem is avoided by using only the flow control function conforming to IEEE 802.3 by the LAN device.

  Here, the transmission capacity of the user network is one of 10 Mbps, 100 Mbps, and 1000 Mbps defined by IEEE 802.3, and there is a case where the transmission capacity differs between the opposite stations. On the other hand, the wireless transmission capacity is determined from the main signal transmission capacity, the radio frequency, and the modulation / demodulation method, and is designed so that various main signals can be transmitted by the same wireless apparatus. Therefore, it is generally different from the LAN transmission capacity.

  However, with only the flow control conforming to IEEE 802.3 by the LAN device, there is a possibility that an overflow occurs in the main signal reception memory due to the propagation delay of the flow control frame conforming to IEEE 802.3 generated in the memory inside the wireless transmission apparatus. As a countermeasure, the layer 2 switch / layer 3 switch / MAC is equipped with a large-sized memory to increase the tolerance for the propagation delay of the control frame, or to lower the flow control trigger threshold of IEEE 802.3 compliant. It was necessary to cancel the propagation delay of the wireless transmission device by speeding up the activation. As a result, there has been a problem that the price of the device itself is increased due to an increase in the memory size and the transmission efficiency is decreased due to frequent flow control.

  In addition, when the transmission capacities between the user networks facing each other via the wireless transmission apparatus are different, the layer 2 switch / layer 3 switch / MAC flow control frame is used to absorb the transmission capacity difference between the facing, The same problem as described above may occur due to the propagation delay generated in the memory of the wireless transmission device. Furthermore, in the flow control, band limitation is applied in accordance with a low transmission capacity. Therefore, when the transmission capacity of the user network is lower than the wireless transmission capacity, many pause frames are transmitted instead of the main signal. There is a problem that the bandwidth of the transmission path is wasted.

  An example of a conventional wireless transmission apparatus will be described with reference to FIG. In FIG. 1, since the configuration of the terminal station X (x10) and the terminal station Y (y10) is the same, the description will be made with a focus on the terminal station X (x10).

  In the terminal station X (x10), the plurality of telephone terminals 1 to 4 (x1 to x4) convert the analog voice signal and various control signals into signals obtained by digital conversion, thereby converting the terminal equipment into telephone terminal data (x101 to x401). Output to (x5). Similarly, the call terminals 1 to 4 (x1 to x4) convert the digital signals of the call data 1 to 4 (x101 to x401) from the terminal device (x5) into analog signals and output them as voices. The call terminal is controlled based on the various control signals generated from.

  The terminal equipment (x5) multiplexes the call data 1 to 4 (x101 to x401) from the call terminals 1 to 4 (x1 to x4), and multiplexes a plurality of fixed band signals Ch. 1-Ch. n (x501 to x504) is output to the automatic band switching control device (x7). Similarly, the terminal station device (x5) receives a plurality of fixed band signals Ch.1 from the automatic band switching control device (x7). 1-Cn. Call data (x101 to x401) obtained by separating n (x501 to x504) is output to the call terminals 1 to 4 (x1 to x4).

  The layer 3 switch (x6) receives a plurality of LAN signals (x1001 to x1002) from the 100BASE-T network, performs route switching based on the IP address and flow control, and sends the LAN signal addressed to the opposite station to the variable band signal. (X601) is output to the automatic band switching enforcement device (x7). Similarly, the layer 3 switch (x6) receives the variable band signal (x601) from the band automatic switching control device (x7), performs route switching based on the IP address and flow control, and performs a plurality of LAN signals (x1001). To x1002) are output to the 100BASE-T network.

  The automatic band switching control device (x7) multiplexes the fixed band signal (x501 to x504) from the terminal station device (x5) and the variable band signal (x601) from the layer 3 switch (x6) to obtain the STM transmission technology. The channel-switched signal Ch. 1-Ch. n (x701 to x704) is output to the transmission / reception device (x8). Similarly, the automatic band switching control device (x7) receives the signal Ch. After the band switching from the transmission / reception device (x8). 1-Ch. n (x701 to 704), the fixed band signal Ch. 1-Ch. n (x501 to x504) and variable band signal (x601) are output to the terminal device (x5) and the layer 3 switch (x6), respectively.

  The transmission / reception device (x8) performs radio modulation on the post-band switching signals (x701 to x704) from the automatic band switching control device (x7), and transmits the transmission signal (801) to the terminal station Y (y10) of the opposite station. Output. Similarly, the wireless signal (801) is wirelessly demodulated and the post-switching band signals (x701 to x704) are output.

  In the prior art described above, the transmission band of the wireless section is set to the signal Ch. After switching the band for each channel based on the STM transmission technique. 1-Ch. n (x701 to x704), and after switching the signal Ch. to the fixed band signal (x501 to x504) and the variable band signal (x601) according to the usage status of the communication terminals 1 to 4 (x1 to x4). 1-Ch. By changing the allocation amount of n (x701 to x704), it is possible to dynamically change the bandwidth usage of the call terminals 1 to 4 (x1 to x4) and the 100BASE-T network.

  However, in the prior art, only the flow control conforming to IEEE802.3 by the layer 3 switch (x6, y6) is used in the flow control between the terminal BASE X (x10) and the terminal station Y (y10) between the 100BASE-T networks. Therefore, flow control is not in time due to the propagation delay of the control frame generated in the automatic band switching control device (x7, y7) and the transmission / reception device (x8, y8), and overflow occurs in the reception memory 1 (x5, y5). As a solution to the above problem, if the amount of internal memory is increased or the flow control trigger threshold is lowered in the layer 3 switch (x6, y6), the transmission increases due to an increase in the device price due to the increase in memory or the occurrence of many control frames. There was a problem of reduced efficiency.

Japanese Patent Laid-Open No. 2004-207776 (Patent Document 1) discloses a transmission band automatic switching control device.
In this prior art, when the local station automatic band switching control apparatus tries to transmit 100BASE-TX data, it monitors the unused ports of the CH1-CH7 input ports, and transmits the unused port information to the radio and the fixed band transmission. Notification is sent to the automatic bandwidth switching control device on the game side via the route. Then, the automatic bandwidth switching control device on the own station side and the opposite side changes the allocation of the CH1-CH7 fixed band communication port in synchronization with 100BASE-TX data transmission / reception according to the free port information, and connectionless communication To expand the transmission bandwidth.

