Radio node apparatus, multi-hop radio system, and multi-hop radio system constructing method

• US 20060040705A1
• Filed: 08/04/2005
• Published: 02/23/2006
• Est. Priority Date: 08/06/2004
• Status: Active Grant

• Current Assignee: National Institute of Information and Communications Technology, Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Nat'L Institute of Information and Communications Technology Incorporated Administration Agency, Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kawakami, Tetsuya, Fujise, Masayuki, Suzuki, Yoshihiro
• Granted Patent: US 7,885,601 B2
• Time in Patent Office: Days
• US Class Current: 455/561
• CPC Class Codes: H04L 45/122 by minimising distances, e.g. by selecting a route with minimum of number of hops
• CPC Class Codes: H04L 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 45/488 using root node determination
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 8/22 Processing or transfer of terminal data, e.g. status or physical capabilities
• CPC Class Codes: H04W 8/24 Transfer of terminal data
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

The present invention provides a radio node apparatus, a multi-hop radio system and a multi-hop radio system constructing method, capable of constructing a tree type multi-hop radio system in which mutual radio nodes determine a radio node which becomes a root node of a tree in an autonomous manner and the root node is set as a root in an autonomous manner. The radio node apparatus includes a storage unit for storing state information, used for constructing a multi-hop radio system, including information for specifying a root radio node apparatus positioned at a summit of the multi-hop radio system, with the radio node apparatus has a connection, and the number of hops from the root ratio node apparatus, a collection unit for collecting state information transmitted from surrounding radio node apparatus, and a selection unit for selecting a host connection-accepting radio node apparatus on the basis of the information for specifying the root radio node apparatus and the number of hops included in the collected state information.

Claims

1. A radio node apparatus for use in a tree-structured multi-hop radio system including a plurality of radio node apparatus, at least a portion of which is used as a repeater for carrying out multi-hop communication at layer 2, comprising:

a storage unit for storing state information, used for constructing said multi-hop radio system, including information for specifying a root radio node apparatus positioned at a summit of said multi-hop radio system, with said radio node apparatus has a connection, and the number of hops from said root ratio node apparatus;

a collection unit for collecting state information transmitted from, of said plurality of radio node apparatus, surrounding radio node apparatus around said radio node apparatus; and

a selection unit for selecting a host connection-accepting radio node apparatus on the basis of the information for specifying said root radio node apparatus and the number of hops included in the collected state information.

2. The radio node apparatus according to claim 1, wherein said selection unit selects radio node apparatus as a candidate for said host connection-accepting radio node apparatus, on the basis of the information for specifying said root radio node apparatus and sets, of the selected radio node apparatus, a radio node apparatus with the smallest number of hops as the candidate for said host connection-accepting radio node apparatus and makes a comparison between the root radio node apparatus specifying information, the number of hops in the candidate host connection-accepting radio node apparatus, set as the candidate, and the root radio node apparatus specifying information, the number of hops held in its own storage unit so as to, when a result of the comparison exceeds a predetermined comparison reference, select the candidate host connection-accepting radio node apparatus as said host connection-accepting radio node apparatus.

3. The radio node apparatus according to claim 1, further comprising a change unit for, when said selection unit selects said host connection-accepting radio node apparatus, rewriting, of the root radio node apparatus specifying information and the number of hops stored in said storage unit, the root radio node apparatus specifying information as the root radio node apparatus specifying information held in said host connection-accepting radio node apparatus and rewriting a value of the number of hops from said root radio node apparatus as a value obtained by adding 1 to the number of hops in said host connection-accepting radio node apparatus.

4. The radio node apparatus according to claim 1, wherein said state information includes a group priority indicative of a connection priority of a group, with which said radio node apparatus has a connection, and said selection unit checks said group priority with first priority to select the radio node apparatus with a higher group priority as said host connection-accepting radio node apparatus.

