JP2005318395A - Radio network system, packet loss reducing method for radio network system and radio communications apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to suppress a quality decrease due to a packet loss even in a communication via a radio network which does not have retransmission function. <P>SOLUTION: A radio network system performs a packet communication via a radio network by first and second radio communications apparatuses. The first radio communications apparatus generates processings to copy the packet to be transmitted to generate a plurality of the same packets, and sends the plurality of the same packets to a plurality of different network routes. The second radio communications apparatus receives the packet from one or a plurality of the network routes, supervises the received packages, and discards the same received packet as the packet received in the past. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless network system, a packet loss reduction method for a wireless network system, and a wireless communication apparatus, and can be applied to, for example, voice communication using a wireless IP (internet protocol) network.

Voice communication using an IP network such as the Internet has become popular. In voice communication in an IP network, UDP (user datagram protocol), which is a connectionless protocol, is generally used as a protocol. Since UDP does not have a retransmission function, playback is performed when packet loss occurs. This leads to lack of sound on the side. In order to alleviate such sound loss, a voice interpolation method defined in Non-Patent Document 1 or the like has been used.
ITU-T G. 711 Appendix I

  In recent years, voice communication using a wireless IP network has begun to attract attention. In the case of a wireless IP network, the rate of occurrence of packet loss is higher than that of a wired network, and there is a possibility that sound deficiency cannot be sufficiently compensated only by voice interpolation on the playback side. The problem of quality deterioration due to packet loss similarly occurs not only for voice packets but also for image packets.

  Therefore, there is a demand for a wireless network system, a packet loss mitigation method for a wireless network system, and a wireless communication apparatus that can suppress quality degradation due to packet loss even in communication via a wireless network without a retransmission function.

  According to a first aspect of the present invention, in the wireless network system in which the first and second wireless communication devices perform packet communication via a wireless network, (1) the first wireless communication device tries to (1-1) transmit A packet copy unit that generates a plurality of identical packets by copying the packet to be (1) and (1-2) a wireless transmission unit that transmits the plurality of identical packets to one or a plurality of network paths of the wireless network. (2) the second wireless communication apparatus (2-1) wireless receiving means for receiving packets from one or a plurality of network paths; (2-2) monitoring received packets and receiving them in the past And packet duplication avoiding means for discarding the same received packet as the received packet.

  According to a second aspect of the present invention, there is provided a wireless communication apparatus to which the first wireless transmission apparatus corresponds in the wireless network system that performs packet communication via the wireless network from the first wireless communication apparatus to the second wireless communication apparatus. A packet copy means for copying a packet to be generated to generate a plurality of identical packets; and a wireless transmission means for sending the plurality of identical packets to one or a plurality of network paths of the wireless network. To do.

  According to a third aspect of the present invention, there is provided a wireless communication apparatus to which the second wireless transmission apparatus corresponds in the wireless network system that performs packet communication via a wireless network from the first wireless communication apparatus to the second wireless communication apparatus. Alternatively, it comprises radio receiving means for receiving packets from a plurality of network paths, and packet duplication avoiding means for monitoring received packets and discarding received packets that are identical to previously received packets.

  A fourth aspect of the present invention is a packet loss reduction method for a wireless network system that performs packet communication from a first wireless communication apparatus to a second wireless communication apparatus via a wireless network, wherein the first wireless communication apparatus The packet to be transmitted is copied to generate a plurality of identical packets, which are sent out to one or more network paths of the wireless network, and the second wireless communication device is sent from one or more network paths. It is characterized by receiving a packet, monitoring the received packet, and discarding a received packet identical to a packet received in the past.

  According to the present invention, since redundant communication using a plurality of network paths is performed in packet communication via a wireless network, even if the wireless network does not have a retransmission function, quality degradation due to packet loss is reduced. Can be suppressed.

(A) First Embodiment Hereinafter, referring to the drawings, a first embodiment in which a wireless network system, a packet loss reduction method of a wireless network system, and a wireless communication apparatus according to the present invention are applied to voice communication using a wireless IP network will be described. Details will be described.

  In the first embodiment, as in other embodiments described later, an attempt is made to reduce the influence of packet loss by providing redundancy to voice packets transmitted and received in a wireless IP network.

