Wireless base station, control method, and program

Abstract

To provide a radio base station, a control method, and a program, for suppressing deterioration of a throughput.SOLUTION: A radio base station comprises: a first communication part 201 that transmits and receives a communication frame in a space of radio terminals wired; a second communication part 202 that transmits and receives the communication frame in a space of the other radio terminals; a storage part 203 that stores radio terminal information as information related to a radio communication acquired at the time of performing a radio connection processing with each radio terminal; a transfer part 204 that determines whether or not a transmission destination address of the communication frame notified from the first communication part 201 or the second communication part 202 is an address of each of the radio terminals under an own device; a change part 205 that changes priority order information stored in a ToS field of the communication frame on the basis of a notification of the transfer part 204; and a control part 206 that controls the communication frame processed by te changing part 205 on the basis of the notification of the transfer part 204 so as to is transmitted toward each radio terminal of a transmission destination address from the first communication part 201 or the second communication part 202.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a radio base station, a control method, and a program therefor. [Background technology]

[0002] To ensure a wide wireless communication range, WDS (Wireless Distribution System) communication has been known. This technology involves placing multiple wireless base stations (e.g., wireless access points) within the radio wave range of each device and relaying each other's wireless communications. A wireless base station in WDS communication can achieve both communication with wireless terminals (infrastructure communication) and wireless communication between wireless base stations with a relatively simple configuration by using only a single wireless interface. However, WDS communication requires that all wireless terminals and wireless base stations use the same wireless channel. This creates a problem: As the number of wireless terminals and wireless base stations increases or the communication load becomes high, the communication bandwidth between wireless base stations becomes constricted, significantly reducing throughput and degrading the quality of wireless communication.

[0003] In order to solve such problems, the technology disclosed in Patent Document 1 suppresses a decrease in throughput in wireless communication between multiple wireless communication base stations and maintains high communication performance by using different frequency channels for relaying wireless transmission and relaying wireless reception at one wireless communication base station in wireless communication between multiple wireless communication base stations. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-172283 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the wireless communication base station of the wireless communication system disclosed in Patent Document 1, wireless communication between multiple wireless communication base stations is performed using different channels for relay wireless transmission and relay wireless reception, and therefore, as the number and locations of wireless communication base stations increase, the number of channels required for wireless communication also increases. Therefore, for example, in an environment where there are already few channels available for wireless communication (e.g., many existing wireless communication devices, channels are predetermined, etc.), the wireless communication base station is not suitable for wireless communication (WDS communication) between multiple wireless communication base stations. Furthermore, the wireless communication base station must have vendor-specific functions, which reduces versatility and reduces user convenience.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a radio base station in a communication system consisting of multiple radio base stations that suppresses a decrease in throughput, maintains high communication performance, and also takes user convenience into consideration. [Means for solving the problem]

[0007] In order to solve the above problem, a radio base station according to one aspect of the present invention is a radio base station in a communication system in which a plurality of radio base stations perform radio communication with each other and subordinate radio terminals connected to each radio base station perform radio communication, the radio base station comprising: a first communication unit that transmits and receives communication frames to and from the subordinate radio terminals; and a second communication unit that transmits and receives communication frames to and from other radio base stations; subordinates The device is equipped with a memory unit that stores wireless terminal information, which is information related to wireless communication obtained during wireless connection processing with a wireless terminal; a forwarding unit that determines whether the destination address of a communication frame notified from the first communication unit or the second communication unit is the address of each wireless terminal under the device; a modification unit that modifies the priority information to be stored in the ToS field of the communication frame based on the notification from the forwarding unit; and a control unit that controls the communication frame processed by the modification unit to be transmitted from the first communication unit or the second communication unit to the wireless terminal at the destination address based on the notification from the forwarding unit.

[0008] According to this, in wireless communication between multiple wireless base stations, the wireless base station can secure sufficient communication bandwidth by giving a higher priority to wireless communication between adjacent wireless base stations, thereby suppressing a decrease in throughput in wireless communication between multiple wireless communication base stations.

