JP4837612B2 - Radio link selection control device, radio device and radio link selection method - Google Patents

Description

  The present invention relates to a radio link selection control device, a radio device, and a radio link selection method.

In recent years, a technique called cognitive radio communication in which one radio station performs communication using a plurality of radio communication media has been studied. Non-Patent Document 1 discloses mobile IP (Internet) when connecting to a plurality of wireless communication media (for example, a cellular system and a wireless local area network (wireless LAN) system) installed at different locations. A technique for performing seamless media switching by using (Protocol) is described. Non-Patent Document 2 describes wireless communication at the IP layer when a mobile router is mounted on an ITS (Intelligent Transport System) vehicle that connects to and communicates with a plurality of wireless communication media (for example, a cellular system and a wireless LAN system). A technique for switching media is described. Non-Patent Document 3 describes link aggregation in which a plurality of physical lines are aggregated and provided as one logical line.
Saito, et al., “Development of software for switching between different types of wireless communication media”, B-5-289, IEICE General Conference, 2003 Kashimura, et al. “Implementation of in-vehicle mobile router capable of switching communication media”, B-7-103, IEICE General Conference, 2003 IEEE802.3ad Standard (IEEE Computer Society LAN MAN Standards Committee) Aggregation of Multiple Link Segments, 2000.

  However, in cognitive wireless communication, it is possible to use wireless communication media fairly from among a plurality of wireless communication media, and to maintain fair use between wireless links in the same wireless communication media, thereby stabilizing communication quality. It has become a challenge.

  The present invention has been made in view of such circumstances, and its purpose is to use wireless communication media fairly among a plurality of wireless communication media and to use between wireless links in the same wireless communication media. An object of the present invention is to provide a radio link selection control device, a radio device, and a radio link selection method capable of maintaining fairness and stabilizing communication quality.

  In order to solve the above-described problems, a radio link selection control device according to the present invention monitors communication for each radio communication medium in the radio link selection control device when one radio station uses a plurality of radio communication media. From the monitoring result of the wireless communication media monitoring means, the monitoring result of the wireless communication media monitoring means, the multiplicity calculation means for calculating the multiplicity of the wireless station for each wireless communication medium, and the monitoring result of the wireless communication media monitoring means, For each wireless communication medium, a wireless link usage rate calculating means for calculating a wireless link usage rate excluding the usage of the own station, a multiplicity of the wireless station for each wireless communication medium calculated by the multiplicity calculating means, Based on the wireless link usage rate for each wireless communication medium calculated by the wireless link usage rate calculating means, for each wireless station of the communication counterpart, which wireless communication media A wireless link determining means for determining whether to use a link, wherein the wireless link determining means selects a wireless communication medium with a low degree of multiplicity as the highest priority, and a wireless link unused rate in the selected wireless communication medium Alternatively, the wireless link having the largest available communication capacity is selected.

  A wireless device according to the present invention is a wireless device that uses a plurality of wireless communication media, and includes the above-described wireless link selection control device.

  In the radio apparatus according to the present invention, the radio communication medium provided in the upper layer of the data link layer in the radio communication medium and used in units of IP packets or data link layer packets is selected according to the determination of the radio link selection control apparatus. Data link layer packet switch means is provided.

  The radio link selection method according to the present invention is a radio link selection method when one radio station uses a plurality of radio communication media, the process of monitoring communication for each radio communication medium, and from the monitoring result, The process of calculating the radio station multiplicity for each radio communication medium, the process of calculating the radio link usage rate excluding the use of the own station for each radio communication medium from the monitoring result, and the calculated Based on the multiplicity of radio stations for each radio communication medium and the calculated radio link usage rate for each radio communication medium, the radio link of which radio communication medium is used for each radio station of the communication partner A radio link determination process, wherein the radio link determination process selects a radio communication medium with a low degree of multiplicity as the highest priority, and an unused radio link is selected in the selected radio communication medium. Communication capacity rate or vacant and selects the maximum of the radio link.

  According to the present invention, among a plurality of wireless communication media, a stable communication quality is obtained while ensuring fair use among wireless stations, and an appropriate wireless communication medium is used for fair use of the wireless communication media. It becomes possible to select and use.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a wireless station (wireless device) 1 according to an embodiment of the present invention. In FIG. 1, the wireless station 1 includes a plurality of wireless communication media wireless modules 11, a packet switch 12, an IP (Internet Protocol) layer unit 13, and a control unit 14.

