JP2007221527A - Repeater, wireless network system using same, and program for allowing computer to execute processing in repeater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a repeater capable of suppressing an increase in delay time and that in packet error rate. <P>SOLUTION: When wireless devices 101-10p respectively execute two-way wireless communication in between wireless devices 111-11p via access points 120, 130, and 140; the access point 120 generates one relay packet by bundling a plurality of packets received from the wireless devices 101-10p, so as to transmit the generated relay packet to the access point 140 via the access point 130, and the access point 140 generates one relay packet by bundling a plurality of packets received from the wireless devices 111-11p so as to transmit the generated relay packet to the access point 120 via the access point 130. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a repeater, a wireless network system using the repeater, and a program for causing a computer to execute processing in the repeater, and in particular, a repeater configuring a mesh-type wireless network, a wireless network system using the repeater, and The present invention relates to a program for causing a computer to execute processing in a repeater.

  An ad hoc network is a network that is autonomously and instantaneously constructed by a plurality of wireless devices communicating with each other. In an ad hoc network, when two wireless devices that communicate with each other do not exist in the communication area, a wireless device located between the two wireless devices functions as a router and relays a data packet. Can be formed.

  Dynamic routing protocols that support multi-hop communication include table-driven protocols and on-demand protocols. The table-driven protocol periodically exchanges control information related to a route and constructs a route table in advance, and includes FSR (Fish-eye State Routing), OLSR (Optimized Link State Routing), and TBRPF (Topology). (Dissociation Based on Reverse-Path Forwarding) and the like are known.

  In addition, the on-demand protocol is a method for constructing a route to a destination for the first time when a data transmission request occurs, and includes DSR (Dynamic Source Routing) and AODV (Ad Hoc On-Demand Distance Vector Routing). Are known.

  In a conventional ad hoc network, when performing data communication from a transmission source to a transmission destination, a communication path is determined so that the number of hops from the transmission source to the transmission destination is as small as possible (Non-Patent Document 1).

  Further, a mesh network in which the backbone network is configured by wireless ad hoc is known (Non-Patent Document 2). This mesh network includes a plurality of access points and a plurality of slave units provided corresponding to each of the plurality of access points.

The plurality of slave units perform wireless communication with the corresponding access point in the infrastructure mode. The plurality of access points perform wireless communication with each other in the ad hoc mode. Each of the plurality of access points transmits a packet received from a plurality of slaves under its control to another access point by wireless communication, and receives a packet received from another access point under its control. Transmit to the slave unit by wireless communication.
Guangyu Pei, at al, “Fisheye state routing: a routing scheme for ad hoc wireless networks”, ICC2000. Commun., Volume 1, pp70-74, LA, June 2000. OLSR (Host and Network Association with HNA function turned on) http: // ietf. org / rfc / rfc3626. txt.

  However, in a conventional mesh type network, a plurality of slave units that exist under one access point may be connected to a plurality of slave units that exist under another access point with a VoIP (Voice over Internet Protocol) or network game. When performing communication requiring such real-time properties, when the amount of packets sent from the access point to the backbone network reaches a limit, packet loss and delay increase, and the communication state deteriorates.

  Therefore, consider the limit of the amount of packets sent from the access point to the backbone network. FIG. 17 is a schematic diagram of a mesh network for estimating the limit of the amount of packets sent from the access point to the backbone network.

  The mesh network 300 includes wireless devices 311 to 31p (p is a positive integer) and access points (APs) 320, 330, and 340.

  Access points 320, 330, and 340 constitute a backbone network. The wireless devices 311 to 31p existing under the access point 320 perform bidirectional wireless communication with the wireless devices 311 to 31p having the same number under the access point 340 via the access points 320, 330, and 340. In this case, the wireless devices 311 to 31p perform wireless communication in the infrastructure mode using the access point 320 or 340 and the frequency f1. Further, the access points 320, 330, and 340 perform wireless communication in the ad hoc mode using the frequency f2 (≠ f1).

  If a typical transmission time required to transmit one packet is T, the maximum waiting time that the access point 330 must wait before transmitting a packet is 2T regardless of the number of sessions. Furthermore, since the access point 330 needs 2T to transfer the packets sent from the access point 320 and the access point 340, the access point 330 takes the maximum amount of time until all packets are processed. Time is 4T.

  On the other hand, since the number of packets transmitted from each of the access points 320 and 340 to the backbone network is p, the number of packets that the access point 330 must relay per unit time is 2p. When the packet generation interval in each of the wireless devices 311 to 31p is G seconds, the access point 330 receives 2p / G packets per second. As a result, the transfer time interval at which the access point 330 must transfer packets per second is G / 2p.

  FIG. 18 is a diagram illustrating the relationship between the maximum waiting time and transfer time interval and the number of sessions. In FIG. 18, the vertical axis represents the maximum waiting time and the transfer time interval, and the horizontal axis represents the number of sessions. The dotted line indicates the maximum waiting time, and the solid line indicates the transfer time interval.

  The results shown in FIG. 18 are the results when the G711 uncompressed codec in the VoIP application is used, the voice data size is 160 bytes, and the packet generation time interval is 20 msec.

  From the result shown in FIG. 18, the dotted line and the solid line intersect when the number of sessions is “4”. Therefore, when the number of sessions exceeds “4”, the access point 330 may start buffering packets. That is, the limit value of the amount of packets transmitted from the access points 320 and 340 to the backbone network is 8 / G [number / second]. The packet generation interval G is set to 0.02 seconds, for example.

  FIG. 19 is a diagram illustrating the relationship between the delay and packet error rate and the number of sessions. In FIG. 19, the vertical axis represents the delay and the packet error rate, and the horizontal axis represents the number of sessions. A broken line indicates a delay, and a bar graph indicates a packet error rate.

  The results shown in FIG. 19 are based on an experiment assuming VoIP in the same topology (that is, the topology shown in FIG. 17) used for estimating the limit value of the amount of packets transmitted from the access points 320 and 340 to the backbone network. It is a result. More specifically, the result shown in FIG. 19 is a result when 15,000 160-byte packets are transmitted at 20 msec intervals assuming VoIP.

  The wireless devices 311 to 31p existing under the access point 320 perform two-way wireless communication with the wireless devices 311 to 31p having the same number under the access point 340 via the access points 320, 330, and 340, At the same time, the number of wireless devices performing wireless communication was increased from 1 to 5, and the communication characteristics were examined.

  From the results shown in FIG. 19, it can be seen that when the number of sessions where buffering is started at the access point 330 exceeds 4, the delay and the packet error rate increase rapidly.

  Accordingly, buffering of transfer data may occur in the repeater (= access point 330) where the two lines shown in FIG. 18 intersect, which increases the delay time and packet loss in the repeater. That is, when the access point transmits a packet to the backbone network, there is a problem that the packet loss and the delay time are increased in the repeater when the amount of packets transmitted from the access point to the backbone network reaches a limit.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a repeater capable of suppressing an increase in delay time and packet error rate.

  Another object of the present invention is to provide a radio network system including a repeater capable of suppressing increases in delay time and packet error rate.

  Furthermore, another object of the present invention is to provide a program for causing a computer to execute processing capable of suppressing an increase in delay time and packet error rate.

