KR20130065798A - Wi-fi system in container terminal and wireless connecting method thereof - Google Patents

Abstract

PURPOSE: A Wi-Fi system of a container terminal and a wireless access method thereof are provided to offer seamless wireless communication with a Wi-Fi network provided by the AP (Access Point) of a crane and a lighting tower. CONSTITUTION: A plurality of first AP (22) is installed in a first specific location and is connected to a control center(10). One or more second AP(32) are installed within the assignment area of a specific first AP and form a wireless bridge with the first AP. Terminals(38,40) transmits a job order result for a job order transmitted from the control center by connecting to the first or the second AP. [Reference numerals] (10) Control center; (12) Backbone switch; (14) Job order server; (16) Wireless network management server; (20) Lamp top; (22) Lamp top access point; (24,34) Omnidirectional antenna; (26,36) Ceiling directional antenna; (30) Crane; (32) Crane access point; (38) Crane terminal; (40) Yard truck terminal

Description

Wi-Fi system in container terminal and wireless connecting method

The present invention relates to a Wi-Fi system of a container terminal, and more particularly, to a container terminal that establishes a Wi-Fi network between a crane or a yard truck and improves the reliability of wireless communication between the crane and the yard truck in order to increase the working efficiency of the container port. It relates to a wireless connection method of a terminal using the Wi-Fi system and the Wi-Fi network.

In general, a Wi-Fi network is established in a container terminal to improve work efficiency, and work information is transmitted from a port operation room to a crane operator or a yard truck driver in a container terminal through a Wi-Fi system.

However, the Wi-Fi network of the conventional container terminal has a problem that the reliability and safety of data wireless transmission is not secured due to the characteristics of the container terminal exposed to iron and water.

Therefore, in a general container terminal wireless network, the Wi-Fi network is not used as a primary wireless communication network but as a secondary communication network.

The article on the wireless network environment of the container terminal is published in the Korean Journal of Communication Sciences, Vol. 34, No. 3, entitled "Analysis of Container Networks and Improvement of Service Quality."

When constructing a wired network to build a network infrastructure of a container terminal, there is a problem that the reality is inferior because of enormous cost and time for network construction.

Therefore, the above-described problem occurs when the Wi-Fi network is constructed to build a network infrastructure of a container terminal at low cost.

The Wi-Fi network of the conventional container terminal is generally used to build an IEEE 802.11b wireless network using the 2.4GHz ISM band. An example of the configuration of the Wi-Fi network constructed as described above is shown in FIG. 1, and each access point is installed in a light tower installed in a port.

FIG. 1 is an extract from "Analysis of Container Networks and Improvement of Service Quality" published in the Journal of the Korean Institute of Communication Sciences in March 2009.

Referring to FIG. 1, a yard truck and cranes moving around an information center and a light tower, which are the backbone of a port network, exchange data through a light tower access point.

Each light tower's access point is connected to the information center by an optical cable, and wireless communication using the access point is made only to yard trucks and cranes passing around the light tower.

Each access point is installed every 400m, because the light tower is installed every 400m. In addition, neighboring access points use radio channels 1, 6, and 11, which are channels 1 and 6 that do not cause interference between channels among the allocated channels in the wireless communication using 2.4GHz. Because.

In the above paper, in the current port, the WiFi network in the harbor has a network disconnection and receives signals from access points in other areas because terminals passing around the access point communicate using a remote access point instead of using the nearby access point. It is suggested to have problems. In order to solve this problem, the above paper proposes an 802.11a wireless network using a 5GHz band.

However, if a reliable Wi-Fi network is established at the port, the crane used for the port must be remotely controlled, and the camera image must be transmitted wirelessly for this purpose. The implementation of such a function is not suitable for an 802.11a wireless network.

Accordingly, as described above, the Wi-Fi network of the container terminal, which can smoothly perform data wireless communication, does not occur in high-capacity data communication, and can limit the use of a remote access point, is desired.

