KR20140072733A - Method for communication data of heterogeneous wireless network - Google Patents

Abstract

A method for data communication of heterogeneous wireless networks using the same frequency, which can minimize interference on data received and transmitted in the heterogeneous wireless networks. The method for data communication comprises: a step in which a master and a slaver, which are connected to each other through a wireless network, executing periodic data transmission/reception by sending and receiving a data transmission request signal (Req) and a data reception acknowledgement signal (Ack) through an occupied channel; a step in which the master detects a reception failure rate of the data reception acknowledgement signal (Ack) provided by the slave for a preset time period; a step in which the master searches for an idle channel if the reception failure of the data reception acknowledgement signal (Ack) exceeds a preset threshold 1; a step in which the master pauses the data transmission/reception with the slave if the reception failure of the data reception acknowledgement signal (Ack) exceeds a preset threshold 2, and transmits a channel hoping messaging together with the searched idle channel to the slave; and a step in which the master occupies the idle channel when receiving an acknowledgement signal (Ack) of the channel hopping message from the slave, and restarts the data transmission/reception through the idle channel.

Description

[0001] METHOD FOR COMMUNICATION DATA OF HETEROGENEOUS WIRELESS NETWORK [0002]

The present invention relates to a data communication method of a heterogeneous wireless network in which interference of data transmitted and received in a heterogeneous wireless network using the same frequency can be minimized.

In general, the physical layer and medium access control layer in the ZigBee network is defined by the IEEE 802.15.4 standard, and the 2.4 GHz Industrial Science Medical (ISM) band defined in the physical layer of IEEE 802.15.4 is used for industrial, And is used in Bluetooth and wireless LAN.

As the usage of wireless LAN increases along with the spread of smart phones, the ZigBee network that uses the same frequency band has a lot of interference. In particular, since the transmission power of the ZigBee network is small, I get a lot.

Such interference in the heterogeneous wireless network causes packet transmission to fail. Therefore, when the ZigBee network is specified for control requiring real-time property, the control quality deteriorates.

In the conventional technology, when interference occurs in a heterogeneous wireless network, communication is resumed after waiting until the occupation of the channel is released.

Generally, in an application such as a sensor network to which Zigbee communication is applied, since the real time transmission and reception of data is not important, there is no problem even if the communication is resumed after waiting until the channel is released.

However, in the real - time control application, the reaction time, which is an important factor for determining the performance, is caused to increase, which may degrade the performance of the system.

Patent Registration No. 10-0730238 (Jun. 19, 2007) Patent Registration No. 10-1171451 (Aug. 07, 2012)

SUMMARY OF THE INVENTION The present invention has been developed in order to solve such a problem, and an object of the present invention is to provide a heterogeneous network in which real time data transmission / reception is maintained by occupying an idle channel by channel hopping To provide a data communication method of a wireless network.

The feature of the present invention is that a master and a slave connected to a wireless network transmit and receive a data transmission request signal Req and a data reception acknowledge signal Ack through a channel occupied by the wireless network, process; Detecting a reception failure rate of a data reception acknowledgment signal (AcK) provided in a slave for a predetermined period of time; Searching for an idle channel if the reception failure rate of the data acknowledgment signal (Ack) exceeds the set threshold value 1; When the reception failure rate of the data acknowledgment signal (Ack) exceeds the set threshold value 2, the master stops transmitting and receiving data with the slave and transmits a channel hopping message together with the searched idle channel information; The master receives the acknowledgment signal (Ack) for the channel hopping message from the slave, and resumes data transmission / reception through the idle channel after occupying the idle channel.

The master may include a step of performing data retransmission within a predetermined time period if a data transmission failure occurs in a state where the reception failure rate of the detected data acknowledgment signal (AcK) is less than a threshold value 1 set.

The master may perform an idle channel search for a time period during which data retransmission is performed.

The master can assign a priority of channel hopping if two or more idle channels are detected.

The master determines whether or not channel hopping is to be performed on the idle channel by applying a random number having an initial value to the master, whether the channel was the channel on which the channel hopping was performed, whether the channel was the current channel and the adjacent channel, You can assign rankings.

The master can set the threshold value 2 to the state immediately before the communication quality is extremely lowered due to congestion.

The master may transmit a channel hopping message to all slaves connected to the network and then resume data transmission / reception by occupying the idle channel after receiving the channel hopping confirmation message from the entire slave.

The master transmits a channel hopping message to all the slaves connected to the network. If the channel hopping acknowledgment message is not received from any one of the slaves, the master first transmits a channel hopping message to the slave first, After receiving the confirmation message, the idle channel can be occupied and the data transmission / reception can be resumed.

