KR102010362B1 - HIGH SPEED HAND-OFF METHOD FOR GUARANTEEING MOBILITY OF DENSE WiFi SMALL CELL NETWORK - Google Patents

Abstract

The present invention relates to a handoff method and, more specifically, to a high-speed handoff method for guaranteeing mobility of a dense Wi-Fi small cell network, capable of guaranteeing excellent micro mobility by enabling fast and accurate handoff between Wi-Fi small cells when a user terminal moves frequently in a Wi-Fi cell environment which is smaller than the existing network as a Wi-Fi cell is gradually reduced in size and a dense small cell network and a single independent network structure are also gradually spread, in order to efficiently process data traffic which is rapidly accelerated using high frequency and mmWave in Wi-Fi. To this end, the handoff method comprises: a Wi-Fi access point (AP) having only two layers of a physical layer and a data link layer in an open system interconnection 7 layer (OSI 7 layer); a Wi-Fi AP line concentration device having three or more layers of the physical layer, the data link layer, and a network layer and connected to at least one Wi-Fi AP in two layers; and an IP data line concentration device for allocating an Internet protocol (IP) while managing the Wi-Fi AP and the Wi-Fi AP line concentration device, connected to an external network, and transferring IP data to the Wi-Fi AP through a Wi-Fi line concentration device.

Description

HIGH SPEED HAND-OFF METHOD FOR GUARANTEEING MOBILITY OF DENSE WiFi SMALL CELL NETWORK}

The present invention relates to a handoff method, and more specifically, a compact small cell network and a single independent network as the cells of WiFi gradually become smaller for efficient processing of data traffic that is rapidly speeded up by using high frequency and mmWave in WiFi. As the structure is also spreading, the mobility of dense WiFi small cell networks can be ensured by enabling fast and accurate handoff between WiFi small cells during frequent movements of user terminals in a smaller WiFi cell environment. To a fast handoff method.

In general, a handoff in a wireless LAN (WiFi) causes instantaneous data loss due to hard handoff between APs.

In particular, user terminals in a WLAN environment are assigned an IP address from an AP or a higher level device. In the IP layer, packets are routed according to the subnet prefix of a destination address. Therefore, if a terminal moves to another subnet, Whenever a network is moved, it must be changed to an IP address having a network prefix of the network. In this case, continuous communication is impossible because higher layer connections such as TCP connections are not guaranteed.

Therefore, in order to enable communication while maintaining the existing address, a three-layer protocol called Mobile IP, which can guarantee mobility, must be used, and since the wireless LAN is designed without considering compensation for data loss, higher application services are required. Cannot support real-time services.

In the case of WLAN, basically, without proper support for Layer 2, efficient handoff cannot be provided. Therefore, as mentioned above, handoff in WLAN currently supports Layer 3 handoff using Mobile IP. have.

However, the conventional Mobile IP defines the handoff of the third layer irrespective of the technology of the lower two layers, and does not consider a handoff that supports real-time handoff and inter-cell mobility (micro mobility).

As mentioned above, in the existing WiFi device, as most terminals are assigned a unique IP from the WiFi device or from the upper network, as shown in FIG. 1, packets are routed according to destination addresses in the IP layer. If you want to continue the communication even if you move to the WiFi AP, whenever you move the wireless service interval of the WiFi AP, you have to change to the IP address having the network prefix of the wireless network or use a separate complicated three-layer protocol called Mobile IP.

As such, in the existing WiFi AP, when the user terminal moves, the problem of having to go through three layers for routing may be a factor causing delay in a high-speed network such as 5G. As in the roaming method, high-speed handoff is impossible due to a delay caused by IP exchange when the user terminal moves in the current WiFi device.

Therefore, in the current wireless network environment where small cells and pico cells are increasing for high speed Wi-Fi service, or in an island-type island network such as a smart city, a handoff design at the second layer that supports mobility between Wi-Fi cells is not possible. Because it needs to be considered, a study on this is needed.

Republic of Korea Patent Publication No. 10-1531189 Republic of Korea Patent Publication No. 10-0933760

The present invention has been made to solve the above problems of the prior art, unlike the existing devices in a high-density high-speed small cell environment by separating the function of the WiFi device to enable high-speed handoff of the mobile communication class To ensure the mobility of the dense WiFi small cell network that can enable seamless data service despite the change of the service cell size due to the explosion of users during the movement by determining the high-speed service cell in the cell overlapping section where handoff occurs. It is an object of the present invention to provide a fast handoff method.

In order to achieve the above object, the present invention provides a WiFi Access Point (AP) having only two layers of a physical layer and a data link layer in an OSI 7 layer (Open System Interconnection 7 Layer); A WiFi AP concentrator having three or more layers of a physical layer, a data link layer, and a network layer and connected to at least one or more of the WiFi APs in a second layer; And an IP data concentrator that manages the WiFi AP and the WiFi AP concentrator, allocates an IP (Internet Protocol), and is connected to an external network to transfer IP data to the WiFi AP through the WiFi concentrator.