  According to the present invention, the repeater is a repeater that relays wireless communication between a transmission source and a transmission destination, and includes a reception unit and a communication unit. The receiving means receives packets from p (p is a positive integer) wireless devices that are transmission sources. The communication means generates another relay packet by bundling m packets (m is an integer of 2 or more) received by the receiving means into one packet, and relays the wireless communication to the destination wireless device. Send the generated relay packet to

  Preferably, the m packets are packets received by the receiving unit within a predetermined time.

  According to the present invention, the wireless network system includes first and second repeaters, i (i is a positive integer) wireless devices, and j (j is a positive integer) wireless devices. Is provided. The second repeater transmits and receives packets to and from the first repeater by wireless communication. Each of the i wireless devices transmits and receives a packet by wireless communication via the first repeater. Each of the j wireless devices transmits and receives a packet by wireless communication via the second repeater. Then, the first repeater generates a first relay packet by bundling m (m is an integer of 2 or more) packets received from i wireless devices into one packet, 1 relay packet is transmitted to the second repeater. The second repeater generates a second relay packet by bundling n packets (n is an integer of 2 or more) received from j wireless devices into one packet, and generates the generated second relay packet. The relay packet is transmitted to the first repeater.

  Preferably, the first repeater performs wireless communication with i radio apparatuses using the first frequency and uses a second frequency different from the first frequency to communicate with the second repeater. Wireless communication with The second repeater performs wireless communication with the j wireless devices using the first frequency, and performs wireless communication with the first repeater using the second frequency.

  Preferably, the wireless network system further includes a third repeater. The third repeater relays the packet by wireless communication between the first repeater and the second repeater. The third repeater performs wireless communication with the first and second repeaters in the ad hoc mode.

  Preferably, the first repeater transmits the first relay packet by unicast. The second repeater transmits the second relay packet by unicast.

  Preferably, the first repeater transmits the first relay packet by broadcast. The second repeater transmits the second relay packet by broadcast.

  Furthermore, according to the present invention, a program for causing a computer to execute a program is that i (i is a positive integer) wireless devices that transmit and receive packets via the first repeater are connected via the second repeater. A program for causing a computer to execute processing in the first repeater when transmitting packets to j (j is a positive integer) wireless devices that transmit and receive packets, and the receiving means includes i wireless devices. A first step of receiving m (m is an integer of 2 or more) packets from the apparatus, and a packet generation unit bundles the m packets received by the reception unit in the first step into one packet. The second step of generating the relay packet and the third step of the communication means transmitting the relay packet generated by the packet generation means in the second step to the second repeater are compiled. A program to be executed by the over data.

  In the present invention, the repeater generates a relay packet by bundling a plurality of packets received from the wireless device, and relays the generated relay packet to another repeater. As a result, the rate of increase in transmission time required to transmit one packet is drastically reduced as compared to the case where a plurality of packets are relayed individually.

  Therefore, according to the present invention, an increase in delay time and packet error rate in a repeater that relays wireless communication can be suppressed.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic diagram of a wireless network system 100 using a wireless device according to an embodiment of the present invention. The wireless network system 100 includes wireless devices 101 to 10p and 111 to 11p, and access points 120, 130, 140, 150, 160, 170, and 180. The wireless network system 100 is a mesh network.

  Wireless devices 101 to 10p, 111 to 11p, and access points 120, 130, 140, 150, 160, 170, and 180 are arranged in a wireless communication space. The access points 120, 130, 140, 150, 160, 170, and 180 constitute a backbone network.

  The wireless devices 101 to 10p exist under the access point 120 and perform wireless communication with the access point 120 in the infrastructure mode using the frequency f1. In addition, the wireless devices 111 to 11p exist under the access point 140 and perform wireless communication with the access point 140 in the infrastructure mode using the frequency f1.

  Access points 120, 130, 140, 150, 160, 170, and 180 perform radio communication with each other in an ad hoc mode using frequency f2.

  In FIG. 1, only the wireless devices 101 to 10p and 111 to 11p existing under the access points 120 and 140 are shown, but actually, the wireless devices are also under the access points 130, 150, 160, 170, and 180. A wireless device is present.

  When the wireless devices 101 to 10p perform wireless communication with the wireless devices 111 to 11p, respectively, the access point 120 relays the packets received from the wireless devices 101 to 10p to the access point 140 by unicasting or broadcasting.

  When the access point 120 transmits a packet to the access point 140, the access points 130, 150, 160, 170, and 180 relay the packet from the access point 120.

  As a path for the access point 120 to transmit a packet to the access point 140, a path including the access point 120-access point 130-access point 140, a path including the access point 120-access point 150-access point 160-access point 140, There are various routes such as a route including the access point 120 -the access point 170 -the access point 180 -the access point 140.

  FIG. 2 is a schematic block diagram illustrating the configuration of the wireless devices 101 to 10p and 111 to 11p and the access points 120, 130, 140, 150, 160, 170, and 180 illustrated in FIG. The wireless device 101 includes an antenna 11, an input unit 12, an output unit 13, a user application 14, and a communication control unit 15.

  The antenna 11 receives data from the access point 120 via the wireless communication space, outputs the received data to the communication control unit 15, and transmits the data from the communication control unit 15 to the access point 120 via the wireless communication space. Send to.

  The input unit 12 receives a destination of a message and data input by an operator of the wireless device 101 and outputs the received message and destination to the user application 14. The output unit 13 displays a message according to control from the user application 14.

  The user application 14 generates data based on the message and destination from the input unit 12 and outputs the data to the communication control unit 15.

  The communication control unit 15 includes a plurality of modules that perform communication control in accordance with an ARPA (Advanced Research Projects Agency) Internet hierarchical structure. That is, the communication control unit 15 includes a wireless interface module 16, a MAC (Media Access Control) module 17, a packet receiving module 18, a buffer 19, an LLC (Logical Link Control) module 20, and an IP (Internet Protocol) module. 21, a packet connection module 22, a packet transfer module 23, a TCP module 24, and a UDP module 25.

  The wireless interface module 16 belongs to the physical layer, modulates / demodulates a transmission signal or a reception signal according to a predetermined rule, and transmits / receives a signal via the antenna 11.

  The MAC module 17 belongs to the MAC layer, executes the MAC protocol, and executes various functions described below.

  That is, the MAC module 17 broadcasts the Hello packet received from the upper layer via the wireless interface module 16.

  The MAC module 17 performs retransmission control of data (packets).

  The packet receiving module 18 belongs to the MAC layer. When the packet receiving module 18 is mounted on the access points 120, 130, 140, 150, 160, 170, 180, the wireless interface module 16 is connected to the wireless devices 101 to 10 p (or the wireless devices 111 to 111) via the antenna 11. 11p) collects the received packets and outputs the collected packets to the packet concatenation module 22.

  The buffer 19 belongs to the data link layer and temporarily stores packets.

  The LLC module 20 belongs to the data link layer, and executes the LLC protocol to connect and release a link with an adjacent wireless device.

  The IP module 21 belongs to the Internet layer and generates an IP packet. The IP packet includes an IP header and an IP data portion for storing a packet of a higher protocol. When the IP module 21 receives data from the TCP module 24 or the UDP module 25, the IP module 21 stores the received data in the IP data portion and generates an IP packet.

  Then, the IP module 21 outputs the IP packet to the packet transfer module 23.

  The packet concatenation module 22 belongs to the Internet layer, generates a relay packet by bundling a plurality of packets received from the packet receiving module 18 into one packet regardless of the destination of each packet, and forwards the generated relay packet to a packet. Output to module 23.