  FIG. 1 is an explanatory diagram of the concept of a method for reducing voice packet loss in the first embodiment. The example shown in FIG. 1 is an example in which voice packets are exchanged between a wired LAN 1 and a wired LAN 2 through a wireless IP network (for example, a wireless LAN network) 3 according to IP.

  The wireless LAN access point device (wireless communication device) 4 connected to the wired LAN 1 on the transmission side determines whether or not the packet from the wired LAN 1 is a voice packet. A voice packet is copied to a plurality of wireless LAN access point apparatuses 5-1 to 5-M (one of which may be the wireless LAN access point apparatus 6 on the receiving side) as connection partners. Send the same thing. On the other hand, in the wireless LAN access point device 6 connected to the wired LAN 2 on the reception side, a plurality of wireless LAN access point devices 7-1 to 7-N (one of which is a wireless on the transmission side) The sequence number of the voice packet sent from the LAN access point device 4 may be monitored, the first voice packet is received, and the voice packet having the same sequence number as the voice packet received in the past is received. If it arrives, discard it. Copy transmission from the wireless LAN access point device (wireless communication device) 4 on the transmission side may be for the same network path.

  Note that each wireless LAN access point device has both a transmission configuration and a reception configuration, but in FIG. 1, it is shown as a one-way flow of voice packets.

  FIG. 2 shows a main part of the packet transmission unit configuration of each wireless LAN access point device (here, device 4). 2, the packet transmission unit 10 includes a buffer memory 11, a copy control unit 12, a packet distribution unit 13, and a plurality (M) of wireless transmission units 14-1 to 14-M.

  The buffer memory 11 is made of, for example, a FIFO memory, and buffers packets arriving from the wired LAN 1, and the notation shown in FIG. The buffer memory 11 copies and outputs a predetermined number of corresponding packets (voice packets) when a later-described copy output instruction is given. Note that at the time of copy output, high-speed reading may be performed so that the wireless transmission units 14-1 to 14-M, which will be described later, return to the normal packet speed.

  The copy control unit 12 determines whether or not the packet arriving from the wired LAN 1 is a voice packet (for example, by checking the payload type). In the case of a voice packet, the copy control unit 12 transmits the voice packet to the buffer memory 11. Instructs copy output. In other words, in the case of an image packet, a data packet, or a control packet, the buffer memory 11 is simply instructed to output. Here, the copy control unit 12 may store information such as the number of copies and the relay node associated with the destination or the group to which the destination belongs, and this information may be included in the copy output instruction. Note that the number of copies may be constant regardless of the destination.

  The packet distribution unit 13 gives a packet (image packet, data packet, or control packet) simply read from the buffer memory 11 to a predetermined (or all) wireless transmission unit 14-m, and is copied from the buffer memory 11 The voice packet is distributed to a plurality (M) of wireless transmission units 14-1 to 14-M. When the copy output instruction includes information such as the number of copies and relay nodes, and the number of copies is smaller than the number of wireless transmission units (M), the copy is output to some wireless transmission units determined by the relay node information. Distribute voice packets. The packet distribution unit 13 may store correspondence information between the relay node and the wireless transmission unit, and the copy control unit 12 may store correspondence information. .

  Each of the wireless transmission units 14-1,..., 14-M converts the input packet into a wireless signal and radiates it to the wireless space. Here, each of the wireless transmission units 14-1,..., 14-M performs different wireless channel processing, for example. For example, different radio frequencies may be assigned, or different spreading codes may be assigned with the same frequency or different spreading codes. Note that only one wireless transmission unit may be provided, and the wireless transmission unit may be used in a time-sharing manner to perform wireless transmission of copy voice packets to a plurality of nodes (relay nodes or destination nodes). In this case, information specifying a relay node (wireless LAN access point device) or information specifying a route may be added to each voice packet for wireless transmission.

  FIG. 3 shows a main part of the packet reception unit configuration of each wireless LAN access point device (here, device 6). In FIG. 3, the packet receiver 20 includes a plurality (N) of radio receivers 21-1 to 21-N, a plurality (N) of latches 22-1 to 22-N, a duplicate reception controller 23, and a buffer. A memory 24 is included.

  Each of the wireless reception units 21-1,..., 21-N returns a wireless signal from a node (relay node or transmission source node) corresponding to itself to a baseband signal packet.

  Each of the latch units 22-1 to 22-N latches a packet obtained by the corresponding radio reception unit 21-1, to 21-N.