Here, the WiFi AP which is providing data service to the user terminal through the connected external network requests the WiFi AP concentrator to release a MAC (Media Access Control) address of the moving user terminal, and the new WiFi AP connected to the user terminal is WiFi Only the MAC address of the user terminal is registered in the AP concentrator so that handoff is performed without an IP exchange when the user terminal moves between cells.

On the other hand, the present invention, MAC release request step of requesting the release of the user terminal MAC address to the WiFi AP concentrator when the received electric field strength of the user terminal is not detected in the WiFi A; A MAC release step of the WiFi AP concentrator releasing a self-registered user terminal MAC address in response to a user terminal MAC address release request; A new MAC registration request step of requesting the WiFi AP concentrator to register a new MAC address of the user terminal when the WiFi AP concentrator scans and receives the received electric field strength of the user terminal from another WiFi AP; And a new MAC address registering step of registering, by the WiFi AP concentrator, a new MAC address of the user terminal.

Further, in the MAC release request step, the WiFi AP concentrator transmits an ACK (Acknowledge) message for receiving the MAC address release request to the WiFi AP, and in the MAC release step, the WiFi AP concentrator sends the MAC address release complete ACK message to the WiFi AP. After transmitting to the AP, the WiFi AP re-confirms the user terminal and transmits a release final completion ACK message to the WiFi AP concentrator.In the request for registering a new MAC, the WiFi AP concentrator sends another ACK message for receiving a new MAC address registration request. In the new MAC registration step, the WiFi AP concentrator transmits an ACK message for completing the registration of a new MAC address to another WiFi AP, and another WiFi AP sends an ACK message for starting service of a newly registered user terminal. Characterized in that the transmission to the WiFi AP concentrator.

In addition, in the WiFi cell overlapping section, an overlapping section cell determining step of determining a service cell of the user terminal through a change amount of the hysteresis curve with respect to the direction in which the user terminal moves in the cell and the electric field strength of the user terminal received by the WiFi AP is further included. It is characterized by including.

In the step of determining the overlap section cell, the area of the cell overlap section is calculated as the area of the hysteresis curve based on the x-axis (movement direction between cells) and the y-axis (field strength strength of the user terminal received by the WiFi AP). By setting the field strength tracking value and the field strength change amount to determine the service cell.

In addition, when the user terminal moves from the WiFi AP to another WiFi AP in the WiFi cell boundary and overlapping interval, the priority cell determination step of determining a priority cell for serving the user terminal; And after the priority cell is determined, performing a MAC address registration and release according to the handoff process.

In the determining of the priority cell, the tracking change interval and the service cell determination may be performed according to a predefined hysteresis curve corresponding to a preset level in order to track the received electric field strength of the user terminal.

In the determining of the priority cell, the electric field strength of the user terminal and the location of the intersection of the service start / stop level and the tracking change reduction interval, which are preset by the WiFi AP in the overlapping interval of the WiFi AP and the other WiFi APs, are determined. If the electric field strength is detected to be the same, the user terminal periodically tracks the electric field strength received from the WiFi AP, and checks whether the electric field strength is reduced through tracking, and then overlaps the electric field strength and the tracking change reduction interval crossing position after a certain time (④ point Stopping the user terminal service and requesting the WiFi AP concentrator to release the MAC address of the user terminal when the electric field strength decreases; If the other WiFi AP detects that the electric field strength of the position where the overlapping section electric field strength and the tracking change increase section intersect (① point) is the same, the user terminal periodically tracks the electric field strength received from another WiFi AP. If the field strength increases to a position where the preset service start / stop level and the tracking change increase interval cross (a point ②) after a predetermined time, the other WiFi AP starts the user terminal service. And a service registration step of requesting the WiFi AP concentrator to register the MAC address of the user terminal.

Additionally, the MAC address processing step may include: a tracking level setting request step of requesting, by the WiFi AP and another WiFi AP, a field strength tracking level setting for field strength tracking of a cell overlap region of a user terminal in advance to a WiFi AP concentrator; The WiFi AP concentrator notifies the WiFi AP of the tracking start level setting value of the point ③ and the tracking end level setting value of the point ④, and the WiFi tracking point level setting value of the point and the tracking end level setting value of the point are different from each other. A tracking level setting step of notifying the AP; Stopping the service; A service termination step of confirming whether the MAC address of the user terminal is released after the WiFi AP is notified that the MAC address of the user terminal registered in the WiFi AP concentrator is released, and finally terminating the user terminal service; Registering the service; A service start step of receiving another WiFi AP notifying that the MAC address of the user terminal is newly registered in the WiFi AP concentrator and confirming whether the WiFi AP has registered the MAC address of the user terminal, and finally starting the user terminal service; It is characterized by.

