KR101626326B1 - Channel information storing method and communication method - Google Patents

Abstract

A channel information storing method and a communication method are disclosed. A channel information section for extracting channel information according to the position and time of the sensor module and transmitting the channel information to the transceiver, a transmission module for equalizing the transmission channel with channel information, controlling transmission power, and a reception module for equalizing the reception channel with channel information. Therefore, it is possible to reflect the previously measured channel information to the sensor node without complicated process of measuring the characteristics of the channel in real time.

Description

Technical Field [0001] The present invention relates to a channel information storing method,

The present invention relates to a channel information storing method and a communication method, and more particularly, to a channel information storing method and a communication method for communicating using stored channel information.

In the wireless communication standard supporting the sensor network operating at low power such as IEEE 802.15.4, the main object is simple and low power consumption sensor node. For this reason, considerable restrictions are imposed on the sensor's transmission speed and range. First, a channel equalizer is not provided to have a simple transceiver structure. For this reason, the sensor node can not know which channel environment it is transmitting or receiving. Therefore, proper channel equalization and power control are difficult to achieve. Due to the limitations of channel equalization and power control, wireless sensor nodes based on IEEE 802.15.4 have significant weaknesses in terms of communication speed, coverage, and battery life.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a channel information storing method and a communication method in which communication performance is improved by using predetermined channel information.

According to another aspect of the present invention, there is provided a method of measuring a channel characteristic of a mobile communication system, the method comprising: measuring a movement path by receiving a GPS signal; measuring a channel characteristic along the movement path; and storing the measured channel characteristic in a channel information database .

According to another aspect of the present invention, there is provided a method for measuring channel characteristics, comprising the steps of measuring a movement time, measuring a channel characteristic along the movement time, and storing the measured channel characteristic in a channel information database.

According to another aspect of the present invention, there is provided a method for controlling an information processing apparatus, the method comprising: extracting channel information from a channel information database according to a position of a sensor module; transmitting extracted channel information to a transceiver; And performing the equalization.

 According to still another aspect of the present invention, there is provided a method for controlling a sensor module including extracting channel information from a channel information database according to a time of a sensor module, transmitting extracted channel information to a transceiver, And performing the equalization.

Here, the transceiver further includes a step of controlling transmission power with the extracted channel information.

At this time, if the difference between the expected position of the sensor module and the actual position measured through the GPS exceeds a certain level, the transceiver further includes performing communication in a default state.

At this time, the transceiver further includes performing communication in a default state when the packet error rate exceeds a certain level.

According to another aspect of the present invention, there is provided a communication system including a channel information part for extracting channel information according to a location and time of a sensor module and transmitting the channel information to a transceiver, a transmission module for equalizing a transmission channel with channel information, And provides a receiving module for equalizing the receiving channel with channel information.

Here, the transmitting module and the receiving module perform communication in a default state when the difference between the expected position of the sensor module and the measured actual position through the GPS exceeds a certain level.

At this time, the receiving module performs communication in a default state when the packet error rate exceeds a certain level.

When the channel information storing method and the communication method according to the present invention as described above are used, it is possible to reflect previously measured channel information in the sensor node without complicated process of measuring the channel characteristics in real time.

Further, it is possible to manufacture a communication module capable of transmitting and receiving according to the characteristics of a channel at a low cost. This makes it possible to communicate at higher speeds.

Also, since the conventional IEEE 802.15.4 does not consider channel equalization, one chip section should be relatively long. However, applying the proposed technique can increase the communication speed while maintaining a simple structure.

Also, since the magnitude of the transmission power can be adjusted according to the characteristics of the channel, the power efficiency can be increased.

1 is a block diagram illustrating a configuration of a channel communication module according to an embodiment of the present invention.
2 is a block diagram illustrating a configuration of a communication module according to an embodiment of the present invention.
3 is a flowchart illustrating a method of storing channel information according to an exemplary embodiment of the present invention.
4 is a flowchart illustrating a method of communicating with channel information according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, A, B, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

TECHNICAL FIELD The present invention relates to a technique for improving communication efficiency in a wireless sensor network. A mobile wireless sensor network is a low-cost, low-power communication technology, and Zigbee or 6LoWPAN is widely used in IEEE 802.15.4-based. The present invention proposes an efficient communication method when a wireless sensor node moves along a predetermined path.