  Each wireless module 11 has functions of a PHY layer and a data link layer corresponding to each wireless communication medium. Examples of functions of the data link layer include MAC (Medium Access Control) and LLC (Logical Link Control). The wireless module 11 transmits and receives data link layer packets to and from the packet switch 12. The wireless module 11 performs wireless transmission and wireless reception of data link layer packets. In addition, the wireless module 11 may be provided with the same wireless communication media, but with different frequency channels.

  The packet switch 12 has a data link layer packet switching function. The packet switch 12 has a buffer provided corresponding to each wireless module 11 and performs buffering of data link layer packets transmitted to and received from the wireless module 11. The packet switch 12 has a conversion function for performing mutual conversion between the data link layer packet and the IP packet. The packet switch 12 transmits and receives IP packets to and from the IP layer unit 13.

  The control unit 14 controls the packet switch 12. Specifically, the wireless link of which wireless module 11 is to be used is determined for each IP packet, and the packet switch 12 is instructed.

  The packet switch 12 converts the IP packet received from the IP layer unit 13 into a data link layer packet by the conversion function, and outputs the data link layer packet to the wireless module 11 designated by the control unit 14. Further, the packet switch 12 converts the data link layer packet received from each wireless module 11 into an IP packet by the conversion function, and outputs the IP packet to the IP layer unit 13.

  At the time of transmission, the wireless module 11 converts the data link layer packet received from the packet switch 12 into a unique format of its own wireless communication medium and wirelessly transmits it. Further, at the time of reception, the data link layer packet of the specific format received wirelessly is converted into a data link layer packet of the common format and output to the packet switch 12.

  The IP layer unit 13 notifies the control unit 14 of information on input / output IP packets. The IP packet information to be notified includes, for example, address information (destination IP address, transmission source IP address, TCP (Transmission Control Protocol) port address, etc.), connection type (single connection, multiple connections), communication quality for IP flow. Request (transmission speed, QoS, etc.).

  The control unit 14 identifies an IP flow based on the address information notified from the IP layer unit 13 and determines a communication partner radio station. Then, the wireless module 11 of the wireless communication medium that can be used with the wireless station of the communication partner is selected for each IP packet from which wireless module 11 of the wireless communication medium is used. The selection result is instructed to the packet switch 12.

  FIG. 2 is a conceptual diagram illustrating an example of cognitive radio communication. In FIG. 2, each wireless station 1 (S1, D1, D2, D3) includes a wireless module 11 of three types of wireless communication media, and corresponds to each wireless communication medium. As examples of the three types of wireless communication media, in this embodiment, the IEEE (Institute of Electrical and Electronic Engineers) wireless access standard “IEEE802.16e” and the wireless LAN standard “IEEE802.11g” The description will be given with reference to “IEEE802.11j”. The wireless link 101 in FIG. 2 is an IEEE802.16e wireless link, the wireless link 102 is an IEEE802.11g wireless link, and the wireless link 103 is an IEEE802.11j wireless link.

  The wireless stations 1 (S1, D1) in FIG. 2 are connected by three wireless links 101, 102, 103. The wireless stations 1 (S1, D2) are connected by two wireless links 101 and 102. The radio stations 1 (S1, D3) are connected by one radio link 101.

FIG. 3 is a block diagram showing a configuration of the control unit 14 shown in FIG. FIG. 3 shows a characteristic part according to the present invention in the configuration of the control unit 14.
In FIG. 3, a wireless communication media monitoring unit 21 monitors communication for each wireless module of each wireless communication media. The multiplicity table generation unit 22 calculates the multiplicity for each wireless module from the monitoring result of the wireless communication media monitoring unit 21. The calculation result of the multiplicity is stored in the multiplicity table 23. The wireless link usage rate measuring unit 24 measures the usage rate of each wireless communication medium for each wireless link from the monitoring result of the wireless communication media monitoring unit 21. The radio link determination unit 25 determines which radio communication medium is used based on the usage rate of each radio link measured by the radio link usage rate measurement unit 24 and the multiplicity table 23.

