KR20160011130A - Macrocell device and method for mitigating uplink signal interference result from macrocell device - Google Patents

Abstract

According to an embodiment of the present invention, a method for mitigating uplink signal interference of a macro cell terminal comprises the following steps of: obtaining information of at least one small cell, which exists in surroundings of the macro cell terminal, through a cellular link of the small cell; transmitting the information of at least one small cell to a macro cell; receiving the information of the small cell, which receives interference of an uplink signal from the macro cell; setting a wireless LAN link with the small cell, which receives the interference of the uplink signal; obtaining an access permit to the cellular link of the small cell through the set wireless LAN link; and performing hand-over from the macro cell to the small cell of which an access mode is converted from a closed access mode to a hybrid access mode.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for mitigating uplink signal interference generated from a macro cell terminal and a macro cell terminal,

The present invention relates to a method for mitigating uplink signal interference generated from a macro cell terminal and a macro cell terminal.

Recently, in 3GPP (3rd generation partnership project) LTE-A Release 12 or later communication standard, a cellular-WLAN interworking, a small cell, There are discussions on the performance enhancement technology of the receiver and dual connectivity technology. In addition, technology discussions are ongoing on a new topic called LTE-WLAN Radio Level Integration that evolves from interworking to traffic-steering between cellular and wireless LANs and extends carrier aggregation to wireless LAN frequencies. , And the utilization of the wireless LAN and the standardization of 3GPP are being promoted.

On the other hand, in a cellular-wireless LAN interworking or a small cell receiver connection, in a system where heterogeneous cells are mixed, such as a small cell environment in which a femtocell and a macrocell coexist, the mutual interference is effectively controlled, Or controlling the access permission of the terminal is one of the essential technical elements for effectively using the cellular-wireless LAN resources.

In this process, if inter-cell interference in the same frequency resource is very large, it is difficult for the UE to communicate with a specific eNode B (eNode B), and thus, coverage loss or deadzone occurs, ) May be difficult to maintain. In order to overcome this, the cellular-wireless LAN interworking technology is considered to be a very important technology after 3GPP LTE-A Rel.13, and it is expected that LTE-Unlicensed (LTE-U) such as licensed assisted access (LAA) ), IEEE 802.11, and so on, and is expected to be utilized as a variety of application products and standardization technologies utilizing a license-exempt band in Wi-Fi wireless LAN communication.

On the other hand, the cellular network base station can transmit / receive data to / from terminals included in a wide service area, i.e., coverage. However, the cellular network base station has a problem that the data transmission rate in the boundary area of the cell is relatively lower than that of the central area, instead of the coverage area being wide. In order to solve this problem, when the coverage of the cell is designed to be small, interference occurs when the same frequency is used between cells. This type of interference will be described with reference to Figs. 1A and 1B.

1A and 1B are views for explaining types of interference in a multi-layer network structure.

1A, the small cell 20a, 20b, 20c differs from the macro cell 10 in the arrival distance of the radio wave because the radio transmission power is different from the macro cell 10 in the case of the small cells 20a, 20b and 20c. As a result, it is difficult for the terminals 100, 21a, 21b, 21c, and 21d connected to the macro cell 10 or the small cells 20a, 20b, and 20c to maintain the connection due to interference from other cells . At this time, the type of interference can be largely classified into a cross-tier interference and a co-tier interference.

Heterogeneous layer interference is a type of interference occurring between different network elements, which corresponds to the interference types corresponding to (1), (2), (3) and (4) in FIG. In this case, the situation where the uplink signal interference is caused may be a case where the macro cell terminal 100 causes the uplink signal interference to the femtocell 20a as in (1) and the case where the small cell terminal 21b is in the macro cell The mobile station 10 may cause uplink signal interference. Unlike the case where the downlink signal interference occurs, the case where the macrocell 10 causes the downlink signal interference to the small cell terminal 21a and the case where the small cell 20b is the macrocell There is a case where downlink signal interference is caused to the terminal 100 in some cases.

Homogeneous layer interference is a type of interference occurring between network elements of the same layer, which is the interference corresponding to ⑤ and ⑥ in FIG. 1B. At this time, when the small cell terminal 21c causes the uplink signal interference to the small cell 20b in the situation where the uplink signal interference is occurring in the case of (5), downlink signal interference occurs in the case of (6) There is a case where the small cell 20c causes the downlink signal interference to the small cell terminal 21d.

