Process for Routing Data Packets in a Mobile Node Network and Associated Terminal

• US 20090274093A1
• Filed: 05/15/2007
• Published: 11/05/2009
• Est. Priority Date: 05/24/2006
• Status: Active Grant

• Current Assignee: Orange S.A.
• Original Assignee: Orange S.A.
• Inventors: Meraihi, Rabah, Senouci, Sidi-Mohammed, Jerbi, Moez
• Granted Patent: US 8,270,347 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 45/06 Deflection routing, e.g. hot-potato routing
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04W 40/20 based on geographic position or location
• CPC Class Codes: H04W 40/38 adapting due to varying relative distances between nodes
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A method of routing data packets (P) between a source node (S) and a target node (C) in an ad hoc network comprising mobile nodes (1-14) that can be located and moving on traffic routes (L1, L2, L3, C1, C2, C3) of a particular geographical network (10) forming between them a plurality of intersections (I1-I6). This method comprises a destination intersection selection step in which a carrier node (S) of the packets (P) selects a destination intersection (12) from neighbor intersections and according to traffic conditions; a step of seeking one or more neighbor mobile nodes (1) of the packet carrier node nearer the selected destination intersection (12) than the carrier node; and, if one or more neighbor mobile nodes (1) are found, a step of transferring the packets (P) from the packet carrier node (S) to the neighbor node (1) that has been found, so as to route the data packets to the selected destination intersection.

Claims

1. A method of routing one or more data packets (P) between a source node (S) and a target node (C) in an ad hoc network comprising a plurality of mobile nodes (1-14;

R0-R5) moving on traffic routes (L1, L2, L3, C1, C2, C3) of a particular geographical network (10) forming between them a plurality of intersections (I1-I6;

Ii, I10, I20, I30;

In, In+1), wherein the method includes;

a step (E3) of a carrier node (1;

S) of a data packet (P) to be routed to the target node (C) selecting a destination intersection (I2;

I20) from candidate neighbor intersections as a function of traffic conditions;

a step (E7;

E9) of seeking one or more neighbor mobile nodes (2, 3) of the carrier node (1) of the data packet (P) nearer the selected destination intersection (I2) than the carrier node; and

if one or more neighbor mobile nodes (2) is found, a step (E13) of transferring the data packet (P) from the carrier node (1) of the data packet to said neighbor node (2) that has been found so as to route said data packet toward the selected destination intersection (I2).

2. The method according to claim 1, wherein the step (E3) of selecting a new destination intersection is executed if the carrier node (1) of the data packet is located (E5) at the selected destination intersection, referred to as the current intersection.

3. The method according to claim 2, wherein during the selection step (E3) the carrier mobile node (1;

S) of the data packet selects a destination intersection (I2;

I20) from the candidate intersections as a function of one or more real time traffic conditions on a traffic route connecting the respective candidate intersection (I2;

I20) to the current intersection (I1;

Ii).

4. The method according to claim 1, wherein said carrier mobile node (1;

S) selects the destination intersection (I2;

I20) from the candidate intersections as a function of the proximity of the candidate intersection (I2;

I20) to the target node (C).

5. The method according to claim 1, wherein if no neighbor mobile node (2) is found in the search step (E7-E9), the carrier node carries the packet until it detects a new neighbor node.

6. The method according to claim 1 wherein each node maintains up-to-date measurements relating to the position, speed and direction of movement of its neighbor nodes and the step of seeking one or more neighbor mobile nodes of the carrier node of the data packet nearer the selected destination intersection than the carrier node includes a prediction step (E9) in which the current position of a neighbor node is calculated at a current time from these measurements.

7. The method according to claim 1 wherein said carrier mobile node (1;

S) selects from the candidate intersections the destination intersection (I2;

I20) having a maximum score (Sj), that score being calculated using the following formula;

Sj=α

×

f(T_ij)+β

×

g(D_j), where

T_ij represents the traffic density of nodes moving between the current intersection (Ii) and the destination intersection (Ij);

D_j represents the distance along the curve of the routing path that connects the destination intersection (Ij) to the target node (C);

α and

β

represent correction factors;

f is a density function of the road traffic such that 0≦

f(T_ij)≦

1; and

$g<br><br>\left(D_j\right)=1-\frac{D_j}{D_i},$

such that −

1≦

g(Dj)≦

1, where Di is the distance between the current intersection (Ii) and the target node (C).

10. A computer program including instructions for executing the steps of the routing method according to claim 1 when said program is executed by a computer.

11. A computer-readable storage medium storing a computer program comprising instructions for executing the steps of the routing method according to claim 1.

8. A communications terminal adapted to be used by a mobile node (1;

S) of an ad hoc network for routing data packets (P) to a target node (C) of the ad hoc network, said ad hoc network comprising a plurality of mobile nodes (1-14) moving on traffic routes (L1, L2, L3, C1, C2, C3) of a particular geographical network (10) forming between them a plurality of intersections (I1, I2, I3, I4, I5, I6;

Ii, I10, I20, I30;

I_n, I_n+1), wherein said terminal comprises;

means for selecting a destination intersection (I2;

I20) from neighbor intersections as a function of traffic conditions;

means for seeking a neighbor mobile node nearer the selected destination intersection than said mobile node; and

means for transferring the data packets (P) to the neighbor mobile node that has been found if the result of the search is positive.

9. A wireless communications system comprising mobile nodes (1 to 14) interconnected in an ad hoc structure and moving on traffic routes (L1, L2, L3, C1, C2, C3) of a particular geographical network (10) forming between them intersections (I1, I2, I3, I4, I5, I6;

Ii, I10, I20, I30), wherein said nodes are equipped with a communications terminal according to claim 8.