JP4642609B2 - Wireless packet communication system and communication method - Google Patents

Description

  The present invention relates to a wireless communication system in which a terminal can use a plurality of channels or transmission methods in wireless communication, and in particular, the throughput of the entire system is improved by assigning a channel or transmission method suitable for each terminal. The present invention relates to a radio packet communication system and a communication method that are suitable for use in communication.

  Recently, with the spread of wireless local area networks (LANs) and the like, wireless networks in offices are progressing. In addition, services that provide a high-speed wireless communication environment, such as a so-called Hotspot (registered trademark) service, are beginning to spread in cafes and station premises. In a wireless communication system such as a wireless LAN, a method of sharing one channel in time between terminals, such as TDMA (Time Division Multiple Access) and CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance), is common. Is.

  However, when access concentrates on one channel, the throughput of each terminal decreases, and satisfactory services cannot be provided. As a means to prevent this, in locations where access is concentrated, the number of channels is increased by increasing the number of radio base stations, etc., and load distribution between each channel is avoided to avoid a decrease in throughput of each terminal. .

  As a method of performing load distribution between radio base stations, there are methods such as Patent Document 1 and Patent Document 2. Patent Document 1 describes a method in which a base station informs a terminal of the number of associations with the terminal of each base station, and the terminal connects to a base station having a sufficient number of associations and strong signal strength. Patent Document 2 describes a method in which a base station transmits to a terminal the number of terminals connected to each base station, and the terminal connects to a base station with the smallest number of connections.

Non-patent documents 1 and 2 describe other techniques (details will be described later) according to the present invention.
Japanese Patent Laid-Open No. 2005-12724 Japanese Patent Application Laid-Open No. 2005-20565 Toru Sakata, Masataka Iizuka, Hayato Mizoguchi, Masahiro Morikura, “Development of IEEE 802.11a compliant high-speed wireless LAN chipset”, “NTT R & D”, NTT Periodicals / published by the Telecommunications Association, July 2002 No., Vol. 51 No. 7, p. 588-595 Soshi Soda et al., “A New Frequency-domain Link Adaptation Scheme for Broadband OFDM Systems”, Vehicular Technology conferences '99 -Fall, Vol.1, pp.253-257, 1999 (Technical Report of IEICE Technical Report RCS99-171)

  The problems of the methods described in Patent Document 1 and Patent Document 2 are listed below. The problem of the method described in Patent Literature 1 is that a base station to be connected is selected based on the number of associations of each base station, but there is a possibility that there is a terminal that has already been associated and is not communicating, and an efficient load It cannot be said to be distributed. The problem of the method described in Patent Document 2 is that the channel state with the connected base station is not taken into consideration, and there is a possibility that the throughput is reduced by retransmission control or the like. Also, the terminal connected to the base station is not necessarily communicating. Neither of the methods considers the throughput considering the channel state and the number of communicating terminals, and cannot be said to be an efficient load distribution.

  The present invention has been made in view of the above circumstances, and provides a radio packet communication system and communication method capable of improving the efficiency of load distribution in radio communication and improving the throughput of the entire radio communication system. The purpose is to provide.

Further, the present invention provides a wireless packet communication system for transmitting a packet between a plurality of base stations and a terminal via any one of a plurality of channels, while communicating the terminal identification information of the source or destination terminal of the captured packet. Each terminal having a terminal management table for storing each packet along with the transmission rate of the packet as terminal identification information of the terminal, and a plurality of timers for repeatedly measuring a predetermined period, the terminal identification information being stored in the terminal management table A communication state detecting means for allocating one of the plurality of timers to detect the communication state of each channel for each predetermined period, and newly depending on the communication state of each channel detected by the communication state detecting means Channel selection means for selecting a channel for starting communication, and the communication status detection means is stored in the terminal management table. For a terminal in which terminal identification information is stored, if the packet originating or arriving at the terminal is captured before the assigned timer expires, the timer is reset. Regarding the terminal, it is determined that the communication has ended, the terminal identification information is deleted from the terminal management table and the timer assignment is canceled, and the channel selection means is a terminal for each channel stored in the terminal management table. The number of identification information and the transmission rate corresponding to the terminal identification information are acquired, and the throughput of each channel is calculated based on the acquired number of terminal identification information for each channel and the transmission rate corresponding to the terminal identification information and, using the calculated result of the throughput when the terminal performing the new communication request is assumed to use, the plurality of groups Estimating all of the throughput of each channel of the two or more that are used to transmit packets between the station the terminal, a channel to be greatest throughput of the estimation result, wherein said was newly communication request terminal The channel is selected as a channel to be used.

Further, the present invention is characterized in that the communication state detecting means identifies each communication based on at least one of a source address and a destination address included in a packet transmitted / received between a base station and a terminal.

Further, according to the present invention, some or all of the components of the communication state detection unit are distributed or concentrated on either a base station or a load distribution apparatus provided in common to a plurality of base stations. A part or all of each component of the channel selection means is distributed or concentrated in either a base station, a terminal, or a load distribution apparatus provided in common to a plurality of base stations. It is characterized by being provided.
Further, the present invention is characterized in that the plurality of channels include two or more transmission methods.

Further, the present invention provides a wireless packet communication method for transmitting a packet between a plurality of base stations and a terminal via any one of a plurality of channels, while communicating the terminal identification information of the source or destination terminal of the captured packet. The terminal management information is stored in the terminal management table for each channel together with the transmission rate of the packet as terminal identification information of the terminal, and a timer that repeatedly measures a predetermined period is assigned to each terminal for which the terminal identification information is stored in the terminal management table. A communication state detection process for detecting the communication state of each channel for each period, and a channel selection process for selecting a channel for newly starting communication according to the communication state of each channel detected in the communication state detection process. And in the communication state detection process, a terminal for which terminal identification information is stored in the terminal management table is allocated. If the packet originating or arriving at the terminal is captured before the expiration of the timer, the timer is reset. If the packet is not captured, the terminal determines that the communication is terminated and The terminal identification information is deleted from the terminal management table and the timer assignment is canceled. In the channel selection process, the number of terminal identification information for each channel stored in the terminal management table and the terminal identification information are supported. And calculating the throughput of each channel based on the acquired number of terminal identification information for each channel and the transmission speed corresponding to the terminal identification information , using the calculation result of the throughput, Used for packet transmission between the plurality of base stations and the terminal, assuming that the terminal newly making a communication request uses. Is 2 or more for all of the estimates the throughput of each channel, the channel comprising the largest throughput of the estimation result, the terminal performing the new communication request and selecting as the channel for use.