The present invention minimizes the shadow generated in a place where obstacles to wireless communication such as a container terminal, thereby providing a wireless communication through the Wi-Fi network by using an access point adjacent to the location where the Wi-Fi network of the container terminal seamlessly An object of the present invention is to provide a method for wirelessly connecting a terminal to the Wi-Fi network.

In addition, the present invention provides a container terminal that can provide wireless communication through the Wi-Fi network by forming a wireless bridge between the light tower access point installed in the light tower of the container terminal and the crane access point located in the jurisdiction of the light tower access point. Another object of the present invention is to provide a Wi-Fi system and a method of wirelessly connecting a terminal to the Wi-Fi network.

The Wi-Fi system of the container terminal according to the present invention includes a control center for managing a Wi-Fi network, providing a job order through the Wi-Fi network, and receiving a job order result for the job order; A plurality of first access points installed at a first specific location designated in its assigned area, the first access points having a first omnidirectional antenna and a first directional antenna and connected to the control center by a dedicated line and forming the Wi-Fi network; At least one second access point installed in the allocation area of the specific first access point, the second access point having a second omnidirectional antenna and a second directing antenna and forming a wireless bridge with the first access point to provide the Wi-Fi network; And a terminal connected to any one of the first access point and the second access point to receive the job order of the control center and to transmit a profit job order result for the job order. The Wi-Fi network may be connected to any one of the first and second directional antennas of the first access point and the second directional antenna of the second access point.

The control center may further include: a backbone switch connected to the plurality of first access points and the dedicated line; A wireless network management server connected to the backbone switch to control the first access point and the second access point to manage the Wi-Fi network; And a job order server that provides a job order to the terminal connected to the Wi-Fi network through the backbone switch and receives a job order result provided through the Wi-Fi network from the terminal.

Here, the wireless network management server of the control center may differently control the power of both the plurality of first access point and at least one second access point included in the Wi-Fi network.

The dedicated line connecting the first access point and the control center may be formed of an optical cable.

In addition, the first access point and the second access point is preferably operated based on the IEEE 802.11n protocol for wireless communication.

The first access point is installed in the light tower and the second access point is installed in the crane, and the first directional antenna of the first access point and the second directional antenna of the second access point have a lower directivity. It can be configured to have.

The first access point and the second access point may form a wireless bridge through wireless communication between the first omnidirectional antenna and the second omnidirectional antenna.

Here, the terminal may include one or more of a crane terminal installed in the crane or a yard truck terminal installed in the yard truck.

The terminal detects a plurality of access points including a first access point or a second access point at its location, and among the plurality of detected access points, the received signal strength and link quality information value are in an optimal state. Select and access the access point, receive the job order through the currently connected access point, perform a process corresponding to the job order, store the job order result, and power up the currently connected access point If the status is good, the job order result is transmitted to the control center through the Wi-Fi network. If the power status of the currently connected access point is poor, the access point is reselected to access the job order result. It can be transmitted to the control center via a Wi-Fi network.

Here, the reselection of the access point may include selecting and accessing the access point in a state in which a reception signal strength and a link quality information value are optimal among the plurality of detected access points.

On the other hand, the Wi-Fi system of the container terminal according to the present invention, a control center for managing a Wi-Fi network, providing a job order through the Wi-Fi network and receives a job order result for the job order; A plurality of light tower access points installed for each light tower and having a first omnidirectional antenna and a first directing antenna directed downward, and connected to the control center by an optical cable and forming the Wi-Fi network; The first omni-directional antenna of the light tower access point and its first device installed on a crane located within a jurisdiction of the light tower access point and having a second omni-directional antenna and a second-directional antenna directed downward; One or more crane access points forming a wireless bridge by wireless communication between two omnidirectional antennas to form the Wi-Fi network; And a yard truck or the crane, connected to the Wi-Fi network through any one of the first directional antenna of the lighting tower access point or the first directional antenna of the crane access point and transferring the job order of the control center. Receiving and transmitting a result of the job order for the job order.

