Real-time wireless sensor network protocol having linear configuration

• US 20070140303A1
• Filed: 12/27/2005
• Published: 06/21/2007
• Est. Priority Date: 12/21/2005
• Status: Active Grant

• Current Assignee: Korea Electronics Technology Institute (Government of South Korea)
• Original Assignee: Korea Electronics Technology Institute (Government of South Korea)
• Inventors: Kim, Seong-Dong, Kim, Jae-Ho, Ahn, Il-Yeup, Lee, Sang-Shin, Won, Kwang-Ho
• Granted Patent: US 7,885,251 B2
• Time in Patent Office: Days
• US Class Current: 370/503
• CPC Class Codes: B61L 27/53 for trackside elements or systems, e.g. trackside supervision of trackside control system conditions
• CPC Class Codes: H04J 3/0652 Synchronisation among time division multiple access [TDMA] nodes, e.g. time triggered protocol [TTP] bus network with centralized control in which slots are of a TDMA packet structure H04L12/4035
• CPC Class Codes: H04J 3/0655 using timestamps
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A network configuration method of a sensor network configured to collect sensed data from a plurality of sensor nodes comprising: arranging linearly a path of respective node so as to enable all sensor nodes except for a sink node and a terminal node to have respectively a predecessor and a successor; and setting the time synchronization of whole network by fixing the each node take its own time synchronization on the basis of an operation section of the predecessor.

Claims

1. A network configuration method of a sensor network configured to collect sensed data from a plurality of sensor nodes comprising:

arranging linearly a path of respective node so as to enable all sensor nodes except for a sink node and a terminal node to have respectively a predecessor and a successor; and

setting the time synchronization of whole network by fixing the each node take its own time synchronization on the basis of an operation section of the predecessor.

2. The network configuration method of claim 1, wherein the step of setting the time synchronization includes:

a) synchronizing a transmission section of the successor of the sink node to reception section of the sink node;

b) synchronizing a transmission section of a lower successor to reception section of the successor; and

c) performing time synchronization of whole network by performing repeatedly the b) step.

3. The network configuration method of claim 1, wherein the respective nodes take the allocation of transmission/receipt time in a manner of time division multiple access.

11. A sensor node configured to perform a method as described in one of claim 1 and claim 4 comprising:

a high priority buffer configured to store temporarily emergency data; and

a low priority buffer configured to store temporarily general data;

wherein when a transmission packet is generated, the emergency data temporarily stored in the high priority buffer are included firstly in the transmission packet, and when a remainder is existed in a data field of the transmission packet, the general data temporarily stored in the low priority buffer are included in the transmission packet.

4. A data transmission method of a sensor network configured to collect sensed data and of which respective node has a serially linear structure of communication path comprising:

a) synchronizing the operation interval of the respective nodes to an operation interval of a predecessor;

b) enabling an arbitrary node in the sensor network to receive data transmitted from the successor in its own receipt interval;

c) enabling the arbitrary node to confirm whether the transmitted data are normal;

d) enabling the arbitrary node to transmit the data to the predecessor in its own transmission interval, when the data are normal.

5. The data transmission method of claim 4, wherein the step of d) comprises:

generating a transmission packet including data from the successor and/or data detected by the arbitrary node itself;

inserting an ACK signal into the transmission packet; and

transmitting simultaneously the transmission packet to the predecessor and the successor.

6. The data transmission method of claim 5, further comprises:

retransmitting by the arbitrary node in a next transmission interval when the transmission packet is not received from the predecessor; and

considering that the transmission has been successful and deleting data in its own buffer by the arbitrary node when said transmission packet is received to the predecessor.

7. The data transmission method of claim 5, wherein the transmission packet includes an identifier of a node which sense data, a data type identifier which represents a data type and the detected data.

8. A new node joining method of a sensor network which collects sensed data from a plurality of sensor nodes, and of which respective node has a communication path of a series of linear configuration, comprising:

enabling a present terminal node in an end of the linear configuration sensor network to broadcast periodically a hello message for informing its own presence;

enabling one or more sensor nodes which desire to be newly joined to the sensor network to calculate a link connection quality from a signal state of the hello message received to itself;

enabling the sensor node having the highest link connection quality to communicate a preemption message;

enabling the sensor node to transmit a join message to the present terminal node in a next interval after broadcasting the preemption message; and

enabling the sensor node to advertise that the node has been become a new terminal node, when the sensor node receives an ACK message corresponding to the join message.

9. The new node joining method of claim 8, wherein the step of broadcasting the preemption message includes:

broadcasting the preemption message in order of a sensor node which the computed link connection quality is higher; and

delaying a new join of neighboring nodes by receiving the preemption message.

10. An inter-node communication path rearrangement method of a sensor network configured to collect detecting data from a plurality of sensors and of which respective node has a serially linear communication path, and has its own network ID and a fewer ID value in inversely proportion to a predecessor, comprising:

converting an arbitrary node which is transmitted from its own predecessor but does not receive an ACK signal into a receipt standby state;

enabling the receipt standby node to transmit a join message to a node having a lower ID value and the fewest difference between them among its own neighboring nodes; and

setting a node of the transmitted response message as its own predecessor, when the receipt standby node receives a response message corresponding to the join message.