Japanese Patent Laid-Open No. 2004-289716 (Patent Document 2) discloses a data communication system and a flow control method.
In this prior art, in a data communication system including a plurality of transmission apparatuses having a buffer memory for temporarily storing frame-structured data and transmitting / receiving the data, and a flow control method between the transmission apparatuses, the transmission apparatus includes: Round trip for measuring the round trip transmission delay time between the pause transmission device and the opposite transmission device by sending and receiving the time measurement frame and the pause transmission device for sending a pause frame to the opposite transmission device when the amount of stored data reaches the threshold A transmission delay measurement unit and a threshold value determination unit are provided, and the threshold value of the buffer memory is determined according to the round-trip transmission delay time between the transmission devices and the connection transmission speed between the transmission devices.

Japanese Patent Laying-Open No. 2004-343641 (Patent Document 3) discloses a radio base station apparatus and a data transfer control method.
In this prior art, the buffer temporarily stores data of the data frame signal transferred from the RNC device. The accumulation amount measuring unit measures the accumulation amount of the data accumulated in the buffer. The parameter setting unit sets a buffer size, a first threshold value, a second threshold value, a credit value, an interval value, and a repetition period value. The determination unit determines whether the accumulation amount increases and exceeds the first threshold value or the second threshold value, or whether the accumulation amount decreases and falls below the first threshold value or the second threshold value. Based on the determination result, the CACF signal generation unit generates a CACF signal using a combination of a credit value, an interval value, and a repetition period value such that the accumulated amount is within a range larger than “0” and less than or equal to the buffer size. . The transmission unit transmits a CACF signal to the RNC device.

Japanese Patent Laying-Open No. 2005-260839 (Patent Document 4) discloses a frame transfer apparatus.
In this prior art, the flow control detection unit detects a pause frame from the frame input from the port, and the congestion prediction unit predicts that congestion will occur from the transmission stop time in the pause frame, and then sends the frame to the output queue. Output prohibition notification and transfer prohibition notification for prohibiting the accumulation of data, and the frame analysis unit releases the frame buffer address if the input frame is a frame to a port that has received the transfer prohibition notification. And discard the frame.

Japanese Patent Laying-Open No. 2006-129495 (Patent Document 5) discloses a time critical information transmission method in a synchronous Ethernet (registered trademark) system.
In this prior art, as a first stage process, a time critical event is detected and the current transmission period is confirmed. As a result of the confirmation, if the current transmission period is a synchronization frame period, time critical control information is generated, and the generated time critical control information is generated in the first sub-synchronization frame after detecting the time critical event. Is inserted and transmitted. On the other hand, if the current transmission period is an asynchronous frame period as a result of the confirmation in the first stage, a control frame including time critical control information is generated and transmitted.

Japanese Laid-Open Patent Publication No. 06-079883 (Patent Document 6) discloses a network system.
In the node of this network system, a frame received at the physical layer interface is stored in a reception buffer. The buffer usage monitoring circuit checks the number of frames in the reception buffer every time a frame is received, and generates a buffer full signal if the number of checked frames is greater than a preset number of frames. When this buffer full signal is received, the protocol controller sets a transmission stop frame in the transmission buffer and instructs the physical layer interface to transmit. Further, when the number of frames in the reception buffer becomes equal to or less than the predetermined number of frames, a buffer empty signal is generated, and a transmission start frame is transmitted according to the buffer empty signal.

JP 2004-207776 A JP 2004-289716 A Japanese Patent Laid-Open No. 2004-343641 JP 2005-260839 A JP 2006-129495 A Japanese Patent Application Laid-Open No. 06-079883

An object of the present invention is to provide a wireless transmission device that multiplexes a LAN signal of a user network into a frame format different from an IEEE 802.3-compliant MAC frame (hereinafter referred to as a MAC frame) and transmits the multiplexed signal to an opposite station.
Another object of the present invention is to provide a wireless transmission apparatus that performs control (flow control) that automatically optimizes the transmission capacity of a LAN signal transmitted to a wireless transmission path in accordance with the amount of traffic of a user network. .
Still another object of the present invention is to provide a wireless transmission device that enables transmission of other signals using an unused wireless transmission path band.

  In the following, means for solving the problem will be described using the numbers used in [Best Mode for Carrying Out the Invention] in parentheses. These numbers are added to clarify the correspondence between the description of [Claims] and [Best Mode for Carrying Out the Invention]. However, these numbers should not be used to interpret the technical scope of the invention described in [Claims].

  The wireless transmission device (a10, b10) of the present invention is a wireless transmission device provided between the wireless transmission path (20) and the user network, and uses a frame different from the MAC frame for the wireless transmission path (20). A transmission circuit (a12, b12) for transmitting a control signal, a reception circuit (a13, b13) for receiving another control signal using a frame different from the MAC frame from the wireless transmission path (20), and a transmission circuit (a12) , B12) and the receiving circuit (a13, b13), and without passing through the signal speed conversion memory (a1, a4, a7, a8, b1, b4, b7, b8) in the apparatus, the previous stage (a2, a3 , A5, a6, a9, b2, b3, b5, b6, b9), the control frame including the control signal is transmitted / received and detected. Comprising speed conversion section and transmitting the multiplexed signals of the auxiliary network to payload pause frames to be transmitted instead of the beam and (a11, b11).

  The speed conversion unit (a11, b11) includes a first transmission memory (a1, b1) that stores transmission LAN signals (a100, b100) from the user network at the signal speed of the user network, and frame switching control signals (a302, b302). ) And the transmission signal changeover switch (a3, b3) and the frame switching control signal (a302, b302) from the transmission signal changeover switch (a3, b3). 20) The transmission LAN signal (a100, b100) is read from the first transmission memory (a1, b1) at the signal speed on the side, the speed conversion is performed, and the transmission main signal frame (a201) is multiplexed into a frame format different from the MAC frame. , B201) to the first frame circuit (a3, b3) to be output to the transmission signal selector switch (a3, b3). 2, b2), a second transmission memory (a4, b4) for receiving transmission auxiliary signals (a400, b400) from the auxiliary network and storing them at the signal speed of the auxiliary network, and a second transmission memory (a4, b4) Control frame generation circuit (a5, b5) that reads out the transmission auxiliary signal (a400, b400) from the signal at the signal speed on the wireless transmission line (20) side, multiplexes it into the pause frame, and outputs it to the transmission signal changeover switch (a3, b3) If the received frame (a1301, b1301) from the receiving circuit (a13, b13) is a control frame, it is determined whether it is a transmission stop frame or a transmission restart frame, and the result is determined as a pause frame selection control signal (a601). , B601) and control frame detection circuits (a6, b6) for outputting to transmission signal changeover switches (a3, b3). .

