Hand-off method using edge nodes in mobile ad-hoc network

• US 20060092898A1
• Filed: 11/02/2005
• Published: 05/04/2006
• Est. Priority Date: 11/03/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Jae-hoon, Singh, Shubhranshu, Kim, Jung-ho, Choi, Young-gon, Roh, Yong-sung, Kang, Kyung-lim
• Granted Patent: US 7,535,883 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04W 36/1446 wherein at least one of the networks is unlicensed
• CPC Class Codes: H04W 40/28 for reactive routing
• CPC Class Codes: H04W 40/30 for proactive routing

Abstract

A hand-off method including detecting edge nodes located at edges of a mobile ad-hoc network (MANET); retransmitting, at the detected edge nodes, an Internet gateway advertisement message (IGAM) at a new period; and performing a hand-off of a mobile device moving from an infrastructure network to the MANET using the retransmitted IGAM.

Claims

1. A hand-off method comprising:

detecting edge nodes located at edges of a mobile ad-hoc network (MANET);

retransmitting, at the detected edge nodes, an Internet gateway advertisement message (IGAM) at a new period; and

performing a hand-off of a mobile device moving from an infrastructure network to the MANET using the retransmitted IGAM.

2. The hand-off method according to claim 1, wherein the new period is a random value ranging from approximately 0.03 seconds to 0.07 seconds according to a mobile Internet Protocol version 6 (IPv6).

3. The hand-off method according to claim 1, wherein the new period is proportional to a number of neighbor nodes having a same communication range as the edge nodes.

4. The hand-off method according to claim 1, wherein the new period is calculated in accordance with the following equation:

new period=initial period * the number of neighbor nodes * V;

wherein the neighbor nodes are located within a same communication range covered by the edge nodes, the initial period is adjustable according to the number of neighbor nodes in a range from approximately 3 to 16 seconds, and V is a random value more than 0 and less than 2.

5. The hand-off method according to claim 1, wherein the detecting the edge nodes comprises:

broadcasting the IGAM and an identifier (ID) indicating a number of times of sequentially broadcasting the IGAM from the Internet gateway to an intermediate node in the MANET; and

establishing, at the intermediate node receiving the IGAM, a reverse route to the Internet gateway and retransmitting the received IGAM to a one-hop node;

wherein the intermediate node is detected as one of the edge nodes in the MANET in response to the intermediate node not re-receiving a message transmitted from another intermediate node having a greater hop count than a hop count of the intermediate node.

6. The hand-off method according to claim 5, further comprising:

not processing, at the intermediate node, IGAMs received after a second IGAM, and transmitting a discard information message to previous nodes that transmit the IGAMs after the second IGAM in response to the intermediate node receiving a plurality of IGAMs having a same ID from the previous nodes located at a same distance from the Internet gateway; and

detecting the previous nodes that receive the discard information message as the edge nodes in the MANET.

7. The hand-off method according to claim 5, wherein the intermediate node does not process the IGAM received from the intermediate node having the greater hop count, and does not update a reverse route to the Internet gateway, in response to the intermediate node receiving an IGAM from a node having a smaller hop count than the intermediate node, and then receiving an IGAM having a same ID from another node having a greater hop count than the intermediate node.

8. The hand-off method according to claim 6, wherein the intermediate node updates a reverse route to the Internet gateway according to the IGAM received from the node having the smaller hop count in response to the intermediate node receiving an IGAM from a node having a greater hop count than the intermediate node, and then receiving an IGAM having a same ID from another node having a smaller hop count.

9. The hand-off method according to claim 5, wherein the intermediate node updates the reverse route to the Internet gateway in response to an IGAM having an increased ID being received.

10. The hand-off method according to claim 5, wherein the hop count is a distance from the Internet gateway to the intermediate node.

11. A hand-off method comprising:

adjusting a period of an Internet gateway advertisement message (IGAM); and

retransmitting, at edge nodes of a mobile ad-hoc network (MANET), the Internet gateway advertisement message (IGAM) with the adjusted period.

12. The hand-off method of claim 11, further comprising performing a hand-off of a mobile device moving into the MANET using the retransmitted IGAM.

13. The hand-off method of claim 11, wherein the adjusted period is proportional to a number of neighbor nodes having a same communication range as the edge nodes.

14. The hand-off method of claim 11, wherein the adjusted period of the IGAM is equal to an initial period of the IGAM multiplied by a number of neighbor nodes in a same communication range as the edge nodes and again multiplied by a random value between 0 and 2.

15. The hand-off method of claim 14, wherein the initial period is adjustable according to the number of neighbor nodes in a range from approximately 3 to 16 seconds.

16. The hand-off method of claim 11, further comprising detecting the edge nodes of the MANET.

17. The hand-off method of claim 16, wherein the detecting the edge nodes comprises:

broadcasting the IGAM and an identifier indicating a number of times the IGAM is sequentially broadcasted from the Internet gateway to an intermediate node in the MANET;

establishing a reverse route from the intermediate node to the Internet gateway and retransmitting the received IGAM from the intermediate node to a one-hop node;

wherein the intermediate node is detected as one of the edge nodes in response to the intermediate node not receiving a message from another intermediate node having a greater hop count.

18. A method of detecting edge nodes of a mobile ad-hoc network (MANET), the method comprising:

broadcasting an Internet gateway advertisement message (IGAM) and an identifier (ID) indicating a number of times the IGAM is sequentially broadcasted from the Internet gateway to an intermediate node in the MANET; and

establishing a reverse route from the intermediate node to the Internet gateway and retransmitting the received IGAM from the intermediate node to a one-hop node;

wherein the intermediate node is detected as one of the edge nodes in response to the intermediate node not receiving a message from another intermediate node having a greater hop count.

19. The method of claim 18, further comprising the intermediate node disregarding IGAMs received after a second IGAM in response to receiving a plurality of IGAMs having a same ID from previous nodes located at a same distance from the Internet gateway.

20. The method of claim 19, wherein the intermediate node transmits a discard information message to the previous nodes that transmit the IGAMs after the second IGAM.

21. The method of claim 20, wherein the previous nodes receiving the discard information become edge nodes in response to there being no more nodes located more hops from the Internet gateway than the respective previous nodes.