On the other hand, in the case of heterogeneous layer interference, the operations of the terminal and the base station can be set differently according to the terminal access permission scheme of the small cell. In this case, the small cell's terminal access permission mode is a mode in which all terminals can be connected, an open connection mode in which all terminals can be connected, a closed connection mode in which only the terminal having membership is available, and a state In hybrid connection mode.

In the case of the closed connection mode of the connection method of the small cell, if a terminal, which is not allowed to connect to the periphery, transmits a strong signal in the uplink, the small cell in the periphery may receive coverage of the small cell due to strong interference, It is impossible to provide a communication service to be supported by the mobile terminal. Therefore, in consideration of interference between different types of cells, a wireless communication system needs a technique capable of maintaining the connection even when strong interference with a level that is difficult to maintain connection is generated. In particular, And to support maintenance and change.

In this regard, Korean Patent Laid-Open Publication No. 10-2014-0073164 entitled " Service mode of femto base station and method of managing access permission to terminals ") discloses a method of controlling access using a femto base station Thereby changing the service mode of the femto base station. However, in addition to the above prior art, there is a problem that the prior art can not solve strong interference caused from the macro cell terminal.

Some embodiments of the present invention are directed to a method and apparatus for controlling uplink signal interference between a macro cell and a small cell base station that can overcome uplink signal interference caused by a macro cell terminal in a multi- Provide a mitigation method.

It should be understood, however, that the technical scope of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

According to a first aspect of the present invention, there is provided a method for mitigating uplink signal interference in a macro cell terminal, the method comprising the steps of: receiving, via a cellular link of a small cell, Obtaining information of the small cell; Transmitting information of the at least one small cell to the macro cell; Receiving information on a small cell that is interfered with by the uplink signal from the macro cell; Setting a wireless LAN link with a small cell that is interfered with by the uplink signal; Acquiring access permission to the cellular link of the small cell via the set wireless LAN link and handing over from the macro cell to the small cell in which the access mode is changed from the closed connection mode to the hybrid access mode.

The macro cell terminal according to the second aspect of the present invention includes a cellular communication module; Wireless LAN communication module; A memory for storing a program for transmitting and receiving a macro cell and a small cell, and a processor for executing the program, wherein the processor executes, by executing the program, from the cellular link of the small cell through the cellular communication module, Information of at least one small cell existing in the periphery of the cell terminal and transmits the information of the at least one small cell to the macro cell through the cellular link of the macro cell and receives the interference of the uplink signal from the macro cell Wherein the mobile station receives information on a small cell and establishes a wireless LAN link with a small cell interfering with the uplink signal through the wireless LAN communication module, . At this time, handover is performed from the macro cell to the small cell in which the access mode is changed from the closed connection mode to the hybrid mode.

According to any one of the above-mentioned means for solving the problems, when the macrocell terminal causes strong interference to the neighboring small cell due to the uplink signal transmission, the small cell search for controlling the interference to the small cell is performed, Handover can overcome the interference of the strong uplink signal caused by the small cell.

Further, in the handover to the small cell, access permission is acquired through the cellular link of the small cell through the wireless LAN link with the small cell, so communication can be performed without releasing the cellular link connection with the macro cell, It is possible to solve the traffic load problem of the small cell due to obtaining the access permission through the link.

1A and 1B are views for explaining types of interference in a multi-layer network structure.
2 is a conceptual diagram illustrating an environment of a wireless communication system in which a macro cell terminal according to the present invention operates.
3 is a diagram illustrating an example of uplink signal interference occurring in a multi-layer cell environment.
4 is a diagram schematically illustrating a method of mitigating uplink signal interference generated from a macro cell terminal according to an embodiment of the present invention.
5 is a flowchart illustrating a method of mitigating uplink signal interference generated from a macro cell terminal according to an embodiment of the present invention.
6 is a block diagram of a macrocell terminal according to an exemplary embodiment of the present invention.

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

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when a part is referred to as "including " an element, it does not exclude other elements unless specifically stated otherwise.

2 is a conceptual diagram illustrating an environment of a wireless communication system in which a macro cell terminal according to the present invention operates.