  When the control frame is selected in accordance with the frame switching control signals (a302, b302) from the transmission signal changeover switches (a3, b3), the control frame generation circuit (a5, b5) is a pause frame / transmission stop frame / transmission. One of the restart frames is output to the transmission signal changeover switches (a3, b3) as transmission control signal frames (a501, b501).

  The transmission signal selector switch (a3, b3) is configured to transmit the transmission control signal frame (a501, b501) from the control frame generation circuit (a5, b5) and the transmission main signal frame (a201, b2) from the first frame circuit (a2, b2). b201) is selected and output to the transmission circuit (a12, b12) as a transmission frame (a301, b301) after switching.

  The wireless transmission device (a10, b10) of the present invention reads the written MAC frame at the signal speed on the user network side and outputs it to the user network as a received LAN signal (a701, b701). A second reception memory (a8, b8) that reads out the written transmission auxiliary signals (a400, b400) at the signal speed of the auxiliary network and outputs them as reception auxiliary signals (a801, b801), and reception circuits (a13, b13). ) Received frame (a1301, b1301) from the second frame circuit (a9) that separates the MAC frame and writes it to the first reception memory (a7, b7) at the signal speed of the wireless transmission path (20). , B9).

  The control frame detection circuits (a6, b6) receive frames (a1301, b1301) from the reception circuits (a13, b13) when the reception frames (a1301, b1301) from the reception circuits (a13, b13) are pause frames. The transmission auxiliary signal (a400, b400) is separated from the second reception memory (a8, b8) at the signal speed of the wireless transmission path (20).

  The first reception memory (a7, b7) monitors its own memory usage, determines whether the current memory usage is greater than or equal to a preset upper limit set value or less than a lower limit set value, and the result is the memory usage. The notification signal (a702, b702) is output to the transmission signal selector switch (a3, b3).

  The transmission signal selector switch (a3, b3) is a pause frame selection control signal (a601, b601) from the control frame detection circuit (a6, b6) and a memory usage notification signal (a7, b7) from the first reception memory (a7, b7). a702, b702), one of the main signal frame and the control frame is selected, the type of the control frame is selected, and the result is used as a frame switching control signal (a302, b302). The data is output to the generation circuit (a5, b5) and the first frame circuit (a2, b2).

  The transmission signal selector switch (a3, b3) includes an operation state determination unit (a3-1) that performs state transition using the pause frame selection control signals (a601, b601) from the control frame detection circuits (a6, b6), Based on the state notification signal (a3-101) from the operation state determination unit (a3-1) and the memory usage notification signals (a702, b702) (a702, b702) from the first reception memories (a7, b7), A frame selection logic unit (a3-2) that selects a frame according to the frame switching logic and outputs the result to the control frame generation circuit (a5, b5) and the first frame circuit (a2, b2) as a frame switching control signal (a302, b302). ) And the main signal frame according to the frame switching control signal (a302, b302) from the frame selection logic unit (a3-2) When transmission main signal frames (a201, b201) from one frame circuit (a2, b2) are selected and a control frame is selected, transmission control signal frames (a501, b501) from control frame generation circuits (a5, b5) are selected. And a selector (a3-3) that outputs to the transmission circuit (a12, b12) as a transmission frame (a301, b301) after switching.

  When the control frame detection circuit (a6, b6) detects the transmission stop frame, the operation state determination unit (a3-1) transitions from the normal state to the sleep state.

  When the control frame detection circuit (a6, b6) detects the transmission restart frame, the operation state determination unit (a3-1) transitions from the sleep state to the normal state, and uses the result as a state notification signal (a3-101) to frame The data is output to the selection logic unit (a3-2).

The first effect is that, in the user network opposed via the wireless transmission device, when the individual transmission capacities are different, the memory increase of the LAN device such as the layer 2 switch / layer 3 switch / MAC or the flow control conforming to IEEE 802.3 is achieved. It is possible to absorb the transmission capacity difference between user networks without special measures such as lowering the activation threshold. The reason is that in a wireless transmission device that multiplexes and transmits a LAN signal in a frame different from a MAC frame, the wireless transmission device transmits and receives control signals in a frame different from the MAC frame based on the amount of reception memory used. Flow control between the user network and the wireless transmission path without being affected by propagation delay in the frame by controlling the flow between the user network and the wireless transmission path. This is because the flow control control signal can be transmitted and received.
The second effect is that the transmission capacity used by the user network on the wireless transmission path is sacrificed when the transmission capacity of the user network is lower than that of the wireless transmission path or when the transmission capacity between the opposing user networks is different. Without being able to transmit the auxiliary network signal. The reason is that the auxiliary network signal is multiplexed and transmitted on the payload of a pause frame used for original flow control. In the wireless transmission device of the present invention, in order to limit the wireless transmission capacity, a pause frame is transmitted instead of the main signal frame. Therefore, it is possible to transmit the auxiliary network signal without sacrificing the wireless transmission path band used by the user network.

  A feature of the present invention is that, in a wireless transmission device that multiplexes a LAN signal of a user network into a frame format different from an IEEE802.3-compliant MAC frame (hereinafter referred to as a MAC frame) and transmits the multiplexed signal to an opposite station, the traffic amount of the user network By performing control (flow control) that automatically optimizes the transmission capacity of the LAN signal sent to the wireless transmission path according to the transmission, other signals can be transmitted using the unused wireless transmission path band. It is to be.

A first embodiment of the present invention will be described below with reference to the accompanying drawings.
FIG. 2 is a block diagram showing an embodiment of the wireless transmission apparatus of the present invention.
The wireless transmission device of the present invention includes a terminal station A (a10) and a terminal station B (b10). Here, the internal configurations of the terminal station A (a10) and the terminal station B (b10) are the same. However, actually, the present invention is not limited to the case where they are completely the same. Only the configuration related to the present invention may be the same. The terminal station A (a10) and the terminal station B (b10) are connected by a wireless transmission path (20).

  The terminal station A (a10) includes a speed conversion unit (a11), a transmission circuit (a12), and a reception circuit (a13). The speed converter (a11) includes a transmission memory 1 (a1), a frame circuit 1 (a2), a transmission signal changeover switch (a3), a transmission memory 2 (a4), a control frame generation circuit (a5), A control frame detection circuit (a6), a reception memory 1 (a7), a reception memory 2 (a8), and a frame circuit 2 (a9) are provided.