The control center may include a backbone switch connected to the plurality of lighting tower access points and the optical cable; A wireless network management server connected to the backbone switch to control the plurality of lighting tower access points and one or more crane access points forming the Wi-Fi network; And a job order server for providing a job order to the terminal connected to the Wi-Fi network through the backbone switch and receiving a job order result provided through the Wi-Fi network from the terminal.

The wireless network management server of the control center may differently control the powers of the plurality of light tower access points and at least one crane access point included in the Wi-Fi network.

In addition, the lighting tower access point and the crane access point is preferably operated based on the IEEE 802.11n protocol for wireless communication.

The terminal detects a plurality of access points including the lighting tower access point or the crane access point at its location, and among the plurality of detected access points, the received signal strength and the link quality information value are optimal. Select and access the access point, receive the job order through the currently connected access point, perform a process corresponding to the job order, store the job order result, and power up the currently connected access point If the status is good, the job order result is transmitted to the control center through the Wi-Fi network. If the power status of the currently connected access point is poor, the access point is reselected to access the job order result. It can be transmitted to the control center via a Wi-Fi network.

Here, the reselection of the access point may include selecting and accessing the access point in a state in which a reception signal strength and a link quality information value are optimal among the plurality of detected access points.

In addition, the wireless access method of the Wi-Fi system of the container terminal according to the present invention is connected to the control tower that manages the Wi-Fi network and provides a job order by an optical cable to the light tower access point and the light tower access point forming the Wi-Fi network. Wi-Fi forming step of the crane access point located in the allocated area to form a wireless bridge; And a terminal communication step of a terminal accessing the Wi-Fi network to receive the job order and transmitting a job order result corresponding thereto to the control center through the Wi-Fi network, wherein the terminal communication step includes: Detecting a plurality of access points including the lighting tower access point or the crane access point corresponding to the Wi-Fi network to which the network belongs; Selecting and accessing the access point having a best reception signal strength and link quality information value among a plurality of detected access points; Receiving the job order through the currently connected access point and performing a process corresponding to the job order and storing the job order result; Transmitting the job order result to the control center through the Wi-Fi network if the power state of the currently connected access point is good; And re-selecting the access point and transmitting the job order result to the control center via the Wi-Fi network if the power state of the currently connected access point is poor.

Accordingly, according to the present invention, a crane, which is a first access point connected to a control center at a place such as a container terminal in which an obstacle to wireless communication exists, and a second access point forming a wireless bridge with the light tower access point There is an effect that the wireless communication can be provided seamlessly by the Wi-Fi network provided by the access point.

In addition, a terminal installed in a crane or a yard truck through the Wi-Fi network may seamlessly perform wireless communication using an adjacent access point.

1 is a view taken from the "wireless network analysis and service quality improvement method of the container terminal" published March 2009 in the Journal of the Korean Institute of Communication Sciences.
Figure 2 is a block diagram showing a preferred embodiment of a wireless network system of a container terminal according to the present invention.
FIG. 3 is a flowchart for explaining radio communication operations performed in the crane terminal and the yard truck terminal of FIG. 2. FIG.
4 is a flowchart for explaining a method of selecting an access point for wireless communication among a plurality of detected access points.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments are provided to those skilled in the art to fully understand the present invention, and may be modified in various forms, and the scope of the present invention is limited to the embodiments described below. It doesn't happen.

The Wi-Fi system of the container terminal according to the present invention is implemented as shown in Figure 2 to provide a Wi-Fi network.

2, an embodiment of a Wi-Fi system of a container terminal according to the present invention is a control center 10, a light tower access point 22 installed in a light tower 20, a crane access point 32 installed in a crane 30. And a terminal.

Here, the terminal may include a crane terminal 38 installed on the crane 30 operated in the container terminal and a yard truck terminal 40 installed on the yard truck operated for the yard.

The control center 10 has a function of managing a Wi-Fi network, providing a job order through the Wi-Fi network, and receiving a job order result for the job order.