  The packet transfer module 23 transfers the packet received from the IP module 21, the packet received from another access point, and the packet received from the packet connection module 22 via the wireless interface module 16 and the antenna 11. In this case, the packet transfer module 23 transfers the packet by unicast or broadcast.

  When the packet transfer module 23 transfers a packet by unicast, the packet transfer module 23 incorporates an adjacency list indicating a list of links between the access point on which the packet transfer module 23 is mounted and an access point adjacent to the access point on which the packet transfer module 23 is mounted. The packet is transferred by unicast with reference to the built-in neighbor list. In this case, the packet transfer module 23 transfers the packet to all access points adjacent to the access point 120 (or the access point 140) while copying the relay packet.

  Note that the packet transfer module 23 transmits and receives Hello packets to and from adjacent access points to create an adjacent list.

  In the wireless network system 100, the access points 120 and 140 that relay packets transmitted by the subordinate wireless devices 101 to 10p and 111 to 11p bundle a plurality of packets received from the wireless devices 101 to 10p and 111 to 11p. Send to backbone network.

  Therefore, packet bundling will be described. FIG. 3 is a conceptual diagram showing packet bundling. When the wireless devices 101 to 10p are composed of three wireless devices 101 to 103 and the wireless devices 111 to 11p are composed of three wireless devices 111 to 113, the access point 120 receives packets PKT1 to PKT1 from the wireless devices 101 to 103, respectively. PKT3 is received.

  Then, the packet concatenation module 22 of the access point 120 generates the relay packet PKT_TF by bundling the packets PKT1 to PKT3 received from the wireless devices 101 to 103 into one packet.

  In this case, the packet concatenation module 22 bundles the packets PKT1 to PKT3 into one packet regardless of the destinations of the packets PKT1 to PKT3. In the wireless network system 100, since the wireless devices 101 to 103 perform wireless communication with the wireless devices 111 to 113, respectively, the destinations of the packets PKT1 to PKT3 transmitted by the wireless devices 101 to 103 are respectively wireless devices 111. ~ 113. That is, the destinations of the packets PKT1 to PKT3 are different from each other. Thus, even when the destinations of the packets PKT1 to PKT3 are different from each other, the packet concatenation module 22 of the access point 120 converts the packets PKT1 to PKT3 into one packet regardless of the destinations of the packets PKT1 to PKT3. A relay packet PKT_TF is generated by bundling.

  Further, the packet connection module 22 of the access point 120 generates the relay packet PKT_TF by bundling the packets PKT1 to PKT3 that have arrived within a certain time. This fixed time is set to 5 msec, for example.

  Then, the packet connection module 22 of the access point 120 does not wait for the elapse of a certain time if the packet size when a plurality of packets arrived before the certain time elapses reaches an MTU (Maximum Transfer Unit). When the packet size reaches the MTU, the bundled packet is output to the packet transfer module 23. Then, the packet transfer module 23 transfers the packet from the packet connection module 22.

  Further, the packet concatenation module 22 of the access point 120 bundles a plurality of packets that reach the predetermined time if the packet size when the plurality of packets that have arrived until the predetermined time is reached does not reach the MTU. The bundled packet is output to the packet transfer module 23.

  As described above, the packet size of the relay packet PKT_TF generated by bundling a plurality of packets is set to be equal to or smaller than the MTU. When the packet size of the relay packet PKT_TF generated by bundling a plurality of packets is equal to or larger than the MTU, This is to prevent the packet error rate from increasing.

  For example, when a G711 codec is used with VoIP and a 160-byte packet is generated at 20 msec intervals, a relay packet PKT_TF is generated by bundling about 5 packets.

When the wireless devices 111 to 113 transmit packets to the wireless devices 101 to 103, respectively, the access point 140, like the access point 120, bundles a plurality of packets PKT4 to PKT6 received from the wireless devices 111 to 113, and relays packets. PKT_TF is generated.
Note that the packet sizes of the packets PKT1 to PKT6 may be the same as each other or may be different from each other. Accordingly, the packet concatenation module 22 may generate a relay packet PKT_TF by bundling a plurality of packets having different packet sizes.
Each of the packets PKT1 to PKT6 may have a packet size of about MTU. When the packet concatenation module 22 receives one packet having such a large size, the packet concatenation module 22 bundles a plurality of packets received before receiving the one packet and outputs the bundled packets to the packet transfer module 23. Thereafter, one packet having a size of about MTU is output to the packet transfer module 23 alone.

  FIG. 4 is a schematic diagram when relay packets are relayed. In wireless network system 100, three access points 130, 150, and 170 are adjacent to access point 120, and three access points 130, 160, and 180 are adjacent to access point 140.

In the case of an application in which the packet delay time is limited, each of the access points 120, 130, 140, 150, 160, 170, 180 does not use a routing protocol, and each of the access points 120, 130, 140, 150, 160, 170, 180 The packet is bundled irrespective of the destination to generate a relay packet, and the generated relay packet is transmitted by unicast (see FIG. 4A).
This will be described in more detail. As described above, the access point 120 that has received the plurality of packets PKT1 to PKTp from the wireless devices 101 to 10p bundles the plurality of packets PKT1 to PKTp and generates the relay packet PKT_TF1. Then, the access point 120 unicasts the generated relay packet PKT_TF1 to the access points 130, 150, and 170 adjacent to itself.

  In this case, the packet transfer module 23 of the access point 120 copies the generated relay packet PKT_TF1 and transmits it to the three access points 130, 150, and 170 adjacent to the access point 120 by unicast.

  The access point 130 that has received the relay packet PKT_TF1 from the access point 120 transmits the received relay packet PKT_TF1 to the access points 120, 140, 150, 160, 170, and 180 adjacent thereto by unicast.

  In addition, the access point 150 that has received the relay packet PKT_TF1 from the access point 120 transmits the received relay packet PKT_TF1 to the access points 120, 130, and 160 adjacent thereto by unicast.

  Further, the access point 170 that has received the relay packet PKT_TF1 from the access point 120 transmits the received relay packet PKT_TF1 to the access points 120, 130, and 180 adjacent thereto by unicast.

  Then, the access point 160 that has received the relay packet PKT_TF1 from the access point 150 transmits the received relay packet PKT_TF1 to the access points 130, 140, and 150 adjacent thereto by unicast.

  In addition, the access point 180 that has received the relay packet PKT_TF1 from the access point 170 transmits the received relay packet PKT_TF1 to the access points 130, 140, and 170 adjacent thereto by unicast.

  In this way, the relay packet PKT_TF1 is relayed from the access point 120 to the access point 140 without using a routing protocol.

  The relay packet PKT_TF2 generated by bundling a plurality of packets transmitted by the wireless devices 111 to 11p is also relayed from the access point 140 to the access point 120 by unicast, similarly to the relay packet PKT_TF1.

  If there is a delay time constraint that is more severe than the allowable delay time when relaying a relay packet by unicast, or if the number of adjacent access points is large, the access points 120, 130, 140, 150, 160 , 170, 180 each generate a relay packet by bundling a plurality of packets from wireless devices existing under its control regardless of the destination, and transmits the generated relay packet by broadcast ((b in FIG. 4). )reference).

  As described above, in the wireless network system 100, the delay time between end-to-end (that is, the wireless devices 101 to 10p and the wireless devices 111 to 11p) is restricted or the number of access points adjacent to each access point. The relay packet is relayed by appropriately selecting unicast or broadcast.