  Similarly, the terminal station B (b10) includes a speed conversion unit (b11), a transmission circuit (b12), and a reception circuit (b13). The speed converter (b11) includes a transmission memory 1 (b1), a frame circuit 1 (b2), a transmission signal changeover switch (b3), a transmission memory 2 (b4), a control frame generation circuit (b5), A control frame detection circuit (b6), a reception memory 1 (b7), a reception memory 2 (b8), and a frame circuit 2 (b9) are provided.

  The transmission memory 1 (a1, b1) in the speed conversion unit (a11, b11) writes the transmission LAN signal (a100, b100) from the user network into the memory at the signal speed of the user network. The frame circuit 1 (a2, b2) transmits at the signal speed on the wireless transmission path side when the main signal frame is selected according to the frame switching control signals (a302, b302) from the transmission signal switching switches (a3, b3). After the transmission LAN signals (a100, b100) are read from the memory 1 (a1, b1) and the speed conversion is performed, the transmission signal is switched as a transmission main signal frame (a201, b201) by multiplexing to a frame format different from the MAC frame. Output to switches (a3, b3).

  The transmission memory 2 (a4, b4) receives the transmission auxiliary signal (a400, b400) from the auxiliary network A, and writes it in the memory at the signal speed of the auxiliary network A. The control frame generation circuit (a5, b5) reads the auxiliary signal from the transmission memory 2 (a4, b4) at the signal speed on the wireless transmission path side, and then multiplexes it with the pause frame to the transmission signal changeover switch (a3, b3). Output.

  The control frame generation circuit (a5, b5), when the control frame is selected according to the frame switching control signal (a302, b302) from the transmission signal changeover switch (a3, b3), is a pause frame / transmission stop frame. Any one of the transmission restart frames is output to the transmission signal changeover switches (a3, b3) as transmission control signal frames (a501, b501).

  The transmission signal selector switch (a3, b3) is a pause frame selection control signal (a601, b601) from the control frame detection circuit (a6, b6) and a memory usage amount notification signal (a7, b7) from the reception memory 1 (a7, b7). The control frame generation circuit described above selects either the main signal frame or the control frame based on a702, b702), selects the type of the control frame, and uses the result as the frame switching control signal (a302, b302). (A5, b5) and the frame circuit 1 (a2, b2). Further, either one of the transmission control signal frame (a501, b501) from the control frame generation circuit (a5, b5) and the transmission main signal frame (a201, b201) from the frame circuit 1 (a2, b2) is selected. Then, it is output to the transmission circuit (a12, b12) as a transmission frame (a301, b301) after switching.

  The transmission circuit (a12, b12) multiplexes the post-switching transmission frame (a301, b301) from the transmission signal changeover switch (a3, b3) into the wireless transmission path frame, and from the physical interface of the speed conversion unit (a11, b11). After conversion to the physical interface of the wireless transmission path (20), the transmission transmission signals (a1201, b1201) are output to the wireless transmission path (20).

  On the other hand, the receiving circuit (a13, b13) converts the received transmission signal (a1300, b1300) from the wireless transmission path (20) into a physical interface inside the speed conversion unit (a11, b11), and then receives it from the wireless transmission path frame. The frames (a1301, b1301) are separated and output to the frame circuit 2 (a9, b9) and the detection circuit (a6, b6).

  When the reception frame (a1301, b1301) from the reception circuit (a13, b13) is the main signal frame, the frame circuit 2 (a9, b9) separates the MAC frame and transmits the wireless transmission path to the reception memory 1 (a7, b7). Write at a signal speed of. In the case of a control frame, the received frame (a1301, b1301) is discarded. The reception memory 1 (a7, b7) reads the written MAC frame at the signal speed on the user network side and outputs it to the user network as reception LAN signals (a701, b701). The reception memory 1 (a7, b7) monitors its own memory usage, determines whether the current memory usage is greater than or equal to a preset upper limit set value or less than a lower limit set value, and uses the result in memory. The amount notification signal (a702, b702) is output to the transmission signal selector switch (a3, b3).

  When the received frame (a1301, b1301) from the receiving circuit (a13, b13) is a control frame, the control frame detection circuit (a6, b6) determines whether the frame is a transmission stop frame or a transmission restart frame. Are output to the transmission signal changeover switches (a3, b3) as pause frame selection control signals (a601, b601). When the reception frames (a1301, b1301) from the reception circuits (a13, b13) are pause frames, the auxiliary signal is separated from the reception frames (a1301, b1301), and the reception memory 2 ( Write to a8, b8). The reception memory 2 (a8, b8) reads the written auxiliary signal at the signal speed of the auxiliary network A and outputs it as reception auxiliary signals (a801, b801). If a frame other than the above is detected, the received frame (a1301, b1301) is discarded.

  Next, the operation of the wireless transmission device will be described using the block diagram shown in FIG. Here, since the internal configurations of the terminal station A (a10) and the terminal station B (b10) in FIG. 2 are the same, the terminal station A (a10) will be described. The same applies to the terminal station B (b10).

  First, the transmission memory 1 (a1) writes the transmission LAN signal (a100) from the user network A having the transmission capacity defined by IEEE 802.3 into the memory at the signal speed of the user network A, and at the speed on the wireless transmission path side. Signal speed conversion is performed by reading the transmission LAN signal (a100). After that, the frame circuit 1 (a2) multiplexes the speed-converted MAC frame into a frame signal different from the MAC frame, and outputs it to the transmission signal selector switch (a3) as the main signal frame (a201). However, the series of operations described above are valid only when the transmission signal changeover switch (a3) selects the main signal frame according to the frame changeover control signal (a302) from the transmission signal changeover switch (a3), and the control frame is selected. If this happens, the above series of operations is stopped. Here, the frame different from the MAC frame is composed of an overhead (F1) and a payload (F2) as shown in the main signal frame of FIG. 3, and various control signals of the frame are multiplexed on the overhead (F1), and the payload (F2 ) Multiplexes MAC frames. The overhead (F1) is a fixed length and the payload (F2) is a variable length.

  The transmission memory 2 (a4) receives the auxiliary signal from the transmission auxiliary signal (a400) from the auxiliary network A, and writes it in the memory at the signal speed of the auxiliary network A. The control frame generation circuit (a5) reads the auxiliary signal from the transmission memory 2 (a4) at the signal speed on the wireless transmission path side, multiplexes it with the pause frame, and outputs it to the transmission signal changeover switch (a3).