In order to perform the above-described functions, the control center 10 is connected to the backbone switch 12 and the backbone switch 12 connected to the plurality of light tower access points 22 and the optical cable, and the plurality of light tower access points to form a Wi-Fi network. The wireless network management server 16 controlling the 22 and one or more crane access points 32, and the backbone switch 12 provides a job order to a terminal connected to the Wi-Fi network and the Wi-Fi network at the terminal. And a job order server 14 for receiving the result of the job order.

Here, the wireless network management server 16 controls the network equipment to provide efficient network service through continuous observation of the network equipment including the light tower access point 22 and the crane access point 32 forming the Wi-Fi network. To conduct forecasting and analysis.

The job order server 14 is a server that transmits a work instruction to a yard truck or a crane 30 in which a terminal in a container terminal is installed through a Wi-Fi network, and performs a process for obtaining a result corresponding to the work instruction.

The control center 10 and the plurality of lighting tower access points 22 described above are connected by forming a dedicated line with an optical cable for bidirectional communication.

In addition, the lighting tower access point 22 includes a non-directional antenna 24 and a ceiling-oriented antenna 26 to form a Wi-Fi network.

In addition, a crane access point 32 is installed in a crane 30 located in a jurisdiction of the light tower access point 22, and the crane access point 32 also includes an omnidirectional antenna 34 and a ceiling-oriented antenna 36. Has the ability to form a WiFi network.

The lighting tower access point 22 and the crane access point 32 are provided with two types of antennas, respectively, the omnidirectional antennas 24 and 34 and the ceiling-oriented antennas 26 and 36.

Among them, the ceiling-oriented antenna 6 has a function of directing its lower side (bottom), and the ceiling-oriented antenna 6 is configured such that a yard truck, which is a communication object operated at a container terminal, is lower than a crane 30 in general. Because it is in position.

In addition, the omnidirectional antennas 24 and 34 are omni-antenas to communicate with each other omnidirectionally, whereby the light tower access point 22 and the crane access point 32 are wireless bridged. Can be formed. That is, the omnidirectional antennas 24 and 34 are used for wireless communication between the light tower access point 22 and the crane access point 32.

In addition, the lighting tower access point 22 and the crane access point 32 forming the Wi-Fi network are preferably configured to operate based on the IEEE 802.11n protocol to perform wireless communication capable of remote control and remote image communication.

IEEE 802.11n is a wireless LAN standard that supports speeds up to 600 Mbps with multiple input multiple output (MIMO) technology using multiple antennas and variations of the MAC and physical layers to minimize bandwidth loss. Orthogonal Frequency Division Multiplexing (OFDM) and multiplexed preliminary configurations improve reliability, and are resistant to ambient interference, and operate in a wider area wireless LAN that handles high bandwidth video such as multiple high definition television (HDTV) and digital video streaming. can do.

In addition, the above-described lighting tower access point 22 may be provided in the lighting tower 20 installed at a predetermined distance of the container terminal to provide a Wi-Fi network for its own jurisdiction. That is, it can perform wireless communication with the yard truck terminal 40 located in its jurisdiction.

According to the embodiment of the present invention, since the above-described lighting tower access point 22 alone is difficult to minimize the shadow area of the entire container terminal, the crane access point for relaying wireless communication to the crane 30 installed and operated in the container terminal. 32 is installed to minimize the shaded area.

That is, since the crane access point 32 forms a wireless bridge with the light tower access point 22 to provide a Wi-Fi network, the crane terminal 38 installed in the crane 30 or the yard truck terminal 40 adjacent to the wireless device is wirelessly connected. Communication can be carried out, and thus the Wi-Fi communication space in the container terminal can be secured widely, so that the shadow area can be minimized.

The wireless network management server 16 of the control center 10 of the configuration according to the present invention described above is a wireless communication of a plurality of light tower access point 22 and one or more crane access point 32 forming a Wi-Fi network on a container terminal. Adjust the signal strength, or power, differently.