  When relay packets are relayed by the above-described unicast or broadcast, each access point 120, 130, 140, 150, 160, 170, 180 has its own destinations for a plurality of packets constituting the received relay packet. It is determined whether or not the wireless device is under the control of the wireless device, and when the destinations of the plurality of packets are wireless devices that are under the control of the wireless device, the plurality of packets are transmitted to the wireless device under the control of the wireless device. . As a result, a wireless device existing under each access point 120, 130, 140, 150, 160, 170, 180 can perform two-way wireless communication with a wireless device existing under another access point. .

  FIG. 5 is a schematic diagram of wireless communication when a plurality of packets are bundled, and FIG. 6 is a schematic diagram of wireless communication when a plurality of packets are not bundled. As described above, the packet is relayed from the access point 120 (or the access point 140) to the access point 140 (or the access point 120) by unicast or broadcast. However, in FIG. 5 and FIG. For this reason, a schematic diagram when a packet is relayed between the access point 120 and the access point 140 via the access point 130 is shown.

  When the wireless devices 101 to 103 perform bidirectional wireless communication with the wireless devices 111 to 113 via the access points 120, 130, and 140, the wireless devices 101 to 103 access the packets PKT1 to PKT3 at the frequency f1, respectively. The wireless devices 111 to 113 transmit the packets PKT4 to PKT6 to the access point 140 at the frequency f1, respectively.

  Then, the access point 120 bundles the packets PKT <b> 1 to PKT <b> 3 received from the wireless devices 101 to 103 within a predetermined time to generate the relay packet PKT_TF <b> 1, and transmits the generated relay packet PKT_TF <b> 1 to the access point 130.

  Further, the access point 140 bundles the packets PKT4 to PKT6 received from the wireless devices 111 to 113 within a predetermined time to generate the relay packet PKT_TF2, and transmits the generated relay packet PKT_TF2 to the access point 130.

  Accordingly, when performing wireless communication by bundling a plurality of packets, there are four relay packets PKT_TF1 and PKT_TF2 per packet generation time in the backbone network constituted by the access points 120, 130, and 140 (FIG. 5). reference).

  On the other hand, the access point 120 transmits the packets PKT1 to PKT3 from the wireless devices 101 to 103 to the access point 130 without bundling, and the access point 140 does not bundle the packets PKT4 to PKT6 from the wireless devices 111 to 113. When transmitting to the backbone network, there are 12 packets PKT1 to PKT6 per packet generation time in the backbone network constituted by the access points 120, 130, and 140 (see FIG. 6).

  Therefore, when normal unicast or broadcast is used, the number of packets existing in the backbone network per packet generation time can be reduced from 12 to 4 by bundling a plurality of packets.

  As a result, an increase in delay time and packet error rate at the access point 130 can be suppressed.

  FIG. 7 is a diagram illustrating the relationship between the transmission time and the number of packets. In FIG. 7, the vertical axis represents the transmission time required to transmit one packet, and the horizontal axis represents the number of packets. The bar graph BG1 indicates the transmission time for each packet number when a plurality of packets are bundled, and the bar graph BG2 indicates the transmission time for each packet number when a plurality of packets are not bundled.

  FIG. 7 shows a case where IEEE802.11b is assumed for a case where a plurality of packets each having 100 bytes are bundled and a case where a plurality of packets each having 100 bytes are separately transmitted. The result of estimating the transmission time required to transmit the packet of is shown.

  When a plurality of packets are transmitted separately, the transmission time required to transmit one packet increases as the number of packets increases (see bar graph BG2). On the other hand, when a plurality of packets are bundled and transmitted, the transmission time required to transmit one packet is only slightly increased with respect to the number of packets (see bar graph BG1).

  As described above, the transmission time required for transmitting one packet by bundling and transmitting a plurality of packets does not greatly increase with respect to the number of packets. The overhead of IEEE802.11b is the actual transmission of packets. This is because the time is so large that it cannot be ignored.

  Therefore, it can be seen that the effect of reducing the increase in delay time caused by bundling and transmitting a plurality of packets is extremely high.

  In particular, assuming a real-time application such as VoIP, a process for bundling and transmitting a plurality of packets at intervals of 5 msec is implemented in the access points 120 and 140, and the wireless devices 101 to 10p are respectively wireless devices. The average delay time when performing bidirectional wireless communication with 111-11p was measured.

  In this case, the number of sessions was changed from 1 to 5. Each of access points 120, 130, and 140 performs unicast wireless communication.

  FIG. 8 is a diagram illustrating the relationship between the average delay time and the number of sessions. In FIG. 8, the vertical axis represents the average delay time, and the horizontal axis represents the number of sessions. A bar graph BG3 indicates the average delay time for each number of sessions when a plurality of packets are bundled and transmitted, and a bar graph BG4 indicates the average delay time for each number of sessions when a plurality of packets are individually transmitted.

  When a plurality of packets are individually transmitted and the number of sessions exceeds “4”, the average delay time increases rapidly (see bar graph BG4). On the other hand, when a plurality of packets are bundled and transmitted, even if the number of sessions increases from “1” to “5”, the average delay time hardly increases.

  Table 1 shows the packet error rate with respect to the number of sessions.

  When a plurality of packets are individually transmitted, when the number of sessions exceeds “4”, the packet error rate rapidly increases (see “Conventional method” in Table 1). On the other hand, when a plurality of packets are bundled and transmitted, even if the number of sessions increases from “1” to “5”, the packet error rate is less than 1% and hardly increases (“present invention” in Table 1). reference).

Thus, by bundling and transmitting a plurality of packets, the average delay time and the packet error rate hardly increase even when the number of sessions exceeds “4”. The number of sessions = 4 is the number of sessions in which packet buffering is started in the access point 130 that relays wireless communication between the access points 120 and 140 (see FIG. 18).
Therefore, by bundling and transmitting a plurality of packets, even if the access point 130 that relays wireless communication in the backbone network exceeds the number of sessions for starting packet buffering, the increase in average delay time and packet error rate is suppressed. It has been demonstrated that it can be done.

  FIG. 9 is a flowchart for explaining the operation of wireless communication in the wireless network system 100. In FIG. 9, an operation in which the wireless devices 101 to 10p transmit packets to the wireless devices 111 to 11p via the access points 120, 130, and 140 will be described.

  When a series of operations is started, radio apparatuses 101 to 10p generate packets PKT1 to PKTp, respectively, and transmit the generated packets PKT1 to PKTp to access point 120 at frequency f1. That is, the wireless devices 101 to 10p transmit the packets PKT1 to PKTp to the access point 120 in the infrastructure mode (step S1).

  The access point 120 receives the packets PKT1 to PKTp from the radio apparatuses 101 to 10p at the frequency f1 (step S2), and bundles the received packets PKT1 to PKTp into one packet to generate a relay packet PKT_TF1. (Step S3). Then, the access point 120 transmits the generated relay packet PKT_TF1 to the access point 130 by unicast at the frequency f2 (step S4).

  Access point 130 relays relay packet PKT_TF1 from access point 120 to access point 140 at frequency f2. That is, the access point 130 relays the relay packet PKT_TF1 to the access point 140 in the ad hoc mode (step S5).

  Thereafter, the access point 140 receives the relay packet PKT_TF1 at the frequency f2 from the access point 130 (step S6). Then, the access point 140 extracts the packets PKT1 to PKTp from the received relay packet PKT_TF1, and transmits the extracted packets PKT1 to PKTp to the radio apparatuses 111 to 11p at the frequency f1, respectively. That is, the access point 140 transmits the wireless devices 111 to 11p to the wireless devices 111 to 11p in the infrastructure mode (step S7).