  The duplicate reception control unit 23 takes out the packets latched from the latch units 22-1,..., 22-N and stores them in the buffer memory 24 according to, for example, a polling method. Further, the duplicate reception control unit 23 checks whether or not the latched packet is destined for itself (or relay node), and if it is not intended for the destination (or relay node), the buffer memory 24 Disappear from. If it is a packet destined for itself (or a relay node), it is checked whether it is a voice packet. If it is a voice packet, its sequence number matches the sequence number stored internally. It is further determined whether or not there is. When the sequence number of the voice packet immediately after being added to the buffer memory 24 matches the sequence number stored in the buffer memory 24, the duplicate reception control unit 23 deletes the packet from the buffer memory 24. If the sequence number of the voice packet does not match the sequence number stored internally, the sequence number stored internally is not added to the buffer memory 24 without operating the buffer memory 24. Update to the sequence number of the voice packet.

  The buffer memory 24 is, for example, a FIFO memory, and stores received packets without duplicating the same packets, as is apparent from the above.

  Although not shown, the relay node has a configuration of a packet receiving unit as shown in FIG. 3 and a configuration of a packet transmitting unit as shown in FIG. The relay node takes in the received packet when it is destined for itself, and relays it when it is destined for another node. Note that, at the time of relay transmission, a packet may be copied and transmitted to a plurality.

  According to the first embodiment, it is possible to reduce the influence of packet loss on the wireless IP network 3 by transmitting a plurality of the same voice packets on the wireless IP network 3. That is, if even one of a plurality of the same packets can pass, the influence of the packet loss can be eliminated, and the quality deterioration due to the packet loss can be suppressed. Since only voice packets are copied, the traffic increase of the wireless IP network 3 is suppressed as much as possible.

(B) Second Embodiment Next, a second embodiment of the present invention will be described focusing on differences from the first embodiment with reference to the drawings.

  In the case of the first embodiment, the wireless LAN access point device that is the transmission source of the voice packet copies the packet by a predetermined number of copies for each destination (or destination group) and performs redundant transmission. In the second embodiment, the number of voice packet copies is dynamically changed for each destination and according to the communication status with the destination.

  In FIG. 4, for example, a transmitting-side wireless LAN access point device (wireless communication device) 4 connected to the wired LAN 1 performs wireless transmission using the wireless LAN access point device 6-1 connected to the wired LAN 2-1 as a receiving side. When the number of copies is selected according to the status of the wireless line with the device 6-1, and the wireless LAN access point device 6-2 connected to the wired LAN 2-2 is wirelessly transmitted as a receiving side. For this, the number of copies corresponding to the status of the wireless line with the device 6-2 is selected. For example, a different copy number may be applied such that the number of copies is 3 in wireless communication with the device 6-1 and the number of copies is 2 in wireless communication with the device 6-2.

  FIG. 5 is a block diagram showing the main configuration of the packet transmission unit of the wireless LAN access point device of the second embodiment. The same reference numerals are given to the same and corresponding parts as in FIG. 2 according to the first embodiment. It is attached.

  The packet transmission unit 10A according to the second embodiment includes a communication state determination unit 15 in addition to the buffer memory 11, the copy control unit 12, the packet distribution unit 13, and a plurality (M) of wireless transmission units 14-1 to 14-M. Have

  The newly provided communication state determination unit 15 determines the state of a wireless line with another wireless LAN access point device and determines the number of voice packet copies. For example, the communication state determination unit 15 is provided with reception information of a TCP (transmission control protocol) packet, determines whether or not it is an instruction for retransmission, and if the retransmission is an instruction, The stored quality information of the transmission source (voice packet destination) is updated, and the copy number information is updated as appropriate. For example, the quality information stage is divided into a plurality of stages, and the number of copies is associated with each stage in advance. Then, the number of retransmissions for each predetermined communication time is obtained as quality information, and the number of copies corresponding to the stage to which the quality information belongs is determined as the number of copies related to the destination.

  When voice packet communication becomes necessary, the copy number determined at this time is applied.

  Note that packet communication according to TCP is not limited to control packet communication, and may be image packet or data packet communication. In addition, the configuration of the voice packet receiver in the wireless LAN access point device on the receiving side is the same as that in the first embodiment. Although not mentioned in the first embodiment, general transmission / reception of control packets and the like is performed. Since it has a configuration, it has a TCP packet transmission configuration.