5. The radio node apparatus according to claim 4, further comprising a change unit for, when said selection unit selects said host connection-accepting radio node apparatus, rewriting, of the group priority, the root radio node apparatus specifying information and the number of hops, the group priority and the root radio node apparatus specifying information as the group priority and the root radio node apparatus specifying information held in said host connection-accepting radio node apparatus, and rewriting a value of the number of hops from said root radio node apparatus as a value obtained by adding 1 to the number of hops in said host connection-accepting radio node apparatus.

6. A tree-structured multi-hop radio system including a plurality of radio node apparatus, at least a portion of which is used as a repeater for carrying out multi-hop communication at layer 2, wherein each of said radio node apparatus stores, in a predetermined storage region, state information, used for constructing said multi-hop radio system, including information for specifying a root radio node apparatus positioned at a summit of said multi-hop radio system, with which it has a connection, and the number of hops from said root ratio node apparatus, and collects state information transmitted from surrounding radio node apparatus around it, and selects a host connection-accepting radio node apparatus on the basis of the information for specifying said root radio node apparatus and the number of hops included in the collected state information.

7. The multi-hop radio system according to claim 6, wherein said radio node apparatus selects radio node apparatus as a candidate for said host connection-accepting radio node apparatus on the basis of the information for specifying the root radio node apparatus and sets, of the selected radio node apparatus, the radio node apparatus with the smallest number of hops as the candidate for the host connection-accepting radio node apparatus and makes a comparison between the root radio node apparatus specifying information, the number of hops in the candidate host connection-accepting radio node apparatus, set as the candidate, and the root radio node apparatus specifying information, the number of hops held in its own storage region so as to, when a result of the comparison exceeds a predetermined comparison reference, select the candidate host connection-accepting radio node apparatus as said host connection-accepting radio node apparatus.

8. The multi-hop radio system according to claim 6, wherein, when said radio node apparatus selects said host connection-accepting radio node apparatus, said radio node apparatus rewrites, of the root radio node apparatus specifying information and the number of hops stored in said storage region, the root radio node apparatus specifying information as the root radio node apparatus specifying information held in said host connection-accepting radio node apparatus and rewriting a value of the number of hops from said root radio node apparatus as a value obtained by adding 1 to the number of hops in said host connection-accepting radio node apparatus.

9. The multi-hop radio system according to claim 6, wherein said state information includes a group priority indicative of a connection priority of a group, with which said radio node apparatus has a connection, and said radio node apparatus checks said group priority with first priority to select the radio node apparatus with a higher group priority as said host connection-accepting radio node apparatus.

10. The multi-hop radio system according to claim 9, wherein, when said radio node apparatus selects said host connection-accepting radio node apparatus, said radio node apparatus rewrites, of the group priority, the root radio node apparatus specifying information and the number of hops stored in said storage region, the group priority and the root radio node apparatus specifying information as the group priority and the root radio node apparatus specifying information in said host connection-accepting radio node apparatus, and rewrites a value of the number of hops from said root radio node apparatus as a value obtained by adding 1 to the number of hops held in said host connection-accepting radio node apparatus.

11. A method of constructing a tree-structured multi-hop radio system including a plurality of radio node apparatus, at least a portion of which is used as a repeater for carrying out multi-hop communication at layer 2, comprising:

a step in which, for selecting a host connection-accepting radio node, an arbitrary radio node apparatus of said plurality of radio node apparatus broadcasts a state information acquiring request to said plurality of radio node apparatus, other than said arbitrary radio node apparatus, each of which has state information including the total number of radio node apparatus connected to a tree-structured group with which each of the plurality of radio node apparatus has a connection, the number of hops from a root node positioned at a summit of said tree-structured group, identification information on said root node and its own identification information;

a step in which said arbitrary radio node apparatus of said plurality of radio node apparatus receives said state information from said plurality of radio node apparatus other than said arbitrary radio node apparatus; and

a step in which said arbitrary radio node apparatus of said plurality of radio node apparatus makes a comparison between the total number of radio node apparatus included in the received state information and the total number of radio node apparatus included in its own state information to select the radio node apparatus having said state information including the total number of radio node apparatus larger than the total number of radio node apparatus included in its own state information for selecting and connecting, of the selected radio node apparatus, the radio node apparatus having the smallest number of hops included in said state information as said host connection-accepting radio node apparatus.

