JP2006174155A - Wireless base station and its wireless relay method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless base station capable of obtaining throughput similar to the packet of the large size, even if communication service using a protocol for making a reservation for a wireless channel is performed, and to provide its wireless relay method. <P>SOLUTION: Each of wireless stations 18-26 is made to have a relay function with respect to adjoining wireless stations, by lapping the communication ranges of the adjoining wireless stations over each other respectively, judges the existence of an encapsulated packet by an analysis by a packet analysis 52, decomposes the encapsulated packet by a packet release 54 individually, searches for a packet addressed to the same wireless station on the basis of route information which a routing table 56 stores and destination information which the packet has in a relay controller 58, integrates a plurality of detected packets addressed to the same wireless station into one packet by a capsule former 62 in accordance with the detection of the plurality of packets, and transmits it to the adjoining wireless stations. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radio base station and a radio relay method thereof. The radio base station of the present invention relates to the field of relay base stations in a multi-hop radio communication system applied to a wireless LAN (Local Area Network) defined by, for example, the IEEE 802.11 standard. The radio relay method of the present invention relates to the field of packet transmission between radio stations in a multi-hop radio communication system, for example.

  A wireless communication system compatible with a multi-hop network includes a plurality of wireless stations having a relay function, and these wireless stations form a network. Communication in this system relays a packet supplied by an adjacent radio station and transfers the packet to a radio station far away where radio waves do not reach.

In this wireless communication system, a CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) method is well known as a media access control technique for transmitting packets. In this CSMA / CA scheme, when a certain wireless station attempts to transmit a packet, this wireless station performs carrier sense for detecting a carrier of a wireless signal transmitted by another wireless station. When a carrier is detected, it waits for packet transmission from its own station until no carrier is detected. Further, when the carrier is not detected, the packet can be transmitted. However, after the carrier is not detected, the radio station transmits the packet after a random waiting time has elapsed. If the wireless station that is the transmission source does not receive a response confirmation packet from the destination wireless station after packet transmission, the wireless station determines that the packet has collided with a packet of another wireless station. The wireless station retransmits the packet after a random waiting time has elapsed after receiving this result.
JP 2002-124953 A

  Using the CSMA / CA method described above, when a multi-hop network is formed and a plurality of radio stations using the same radio channel frequently relay packets, each radio station in the radio communication system is used for carrier sense. There is a problem that the throughput of information decreases due to an increase in waiting time, loss of packets due to packet collisions, and an increase in retransmission packets.

  A wireless packet relay method, a wireless packet relay system, and a wireless station in Patent Document 1 reserve a packet transmission right defined in the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard in a wireless local area network (LAN). RSV (ReSerVation) packet that reserves a radio channel ahead of the relay radio station is newly incorporated in the RTS (Request To Send) / CTS (Clear To Send) mechanism. As a result, the relay radio station can relay the packet with low delay without waiting for the radio channel at the relay destination to become free.

  By the way, a relay radio station using a wireless communication scheme using CSMA / CA may have different throughputs depending on the size of a packet to be transmitted. For example, even when the same amount of data is transmitted, if one packet size is small, the total number of packets generated increases. An overhead such as an address and control information is added to the generated packet. For this reason, as the number of packets increases, the ratio of overhead per packet increases. As a result, the total amount of data to be transmitted increases and the throughput decreases. When transmitting one packet, the radio station needs a random waiting time when performing carrier sense. As a result, when the number of packets increases, the wireless communication system also increases the overall waiting time in wireless communication, which causes a reduction in system throughput. As an application in which packets of such a small size are continuously transmitted, a VoIP (Voice over IP) service that transmits voice as IP (Internet Protocol) packets can be considered.

  The present invention eliminates the drawbacks of the prior art, and even when a communication service using a protocol for reserving a radio channel is implemented, a radio base station capable of obtaining the same throughput as a large packet and its radio The purpose is to provide a relay method.

  In order to solve the above-mentioned problem, the present invention arranges communication ranges of adjacent wireless base stations so as to overlap each other among wireless base stations in wireless communication, and wirelessly communicates packets with adjacent wireless base stations. By communicating, in each radio base station having a relay function in communication of this packet, the radio base station determines whether or not the received packet is an encapsulated packet including a plurality of packets. Analyzing means for analyzing the packet, release means for decomposing the encapsulated packet into individual packets, route storage means for storing route information for relaying the received packet to the communication partner via the radio base station, Determine whether there are multiple packets addressed to the same base station based on the destination information and route information of each received packet That the determining means, in accordance with the determination result in which a plurality of packets to be sent to the same base station is present, characterized in that it comprises an integrated unit for integrating into packets one corresponding to this determination.