The present invention proposes a technique for easily achieving channel equalization and power control without adding a new channel measurement function in a conventional IEEE 802.15.4-based communication module. The present invention relates to a sensor module that improves communication performance at low cost by reusing predetermined channel information based on the fact that the channel characteristic is hardly changed with time when a fixed path is repeatedly moved due to the characteristics of a sensor node Production is possible.

When the sensor node moves along the fixed path, the communication efficiency can be improved based on the measured data without measuring the characteristics of the communication channel in real time by utilizing the movement route information of the sensor node.

Typical examples of sensor nodes that move along fixed paths include trains, buses, and mobile robots that are needed for the production process. In the case of trains, the route from the departure point to the destination is fixed, and the speed of train travel does not change greatly with each operation. And the environment around the railroad is also predictable to some extent according to time or season.

In the present invention, a channel equalizer and a transmission power control of a transmitter are implemented using a channel measurement technique using a pilot transmission based on the characteristics of the fixed-path movement sensor node. I suggest. The invention is largely composed of three steps.

 (1) a pre-measurement step of information of the channel

When the movement path and the movement time of the sensor module are determined, the sensor module measures the characteristics of the channel between the communication source and the destination while moving. It emits the pilot pattern determined by the communication source, receives and analyzes the pilot at the receiving end, and grasps the characteristics of the channel. In this case, the sensor module should move in the same way as the actual movement path and move the same as the actual movement speed. The channel information of the corresponding section is recorded according to the position of the sensor module. This information can be used to prepare multiple sets of data in time. That is, if the characteristics of the channel can be changed depending on whether it is weekday or weekend, the movement time of the sensor module may be changed depending on the AM or PM. And a database of channel information according to time is recorded by recording it in advance. The data thus created is stored in the channel information block in the sensor communication module of FIG.

(2) Application of Recorded Channel Information

When the sensor module actually moves according to the path, the channel information block of the sensor communication module of FIG. 1 extracts the channel information from the channel information database according to the position time of the current sensor module, and transmits the extracted channel information to the transmitter. The sensor communication module can obtain accurate information about the current time and its position by using the GPS module. If there is very little change in the travel path and travel speed of the sensor module, the current position can be grasped only with the departure time of the sensor module without using GPS. In the transmitter block, appropriate transmission power and modulation technique can be determined based on previously measured channel information. In the receiver block, channel equalization is performed based on previously measured channel information.

(3) adaptive application step according to the situation

If the difference between the expected position of the sensor module and the actual position measured by the GPS exceeds a certain level or the packet error rate exceeds a certain level, the technique of utilizing the previously measured channel information is stopped and the existing default state Communication is performed to prevent continuous communication errors.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a configuration of a channel communication module according to an embodiment of the present invention.

The device configuration of the channel communication module 100 includes a GPS module 110 for measuring a movement path; A measurement module 120 for measuring the characteristics of the channel; And a storage module 130 for storing channel information. The channel communication program is executed by the processor to cause the channel communication module 100 to operate.

The processor executes the executable code of the memory, and the memory stores the executable code and data. An embodiment of the channel communication module 100 configured based on the device configuration is as follows.

The GPS module 110 receives the GPS signal, calculates the position, and measures the movement path.

The measurement module 120 measures the characteristics of the channel along the movement path. The measurement module 120 transmits the measured channel characteristics to the storage module 130. The measurement module 120 may adjust the storage resolution of the channel characteristics by determining the degree of change of the channel characteristics according to the movement path. When the degree of change of the channel characteristic according to the movement path is small, the measurement module 120 sets the movement path to be long and sets the movement path to be short if the degree of change of the channel characteristic according to the movement path is large. The measuring module 120 measures characteristics of a channel by setting a travel path to be long if the degree of change of the channel characteristic is small and measures characteristics of the channel by setting a short travel path when the degree of change of the channel characteristic is large.