[0009] Further, the change unit changes the destination address of the communication frame notified by the transfer unit from the first communication unit if the destination address is not an address of a wireless terminal under the own device. The priority information to be stored in the ToS field of Send with at least medium priority.

[0010] This allows a wireless base station to perform wireless communication with an adjacent wireless base station with higher priority than wireless communication with a wireless terminal under its control.

[0011] Furthermore, when the forwarding unit determines that the destination address of the communication frame notified by the second communication unit is addressed to a wireless terminal under the control of the device, the change unit may rewrite the priority information stored in the ToS field of the communication frame to medium (best effort).

[0012] This allows the wireless base station to perform wireless communication with the wireless terminals under its control with appropriate priority.

[0013] Furthermore, if the forwarding unit determines that the destination address of the communication frame notified by the second communication unit is not addressed to a wireless terminal under the control of the device, the change unit may transmit the communication frame to another adjacent wireless base station without rewriting the priority information stored in the ToS field of the communication frame.

[0014] This allows the wireless base station to autonomously control wireless communication between adjacent wireless base stations so that it has a higher priority than wireless communication between wireless terminals under its control.

[0015] Furthermore, a control method according to one aspect of the present invention is a control method for a radio base station in a communication system in which a plurality of radio base stations perform radio communication with each other and subordinate radio terminals connected to each radio base station perform radio communication, the control method including: a first communication step of transmitting and receiving communication frames to and from subordinate radio terminals; and a second communication step of transmitting and receiving communication frames to and from another radio base station. subordinates The method may include a storage step of storing wireless terminal information, which is information related to wireless communication obtained during wireless connection processing with a wireless terminal; a transfer step of determining whether the destination address of the communication frame notified from the first communication step or the second communication step is the address of each of the wireless terminals subordinate to the device; a modification step of modifying the priority information stored in the ToS field of the communication frame based on the notification from the transfer step; and a control step of controlling the communication frame processed in the modification step to be transmitted from the first communication step or the second communication step to the wireless terminal at the destination address based on the notification from the transfer step.

[0016] According to this, the control method has the same effect as the above-mentioned wireless base station.

[0017] A program according to one aspect of the present invention is a program for causing a computer to execute the above control method.

[0018] According to this, the program has the same effect as the above-mentioned wireless base station. [Effects of the Invention]

[0019] According to the present invention, a radio base station or the like can suppress a decrease in throughput and maintain high communication performance in a communication system in which a plurality of radio base stations communicate with each other by radio. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram illustrating an overview of a communication system according to an embodiment. [Figure 2]FIG. 2 is a block diagram illustrating a functional configuration of a radio base station according to an embodiment. [Figure 3] FIG. 3 is a flowchart showing the operation of the radio base station according to the embodiment. [Figure 4] FIG. 4 is an explanatory diagram illustrating an example of a radio frame transmitted and received between the radio base station according to the embodiment and another radio base station. [Figure 5] FIG. 5 is an explanatory diagram illustrating an example of priority information stored in a radio frame transmitted by a radio base station according to the embodiment. [Figure 6] FIG. 6 is an explanatory diagram showing an example of the operation of the wireless base station according to the embodiment, in which processing is performed based on the source address and destination address of a communication frame in different cases. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, the embodiments will be specifically described with reference to the drawings. The embodiments described below each illustrate a preferred specific example of the present invention. The numerical values, shapes, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concept of the present invention will be described as optional components that constitute a more preferred embodiment. Note that identical components will be assigned the same reference numerals, and descriptions thereof may be omitted.

[0022] (Embodiment) In this embodiment, a radio base station or the like that suppresses a decrease in throughput and maintains high communication performance in a communication system in which a plurality of radio base stations communicate with each other by radio will be described.