In addition, the wireless network management server 16 of the control center 10 manages the power of the plurality of lighting tower access point 22 and one or more crane access point 32 does not exceed 60dBm.

If the power of the access points 22 and 32 is too strong, a phenomenon occurs in which the yard truck terminal 40 or the crane terminal 38 is connected to a remote access point without connecting to an access point adjacent to the wireless communication. A break occurs frequently.

The wireless network management server 16 of the control center 10 preferably controls the power of the light tower access point 22 and the crane access point 32 as described above in order to suppress the above-mentioned phenomenon.

As described above, the wireless connection of the terminal may be made as shown in FIG. 3 by the Wi-Fi system of the container terminal according to the present invention configured as shown in FIG. 2.

First, the Wi-Fi network is managed by a control center 10 that provides job orders, and crane access located in an area allocated to the light tower access point 22 and the light tower access point 22 connected to the control center 10 by an optical cable. Point 32 forms a wireless bridge to form a Wi-Fi network.

As described above, the terminal including the crane terminal 38 or the yard truck terminal 40 (hereinafter, referred to as a “terminal”) in the state where the Wi-Fi network is formed performs a wireless connection by performing the sequential process of FIG. 3. .

The terminal detects a plurality of access points by scanning an access point that can be detected at its location (S10). Herein, the access point selects an access point to which the user should access from among the access points detected at his location, and the access point to which he / she accesses may include a light tower access point 22 or a crane access point 32. .

At this time, the selection of the access point to be connected to itself can be determined by SSID (Service Set IDentifier: hereinafter, unique identification code). Typically, access points included in the same Wi-Fi network include a common SSID. Therefore, as the SSID, the terminal filters out access points not belonging to the Wi-Fi network to be used and detects a plurality of access points having SSIDs belonging to the Wi-Fi network to be used.

When the terminal determines that a plurality of access points are detected according to the scan (S12), the terminal selects the access point to which the terminal accesses (S14).

In this case, the terminal detects the received signal strength and the link quality information value of the signal transmitted from the access point, respectively, and selects and accesses the optimal access point. A method for selecting an access point will be described later with reference to FIG. 4.

On the other hand, if there is no access point to select in the selection process, the terminal performs the above-described process of scanning and detecting the access point and if there is an access point to select (S16), accesses the selected access point (S20).

As described above, the terminal receives the job order transmitted through the Wi-Fi network from the job order server 14 of the control center 10 and performs a process corresponding to the job order, and then performs the job order. The result is stored (S22).

If it is determined that the selected access point is good, the terminal transmits the job order result to the job order server 14 through the currently selected access point (S26).

If the selected access point is in a poor communication state (S24), the access point can be used without re-selection by reconnection (S28), and the job order result is re-selected through the Wi-Fi network through the selected access point. (S26).

In this case, the access point reselection of the terminal may include selecting and accessing the access point having the optimal reception signal strength and link quality information value among the plurality of detected access points in steps S14 and S16. It can be performed, including.

Meanwhile, as described above, selecting an access point to be connected from among a plurality of access points detected by the terminal in step S10 (S14) may be performed in the procedure of FIG. 4.

That is, after receiving a plurality of access point signals (S30), the received signal strength (RSSI: Recived Signal Strength Indicator) of each signal is detected (S32) and the link quality information value (LQI: Link Quality Indicator) at each strength value In step S34, an access point having the best link quality information value is selected as the received signal strength and the link quality information value with the received signal strength of 60 dBm or less (S36).

Here, the received signal strength represents the strength of the radio signal received from the other party equipment. The received signal strength may vary depending on the distance or power of the other device.

And, the link quality information value means the quality of the connected communication state, and even though the strength of the radio signal is strong, the quality may not be good due to the influence of the surrounding environment. The link quality information value typically indicates a bit error rate (BER) as an integer value between 0 and 255. The higher the value, the better the communication quality.

