KR20150001399A - Wireless sensor node and method for communicating radio using the node - Google Patents

Abstract

The present invention relates to a wireless sensor node and a wireless communication method using the same which can efficiently transmit data using an RF power table when data are transmitted to another adjacent wireless sensor node in a ubiquitous sensor network (USN). The wireless sensor node according to the present invention comprises: an RF transmission and reception unit for transmitting and receiving data to and from each of wireless sensor nodes, adjusting transmission power based on a radio frequency (RF) power value set for each wireless sensor node, and transmitting data to each of the wireless sensor node; a state measurement unit for measuring a received signal strength value and a link quality value of each wireless sensor node using messages received from each of the wireless sensor node; and a control unit for setting an RF power value of each wireless sensor node using the measured received signal strength value and the link quality value. According to the present invention, by adjusting the transmission power of the RF transmission unit to optimize an RF power value using a received signal strength value and a quality value between adjacent wireless sensor nodes, interference between the adjacent wireless sensor nodes during transmission can be minimized, thereby optimizing communications.

Description

TECHNICAL FIELD [0001] The present invention relates to a wireless sensor node and a wireless communication method using the wireless sensor node.

The present invention relates to a wireless sensor node and a wireless communication method using the wireless sensor node. In a near-field wireless sensor network system such as a USN (Ubiquitous Sensor Network) system, efficient data And a wireless communication method using the wireless sensor node.

USN (Ubiquitous Sensor Network) system is one of the ubiquitous paradigm communication technologies that can be connected to the computing environment anytime and anywhere without being influenced by the place. Especially, as the ubiquitous paradigm expands, it is one of the technologies that are being actively studied all over the world.

In such a large-scale short-range wireless sensor network, such as the USN system, the important thing is to secure a network path capable of communication and communicate with the lowest possible output.

This is one of the biggest issues in the emerging USN system. It is a new transmission technology that enables communication with low output without inducing traffic of other nodes in order to reduce network load and efficiently manage network. Is required.

The technology to be the background of the present invention is described in Korean Patent Registration No. 10-0668228 (published on Jan. 16, 2007).

Accordingly, the present invention is directed to an apparatus and method for efficiently transmitting data using a radio frequency (RF) power table when data is transmitted to a nearby wireless sensor node in a near field wireless sensor network system such as a USN (Ubiquitous Sensor Network) system. And a wireless communication method using the same.

According to an aspect of the present invention, there is provided a wireless sensor node that transmits and receives data to and from each of a plurality of wireless sensor nodes, and controls transmission power based on a radio frequency (RF) An RF transceiver for transmitting data to each of the wireless sensor nodes; A status measuring unit measuring a received signal strength value and a link quality value for each wireless sensor node using a message received from each of the wireless sensor nodes; And a controller for setting an RF power value for each wireless sensor node using the measured received signal strength value and the link quality value.

Here, the wireless sensor node may further include a storage unit for storing at least one of the received signal strength value, the link quality value, and the RF power value, which is measured by matching the IDs of the wireless sensor nodes, in a table format.

Here, the control unit may set the RF power value by increasing or decreasing the RF power value according to the measured received signal strength value and whether the link quality value is included in the set range value.

Here, if the link quality value is smaller than the preset first reference value, the control unit increases the RF power value, and if the measured link strength value is a second reference value higher than the first reference value and the measured received signal strength value is greater than a predetermined first signal If the link quality value is a second reference value and the measured received signal strength value is greater than a second signal strength value that is greater than the first signal strength value, then the RF power value may be decreased have.

The wireless communication method of a wireless sensor node transmitting and receiving data to and from a plurality of wireless sensor nodes according to another embodiment of the present invention is a wireless communication method using a message received from each wireless sensor node, Measuring a quality value; Setting an RF power value for each wireless sensor node using the measured received signal strength value and the link quality value; And adjusting transmit power based on a set RF (Radio Frequency) power value to transmit data to the wireless sensor nodes, respectively.

As described above, according to the present invention, the transmission power of the RF transmitter is adjusted to have an optimal RF power value using the received signal strength value and the link quality value between adjacent wireless sensor nodes, thereby minimizing interference with the neighboring wireless sensor nodes It is possible to expect an effect of achieving optimal communication.

1 is a diagram illustrating a local area network system including a plurality of wireless sensor nodes according to an embodiment of the present invention.
2 is a block diagram of a wireless sensor node according to an embodiment of the present invention.
3 is a flowchart illustrating a method of storing an RF power table of a wireless sensor node according to an embodiment of the present invention.
4 is a flowchart illustrating a data transmission method of a wireless sensor node according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

FIG. 1 is a diagram illustrating a local area network system including a plurality of wireless sensor nodes according to an exemplary embodiment of the present invention. FIG. 2 is a diagram illustrating a wireless sensor node according to an exemplary embodiment of the present invention.