  According to the present invention, since a channel having a small number of communication (the number of terminals or the number of sessions in communication) can be allocated to a terminal that starts a new communication, the throughput of the entire wireless communication system can be improved. Can do. In addition, the throughput considering the transmission speed and the number of terminals in communication can be calculated, and a channel that is estimated to have a high throughput when a terminal starts a new communication can be allocated. be able to.

  Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1]
FIG. 1 shows a configuration diagram of a wireless communication system assumed in the embodiment of the present invention. The wireless communication system in FIG. 1 includes terminals 1 to 3 (T1 to T3), wireless base stations 1 to 3 (B1 to B3) on the network 10 side, and a load distribution apparatus 20. In this wireless communication system, a packet is transmitted between a base station and a terminal via one of a plurality of channels. The plurality of channels include a plurality of transmission schemes having different transmission speeds. The radio base stations B1 to B3 are connected to the load balancer 20 and the Internet network 30, respectively. The radio base stations B1 to B3 have respective cover areas 41, 42 and 43 so as to overlap each other. Each of the terminals T1 to T3 is located in a region where the cover areas 41 to 43 of the radio base stations B1 to B3 overlap, and the radio links L1 to L3 are established with any of the radio base stations B1 to B3. It has become. In FIG. 1, solid arrows indicate the flow of application data, and broken arrows indicate the flow of control data and the like.

  FIG. 2 shows the configuration of terminals T1 to T3 of the present embodiment shown in FIG. The terminal T1 (or T2 or T3, hereinafter referred to as the terminal T1) includes an antenna 51, a switch 52, a load balancer communication interface unit 53, and an application data processing unit 54. The switch 51 performs communication by switching to the A side when performing communication start processing and to the B side after starting communication. The load balancer communication interface unit 53 generates a communication request packet when the terminal T1 performs new communication, and transmits the packet to the load balancer 20 through the radio link L1 and the radio base station B1. The load balancer communication interface unit 53 performs a process of receiving a channel number transmission packet transmitted from the load balancer 20, and performs a process of selecting a channel for communication. The application data processing unit 54 performs a predetermined process on the application data targeted by the application data, and then provides the processed application data.

  FIG. 3 shows the configuration of radio base stations B1 to B3 of the present embodiment. The radio base station B1 (or B2 or B3, hereinafter referred to as a terminal B1) has an antenna 61, a packet discriminator 62, and an Internet connection processing unit 63. The packet discriminator 62 discriminates, from the packet transmitted from the terminal T1, a packet addressed to the load distribution device 20 from the terminal T1 and a packet destined for the Internet network 30, and sends them to the load distribution device 20 or the Internet 30. Process to send. The packet discriminator 62 also transmits a packet addressed to the terminal T1 from the load balancer 20 to the terminal T1. The Internet connection processing unit 63 performs relay processing for communication between the Internet network 30 and the terminal T1.

  FIG. 4 shows the configuration of the load distribution apparatus 20 of the present embodiment. The load distribution apparatus 20 includes a communication monitor 71, a terminal management table 72, a channel management table 73, a channel determiner 74, and a terminal communication interface unit 75.

  The communication monitor 71 monitors the communication state of each channel and grasps the number of terminals in communication (or the number of communication sessions (collectively, the number related to communication)). The communication monitor 71 identifies the terminal in communication by identifying the source address from the terminals T1 to T3 and the destination address to the terminals T1 to T3 in the packet transmitted and received between the network 10 and the terminals T1 to T3. Specifically, it captures packets transmitted and received between the terminals T1 to T3 and the Internet network 30, recognizes an IP (Internet Protocol) address, and determines the number of terminals in communication from the number of different addresses. Recognize For each channel, the terminal numbers of the communicating terminals T1 to T3 are managed together with the addresses in a terminal management table 72 as shown in Table 1. Note that the source address in the packet transmitted from the terminals T1 to T3 and the destination address in the packet transmitted from the base station correspond to the address assigned to the terminal. Therefore, it is possible to identify a terminal in communication by identifying at least one of a source address and a destination address included in a packet transmitted and received between the base station and the terminal.

  In the terminal management table 72 of Table 1, terminal numbers (“001”, “002”,...) Set for each channel number in correspondence with channel numbers (“1”, “2”,...), An IP address (such as “10.182.12.1”) corresponding to each terminal is registered.

  The communication monitor 71 also has a communication identification timer 711 including a plurality of timers that repeatedly measure a predetermined time. The communication monitor 71 performs a process of assigning any one of a plurality of timers forming the communication identification timer 711 for each of the terminals T1 to T3 in order to recognize whether or not the terminals T1 to T3 are communicating. . Then, when the packet transmitted from the terminal by the expiration of the timer or the packet addressed to the terminal is recognized, the timer is reset, and the packet transmitted / received by the terminal has not been transmitted / received by the expiration of the timer. Regarding the terminal, it is determined that the communication has ended, and is deleted from the terminal management table 72. Since one of the plurality of timers constituting the communication identification timer 711 is assigned to each IP address (each communication or each terminal) in this way, the elapsed time of communication can be measured at each timing for each IP address. In addition, by sharing the setting value of each timer of the communication identification timer 711 with each terminal T1 to T3 in advance, it is possible to prevent the communication from being disconnected at an unintended timing.

  In addition, the communication monitor 71 calculates the number of terminals that are communicating on each channel from the terminal management table 72 and writes the channel number into the channel management table 73 as shown in Table 2.

  In the channel management table 73 of Table 2, the number of terminals in communication (“3” units, “2” units,...) Is registered in association with channel numbers (“1”, “2”,...). Yes.

  Flow charts of the communication monitor 71 are shown in FIGS. 5, 6, and 7. FIG. 5 is a flowchart showing the flow of processing by the communication monitor 71, FIG. 6 is a flowchart of packet analysis processing in step S102 of FIG. 5, and FIG. 7 is step S107 in FIG. 5 and step S207 in FIG. It is a flowchart of a channel management table update process. As shown in FIG. 5, the communication monitor 71 first determines whether or not a packet flowing between the network 10 and the terminals T1 to T3 is detected (step S101), and if a packet is detected, the packet is detected. After performing the analysis process (step S102), it is determined whether there is a terminal registered in the terminal management table 72 (step S103).

  In the packet analysis processing in step S102, as shown in FIG. 6, the detected packet is captured (step S201), and its IP address is acquired (step S202). Next, it is determined whether or not the acquired IP address is registered in the terminal management table 72 (step S203). If the acquired IP address is a registered IP address, the communication identification set corresponding to the IP address is determined. One of the timers 711 is reset (step S204). On the other hand, if it is determined in step S203 that it is not registered, a new communication terminal number is added and registered in the terminal management table 72 together with the IP address (step S205). Next, a timer for the terminal is created (that is, assigned) in the communication identification timer 711, and an initial value is set in the timer (step S206). Then, the channel management table 73 is updated (step S207). In the channel management table update process of step S207, as shown in FIG. 7, the number of terminals communicating in each channel is acquired from the terminal management table 72 (step S301) and written to the channel management table 73 (step S302). .