  Also according to the second embodiment, the effect that the packet loss can be suppressed can be achieved as in the first embodiment. According to the second embodiment, it is possible to further suppress an increase in traffic of the wireless IP network by changing the number of voice packet copies according to the wireless state to the destination.

(C) Third Embodiment Next, a third embodiment of the present invention will be described with a focus on differences from the first and second embodiments with reference to the drawings.

  In the second embodiment described above, the wireless LAN access point device on the voice packet transmission side determines the number of copies according to the communication state. In the third embodiment, as shown in FIG. The wireless LAN access point device 6 on the voice packet receiving side determines the number of copies according to the communication state and notifies the wireless LAN access point device 4 on the voice packet transmitting side.

  FIG. 7 is a block diagram showing the main configuration of the packet transmission unit of the wireless LAN access point device of the third embodiment. The same reference numerals are given to the same and corresponding parts as in FIG. 2 according to the first embodiment. It is attached. FIG. 8 is a block diagram showing the main configuration of the packet receiving unit of the wireless LAN access point device of the third embodiment, which is the same as and corresponding to FIG. 3 according to the first embodiment. A reference numeral is attached.

  The packet transmission unit 10B according to the third embodiment includes a negotiation detection unit 16 in addition to the buffer memory 11, the copy control unit 12, the packet distribution unit 13, and a plurality (M) of wireless transmission units 14-1 to 14-M. Have. The packet receiver 20B of the third embodiment includes a plurality (N) of radio receivers 21-1 to 21-N, a plurality (N) of latch units 22-1 to 22-N, and a duplicate reception controller 23. In addition to the buffer memory 24, a copy number determination unit 25 is provided.

  When the negotiation detection unit 16 detects a negotiation (call establishment) packet, the negotiation detection unit 16 clears the number of copies (information) provided for the current voice communication stored in the copy control unit 12 to zero. In other words, at the initial stage of communication, voice packets are not copied and are sent and received through one route.

  Note that the copy control unit 12 of the third embodiment clears the corresponding copy number to zero in response to the zero clear command from the negotiation detection unit 16, and when the copy number change command from the packet reception unit 20B is given. The number of copies stored in the number of copies of the command is changed. Here, the copy number change command may be information on the copy number itself after the change, or information instructing to increase or decrease the copy number.

  The copy number determination unit 25 of the packet reception unit 20B detects a communication state, appropriately forms a copy number change command, and notifies the transmission side using means having retransmission control such as TCP. For example, the copy number determination unit 25 calculates a packet loss rate as a communication state from the copy number and sequence number at that time. Then, the wireless LAN access point apparatus 4 is instructed for the number of copies so that the packet loss rate is equal to or less than α% (a predetermined value) at regular intervals.

  When the packet loss rate at the time of monitoring is β% and the copy number is Cp, the copy number Cn at which the packet loss rate is α% or less is obtained as follows.

(I) In the case of β> 0 Cn = (the smallest integer not less than (((Cp + 1) × (β / α))) − 1 (1)
However, when Cn <0, Cn = 0 is set. (II) When β = 0, Cn = Cp−1 (2)
However, when Cn <0, the method of determining the copy number Cn with Cn = 0 is not limited to the method according to the equations (1) and (2). When the packet loss rate being monitored is large Any method can be used as long as Cn is increased and Cn is decreased when the packet loss rate is small.

  According to the third embodiment, in addition to the effects of the first and second embodiments, the following effects can be expected. That is, since the number of voice packet copies is dynamically controlled by setting 0 as an initial value in accordance with the state of the wireless IP network 3, the increase in traffic on the wireless IP network 3 is minimized and packet loss is reduced. The impact can be reduced.

  In the second embodiment, the number of copies is dynamically controlled. However, in the case of the third embodiment, dynamic control can be executed for each communication.

  As a modified embodiment of the third embodiment, an upper limit of the copy number Cn may be set. Such upper limit information of the copy number Cn may be held by the copy control unit 12, or may be held by the copy number determination unit 25. Further, the upper limit of the copy number Cn may be changed depending on the destination.

  When an upper limit is set for the number of voice packet copies, an excessive increase in traffic in the wireless IP network 3 can be suppressed, and finer network traffic control is possible compared to the third embodiment.