As described above, according to the present invention, when channel interference occurs in data communication of a heterogeneous wireless network, an attempt is made to search for an idle channel and communication is performed, so that the success rate of data transmission / reception increases and real time control performance can be improved.

In addition, the present invention can reduce the influence of interference by other systems while minimizing interference to other systems by using the idle channel, so that safety and reliability can be provided in the operation of the system connected to the wireless network.

1 is a diagram illustrating a connection of a heterogeneous wireless network according to an embodiment of the present invention.
2 is a flowchart illustrating a data communication procedure of a heterogeneous wireless network according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating occupation of an idle channel when channel interference occurs in a heterogeneous wireless network according to an embodiment of the present invention. Referring to FIG.

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.

The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are given the same reference numerals throughout the specification.

In addition, since the components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to those shown in the drawings.

FIG. 1 is a diagram illustrating a connection of a heterogeneous wireless network according to an embodiment of the present invention, and FIG. 2 is a flowchart illustrating a data communication procedure of a heterogeneous wireless network according to an embodiment of the present invention.

1, the present invention comprises one master 100 and a plurality of slaves 200. The data communication between the master 100 and the slave 200 is performed by the data transmission request signal Req (Ack) provided by the slave 200 according to the data acknowledgment signal

The data transmission request signal Req of the master 100 is transmitted in a 1: 1 communication with the slave 200 and the data reception acknowledge signal Ack of the slave 200 is transmitted to the master 100 in a 1: 1 communication or broadcast to another slave.

The payload of ZigBee is divided into a static segment and a dynamic segment for real-time data transmission.

The static segment is used for real-time data transmission between the master 100 and each slave 200, and an operation for channel hopping is performed in a dynamic segment.

In the state where the master 100 and the slave 200 are performing data transmission and reception through the occupied channel, whether the channel is interfered or not is determined based on data provided from the slave 200 according to the data transmission request signal Req of the master 100 It is determined whether or not the acknowledgment signal Ack is received.

When channel interference occurs in a state where data transmission / reception between the master 100 and the slave 200 proceeds, the master 100 searches for another idle channel and hopes for the idle channel searched for.

The master 100 transmits a message for guiding channel hopping to the entire slave 200 and receives a response message for confirming channel hopping from the entire slave 200, The data communication channel between the slaves 200 can be made through the channel occupied by the channel hopping.

Communication between the master 100 and a plurality of slaves 200 will be described in detail with reference to FIG.

The master 100 transmits a request signal Req for data transmission to the slave 200 in the Zigbee network according to the present invention and the slave 200 transmits an acknowledge signal Ack (Step S101).

As described above, a period during which the master 100 and the slave 200 perform periodic data communication is referred to as a static segment, and during the static segment, the master 100 is provided in the slave 200 for a pre- And calculates a reception failure rate of the data reception acknowledgment signal (Ack) (S102).

In step S102, the master 100 determines whether the reception failure rate of the calculated data acknowledgment signal Ack is less than a pre-programmed threshold value 1 (S103).

In step S103, if the data transmission failure occurs in a state where the reception failure rate of the computed data reception acknowledgment signal (Ack) is less than the pre-programmed threshold value 1, the master 100 retransmits the failed data within the pre- , And this interval is called a dynamic segment (S104).

In step S103, the master 100 searches for an idle channel for a maximum allowable dynamic segment time when the reception failure rate of the calculated data acknowledgment signal Ack exceeds the pre-programmed threshold value 1 (S105).

The master 100 assigns priority of channel hopping to two or more idle channels found in step S105 (S106).

The priority assignment of the channel hopping to the idle channel is performed based on whether the channel was the channel on which channel hopping was performed by previous interference, whether the current channel is not adjacent to the current channel, and the unique identification number given to the master 100 It is determined by a random number value.

The reception failure rate is increased in a state where data transmission / reception is performed between the master 100 and the slave 200 by the above operation, and the reception failure rate of the data reception acknowledgment signal Ack calculated by the master 100 is compared with the previously programmed threshold value 2 (S107).

The setting of the threshold value 2 can be set to a state immediately before communication quality is extremely lowered due to congestion.

In step S107, the master 100 stops sending / receiving data to / from the slave 200 when the reception failure rate of the computed data acknowledge signal Ack exceeds the pre-programmed threshold value 2 (step S108) And transmits to the slave 1 200-1 a channel hopping message from the idle channel searched in S106 to the channel allocated in the priority order (S109).