  On the other hand, when it is determined in step S103 of FIG. 5 that there is a terminal registered in the terminal management table 72, the timer value of each terminal of the communication identification timer 711 is set to a predetermined amount (for example, “1”). The number is decreased (step S104), and if it is determined that there is no terminal, the process returns to step S101. When the timer of each terminal is decreased in step S104, it is determined whether there is any timer that has expired (eg, “0”) (step S105). When there is an expired item (“yes” in step S105), the terminal registration information and the terminal timer of the communication identification timer 711 are deleted (deallocated) from the terminal management table 72 (step S106). ), The channel management table 73 shown in FIG. 7 is updated (step S107). On the other hand, when there is no expired item and when the processes of steps S106 and S107 are performed, the process returns to step S101.

  Further, the channel determiner 74 in FIG. 4 selects the channel with the least number of terminals in communication with reference to the channel management table 73 according to the activation trigger sent from the terminal communication interface unit 75, and selects the selected channel. Send back the number. The terminal communication interface unit 75 receives a communication request packet transmitted from the terminals T1 to T3, and generates a channel number transmission packet to transmit the channel number selected by the channel determiner 74. Transmit to terminals T1 to T3 through stations B1 to B3 and radio links L1 to L3.

  FIG. 8 shows a flowchart of the radio communication system of the present embodiment whose configuration is shown in FIGS. 1 and 2 to 4. Hereinafter, a communication start process example of the new terminal will be described with reference to FIG. The number of radio base stations is 3, each has one radio channel, and each channel number is 1 to 3. It is assumed that three, two, and three terminals are communicating with each channel, and the terminal management table 72 and channel management table 72 in the load balancer 20 are as shown in Tables 1 and 2. Registration has been made.

  First, a terminal (for example, T1) that starts new communication sets the switch 52 to the A side, and makes a communication request to the load balancer 20 via the load balancer communication interface unit 53 (step S401). The load balancer 20 receives a communication request in the terminal communication interface unit 75 and activates the channel determiner 74 (step S402). The channel determiner 74 refers to the channel management table 73 (Table 2) and selects channel number 2 with the least number of terminals in communication (steps S403 to S404). The selected channel number is transmitted to the terminal (T1) via the terminal communication interface unit 75 (step S405). Here, the terminal management table 72 and the channel management table 73 are updated (step S406).

  The terminal (T1) receives the channel number designated in the load balancer communication interface unit 53 (step S407), and starts communication using this channel (step S408). The terminal (T1) switches the switch 52 to the B side and connects to the Internet network 30. When the terminal (T1) does not transmit / receive a packet before the timer assigned to the terminal in the communication identification timer 711 expires, the communication start process is performed again from the beginning.

  As described above, according to the present embodiment, the communication state of each channel is detected every predetermined period, and a channel for newly starting communication is selected according to the detected communication state of each channel. ing. Therefore, efficient load distribution can be performed according to the terminal that is actually communicating.

[Embodiment 2]
Next, another embodiment of the present invention will be described with reference to FIGS. The configuration of the wireless communication system in the present embodiment is the same as that in FIG. However, in the present embodiment, different reference numerals are used for the components corresponding to the terminals 1 to 3 (T1 to T3), the radio base stations 1 to 3 (B1 to B3), and the load distribution apparatus 20 in FIG. Yes. That is, terminal T1 (to T3) is shown as terminal T1a (to T3a), radio base stations B1 to B3 are shown as radio base stations B1a to B3a, and load distribution apparatus 20 is shown as load distribution apparatus 20a.

  Further, in each drawing, the same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the corresponding components are denoted by a reference numeral added with an alphabetic character “a” at the end.

  FIG. 9 shows a configuration example of the terminal T1a of the present embodiment. The terminal T1a includes an antenna 51, a switch 52, a load balancer communication interface unit 53, a channel determination unit 55, and an application data processing unit 54. The channel determiner 55 is a configuration newly provided in the present embodiment, and during communication of each channel obtained by receiving a beacon transmitted from the load balancer 20a via each base station B1a to B3a The channel with the least number of terminals in communication is selected from the number of terminals. The load balancer communication interface unit 53 performs a process of acquiring the number of terminals that are communicating on each channel from the beacon transmitted from the load balancer 20a. With the above configuration, in the present embodiment, when a channel is selected, information indicating the communication state of each channel is periodically broadcast from the base station to all terminals, and this is received by the terminal and received. A channel for newly starting communication is selected by performing predetermined processing based on the information.

  On the other hand, the network 10 side includes radio base stations B1a to B3a and a load balancer 20a. FIG. 10 shows the configuration of the radio base station B1a of the present embodiment. The radio base station B1a includes an antenna 61, a beacon transmitter 64, and an Internet connection processing unit 63. The beacon transmitter 64 is a configuration newly provided in the present embodiment, stores information on the number of communicating terminals of each channel sent from the load balancer 20a in the beacon, and periodically transmits the terminals T1a to T1a. Informs T3a.

  FIG. 11 shows the configuration of the load distribution apparatus 20a of the present embodiment. The load balancer 20a includes a communication monitor 71, a terminal management table 72, a channel management table 73, and a terminal communication interface unit 75a. The operation of the communication monitor 71 is the same as that of the first embodiment. The terminal communication interface unit 75a reads the number of terminals that are communicating on each channel from the channel management table 73 and sends the number to the radio base station B1a and the like.

  A flowchart of wireless communication according to this embodiment is shown in FIG. The communication start process of the new terminal is shown below. The number of radio base stations is 3, and the respective channel numbers are 1 to 3. Assume that two, three, and one terminal are communicating with each channel. The terminal management table 72 and the channel management table 73 in the load distribution apparatus 20a are registered as shown in Tables 3 and 4.

  First, the load distribution apparatus 20a reads out the number of terminals communicating in each channel from the channel management table 73 in the terminal communication interface unit 75a, and transmits the number to the radio base stations B1a to B3a (step S501). The radio base stations B1a to B3a notify the terminal T1a (to T3a) of information on the number of terminals that are communicating on each channel using beacons (step S502).

  The terminal T1a receives the beacon and grasps the number of terminals that are communicating on each channel (step S503). In this example, the channel determiner 55 selects channel number 3 with the least number of terminals in communication, and starts communication using this channel (step S504).