[0023] FIG. 1 is a schematic diagram showing an overview of a communication system 100 according to the present embodiment.

[0024] 1, a communication system 100 includes wireless base stations 1a, 1b, and 1c, wireless terminals 11a and 11b, a wireless terminal 12, a wireless communication link 15, and a wireless communication link 16. The communication system 100 is a wireless communication system installed in, for example, a factory or an office. Hereinafter, the wireless base stations 1a, 1b, and 1c will also be collectively referred to as wireless base station 1. The wireless base stations 11a and 11b will also be collectively referred to as wireless terminal 11.

[0025] In this embodiment, the communication system 100 includes three wireless base stations 1a, 1b, and 1c, but is not limited to this and may include four or more wireless base stations. In this embodiment, the communication system 100 includes wireless terminals 11a and 11b and wireless terminal 12, but is not limited to this and may include a configuration in which multiple wireless terminals are connected to each wireless base station 1.

[0026] The wireless base station 1 performs wireless communication with the wireless terminals 11 and 12 via a wireless communication link 16. As shown in Fig. 1, the wireless base station 1a performs wireless communication by transmitting and receiving wireless frames to and from each of the wireless terminals 11 via the wireless communication link 16. The wireless base station 1a also relays wireless frames transmitted from the wireless terminal 11a to the wireless terminal 11b via the wireless communication link 16, and conversely, relays wireless frames transmitted from the wireless terminal 11b to the wireless terminal 11a. The wireless base station 1 is, for example, a wireless access point.

[0027] The wireless terminals 11 and 12 connect to the wireless base station 1 and perform wireless communication in accordance with a wireless communication standard such as IEEE802.11ac. The wireless terminals 11 and 12 are, for example, personal computers or smartphones.

[0028] The wireless communication link 15 is a communication path for wireless communication between each of the wireless base stations 1. The wireless communication link 15 may also be configured as WDS communication. The wireless communication link 15 complies with a wireless communication standard such as IEEE802.11ac, and performs wireless communication between each of the wireless base stations 1 using, for example, a frequency band of 2.4 GHz. The communication standard and frequency band used in the wireless communication link 15 are not limited to IEEE802.11ac and 2.4 GHz, and may be any wireless communication standard and frequency band that can be processed by a wireless circuit provided in each of the wireless base stations 1.

[0029] The wireless communication link 16 is a communication path when the wireless base station 1 performs wireless communication with each of the subordinate wireless terminals 11 and 12, and operates in, for example, infrastructure mode. Furthermore, the wireless communication link 16 preferably complies with a wireless communication standard such as IEEE802.11ac and performs wireless communication using, for example, a frequency band different from that used by the wireless communication link 15. Note that the communication standard used by the wireless communication link 16 may be any wireless communication standard and frequency band that can be processed by the wireless circuits provided in the wireless base station 1 and the wireless terminal 11, respectively.

[0030] 2 is a block diagram showing the functional configuration of wireless base station 1 according to this embodiment. Wireless base station 1 includes first communication unit 201, second communication unit 202, storage unit 203, transfer unit 204, change unit 205, and control unit 206. Wireless base station 1 is a type of computer, and a CPU (Central Processing Unit) works in cooperation with each piece of hardware to load a program stored in storage unit 203 into a main storage unit and execute the program.

[0031] The first communication unit 201 transmits and receives communication frames to and from each of the wireless terminals 11 and 12 subordinate to the wireless base station 1 (its own device). The first communication unit also determines whether or not a communication frame has been received from each of the wireless terminals 11 and 12 subordinate to the wireless base station 1. The first communication unit 201 is realized by a wireless module, an antenna (not shown), a driver program for the wireless module, etc., and performs wireless communication with each of the wireless terminals 11 and 12 subordinate to the first communication unit 201 in accordance with a wireless communication standard such as IEEE802.11ac.

