Method of transmitting/receiving data in sensor network for reducing overhearing of sensor nodes

• US 20090103437A1
• Filed: 04/29/2008
• Published: 04/23/2009
• Est. Priority Date: 10/22/2007
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute, University-Industry Cooperation Foundation of Korea Aerospace University
• Inventors: Kim, Nae-Soo, Pyo, Cheol Sig, Kim, Se Han, Lee, Kyeseon, Yoon, Chong-Ho, Byun, Gang-Ho
• Granted Patent: US 8,089,909 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 7/041 using special codes as synchronising signal
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Provided is a method of transmitting/receiving data in a sensor node for reducing overhearing of sensor nodes, and a sensor network which implements the method. A sender node having transmission data from among a plurality of nodes which perform a low power listening (LPL) operation in an asynchronous manner at predetermined time intervals, generates a long preamble including short preambles, each having information including a destination address of the transmission data, a remainder of the long preamble, and a length of the transmission data, and sequentially transmits the second preamble and the transmission data. A receiver node from among the plurality of nodes determines whether a valid signal is sensed during an active state in the LPL operation. If it is determined that the valid signal is sensed, the receiver node receives the short preamble transmitted from the sender node. The receiver node determines a duration time of a deactivated state of the receiver node based on the received first preamble, thereby reducing overhearing in the sensor network.

Claims

1. A method of transmitting data in a sensor network by a sender node having transmission data from among a plurality of nodes which perform a low power listening (LPL) operation in an asynchronous manner at predetermined time intervals, the method comprising:

generating a second preamble comprising at least one first preamble; and

sequentially transmitting the second preamble and the transmission data,

wherein each of the at least one first preamble comprises information regarding a destination address of the transmission data, a remainder of the second preamble at a time position of the first preamble, and a length of the transmission data.

2. The method of claim 1, further comprising maintaining a deactivated state until a point of time of a next LPL operation after the sequential transmission of the second preamble and the transmission data.

3. The method of claim 1, wherein each of the at least one first preamble further comprises a preamble for bit synchronization and a start frame delimiter (SFD) indicating start of valid information in units of bytes.

4. The method of claim 1, wherein a length of the second preamble is longer than a sum of the predetermined time interval, a length of each of the at least one first preamble, and a length of a time interval during which the LPL operation is performed.

5. The method of claim 1, wherein the plurality of nodes perform the LPL operation at different points in time.

6. The method of claim 1, wherein the plurality of nodes use media access control (MAC).

7. A method of receiving data in a sensor network by a receiver node from among a plurality of nodes which perform a low power listening (LPL) operation in an asynchronous manner at predetermined time intervals, the method comprising:

determining whether a valid signal is sensed during an active state in the LPL operation;

receiving a first preamble transmitted from a sender node, which transmits the valid signal, from among the plurality of nodes; and

determining a duration time of a deactivated state of the receiver node based on a destination address of data transmitted by the sender node, a remainder of a second preamble including the received first preamble at a time position of the received first preamble, and a length of the data from among information included in the received first preamble.

8. The method of claim 7, further comprising:

switching to the deactivated state based on the determined duration time of the deactivated state of the receiver node;

receiving the data transmitted by the sender node after the duration time of the deactivated state of the receiver node if the receiver node is included in the destination address of the data; and

maintaining the deactivated state until a point of time of a next LPL operation.

9. The method of claim 7, wherein the reception of the first preamble comprises:

determining whether the reception of the first preamble is complete;

determining whether a predetermined valid time for the reception of the first preamble has expired if the reception of the first preamble is not complete;

repeating determining whether the reception of the first preamble is complete if the predetermined valid time has not expired.

10. The method of claim 7, wherein the determination of the duration time of the deactivated state of the receiver node comprises:

determining whether the receiver node is included in the destination address of the data;

determining the duration time of the deactivated state of the receiver node based on a time interval corresponding to the remainder of the second preamble at the time position of the received first preamble if it is determined that the receiver node is included in the destination address of the data; and

determining the duration time of the deactivated state of the receiver node based on a sum of the time interval corresponding to the remainder of the second preamble at the time position of the received first preamble and a time interval corresponding to the length of the data if it is determined that the receiver node is not included in the destination address of the data.

11. The method of claim 7, wherein the first preamble further comprises a first preamble for bit synchronization and a start frame delimiter indicating a start of valid information in units of bytes.

12. The method of claim 7, wherein a length of the second preamble is longer than a sum of the predetermined time interval, a length of the received first preamble, and a length of a time interval during which the LPL operation is performed.

13. The method of claim 7, wherein the plurality of nodes perform the LPL operation at different points in time.

14. The method of claim 7, wherein the plurality of nodes use media access control (MAC).

15. A method of transmitting/receiving data in a sensor network, the method comprising:

sender node'"'"'s generating a second preamble comprising at least one first preamble for reducing overhearings of other nodes, where the sender node has transmission data and the sender node and the other nodes are from among a plurality of nodes which perform a low power listening (LPL) operation in an asynchronous manner at predetermined time intervals;

the sender node'"'"'s sequentially transmitting the second preamble and the transmission data;

receiver node'"'"'s determining whether a valid signal transmitted from the sender node is sensed during an active state in the LPL operation and receiving the first preamble transmitted from the sender node if it is determined that the valid signal is sensed, where the receiver node is from among the plurality of nodes; and

the receiver node'"'"'s determining a duration time of a deactivated state of the receiver node based on a destination address of the transmission data transmitted by the sender node, a remainder of the second preamble including the received first preamble at a time position of the received first preamble, and a length of the transmission data from among information included in the received first preamble.

16. The method of claim 15, further comprising, the sender node'"'"'s maintaining a deactivated state until a point of time of a next LPL operation after the sequential transmission of the second preamble and the transmission data by the sender node.

17. The method of claim 15, further comprising:

receiver node'"'"'s switching to the deactivated state based on the determined duration time of the deactivated state of the receiver node;

receiver node'"'"'s receiving the transmission data transmitted by the sender node after the duration time of the deactivated state of the receiver node or performing a next LPL operation.

18. An asynchronous sensor network comprising a plurality of nodes which perform a low power listening (LPL) operation in an asynchronous manner at predetermined time intervals, the asynchronous sensor network comprising:

a sender node, which is from among the plurality of nodes, generating a second preamble comprising at least one first preamble for reducing overhearing of other nodes if the sender node has transmission data, and sequentially transmitting the second preamble and the transmission data; and

a receiver node determining whether a valid signal transmitted from the sender node is sensed during an active state in the LPL operation, receiving the first preamble transmitted from the sender node if it is determined that the valid signal is sensed, and determining a duration time of a deactivated state of the receiver node based on a destination address of the transmission data transmitted by the sender node, a remainder of the second preamble at a time position of the received first preamble, and a length of the transmission data from among information included in the received first preamble.

19. The asynchronous sensor network of claim 18, wherein the plurality of nodes use media access control (MAC).