[Embodiment 3]
Next, another embodiment of the present invention will be described with reference to FIGS. The configuration of the wireless communication system in the present embodiment is the same as that in FIG. However, in this embodiment, different reference numerals are used for the respective components corresponding to the radio base stations 1 to 3 (B1 to B3) and the load distribution apparatus 20 in FIG. That is, the radio base stations B1 to B3 are shown as radio base stations B1b to B3b, and the load balancer 20 is shown as a load balancer 20b. Moreover, in each figure, the same reference numerals are given to the same components as those shown in FIGS. 1 to 4 and 9 to 11, and the corresponding symbols are suffixed with the letter “b” at the end. Is attached.

  The configurations of the terminals T1 to T3 are the same as those in FIG. 2 (Embodiment 1). However, the load balancer communication interface 53 (see FIG. 2) has a function of transmitting a reference signal to the radio base stations B1b to B3b in addition to transmission / reception of packets with the load balancer 20b.

  The configuration of the radio base station B1b on the network 10 side is shown in FIG. The radio base station B1b includes an antenna 61, a reception intensity observer 65, a packet discriminator 66, and an Internet connection processing unit 63. The reception intensity observer 65 receives the reference signal transmitted from the terminals T1 to T3 and observes the reception intensity. The packet discriminator 62 discriminates, from the packet transmitted from the terminal T1, a packet addressed to the load distribution device 20 from the terminal T1 and a packet destined for the Internet network 30, and sends them to the load distribution device 20 or the Internet 30. Process to send.

  FIG. 14 shows the configuration of the load distribution apparatus 20b of the present embodiment. The load balancer 20b includes a communication monitor 71, a transmission rate reader 76, a reception intensity / transmission rate correspondence table 77, a terminal management table 72b, a channel management table 73b, a throughput calculator 78, a channel determiner 74, and a terminal communication interface unit. 75.

  The communication monitor 71 is the same as that shown in the first embodiment. The transmission rate reader 76 reads out the transmission rate corresponding to the observed reception strength from the reception strength / transmission rate correspondence table 77 shown in Table 5, and sends the reference signal to the terminal management table 72b by referring to the address. recognize.

  As shown in Table 5, the reception strength / transmission rate correspondence table 77 shows a correspondence relationship between the reception strength and the transmission rate as a list, and the correspondence relationship between the reception strength and the transmission rate is calculated or measured. Is set based on. As shown in Table 6, the terminal management table 72b has a transmission rate element added to the terminal management table 72 of the first embodiment. As shown in Table 7, the channel management table 73b has a throughput factor for each channel added to the channel management table 73 of the first embodiment.

  The throughput calculator 78 reads the number of terminals communicating in each channel from the channel management table 73 b and the transmission rate of the communicating terminal from the terminal management table 72 b, and transmits this information and the transmission rate reader 76. The throughput in each channel is calculated from the transmission rate information in each channel of the new communication start terminal.

  A formula for deriving the throughput Tk (m) of the terminal of the terminal number m in the channel number k is shown in Expression (1).

  Tk (m) = Rk (m) / Nk (1)

  Here, Rk (m) is the transmission rate of the terminal at channel number k, and Nk is the number of terminals in communication at channel number k. When terminal numbers 1 to n are assigned to n terminals communicating in channel number k, the total throughput STk of all terminals in channel number k can be written by equation (2).

  STk = Tk (1) + Tk (2) +... + Tk (n) (2)

  The calculated total throughput value of all terminals is stored in the channel management table 73b shown in Table 7 together with the number of communicating terminals for each channel.

  The throughput calculator 78 calculates the expected throughput in each channel when one terminal for starting new communication is added as follows. An expression for deriving the expected throughput T′k (m) of the terminal number m in the channel number k is shown in Expression (3).

  T′k (m) = Rk (m) / ((Nk) +1) (3)

  Further, assuming that T′k (new) is the expected throughput of the new communication start terminal in channel number k, the total expected throughput ST′k of all terminals in channel number k can be written by equation (4).

  ST′k = T′k (1) + T′k (2) +... + T′k (n) + T′k (new) (4)

  The channel determiner 74 calculates the difference between STk and ST′k of all channels, and when assigning a new communication terminal to the channel, when ST′k increases or all ST′k decreases Determines the channel with the smallest decrease. Thereafter, the terminal management table 72b and the channel management table 73b are updated.

  The terminal communication interface unit 75 receives a communication request packet transmitted from the terminal. In addition, channel number transmission packets are transmitted to the terminals T1 to T3 through the radio base stations B1b to B3b and the radio links L1 to L3.

  15, 16, and 17 are flowcharts showing the process flow of the entire system in this embodiment. Hereinafter, the communication start process of the new terminal will be described with reference to these flowcharts. The number of radio base stations is 3, and the respective channel numbers are 1 to 3. Based on IEEE (Institute of Electrical and Electronic Engineers) 802.11a, the transmission speed of the channel is selected from 6 Mbit / s, 12 Mbit / s, and 24 Mbit / s according to the channel status. Assume that two, two, and three terminals are communicating with each channel, and are registered in the terminal management table 72b in the load balancer 20b as shown in Table 6.

The total throughput of each channel is
ST1 = 6/2 + 12/2 = 3 + 6 = 9 [Mbit / s],
ST2 = 12/2 + 12/2 = 6 + 6 = 12 [Mbit / s],
ST3 = 6/3 + 12/3 + 24/3 = 2 + 4 + 8 = 14 [Mbit / s]
(The calculation method is described in paragraph 0073), and is stored in the channel management table 73b in the load balancer 20b as shown in Table 7.

    First, a terminal (here, terminal T1) makes a communication request (step S601 in FIG. 15). Next, the reference signal is transmitted to all the radio base stations B1b to B3b (step S602 in FIG. 15). The radio base stations B1b to B3b observe the reception intensity of the reference signal received by the reception intensity observer 65. The packet discriminator 66 analyzes the IP address and recognizes a new communication terminal. The observed received intensity is transmitted to the load balancer 20b together with the IP address, and the load balancer 20b acquires them (step S701 in FIG. 16).

  Next, in the load balancer 20b, the transmission rate reader 76 derives the transmission rate from the received reception intensity (step S702). For example, it is assumed that the reception strength of channel number 1 is -93 dBm, the reception strength of channel number 2 is -82 dBm, and the reception strength of channel number 3 is -88 dBm. In this case, from the reception intensity / transmission rate correspondence table 77 (Table 5), the respective transmission rates are 6 Mbit / s, 24 Mbit / s, and 12 Mbit / s. Information on these transmission rates is transmitted to the throughput calculator 78.

  Next, the throughput calculator 78 acquires the number of terminals that are communicating on each channel from the channel management table 73b, and acquires the transmission rate of each terminal from the terminal management table 72b (step S703). Next, the throughput of the currently communicating terminal is calculated from the number of communicating terminals of each channel and the transmission rate of each terminal (step S704). Then, the current total throughput is calculated (step S705). However, these values can be calculated in advance, and can be calculated at different timings and stored in the channel management table 73b.