  The radio base station according to the present invention has a function of relaying each radio base station to an adjacent radio base station by overlapping the communicable ranges of adjacent radio base stations among a plurality of radio base stations. The presence / absence of the encapsulated packet is determined by analysis by the analysis unit, the packet encapsulated by the release unit is individually decomposed, and the determination unit is the same based on the path information and destination information stored in the path storage unit The presence or absence of packets addressed to the base station is searched and determined, and the amount of overheader is reduced by integrating the packets detected by the integration means into one packet in response to a plurality of detections of packets addressed to the same radio station.

  In order to solve the above-described problem, the present invention provides a relay method for relaying packets by wirelessly communicating with adjacent wireless base stations. This method includes a capsule in which a received packet includes a plurality of packets. A first step of analyzing whether or not the packet is an encapsulated packet, a second step of decapsulating the encapsulated packet if the encapsulated packet is included, and decomposing the encapsulated packet into a plurality of packets by the decoupling, Of the unencapsulated packet and the decapsulated packet, this determination is the same as the third step of determining whether or not the wireless base station that includes the communication partner within the communication range includes the same packet. A fourth step of reading out packets of the same destination when a packet is included, and a fifth step of combining the read-out packets into one packet; If the packet indicates a different packet, the sixth step of setting the holding time while temporarily holding each packet, and measuring the passage of the set time, and holding immediately after the lapse of the set time A seventh step of reading out the received packet, an eighth step of performing pre-transmission processing on the packet read out in the fourth and seventh steps, and directing the pre-transmission-processed packet to the adjacent radio base station And a ninth step of transmitting.

  The wireless relay method of the present invention analyzes whether the packet is an encapsulated packet, releases the encapsulation according to the determination that the encapsulated packet is included, decomposes the packet into a plurality of packets, and is not encapsulated Among the packets and the decapsulated packets, it is determined whether or not the wireless base station that includes the communication partner within the communication range includes the same packet, and the corresponding packet is read according to the determination including the same packet, When encapsulating by integration and showing different packets, set each holding time while temporarily holding each packet, measure the elapsed time, and read and read the held packet immediately after the set time elapses The pre-transmission processing is performed on the encapsulated and non-encapsulated packets, and the pre-transmission packet is adjacent to the radio base station. By sending towards, to suppress over-header amount.

  Next, embodiments of a radio base station according to the present invention will be described in detail with reference to the accompanying drawings.

  In this embodiment, the radio base station of the present invention is applied to a multi-pop radio communication system 10. The illustration and description of parts not directly related to the present invention are omitted. In the following description, the signal is indicated by the reference number of the connecting line in which it appears.

  The multi-pop wireless communication system 10 of this embodiment is connected to a wired communication system 12 via a communication bus 14 as shown in FIG. Thereby, a wide communication network is constructed. In this communication network, voice communication, video communication, and the like are performed. The multi-pop wireless communication system 10 and the wired communication system 12 comply with the TCP (Transmission Control Protocol) / IP protocol and control to realize voice communication and moving image communication, as is apparent from the communication via the IP network 16. It has a function that operates with the protocol. Examples of the control protocol include ITU-T (International Telecommunication Union-Telecommunication) recommendation H.323 and SIP (Session Initiation Protocol). The IP network 16 is a communication network that constructs the Internet / intranet or the like.

  The multi-pop wireless communication system 10 uses a CSMA / CA scheme, and has a plurality of access points corresponding to base stations. The plurality of access points are referred to as wireless stations in this embodiment. Although not shown, each of the radio stations 18 to 26 is arranged so that the radio communication range overlaps with an adjacent radio station. Further, FIG. 2 of the present embodiment shows a state where the wireless terminal devices 28 and 30 which are mobile stations are accommodated in the communication area of the wireless station 18 by wireless connection. By arranging each of the radio stations 18 to 26 in this way, the radio stations 18 to 26 have a function of relaying a packet issued by one of the radio terminal devices 28 and 30 to an adjacent radio station. Yes. The multi-pop wireless communication system 10 can transfer a packet to a wireless station that does not directly receive radio waves. In particular, the radio station 26 has not only the relay function described above but also a gateway function for communicating with the wired communication system 12. The configuration of the radio station will be further described later.