  The wireless communication media monitoring unit 21 records which wireless station is connected to each wireless module 11 (wireless link connection information). At this time, it may be recorded whether or not the radio station connected to the radio link is in an active state. Further, the wireless communication media monitoring unit 21 records the actual usage time of the wireless link for each predetermined period for each wireless module 11. Here, when a plurality of wireless links are established for one wireless module, the actual usage time is recorded for each wireless link. The actual use time of the radio link refers to the time when the radio link is actually used for packet transmission. However, the time related to the packet related to the communication of the own station is excluded and recorded. Packets related to the communication of the local station include a communication packet and a control packet related to the communication packet. For example, in the IEEE802.11 related standard, a DATA packet as a communication packet is delivered by a series of procedures using four types of packets (RTS, CTS, DATA, ACK). Packets (RTS, CTS, ACK) other than DATA packets are control packets for DATA packet delivery. These four types of packets (RTS, CTS, DATA, ACK) related to the communication of the local station are excluded from the target of the actual use time of the radio link.

The multiplicity table generator 22 generates the multiplicity table 23 based on the radio link connection information recorded by the radio communication media monitoring unit 21. FIG. 4 is a flowchart of multiplicity table generation processing according to this embodiment. Note that a node refers to a radio station.
In FIG. 4, in step S <b> 1, the multiplicity table generation unit 22 creates a multiplicity table 23 related to adjacent nodes and wireless modules. At this time, the multiplicity table 23 is empty. The multiplicity table generation unit 22 detects a radio link connection destination radio station in the radio link connection information as an adjacent node. Alternatively, only the radio station in the active state of the radio link connection destination in the radio link connection information may be detected as an adjacent node.

  FIG. 5 shows an empty multiplicity table 23 corresponding to the example of FIG. In this example, there are three nodes as adjacent nodes, that is, wireless station 1 (node D1), wireless station 1 (node D2), and wireless station 1 (node D3) in FIG. The radio station 1 (node S1) is its own station. Each of the nodes S1, D1 to D3 has a wireless module of IEEE802.16e, IEEE802.11g, and IEEE802.11j.

  In step S2, the multiplicity table generation unit 22 checks whether there is a change in the number of adjacent nodes based on the radio link connection information. As a result, when there is a change, the multiplicity table 23 is updated according to the change content (step S3). On the other hand, if there is no change in the number of adjacent nodes, the process proceeds to step S4.

  In step S <b> 4, the multiplicity table generation unit 22 calculates the multiplicity of each wireless module based on the wireless link connection information, and writes the calculation result in the multiplicity table 23. The multiplicity of a certain wireless module is the total number of adjacent nodes having a wireless link connection with the wireless module. In the multiplicity table 23, the multiplicity of the radio module is written in the column of all adjacent nodes with radio link connection for one radio module.

  FIG. 6 shows a multiplicity table 23 corresponding to the example of FIG. With regard to the IEEE 802.16e wireless module, a wireless link 101 is connected between three nodes of the wireless station 1 (node D1), the wireless station 1 (node D2), and the wireless station 1 (node D3). Accordingly, in the multiplicity table 23, multiplicity “3” is written in the fields of the IEEE802.16e wireless module and each of the nodes D1, D2, and D3. Regarding the IEEE802.11g wireless module, a wireless link 102 is connected between two nodes of the wireless station 1 (node D1) and the wireless station 1 (node D2). Therefore, in the multiplicity table 23, multiplicity “2” is written in the fields of the IEEE802.11g wireless module and the nodes D1 and D2. Regarding the wireless module of IEEE802.11j, the wireless link 103 is connected between one node of only the wireless station 1 (node D1). Therefore, in the multiplicity table 23, multiplicity “1” is written in the field of the wireless module of IEEE802.11j and the node D1.

  When step S4 ends, the process returns to step S2 to check whether there is a change in the number of adjacent nodes.

Returning to FIG.
The wireless link usage rate measurement unit 24 calculates the usage rate of each wireless module for each wireless link based on the actual usage time of the wireless link for each fixed period recorded by the wireless communication media monitoring unit 21. The usage rate of the radio link is the actual usage time per unit time. Note that the usage rate of the wireless link does not include the usage of the own station.

  The radio link determination unit 25 determines which radio communication medium is used based on the usage rate of each radio link measured by the radio link usage rate measurement unit 24 and the multiplicity table 23.

Here, the radio link determination process performed by the radio link determination unit 25 will be described with reference to FIG. FIG. 7 is a flowchart of the radio link determination process according to the present embodiment.
In FIG. 7, in step S <b> 11, the wireless module (interface) having the minimum multiplicity is selected from the multiplicity table 23 for the target node to be a communication partner. In the example of FIG. 6, IEEE802.11j is selected.