[0032] The second communication unit 202 transmits and receives communication frames to and from other wireless base stations 1. The second communication unit also determines whether or not a communication frame has been received from another wireless base station. The second communication unit 202 is realized by a wireless module, an antenna (not shown), a driver program for the wireless module, and the like, which are separate from those constituting the first communication unit, and performs wireless communication with other wireless base stations 1 in accordance with a wireless communication standard such as IEEE802.11ac.

[0033] The storage unit 203 stores various setting information related to wireless communication, information to be temporarily stored in communication processing, etc. Specifically, the storage unit 203 stores device information of its own device (wireless base station 1) (e.g., the channel used for wireless communication, BSSID, SSID, authentication method, encryption method, etc.). The storage unit 203 also stores information on subordinate wireless terminals to which the own device can connect. The wireless terminal information is, for example, information related to wireless communication acquired during wireless connection processing with a wireless terminal (e.g., the MAC address, IP address, security information, etc. of the wireless terminal). The storage unit 203 may be realized by a volatile storage device such as a RAM, or may be realized by a non-volatile storage device such as an eMMC (Embedded Multimedia Card), an SSD (Solid State Drive), or an HDD (Hard Disk Drive). The storage unit 203 also stores IP presence density values ​​in association with access categories, as will be described later.

[0034] The forwarding unit 204 determines whether the destination address of the communication frame notified by the first communication unit is the address of each of the wireless terminals 11 and 12 (for example, wireless terminal 11b) subordinate to the own device. Specifically, the forwarding unit 204 makes this determination by referring to the header information of the communication frame and the wireless terminal information subordinate to the own device stored in the storage unit 203. The forwarding unit 204 notifies the control unit 206 to transmit the communication frame notified by the change unit 205 to the wireless terminal (for example, wireless terminal 12) listed in the destination address via the first communication unit or the second communication unit. The forwarding unit 204 may be in the form of a computer realized by a CPU, a RAM (Random Access Memory), etc., or may be realized in the form of a program that achieves the same determination effect.

[0035] The change unit 205 performs processing to change the access category (details will be described later) to be stored in the ToS field of the communication frame based on the notification from the forwarding unit 204, and returns the result to the forwarding unit 204. Specifically, based on the notification from the forwarding unit 204, the change unit 205 rewrites the IP precedence value to be stored in the ToS field of the IP header of the communication frame to an IP precedence value corresponding to the access category. When the change unit 205 changes the IP precedence value to be stored in the ToS field, it also recalculates the checksum value of the IP header. The change unit 205 may be in the form of a computer realized by a CPU, RAM, etc., or may be realized in the form of a program that achieves the same determination effect.

[0036] The control unit 206 controls the first communication unit to transmit the communication frame processed by the change unit 205 to the wireless terminal of the destination address based on the notification from the forwarding unit 204. The control unit 206 also controls the second communication unit to transmit the communication frame processed by the change unit 205 to the adjacent wireless base station to the wireless terminal of the destination address based on the notification from the forwarding unit 204. The control unit 206 may be in the form of a computer realized by a CPU, a RAM (Random Access Memory), or the like, or may be realized in the form of a program that has the same determination effect.

[0037] Next, communication using WMM (Wi-Fi Multimedia) in the wireless base station 1 according to this embodiment will be described in detail with reference to Figures 4 and 5. WMM is a known technology that is a function of Wi-Fi (registered trademark) that sets priorities and prioritizes specific communications when multiple types of data handled over a wireless LAN are simultaneously transmitted and received.

[0038] FIG. 4 shows an example of a communication frame (Ethernet frame) in the communication system 1 according to the present embodiment.