  The wired communication system 12 includes routers 32 and 34, a server 36, and IP telephone terminals 38 and 40. Each of the routers 32 and 34 has an IP packet relay function and is connected to the IP network 16 at one end. The router 32 has the other end connected to the communication bus 14, and this connection enables communication connection with the multi-pop wireless communication system 10. The router 34 has a function of connecting to the IP telephone terminals 38 and 40 via the bus 42 and connecting the IP telephone terminals 38 and 40 to the IP network 16.

  The server 36 implements a control protocol for realizing voice communication and moving image communication on the IP network 16 to realize a voice application such as an IP phone.

  Next, the radio stations 18 to 26 will be briefly described. Since the radio stations 18 to 26 have the same configuration, the radio station 18 will be described as a representative. As shown in FIG. 1, the radio station 18 includes a diversity antenna 44, an amplifier 46, a radio transmission / reception unit 48, a radio MAC (Media Access Control) processing unit 50, a packet analysis unit 52, a decapsulation unit 54, a routing table 56, and a relay. A control unit 58, a counter 60, a capsule generation unit 62, and a wired processing unit 64 are included.

  Diversity antenna 44 has a plurality of antennas in preparation for realizing a function of switching to an antenna having a high reception power in accordance with a change in reception power or synthesizing radio waves received by a plurality of antennas. Each of the antennas is connected to the amplifier 46 and the wireless transmission / reception unit 48 to supply the received radio wave signal 66 to the wireless transmission / reception unit 48.

  The amplifier 46 is an amplifier having a function of increasing the signal strength of a transmission signal 68 as a transmission radio wave, for example.

  The wireless transmission / reception unit 48 has a function of performing transmission / reception processing on a wireless signal by performing mutual conversion between an electric signal and a wireless signal, modulation / demodulation, frequency conversion processing, and the like. When performing transmission processing, the wireless transmission / reception unit 48 has a function of modulating the transmission signal 70 supplied from the wireless MAC processing unit 50 and placing it on a carrier wave, and outputs the transmission signal 68 to the amplifier 46. When performing reception processing, the wireless transmission / reception unit 48 has a function of returning the received radio wave signal 66 to the baseband and demodulating it, and supplying the received signal 72 to the wireless MAC processing unit 50.

  The wireless MAC processing unit 50 has a function of processing assembly / disassembly of a wireless frame. The assembling / disassembling of the radio frame is performed in accordance with the media access control defined by the IEEE802.11 standard. The wireless MAC processing unit 50 supplies the disassembled wireless frame 74 to the bus 76, and supplies the wireless frame 74 to the packet analysis unit 52 via the bus 76. The wireless MAC processing unit 50 inputs transmission signals 78a and 78b used for assembling a wireless frame from the relay buffer 58 and the capsule generation unit 62 as the transmission signal 78.

  The packet analysis unit 52 has a function of analyzing the header part of the received packet, analyzes the packet supplied via the bus 76, determines whether the packet is encapsulated, and the packet is encapsulated. The packet 78 is output to the decapsulation unit 54 according to the determination that the packet is present. Further, the packet analysis unit 52 outputs a signal 80 including the unencapsulated packet and the reference search control signal to the routing table 56.

  The decapsulation unit 54 has a function of decapsulating the encapsulated packet when the received packet has already been encapsulated. The decapsulation unit 54 outputs the decapsulated packet 82 to the relay buffer 58.

  The routing table 56 stores route information or routing information to each wireless station created by exchanging control packets between wireless stations, and outputs a function that outputs unencapsulated packets through and outputs them according to control signals. The routing information to be stored is used as reference information, and an output signal 84 including the reference information and a packet not encapsulated is output to the relay buffer 58. The routing table 56 supplies the packet transmission interval and the like to the counter 60 as the buffering time information 86, and sets the buffering time.