  Then, the wireless devices 111 to 11p receive the packets PKT1 to PKTp at the frequency f1, respectively. That is, the wireless devices 111 to 11p receive packets addressed to themselves from the access point 140 in the infrastructure mode (step S8). Thus, a series of operations is completed.

  Note that the operation in which the wireless devices 111 to 11p transmit packets to the wireless devices 101 to 10p via the access points 140, 130, and 120 is also performed according to the flowchart shown in FIG.

  In this case, the wireless devices 111 to 11p transmit packets PKT1 to PKTp to the access point 140 at the frequency f1, respectively, and the access point 140 bundles a plurality of packets PKT1 to PKTp from the wireless devices 111 to 11p and relays the packets. PKT_TF2 is generated, and the generated relay packet PKT_TF2 is transmitted to the access point 130 at the frequency f2.

  Therefore, when the operations of the wireless devices 111 to 11p transmitting packets to the wireless devices 101 to 10p are performed according to the flowchart shown in FIG. 9, in the above description, the wireless devices 101 to 10p are replaced with the wireless devices 111 to 11p, The access point 120 may be replaced with the access point 140, the access point 140 may be replaced with the access point 120, the wireless devices 111 to 11p may be replaced with the wireless devices 101 to 10p, and the relay packet PKT_TF1 may be replaced with the relay packet PKT_TF2.

  In the flowchart shown in FIG. 9, steps S2 to S4 constitute a “program for causing a computer to execute processing in the repeater” according to the present invention. And the program which consists of step S2-step S4 is performed with the personal computer shown in FIG. FIG. 10 is a schematic block diagram of a personal computer. The personal computer 90 includes a data bus BS, a CPU (Central Processing Unit) 91, a RAM (Random Access Memory) 92, a ROM (Read Only Memory) 93, a serial interface 94, and a terminal 95.

  CPU91 reads the program stored in ROM93 via data bus BS. Further, the CPU 91 stores a program acquired via the serial interface 94, the terminal 95, and the Internet network in the ROM 93.

  The RAM 92 is a work memory used when the CPU 91 performs various processes. The ROM 93 stores programs and the like. The serial interface 94 exchanges data between the data bus BS and the terminal 95. The terminal 95 is a terminal for connecting the personal computer 90 to a modem (not shown) with a cable.

  In response to a program execution request input via the terminal 95 and the serial interface 94, the CPU 91 reads out the program from the ROM 93 via the data bus BS and executes the read program. By executing this program, the CPU 91 in the access point 120 receives a plurality of packets PKT1 to PKTp from the wireless devices 101 to 10p at the frequency f1 (see step S2), and bundles and relays the received packets PKT1 to PKTp. A packet PKT_TF1 is generated (see step S3). Then, the CPU 91 in the access point 120 unicasts or broadcasts the generated relay packet PKT_TF1 at the frequency f2 (see step S4).

  When unicasting the relay packet PKT_TF1, the CPU 91 in the access point 120 copies the generated relay packet PKT_TF1 in accordance with the number of relay destination access points, and stores the copied relay packet PKT_TF1 in the RAM 92.

  In this case, if the number of relay destination access points is S (S is an integer equal to or greater than 2), the CPU 91 in the access point 120 copies S-1 relay packets PKT_TF1 and stores them in the RAM 92.

  Then, the CPU 91 in the access point 120 relays the relay packet PKT_TF1 to one access point, and then sequentially reads the S-1 relay packets PKT_TF1 stored in the RAM 92 and sequentially relays to the S-1 access points. To do.

  The CPU 91 in the access points 130, 140, 150, 160, 170, and 180 also bundles a plurality of packets from the wireless devices existing under the same by the same operation as the CPU 91 in the access point 120 or unicasts them to the relay destination access point. Broadcast.

  In the present invention, the CPU 91 reads a program from the ROM 93 via the data bus BS in response to a program execution request input via the terminal 95 and the serial interface 94, and executes the read program. By executing this program, the CPU 91 that receives the plurality of packets PKT1 to PKTp from the wireless devices 101 to 10p at the frequency f1 constitutes a “reception unit” and bundles the plurality of packets PKT1 to PKTp received by the reception unit. The CPU 91 that generates the relay packet PKT_TF1 constitutes “packet generation means”, and the CPU 91 that unicasts or broadcasts the relay packet PKT_TF1 generated by the packet generation means at the frequency f2 constitutes “communication means”.

  Further, the CPU 91 that copies S-1 relay packets PKT_TF1 constitutes “duplicating means”, and the RAM 92 that stores S-1 relay packets PKT_TF1 constitutes “storage means”. The CPU 91 that sequentially reads one relay packet PKT_TF1 and sequentially relays it to S-1 access points constitutes “communication means”.

[Modification 1]
In the case of an application that allows a relatively long delay time, each of the access points 120, 130, 140, 150, 160, 170, 180 has a buffer for each access point adjacent to the access point 120, 130, 140, 150, 170, 180. May be transmitted in a bundle.

The application that allows a relatively long delay time is, for example, chat. The relatively long delay time means a delay time longer than a reference value (= second order delay).
FIG. 11 is a schematic block diagram showing the configuration of the access points 120, 130, 140, 150, 160, 170, 180 in the first modification. In the first modification, each of the access points 120, 130, 140, 150, 160, 170, 180 includes the access point 120A shown in FIG. The access point 120 is the same as the wireless device 101 except that the communication control unit 15 of the wireless device 101 shown in FIG.
The communication control unit 15A is obtained by replacing the packet connection module 22 of the communication control unit 15 shown in FIG. 2 with the packet connection module 22A, and adding a routing table 26, a routing daemon 27, and a buffer 240. Same as 15.
In the access point 120A, the packet reception module 18 outputs the collected packets to the routing daemon 27.
The packet concatenation module 22A bundles a plurality of packets read from a buffer provided for each destination of the packet and outputs the bundle to the packet transfer module 23 by a method described later.
The routing table 26 belongs to the Internet layer and stores path information in association with each transmission destination, as will be described later.

The routing daemon 27 belongs to the process / application layer, monitors the execution state of other communication control modules, and processes requests from other communication control modules.
The routing daemon 27 calculates an optimum route and dynamically creates the routing table 26 in the Internet layer.
The buffer 240 belongs to the Internet layer, and stores the packets received from the packet receiving module 18 classified for each destination.
In the first modification, when the wireless devices 101 to 10p perform wireless communication with the wireless devices 111 to 11p, respectively, the access point 120 searches for a route to the access point 140, and receives a plurality of received from the wireless devices 101 to 10p. The packets are bundled and relayed to the access point 140.
In this case, for example, the access point 120 searches for a route to the access point 140 according to the OLSR protocol. The OLSR protocol is a table-driven routing protocol, and is a protocol for exchanging route information using a Hello message and a TC (Topology Control) message to create a routing table.

  FIG. 12 is a configuration diagram of a packet PKT in the OLSR protocol. The packet PKT includes a packet header PHD and message headers MHD1, MHD2,. The packet PKT is transmitted / received using the port number 698 of the UDP module 25.

  The packet header PHD includes a packet length and a packet sequence number. The packet length consists of 16-bit data and represents the number of bytes of the packet. The packet sequence number consists of 16-bit data and is used to distinguish which packet is new. The packet sequence number is incremented by “1” every time a new packet is generated. Therefore, the larger the packet sequence number, the newer the packet PKT.