Here, in the tracking level setting request step, the WiFi AP concentrator transmits an ACK message for receiving the field strength tracking level setting request to each of the WiFi AP and the other WiFi AP, and in the tracking level setting step, the WiFi AP and the other WiFi AP After setting the self-reported level setting value and transmits an ACK message to the WiFi AP concentrator, and in the step of stopping the service, the WiFi AP concentrator transmits an ACK message for the MAC address release request of the user terminal to the WiFi AP. In the service termination step, the WiFi AP transmits an ACK message for the MAC address release to the WiFi AP concentrator, and in the service registration step, the WiFi AP concentrator transmits an ACK message for the MAC address registration request of the user terminal to another WiFi AP. In the service initiation step, another WiFi AP transmits an ACK message for registering a MAC address to the WiFi AP concentrator. It is characterized by.

As described above, the high-speed handoff method for guaranteeing mobility of a dense WiFi small cell network according to the present invention reduces the delay time by inter-cell handoff without passing through three layers, thereby providing a seamless high-speed service for real-time services such as IPTV. Handoff is possible.

In addition, the effects and advantages that can be obtained when the network configuration of the functional separation type WiFi device of the present invention instead of the existing WiFi device is shown in Table 1 below.

Item Legacy WiFi Detachable WiFi Mobility method roaming Handoff Hierarchy level Layer 3-Network Layer Layer 2-Data Link Layer
Share between operators Interworking with other domestic and overseas network operators and internal networks is essential to support mobility Independent cell mobility support
No interworking with other network operators Control exchange location IP switch of internal or other network operator 2-layer link concentrator Mobility method IP routing Device MAC address
Mobility delay Delay occurs when interworking with high-traffic network through IP routing Cell-based independent mobility support for 5G low latency networks Judgment Roaming Request Signaling and IP Exchange MAC address location and field strength cost Additional costs incurred by using third party networks No additional costs due to independent cell-to-cell support

Network operation -The exchange of control rights at the mobile switching center as a share between network facilities of other companies.
-Independent network operation is impossible because agreement is required between other network operators -Exchange of control rights between WiFi base stations as sharing between company's network facilities at 2 tier level
-Independent network operation with mobility control

In addition, although WiFi APs provide high capacity of Gbps, the quality of streaming video is difficult to guarantee due to the nature of WiFi channel access sharing channels, short coverage may cause quality degradation or service interruption even at low speed, and there is a limit to guarantee mobility. In this regard, the WiFi service providers need a way to maintain the minimum quality and service even in a congested and mobile situation, and can be provided with a satisfactory data service on the go through the separate small WiFi base station as in the present invention. Related details are as follows.

1. In accordance with the WiFi system of the present invention, due to the reduction of functions, the target APs are smaller and efficient handoff is possible even in a mobile environment of frequent UEs between WiFi small cells in a dense environment.

2. Simple and better connection even in densely populated environment by allowing the active cell to be determined according to the overlap area and user service by following the change of hysteresis curve in the handoff period according to the change of the service cell size due to the rapid increase in capacity. Can be guaranteed.

3. There is a limit to the real-time service due to the latency problem in the routing process according to the wireless relay when the Multi-Wireless AP of the existing mesh type is constructed. However, when the Multi-WiFi AP network is configured according to the present invention, the inter-cell movement is performed. It can be serviced in the middle and minimized shadow area without delay can provide better connection stability.

4. By providing an environment capable of performing handoff between dense radio cells in the L2 layer, a large number of terminals can be provided with a data service that guarantees better seamless connectivity.

1 is a diagram illustrating an operation method when a terminal moves in a conventional WiFi device;
2 is a diagram illustrating a handoff scheme in an L2 layer through WiFi function separation according to the present invention.
3 is a diagram schematically illustrating a configuration of a fast handoff system for ensuring mobility of a dense WiFi small cell network according to the present invention.
4 is a diagram illustrating a general MAC registration and release procedure when moving between WiFi cells according to the present invention.
5 is a diagram illustrating a service cell determination method based on a hysteresis curve in a WiFi cell overlapping period according to the present invention.
6 is a diagram illustrating a handoff procedure after determining cell priority in an overlapping section according to the present invention.

The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention, and do not represent all of the technical idea of the present invention, which can be replaced at the time of the present application It should be understood that there may be various equivalents and variations.

Hereinafter, a high speed handoff system and method for guaranteeing mobility of a dense WiFi small cell network according to the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a diagram illustrating a handoff scheme at an L2 layer through separation of WiFi functions according to the present invention, and FIG. 3 schematically illustrates a high speed handoff system configuration for ensuring mobility of a dense WiFi small cell network according to the present invention. The figure is shown.

The fast handoff system for guaranteeing mobility of a dense WiFi small cell network according to the present invention basically includes a WiFi access point (AP), a WiFi AP concentrator, and an IP data concentrator.

More specifically, the present invention includes a WiFi AP having only two layers of a physical layer and a data link layer in an OSI 7 layer, and three or more layers of a physical layer, a data link layer, and a network layer. A WiFi AP concentrator connected to at least one WiFi AP in a second layer, an IP (Internet Protocol) while managing the WiFi AP and the WiFi AP concentrator, connected to an external network, and connected to an external network through the WiFi concentrator to the IP data. It includes an IP data concentrator for transmitting the.