  The control frame generation circuit (a5) generates any one of a pause frame, a transmission stop frame, and a transmission restart frame in accordance with the frame switching control signal (a302) from the transmission signal changeover switch (a3). a501), it outputs to the transmission signal changeover switch (a3). The series of operations is valid only when the transmission signal selector switch (a3) selects the control frame, and when the main signal frame is selected, the series of operations is stopped. Here, as shown in FIG. 3, the control frame includes only the control signal (F3) except for the pause frame. The pause frame includes a control signal (F6-1) and a payload (F6-2). The two types of control frames are distinguished from each other by a fixed-length control signal (F3, F6-1), and in the pause frame, a variable-length payload (F6-2) is a signal from the auxiliary network. Is multiplexed.

FIG. 4 shows a flowchart of the operation of the wireless transmission device.
(1) Step S101
It is confirmed whether the transmission signal selector switch (a3) has selected the main signal frame. When the transmission signal selector switch (a3) does not select the main signal frame, that is, when the control frame is selected, the operation is stopped.
(2) Step S102
When the transmission signal selector switch (a3) selects the main signal frame, the transmission memory 1 (a1) transmits the transmission LAN signal (a100) from the user network A having the transmission capacity defined by IEEE 802.3 to the user network A. The signal speed is converted by writing to the memory at a signal speed of 1 and reading the transmission LAN signal (a100) at the speed of the wireless transmission path.
(3) Step S103
The frame circuit 1 (a2) multiplexes the speed-converted MAC frame into a frame signal different from the MAC frame, and outputs it to the transmission signal changeover switch (a3) as a main signal frame (a201).
(4) Step S104
The transmission memory 2 (a4) receives the transmission auxiliary signal (a400) from the auxiliary network A and writes it in the memory at the signal speed of the auxiliary network A.
(5) Step S105
The control frame generation circuit (a5) reads the transmission auxiliary signal (a400) from the transmission memory 2 (a4) at the signal speed on the wireless transmission path side, multiplexes it with the pause frame, and outputs it to the transmission signal changeover switch (a3). .
(6) Step S106
The control frame generation circuit (a5) generates any one of a pause frame, a transmission stop frame, and a transmission restart frame in accordance with the frame switching control signal (a302) from the transmission signal changeover switch (a3). a501), it outputs to the transmission signal changeover switch (a3).

Next, the operation of the transmission signal selector switch (a3) will be described with reference to FIGS.
As shown in FIG. 5, the transmission signal selector switch (a3) includes an operation state determination unit (a3-1), a frame selection logic unit (a3-2), and a selector (a3-3). The transmission signal switch (b3) is the same as the transmission signal switch (a3).

  In FIG. 5, the operation state determination unit (a3-1) inside the transmission signal changeover switch (a3) performs the state transition of FIG. 6 using the pause frame selection control signal (a601) from the control frame detection circuit (a6). Do. In the state transition diagram of FIG. 6, when the control frame detection circuit (a6) of FIG. 2 detects a transmission stop frame, the normal state (C1) transitions to the pause state (C2). When a transmission resumption frame is detected, the state transits from the pause state (C2) to the normal state (C1), and the result is output to the frame selection logic unit (a3-2) as a state notification signal (a3-101).

  The frame selection logic unit (a3-2) in FIG. 5 receives a state notification signal (a3-101) from the operation state determination unit (a3-1) and a memory usage notification signal from the reception memory 1 (a7) in FIG. Based on (a702), a frame is selected according to the frame switching logic of FIG. 7, and the result is output as a frame switching control signal (a302) to the control frame generation circuit (a5) and the frame circuit 1 (a2).

Here, the frame switching logic of FIG. 7 will be described. The frame switching logic in FIG. 7 performs the following processing.
(1) Step L1
The frame selection logic unit (a3-2) acquires the memory usage notification signal (a702) in FIG. 2 and the state notification signal (a3-101) in FIG.
(2) Step L2
Next, the frame selection logic unit (a3-2) evaluates the memory usage of the reception memory 1 (a7) in FIG. 2 based on the memory usage notification signal (a702). Here, it is confirmed whether the memory usage is equal to or more than the upper limit setting.
(3) Step L3
The frame selection logic unit (a3-2) selects a transmission stop frame for the frame switching control signal (a302) if the memory usage of the memory is equal to or greater than the upper limit setting.
(4) Step L4
Further, the frame selection logic unit (a3-2) evaluates the memory usage of the reception memory 1 (a7) in FIG. 2 based on the memory usage notification signal (a702). Here, it is confirmed whether the memory usage is below the lower limit set value.
(5) Step L5
The frame selection logic unit (a3-2) selects a transmission restart frame as the frame switching control signal (a302) if the memory usage is equal to or less than the lower limit set value.
(6) Step L6
When the memory usage is neither the upper limit set value nor the lower limit set value, the frame selection logic unit (a3-2) operates from the status notification signal (a3-101) to the operation status determination unit (a3-1). Evaluate the operating state of
(7) Step L7
If the operation state of the operation state determination unit (a3-1) is a dormant state, the frame selection logic unit (a3-2) selects a dormant frame for the frame switching control signal (a302).
(8) Step L8
If the operation state of the operation state determination unit (a3-1) is the normal state, the frame selection logic unit (a3-2) selects the main signal frame as the frame switching control signal (a302).

  The selector (a3-3) in FIG. 5 follows the frame switching control signal (a302) from the frame selection logic unit (a3-2), and selects the main signal frame from the frame circuit 1 (a2) in FIG. When the transmission main signal frame (a201) is selected and the control frame is selected, the transmission control signal frame (a501) from the control frame generation circuit (a5) is selected, and the transmission circuit (a12) is selected as the transmission frame after switching (a301). ).

  The transmission circuit (a12) in FIG. 2 multiplexes the post-switching transmission frame (a301) from the transmission signal changeover switch (a3) into the wireless transmission path frame, and then transmits the wireless transmission path from the physical interface in the speed conversion unit (a11). The data is converted into the physical interface (20) and output as a transmission transmission signal (a1201) to the wireless transmission path (20) having a transmission capacity different from that of the user networks A and B. Here, as shown in FIG. 3, the wireless transmission path frame is composed of an overhead (F4) and a payload (F5). In the overhead (F4), various control signals in the wireless transmission path section are multiplexed and the payload (F5) is multiplexed. Multiplex main signal frame or control signal frame. The overhead (F4) is a fixed length and the payload (F5) is a variable length. As described above, in the wireless transmission device of the present invention, the control frame for flow control is generated at the subsequent stage of the transmission memory 1 (a1) for speed conversion, so that it is not affected by the transmission delay due to the memory in the device. The control frame can be transmitted.