An embodiment according to the present invention selects an access point having a wireless signal strength of 60 dBm or less, which is more likely to occur when the strength of the wireless signal is too high. The purpose is to select the access point and also to select the neighboring access point by filtering that the strength of the radio signal is strong at a long distance.

As described above, the terminal selects an access point to access by referring to the strength of the received signal and the link quality information value. Since it can be filtered by the link quality information value, it is possible to obtain a result of selecting an access point adjacent to itself.

Therefore, in the case of the container terminal, since many steel structures are constructed, scattering may occur due to the characteristics of the Wi-Fi frequency itself. As a result, a signal of a strong state may be transmitted to another area beyond the jurisdiction of the access point, and thus, the terminal may be connected to a remote access point. Such an error may be filtered by the method of FIG. .

As described above, the lighting tower access point, which is the first access point connected to the control center at a place such as a container terminal in which an obstacle to wireless communication exists, forms a wireless bridge with the lighting tower access point. 2 There is an effect that the wireless communication can be provided seamlessly by the Wi-Fi network provided by the crane access point, which is an access point.

In addition, a terminal installed on a crane or a yard truck through the Wi-Fi network may perform wireless communication smoothly using an access point adjacent to the Wi-Fi network.

10 control center 12 backbone switch
14: Job Order Server 16: Wireless Network Management Server
20: light tower 22: light tower access point
24: omnidirectional antenna 26: ceiling-oriented antenna
30: crane 32: crane access point
34: omnidirectional antenna 36: ceiling-oriented antenna
38: crane terminal 40: yard truck terminal

Claims (18)