1 and 2, the local area network system includes a plurality of wireless sensor nodes 100. The wireless sensor node 100 includes a radio frequency (RF) transceiver 110, a state measuring unit 120, A storage unit 130, and a control unit 140.

The RF transmitting and receiving unit 110 performs RF transmission and reception with other nearby wireless sensor nodes 100 and controls the RF transmission power based on the set RF power value under the control of the control unit 140, ). ≪ / RTI >

The state measuring unit 120 measures received signal strength values (RSSI) and link quality values (LQI; Link (RSSI)) for each wireless sensor node 100 using messages received from nearby wireless sensor nodes 100. [ And stores the measured values in a storage unit 130. The storage unit 130 stores the measured values in a table. At this time, the state measuring unit 120 stores the Id (Identification), the received signal strength value (RSSI), the link quality value (LQI) of the corresponding wireless sensor node 100, .

The storage unit 130 stores an RF power table including ID (Identification) of a nearby wireless sensor node 100, a received signal strength value (RSSI), a link quality value (LQI), and an RF power value applied at the time of communication .

The control unit 140 controls data flow between the RF transceiver unit 110 and the status measuring unit 120 and the storage unit 130. When the data is transmitted to the adjacent wireless sensor node 100, The RF power value is set based on the received signal strength value and the link quality value of the RF power table stored in the RF power table and the transmission power of the RF transmitting and receiving unit 110 is controlled based on the set RF power value.

Referring to the RF power table stored in the wireless sensor node A 100-1 shown in FIG. 1, the status measuring unit 120 measures the surrounding wireless sensor nodes B 100 - 2, D 100 - The controller 140 measures the received signal strength value and the link quality value using a message received from the F 100-6 and the F 100-6 and stores the received signal strength value and the link quality value in the storage unit 130, And transmits the data to the peripheral wireless sensor nodes 100-2, 100-4, 100-5, and 100-6 at the optimal transmission power by setting the RF power value of the wireless sensor node 110. [

3 and 4, the wireless sensor node A 100-1 and the wireless sensor nodes 100-2, 100-3, 100-4, 100-5, 100-6, and 100-n, The wireless communication method will be described in detail.

FIG. 3 is a flowchart illustrating a method of storing an RF power table of a wireless sensor node according to an embodiment of the present invention, and FIG. 4 is a flowchart illustrating a method of transmitting data by a wireless sensor node according to an embodiment of the present invention.

3, a method of storing the RF power table of the wireless sensor node A 100-1 will be described. Then, using the RF power table stored in FIG. 4, the wireless sensor node A 100-1 transmits data Will be sequentially described below.

3, the RF transmitting / receiving unit 110 of the wireless sensor node A 100-1 receives a message from the surrounding wireless sensor node B 100-2 (S300), and the state measuring unit 120 (Id), the link quality value (LQI) and the received signal strength value (RSSI) of the wireless sensor node B (100-2) in the RF power table using the message received from the RF transceiver unit 110 (S302).

The control unit 140 determines whether the link quality value LQI of the stored RF power table is less than 90% at step S304. If the link quality value LQI is less than 90% at step S304, The RF power value included in the RF power table of the wireless sensor node B 100-2 stored in the wireless sensor node 130 is increased by a predetermined value and stored (S306).

At this time, the control unit 140 stores the preset basic RF power value in the RF power table when receiving the first message from the wireless sensor node C (100-3) and registering it (in the case of newly connected wireless sensor node) , And transmits data based on the stored basic RF power value at the time of initial data transmission to the wireless sensor node C (100-3).

If it is determined in step S304 that the link quality value LQI is not less than 90%, the controller 140 determines whether the link quality value LQI is 100% (S308).

If it is determined in step S308 that it is not 100%, the controller 140 repeats steps S300 through S304. That is, the control unit 140 waits until the next message is received from the wireless sensor node B 100-2.

If it is determined in step S308 that the received signal strength value RSSI is 100%, the controller 140 determines whether the RSSI received from the wireless sensor node B 100-2 is less than a predetermined minimum received signal strength value (S310).

If it is determined in step S310 that the received signal strength value is smaller than the minimum received signal strength value, the controller 140 controls the RF power table of the wireless sensor node B 100-2 stored in the storage unit 130 The RF power value included therein is increased by the set value and stored (S306).

If it is determined in step S310 that the received signal strength value is not less than the preset minimum received signal strength value, the controller 140 determines whether the received signal strength value is greater than a predetermined maximum received signal strength value in step S312.

If it is determined in step S312 that the received signal strength value is not greater than the preset maximum received signal strength value, the controller 140 repeats steps S300 through S310. That is, the control unit 140 waits until the next message is received from the wireless sensor node B 100-2.

If it is determined in step S312 that the received signal strength value is greater than a predetermined maximum received signal strength value, the controller 140 determines whether the RF power table of the wireless sensor node B 100-2 stored in the storage unit 130 The RF power value included in the RF power is decreased by the set value and stored (S314).