The storage module 130 stores the channel characteristics measured according to the movement path in the channel information database. The storage module 130 stores the movement path and the channel characteristics in the channel information database.

In another embodiment, the measurement module 120 measures the travel time and measures the characteristics of the channel along the travel time. The measurement module 120 may measure the movement time. The measurement module 120 measures the channel characteristics for each movement time and transmits the measured channel characteristics to the storage module 130. [ The measurement module 120 may adjust the storage resolution of the channel characteristics by determining the degree of change of the channel characteristics according to the movement time. If the degree of change of the channel characteristic according to the movement time is small, the measurement module 120 sets the movement time to be long and sets the movement time to be short if the degree of change of the channel characteristic according to the movement time is large. The measurement module 120 measures the characteristics of the channel by setting the movement time to be long if the degree of change of the channel characteristic is small and sets the movement time to short if the degree of change of the channel characteristic is large.

The storage module 130 stores the channel characteristics measured for each movement time in the channel information database. The storage module 130 stores the movement time and channel characteristics in the channel information database.

2 is a block diagram illustrating a configuration of a communication module according to an embodiment of the present invention.

The device configuration of the communication module 200 includes a GPS module 210, a channel information part 220, a transmitting module 230, and a receiving module 240. The program is executed by the processor to cause the communication module 200 to operate.

The processor executes the executable code of the memory, and the memory stores the executable code and data. An embodiment of the communication module 200 configured based on the device configuration is as follows.

The GPS module 210 receives the GPS signal, calculates the position, and measures the movement path.

The channel information unit 220 extracts channel information from the channel information database according to the position of the GPS module that measures the position and transmits the extracted channel information to the transmission module 230 and the reception module 240.

The transmission module 230 controls transmission power based on the extracted channel information. The transmission module 230 controls the transmission power according to the transmission channel indicated by the channel information.

The receiving module 240 performs channel equalization on the received channel with the extracted channel information.

The transmitting module 230 and the receiving module 240 perform communication in a default state when the difference between the expected position of the sensor module and the measured actual position through the GPS module 210 exceeds a certain level.

In another embodiment, a timer may be configured instead of the GPS module 210. [ The timer measures the time and outputs the time information to the channel information unit 220.

The channel information unit 220 extracts channel information from the channel information database according to the time of the sensor module and transmits the extracted channel information to the transmission module 230 and the reception module 240.

The transmission module 230 determines the characteristics of the transmission channel with the extracted channel information and controls transmission power.

The receiving module 240 performs channel equalization on the received channel with the extracted channel information.

The receiving module 240 performs communication in a default state when the packet error rate exceeds a certain level.

3 is a flowchart illustrating a method of storing channel information according to an exemplary embodiment of the present invention.

A method of storing channel information will be described.

The channel communication module includes a program memory for storing a program, a data memory for storing data, and a processor for executing the program.

Referring to the data stored in the program memory, the program memory includes a step 310 of measuring a movement path by receiving a GPS signal, a step 320 of measuring a characteristic of the channel along the movement path, (Step 330).

The channel communication module executes the program stored in the program memory by the processor, and the operation will be described as follows.

The procedure executed in the channel communication module is described in time series.

The channel communication module receives the GPS signal, calculates the position, measures the movement path to the calculated position (310), measures the characteristic of the channel along the movement path (320), stores the measured channel characteristic in the channel information database (330). The channel communication module can adjust the storage resolution of the channel characteristic by determining the degree of change of the channel characteristic according to the movement path. When the degree of change of the channel characteristic according to the movement path is small, the channel communication module sets the movement path to be long and sets the movement path to be short if the degree of change of the channel characteristic according to the movement path is large. The channel communication module measures the channel characteristics according to the adjusted travel path.

In another embodiment, instead of calculating the position, the channel communication module can measure the travel time and measure the characteristics of the channel along the travel time. The channel communication module can indicate the movement position by the movement time. The channel communication module can adjust the storage resolution of the channel characteristic according to the movement time by determining the degree of change of the channel characteristic. When the degree of change of the channel characteristic is low, the channel communication module sets the movement time to be long and sets the movement time to be short if the degree of change of the channel characteristic is high. The channel communication module can measure the channel characteristics at the adjusted travel time.