A control center managing a Wi-Fi network, providing a job order through the Wi-Fi network, and receiving a job order result for the job order;
A plurality of first access points installed at a first specific location designated in its assigned area, the first access points having a first omnidirectional antenna and a first directional antenna and connected to the control center by a dedicated line and forming the Wi-Fi network;
At least one second access point installed in the allocation area of the specific first access point, the second access point having a second omnidirectional antenna and a second directing antenna and forming a wireless bridge with the first access point to provide the Wi-Fi network; And
And a terminal connected to any one of the first access point and the second access point to receive the job order of the control center and to transmit a profit job order result for the job order.
And the terminal is connected to the Wi-Fi network through either the first directional antenna of the first access point or the second directional antenna of the second access point.
The method of claim 1, wherein the control center,
A backbone switch connected to the plurality of first access points and the dedicated line;
A wireless network management server connected to the backbone switch to control the first access point and the second access point to manage the Wi-Fi network; And
And a job order server that provides a job order to the terminal connected to the Wi-Fi network through the backbone switch and receives a job order result provided through the Wi-Fi network from the terminal.
The Wi-Fi system of claim 2, wherein the wireless network management server of the control center controls the powers of the plurality of first access points and one or more second access points differently included in the Wi-Fi network. .
The Wi-Fi system of claim 1, wherein the dedicated line connecting the first access point and the control center is formed of an optical cable.
The Wi-Fi system of claim 1, wherein the first access point and the second access point operate based on an IEEE 802.11n protocol for wireless communication.
The method according to claim 1,
The first access point is installed in the light tower and the second access point is installed in the crane, the first directional antenna of the first access point and the second directional antenna of the second access point is to have a lower directivity WIFI system of container terminals being configured.
The method according to claim 1,
And the first access point and the second access point form a wireless bridge through wireless communication between the first omnidirectional antenna and the second omnidirectional antenna.
The method according to claim 1,
The terminal is a Wi-Fi system of the container terminal including at least one of the crane terminal is installed on the crane or the yard truck terminal is installed on the yard truck.
The method of claim 1, wherein the terminal,
Detect a plurality of access points including a first access point or a second access point corresponding to the Wi-Fi network to which the user belongs to
Selecting and accessing the access point having the optimal reception signal strength and link quality information value among the plurality of detected access points,
Receiving the job order through the currently connected access point and performing a process corresponding to the job order, and storing the job order result;
If the power state of the currently connected access point is good, the job order result is transmitted to the control center through the Wi-Fi network, and
If the power state of the currently connected access point is poor, the Wi-Fi system of the container terminal to re-select the access point to connect and transmit the job order results to the control center via the Wi-Fi network.
10. The method of claim 9,
The reselection of the access point is a Wi-Fi system of a container terminal comprising selecting and accessing the access point of a state in which a reception signal strength and a link quality information value are optimal among a plurality of detected access points.
A control center managing a Wi-Fi network, providing a job order through the Wi-Fi network, and receiving a job order result for the job order;
A plurality of light tower access points installed for each light tower and having a first omnidirectional antenna and a first directing antenna directed downward, and connected to the control center by an optical cable and forming the Wi-Fi network;
The first omni-directional antenna of the light tower access point and its first device installed on a crane located within a jurisdiction of the light tower access point and having a second omni-directional antenna and a second-directional antenna directed downward; One or more crane access points forming a wireless bridge by wireless communication between two omnidirectional antennas to form the Wi-Fi network; And
Installed in a yard truck or crane and connected to the Wi-Fi network through either the first directional antenna of the lighting tower access point or the first directional antenna of the crane access point and receiving the job order of the control center And a terminal for transmitting the job order result for the job order.
The method of claim 11, wherein the control center,
A backbone switch connected to the plurality of lighting tower access points and the optical cable;
A wireless network management server connected to the backbone switch to control the plurality of lighting tower access points and one or more crane access points forming the Wi-Fi network; And
And a job order server that provides a job order to the terminal connected to the Wi-Fi network through the backbone switch and receives a job order result provided through the Wi-Fi network from the terminal.
The Wi-Fi system of claim 12, wherein the wireless network management server of the control center differently adjusts power of the plurality of light tower access points and at least one crane access point included in the Wi-Fi network.
12. The Wi-Fi system of claim 11, wherein the light tower access point and the crane access point are operated based on IEEE 802.11n protocol for wireless communication.
The method of claim 11, wherein the terminal,
Detect a plurality of access points including the light tower access point or the crane access point corresponding to the Wi-Fi network to which they belong at their location,
Selecting and accessing the access point having the optimal reception signal strength and link quality information value among the plurality of detected access points,
Receiving the job order through the currently connected access point and performing a process corresponding to the job order, and storing the job order result;
If the power state of the currently connected access point is good, the job order result is transmitted to the control center through the Wi-Fi network, and
If the power state of the currently connected access point is poor, the Wi-Fi system of the container terminal to re-select the access point to connect and transmit the job order results to the control center via the Wi-Fi network.
The method of claim 15,
The reselection of the access point is a Wi-Fi system of a container terminal comprising selecting and accessing the access point of a state in which a reception signal strength and a link quality information value are optimal among a plurality of detected access points.
A Wi-Fi forming step of managing a Wi-Fi network and an optical tower connected to a control center providing a job order by an optical cable to form a wireless bridge between a light tower access point forming the Wi-Fi network and a crane access point located in an area allocated to the light tower access point; And
After the terminal is connected to the Wi-Fi network receives the job order and the terminal communication step of transmitting a corresponding job order result to the control center via the Wi-Fi network,
The terminal communication step,
Detecting a plurality of access points including the light tower access point or the crane access point corresponding to the Wi-Fi network to which the user belongs at the location thereof;
Selecting and accessing the access point having a best reception signal strength and link quality information value among a plurality of detected access points;
Receiving the job order through the currently connected access point and performing a process corresponding to the job order and storing the job order result;
Transmitting the job order result to the control center through the Wi-Fi network if the power state of the currently connected access point is good; And
And re-selecting the access point and transmitting the job order result to the control center via the Wi-Fi network if the power state of the currently connected access point is poor. Wireless connection method of the system.
The method of claim 17,
Reselecting the access point includes selecting and accessing the access point having a best reception signal strength and a link quality information value among the plurality of detected access points. .

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