  The relay control unit 58 includes a control function (not shown) and a relay buffer 59. The relay buffer 59 temporarily stores the supplied non-encapsulated packets 82 and 84. The relay control unit 58 includes a function of referring to each other as to whether or not there is the same destination among the stored packets, and a function of referring to the stored packet and the supplied reference information. The relay control unit 58 also has a function of determining whether to encapsulate a packet. Thereby, the relay control unit 58 separates the output 78a and the output 92. Further, the relay control unit 58 supplies a count start timing signal 88 to the counter 60 and receives a packet transmission timing signal 90 from the counter 60. The packet transmission timing signal 90 is also output at time-out. The relay control unit 58 outputs the packet 78a that is not encapsulated to the bus 76, and outputs the packet 92 to be encapsulated to the capsule generation unit 62.

  The counter 60 has a function of measuring the passage of a preset time, and sends a packet transmission timing signal 90 to the relay control unit 58. The counter 60 operates with a predetermined clock (not shown), and measures the passage of time. The set time will be described in the operation.

  The capsule generating unit 62 has a function of integrating and encapsulating a plurality of packets indicating the same destination into one packet 92, and outputs it as an encapsulated packet 78b. The packet 78b is supplied to the wireless MAC processing unit 50 via the bus 76.

  The wired processing unit 64 includes a wired MAC processing unit 94 and a wired transmission / reception unit 96. The wired MAC processing unit 94 has a function of processing assembly / disassembly of an Ethernet (registered trademark) frame that controls media access control defined by the IEEE 802.3 standard. The wired MAC processing unit 94 is supplied with a frame assembly packet 98 from only the relay buffer 58 via the bus 76. This is because when the destination is the wired communication system 12, it is not encapsulated in this embodiment. In addition, the wired MAC processing unit 94 supplies the packet 100 obtained by disassembling the frame to the bus 76, and supplies the packet to the packet analysis unit 52 via the bus 76. Further, the wired MAC processing unit 94 outputs the assembled packet 102 to the wired transmission / reception unit 96. The wired MAC processing unit 94 receives the reception signal 104 from the wired transmission / reception unit 96.

  The wired transmission / reception unit 96 has a gateway function for performing transmission of the IP network 16 and the packet 106 and reception of the packet 108, respectively. The wired transmission / reception unit 96 communicates with the wired MAC processing unit 94.

  However, it is obvious that the wired processing unit 64 needs to be provided only at least by the wireless station 26. If cost reduction is taken into consideration, the wired processing unit 64 is unnecessary in the wireless stations 18 to 24. Further, if the wired processing unit 64 is provided in the wireless station ignoring the cost, any wireless station can be used for connection to the wired communication system 12 and can be used with versatility.

  Next, the operation of the multi-pop wireless communication system 10 will be described. In the multi-pop wireless communication system 10, when a received packet is relayed to an adjacent wireless station, the packet addressed to the same wireless station is integrated into one packet by encapsulating it, thereby increasing one packet size, The use efficiency of the radio channel is increased and the throughput is improved.

  As a premise of this, the radio stations 18 to 26 exchange the information of the radio stations adjacent to each other using the control packet, and the route information to each radio station and each radio terminal device 28 and 30 is obtained in advance. Shall. For example, when the wireless station 26 receives a packet addressed to the wireless terminal device 30, since the wireless terminal device 30 is accommodated in the wireless station 18, the packet may be finally transferred to the wireless station 18, and the route It is assumed that it is known that the information or routing information to be transferred to the radio station 18 may be relayed to the radio station 20. Furthermore, at this time, it is assumed that a session by VoIP is started between the wireless terminal device 30 and the IP telephone terminal 40 and between the wireless terminal device 28 and the IP telephone terminal 38, respectively.

  First, the wireless station 26 receives packets addressed to the wireless terminal devices 28 and 30 from the IP telephone terminals 38 and 40 via the wired processing unit 64, and passes through the wireless transmission / reception unit 48 and the wireless MAC processing unit 50. Assume that packets addressed to the IP telephone terminals 38 and 40 are received from the wireless terminal devices 28 and 30 (step S10).

  The received packet is supplied to the packet analysis unit 52 via the bus 76. With this packet supply, the packet analysis unit 52 analyzes the header part of the packet (step S12). The analysis items here are: first, whether the packet is already encapsulated, second, whether the packet is a VoIP packet, and third, if the packet is a VoIP packet, the type of codec and the packet There are three types of information analysis such as transmission interval.