The macro cell 10 generally provides a wide service area and the small cell 20 provides a relatively narrow service area than the macro cell 10. [ One or more of such small cells 20 are installed in the service area of the macro cell 10 in a superimposed manner. At this time, the macro cell 10 and the small cell 20 have different carrier frequencies and may use the same carrier frequency. The macro cell 10 and the small cell 20 are connected to each other through a backhaul. At this time, the backhaul can be variously implemented as a power line communication device, a telephone line communication device, a cable home (MoCA), an Ethernet, an IEEE1294, an integrated wired home network, and an RS-485 control device.

Meanwhile, the macro cell terminal 100 can connect to the macro cell 10 or the small cell 20 to transmit and receive data. The macro cell terminal 100 may include a mobile station MS, a user equipment (UE), a user terminal (UT), a wireless terminal, an access terminal (AT), a terminal, a subscriber unit, A subscriber station (SS), a wireless device, a wireless communication device, a wireless transmit / receive unit (WTRU), a mobile node, a mobile, or other terminology. Various embodiments of the terminal may be implemented in a wireless communication device that is guaranteed to be portable and mobility, such as a Personal Communication System (PCS), a Global System for Mobile communications (GSM), a Personal Digital Cellular (PDC), a Personal Handyphone System (PHS) Digital Assistants), IMT (International Mobile Telecommunication) -2000, Code Division Multiple Access (CDMA) -2000, W-Code Division Multiple Access (W-CDMA), Wibro (Wireless Broadband Internet) Handheld based wireless communication devices, but is not limited thereto.

A base station such as the macro cell 10 and the small cell 20 in the present invention generally refers to a fixed or mobile point in communication with a terminal and includes a base station, a Node- , an eNode-B, a base transceiver system (BTS), an access point, a relay, and a femto-cell.

3 is a diagram illustrating an example of uplink signal interference occurring in a multi-layer cell environment.

In the case of the small cells 20a and 20b such as the femtocell operating in the closed connection mode, only the specific terminals 21a and 21b can be set to be connectable. That is, the small cells 20a and 20b allow only the registered users 21a and 21b to connect. At this time, when the macrocell terminal 100 exists in the vicinity of the small cells 20a and 20b, as shown in FIG. 3, serious interference occurs in the uplink, and a dead zone where communication is impossible occurs.

3, when the macrocell terminal 100 connected to the macrocell 10 transmits an uplink signal to the macrocell 10, the uplink interference in the multi-layered cell environment is a closed- The small cell 20a in the vicinity of the macrocell terminal 100 is interfered with due to the strong uplink signal transmitted from the macrocell terminal 100. [ In this case, the small cell 20a can not receive the signal transmitted to the small cell 20a by the small cell terminal 21a in the uplink, and communication of the entire small cell 20a may become impossible. That is, due to the uplink signal interference caused by the macro cell terminal 100, the small cell 20a and the small cell terminal 21a fall into the dead zone area excluded from the communication coverage. In order to solve such a problem, the uplink signal interference mitigation method according to the present invention generates uplink interference by recognizing the interference by the small cells 20a and 20b and requesting the macrocell 10 to perform interference management It is possible to solve the interference problem by handing over the macro cell terminal 100 to the small cell terminal 20a.

Meanwhile, in the present invention, an uplink (UL, or uplink) means a method of transmitting / receiving data to / from a base station by a terminal, and a downlink (DL or downlink) It means the method of sending and receiving.

Hereinafter, the uplink signal interference mitigation method will be described in detail with reference to FIGS. 4 to 5. FIG.

FIG. 4 is a diagram schematically illustrating a method of mitigating uplink signal interference generated from a macrocell terminal 100 according to an embodiment of the present invention. Referring to FIG.

4, when the macro cell terminal 100 connected to the macro cell 10 transmits a strong uplink signal around the macro cell 10, the small cell located near the macro cell terminal 100 20 to receive the uplink signal from the small cell terminal, the small cell 20 can not receive the uplink signal of the small cell terminal due to the strong uplink signal interference of the macro cell terminal 100. In this case, the macro cell terminal 100 having no membership of the small cell 20 can not perform the handover to the small cell 20 even though the small cell 20 exists in the periphery, Thereby causing uplink signal interference.