  Next, in step S12, for the selected radio module, the unused rate or free throughput (communication capacity) of each radio link is calculated from the usage rate of each radio link. Then, the unused radio link rate or the free throughput is equal to or greater than the threshold value, and the maximum radio link (CH: channel) is selected. At this time, if the corresponding radio link exists, the process proceeds to step S13, and the selected radio link is assigned to the target node. On the other hand, if there is no radio link whose radio link unused rate or empty throughput is equal to or greater than the threshold, the process proceeds to step S14.

  In step S14, the wireless module having the next lowest multiplicity is selected from the multiplicity table 23. In the example of FIG. 6, IEEE802.11g is selected. At this time, if the corresponding wireless module exists, the process returns to step S12. On the other hand, if all the wireless modules in the multiplicity table 23 have already been selected, the process proceeds to step S15.

  In step S15, if there are free wireless links in order from the wireless module with the least multiplicity in the multiplicity table 23, the wireless link with the highest unused radio link rate or available throughput is determined regardless of the threshold. select. In step S13, the selected radio link is assigned to the target node.

The radio link assigned to the target node is determined by the above-described radio link determination process.
The control unit 14 determines the wireless module 11 to be used in units of IP packets according to the content determined by the wireless link determination unit 25 (which wireless module and wireless link are used with the communication partner wireless station). select. Then, the selection result is instructed to the packet switch 12.

  As described above, according to the present embodiment, wireless communication media can be used fairly by using wireless modules with low multiplicity with the highest priority. Further, since the wireless link having the highest unused link capacity or the empty communication capacity is used in the selected wireless module, the low-load wireless link is preferentially used. It is possible to maintain the fairness of use between links and stabilize communication quality.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, the control unit 14 may select a wireless communication medium to be used in units of data link layer packets and instruct the packet switch 12.

It is a block diagram which shows the structure of the radio station (radio | wireless apparatus) 1 which concerns on one Embodiment of this invention. It is a conceptual diagram which shows the example of cognitive radio | wireless communication. It is a block diagram which shows the structure of the control part 14 shown in FIG. It is a flowchart of the multiplicity table production | generation process which concerns on one Embodiment of this invention. 4 is a configuration example of a multiplicity table 23. 4 is a configuration example of a multiplicity table 23. It is a flowchart of the radio link determination process which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wireless station (radio | wireless apparatus), 11 ... Wireless module, 12 ... Packet switch, 13 ... IP layer part, 14 ... Control part, 21 ... Wireless communication media monitoring part, 22 ... Multiplicity table production | generation part, 23 ... Multiplicity Table 24: Radio link usage rate measuring unit 25 ... Radio link determining unit 101-103 ... Radio link

Claims (4)

In a radio link selection control device when one radio station uses a plurality of radio communication media,
Wireless communication medium monitoring means for monitoring communication for each wireless communication medium;
From the monitoring result of the wireless communication media monitoring means, multiplicity calculation means for calculating the multiplicity of the radio station for each wireless communication medium,
From the monitoring result of the wireless communication media monitoring means, for each wireless communication medium, a wireless link usage rate calculating means for calculating a wireless link usage rate excluding the portion used by the own station;
Based on the multiplicity of the radio station for each radio communication medium calculated by the multiplicity calculation means and the radio link usage rate for each radio communication medium calculated by the radio link usage rate calculation means, Radio link determination means for determining which radio communication medium radio link is used for each station,
The radio link determination means selects a radio communication medium with a low degree of multiplicity as the highest priority, and selects a radio link having a maximum unused radio link rate or a free communication capacity in the selected radio communication medium.
A radio link selection control device. In a wireless device using multiple wireless communication media,
A radio apparatus comprising the radio link selection control apparatus according to claim 1.   Data link layer packet switch means is provided above the data link layer in the wireless communication medium and selects a wireless communication medium to be used in units of IP packets or data link layer packets according to the determination of the wireless link selection control device. The wireless device according to claim 2. A radio link selection method when one radio station uses a plurality of radio communication media,
A process of monitoring communication for each wireless communication medium;
From the monitoring result, for each wireless communication medium, calculating the multiplicity of the wireless station,
From the monitoring result, for each wireless communication medium, a process of calculating the wireless link usage rate excluding the usage of the own station;
Based on the calculated multiplicity of radio stations for each radio communication medium and the calculated radio link usage rate for each radio communication medium, the radio link of which radio communication medium is determined for each radio station of the communication partner. Radio link determination process for determining whether to use,
In the wireless link determination process, a wireless communication medium with a low degree of multiplicity is selected with the highest priority, and a wireless link having a maximum unused link rate or free communication capacity is selected in the selected wireless communication medium.
A radio link selection method.

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