  Based on the result of the header analysis, it is determined whether the packet is unencapsulated (step S14). If the determination has already been encapsulated (NO), the process proceeds to the decapsulation process (to step S16). The packet may be supplied not only from the wired communication system 12, but also from the multi-pop wireless communication system 10, and the above-described encapsulation is performed in the wireless section. For this reason, in the wireless station 26, there is a possibility that a packet arriving from the wireless station 18 encapsulates packets from the wireless terminal devices 28 and 30 in the communication area. If the determination is not yet encapsulated (YES), the packet proceeds to refer to the routing table (to step S18).

  Decapsulation is released (step S16). The IP packets stored in the integrated packet are released in units of individual IP packets, output to the relay control unit 58, and stored in the relay buffer 59. After this cancellation, the process proceeds to output destination determination of the decomposed IP packet (to step S20). After releasing this packet, the supply destination of the decomposed packet is determined based on the address as the integrated packet (step S20). The address of the integrated packet is classified into a destination address included in the multi-pop wireless communication system 10 and a destination address other than this. When the destination address is the latter (YES), the operation procedure proceeds to a transmission process for each packet from the relay control unit 58 to the communication partner of the wired communication system 12 (to step S22). The wireless station 26 transmits each packet from the relay control unit 58 to the communication partner of the wired communication system 12 (step S22).

  On the other hand, when the originally received packet is not encapsulated, this packet is supplied to the relay buffer 59 in the relay control unit 58 together with the reference information via the routing table 56. Although not shown, the wireless station 26 checks the IP address of the transmission source and destination (transmission destination) included in the IP header. When the destination IP address does not indicate the IP address of the wireless station of the multi-pop wireless communication system 10, it is determined that the communication is to the wired communication system 12, and is output to the wired processing unit 64.

  Note that the routing table 56 refers to the unencapsulated packet and the value of the table at this stage, and sends the unencapsulated packet from the packet analysis unit 52 and the reference result to the relay control unit 58. You may make it output.

  Next, the unencapsulated packet and the reference information supplied by the relay control unit 58 are referred to (step S18). The unencapsulated packet here means not only the output from the packet analysis unit 52 but also the output from the packet release unit 54. The relay control unit 58 refers to each other whether or not the unencapsulated packets have the same destination (step S24). In this embodiment, an address indicating a destination is represented by a reference symbol of each device.

  Next, after these series of references, it is determined from the destination address whether or not a packet addressed to the same wireless station is held in the relay buffer 59 (step S26). If there is a packet addressed to the same wireless station (YES), the process proceeds to a process of reading the corresponding packet from the relay buffer 58 (to step S28). If there is no packet addressed to the same wireless station (NO), the process proceeds to temporary storage of a packet not addressed to the same wireless station (to step S30).

  Next, the corresponding packet is read from the relay buffer 59 of the relay control unit 58 (step S28). The relay control unit 58 sends out the packet having the same address to the capsule generation unit 62. The capsule generating unit 62 encapsulates the supplied packet (step S32).

  Here, as shown in FIG. 4, the packets 110 and 112 are already held so as to be supplied from the IP telephone terminal 38 to the wireless terminal device 28 and from the IP telephone terminal 40 to the wireless terminal device 30, respectively. And As a result of determining that the data in the header area 114 has the same route to the radio station 18 based on the two references described above, the capsule generator 62 collectively sends these packets 110 and 112 from the radio station 26 to the radio station 18. A header area 114 in the packet 116 indicating that is generated. The header area 114 has an IP header and a UDP (User Datagram Protocol) header. The capsule generation unit 62 places the packets 110 and 112 after the generated header 114. Encapsulation is a process of sending a plurality of packets that clearly follow the same route on the route.

  In this embodiment, a method of encapsulating IP packets with IP packets is applied. However, for example, a method of encapsulating data link layer frames with IP packets may be applied. In this case, in the encapsulated packet, Ethernet (registered trademark) frame information is added to each of the packets 110 and 112.

  In this way, the packet 116 encapsulated is subjected to wireless pre-transmission processing (step S34). In the pre-transmission processing, the wireless MAC processing unit 50 adds wireless frame overhead.

  Thereafter, the radio station 26 transmits a packet 116 (step S22). The packet 116 is transmitted to the wireless station 18 through the wireless transmission / reception unit 48 and the amplifier 46. At this time, in the routing table 56, since the relay destination to the radio station 18 is described as the radio station 20, the transmission destination of the packet, that is, the MAC address is the radio station 20. The radio station 20 that has received the encapsulated packet 116 relays the packet 116 to the radio station 18 that is the destination radio station. When the radio station 18 receives the encapsulated packet 116, the radio station 18 releases the encapsulation using the decapsulation unit 54, transmits the packets 110 and 112 to the radio terminal devices 28 and 30, and relays them.