12. The method according to claim 11, wherein said state information acquiring request is broadcasted only when said arbitrary radio node apparatus of said plurality of radio node apparatus is a root node of a group.

13. The method according to claim 11, further comprising a step in which said radio node apparatus connected as said host connection-accepting radio node apparatus receives said state information transmitted from said radio node apparatus connected thereto and holds the total number of radio node apparatus, included in the received state information, for each of said radio node apparatus connected thereto.

14. The method according to claim 11, further comprising a step in which said radio node apparatus connected as said host connection-accepting radio node apparatus outputs, to radio node apparatus in a group with which it has a connection, an after-connection state change notification including at least identification information on said arbitrary radio node apparatus of said plurality of radio node apparatus connected thereto and the total number of radio node apparatus included in said state information transmitted from the radio node apparatus connected thereto.

15. The method according to claim 11, further comprising a step in which said arbitrary radio node apparatus of said plurality of radio node apparatus which selects said host connection-accepting radio node apparatus and makes connection therewith receives said state information transmitted from said host connection-accepting radio node apparatus and, on the basis of the received state information, outputs, to a radio node apparatus connected as a subordinate thereto, an after-connection connection change notification including identification information on a root node after connection, its own identification information, the total number of radio node apparatus included in the received state information and a value obtained by adding 1 to the number of hops included in the received state information.

16. The method according to claim 11, further comprising a step in which, when said arbitrary radio node apparatus of said plurality of radio node apparatus which selects said host connection-accepting radio node apparatus and makes connection therewith is disconnected from said host connection-accepting radio node apparatus, said host connection-accepting radio node apparatus outputs, to the radio node apparatus in a group with which it has a connection, an after-disconnection state change notification including at least identification information on said arbitrary radio node apparatus of said plurality of radio node apparatus disconnected therefrom and the number of radio node apparatus connected as a subordinate to said arbitrary radio node apparatus of said plurality of radio node apparatus disconnected therefrom.

17. The method according to claim 11, further comprising a step in which, when said arbitrary radio node apparatus of said plurality of radio node apparatus which selects said host connection-accepting radio node apparatus and makes connection therewith is disconnected from said host connection-accepting radio node apparatus, said radio node apparatus disconnected from said host connection-accepting radio node apparatus outputs, to the radio node apparatus connected thereto as a subordinate, an after-disconnection connection change notification including its own identification information, identification information of a root node after the disconnection, a value obtained by subtracting the number of radio node apparatus connected thereto as a subordinate from the total number of radio node apparatus included in the state information before the disconnection, and a value “

1”

indicative of the number of hops.

18. The method according to claim 17, wherein, after the disconnection, said radio node apparatus disconnected holds the identification information on said root node before the disconnection and, in selecting a new host connection-accepting radio node apparatus, makes a comparison between the held identification information on said root node before the disconnection and the identification information on said root node held in the radio node apparatus which is a candidate for said host connection-accepting radio node apparatus and, when they coincide with each other, and makes a connection with the radio node apparatus which is the candidate for said host connection-accepting radio node apparatus on a preferential basis.

19. The method according to claim 16, further comprising a step in which said radio node apparatus disconnected therefrom operates as a root node of a new group.