In the system of the present invention, the WiFi AP which is serving data to the user terminal through the connected external network requests the WiFi AP concentrator to release a MAC (Media Access Control) address of the moving user terminal (UE, UE1, UE2). The new WiFi AP connected to the terminal registers only the MAC address of the user terminal in the WiFi AP concentrator so that handoff is performed without IP exchange when the user terminal moves between cells.

In this regard, referring to FIG. 2, the WiFi AP is limited to two-layer devices having only a physical layer and a data link layer, unlike conventional devices, and is limited to two-layer aggregation of multiple WiFi APs composed only of two layers. To separate the two-layer link aggregation WiFi AP concentrator to separate, and to control the WiFi AP concentrator and WiFi AP, and aggregate the data to connect to the upper network, the three-layer or more IP data concentrator is also separated.

In other words, the system is divided into three functional units in the existing WiFi AP, and its role is as follows.

1. The WiFi AP function provides functionality to Layer 2 devices including only a physical layer and a data link layer in the OSI 7 layer.

2. The WiFi AP concentrator transmits data to a higher layer device by assigning a function to a three-layer device including a physical layer, a data link layer, and a network layer, and connecting a plurality of WiFi APs to a second layer.

3. IP data concentrator manages and controls WiFi APs and WiFi AP concentrators, assigns IPs and connects with external networks to deliver IP data. Three or more layers of OSI layer 7 (network layer, transport layer) , Session layer, presentation layer, application layer).

Referring to FIG. 3, since the WiFi AP, the WiFi AP concentrator, and the IP data concentrator are configured in separate forms, handoff is possible in the MAC layer, which is the second layer, without going through the three layers, and moves between the cells of the terminal. High-speed handoff is possible without IP exchange, that is, the WiFi AP device providing service when the user terminal moves to request the WiFi AP concentrator to release the MAC address of the terminal. If only the MAC address of the terminal is registered in the port, it is performed at high speed without performing an IP exchange in a handoff procedure between adjacent cells.

In particular, in the present invention, as described in detail below, high-speed "Soft micro mobility" is realized through a fast service cell determination method in an overlapping section using a handoff and hysteresis curve in the second layer.

4 is a diagram illustrating a general MAC registration and release procedure when moving between WiFi cells according to the present invention.

The fast handoff method for guaranteeing mobility of a dense WiFi small cell network according to the present invention basically includes a MAC release request step, a MAC release step, a new MAC registration request step, and a MAC address registration step.

More specifically, the present invention is a release request step of requesting the release of the user terminal MAC address to the WiFi AP concentrator when the WiFi AP (WiFi AP1) does not detect the received electric field strength of the user terminal, WiFi The release step of the AP concentrator releases the self-registered user terminal MAC address in response to the request for the release of the user terminal MAC address, and the receiving field strength of the user terminal is detected by another WiFi AP (WiFi AP2) by the WiFi AP concentrator. When the new MAC address registration request to the WiFi AP concentrator to register the new MAC address of the user terminal, and a new MAC address registration step of registering the new MAC address of the user terminal WiFi AP concentrator.

Here, in the MAC release request step, the WiFi AP concentrator transmits an ACK (Acknowledge) message for receiving the MAC address release request to the WiFi AP (WiFi AP1), and in the MAC release step, the WiFi AP concentrator finishes the MAC address release ACK. Sends a message to the WiFi AP (WiFi AP1), the WiFi AP (WiFi AP1) re-checks the user terminal and sends a release final completion ACK message to the WiFi AP concentrator, and in the request for new MAC registration, the WiFi AP concentrator is a new MAC address An ACK message for receiving a registration request is transmitted to another WiFi AP (WiFi AP2) .In the new MAC registration step, the WiFi AP concentrator sends an ACK message for completing registration of a new MAC address to another WiFi AP (WiFi AP2). The WiFi AP (WiFi AP2) transmits an ACK message for the service start of the newly registered user terminal to the WiFi AP concentrator.

Referring to FIG. 4, if the reception power field strength of the user terminal UE1 is not detected by the WiFi AP1, the UE AP releases a MAC address from the WiFi AP concentrator. The WiFi AP concentrator sends an ACK message for the request and releases the MAC address of the UE1 registered in Port1 of the WiFi AP concentrator.

At this time, the WiFi AP concentrator sends the WiFi AP (WiFi AP1) that the MAC address has been released, and the WiFi AP (WiFi AP1) once again checks the state of the UE (UE1) and sends an ACK message to the WiFi AP concentrator.

When the WiFi AP concentrator confirms that the above process is completed, the port AP scans whether there is no new MAC registration request, and in this process, another WiFi AP (WiFi AP2) confirms that the received power field strength of the UE1 is detected. The other WiFi AP (WiFi AP2) requests the WiFi AP concentrator to detect the user terminal (UE1) MAC address and register the user terminal (UE1) MAC address.