[0039] The Ethernet frame 40 shown in Figure 4 represents a packet sent and received in TCP / IP communications and is primarily composed of an Ethernet header, IP header, TCP header, variable-length data, and FCS (Frame Check Sequence). The IP header of the Ethernet frame 40 further comprises fields such as version 41, header length 42, ToS (Type of Service) 43, options 44, and padding 45. The version 41 stores the IP version. The header length 42 stores the size of the IP header. ToS 43 is used to assign priority to IP packets, and the first three (highest) bits of the eight-bit data contain the IP precedence. IP precedence is divided into eight levels, from 0 to 7, with higher values ​​indicating higher priority for the frame. Options 44, if any, such as timestamps or source routing, are stored here. Padding 45 is used to pad the IP header with zeros so that it fits within a multiple of four (e.g., 32 bits).

[0040] In the wireless base station 1 of this embodiment, the IP precedence values ​​to be set in ToS43 included in the IP header shown in Figure 4 are associated with each access category used in WMM shown in Figure 5, which will be explained next, and are stored in advance in the storage unit 203.

[0041] 5 is a list showing priorities used by the wireless base station 1 according to this embodiment to identify the priority of a communication frame. The priority information 50 is stored in the storage unit 203 of the wireless base station 1, and is priority information that is referenced based on notifications from the transfer unit 204 and the change unit 305. The priority information 50 shows the relationship between the access categories to which bandwidth is allocated in descending order of priority in WMM, and the priorities (four levels from highest to lowest) defined for the access categories.

[0042] The access category is information that indicates the type of communication (traffic type 52) of IP packets in communications using WMM. Specifically, there are four access categories as shown in Figure 5, and four levels of priority 51 are defined for IP packets. Voice (AC_VO) is assigned to IP packets related to voice communication. The priority 51 of AC_VO is 1 (the highest), the highest of the four. Video (AC_VI) is assigned to IP packets related to video. The priority 51 of AC_VI is 2 (high). Best effort (AC_BE) is assigned to IP packets that should be communicated on a best-effort basis. AC_BE is assigned to IP packets of normal data that require less immediacy than voice and video. The priority 51 of AC_BE is 3 (medium). Background (AC_BK) is assigned to IP packets that should be communicated in the background. AC_BK is assigned to IP packets of data that have no restrictions on the transmission time (especially large amounts of data that take a long time to communicate), for example. The priority 51 of AC_BK is 4, which is the lowest priority (lowest). The four access categories are assigned priorities according to the IP precedence value set in the ToS field in the IP header shown in Figure 4. For example, the IP precedence value "111" is set for the access category AC_VO (highest), the IP precedence value "011" is set for AC_BE (medium), and the IP precedence value "001" is set for AC_BK (low).

[0043] In the communication system 100 of this embodiment, a network is constructed that is made up of a plurality of wireless base stations 1 and that allows wireless communication between adjacent wireless base stations 1. When wireless communication is performed from a wireless terminal under a specified wireless base station 1 via the device itself to a wireless terminal under another wireless base station 1, and when wireless communication is performed from a wireless terminal under a specified wireless base station 1 via the device itself to another wireless terminal under the device itself, the operations according to the respective wireless communication environments will be described in detail below with reference to Figures 3 and 6.

[0044] FIG. 3 is a flowchart showing an example of the operation of the wireless base station 1 according to the present embodiment.

[0045] In step S301, the first communication unit 201 or the second communication unit 202 of the wireless base station 1 determines whether or not a communication frame has been received. If the first communication unit 201 or the second communication unit 202 has received a communication frame, the process proceeds to step S302 (Yes in step S301). On the other hand, if the communication frame has not been received, step S301 is repeated and the wireless base station 1 enters a reception waiting state (No in step S301).

[0046] In step S302, the first communication unit 201 or the second communication unit 202 determines whether it has received a communication frame from a subordinate wireless terminal 11 or from another wireless base station. If the first communication unit 201 has received a communication frame from a subordinate wireless terminal 11, it notifies the forwarding unit 204 of the destination address of the communication frame and proceeds to step S303 (step S302(a)). On the other hand, if the second communication unit 202 has received a communication frame from another wireless base station 1, it notifies the forwarding unit 204 of the destination address of the communication frame and proceeds to step S304 (step S302(b)).

