Automatic fall behind warning method and system

• US 8,130,678 B2
• Filed: 03/17/2009
• Issued: 03/06/2012
• Est. Priority Date: 01/19/2009
• Status: Expired due to Fees

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Lee, Kuen-Ming, Chu, Jenn-Lien, Sheng, Yu-Shiang
• Primary Examiner(s): Abelson, Ronald
• Application Number:
  US12/405,249
• Publication Number:
  US 20100184425A1
• Time in Patent Office: 1,085 Days
• Field of Search: 370/254, 370/255, 455/421, 455/456.1
• US Class Current: 370/255
• CPC Class Codes: H04L 41/0893 Assignment of logical groups to network elements
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 67/52 specially adapted for the location of the user terminal
• CPC Class Codes: H04L 67/55 Push-based network services
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 40/248 Connectivity information update

Abstract

Disclosed relates to an automatic fall behind warning method and system applied in a group activity environment. Each individual in the group corresponds to a node and all of such nodes form an independent network. The method initializes an outside node table for the group and gets a link quality index table (LQI table) among the nodes on the network. A table specifying outside and inside nodes for the network topology is generated via an algorithm. Then the method checks if there is a node being disappearing from the outside nodes of the generated table. If not, it updates the outside node table and continues to get a newest LQI table. If so, the node falls behind is confirmed and a warning notice is automatically generated once the disappearing node is not an inside node is verified. Otherwise, the method returns to the step of updating the outside node table.

Claims

1. An automatic fall behind warning method applicable to a group activity environment, comprising the steps of:

(a) forming a network with a plurality of nodes each corresponding to a communication device carried by an individual participated in a group activity;

(b) initializing an outside node table consisting of all outside nodes determined by an outside determination algorithm according to initial topology of said network;

(c) obtaining a link quality index (LQI) table of said network, said LQI table having a plurality of connection entries with each connection entry specifying a connection between two nodes that are able to communicate and signal strength of the connection;

(d) generating a list specifying current inside nodes and current outside nodes determined by said outside determination algorithm according to current topology of said network;

(e) comparing the outside nodes in said outside node table with said current outside nodes specified in the generated list of step (d);

(f) if there is an outside node in said outside table disappears from said current outside nodes of step (d), proceeding to step (g);

otherwise, updating said outside node table with said current outside nodes of step (d) and returning to step (c);

(g) checking whether the disappearing outside node becomes one of said current inside nodes of step (d); and

(h) if the disappearing outside node is one of said current inside nodes of step (d), updating said outside node table with said current outside nodes of step (d) and returning to step (c);

otherwise, declaring that the disappearing outside node is falling behind and issuing a warning;

wherein said outside determination algorithm determines each node in the topology of said network as being either an inside node or an outside node with the outside node being a node located in an outskirt part of said group activity according to the topology of said network.

2. The method as claimed in claim 1, wherein said outside determination algorithm comprises the steps of:

(s1) connecting the nodes in the topology of said network according to the connections specified in the connection entries of said LQI table one by one by following the signal strength of the connections from the strongest to the weakest until at least a loop is formed by the nodes;

(s2) checking if there are any two loops formed with an overlapped path in step (s1);

(s3) for each overlapped path found in step (s2) if the overlapped path has one or more nodes in addition to a starting node and an ending node of the overlapped path, labeling each of the one or more additional nodes as an inside node;

(s4) returning to step (s1) if there are still nodes not connected according to the connection entries of said LQI table;

otherwise, proceeding to step (s5);

(s5) labeling each of the nodes that have not been labeled as an inside node as an outside node.

3. The method as claimed in claim 1, wherein in said group activity environment any communication device carried by an individual participated in the group activity is able to communicate with at least another communication device carried by another individual participated in the group activity except for a communication device whose corresponding node is falling behind.

4. The method as claimed in claim 1, wherein at least two individuals participated in the group activity.

5. The method as claimed in claim 1, wherein all nodes form said network through a common communication protocol.

6. The method as claimed in claim 1, wherein said method does not use relative position information of nodes in said network.

7. An automatic fall behind warning system applicable to a group activity environment, comprising a plurality of wireless communication devices each being carried by an individual participated in a group activity and corresponding to a node and a network formed by all the nodes, each wireless communication device comprising:

a network management intermediate module for managing network related information of each node;

an outside determination module for monitoring signal strength of neighboring nodes of each node and generating a list of inside nodes and outside nodes according to topology of the network;

a fall behind warning module for comparing the outside nodes saved in an outside node table with current outside nodes determined in current topology of the network to check whether any outside node in the outside node table disappears from the current outside nodes, automatically sending a fall behind warning if there is a disappearing outside node from the outside node table which has not become one of current inside nodes determined in the current topology of the network, and updating the outside node table with the current outside nodes;

a group management module for activating the network management intermediate module and managing network setting of each node; and

a wireless communication module for activating a wireless network to perform wireless communication among the nodes;

wherein each node in the topology of the network is determined by the outside determination module as being either an inside node or an outside node with the outside node being a node located in an outskirt part of the group activity according to the topology of the network.

8. The system as claimed in claim 7, wherein said outside determination module further comprises an link quality index (LQI) table of said network, said LQI table having a plurality of connection entries with each connection entry specifying a connection between two nodes that are able to communicate and signal strength of the connection.

9. The system as claimed in claim 8, wherein said outside determination module implements an outside determination algorithm comprising the steps of:

(s1) connecting the nodes in the topology of said network according to the connections specified in the connection entries of said LQI table one by one by following the signal strength of the connections from the strongest to the weakest until at least a loop is formed by the nodes;

(s2) checking if there are any two loops formed with an overlapped path in step (s1);

(s3) for each overlapped path found in step (s2) if the overlapped path has one or more nodes in addition to a starting node and an ending node of the overlapped path, labeling each of the one or more additional nodes as an inside node;

(s4) returning to step (s1) if there are still nodes not connected according to the connection entries of said LQI table;

otherwise, proceeding to step (s5);

(s5) labeling each of the nodes that have not been labeled as an inside node as an outside node.

10. The system as claimed in claim 7, wherein in said group activity environment any wireless communication device carried by an individual participated in said group activity is able to communicate with at least a wireless communication device carried by another individual participated in said group activity except for a wireless communication device whose corresponding node is falling behind, and wireless communication signal is used for network topology determination and message transmission.

11. The system as claimed in claim 7, said system implements each of said plurality of wireless communication devices via a same type of wireless communication device.

12. The system as claimed in claim 7, wherein said network management intermediate module initializes network information, allocates network address information, and updates information of neighboring nodes of each node, and routing information of communication protocol.

13. The system as claimed in claim 12, wherein said network management intermediate module further includes:

a one hop table for recording information of neighboring nodes of each node;

a routing table for recording routing information of said communication protocol; and

two fields for recording a specific network ID and an allocated network address of the node.

14. The system as claimed in claim 7, wherein each wireless communication device further includes a low power monitoring module for monitoring power and issuing a warning when the power is lower than a threshold.

15. The system as claimed in claim 7, wherein said group includes at least two individuals.

16. The system as claimed in claim 7, wherein said system describes the topology of said network with wireless signal coverage ranges of said wireless communication devices carried by individuals participated in said group activity.

17. The system as claimed in claim 7, wherein said system does not require equipment deployment in an external environment.

18. The system as claimed in claim 7, wherein said system does not deploy any equipment from the group consisting of GPS satellite, wireless base station and wireless sensor network.