After transmitting the channel hopping message, the master 100 determines whether a channel hopping confirmation message is received from the slave 1 200-1 (S110). If the channel hopping confirmation message is not received, And the channel hopping message is retransmitted to the slave 1 (200-1).

However, if the master 100 receives the channel hopping confirmation message from the slave 1 200-1, the master 100 occupies the corresponding channel.

The channel hopping message transmission of the master 100 is sequentially executed for the N slaves 200-N, and when receiving the channel hopping confirmation message from the N slaves 200-N, the channel hopping message is occupied.

The master 100 and the slave 200 perform data transmission / reception through a channel occupied by channel hopping.

When the slave 200-2 receives a channel hopping confirmation message for the channel hopping message of the slave 200-1, the slave 200-2 also checks the hopping channel and transmits a channel hopping confirmation message to the slave 200-2 And this process is repeated until the slave N (200N) which is the last slave.

When the master 100 transmits a channel hopping message to a plurality of slaves 200 and does not receive a channel hopping confirmation message from a particular slave in the middle when receiving a channel hopping confirmation message from the slave 200, 100 retransmits the channel hopping message to the slave 1 200-1 again so that the entire slave 200-N can receive the channel hopping message.

If the idle channel is occupied by channel hopping between the master 100 and the entire slave 200 through the above-described procedure, real-time data transmission / reception is performed through the occupied channel.

FIG. 3 is a diagram illustrating occupation of an idle channel when channel interference occurs in a heterogeneous wireless network according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 3, when a master and a slave transmit / receive data using channel 11 in a Zigbee network applied to a door system of a vehicle, for example, when interference occurs due to a heterogeneous network such as a mobile phone terminal or a notebook Wi-fi The master of the ZigBee network detects the occurrence of interference in the communication channel, and at the same time, searches for the idle channel No. 13, which does not cause interference, among the available channels 11 to 14.

Then, the master transmits the channel number 13, which is the idle channel, to the other slaves in the network in the channel hopping message. When receiving the channel change acknowledgment message (Ack) from each slave, the master occupies the idle channel 13 And then try to communicate with each slave.

Each slave changes its occupation channel to 13 and sends a confirmation message (Ack) when a message is received from the master. The master confirms a confirmation message (Ack) from all slaves and changes to channel hopping 13 times And resumes transmitting and receiving data through the channel.

Since the channel occupied by the CHILLIP hopping is not occupied by another network, data communication can be continued without interference.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various modifications and changes may be made without departing from the scope of the appended claims.

100: Master 200: Slave

Claims (8)

A master and a slave connected to a wireless network transmit and receive data transmission request signals Req and Ack through an occupied channel;
Detecting a reception failure rate of a data reception acknowledgment signal (AcK) provided in a slave for a predetermined period of time;
Searching for an idle channel if the reception failure rate of the data acknowledgment signal (Ack) exceeds the set threshold value 1;
When the reception failure rate of the data acknowledgment signal (Ack) exceeds the set threshold value 2, the master stops transmitting and receiving data with the slave and transmits a channel hopping message together with the searched idle channel information;
When the acknowledgment signal (Ack) for the channel hopping message is received from the slave, the master occupies the idle channel and resumes data transmission / reception through the idle channel;
The method comprising the steps of: The method according to claim 1,
Wherein the master performs data retransmission within a predetermined time period when a data transmission failure occurs in a state where the reception failure rate of the detected data reception acknowledgment signal (AcK) is less than the threshold value 1 set. 3. The method according to claim 1 or 2,
Wherein the master performs an idle channel search during a time during which data retransmission is performed. The method according to claim 1,
Wherein the master allocates a priority of a channel hopping if two or more idle channels are detected. The method according to claim 1 or 4,
The master determines whether or not channel hopping is to be performed on the idle channel by applying a random number having an initial value to the master, whether the channel was the channel on which the channel hopping was performed, whether the channel was the current channel and the adjacent channel, A method of data communication in a heterogeneous wireless network that assigns a ranking. The method according to claim 1,
Wherein the master sets a threshold value of 2 immediately before the communication quality is extremely reduced due to congestion. The method according to claim 1,
Wherein the master transmits a channel hopping message to all the slaves connected to the network and then resumes the data transmission / reception by occupying the idle channel after receiving the channel hopping confirmation message from the entire slave. 8. The method of claim 1 or 7,
The master transmits a channel hopping message to all the slaves connected to the network. If the channel hopping acknowledgment message is not received from any one of the slaves, the master first transmits a channel hopping message to the slave first, And resumes the data transmission / reception by occupying the idle channel after receiving the confirmation message.

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