(D) Fourth Embodiment Next, a fourth embodiment of the present invention will be described focusing on differences from the third embodiment with reference to the drawings.

  FIG. 9 is a block diagram showing the main configuration of the packet receiving unit and the packet transmitting unit of one wireless LAN access point apparatus according to the fourth embodiment, and the same and corresponding parts as those in FIGS. 7 and 8 described above. Are indicated by corresponding reference numerals. Note that an element whose code end is “−S” represents a component of the packet transmission unit, and an element whose code end is “−R” represents a component of the packet receiving unit.

  In general, in communication between two wireless LAN access point apparatuses, the communication status is often the same in both directions. In the fourth embodiment, based on this property, instead of notifying the opposing wireless LAN access point device of the copy number determined by the copy number determination unit 25-R, the voice packet from its own packet transmission unit is transmitted. The number of copies is set in the copy control unit 12-S. Note that the copy number determination unit 25-R may divert the copy number from itself as the copy number Cp at that time, and the average value of a predetermined number of received packets of the same sequence number received recently ( Alternatively, the maximum value may be applied.

  Here, the fourth embodiment is based on the premise that the two opposing wireless LAN access point apparatuses have the configuration shown in FIG.

  According to the fourth embodiment, substantially the same effect as in the third embodiment can be obtained, and it is also possible to eliminate the need to send and receive a copy number change command between two wireless LAN access point devices. There is also an effect of being able to.

  As a modified embodiment of the fourth embodiment, an example in which an upper limit of the copy number Cn is defined can be mentioned.

(E) Other Embodiments In each of the above embodiments, the case where a packet to be copied is a voice packet has been described. However, the packet is not limited to a voice packet as long as quality degradation due to packet loss is a problem. For example, even for an image packet, the present invention can be applied to any system as long as quality degradation due to packet loss is a serious problem.

  In addition, each of the above embodiments is a method of reducing the packet loss seen from the receiving side (the loss is not lost when even one identical packet is received). However, as many as one packet with a certain sequence number is used. Of course, the interpolation process may be executed when reception is not possible.

  Further, in each of the above embodiments, the wireless network is a wireless IP network, but the present invention may be applied to a wireless network that complies with a protocol other than IP. The present invention is particularly effective for a wireless network system without a retransmission function, but can also be applied to a wireless network system with a retransmission function.

  Furthermore, in each of the above embodiments, the device that transmits and receives to the wireless network is a wireless LAN access point device, but the wireless communication device is not limited to this. For example, a single wireless communication device may be used.

It is a conceptual explanatory view of the packet loss mitigation method in the first embodiment. It is a block diagram which shows the principal part structure of the packet transmission part of the wireless LAN access point apparatus of 1st Embodiment. It is a block diagram which shows the principal part structure of the packet receiver of the wireless LAN access point apparatus of 1st Embodiment. It is a conceptual explanatory drawing of the packet loss reduction method in 2nd Embodiment. It is a block diagram which shows the principal part structure of the packet transmission part of the wireless LAN access point apparatus of 2nd Embodiment. It is a conceptual explanatory drawing of the packet loss reduction method in 3rd Embodiment. It is a block diagram which shows the principal part structure of the packet transmission part of the wireless LAN access point apparatus of 3rd Embodiment. It is a block diagram which shows the principal part structure of the packet receiver of the wireless LAN access point apparatus of 3rd Embodiment. It is a block diagram which shows the principal part structure of the wireless LAN access point apparatus of 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 ... Wired LAN, 3 ... Wireless IP network (wireless LAN network) 4, 5-1 to 5-M, 6, 7-1 to 7-N ... Wireless LAN access point apparatus (wireless communication apparatus), 10 ... Packet transmission unit, 11 ... Buffer memory, 12 ... Copy control unit, 13 ... Packet distribution unit, 14-1 to 14-M ... Wireless transmission unit, 15 ... Communication state determination unit, 16 ... Negotiation detection unit, 20 ... Packet Receiving unit, 21-1 to 21-N ... wireless receiving unit, 22-1 to 22-N ... latching unit, 23 ... duplicate reception control unit, 24 ... buffer memory, 25 ... copy number determining unit.