  Each of the message headers MHD1, MHD2,... Includes a message type, a valid time, a message size, a source address, a TTL, a hop count, a message sequence number, and a message.

  The message type is composed of 8-bit data and represents the type of message written in the message body, and 0 to 127 are reserved. The valid time consists of 8-bit data, and represents the time when this message must be managed after reception. The valid time is composed of a mantissa part and an exponent part.

  The message size consists of 16-bit data and represents the length of the message. The source address is made up of 32-bit data and represents the wireless device that generated the message. The TTL is composed of 8-bit data and specifies the maximum number of hops to which a message is transferred. The TTL is decremented by “1” when the message is transferred. If the TTL is “0” or “1”, the message is not transferred. The number of hops consists of 8-bit data and represents the number of hops from the message generation source. The number of hops is initially set to “0” and is incremented by “1” every time it is transferred. The message sequence number consists of 16-bit data and represents an identification number assigned to each message. The message sequence number is incremented by “1” every time a message is created. The message is a message to be transmitted.

  In the OLSR protocol, various messages are transmitted and received using the packet PKT having the configuration shown in FIG.

  FIG. 13 is a configuration diagram of the routing table 26 shown in FIG. The routing table 26 includes a transmission destination, a next access point, and a hop number. The transmission destination, the next access point, and the number of hops are associated with each other. “Destination” represents the IP address of a destination access point. “Next access point” represents the IP address of the access point to be transmitted next when the packet PKT is transmitted to the transmission destination. “Hop number” represents the number of hops to the destination. For example, in FIG. 1, when wireless communication is performed between the access point 120 and the access point 140 through the route of the access point 120 -the access point 130 -the access point 140, the number of hops in the routing table 26 of the access point 120 is , “2” is stored.

  The creation of the routing table 26 according to the OLSR protocol will be described in detail. When creating the routing table 26, the access points 120, 130, 140, 150, 160, 170, and 180 transmit and receive Hello messages and TC messages.

  The Hello message is periodically transmitted for the purpose of distributing information held by each access point 120, 130, 140, 150, 160, 170, 180. By receiving this Hello message, each access point 120, 130, 140, 150, 160, 170, 180 can collect information on neighboring access points, and what kind of access points exist in the vicinity of itself. Recognize

  In the OLSR protocol, each access point 120, 130, 140, 150, 160, 170, 180 manages local link information. The Hello message is a message for constructing and transmitting the local link information. The local link information includes “link set”, “adjacent access point set”, “two-hop adjacent access point set and link set to those access points”, “MPR (Multipoint Relay) set”, and “MPR selector set”. including.

  A link set is a link to a set of access points (adjacent access points) through which radio waves directly reach, and each link is expressed by an effective time of a set of addresses between two access points. The valid time is also used to indicate whether the link is unidirectional or bidirectional.

  The adjacent access point set is configured by the address of each adjacent access point, the aggressiveness (Willingness) of retransmission of the access point, and the like. The 2-hop adjacent access point set represents a set of access points adjacent to the adjacent access point.

  The MPR set is a set of access points selected as MPR. Note that MPR means that each packet PKT is transmitted to all access points 120, 130, 140, 150, 160, 170, 180 of the wireless network system 100, and each access point 120, 130, 140, 150, 160, 170 and 180 select a relay access point so that a packet PKT can be transmitted to all access points 120, 130, 140, 150, 160, 170 and 180 by transmitting and receiving one packet PKT only once. .

  The MPR selector set represents a set of access points that have selected themselves as MPRs.

  The process of establishing local link information is generally as follows. In the early stage, each access point 120, 130, 140, 150, 160, 170, 180 transmits a Hello message containing its own address to an adjacent access point in order to inform the existence of the Hello message. . All of the access points 120, 130, 140, 150, 160, 170, 180 do this, and each access point 120, 130, 140, 150, 160, 170, 180 has what address around it. Find out if there is an access point you have. In this way, a link set and an adjacent access point set are constructed.

  The constructed local link information is continuously sent again by a Hello message again. By repeating this, it is gradually clarified whether each link is bidirectional or what access point exists ahead of the adjacent access point. Each access point 120, 130, 140, 150, 160, 170, 180 stores local link information that is gradually built up in this way.

  Further, information on MPR is also periodically transmitted by a Hello message and notified to each access point 120, 130, 140, 150, 160, 170, 180. Each access point 120, 130, 140, 150, 160, 170, 180 selects several access points from neighboring access points as an MPR set as an access point requesting retransmission of the packet PKT transmitted by itself. is doing. Then, since the information on the MPR set is transmitted to the adjacent access point by the Hello message, the access point that has received the Hello message uses the set of access points that it has selected as the MPR as the “MPR selector set”. to manage. In this way, each access point 120, 130, 140, 150, 160, 170, 180 can immediately recognize from which access point the packet PKT received should be retransmitted.

  When a local link set is established at each access point 120, 130, 140, 150, 160, 170, 180 by transmission / reception of a Hello message, a TC message for notifying the topology of the entire wireless network system 100 is displayed. 130, 140, 150, 160, 170, 180. This TC message is periodically transmitted by all access points selected as MPR. Since the TC message includes a link between each access point and the MPR selector set, all the access points 120, 130, 140, 150, 160, 170, 180 of the wireless network system 100 The MPR set and all the MPR selector sets can be known, and the topology of the entire radio network system 100 can be known based on all the MPR sets and all the MPR selector sets. Each access point 120, 130, 140, 150, 160, 170, 180 calculates the shortest path using the topology of the entire wireless network system 100, and creates a route table based on it.

Each access point 120, 130, 140, 150, 160, 170, 180 frequently exchanges TC messages separately from the Hello message. MPR is also used for exchanging TC messages.
The UDP module 25 of each access point 120, 130, 140, 150, 160, 170, 180 transmits and receives the above-described Hello message and TC message, and the routing daemon 27 transmits the Hello message and TC message received by the UDP module 25. Based on the topology of the entire wireless network system 100, the shortest path is calculated based on the topology of the entire wireless network system 100, and the routing table 26 shown in FIG. 13 is dynamically created based on the calculated shortest path.

FIG. 14 is a conceptual diagram when a plurality of packets are bundled for each buffer. FIG. 15 is a diagram illustrating a routing table of the access point 120. FIG. 14 shows a case where the access point 120 has three buffers corresponding to the three access points 130, 150, and 170 adjacent to the access point 120. Further, the access point 120 holds a routing table 26A shown in FIG.
A buffer 240 illustrated in FIG. 11 includes buffers 241 to 243. Buffers 241 to 243 are provided corresponding to access points 130, 150, and 170, respectively. That is, the buffer 241 stores a packet to be relayed to the access point 130, the buffer 242 stores a packet to be relayed to the access point 150, and the buffer 243 stores a packet to be relayed to the access point 170.

  When receiving the packet from the wireless devices 101 to 10p, the routing daemon 27 of the access point 120 determines to which of the access points 130, 150, and 170 the received packet should be relayed, and receives the packet according to the determination result. The packet is stored in one of the buffers 241 to 243.

  Since the routing daemon 27 of the access point 120 knows which access point the wireless device with which the wireless devices 101 to 10p communicate wirelessly exists, the packet received from the wireless devices 101 to 10p. To which access point should be relayed.