  On the other hand, the receiving circuit (a13) receives the received transmission signal (a1300) received from the terminal station B (b10) of the opposite station via the wireless transmission path (20) having a transmission capacity different from that of the user network A. After converting the physical interface signal of (20) into the physical interface signal in the speed converter (a11), the received frame (a1301) is separated from the radio transmission path frame and output to the frame circuit 2 (a9).

  When the reception frame (a1301) from the reception circuit (a13) is a control frame, the frame circuit 2 (a9) discards the reception frame (a1301) for processing by the control frame detection circuit (a6). When the reception frame (a1301) is a main signal frame, the MAC frame is separated and written to the reception memory 1 (a7) at the signal speed of the wireless transmission path (20). The reception memory 1 (a7) reads out the written MAC frame at the signal speed of the user network A, converts the signal speed between the user network A and the wireless transmission path, and then outputs it as a reception LAN signal (a701). To do. At this time, the reception memory 1 (a7) determines whether the current memory usage is greater than or equal to the preset upper limit set value or less than the lower limit set value, and the result is used as the memory usage notification signal (a702). To the transmitted signal changeover switch (a3).

  The control frame detection circuit (a6) determines the type when the reception frame (a1301) from the reception circuit (a13) is a control signal frame. When a transmission stop frame / transmission resumption frame is detected, the result is output to the transmission signal switch (a3) described above as a pause frame selection control signal (a601). When a pause frame is detected, the auxiliary signal is separated and written to the reception memory 2 (a8) at the signal speed of the wireless transmission path (20). The reception memory 2 (a8) is the signal speed of the auxiliary network A. And output to the auxiliary network A as a reception auxiliary signal (a801). When the main signal frame is detected, the received frame (a1301) is discarded because the received frame (a1301) is processed by the frame circuit 2 (a9). Therefore, in the wireless transmission device of the present invention, since the control frame is detected before the speed conversion reception memory 1 (a7), the control frame can be detected without being affected by the transmission delay due to the memory in the device. It is.

FIG. 8 shows a flowchart of the first operation of the transmission signal selector switch (a3).
(1) Step S201
The operation state determination unit (a3-1) inside the transmission signal changeover switch (a3) monitors the pause frame selection control signal (a601) from the control frame detection circuit (a6).
(2) Step S202
When the control frame detection circuit (a6) detects the transmission stop frame, the operation state determination unit (a3-1) receives the transmission stop frame as the pause frame selection control signal (a601) and pauses from the normal state (C1). Transition to state (C2).
(3) Step S203
When the control frame detection circuit (a6) detects the transmission resumption frame, the operation state determination unit (a3-1) receives the transmission stop frame as the pause frame selection control signal (a601) and starts normal from the pause state (C2). The state transitions to the state (C1), and the result is output to the frame selection logic unit (a3-2) as a state notification signal (a3-101).
(4) Step S204
The frame selection logic unit (a3-2) is based on the state notification signal (a3-101) from the operation state determination unit (a3-1) and the memory usage notification signal (a702) from the reception memory 1 (a7). The frame is selected according to the frame switching logic, and the result is output as a frame switching control signal (a302) to the control frame generation circuit (a5) and the frame circuit 1 (a2).
(5) Step S205
When the selector (a3-3) selects the main signal frame according to the frame switching control signal (a302) from the frame selection logic unit (a3-2), the selector (a3-3) transmits the main signal frame (from the frame circuit 1 (a2)). When selecting a201) and selecting a control frame, the transmission control signal frame (a501) from the control frame generation circuit (a5) is selected and output to the transmission circuit (a12) as a transmission frame after switching (a301). .
(6) Step S206
The transmission circuit (a12) multiplexes the post-switching transmission frame (a301) from the transmission signal changeover switch (a3) into the wireless transmission path frame, and then transmits from the physical interface in the speed conversion unit (a11) to the wireless transmission path (20). To a wireless transmission path (20) having a transmission capacity different from that of the user networks A and B as a transmission transmission signal (a1201).

FIG. 9 shows a flowchart of the second operation of the transmission signal selector switch (a3).
(1) Step S301
The receiving circuit (a13) receives the received transmission signal (a1300) received from the terminal station B (b10) of the opposite station via the wireless transmission path (20) having a transmission capacity different from that of the user network A. ) To the physical interface signal in the speed converter (a11), and then the received frame (a1301) is separated from the radio transmission path frame and output to the frame circuit 2 (a9).
(2) Step S302
When the reception frame (a1301) from the reception circuit (a13) is a control frame, the frame circuit 2 (a9) discards the reception frame (a1301) for processing by the control frame detection circuit (a6).
(3) Step S303
When the reception frame (a1301) is the main signal frame, the frame circuit 2 (a9) separates the MAC frame and writes it to the reception memory 1 (a7) at the signal speed of the wireless transmission path (20).
(4) Step S304
The reception memory 1 (a7) reads out the written MAC frame at the signal speed of the user network A, converts the signal speed between the user network A and the wireless transmission path, and then outputs it as a reception LAN signal (a701). To do.
(5) Step S305
The reception memory 1 (a7) determines whether the current memory usage is greater than or equal to a preset upper limit set value or less than the lower limit set value and uses the result as a memory usage notification signal (a702) as a transmission signal changeover switch. Output to (a3).
(6) Step S306
The control frame detection circuit (a6) determines the type when the reception frame (a1301) from the reception circuit (a13) is a control signal frame.
(7) Step S307
When detecting the transmission stop frame / transmission restart frame, the control frame detection circuit (a6) outputs the result to the transmission signal changeover switch (a3) as a pause frame selection control signal (a601).
(8) Step S308
When detecting the pause frame, the control frame detection circuit (a6) separates the auxiliary signal and writes it in the reception memory 2 (a8) at the signal speed of the wireless transmission path (20).
(9) Step S309
The reception memory 2 (a8) reads the auxiliary signal of the reception memory 2 (a8) at the signal speed of the auxiliary network A, and outputs it to the auxiliary network A as a reception auxiliary signal (a801).
(10) Step S310
When the control frame detection circuit (a6) detects the main signal frame, the control frame detection circuit (a6) discards the reception frame (a1301) in order to process the reception frame (a1301) by the frame circuit 2 (a9).

  Therefore, in the wireless transmission device of the present invention, flow control is performed by detecting the difference between the transmission capacity of the user network and the wireless transmission capacity from the usage amount of the reception memory that converts the signal speed between the user network and the wireless transmission path. . Therefore, even when the transmission capacity of the user network is small with respect to the wireless transmission path, by transmitting a transmission stop frame to the opposite station and performing flow control, the transmission of the main signal is stopped, and the reception memory overflows. Occurrence can be prevented.