[0047] In step S303, forwarding unit 204 determines whether the destination address of the communication frame notified from first communication unit 201 is the address of wireless terminal 11 (for example, wireless terminal 11b) subordinate to its own device. If the destination address matches the address of wireless terminal 11 subordinate to its own device, forwarding unit 204 transitions to step S306 (Yes in step S303). On the other hand, if the destination address does not match the address of wireless terminal 11 subordinate to its own device, forwarding unit 204 notifies change unit 205 to that effect, and transitions to step S305 (No in step S303).

[0048] In step S305 (i.e., in the case of a frame to be transmitted from a subordinate communication terminal to another wireless base station), the change unit 205 causes the communication frame to be transmitted with at least medium or higher priority. Specifically, based on the notification from the forwarding unit 204 (No in step S303), the change unit 205 rewrites the IP precedence value stored in Tos43 of the communication frame to change the access category to medium or higher. For example, the change unit 205 performs a process of rewriting the IP precedence value to an IP precedence value (e.g., "111") corresponding to AC_VO (Voice), which is the highest priority, and recalculates the checksum value of the IP header. The change unit 205 notifies the forwarding unit 204 of the communication frame after this process, and the process proceeds to step S307.

[0049] In step S304, the forwarding unit 204 determines whether the destination address of the communication frame notified by the second communication unit 202 is addressed to a wireless terminal subordinate to the own device. More specifically, the determination is made by referring to the wireless terminal information subordinate to the own device stored in the storage unit 203. If the destination address of the communication frame is addressed to a wireless terminal subordinate to the own device, the forwarding unit 204 notifies the change unit 205 to that effect and proceeds to step S306 (Yes in step S304). On the other hand, if the destination address is not addressed to a wireless terminal subordinate to the own device, the change unit 205 notifies the forwarding unit 204 of the communication frame and proceeds to step S307 (No in step S304). In this case, the IP precedence value should have already been changed to the highest value by another wireless base station in the system, and is not rewritten.

[0050] In step S306 (i.e., in the case of a frame whose destination is a subordinate communication terminal), the change unit 205 performs a process of rewriting the IP precedence value stored in ToS43 of the communication frame to an IP precedence value (e.g., "011") corresponding to AC_BE (Best Effort), which is the middle access category, based on the notification from the forwarding unit 204 (Yes in step S304), and recalculates the checksum value of the IP header. The change unit 205 notifies the forwarding unit 204 of the communication frame after this processing, and the process proceeds to step S308.

[0051] In step S307, the forwarding unit 204 notifies the control unit 206 to transmit the communication frame notified by the change unit 205 in step 305 (the communication frame whose priority has been rewritten to medium or higher) from the second communication unit 202 to the wireless terminal of the destination address (e.g., wireless terminal 12) (i.e., notify the control unit 206 to transmit the communication frame notified by the change unit 205 in step 304 (i.e., the communication frame received from the other wireless base station 1) from the second communication unit 202 to the wireless terminal of the destination address (e.g., wireless terminal 12) (i.e., notify the control unit 206 to transmit the communication frame notified by the change unit 205 in step 304 (i.e., the communication frame received from the other wireless base station 1) (i.e., notify the control unit 206 to transmit the communication frame to the wireless terminal of the destination address via the other wireless base station 1). Based on the notification from the forwarding unit 204, the control unit 206 controls the second communication unit 202 to transmit the frame to the wireless terminal of the destination address. Thereafter, the second communication unit 202 transmits the communication frame to an adjacent wireless base station (for example, wireless base station 11b).

[0052] In step S308, forwarding unit 204 notifies control unit 206 to transmit the communication frame notified by change unit 205 in step S306 (the communication frame whose priority has been rewritten to medium) from first communication unit 201 to a wireless terminal (e.g., wireless terminal 11b) at the destination address. Based on the notification from forwarding unit 204, control unit 206 controls first communication unit 201 to transmit the frame to a wireless terminal (e.g., wireless base station 11b) at the destination address. Thereafter, first communication unit 201 transmits the communication frame to a wireless terminal (e.g., wireless base station 11b) subordinate to its own device.