  Next, the throughput calculator 78 calculates the expected throughput T1 (new), T2 (new), and T3 (new) of the new communication terminal in each channel based on the above information (step S706).

T1 (new) = 6/3 = 2 [Mbit / s],
T2 (new) = 24/3 = 8 [Mbit / s],
T3 (new) = 12/4 = 3 [Mbit / s]

  Next, the transmission rate of each terminal is acquired from the channel management table 73b, the expected throughput of the communicating terminal in each channel is calculated, and the total expected throughput is calculated (step S707).

ST′1 = 6/3 + 12/3 + 2 = 8 [Mbit / s],
ST ′ 2 = 12/3 + 12/3 + 8 = 16 [Mbit / s],
ST'3 = 6/4 + 12/4 + 24/4 + 3 = 13.5 [Mbit / s]

  After the calculation, ST1, ST2, and ST3 stored in the channel management table are read and transmitted to the channel determiner 74. Channel determiner 74 compares ST1, ST2, ST3 with ST'1, ST'2, ST'3.

  In this case, since the expected throughput increases when the new communication terminal is assigned to channel number 2, channel number 2 is determined as the channel of the new communication terminal (step S708). Channel number 2 is transmitted to the new communication terminal (T1) via the terminal communication interface 75 (step S709), and then the terminal management table 72b and the channel management table 73b are updated (step S710).

  The terminal (T1) receives the channel number (step S801 in FIG. 17), and starts communication with the channel number 2 (step S802).

  As described above, the present embodiment detects the number of terminals communicating with each channel (the number related to communication) and the transmission speed of each communication as the communication state of each channel, and the number of terminals communicating with each channel. And the transmission rate of each communication, the throughput of each channel is calculated, and a channel for newly starting communication is selected based on the calculation result. Further, in the present embodiment, when selecting a channel for newly starting communication based on the calculation result of the throughput, the throughput calculation result is obtained by calculating the throughput of two or more channels when it is assumed that communication is newly started. It is estimated (predicted) using the channel, and a channel is selected based on the estimation result.

[Embodiment 4]
Next, another embodiment of the present invention will be described with reference to FIGS. The configuration of the wireless communication system in the present embodiment is the same as that in FIG. However, in this embodiment, different reference numerals are used for the components corresponding to the terminals 1 to 3 (T1 to T3) and the load distribution apparatus 20 in FIG. That is, the terminal T1 (to T3) is shown as a radio base station T1c (to T3c), and the load balancer 20 is shown as a load balancer 20c. Also, in each figure, the same components as those shown in FIGS. 1 to 4, 9 to 11 and 13 to 14 are given the same reference numerals, and the corresponding components are suffixed with the letter “c”. "Is added to the reference symbol.

  FIG. 18 is a diagram illustrating the configuration of the base stations B1 to B3. This figure is almost the same as FIG. 3 (Embodiment 1), but the base stations B1 to B3 each further have a beacon transmitter 64 (Embodiment 2) described with reference to FIG. To do.

  FIG. 19 shows the configuration of the terminal T1c of this embodiment. The terminal T1c includes an antenna 51, a switch 52c, a reception intensity observer 56, a transmission rate reader 57, a reception intensity / transmission rate correspondence table 58, a load balancer communication interface unit 59, and an application data processing unit 54. The reception intensity observer 56 receives the beacons emitted from the base stations B1 to B3 and observes the reception intensity. The transmission rate reader 57 corresponds to the observed reception strength from the reception strength / transmission rate correspondence table 58 configured in the same manner as the reception strength / transmission rate correspondence table 77 described with reference to Table 5 and FIG. Read the transmission rate. The load balancer communication interface unit 59 transmits the communication request packet including the read transmission rate information to the load balancer 20c through the radio links L1 to L3 and the radio base stations B1 to B3. Also, a process of receiving a channel number transmission packet transmitted from the load balancer 20c is performed.

  On the other hand, the network 10 side includes radio base stations B1 to B3 and a load balancer 20c. FIG. 20 shows the configuration of the load distribution apparatus 20c of this embodiment. The load balancer 20c includes a communication monitor 71, a terminal management table 72b, a channel management table 73b, a throughput calculator 78, a channel determiner 74, and a terminal communication interface unit 75. The communication monitor 71 is the same as that shown in the first embodiment. The throughput calculator 78 and the channel determiner 74 are the same as those shown in the third embodiment. The terminal communication interface unit 75 receives a communication request packet transmitted from the terminal T1c. Further, a channel number transmission packet is transmitted to the terminal through the radio links L1 to L3 and the radio base stations B1 to B3.

  21, 22 and 23 are flowcharts showing the process flow of the entire system in this embodiment. The communication start process of the new terminal is shown below. The number of radio base stations is 3, and the respective channel numbers are 1 to 3. Based on IEEE802.11a, the transmission rate of the channel is selected from 6 Mbit / s, 12 Mbit / s, and 24 Mbit / s depending on the channel status. It is assumed that two, two, and three terminals are communicating with each channel, and are registered in the terminal management table 72b in the load balancer 20c as shown in Table 8.

The total throughput of each channel is
ST1 = 6/2 + 6/2 = 3 + 3 = 6 [Mbit / s],
ST2 = 12/2 + 6/2 = 6 + 3 = 9 [Mbit / s],
ST3 = 12/3 + 12/3 + 24/3 = 4 + 4 + 8 = 16 [Mbit / s]
(The calculation method is described in paragraph 0092), and is stored in the channel management table 73b in the load balancer 20c as shown in Table 9.

  First, the terminal T1c connects to all channels, performs beacon reception, and observes the reception strength of each channel from the received beacon (step S901 in FIG. 21). Assuming that the reception strength of channel number 1 is -93 dBm, the reception strength of channel number 2 is -82 dBm, and the reception strength of channel number 3 is -84 dBm, the respective transmission rates from the reception strength / transmission rate correspondence table 58 (see Table 5). Are 6 Mbit / s, 24 Mbit / s, and 24 Mbit / s.

  Next, the information on these transmission rates is transmitted to the load balancer 20c on the network 10 side via the wireless links L1 to L3 together with the communication request (step S903), and they are acquired in the load balancer 20c (FIG. 22 step S1001).

  Next, the throughput calculator 78 acquires the number of terminals that are communicating on each channel from the channel management table 73b, and acquires the transmission rate of each terminal from the terminal management table 72b (step S1002). Next, the throughput of the currently communicating terminal is calculated from the number of communicating terminals on each channel and the transmission rate of each terminal (step S1003). Then, the current total throughput is calculated (step S1004). However, these values can be calculated in advance, and can be calculated at different timings and stored in the channel management table 73b.