Claims (15)

In a wireless network system in which the first and second wireless communication devices perform packet communication via a wireless network,
The first wireless communication device is
A packet copy means for copying a packet to be transmitted to generate a plurality of identical packets;
Wireless transmission means for transmitting a plurality of identical packets to one or a plurality of network paths of the wireless network;
The second wireless communication device is
Wireless receiving means for receiving packets from one or more network paths;
A wireless network system comprising: a packet duplication avoiding unit that monitors a received packet and discards the same received packet as a packet received in the past.   The first wireless communication apparatus includes a packet type determining unit that determines whether or not a packet to be transmitted is a voice packet, and that effectively operates the packet copy unit only when the packet is a voice packet. The wireless network system according to claim 1.   The wireless network system according to claim 1 or 2, wherein the packet copy means changes the number of packet copies depending on which device the second wireless communication device is.   The first wireless communication apparatus includes communication state detection means for detecting a communication state with the second wireless communication apparatus based on call control information received from the second wireless communication apparatus, and the packet copy The wireless network system according to claim 1 or 2, wherein the means changes the number of packet copies in accordance with the detected communication state. The second wireless communication device calculates a change value of the packet copy number based on the reception status of the same packet as the packet copy number at that time in the opposing first wireless communication device, and obtains copy number information. A copy number calculation means for notifying the opposing first wireless communication apparatus side;
The wireless network system according to claim 1 or 2, wherein the packet copy means of the first wireless communication device performs packet copy processing based on the notified copy number information.   The second wireless communication apparatus calculates a change value of the packet copy number based on the reception status of the same packet as the packet copy number at that time in the opposing first wireless communication apparatus and obtains copy number information. 3. The wireless network system according to claim 1, further comprising: a self-copy number calculating unit that supplies a packet copy unit that copies a packet from the second wireless communication device to the first wireless communication device. 4. . In the wireless communication device to which the first wireless transmission device in the wireless network system performing packet communication from the first wireless communication device to the second wireless communication device via the wireless network,
A packet copy means for copying a packet to be transmitted to generate a plurality of identical packets;
A wireless communication apparatus comprising: a wireless transmission unit that transmits a plurality of identical packets to one or a plurality of network paths of the wireless network.   8. The wireless communication according to claim 7, further comprising: a packet type determining unit that determines whether or not a packet to be transmitted is a voice packet, and that effectively operates the packet copy unit only when the packet is a voice packet. apparatus.   9. The wireless communication apparatus according to claim 7, wherein the packet copy unit changes the number of packet copies depending on which apparatus the second wireless communication apparatus is.   Communication state detecting means for detecting a communication state with the second wireless communication apparatus based on call control information arriving from the second wireless communication apparatus is provided, and the packet copy means is connected to the detected communication state. 9. The wireless communication apparatus according to claim 7, wherein the number of packet copies is changed accordingly.   9. The wireless communication apparatus according to claim 7, wherein the packet copy means performs packet copy processing based on the copy number information notified by the second wireless communication apparatus. In the wireless communication device to which the second wireless transmission device in the wireless network system that performs packet communication via the wireless network from the first wireless communication device to the second wireless communication device corresponds,
Wireless receiving means for receiving packets from one or more network paths;
A wireless communication apparatus comprising: a packet duplication avoiding unit that monitors a received packet and discards the same received packet as a packet received in the past.   The second wireless communication apparatus calculates a change value of the packet copy number based on the reception status of the same packet as the packet copy number at that time in the opposing first wireless communication apparatus and obtains copy number information. 13. The wireless communication apparatus according to claim 12, further comprising copy number calculation means for notifying the opposing first wireless communication apparatus side.   Based on the reception status of the same packet as the packet copy number at that time in the opposing first wireless communication device, a change value of the packet copy number is calculated and the copy number information is obtained from the second wireless communication device. 13. The wireless communication apparatus according to claim 12, further comprising a self-copy number calculating means for giving to a packet copy means for copying a packet to the first wireless communication apparatus. A packet loss reduction method for a wireless network system that performs packet communication from a first wireless communication device to a second wireless communication device via a wireless network,
The first wireless communication device generates a plurality of identical packets by copying a packet to be transmitted, and sends the same packet to one or a plurality of network paths of the wireless network,
The second wireless communication apparatus receives a packet from one or a plurality of network paths, monitors a received packet, and discards a received packet that is the same as a packet received in the past. Packet loss mitigation method.

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