If there is such an uplink signal interference, the small cell 20 detects this interference (S410), and transmits the MAC address of the macro cell through a communication channel formed through a backhaul (for example, an Ethernet network The macro cell 10 having received the interference management request requests interference management (IM) to the cell 10. Upon receiving the interference management request, the macro cell 10 transmits the interference management request to one or more terminals connected in the macro cell 10, The one or more macro cell terminals 100 connected to the macro cell 10 are searched for one or more small cells 20 located in the vicinity thereof, The macro cell terminal 100 acquires the information of the cell 20 through the cellular link of the small cell 20 via the cellular link of the small cell 20 Information of the small cell 20 to be transmitted periodically or at a specific time point is received The information of the small cell 20 may be information on the ID of the small cell 20 and information on the current service mode and may be information on the small cell 20 existing in the vicinity of the small cell 20 based on the ID information, The information of the small cell 20 can be transmitted to the small cell 20 such as the PIC (Physical Cell ID) and the RSSI (Received Signal Strength Indication) of the small cell 20 in the 3GPP, for example. As shown in Fig.

On the other hand, the macro cell terminal 100 can receive the information of the small cell as described above through the cellular link of the small cell 20 operating in the closed connection mode, and the cellular phone of the small cell 20 Data can be exchanged through the cellular link of the small cell 20 when the access is granted through the link and then handed over.

The macro cell terminal 100 may acquire the information of the small cell 20 through the cellular link of the macro cell 10. In this case, And information on the small cell 20 to be managed. Accordingly, the macro cell terminal 100 can scan only the small cell 20 managed by the macro cell 10, rather than scanning all the small cells 20 existing in the vicinity thereof.

The macro cell terminal 100 transmits the acquired at least one small cell 20 information to the macro cell 10 at step S430 and the macro cell 10 transmits the acquired small cell 20 information to the small cell 20 through the backhaul 20, Information of one or more candidate macrocell terminals 100 suspected of causing strong interference with neighboring terminal information is transmitted (S435). The macro cell 10 transmits information of the at least one small cell 20 that is interfered with the uplink signal caused by the macro cell terminal 100 to the macro cell terminal 100 at step S440. Since the small cell 20 includes the wireless LAN 30 as a base station that supports communication in the indoor or hot spot as well as the short coverage like the wireless LAN 30, The information of the wireless LAN 30 can be transmitted together with the information of the small cell 20.

Next, the macro cell terminal 100 activates the wireless LAN (S445). When the wireless LAN 30 of the small cell 20 is activated, the macro cell terminal 100 connects to the wireless LAN 30 of the small cell 20, If it is not activated, the wireless LAN 30 is activated by requesting activation of the wireless LAN 30 of the small cell 20 (S450). The mobile station 20 performs active scanning or passive scanning using the information of the small cell 20 and the information of the wireless LAN 30 so that the radio waves of the small cell 20, And connects to the LAN link (S455). Here, passive scanning is a method of checking whether a corresponding wireless LAN link exists by listening to a specific channel for a predetermined time and searching the macrocell terminal 100, and active scanning is performed when the macrocell terminal 100 is defined in the wireless LAN A probe request and a probe response are exchanged with a wireless LAN existing on a corresponding channel through a specific channel to search for a neighboring wireless LAN.

After establishing the wireless LAN link with the small cell 20 which is interfered with the uplink signal as described above, the small cell 20 obtains the access permission through the cellular link of the small cell 20 through the wireless LAN link of the set small cell 20 (S460). After the macro cell terminal 100 acquires the access permission to the cellular link of the small cell 20, the small cell 20 changes the access mode from the closed connection mode to the hybrid connection mode (S465) The terminal 100 receives a handover command from the macrocell 10 and is handed over from the macrocell 10 to the small cell 20 (S470).

On the other hand, the small cell 20 may allow access to any terminal that does not have membership, by changing the access mode from the closed connection mode in which only the specific terminal is allowed to access to the hybrid connection mode. Accordingly, the small cell 20 can notify the specific terminal, if necessary, that its access mode has been changed to the hybrid access mode.

Alternatively, in changing the access mode to the hybrid access mode, the small cell 20 may allow access only to the macro cell terminal 100 that has acquired the access permission via the wireless LAN link. In this case, the small cell 20 may not notify the specific terminal that its access mode is changed to the hybrid access mode, as described above.

Meanwhile, the macro cell terminal 100 can communicate with the macro cell 10 through the cellular link of the macro cell 10 while communicating with the small cell 20 via the wireless LAN link (S400). As described above, according to the present invention, data can be transmitted / received by using two communication modules independently, and it is possible to support interworking between WLAN and LTE without releasing a cellular link connection, It can have an effect of being able to process it.