[0053] Here, the processing performed by the change unit 205 based on the source address and destination address of the communication frame in the series of operations of the wireless base station 1 performed from step S302 to step S306 shown in FIG. 3 is summarized using FIG.

[0054] FIG. 6 is an explanatory diagram showing an example of a series of operations of the wireless base station 1 according to the embodiment, in which processing is performed based on the source address and destination address of a communication frame in different cases.

[0055] When the source address of the communication frame is (a) a subordinate wireless terminal and the destination address is transmitted to a wireless terminal via another wireless base station (specifically, an adjacent wireless base station) (No in step S303 in Figure 3), the change unit 205 performs a process of rewriting the IP precedence value stored in ToS43 of the communication frame to an IP precedence value corresponding to (1) the access category AC_VO (Voice).

[0056] When the source address of the communication frame is (a) a subordinate wireless terminal and the destination address is sent to a subordinate wireless terminal (specifically, another subordinate wireless terminal 11) (Yes in step S303 of Figure 3), the change unit 205 performs a process of rewriting the IP precedence value stored in ToS43 of the communication frame to (2) an IP precedence value corresponding to the access category AC_BE (Best Effort).

[0057] When the source address of the communication frame is (b) another wireless base station (specifically, from a wireless terminal 11 under the control of another wireless base station) and the destination is transmitted to a wireless terminal via another wireless base station (specifically, an adjacent wireless base station) (No in step S304 in FIG. 3), the change unit 205 performs processing to notify the forwarding unit 204 of the communication frame. That is, the change unit 205 notifies the forwarding unit 204 of the ToS 43 of the communication frame received by the second communication unit 202 (3) without changing it. The IP precedence value in this frame has already been rewritten by another wireless base station in this system to an IP precedence value corresponding to the access category AC_VO (Voice).

[0058] When the source address of the communication frame is (b) another wireless base station (specifically, from a wireless terminal 12 under the control of another wireless base station) and the destination address is sent to a subordinate wireless terminal (specifically, another subordinate wireless terminal 11) (Yes in step S304 of Figure 3), the change unit 205 performs a process of rewriting the IP precedence value stored in ToS43 of the communication frame to an IP precedence value corresponding to (2) access category AC_BE (Best Effort).

[0059] (summary) In conventional wireless communications conforming to WMM, an access category is automatically determined according to the type of IP packet (traffic type, such as voice or video) transmitted from a wireless terminal, and a wireless base station controls the wireless communications. In this regard, in the wireless base station 1 according to the present embodiment, when the wireless base station 1 relays communication frames transmitted from the wireless terminals 11 and 12, (1) when a wireless terminal 11 (e.g., wireless terminal 11a) subordinate to the wireless base station 1a communicates with a wireless terminal 12 subordinate to another wireless base station 1 (e.g., wireless base station 1c), the wireless base station 1 rewrites the IP precedence value in the ToS 43 in the IP header of the communication frame to a value corresponding to AC_VO, which is the highest access category (priority 1), regardless of the actual traffic type, and transmits the communication frame to an adjacent wireless base station 1 (e.g., wireless base station b). As a result, in the communication system according to the present embodiment, each wireless base station can autonomously control the wireless communications between adjacent wireless base stations so that the priority is higher than that of wireless communications between wireless terminals subordinate to the wireless base station 1a. Therefore, in the communication system of the embodiment, a sufficient communication bandwidth can be secured for wireless communication (e.g., WDS communication) between multiple wireless base stations, and a decrease in throughput in wireless communication between multiple wireless communication base stations can be suppressed. On the other hand, (2) when a wireless terminal 11 (e.g., wireless terminal 11a) under its own device (e.g., wireless base station 1a) communicates with another wireless terminal 11 (e.g., wireless terminal 11b) under its own device, the IP precedence value in ToS43 in the IP header of the communication frame is rewritten to a value corresponding to AC_BE, which is the middle access category (priority level 3), and transmitted to the other wireless terminal 11 under its own device. As a result, in the communication system of the embodiment, wireless communication between multiple wireless base stations can be prioritized, and a decrease in throughput in wireless communication between multiple wireless communication base stations can be suppressed. [Industrial Applicability]