  In this case, the routing daemon 27 of the access point 120 stores the packets PKT31, PKT32, ... in the buffer 241, stores the packets PKT41, PKT42, ... in the buffer 242, and the packets PKT51, PKT52, ... Is stored in the buffer 243.

  Then, the routing daemon 27 of the access point 120 generates a relay packet PKT_TF3 by bundling a plurality of packets PKT31, PKT32,... Stored in the buffer 241, and generates a plurality of packets PKT41, PKT42,. Are combined to generate a relay packet PKT_TF4, and a plurality of packets PKT51, PKT52,... Stored in the buffer 243 are combined to generate a relay packet PKT_TF5.

  Then, referring to the routing table 26A, when the destination is the access point 130 or the access point 140, the relay packet PKT_TF3 is transmitted to the access point 130. Therefore, the routing daemon 27 of the access point 120 uses the relay packet PKT_TF3. The packet transfer module 23 is controlled to transmit to the access point 130 or the access point 140.

  Similarly, the routing daemon 27 of the access point 120 controls the packet transfer module 23 to transmit the relay packet PKT_TF4 to the access point 150 or the access point 160, and transmits the relay packet PKT_TF5 to the access point 170 or the access point 180. The packet transfer module 23 is controlled as follows.

  When the packet transfer module 23 of the access point 120 receives the relay packet PKT_TF3 from the packet concatenation module 22A, it adds the IP address of the access point 130 or the IP address of the access point 140 to the relay packet PKT_TF3 and adds the IP address of the access point 130 or 140. Send to.

  When the packet transfer module 23 of the access point 120 receives the relay packet PKT_TF4 from the packet concatenation module 22A, it adds the IP address of the access point 150 or the IP address of the access point 160 to the relay packet PKT_TF4 to access the access point 150 or access. Send to point 160.

  Further, when receiving the relay packet PKT_TF5 from the packet concatenation module 22A, the packet transfer module 23 of the access point 120 adds the IP address of the access point 170 or the IP address of the access point 180 to the relay packet PKT_TF5 to access the access point 170 or access. Transmit to point 180.

  As a result, the relay packet is relayed together with the routing protocol.

  The other access points 130, 140, 150, 160, 170, 180 also relay relay packets using a routing protocol in the same manner as the access point 120.

[Modification 2]
In the above, when each access point 120, 130, 140, 150, 160, 170, 180 receives a plurality of packets from a subordinate wireless device, it generates a relay packet by unconditionally bundling the received plurality of packets. However, in the present invention, the present invention is not limited to this, and each access point 120, 130, 140, 150, 160, 170, 180 has its own packet transmission amount per unit time, delay time and packet error rate A relay packet may be generated by bundling a plurality of packets when reaching a threshold value that is the maximum packet transmission amount that increases.

  In this case, the IP module 21 of each of the access points 120, 130, 140, 150, 160, 170, and 180 performs wireless communication using a certain route among the routes stored in the routing table 26. A cache of the routing table 26, which is a copy of wireless communication, is created, and the created cache is held in a memory (not shown).

  In addition, the routing daemon 27 of each access point 120, 130, 140, 150, 160, 170, 180 performs wireless communication when wireless communication is performed using a certain route among the routes stored in the routing table 26. Referring to the cache of the routing table 26 which is a copy of the packet, the packet transmission amount per unit time at the access point 120, 130, 140, 150, 160, 170, 180 on which the self is mounted is calculated. The calculated packet transmission amount includes the number of packets per unit time that each access point 120, 130, 140, 150, 160, 170, 180 receives and transfers from other access points, and each access point 120, 130,140,150,160,170,180 consists of the sum with the packet number per unit time which starts transmission.

  Then, when the calculated packet transmission amount reaches the threshold value or more, the routing daemon 27 of each access point 120, 130, 140, 150, 160, 170, 180 generates a relay packet by bundling a plurality of packets, The generated relay packet is transmitted.

  FIG. 16 is a diagram illustrating an example of the cache of the routing table 26. Note that the cache CACHE shown in FIG. 16 includes only items related to the present invention among the items constituting the actual cache of the routing table 26.

  The cache CACHE of the routing table 26 includes an Face, a Destination, a Use, and a Source. “Interface” represents an interface, “Destination” represents a transmission destination, “Use” represents a packet transmission amount per unit time, and “Source” represents a transmission source.

  The cache CACHE is a cache of the routing table 26 in the access point 120, eth1 represents Ethernet (“Ethernet” is a registered trademark), the address “4009000A” represents the wireless device 111, and the address “ 3E090C0A ”represents the wireless device 101, the address“ 9F090C0A ”represents the wireless device 112, the address“ 99090D0A ”represents the wireless device 102, the address“ 99090C0B ”represents the wireless device 11p, and the address“ 99090C0A ” Represents the wireless device 10p.

  When the wireless devices 101 to 10p perform two-way wireless communication with the wireless devices 111 to 11p, respectively, the access points 120 and 140 receive a plurality of packets received from the wireless devices existing under their control as shown in FIG. Are relayed individually.

  In such a situation, the routing daemon 27 of the access point 120 refers to the cache CACHE (see FIG. 16) of the routing table 26A, and the packet relayed by the access point 120 in the wireless communication between the wireless device 101 and the wireless device 111. A transmission amount (= 20823 / second), a packet transmission amount (= 7122 / second) relayed by the access point 120 in wireless communication between the wireless device 102 and the wireless device 112, and between the wireless device 10p and the wireless device 11p. The sum W (= 28585 / second) with the packet transmission amount (= 640 / second) relayed by the access point 120 in wireless communication is calculated. In this case, the packet transmission amount (= 20823 / second) in the wireless communication between the wireless device 101 and the wireless device 111, and the packet transmission amount (= 7122 / second) in the wireless communication between the wireless device 102 and the wireless device 112. The sum (= 28585 / second) of the packet transmission amount (= 640 / second) in the wireless communication between the wireless device 10p and the wireless device 11p is the maximum at which the delay time and the packet error rate at the access point 120 do not increase. It is assumed that the threshold value Wth, which is the packet transmission amount per unit time (number / second), is reached.

  Then, the routing daemon 27 of the access point 120 determines whether or not the calculated packet transmission amount W has reached the threshold value Wth or more, and determines that the packet transmission amount W has reached the threshold value Wth or more. At this time, a plurality of packets received from the wireless devices 101 to 10p are bundled to generate a relay packet, and the generated relay packet is transmitted to the access point 140.

  Similarly to the access point 120, the access point 140 calculates the packet transmission amount W per unit time in itself, and when the calculated packet transmission amount W per unit time reaches the threshold Wth or more, the wireless device 111. A relay packet is generated by bundling a plurality of packets received from ˜11p, and the generated relay packet is transmitted to the access point 120.

  Thereby, the increase in the delay time and the packet error rate at the access points 120 and 140 can be suppressed.

  In the above description, the object of wireless communication has been described as sound data. However, in the present invention, the present invention is not limited to this, and the object of wireless communication may be game data other than sound data, such as image data. There may be.

  In the above, the frequency of wireless communication performed between the access points 120, 130, 140, 150, 160, 170, and 180 is between the wireless devices 101 to 10p and the access point 120, and between the wireless devices 111 to 11p. Although it has been described that the frequency is different from the frequency of wireless communication performed with the access point 140, the present invention is not limited to this, and wireless communication performed between the access points 120, 130, 140, 150, 160, 170, and 180 is not limited thereto. The frequency of communication may be the same as the frequency of wireless communication performed between the wireless devices 101 to 10p and the access point 120 and between the wireless devices 111 to 11p and the access point 140.