Hereinafter, an uplink signal interference mitigation method generated from the macrocell terminal 100 according to the present invention will be described in more detail with reference to FIG.

5 is a flowchart of a method of mitigating uplink signal interference generated from a macrocell terminal 100 according to an embodiment of the present invention.

The uplink signal interference mitigation method generated from the macro cell terminal 100 according to an embodiment of the present invention firstly transmits the uplink signal interference to the macro cell terminal 100 via the cellular link of the small cell 20, Information of the small cell 20 is acquired (S510), and information of the at least one small cell 20 is transmitted to the macro cell 10 (S520).

At this time, the small cell 20 receives interference due to the uplink signal generated from the macro cell terminal 100, and requests the macrocell 10 to perform interference management for the uplink signal in order to mitigate such interference . The macro cell 10 can request information of one or more small cells 20 existing around the macro cell terminal 100 in response to the interference management request. Accordingly, the macro cell terminal 100 acquires the information of at least one small cell 20 existing around the small cell 20 via the cellular link, and transmits the information to the macro cell 10. The macro cell 10 compares the information of the at least one macro cell terminal 100 connected to the macro cell 10 with the information of at least one small cell 20 transmitted by the macro cell terminals 100, It is possible to extract one or more candidate macro cell terminals 100 causing uplink interference with the small cell 20 and to transmit the information of the candidate macro cell terminal 100 to the small cell 20 through a backhaul. The macro cell terminal 100 can acquire the information of the small cell 20 through the cellular link of the macro cell 10. In this case, the received information of the small cell 20 is transmitted to the macro cell 10 And information on the small cell 20 to be managed. Accordingly, the macrocell terminal 100 can scan only the small cell 20 managed by the macrocell 10, rather than scanning all the small cells 20 existing in the vicinity of the macrocell terminal 100.

Next, the macro cell terminal 100 receives the information of the small cell 20 which is interfered with the uplink signal from the macro cell 10 through the cellular link of the macro cell 10 (S530). That is, the macro cell 10 can transmit the information of the small cell 20 that is interfered with the uplink signal to one or more macro cell terminals 100 connected to the macro cell 10. At this time, the information of the small cell 20 may include information on the current service mode of the small cell 20. That is, the macro cell terminal 100 can acquire information on whether the small cell 20 is operating in the open connection mode, the closed connection mode, or the hybrid mode.

The information of the small cell 20 may include information of the wireless LAN 30 of the small cell 20. The wireless LAN 30 information may include at least one of an SSID and a MAC address of the wireless LAN 30. However, the information of the wireless LAN 30 is not limited thereto and may include various information as needed.

Next, the macro cell terminal 100 activates the wireless LAN (S540). At this time, if the wireless LAN of the macro cell terminal 100 is already in use, the wireless LAN in use can be used without being separately activated. In this manner, in a state where the wireless LAN of the macro cell terminal 100 is activated, the macro cell terminal 100 establishes a wireless LAN link with the small cell 20 that is interfered with the uplink signal (S550). In general, the terminal and the small cell 20 include a wireless LAN 30. [ Therefore, when the small cell 20 is operating through the wireless LAN 30, the macro cell terminal 100 can establish a wireless LAN link with the small cell 20, ) Is not activated, it may request to activate the wireless LAN 30 of the small cell 20 through the uplink. That is, the macro cell terminal 100 can activate the function of the wireless LAN 25 of the small cell 20 by directly transmitting the uplink signal that the small cell 20 can recognize. In this case, the macrocell terminal 100 can transmit the preset uplink signal to the small cell 20 via the cellular link of the small cell 20 to activate the function of the wireless LAN 25 of the small cell 20 have. For example, a specific random access sequence may be predefined and transmitted as an uplink signal for activating the WLAN 25 through the RACH. At this time, the system information of the small cell 20 can be obtained by the macro cell terminal 100 through the downlink control signal of the small cell 20 or by receiving the information from the macro cell 10.

In addition, the macrocell terminal 100 may request to activate the function of the wireless LAN 25 of the corresponding small cell 20 through the uplink to the macrocell 10, It is possible to activate the function of the wireless LAN 25 by receiving the activation command of the wireless LAN 25 from the macro cell 10 through the backbone.