[0060] The present invention can be used for wireless communication between wireless base stations in a communication system made up of a plurality of wireless base stations, and more specifically, can be applied to wireless base stations that can suppress a decrease in throughput. [Explanation of symbols]

[0061] 100 Communication Systems 1a, 1b, 1c wireless base station 11a, 11b, 12 Wireless terminal 15,16 Communication Links 201 First Communications Department 202 Second Communications Department 203 Storage section 204 Transfer Department 205 Changes 206 Control Unit 41 versions 42 Header Length 43 ToS (Type of Service) 44 Options 45 padding 50 Priority Information 51 Priority 52 Traffic Types

Claims

1. A radio base station in a communication system in which a plurality of radio base stations perform radio communication with each other and subordinate radio terminals connected to each radio base station perform radio communication, a first communication unit that transmits and receives communication frames to and from the subordinate wireless terminal; a second communication unit that transmits and receives communication frames to and from other wireless base stations; a storage unit for storing wireless terminal information, which is information relating to wireless communication acquired during wireless connection processing with the subordinate wireless terminal; a transfer unit that determines whether or not a destination address of a communication frame notified from the first communication unit or the second communication unit is an address of each of the wireless terminals under the control of the own device; a change unit that changes priority information to be stored in a ToS field of the communication frame based on a source address and a destination address of the communication frame upon receiving a notification of the determination result of the transfer unit; a control unit that controls the communication frame processed by the change unit based on the notification from the transfer unit so that the communication frame is transmitted from the first communication unit or the second communication unit to a wireless terminal having a destination address; A radio base station comprising:

2. When the destination address of the communication frame notified to the forwarding unit by the first communication unit is not an address of the wireless terminal under the own device, the change unit causes the priority information to be stored in the ToS field of the communication frame to be transmitted with at least a medium or higher priority. The radio base station according to claim 1.

3. The modification unit further When the forwarding unit determines that the destination address of the communication frame notified from the second communication unit is addressed to the wireless terminal under the own device, the priority information stored in the ToS field of the communication frame is rewritten to medium (best effort). The radio base station according to claim 2.

4. The modification unit further When the transfer unit determines that the destination address of the communication frame notified from the second communication unit is not addressed to the wireless terminal under the own device, the transfer unit transmits the communication frame to another adjacent wireless base station without rewriting the priority information stored in the ToS field of the communication frame. The radio base station according to claim 2.

5. A method for controlling a radio base station in a communication system in which a plurality of radio base stations perform radio communication with each other and subordinate radio terminals connected to each radio base station perform radio communication, comprising: a first communication step of transmitting and receiving a communication frame to and from the subordinate wireless terminal; a second communication step of transmitting and receiving communication frames to and from another wireless base station; a storage step of storing wireless terminal information, which is information regarding wireless communication acquired during wireless connection processing with the subordinate wireless terminal; a transfer step of determining whether or not the destination address of the communication frame notified from the first communication step or the second communication step is the address of each of the wireless terminals under the control of the own device; a modifying step of modifying priority information stored in a ToS field of the communication frame based on a source address and a destination address of the communication frame upon receiving notification of the determination result of the forwarding step; a control step of controlling the communication frame processed in the change step based on the notification of the transfer step so that the communication frame is transmitted from the first communication step or the second communication step to the wireless terminal of the destination address; A control method comprising:

6. A program for causing a computer to execute the control method according to claim 5.

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