The WiFi AP concentrator notifies the other WiFi AP (WiFi AP2) as an ACK message that the message has been well received, and the WiFi AP concentrator registers the user terminal (UE1) MAC address in Port2. Also notify.

The other WiFi AP (WiFi AP2) confirms that the registration of the new user terminal is completed, and whether the service is started to the newly registered terminal with an ACK message to the WiFi AP concentrator, and the MAC address without IP exchange through this process It is possible to ensure high-speed mobility between small cells in a dense structure only by port movement.

5 is a diagram illustrating a service cell determination method based on a hysteresis curve in a WiFi cell overlap period according to the present invention.

In the following, a method of determining a service cell using a hysteresis curve in a redundant section of two cells will be described.

The WiFi cell overlapping section includes an overlapping section cell determining step of determining a service cell of the user terminal through a change in the hysteresis curve with respect to the direction in which the user terminal moves in the cell and the electric field strength of the user terminal received by the WiFi AP. .

Considering that it is difficult to predict which direction the user terminal will move in the overlapping cell with which reception strength value, and thus it is difficult to determine the existing field strength only, most of the movement in the overlapping cell determination step is performed. Since it moves with periodicity in a direction and moves with a certain range, it is possible to set the change of the electric field strength according to the moving direction and the overlapping area so as to follow the variation of the hysteresis curve as shown in FIG. To determine the serving cell.

In particular, in the overlapping cell determination step, the area of the cell overlapping section is based on the area of the hysteresis curve based on the x-axis (movement direction between cells) and the y-axis (field strength of the user terminal received by the WiFi AP). To determine the service cell, the field strength tracking value and the field strength change amount are set.

An operation method for determining a serving cell from the hysteresis curve shown in FIG. 5 is as follows.

1) The area of the cell overlap section is the area of the hysteresis curve.

 The area of ①, ②, ③, ④ is the area where two cells overlap when the user terminal moves from Cell # 1 to Cell # 2 or Cell # 2 to Cell # 1, and the horizontal axis is the direction in which the terminal moves in the cell. Is the strength of the electric field of the user terminal received by the WiFi AP and is expressed as an absolute value.

2) If five values (α, ε, μ, ω, β) are set during system operation, the service cell in the overlap region is determined by the programmed hysteresis curve.

3) Field strength tracking value and field strength change for overlapping service cell

| Δε | is the amount of change in the received electric field strength increase when the UE moves in Cell # 1, where the tracking start value is μ and the end value is ε.

| Δβ | is the amount of change in the reduction of the received electric field strength when the terminal moves in Cell # 1, and the tracking start value is β and the end value is μ.

| Δω | is the amount of change in the received electric field strength increase when the terminal moves in Cell # 2, and the tracking start value is μ and the end value is ω.

| Δα | is the amount of change in the reduction of the received electric field strength when the UE moves in Cell # 2, where the tracking start value is α and the end value is μ.

4) The change or | length of | Δθ | and | Δρ | is the value for determining the final serving cell in the overlapping cell, and these elements are the cell movement time of the UE in the cell overlapping area or the time changed to the serving cell.

The smaller | Δθ | and | Δρ |, the faster the service cell in the overlap region is determined (real time service).

The larger | Δθ and | Δρ |, the slower the serving cell in the overlap region is determined (non real-time service).

6 is a diagram illustrating a handoff procedure after cell priority determination in an overlapping section according to the present invention.

Next, the MAC registration and release procedure after priority cell determination at cell boundaries and overlapping regions will be described.

Priority cell determination step of determining a priority cell for serving the user terminal when the user terminal moves from the WiFi AP (WiFi AP1) to another WiFi AP (WiFi AP2) in the WiFi cell boundary and overlapping intervals; After this determination, a MAC address processing step of performing MAC address registration and release according to handoff progress is included.

In the priority cell determination step, the tracking change interval and the service cell determination are performed according to a predefined hysteresis curve in response to a preset level in order to track the received electric field strength of the user terminal.

In particular, the determining of the priority cell may reduce a service start (ADD) / stop (DROP) level and tracking change set in advance by the WiFi AP (WiFi AP1) in the overlapping interval of the WiFi AP (WiFi AP1) and another WiFi AP (WiFi AP2). If the electric field strength of the location where the section crosses (③ point) is detected as the same as the electric field strength of the user terminal, the user terminal periodically tracks the electric field strength received from the WiFi AP (WiFi AP1), and the electric field strength decreases through the tracking. After a certain time, if the electric field strength decreases until the overlapping section electric field strength and tracking change decreases to the intersection point (④ point), the WiFi AP (WiFi AP1) stops the user terminal service (DROP) and releases the MAC address of the user terminal. The service interruption step of requesting the WiFi AP concentrator and the electric field strength and the user at the point where the other WiFi AP (WiFi AP2) intersects the overlapping section electric field strength and the increase in the tracking change interval (point ①) When the electric field strength of the horse is detected to be the same, the user terminal periodically tracks the electric field strength received from another WiFi AP (WiFi AP2), and checks whether the electric field strength is increased through the tracking to start a preset service after a predetermined time (ADD). If the field strength increases to the point where the DROP level and the tracking change increase interval cross (point ②), another WiFi AP (WiFi AP2) starts the user terminal service (ADD) and registers the MAC address of the user terminal. A service registration step of requesting the AP concentrator will be included.