  Further, when a transmission stop frame is received in the flow control, the auxiliary signal is multiplexed with the payload of the pause frame to be transmitted instead of the main signal frame, so that the signal of the auxiliary network is transmitted. It is possible to use an unused wireless transmission path band for signal transmission, and efficiently use the wireless transmission path band, which is a finite resource, by transmitting monitoring control signals etc. of the wireless transmission device via the auxiliary network It becomes possible to do.

The second embodiment of the present invention will be described below.
In the first embodiment shown in FIG. 2, the control signal frame generated by the control frame generation circuit (a5) is multiplexed and transmitted / received by the transmission circuit (a12) to the payload (F5) of the wireless transmission path frame shown in FIG. As shown in FIG. 10, by directly multiplexing only the control signal to the overhead (F4) of the wireless transmission path format in FIG. 3, control signal transmission such as transmission stop / retransmission can be performed. Is possible.

FIG. 10 is a block diagram showing a radio transmission apparatus according to the second embodiment of the present invention.
Basically, it is the same as that of the first embodiment shown in FIG. 2, but the control signal generation circuit (a14, b14) is replaced with the control frame generation circuit (a5, b5) in the speed conversion unit (a11, b11). It is provided.

Here, since the internal configurations of the terminal station A (a10) and the terminal station B (b10) in FIG. 2 are the same, the terminal station A (a10) will be described. The same applies to the terminal station B (b10).
When transmitting a pause frame, the control signal generation circuit (a14) outputs the transmission control frame signal (a501) to the transmission signal changeover switch (a3) as in FIG. 2, but in the case of a transmission stop / transmission restart frame, The transmission control signal (a1401) is output to the transmission circuit (a12), multiplexed on the overhead (F4) of the wireless transmission path frame shown in FIG. 3, and then output as the transmission transmission signal (a1201). The receiving circuit (a13) separates the transmission stop / restart control signal from the overhead (F4) of the wireless transmission path frame shown in FIG. 3 of the received transmission signal (a1300), and uses it as a pause frame selection control signal (a601). The signal is output to the transmission signal changeover switch (a3) and used for the determination of the operation state by the operation state determination unit (a3-1) in FIG. As described above, the overhead (F4) of the wireless transmission path frame shown in FIG. 3 is used for transmission of the control signal for flow control, and the payload (F5) of the wireless transmission path frame shown in FIG. 5 is used for transmission of the control signal. Therefore, it is possible to prevent a decrease in transmission efficiency due to flow control.

The third embodiment of the present invention will be described below.
As shown in FIG. 11, it is possible to employ a method in which the overhead (F1) of the frame different from the MAC frame of FIG. 3 is used instead of the overhead (F4) of the wireless transmission path frame of FIG.

FIG. 11 is a block diagram showing still another embodiment of the wireless transmission apparatus of the present invention.
The output destination of the transmission control signals (a1401, b1401) from the control signal generation circuits (a14, b14) and the output source of the pause frame selection control signals (a601, b601) are different from the embodiment of FIG.

Here, since the internal configurations of the terminal station A (a10) and the terminal station B (b10) in FIG. 2 are the same, the terminal station A (a10) will be described. The same applies to the terminal station B (b10).
The transmission control signal (a1401) from the control signal generation circuit (a14) is output to the frame circuit 1 (a2), the control signal is multiplexed on the overhead (F1) of the frame different from the MAC frame shown in FIG. 3, and In the frame circuit 2 (a9), the pause frame selection control signal (a601) is separated from the overhead of the received frame signal (a9) and output to the transmission signal selector switch (a3), which is the same as in the configuration of FIG. It is possible to obtain the effect.

Finally, the features of the present invention will be described in detail.
In the terminal station A (a10) of FIG. 2, when the memory usage of the reception memory 1 (a7) exceeds a preset upper limit, the wireless transmission capacity is larger than the transmission capacity of the user network A and the reception memory 1 (a7). ), The transmission signal changeover switch (a3) transmits the transmission stop frame from the control frame generation circuit (a5) to the terminal station B (b10) which is the opposite station. The transmission of the main signal frame from the station B (b10) is stopped. On the contrary, when the memory usage of the reception memory 1 (a7) falls below the set lower limit value, there is no possibility of overflow in the reception memory 1 (a7). ) To resume transmission of the main signal frame from the terminal station B (b10).

  When the control frame detection circuit (a6) detects a transmission stop frame from the terminal station B (b10), an overflow may occur in the reception memory 1 (b5) of the terminal station B (b10). Therefore, the transmission signal selector switch (a3) transmits the pause frame from the control frame generation circuit (a5) to the terminal station B (b10) and stops the transmission of the main signal frame. On the other hand, when a transmission resume frame is detected, there is no possibility of overflow in the reception memory 1 (b5) of the terminal station B (b10), so the main signal frame from the frame circuit 1 (a2) is used as the terminal station B. To (b10). Here, in the pause frame, the transmission auxiliary signal (a400) from the auxiliary network A is multiplexed, and when the pause frame from the terminal station B (b10) is received, the multiplexed auxiliary signal is separated. And output as a reception auxiliary signal (a801).

  As described above, in the present invention, it is possible to realize flow control by the wireless transmission device itself without using the IEEE 802.3-compliant flow control function by LAN devices such as layer 2 switch, layer 3 switch, and MAC provided inside and outside the device. Thus, even when the transmission capacities of the user network A, the wireless transmission path, and the user network B in FIG. 2 are different, it is possible to transmit a signal without causing an overflow in the reception memory 1 (a5, b5). Become. Also, a wireless transmission device that can use a finite wireless band more efficiently by using a wireless transmission path band that has not been used due to flow control by multiplexing / separating auxiliary signals in pause frames. I will provide a.

  Further, in a wireless transmission device that multiplexes and transmits a LAN signal in a frame different from a MAC frame, the flow control signal is transmitted in a frame different from the MAC frame, thereby realizing flow control between the wireless transmission devices, Absorb the difference between user network transmission capacity and wireless transmission capacity. As a result, it is possible to suppress the overflow in the main signal reception memory that is caused by the difference between the transmission capacity of the user network and the wireless transmission capacity. Similarly, it is possible to suppress the overflow of the transmission capacity difference between the user networks facing each other via the wireless transmission device.

  Further, in the wireless transmission device of the present invention, when transmission is stopped by unique flow control, the auxiliary network signal is transmitted using a pause frame that is transmitted instead of the main signal, thereby increasing the efficiency of use of the wireless transmission path band. Is possible.