  On the other hand, when there is no packet addressed to the same radio station in the relay buffer 59 (NO), the received packet not addressed to the same radio station is temporarily held in the relay buffer 58 (step S30). Thereafter, the buffering time is set (step S36). This time setting indicates a holding time when holding a packet not addressed to the same wireless station in the relay buffer 59. The value of the buffering time is set in the counter 60.

  The counter 60 determines whether or not the set time has elapsed (step S38). If the time has not elapsed (NO), the process proceeds to a new reception of the packet (to step S10). When the time has elapsed (YES), a timing signal 90 for transmitting a packet is output from the relay buffer 59. In this way, the buffering time and timing are controlled. In this timing control, it is assumed that there is no packet to be encapsulated in response to the timeout associated with the elapse of the buffering time, and the packet reading process is performed without encapsulating (to step S40). The value of the buffering time may be a fixed value. For example, in the case of a VoIP packet, the packet transmission interval obtained by the packet analysis unit 52 may be used. If the time to be set is set to a value larger than the packet transmission interval, the packet is received, and if a value less than or equal to the packet transmission interval is set, it is preferable to wait for the passage of time or perform a re-reference process. Specifically, when the packet transmission interval is 50 ms, the wireless station 26 can avoid buffering two or more received packets of the same session by setting the buffering time to be equal to or less than this value. .

  Packets not addressed to the same wireless station are read from the relay buffer 58 according to the buffering timing control (step S40). This packet is not encapsulated, and is subjected to pre-transmission processing (step S34) and transmission processing (step S22) by a normal procedure, and relayed to other radio stations.

  By operating in this way, packets addressed to a plurality of wireless terminals accommodated in the same wireless station can be integrated into one packet and transmitted. Thereby, it is possible to reduce the frequency of carrier sense and reduce the overhead amount of the wireless section, and improve the throughput of the multi-hop wireless communication section.

  Here, packet encapsulation is generally used to smoothly perform communication between layers having different original purposes.

  Next, another embodiment of the multi-pop wireless communication system 10 to which the wireless communication system of the present invention is applied will be briefly described. In the multi-pop wireless communication system 10 of this embodiment, as shown in FIG. 5, a wireless terminal device 118 is newly accommodated and added to the wireless station 20 together with the components shown in FIG. The difference is that a terminal 120 is provided.

  In the present embodiment, one of the radio stations 18 to 26 will be described, the same reference numerals will be given to common components, and the description will be omitted to avoid complicated description. This embodiment is different from the previous embodiment in that it has a function of returning the packet 122 encapsulated by the capsule generating unit 62 to the relay buffer 59 in the relay control unit 58.

  Next, the operation will be described. The operation in this embodiment is to increase the efficiency of use of the radio channel by integrating a plurality of packets into one packet by encapsulation as in the previous embodiment, and the target of encapsulation is addressed to the same radio station. It is characterized in that not only packets but also packets on the same route are targeted.

  As in the previous embodiment, the premise is that the wireless station 18 and 26 have been constructed in the routing table 56, the wireless terminal device 30 and the IP telephone terminal 40, the wireless terminal 28 and the IP telephone terminal 38, and Assume that a VoIP session is started between the wireless terminal device 118 and the IP telephone terminal 120, respectively.

  First, as shown in FIG. 7, it is assumed that the wireless station 26 receives a packet addressed to the wireless terminal device 30 from the IP telephone terminal 40 (step S10). Thereafter, the procedure is the same as in the previous embodiment up to the determination process (step S26) of whether or not a packet addressed to the same wireless station is in the relay buffer 58. If there is no packet addressed to the same wireless station (NO), the process proceeds to a process for determining whether or not a packet on the same route is in the relay buffer 58 (to step S42). If there is a packet addressed to the same radio station (YES), the process proceeds to reading of the packet (to step S44).