A process of determining the priority cell at the cell boundary shown in FIG. 6 is as follows.

When the UE1 moves slowly in the WiFi cell overlap region, the level for tracking the received electric field strength of the UE1 is set in advance, and the tracking variation interval and the service decision are preprogrammed hysteresis curves. Follow.

If the UE1 is moving slowly in an overlapping region of two cells while moving from a WiFi AP1 to another WiFi AP2, it is necessary to determine the priority of which cell is provided in the overlapping region. If the electric field strength of the UE1 is detected by the WiFi AP in the same manner as the electric field strength at the point ③, the power of the UE1 is fixed to the electric field strength received by the WiFi AP. Start tracking at the time interval, and check if the electric field strength detected by tracking decreases. After a certain time, if the electric field strength is reduced to the same value as ④ at the point location, the WiFi AP (WiFi AP1) is serviced to the user terminal (UE1). DROP and request the MAC address release of the UE1 to the WiFi AP concentrator.

At the same time, if the electric field strength of the user terminal UE1 is detected to be equal to the electric field strength at the ① location, the other WiFi AP (WiFi AP2) receives an electric field received by the other WiFi AP (WiFi AP2). Start tracking the intensity at regular time intervals. At this time, check if the detected electric field strength is increased, and after a certain time, if it increases to the same value as the electric field strength at the point ②, the WiFi AP (WiFi AP2) is the user terminal (UE1). (ADD) and request the MAC address registration of the UE1 to the WiFi AP concentrator.

In addition, the MAC address processing step is a tracking level that the WiFi AP (WiFi AP1) and other WiFi AP (WiFi AP2) request the WiFi AP concentrator in advance to set the field strength tracking level for tracking the field strength of the cell overlap region of the user terminal The setting request step, the WiFi AP concentrator notifies the WiFi AP (WiFi AP1) of the tracking start level setting value of the ③ point and the tracking end level setting value of the point ④, ① the tracking start level setting value of the point ② The tracking level setting step of notifying the tracking end level setting value to another WiFi AP (WiFi AP2), the service stopping step described previously, and the MAC address of the user terminal registered in the WiFi AP concentrator have been released. Wi-Fi AP1) is notified and confirms whether the MAC address release of the user terminal, the service termination step of finally terminating the user terminal service, the previously described service registration step, WiFi AP Another WiFi AP (WiFi AP2) is notified that the MAC address of the user terminal is newly registered in the ship equipment, and the WiFi AP (WiFi AP2) confirms whether or not the MAC address of the user terminal is registered, and then starts the service of the user terminal service. Steps.

Here, in the tracking level setting request step, the WiFi AP concentrator transmits an ACK message for receiving the field strength tracking level setting request to each of the WiFi AP (WiFi AP1) and the other WiFi AP (WiFi AP2). The WiFi AP (WiFi AP1) and other WiFi APs (WiFi AP2) set their own level settings and then send an ACK message to the WiFi AP concentrator, and in the service stop phase, the WiFi AP concentrator is the MAC address of the user terminal. Send an ACK message for the release request to the WiFi AP (WiFi AP1), in the service termination step, the WiFi AP (WiFi AP1) transmits an ACK message for the MAC address release to the WiFi AP concentrator, and in the service registration step The concentrator sends an ACK message for the MAC address registration request of the user terminal to another WiFi AP (WiFi AP2), and in the service initiation phase, the other WiFi AP (WiFi AP2) sends the MAC address to the WiFi AP concentrator. And it transmits an ACK message for the lock.

Looking at the MAC registration and release procedure at the cell boundary shown in Figure 6 as follows.

If the user terminal UE1 is moving slowly in an overlapping region of two cells while moving from a WiFi AP1 to another WiFi AP2, the WiFi AP1 and the other WiFi AP2 are connected to the user. The UE AP requests the WiFi AP concentrator to set the field strength tracking level for the field strength tracking in the cell overlap region of the UE UE1, and sends an ACK message to each WiFi AP for receiving the request.

The WiFi AP concentrator notifies the WiFi AP (WiFi AP1) of the setting value of the tracking start level at the point ③ and the setting value of the tracking end level at the point ④, and at the ② point and The tracking end level setting value of the notification to other WiFi AP (WiFi AP2), each WiFi AP sets the reported value to the device and sends an ACK message to the WiFi AP concentrator.