  Based on these pieces of information, the load distribution apparatus 20c calculates expected throughputs T1 (new), T2 (new), and T3 (new) of new communication terminals in each channel (step S1005).

T1 (new) = 6/3 = 2 [Mbit / s],
T2 (new) = 24/3 = 8 [Mbit / s],
T3 (new) = 24/4 = 6 [Mbit / s]

  Next, the expected throughput of the terminal in communication is calculated, and the total expected throughput is calculated (step S1006).

ST′1 = 6/3 + 6/3 + 2 = 6 [Mbit / s],
ST ′ 2 = 12/3 + 6/3 + 8 = 14 [Mbit / s],
ST'3 = 12/4 + 12/4 + 24/4 + 6 = 18 [Mbit / s]

  Therefore, in this example, since the expected throughput of the new communication terminal assigned to channel number 2 increases, channel number 2 is transmitted to terminal T1c (steps S1007 to S1008). Thereafter, the load distribution apparatus 20c updates the terminal management table 72b and the channel management table 73b (step S1009).

  The terminal T1c receives the channel number (step S1101 in FIG. 23), and starts communication with the channel number 2 (step S1102).

[Embodiment 5]
Next, another embodiment of the present invention will be described with reference to FIGS. The configuration of the wireless communication system in the present embodiment is the same as that in FIG. However, different reference numerals are used for the components corresponding to the terminals 1 to 3 (T1 to T3) in FIG. 1 in the present embodiment. That is, the terminal T1 (to T3) is shown as the radio base station T1d (to T3d). Moreover, in each figure, the same structure as what was shown in FIGS. 1-4, 9-11, 13-14, and 18-20 is attached with the same referential mark, and it becomes a corresponding structure. Is given a reference sign with an English letter “d” added to the end.

  The network 10 side includes radio base stations B1a to B3a and a load balancer 20a. The configurations of the radio base stations B1a to B3a are the same as those in FIG. 10 (Embodiment 2). The configuration of the load balancer 20a is the same as that in FIG. 11 (Embodiment 2).

  FIG. 24 shows a terminal T1d of this embodiment. The terminal T1d includes an antenna 51, a switch 52d, a reception intensity observer 56, a transmission rate reader 57, a reception intensity / transmission rate correspondence table 58, a throughput calculator 81, a channel determiner 82, a load balancer communication interface unit 59d, an application The data processing unit 54 is configured. The operations of the reception intensity observer 56 and the transmission rate reader 57 are the same as those shown in FIG. 19 (Embodiment 4).

  The operation of the load balancer communication interface unit 59d is the same as that of the load balancer communication interface unit 59 described in the second embodiment. Throughput calculator 81 calculates the expected throughput in each channel when the own terminal is added, from the number of communicating terminals of each channel obtained by receiving the beacon and the transmission rate derived from the received intensity. . The derivation of the expected throughput follows equation (3). However, only the expected throughput of the terminal itself is calculated.

  From the calculated throughput of each channel, the channel determiner 82 selects a channel in which the expected throughput of the own terminal increases when the own terminal starts communication and the number of other communicating terminals is small.

  25 and 26 are flowcharts showing the process flow of the entire system in this embodiment. The communication start process of the new terminal is shown below. The number of radio base stations is 3, and the respective channel numbers are 1 to 3. Based on IEEE802.11a, the channel transmission rate is selected from 6 Mbit / s, 12 Mbit / s, and 24 Mbit / s depending on the channel status. It is assumed that two, three, and one terminal are communicating with each channel, and the terminal management table 72 and the channel management table 73 in the load balancer 20a (FIG. 11) are shown in Tables 10 and 11 respectively. It is registered as shown in

  First, in the terminal communication interface unit 75a, the load distribution apparatus 20a reads out the number of terminals that are communicating on each channel from the channel management table 72 (step S1201 in FIG. 25), and transmits it to the radio base stations B1a to B3a. The radio base stations B1a to B3a notify the information to the terminal T1d using a beacon (step S1202).

  The terminal T1d receives the beacon and grasps the number of terminals in communication on each channel (step S1301 in FIG. 26). Furthermore, the terminal T1d performs beacon reception for all channels and observes the respective reception strengths (step S1302). Assuming that the reception strength of channel number 1 is -91 dBm, the reception strength of channel number 2 is -84 dBm, and the reception strength of channel number 3 is -88 dBm, each transmission rate is 6 Mbit from the reception strength / transmission rate correspondence table 58 of Table 5. / S, 24 Mbit / s, and 12 Mbit / s (step S1303). Next, expected throughputs T1 (new), T2 (new), and T3 (new) of the own terminal in each channel are calculated (step S1304).

T1 (new) = 6/3 = 2 [Mbit / s],
T2 (new) = 24/4 = 6 [Mbit / s],
T3 (new) = 12/2 = 6 [Mbit / s]

  Therefore, in this case, the expected throughput of channel 2 and channel 3 is increased. Among these, since the channel with a small number of other terminals in communication is channel number 3, communication is started with channel number 3 (step S1305).

  As described above, according to each embodiment of the present invention, a channel with few terminals that are actually communicating can be allocated to a terminal that starts a new communication, thereby improving the throughput of the entire wireless communication system. be able to.

  Further, the throughput considering the channel state and the number of terminals in communication can be calculated, and a channel whose expected throughput becomes high when the terminal starts new communication can be allocated, so that the throughput of the entire wireless communication system can be improved. it can.

  In addition, since the load balancer broadcasts the number of terminals in communication on each channel using a beacon, the channel used can be determined by the terminal, so there is no need to transmit information from the terminal to the load balancer. The amount of communication between the load balancer and the terminal in the section can be reduced. This is because there are many terminals that start new communication and communication start / load distribution processing frequently occurs, or the channel transmission rate changes in the terminal and channel reassignment / load distribution processing is frequently performed. In this case, the time occupation in the radio link due to the processing can be reduced.

  Further, the present invention is a wireless communication system in which a terminal can use a plurality of channels. A terminal that is communicating is identified, and a terminal that starts a new communication communicates using a channel with the least number of terminals that are communicating. As the number of terminals decreases, the time that the terminals can occupy the channel increases and the throughput is improved.

  In addition, in order to calculate the throughput considering the channel state and the number of terminals in communication and perform load distribution efficiently between multiple channels, the state of each channel (transmission speed, etc.) before the terminal starts communication. Then, the number of terminals in communication in each channel is grasped, and the throughput is calculated from these pieces of information. In general, the higher the reception strength, the better the channel state, the higher the transmission rate, and the higher the throughput. For example, Non-Patent Document 1 describes UDP (User Datagram Protocol) throughput according to the received power level. Non-Patent Document 2 describes an average transmission rate with respect to carrier-to-noise power. This indicates that the transmission rate increases as the channel state improves. Further, as described above, the smaller the number of terminals, the longer the time for which the terminals can occupy the channel and the higher the throughput. Therefore, when the terminal starts communication, the expected throughput is calculated from the channel state and the number of communicating terminals, and the terminal connects to the channel with the highest throughput to start communication, thereby performing optimum load distribution. Will be able to.