  The same route determination process (step S42) is a process for determining whether there is a radio station 20 positioned as a relay radio station of the radio station 26 and the radio station 18 in FIG. The route information that is the basis for this determination is already stored in the routing table 56 of each wireless station. The radio station 26 can make the determination by referring to the route information and the received packet. If there is no packet addressed to the same wireless station and there is no packet on the same route (NO), the process proceeds to buffering of the received packet not corresponding to these (to step S30). If there is no packet addressed to the same wireless station and there is a packet on the same path (YES), the process proceeds to reading of the packet (to step S44).

  The packet reading (step S44) is a process of reading the packet addressed to the same radio station and the packet located on the path addressed to the same radio station in the previous embodiment. The read packet is supplied to the capsule generating unit 62 and encapsulated (step S32). As shown in FIG. 8, the capsule generation unit 62 encapsulates the packet 116 addressed to the same radio station and the packet 124 on the same route, and adds a header area 114 to be transmitted from the radio station 26 to the nearest radio station 20. Then, an IP packet 126 addressed to the same wireless station is generated. When a packet addressed to the wireless terminal device 118 is received from the IP telephone terminal 120, this is held first because the wireless terminal device 118 is accommodated in the wireless station 20 on the route of the wireless station 18. This means that the packet is regarded as a packet on the same route as the encapsulated packet 116 addressed to the radio station 18.

  In this embodiment, the encapsulated packet 126 is not transmitted immediately, but is supplied to the relay control unit 58 until the set time of the buffering time elapses and is held in the relay buffer 59 again. Therefore, the capsule generating unit 62 outputs the encapsulated packet 126 to the relay buffer 58 via the signal line 122.

  Next, the relay buffer 59 buffers the supplied packet 126 (step S46). After this, the process proceeds to time lapse determination (go to step S38). The relay buffer 58 temporarily holds each of the encapsulated packet 126 and the unencapsulated packet until the time set time elapses.

  After the buffering time has elapsed, the relay control unit 58 reads the packet stored in the relay buffer 59 (step S40). After this reading, the read packet is subjected to pre-transmission processing (step S34) and transmission processing (step S22) and relayed to the other radio stations 20 and 18.

  By operating in this way, packets destined for wireless terminal devices accommodated in wireless stations on the same route can be integrated into one packet. Thereby, it is possible to reduce the frequency of carrier sense and reduce the overhead amount of the wireless section, and it is possible to further improve the throughput of the multi-hop wireless communication section.

  By configuring as described above, among the plurality of radio stations 18 to 26, each adjacent radio station overlaps the communicable range so that each radio station has a relay function with respect to the adjacent radio station. The packet analysis unit 52 determines the presence or absence of the encapsulated packet, individually disassembles the packet encapsulated by the packet release unit 52, and the routing information stored in the routing table 56 and the packet in the relay control unit 58 Based on the destination information of the packet, the presence or absence of packets addressed to the same radio station is searched and determined, and the packets detected by the capsule generator 62 are integrated into one packet in response to multiple detections of packets addressed to the same radio station. Thus, the amount of random waiting time is reduced by reducing the frequency of carrier sense while suppressing the amount of overheader. As a result, the throughput of the multi-hop wireless communication section can be improved.

  The relay control unit 58 includes a relay buffer 59 that temporarily stores individual packets, and the wireless station further measures the storage (holding) time of the packets stored in the relay buffer 59 by the counter 60, for example, By setting the time as the transmission interval, transmission for each session becomes possible.

  Among the wireless stations 18 to 26, at least the wireless station 26 connected to the wired communication system 12 can be provided with a wired processing unit 64 that communicates individual packets that have been disassembled, thereby realizing a wide range of communication.

  In addition, by providing the wireless stations 18 to 26 and constructing the multi-pop communication system 10, a network with high communication efficiency can be realized.

  Further, the wireless relay method analyzes whether or not the packet is an encapsulated packet, releases the encapsulation according to the determination that the encapsulated packet is included, decomposes the packet into a plurality of packets, and unencapsulated packets. Among the decapsulated packets, whether or not the wireless station addressed to the communication station within the communication range includes the same packet, the corresponding packet is read according to the determination including the same packet, and integrated When encapsulating and showing different packets, set each holding time while temporarily holding each packet, measure the elapsed time, and read the held packet immediately after the set time elapses. The pre-transmission processing is performed on the packets that are encapsulated and de-encapsulated, and the pre-transmission packets are sent to the adjacent FIG. 1 and FIG. By sending towards the station 20, to suppress the over-header amount, reducing the random wait time amount by reducing the frequency of the carrier sense, it is possible to improve the throughput of the multi-hop wireless communication section.