Since the UE1 moves slowly from the overlapping area of the two cells while moving from the WiFi AP1 to another WiFi AP2, the electric field strength of the UE1 from the WiFi AP1 is changed. ③ If the same as the electric field strength at the point location is detected, the power of the user terminal UE1 starts tracking the electric field strength received by the WiFi AP (WiFi AP1) at regular time intervals. ④ After a certain period of time, if it decreases to the same value as the electric field strength at point ④, the WiFi AP (WiFi AP1) stops the service to the user terminal UE1 (DROP) and releases the MAC address of the user terminal UE1. Request to WiFi AP concentrator.

The WiFi AP concentrator notifies the WiFi AP (WiFI AP1) as an ACK message that it has received the requested message, releases the MAC address of the user terminal (UE1) registered in Port1 from the WiFi AP concentrator, and then sends it to the WiFi AP (WiFi AP1). Notify and the WiFi AP (WiFi AP1) sends a ACK message to the WiFi AP concentrator after confirming again whether the user terminal (UE1) MAC release, and then service of the user terminal (UE1) in the WiFi AP (WiFi AP1) Finally terminates.

At the same time, if the electric field strength of the user terminal UE1 is detected to be equal to the electric field strength at the ① location, the other WiFi AP (WiFi AP2) receives an electric field received by the other WiFi AP (WiFi AP2). If you start tracking the intensity at regular time intervals and check if the detected field strength increases, if the field strength increases to the same value as the field strength at the point ②, then another WiFi AP (WiFi AP2) will track the field strength. To exit.

In addition, the other WiFi AP (WiFi AP2) requests the registration of the MAC address of the user terminal (UE1) to the WiFi AP concentrator, and the WiFi AP concentrator notifies the other WiFi AP (WiFI AP2) as an ACK message that the requested message has been received. While the WiFi AP concentrator newly registers the MAC address of the UE1 in Port2, it notifies the other WiFi AP (WiFi AP2) and the other WiFi AP (WiFi AP2) determines whether to register the MAC address of the UE1. After confirming again, an ACK message is sent to the WiFi AP concentrator, and then the user terminal UE1 service at another WiFi AP (WiFi AP2) is finally started.

In the above description with reference to the accompanying drawings, the present invention has been described with reference to specific shapes and directions, but the present invention may be variously modified and changed by those skilled in the art, and such modifications and changes are included in the scope of the present invention. Should be interpreted as

Claims (11)