  Note that the embodiment of the present invention is not limited to the above, and it is possible to integrate or divide each configuration, and to provide some configurations redundantly. For example, a load balancer and a part of base stations can be integrated, a part of tables can be distributed to terminals, a load balancer and base stations, or each table can be integrated as one database. It is possible to provide each table, or to provide each table in duplicate in each configuration. That is, in the present invention, some or all of the constituent elements of the means for detecting the communication state and the means for selecting the channel are provided in common for the base station, terminal, or a plurality of base stations. It is possible to disperse or concentrate the load on any of the load distribution devices.

  Correspondence between the configuration of each embodiment and the configuration described in the claims is as follows. “Communication state detection means for detecting the communication state of each channel every predetermined period” corresponds to the communication monitor 71 shown in FIG. Here, the communication state of each channel includes the number of terminals communicating with each channel, reception strength, transmission speed, throughput, and the like. “Channel selection means for selecting a channel for newly starting communication according to the communication state of each channel detected by the communication state detection means” is the channel determination unit 74 shown in FIG. 4 and the like, and the channel determination shown in FIG. 55 corresponds to the channel determiner 82 shown in FIG.

  The configuration in which the communication state detection means detects the number of communication in each channel and the transmission speed of each communication as the communication state of each channel corresponds to the processing in steps S701 to S702 in FIG. In this case, the “communication state detection means” includes not only the communication monitor 71 but also the configuration such as the transmission rate reader 76 of FIG. The “number related to communication” means the number of terminals in communication or the number of communication sessions. “The channel selection means calculates the throughput of each channel based on the number of communication in each channel and the transmission speed of each communication, and selects a channel for newly starting communication based on the calculation result. The configuration corresponds to the processing in step S705 in FIG. 16 and the like, and the “channel selection means” includes the configuration of the throughput calculator 78 in FIG.

  “When the channel selection means selects a channel for newly starting communication based on the calculation result of throughput, the throughput of two or more channels when assuming that communication is newly started is calculated using the calculation result of throughput. The configuration of “estimating and selecting a channel based on the estimation result” corresponds to the processing in step S706 in FIG. 16 and the like. The “channel selection means” includes the channel determiner 74 and FIG. The throughput calculator 78 and the like are included.

  “Channel selection means periodically notifies information indicating the communication status of each channel from the base station to all terminals, and selects a channel for newly starting communication based on the information received at the terminal. The means "corresponds to the beacon transmitter 64 in FIG. 10, the channel determiner 55 in FIG.

  “The communication state detection means identifies each communication based on at least one of the source address and the destination address included in the packet transmitted and received between the base station and the terminal” in the processing of steps S201 to S205 in FIG. It corresponds to. “The communication state detecting means has a plurality of timers and assigns each timer to each communication to measure a predetermined period” corresponds to the processing in step S206 in FIG. “A part or all of the components of the communication state detection unit and the channel selection unit are distributed or concentrated in either a base station, a terminal, or a load distribution apparatus provided in common to a plurality of base stations. The “provided” points represent the configurations of the first to fifth embodiments in which the arrangement of each component is different.

  The point that “a plurality of channels include two or more transmission schemes” corresponds to the fact that transmission schemes having different transmission rates can be selected for each channel.

  The features of the present invention can be understood as the following aspects. That is, in the first aspect, in a wireless packet communication system in which a packet is transmitted between a base station and a terminal via one of a plurality of channels, channel selection means for selecting a channel for communication, and Address identifying means for identifying the originating address from the terminal in the packet transmitted and received between the terminals and the destination address to the terminal, timer means for repeatedly measuring a predetermined time, and the originating address identified within the predetermined time in the previous period And / or address counting means for counting the number of called addresses for each channel, wherein the channel selecting means selects a channel having the smallest number of source addresses and / or number of called addresses for each channel. 1 is a wireless packet communication system.

  According to a second aspect, in the wireless packet communication system according to the first aspect, the base station includes channel selection means, a means for transmitting a communication start request from the terminal to the base station, and a channel for the terminal that requested the communication start Means is provided for transmitting the channel selected by the selecting means, and the terminal starts communication using the transmitted channel. According to a third aspect, in the wireless packet communication system according to the first aspect, the terminal includes channel selection means, and further includes means for transmitting the source address and / or the number of destination addresses from the base station to the terminal. It is.

  In a wireless packet communication system that transmits a packet between a base station and a terminal or through a plurality of channels, a fourth mode includes channel selection means for selecting a channel for communication, and a network and a terminal at the base station. Address identifying means for identifying the originating address from the terminal in the packet transmitted and received and the destination address to the terminal, timer means for repeatedly measuring a predetermined time, and the originating address identified within the predetermined time and / or Address counting means for counting the number of called addresses for each channel, transmission speed estimating means for estimating the transmission speed of two or more channels among a plurality of channels, estimated transmission speed and addresses counted by the address counting means Provided with throughput estimation means for estimating the throughput between the base station and the terminal from the number, the channel selection means is A wireless packet communication system, wherein a throughput estimated for each channel to select the most larger channel.

  According to a fifth aspect, in the wireless packet communication system according to the fourth aspect, the base station includes channel selection means, a means for transmitting a communication start request from the terminal to the base station, and a channel for the terminal that has requested the communication start. Means is provided for transmitting the channel selected by the selecting means, and the terminal starts communication using the transmitted channel. According to a sixth aspect, in the wireless packet communication system according to the fifth aspect, the terminal includes transmission rate estimation means and means for transmitting the estimated transmission rate to the base station. A seventh aspect is the radio packet communication system according to the fourth aspect, wherein the terminal includes transmission rate estimation means and channel selection means, and further includes means for transmitting the source address and / or the number of destination addresses from the base station to the terminal. It is characterized by this.

  The eighth aspect is characterized in that the means for transmitting the source address and / or the number of destination addresses from the base station of the third aspect or the seventh aspect periodically notifies all terminals. Is. According to a ninth aspect, in the radio packet communication system according to the third aspect or the seventh aspect, the wireless packet communication system includes means for transmitting a communication start request from the terminal to the base station, and the source address and / or the number of destination addresses are determined from the base station. The means for transmitting to the terminal transmits the source address and / or the number of destination addresses to the terminal that has requested the start of communication.

  The plurality of channels in the first to ninth aspects may include two or more transmission methods.