20. A radio node apparatus for use in a tree-structured multi-hop radio system including a plurality of radio node apparatus, at least a portion of which is used as a repeater for carrying out multi-hop communication at layer 2, said radio node apparatus comprising:

a transmission unit for broadcasting a state information acquiring request, used for section of a host connection-accepting radio node apparatus, to said plurality of radio node apparatus, other than said radio node apparatus, each of which has state information including the total number of radio node apparatus connected to a tree-structured group with which each of said plurality of radio node apparatus has a connection, the number of hops from a root node positioned at a summit of said tree-structured group, identification information on said root node and its own identification information;

a reception unit for receiving the state information from said plurality of radio node apparatus other than it; and

a control unit for making a comparison between the total number of radio node apparatus included in the received state information and the total number of radio node apparatus included in its own state information to select the radio node apparatus having the state information including the total number of the radio node apparatus larger than the total number of radio node apparatus included in its own state information and further to select and connect, of the selected radio node apparatus, the radio node apparatus having the smallest number of hops included in the state information as said host connection-accepting radio node apparatus.

21. The radio node apparatus according to claim 20, wherein, only when said radio node apparatus is a root node of said group, said transmission unit broadcasts said state information acquiring request.

22. The radio node apparatus according to claim 20, wherein, in a case in which a connection is made as said host connection-accepting radio node apparatus, said reception unit receives said state information transmitted from said radio node apparatus connected thereto, and said control unit holds the total number of radio node apparatus included in the received state information for each of the radio node apparatus connected thereto.

23. The radio node apparatus according to claim 20, wherein, in a case in which a connection is made as said host connection-accepting radio node apparatus, said control unit outputs, to the radio node apparatus in a group with which it has a connection, an after-connection state change notification including at least identification information on the radio node apparatus connected thereto and the total number of radio node apparatus included in said state information transmitted from said radio node apparatus connected thereto.

24. The radio node apparatus according to claim 20, wherein, when making a selection as said host connection-accepting radio node apparatus and making a connection therewith, said reception unit receives said state information transmitted from said host connection-accepting radio node apparatus and, on the basis of the received state information, said control unit outputs, to the radio node apparatus connected thereto as a subordinate, an after-connection connection change notification including identification information on said root node after the connection, its own identification information, the total number of radio node apparatus included in the received state information and a value obtained by adding 1 to the number of hops included in the received state information.

25. The radio node apparatus according to claim 20, wherein, in a case in which a disconnection takes place from the radio node apparatus which makes a selection as said host connection-accepting radio node apparatus and makes a connection therewith, said control unit outputs, to the radio node apparatus in the group with which it has a connection, an after-disconnection state change notification including at least identification information on the radio node apparatus which has made the connection and disconnection and the number of radio node apparatus connected as a subordinate to the radio node apparatus which has made the connection and disconnection.

26. The radio node apparatus according to claim 20, wherein, in a case in which the radio node apparatus which has made a selection as said host connection-accepting radio node apparatus and a connection therewith makes a disconnection from said host connection-accepting radio node apparatus, said control unit outputs, to the radio node apparatus connected as its own subordinate, an after-disconnection connection change notification including the identification information on this radio node apparatus which has made the disconnection, the identification information on said root node before the disconnection, a value obtained by subtracting the number of radio node apparatus connected as its own subordinate from the total number of radio node apparatus included in the state information before the disconnection and value “

1”

indicative of the number of hops.

27. The radio node apparatus according to claim 26, wherein, in a case in which the radio node apparatus which has made a selection as said host connection-accepting radio node apparatus and a connection therewith is disconnected from said host connection-accepting radio node apparatus, said control unit holds, after the disconnection, identification information on said root node before the disconnection in a predetermined storage region and, in selecting a new host connection-accepting radio node apparatus, makes a comparison between the held identification information on said root node before the disconnection and the identification information on said root node held in the radio node apparatus which is a candidate for the host connection-accepting radio node apparatus and, if they coincide with each other, makes a connection with the radio node apparatus which is the candidate for the host connection-accepting radio node apparatus on a preferential basis.

28. The radio node apparatus according to claim 25, wherein, in a case in which the radio node apparatus which has made the selection as said host connection-accepting radio node apparatus and the connection therewith is disconnected from said host connection-accepting radio node apparatus, said control unit makes this radio node apparatus, disconnected, operate as a root node of a new group.