  The wireless relay method determines whether or not a packet addressed to a radio station includes a packet addressed to a wireless station if the packet indicates a different packet after determining whether or not the packet addressed to the wireless station includes the same packet. Proceeding to processing (step S42), in encapsulation, as shown in FIG. 8, a packet integrated to the same wireless station is generated, and a packet 124 addressed to a wireless station on the same route is added to this integrated packet 116. By generating a larger integrated packet 126, it is possible to reduce the frequency of carrier sense and reduce the overhead amount of the wireless section, and further improve the throughput of the multi-hop wireless communication section.

It is a block diagram which shows the schematic structure of the radio station used in the Example in the multipop radio | wireless communications system to which the radio base station of this invention is applied. It is a figure which shows the structure of the network constructed | assembled by the multi-pop radio | wireless communications system using the radio station of FIG. 1, and a wired communication system. 3 is a flowchart for explaining a relay operation in the radio station of FIG. 1. It is a figure explaining the relationship between encapsulation and each packet used in the relay operation of FIG. It is a figure which shows the structure of the network constructed | assembled by the multi-pop radio | wireless communications system as another Example to which the radio base station of this invention is applied, and a wired communication system. FIG. 6 is a block diagram of a schematic configuration shown as another example in the wireless station of FIG. 5. 7 is a flowchart for explaining a relay operation in the radio station of FIG. 6. FIG. 8 is a diagram for explaining the relationship between encapsulation and each packet used in the relay operation of FIG. 7.

Explanation of symbols

10 Multipop wireless communication system
12 Wired communication system
18-26 radio stations
28, 30 Wireless terminal equipment
52 Packet analyzer
54 Decapsulation part
56 Routing table
58 Relay control unit
59 Relay buffer
60 counter
62 Capsule generator

Claims (6)

A relay function in communication of packets by wirelessly communicating packets with wireless base stations adjacent to each other by arranging communication ranges of adjacent wireless base stations to overlap among wireless base stations in wireless communication In each of the radio base stations, the radio base station,
An analysis means for analyzing whether the received packet is an encapsulated packet including a plurality of packets;
Release means for decomposing the encapsulated packet into individual packets;
Route storage means for storing route information for relaying the wireless base station and sending the received packet to a communication partner;
Determining means for determining whether or not there are a plurality of packets addressed to the same base station based on the destination information and the path information included in each of the received packets;
A radio base station, comprising: an integration unit that integrates a single packet corresponding to the determination according to a determination result in which a plurality of packets transmitted to the same base station exist. The radio base station according to claim 1, wherein the determination unit includes a packet storage unit that temporarily stores individual packets,
The radio base station further includes a measurement unit that measures a lapse of time during which the packet storage unit stores the packet.   3. The radio base station according to claim 1, wherein the radio base station includes processing means for communicating the disassembled individual packets at least in the radio base station connected to the wired communication system. Radio base station.   4. The radio communication system according to claim 1, wherein a multi-pop communication system is constructed by providing a plurality of the radio base stations. In a relay method for wirelessly communicating and relaying packets with adjacent wireless base stations, the method includes:
A first step of analyzing whether a received packet is an encapsulated packet including a plurality of packets;
A second step of decapsulating the encapsulated packet and decapsulating the encapsulated packet into a plurality of packets when the encapsulated packet is included;
A third step of determining whether the unencapsulated packet and the decapsulated packet include the same packet addressed to a radio base station that includes a communication partner within a communication range;
A fourth step of reading the same destination packet if the determination includes the same packet;
A fifth step of integrating the read packets into one packet;
When the determination indicates a different packet, a sixth step of setting the holding time and measuring the passage of the set time while temporarily holding each packet;
A seventh step of reading the held packet immediately after the set time has elapsed;
An eighth step of performing pre-transmission processing on the packets read in the fourth and seventh steps;
And a ninth step of transmitting the preprocessed packet to an adjacent radio base station. 6. The method according to claim 5, wherein after the determination in the third step, the method indicates whether the packet addressed to the radio base station includes a radio station addressed on the same path when the determination indicates a different packet. Including a tenth step of determining
The fifth step is to generate an integrated packet addressed to the same radio base station, and generate a larger integrated packet by adding a packet addressed to the radio station on the same path to the integrated packet. A wireless relay method.

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