FIG. 1 is a block diagram showing a conventional wireless transmission apparatus. FIG. 2 is a block diagram illustrating the wireless transmission device according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration example of each frame. FIG. 4 is a flowchart of the operation of the wireless transmission device. FIG. 5 is a block diagram showing a transmission signal selector switch. FIG. 6 is a schematic diagram showing state transition. FIG. 7 is a flowchart showing the operation in the frame switching logic. FIG. 8 is a flowchart of the first operation of the transmission signal selector switch. FIG. 9 is a flowchart of the second operation of the transmission signal selector switch. FIG. 10 is a block diagram showing a radio transmission apparatus according to the second embodiment of the present invention. FIG. 11 is a block diagram illustrating a wireless transmission device according to the third embodiment of the present invention.

Explanation of symbols

x10 Terminal X
y10 ... Terminal Y
x1 to x4, y1 to y4, a plurality of call terminals 1 to 4
x5, y5 ... Terminal station device x6, y6 ... Layer 3 switch x7, y7 ... Automatic bandwidth switching control device x8, y8 ... Transmission / reception device a10 ... Terminal station A
b10 ... Terminal B
a11, b11 ... speed converter a12, b12 ... transmission circuit a13, b13 ... reception circuit a1, b1 ... transmission memory 1
a2, b2 ... Frame circuit 1
a3, b3 ... transmission signal selector switch a4, b4 ... transmission memory 2
a5, b5 ... control frame generation circuit a6, b6 ... control frame detection circuit a7, b7 ... reception memory 1
a8, b8 ... Reception memory 2
a9, b9... Frame circuit 2
a14, b14 ... control signal generation circuit 20 ... wireless transmission line

Claims (10)

A wireless transmission device connected to each of a wireless transmission path, a user network, and an auxiliary network ,
A transmission circuit for transmitting a control signal using a frame different from a MAC frame to the wireless transmission path;
A receiving circuit for receiving another control signal using a frame different from the MAC frame from the wireless transmission path;
Connected to said transmitting circuit and said receiving circuit transmits and receives and detects a control frame including a control signal in the preceding stage without passing through the signal rate conversion memory in the device, during transmission stop by flow control, the main signal A rate converter that multiplexes and transmits an auxiliary network signal on a payload of a pause frame transmitted instead of a frame ,
The speed converter is
A first transmission memory for storing a transmission LAN signal from the user network at a signal speed of the user network;
A transmission signal switching switch for generating a frame switching control signal;
When the main signal frame is selected according to the frame switching control signal from the transmission signal switch, the transmission LAN signal is read from the first transmission memory at the signal speed on the wireless transmission path side, the speed conversion is performed, and the MAC frame and Is a first frame circuit that multiplexes into different frame formats and outputs to the transmission signal changeover switch as a transmission main signal frame;
A second transmission memory for receiving a transmission auxiliary signal from the auxiliary network and storing it at a signal speed of the auxiliary network;
A control frame generation circuit that reads out a transmission auxiliary signal from the second transmission memory at a signal speed on the wireless transmission path side, multiplexes the pause signal into a pause frame, and outputs the pause frame to the transmission signal switch;
When the received frame from the receiving circuit is a control frame, it is determined whether it is a transmission stop frame or a transmission restart frame, and the result is output to the transmission signal changeover switch as a pause frame selection control signal A wireless transmission device comprising: A radio transmission apparatus according to claim 1,
When the control frame is selected according to the frame switching control signal from the transmission signal switching switch, the control frame generation circuit selects one of the pause frame / transmission stop frame / transmission resume frame as the transmission control signal frame. A wireless transmission device that outputs to a transmission signal selector switch. A radio transmission apparatus according to claim 2,
The transmission signal selector switch selects one of a transmission control signal frame from the control frame generation circuit and a transmission main signal frame from the first frame circuit, and outputs it to the transmission circuit as a transmission frame after switching. Wireless transmission device. A wireless transmission device according to any one of claims 1 to 3,
The speed converter is
A first reception memory that reads out the written MAC frame at a signal speed on the user network side and outputs it to the user network as a reception LAN signal;
A second reception memory that reads out the written transmission auxiliary signal at the signal speed of the auxiliary network and outputs the signal as a reception auxiliary signal;
And a second frame circuit that separates a MAC frame and writes the MAC frame to the first reception memory at a signal speed of the wireless transmission path when the reception frame from the reception circuit is a main signal frame. A radio transmission apparatus according to claim 4,
When the received frame from the receiving circuit is a pause frame, the control frame detecting circuit separates a transmission auxiliary signal from the received frame from the receiving circuit and transfers it to the second receiving memory at the signal speed of the wireless transmission path. Write Wireless transmission device. A wireless transmission device according to claim 4 or 5,
The first reception memory monitors its own memory usage, determines whether the current memory usage is greater than or equal to a preset upper limit set value or less than a lower limit set value, and uses the result as a memory usage notification signal. A wireless transmission device that outputs to a transmission signal selector switch. A radio transmission apparatus according to claim 6,
The transmission signal selector switch selects either the main signal frame or the control frame based on the pause frame selection control signal from the control frame detection circuit and the memory usage notification signal from the first reception memory. and, control and selects the type of control frame, the result as a frame switching control signal, a radio transmission device that outputs said control frame generation circuit to said first frame circuit. A wireless transmission device according to claim 6 or 7,
The transmission signal selector switch is
An operation state determination unit that performs state transition using a pause frame selection control signal from the control frame detection circuit;
Based on a state notification signal from the operation state determination unit and a memory usage notification signal from the first reception memory, a frame is selected according to a frame switching logic, and the result is used as a frame switching control signal. A frame selection logic unit for outputting to one frame circuit;
According to the frame switching control signal from the frame selection logic unit, when the main signal frame is selected, the transmission main signal frame from the first frame circuit is selected, and when the control frame is selected, the control frame generation circuit A radio transmission apparatus comprising: a selector that selects a transmission control signal frame and outputs the transmission control signal frame to the transmission circuit as a transmission frame after switching. A radio transmission apparatus according to claim 8,
The operation state determination unit is a wireless transmission device that transitions from a normal state to a dormant state when the control frame detection circuit detects a transmission stop frame. A wireless transmission device according to claim 8 or 9,
The operation state determination unit, when the control frame detection circuit detects a transmission resume frame, makes a transition from a dormant state to a normal state and outputs the result as a state notification signal to the frame selection logic unit.

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