  The channel selection according to the present embodiment is performed at the start of communication. However, by selecting these channels during communication, the optimal channel selection can be performed even when the communication characteristics change during communication. You may be able to.

1 is a system diagram showing a wireless packet communication system of the present invention. It is a block diagram which shows the structural example of terminal T1-T3 of FIG. It is a block diagram which shows the structural example of base station B1-B3 of FIG. It is a block diagram which shows the structural example of the load distribution apparatus 20 of FIG. It is a flowchart which shows the process of the communication monitor 71 of FIG. It is a flowchart which shows packet analysis process S102 of FIG. It is a flowchart which shows the channel management table update process S107 or S207 of FIG. 5 or FIG. 2 is a flowchart illustrating processing of the wireless packet communication system (first embodiment) in FIG. 1. It is a block diagram which shows the structure of terminal T1a-T3a in Embodiment 2 of this invention. It is a block diagram which shows the structure of base station B1a-B3a in Embodiment 2 of this invention. It is a block diagram which shows the structure of the load distribution apparatus 20a in Embodiment 2 of this invention. It is a flowchart which shows the process of the radio | wireless packet communication system (Embodiment 2) of this invention. It is a block diagram which shows the structure of base station B1b-B3b in Embodiment 3 of this invention. It is a block diagram which shows the structure of the load distribution apparatus 20b in Embodiment 3 of this invention. It is a flowchart which shows the process of the radio | wireless packet communication system (Embodiment 3) of this invention with FIG.16 and FIG.17. 18 is a flowchart showing processing of the wireless packet communication system (Embodiment 3) of the present invention together with FIGS. 15 and 17. 17 is a flowchart showing processing of the wireless packet communication system (Embodiment 3) of the present invention together with FIGS. 15 and 16. It is a figure which shows the structure of base station B1-B3 in Embodiment 4 of this invention. It is a block diagram which shows the structure of terminal T1c-T3c in Embodiment 4 of this invention. It is a block diagram which shows the structure of the load distribution apparatus 20c in Embodiment 4 of this invention. It is a flowchart which shows the process of the radio | wireless packet communication system (Embodiment 4) of this invention with FIG.22 and FIG.23. It is a flowchart which shows the process of the radio | wireless packet communication system (Embodiment 4) of this invention with FIG.21 and FIG.23. It is a flowchart which shows the process of the radio | wireless packet communication system (Embodiment 4) of this invention with FIG.21 and FIG.22. It is a block diagram which shows the structure of terminal T1d-T3d in Embodiment 5 of this invention. It is a flowchart which shows the process of the wireless packet communication system (Embodiment 5) of this invention with FIG. It is a flowchart which shows the process of the wireless packet communication system (Embodiment 5) of this invention with FIG.

Explanation of symbols

10 Network 20, 20a, 20b, 20c Load balancer 30 Internet T1-T3, T1a-T3a, T1c-T3c, T1d-T3d Terminals B1-B3, B1a-B3a, B1b-B3b Base station 71 Communication monitor 711 Communication identification Timer 72, 72b Terminal management table 73, 73b Channel management table 74, 55, 82 Channel decision unit 77, 58 Reception strength / transmission rate correspondence table 78, 81 Throughput calculator

Claims (5)

In a wireless packet communication system for transmitting packets between a plurality of base stations and terminals via any of a plurality of channels,
A terminal management table that stores the terminal identification information of the source or destination terminal of the captured packet for each channel together with the transmission rate of the packet as terminal identification information of the terminal in communication;
It has a plurality of timers that repeatedly measure a predetermined period, assigns one of the plurality of timers to each terminal whose terminal identification information is stored in the terminal management table, and sets the communication state of each channel for each predetermined period A communication state detection means for detecting;
Channel selection means for selecting a channel for newly starting communication according to the communication status of each channel detected by the communication status detection means,
The communication state detecting means includes
For a terminal whose terminal identification information is stored in the terminal management table, when a packet originating or arriving at the terminal was captured before the assigned timer expired, the timer was reset and not captured In this case, regarding the terminal, it is determined that the communication is terminated, and the terminal identification information is deleted from the terminal management table and the timer is released.
The channel selection means includes
The number of terminal identification information for each channel stored in the terminal management table and the transmission rate corresponding to the terminal identification information are acquired, and the acquired number of terminal identification information for each channel and the terminal identification information are Based on the corresponding transmission rate, the throughput of each channel is calculated, and using the calculation result of the throughput, it is assumed that the terminal that newly made a communication request uses, between the plurality of base stations and the terminal 2 estimate the throughput of all the two or more channels used for packet transmission, and select the channel with the highest throughput among the estimation results as the channel used by the terminal that newly requested the communication. A wireless packet communication system. The wireless packet communication according to claim 1 , wherein the communication state detection means identifies each communication based on at least one of a source address and a destination address included in a packet transmitted and received between a base station and a terminal. system. A part or all of each component of the communication state detection means is distributed or concentrated in either a base station or a load distribution apparatus provided in common to a plurality of base stations,
Some or all of the components of the channel selection means are distributed or concentrated in any one of a base station, a terminal, or a load distribution apparatus provided in common to a plurality of base stations. The wireless packet communication system according to claim 1 , wherein the wireless packet communication system is a wireless packet communication system. The radio packet communication system according to any one of claims 1 to 3 , wherein the plurality of channels include two or more transmission schemes. In a wireless packet communication method for transmitting packets between a plurality of base stations and terminals via any of a plurality of channels,
The terminal identification information of the source or destination terminal of the captured packet is stored in the terminal management table for each channel together with the transmission rate of the packet as the terminal identification information of the communicating terminal, and the terminal identification information is stored in the terminal management table A communication state detection process for detecting a communication state of each channel for each predetermined period by assigning a timer that repeatedly measures a predetermined period for each terminal being used;
A channel selection process for selecting a channel for newly starting communication according to the communication status of each channel detected in the communication status detection process,
In the communication state detection process,
For a terminal whose terminal identification information is stored in the terminal management table, when a packet originating or arriving at the terminal was captured before the assigned timer expired, the timer was reset and not captured In this case, regarding the terminal, it is determined that the communication is terminated, and the terminal identification information is deleted from the terminal management table and the timer is released.
In the channel selection process,
The number of terminal identification information for each channel stored in the terminal management table and the transmission rate corresponding to the terminal identification information are acquired, and the acquired number of terminal identification information for each channel and the terminal identification information are Based on the corresponding transmission rate, the throughput of each channel is calculated, and using the calculation result of the throughput, it is assumed that the terminal that newly requested the communication uses, and between the plurality of base stations and the terminal 2 estimate the throughput of all the two or more channels used for packet transmission, and select the channel with the highest throughput among the estimation results as the channel used by the terminal that newly requested the communication. A wireless packet communication method characterized by:

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