The channel communication module stores the measured channel characteristics in the channel information database. The channel communication module stores the movement time and channel characteristics in the channel information database.

4 is a flowchart illustrating a method of communicating with channel information according to an embodiment of the present invention.

A method of communicating with channel information will be described.

The communication module includes a program memory for storing a program, a data memory for storing data, and a processor for executing the program.

The program memory includes a step 410 of measuring a movement path by receiving a GPS signal, a step 420 of extracting channel information from a channel information database according to the position of the sensor module, A step 440 of performing channel equalization using the extracted channel information, a step 440 of performing channel equalization using the extracted channel information, a step 440 of, if the difference between the expected position of the sensor module and the actual position measured through the GPS module exceeds a certain level And performing (450) communication in a default state.

The communication module executes the program stored in the program memory by the processor, and the operation will be described as follows.

Procedures executed in the communication module are described in time series.

The communication module receives the GPS signal, measures the movement path (410), extracts channel information from the channel information database according to the position of the sensor module (420), controls transmission power with the extracted channel information (430) The channel equalization is performed with the extracted channel information (440). If the difference between the expected position of the sensor module and the actual position measured through the GPS module exceeds a specific level, communication is performed in a default state (450). The communication module performs communication in a default state when the movement position measured by the sensor module measuring the movement position is out of the predetermined movement position.

In another embodiment, the communication module may measure the travel time instead of measuring the location. The communication module measures the time, extracts channel information from the channel information database according to the time of the sensor module, and transmits the extracted channel information to the transmitting module and the receiving module. The communication module determines the movement position by the measured time and extracts the channel information from the channel information database according to the time.

The communication module determines the transmission channel with the channel information extracted from the channel information database, controls the transmission power, performs channel equalization with respect to the reception channel with the extracted channel information, and when the packet error rate of the reception channel exceeds a certain level, Lt; / RTI >

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

100: channel communication module 110: GPS module
120: Measurement module 130: Storage module

Claims (10)

A communication method of a node moving on a fixed movement path includes:
The channel communication module radiating a pilot pattern for pre-channel information measurement to determine a channel characteristic between a source and a destination according to a position and a time on the fixed movement path;
Storing the channel communication module in an information channel information database for the channel characteristics;
Extracting current channel information from the channel information database using the GPS (Global Positioning System) module or the location information and time information determined based on the movement time as input information; And
Wherein the communication module controls transmission power based on the current channel information and performs channel equalization,
Wherein the channel communication module sets the storage resolution of the channel characteristic differently considering the degree of change of the channel characteristic. The method according to claim 1,
Wherein the channel communication module sets the change value of the position and the change value of the time for determining the channel characteristic differently according to the degree of change of the channel characteristic. 3. The method of claim 2,
Wherein the communication module performs communication in a default state without considering the channel information when the difference between the position information, the time information, the position stored in the channel information database, and the time is greater than or equal to a specific level How to. The method of claim 3,
Wherein the information on the channel characteristics is classified into whether the channel characteristic is weekday or weekend, whether it is morning or afternoon, and is stored in the channel information database. A node moving on a fixed movement path,
A channel communication module configured to determine a channel characteristic between a source and a destination according to a position and a time on the fixed movement path, and to store information on the channel characteristic in a channel information database; And
Extracts current channel information from the channel information database using position information and time information determined based on a global positioning system (GPS) module or a movement time as input information, controls transmission power based on the current channel information, And a communication module for performing the communication,
Wherein the channel communication module sets the storage resolution of the channel characteristic differently considering the degree of change of the channel characteristic. 6. The method of claim 5,
Wherein the channel communication module sets the change value of the position and the change value of the time for determining the channel characteristic differently according to the degree of change of the channel characteristic. The method according to claim 6,
Wherein the communication module performs communication in a default state without considering the channel information when the difference between the position information, the time information, the position stored in the channel information database, and the time is greater than or equal to a specific level Node. 8. The method of claim 7,
Wherein information on the channel characteristics is separately classified into whether the channel is weekdays, weekends, morning or afternoon, and is stored in the channel information database. delete delete

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