Here, the quality value threshold, the minimum received signal strength value, and the maximum received signal strength value can be changed in accordance with the wireless communication environment.

Next, a wireless communication method for transmitting data to a wireless sensor node in proximity to the wireless sensor node will be described with reference to FIG.

4, when there is data to be transmitted to the wireless sensor node B 100-2, the control unit 140 of the wireless sensor node A 100-1 transmits the data to the wireless sensor node B 100-2 Id is stored in the RF power table (S400).

If Id of the wireless sensor node B 100-2 is not stored in the RF power table as a result of the determination in S400, the control unit 140 does not transmit data and the wireless sensor node B (100-2) And waits until the RF power table is generated through the received message.

If the Id of the adjacent wireless sensor node 100-2 is stored in the RF power table as a result of the determination in S400, the controller 140 controls the RF power of the RF transceiver 110 Power is set (S402), and data is transmitted with the set RF power (S404).

In step S406, the controller 140 determines whether a response message corresponding to the transmitted data is received from the wireless sensor node B 100-2 within a predetermined period of time to determine whether transmission of the transmitted data is successful or not (step S406) .

As a result of the determination in step S406, when receiving a response message from the wireless sensor node B 100-2, the controller 140 determines that the data transmission is well performed and ends the transmission.

If it is determined in step S406 that the response message is not received from the wireless sensor node B 100-2, the control unit 140 increments the number of transmissions by 1 and then determines whether the number of transmissions is smaller than the predetermined maximum number of transmissions (S408). If it is determined in step S408 that the number of transmissions is not smaller than the predetermined maximum transmission number (equal to or greater than the predetermined maximum number of transmissions), the control unit 140 ends the data transmission.

If it is determined in step S408 that the number of transmissions is less than the predetermined maximum number of transmissions, the control unit 140 increases the RF power value of the RF transmitting and receiving unit 110 by a predetermined value to retransmit the data to a higher RF output (S410 , And the RF power value of the RF power table is increased by the set value and stored in the RF power table (S412). Thereafter, the control unit 140 repeats steps S402 to S408.

According to the present invention, by optimally adjusting the RF power value between adjacent wireless sensor nodes using the received signal strength value and the link quality value, it is possible to minimize the interference with the neighboring wireless sensor nodes during transmission, There is a big advantage.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: wireless sensor node 110: RF transmitting /
120: state measuring unit 130:
140:

Claims (8)

An RF transmitting and receiving unit transmitting and receiving data to and from each of a plurality of wireless sensor nodes and transmitting the data to each of the wireless sensor nodes by adjusting transmission power based on an RF (Radio Frequency) power value set for each wireless sensor node;
A status measuring unit measuring a received signal strength value and a link quality value for each wireless sensor node using a message received from each of the wireless sensor nodes; And
And a controller for setting the RF power value for each of the wireless sensor nodes using the measured received signal strength value and the link quality value,
The wireless sensor node comprising: The method according to claim 1,
And a storage unit for storing at least one of the measured received signal strength value, the link quality value, and the RF power value in a tabular form, matching the ID of the wireless sensor nodes. 3. The method of claim 2,
Wherein,
And sets the RF power value by increasing or decreasing the RF power value according to the measured received signal strength value and whether the link quality value is included in the set range value. The method of claim 3,
Wherein,
Increases the RF power value if the link quality value is smaller than a predetermined first reference value,
Increases the RF power value if the link quality value is a second reference value higher than the first reference value and the measured received signal strength value is smaller than a predetermined first signal strength value,
And decreases the RF power value if the link quality value is the second reference value and the measured received signal strength value is greater than a second signal strength value that is higher than the first signal strength value. A wireless communication method for a wireless sensor node transmitting and receiving data to and from a plurality of wireless sensor nodes,
Measuring a received signal strength value and a link quality value for each wireless sensor node using a message received from each of the wireless sensor nodes;
Setting an RF power value for each wireless sensor node using the measured received signal strength value and the link quality value; And
And transmitting data to the wireless sensor nodes by adjusting transmission power based on the set RF (Radio Frequency) power value
Lt; / RTI > 6. The method of claim 5,
And storing at least one of the measured signal strength value, the link quality value, and the RF power value in a table format, in correspondence with an ID (Identification) of the wireless sensor nodes. The method according to claim 6,
The step of setting the RF power value comprises:
And the RF power value is set by increasing or decreasing the RF power value according to whether the measured signal strength value and the link quality value have a set range value. 8. The method of claim 7,
The step of setting the RF power value comprises:
Increasing the RF power value if the link quality value is less than a predetermined first reference value;
Increasing the RF power value if the link quality value is a second reference value higher than the first reference value and the measured received signal strength value is less than a predetermined first signal strength value; And
And decreasing the RF power value if the link quality value is the second reference value and the measured received signal strength value is greater than a second signal strength value that is higher than the first signal strength value.

Images