delete delete A WiFi access point (AP) having only two layers of a physical layer and a data link layer in an OSI 7 layer; A WiFi AP concentrator having three or more layers of a physical layer, a data link layer, and a network layer and connected to at least one or more of the WiFi APs in a second layer; An IP data concentrator that manages the WiFi AP and the WiFi AP concentrator and allocates an IP (Internet Protocol) and is connected to an external network to deliver IP data to the WiFi AP via the WiFi concentrator;
The WiFi AP in the data service to the user terminal through the connected external network requests the WiFi AP concentrator to release the MAC (Media Access Control) address of the moving user terminal, and the new WiFi AP connected to the user terminal is the WiFi AP concentrator. In the fast handoff method using a system that registers only the MAC address of the user terminal in the device so that the handoff is performed without IP exchange when moving between cells of the user terminal,
A MAC release requesting step of requesting a release of a user terminal MAC address from the WiFi AP concentrator to the WiFi AP concentrator if the received electric field strength of the user terminal is not detected by the WiFi AP (WiFi AP1); A MAC release step of the WiFi AP concentrator releasing a self-registered user terminal MAC address in response to a user terminal MAC address release request; A new MAC registration request step of requesting the WiFi AP concentrator to register a new MAC address of the user terminal when the WiFi AP concentrator scans and receives the received electric field strength of the user terminal from another WiFi AP (WiFi AP2); Registering a new MAC address by the WiFi AP concentrator to register a new MAC address of a user terminal; In the overlapping section of the WiFi cell, including the overlapping section cell determining step of determining the service cell of the user terminal through the amount of change in the hysteresis curve with respect to the direction in which the user terminal moves in the cell and the field strength of the user terminal received by the WiFi AP. A fast handoff method for guaranteeing mobility of a dense WiFi small cell network.
The method according to claim 3,
In the MAC release request step, the WiFi AP concentrator sends an ACK (Acknowledge) message for receiving the MAC address release request to the WiFi AP (WiFi AP1),
In the MAC release step, the WiFi AP concentrator transmits a MAC address release completion ACK message to the WiFi AP (WiFi AP1), and the WiFi AP (WiFi AP1) sends a final release ACK message to the WiFi AP concentrator after reconfirming the user terminal. Send,
In the new MAC registration request step, the WiFi AP concentrator transmits an ACK message for receiving a new MAC address registration request to another WiFi AP (WiFi AP2).
In the new MAC registration step, the WiFi AP concentrator transmits an ACK message for completing the registration of a new MAC address to another WiFi AP (WiFi AP2), and another WiFi AP (WiFi AP2) for the service start of a newly registered user terminal. A fast handoff method for guaranteeing mobility of a dense WiFi small cell network, characterized by transmitting an ACK message to a WiFi AP concentrator.
delete The method according to claim 3,
In the overlapping cell determination step, the area of the cell overlapping section is based on the area of the hysteresis curve based on the x-axis (movement direction between cells) and the y-axis (field strength strength of the user terminal received by the WiFi AP). A fast handoff method for guaranteeing mobility of a dense WiFi small cell network, characterized by setting a field strength tracking value and a field intensity change amount to determine a cell.
The method according to claim 6,
In WiFi cell boundaries and overlapping intervals,
A priority cell determining step of determining a priority cell for serving the user terminal when the user terminal moves from the WiFi AP (WiFi AP1) to another WiFi AP (WiFi AP2);
And a MAC address processing step of performing MAC address registration and release according to handoff progress after the priority cell is determined. 2. The fast handoff method for guaranteeing mobility of a dense WiFi small cell network.
The method according to claim 7,
The priority cell determination step includes a tracking change interval and a service cell determination according to a predefined hysteresis curve in response to a predetermined level to track the received electric field strength of the user terminal. Fast handoff method to ensure mobility.
The method according to claim 8,
The priority cell determination step,
In the overlapping section of the WiFi AP (WiFi AP1) and the other WiFi AP (WiFi AP2), the position where the service start (ADD) / stop (DROP) level and the tracking change reduction section intersect in advance (the point ③) If the electric field strength of the user terminal is detected to be the same as the electric field strength of the user terminal, the user terminal periodically tracks the electric field strength received from the WiFi AP (WiFi AP1), and checks whether the electric field strength is reduced through tracking and overlaps the interval after a certain time. Reduced field strength and tracking variation If the field strength decreases to the intersection position (④ point), the WiFi AP (WiFi AP1) stops the user terminal service (DROP) and requests the WiFi AP concentrator to release the MAC address of the user terminal. Stopping step;
If the other WiFi AP (WiFi AP2) detects that the electric field strength of the position where the overlapping section electric field strength and the tracking change increase section intersect (① point) and the electric field strength of the user terminal are the same, the user terminal is connected to another WiFi AP (WiFi AP2) Track the received electric field strength periodically and check if the electric field strength is increased through tracking to the point where the preset service start (ADD) / stop (DROP) level and the tracking change increase interval intersect after a certain time (point ②). When the electric field strength increases, another WiFi AP (WiFi AP2) starts a user terminal service (ADD) and a service registration step of requesting the MAC address registration of the user terminal to the WiFi AP concentrator; dense WiFi small, characterized in that it comprises a; Fast handoff method to guarantee mobility of cell network.
The method according to claim 9,
The MAC address processing step,
A tracking level setting request step of requesting, by the WiFi AP (WiFi AP1) and another WiFi AP (WiFi AP2), a field strength tracking level setting for field strength tracking of a cell overlap region of a user terminal in advance to the WiFi AP concentrator;
The WiFi AP concentrator notifies the WiFi AP (WiFi AP1) of the tracking start level setting value of the point ③ and the tracking end level setting value of the point ④, and sets the tracking starting level setting value of the point and the tracking end level setting of the point ②. A tracking level setting step of notifying another WiFi AP (WiFi AP2) of the value;
Stopping the service;
A service termination step of confirming whether the MAC address of the user terminal is released after the WiFi AP (WiFi AP1) is notified that the MAC address of the user terminal registered in the WiFi AP concentrator is released;
Registering the service;
Another WiFi AP (WiFi AP2) is notified that the MAC address of the user terminal is newly registered in the WiFi AP concentrator, and the WiFi AP (WiFi AP2) confirms whether or not the MAC address of the user terminal is registered and finally starts the user terminal service. A service initiation step; comprising: a fast handoff method for guaranteeing mobility of a dense WiFi small cell network.
The method according to claim 10,
In the tracking level setting request step, the WiFi AP concentrator transmits an ACK message for receiving a field strength tracking level setting request to each of the WiFi AP (WiFi AP1) and the other WiFi AP (WiFi AP2),
In the tracking level setting step, the WiFi AP (WiFi AP1) and other WiFi APs (WiFi AP2) set the level setting value notified by themselves, and then send an ACK message to the WiFi AP concentrator.
In the service stopping step, the WiFi AP concentrator transmits an ACK message for the MAC address release request of the user terminal to the WiFi AP (WiFi AP1),
In the service termination step, the WiFi AP (WiFi AP1) transmits an ACK message for the release of the MAC address to the WiFi AP concentrator,
In the service registration step, the WiFi AP concentrator transmits an ACK message for the MAC address registration request of the user terminal to another WiFi AP (WiFi AP2),
In the service initiation step, another WiFi AP (WiFi AP2) is a fast handoff method for guaranteeing the mobility of the dense WiFi small cell network, characterized in that for transmitting the ACK message for the MAC address registration to the WiFi AP concentrator.

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