  Further, when a packet transmission amount W per unit time reaches a threshold value Wth or more, when a plurality of packets are bundled and relayed, data transmission at each access point 120, 130, 140, 150, 160, 170, 180 is performed. When the interval falls below the threshold value, a plurality of packets may be bundled and relayed so that the packet transmission amount per unit time becomes smaller than the threshold value Wth. When the communication load at each access point 120, 130, 140, 150, 160, 170, 180 reaches a threshold value or more, a plurality of packets may be bundled to relay the packets. Therefore, in the present invention, the packet transmission amount W per unit time equal to or greater than the threshold value Wth and the packet transmission interval equal to or less than the threshold value constitute a “communication load”.

  The threshold value is generally “the maximum communication load per unit time at which the delay time and the packet error rate at each access point 120, 130, 140, 150, 160, 170, 180 do not increase”. Defined.

  Further, when the packet transmission interval is used as a criterion for determining whether or not to perform a process of bundling a plurality of packets and relaying the packet, the routing daemon 27 calculates the reciprocal of the packet transmission amount W calculated by the above-described method. Thus, the packet transmission interval is obtained.

  Note that the packet reception module 18 of the access point 120 that receives packets from the wireless devices 101 to 10p or the packet reception module 18 of the access point 140 that receives packets from the wireless devices 111 to 11p constitutes a “reception unit”.

  The packet concatenation modules 22 and 22A for bundling a plurality of packets to generate relay packets and the packet transfer module 23 for transferring the packets generated by the packet concatenation modules 22 and 22A to other repeaters are “communication means”. Configure.

  Further, the access point 120 constitutes a “first repeater”, the access point 140 constitutes a “second repeater”, and the access point 130 constitutes a “third repeater”.

  Further, the wireless devices 101 to 10p constitute “i (i is a positive integer) wireless devices”, and the wireless devices 111 to 11p constitute “j (j is a positive integer) wireless devices”. To do.

  Further, the relay packet PKT_TF1 constitutes a “first relay packet”, and the relay packet PKT_TF2 constitutes a “second relay packet”.

  Further, in the present invention, the access point 120 generally bundles m packets (m is an integer of 2 or more) received from i wireless devices, regardless of the transmission destination, and provides one relay packet. In general, the access point 140 bundles n packets (n is an integer equal to or larger than 2) received from j wireless devices and bundles one relay packet regardless of the transmission destination. It only has to be generated.

  In addition, m and n may coincide with each other or may not coincide with each other. Also, i and m may or may not match each other, and j and n may or may not match each other. In this case, m packets or n packets are composed of packets transmitted to at least two transmission destinations.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a repeater capable of suppressing an increase in delay time and packet error rate. The present invention is also applied to a radio network system including a repeater that can suppress an increase in delay time and packet error rate. Furthermore, the present invention is applied to a program for causing a computer to execute processing capable of suppressing an increase in delay time and packet error rate.

1 is a schematic diagram of a wireless network system using a wireless device according to an embodiment of the present invention. It is a schematic block diagram which shows the structure of the radio | wireless apparatus and access point shown in FIG. It is a conceptual diagram which shows the bundling of a packet. It is a schematic diagram when a relay packet is relayed. It is a schematic diagram of wireless communication when a plurality of packets are bundled. It is a schematic diagram of the radio | wireless communication when not bundling a some packet. It is a figure which shows the relationship between transmission time and the number of packets. It is a figure which shows the relationship between average delay time and the number of sessions. 5 is a flowchart for explaining an operation of wireless communication in a wireless network system. It is a schematic block diagram of a personal computer. It is a schematic block diagram which shows the structure of the access point in the modification 1. It is a block diagram of the packet PKT in OLSR protocol. It is a block diagram of the routing table shown in FIG. It is a conceptual diagram in the case of bundling a plurality of packets for each buffer. It is a figure which shows the routing table of an access point. It is a figure which shows an example of the cache of a routing table. It is a schematic diagram of a mesh type network for estimating the limit of the amount of packets sent from an access point to a backbone network. It is a figure which shows the relationship between the maximum waiting time and transfer time interval, and the number of sessions. It is a figure which shows the relationship between a delay and a packet error rate, and the number of sessions.

Explanation of symbols

  11 antenna, 12 input unit, 13 output unit, 14 user application, 15, 15A communication control unit, 16 wireless interface module, 17 MAC module, 18 packet reception module, 19 buffer, 20 LLC module, 21 IP module, 22 packet connection Module, 23 Packet transfer module, 24 TCP module, 25 UDP module, 26, 26A Routing table, 27 Routing daemon, 90 Personal computer, 91 CPU, 92 RAM 93 ROM, 94 Serial interface, 95 terminal, 101-10p, 111- 11p, 311-31p wireless device, 100, 300 wireless network system, 120, 130, 140, 150, 160, 17 0, 180, 320, 330, 340 access point, 240-243 buffer.

Claims (8)

A relay that relays wireless communication between a source and a destination,
Receiving means for receiving packets from p (p is a positive integer) number of wireless devices as the transmission source;
A relay packet is generated by bundling m packets (m is an integer of 2 or more) received by the receiving unit into one packet, and the relay device relays wireless communication to the transmission destination wireless device. A repeater comprising communication means for transmitting the generated relay packet.   The repeater according to claim 1, wherein the m packets are packets received by the receiving unit within a predetermined time. A first repeater;
A second repeater for transmitting and receiving packets to and from the first repeater by wireless communication;
I (i is a positive integer) wireless devices each transmitting and receiving packets via the first repeater via wireless communication;
Each including j (j is a positive integer) wireless devices that transmit and receive packets via wireless communication via the second repeater,
The first repeater generates a first relay packet by bundling m (m is an integer of 2 or more) packets received from the i wireless devices into one packet, 1 relay packet is sent to the second relay,
The second repeater generates a second relay packet by bundling n packets (n is an integer of 2 or more) received from the j radio devices into one packet, A wireless network system that transmits two relay packets to the first repeater. The first repeater performs wireless communication with the i wireless devices using a first frequency and uses a second frequency different from the first frequency to communicate with the second repeater. Wireless communication between
The second repeater performs wireless communication with the j radio devices using the first frequency, and performs wireless communication with the first repeater using the second frequency. The wireless network system according to claim 3, which is performed. A third repeater for relaying the packet by wireless communication between the first repeater and the second repeater;
The wireless network system according to claim 3 or 4, wherein the third repeater performs wireless communication with the first and second repeaters in an ad hoc mode. The first repeater transmits the first relay packet by unicast,
The wireless network system according to claim 3, wherein the second repeater transmits the second relay packet by unicast. The first repeater transmits the first relay packet by broadcast,
The wireless network system according to claim 3, wherein the second repeater transmits the second relay packet by broadcast. I (i is a positive integer) wireless devices transmitting and receiving packets via the first repeater j (j is a positive integer) wireless devices transmitting and receiving packets via the second repeater A program for causing a computer to execute processing in the first repeater when transmitting the packet to
A first step of receiving m (m is an integer of 2 or more) packets from the i wireless devices;
A second step in which packet generating means generates a relay packet by bundling the m packets received by the receiving means in the first step into one packet;
A program for causing a computer to execute a third step of transmitting a relay packet generated by the packet generation unit in the second step to the second relay.

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