At this time, the macro cell terminal 100 or the wireless LAN 30 of the small cell 20 may be Wi-Fi. The wireless LAN link established through the wireless LAN 30 of the macro cell terminal 100 and the small cell 20 may be provided through a license-exempt band of LTE-U (LTE-Unlicensed) or Wi-Fi.

Next, the macro cell terminal 100 obtains access permission via the cellular link of the small cell 20 through the set wireless LAN link (S560). At this time, the small cell 20 can estimate the uplink interference level of the candidate macrocell terminal 100 through the connected WLAN link. That is, it is possible to share at least one of the strength of the interference of the uplink signal of the candidate macrocell terminal 100 and the access information of the macrocell 10 connected to the candidate macrocell terminal 100 through the wireless LAN link. In addition, the small cell 20 receives the information of the macro cell terminal 100 for authentication of the macro cell terminal 100 through the wireless LAN link, Various information can be exchanged to overcome signal interference.

The small cell 20 extracts the macro cell terminal 100 causing the uplink interference based on the information of the candidate macro cell terminal 100, permits access to the extracted macro cell terminal 100, And transmits information of the extracted macro cell terminal 100 to the macro cell 10. Accordingly, the macro cell 10 can handover the macro cell terminal 100 causing the uplink interference to the small cell 20.

Meanwhile, the macro cell terminal 100 can perform communication with the small cell 20 through the wireless LAN link and through the cellular link of the macro cell 10. That is, the macro cell terminal 100 can continue communication with the macro cell 10 before being handed over to the small cell 20.

When the macrocell terminal 100 acquires the access permission via the cellular link of the small cell 20 through the above process, the small cell 20 changes the service mode from the closed connection mode to the hybrid connection mode. The macro cell terminal 100 that has obtained the permission for the access mode of the small cell 20 is handed over to the small cell 20 that has obtained the access permission from the macro cell 10 (S570). When the service mode of the small cell 20 is changed, the macro cell terminal 100 transmits information indicating that the change of the service mode is completed from the small cell 20 through the cellular link or the wireless LAN link of the small cell 20 . Separately, the information indicating that the service mode of the small cell 20 has been changed can be transmitted to the macro cell 10 through the backhaul, and the macro cell 10 can transmit the macro cell 10 via the cellular link. Or may be transmitted to the cell terminal 100.

Meanwhile, the method for mitigating uplink signal interference according to an embodiment of the present invention is a method for mitigating uplink interference in a small cell 20 acquired through a cellular link of a small cell 20 to obtain an access permission through a cellular link of the small cell 20, Information of the small cell 20 is compared with the information of the wireless LAN 30 of the small cell 20 to determine whether the wireless LAN link is established with the small cell 20 receiving the uplink signal interference.

The macro cell terminal 100 first connects the wireless LAN 30 of the small cell 20 to the wireless LAN 30 of the small cell 20 in order to obtain the access permission of the small cell 20 through the cellular link, The information of the small cell 20 is acquired. Based on the information of the small cell 20 acquired through the cellular link of the small cell 20 and the information of the small cell 20 received via the wireless LAN link, the macro cell terminal 100 transmits the small cell 20 20 and the set wireless LAN link is set to the wireless LAN 30 of the small cell 20 which is interfered with the uplink signal. For example, the macro cell terminal 100 may transmit the information of the small cell 20 acquired through the cellular link of the small cell 20 and the information of the small cell 20 received through the wireless LAN 30 link It can be determined whether or not the small cell 20 and the set wireless LAN link are set to the wireless LAN 30 of the small cell 20 which is interfered with the uplink signal. At this time, the macro cell terminal 100 may acquire the information of the small cell 20 through the cellular link of the macro cell 10. In this case, the received information of the small cell 20 is transmitted to the macro cell 10 And information on the small cell 20 to be managed. When the macro cell terminal 100 determines that the set wireless LAN link is set to the wireless LAN of the small cell 20 receiving the interference of the uplink signal, the macro cell terminal 100 transmits the information to the small cell 20, 20) to obtain access permission through the wireless LAN link.

Alternatively, the macro cell terminal 100 may receive the small cell 20 information acquired through the cellular link of the small cell 20 and compare the received small cell 20 information. The macro cell terminal 100 transmits the information of the small cell 20 acquired through the cellular link of the small cell 20 to the small cell 20 to which the wireless LAN 30 link is set. The small cell 20 receives such information and determines whether the set wireless LAN link is set up with the macro cell terminal 100 causing the interference of the uplink signal. The macro cell terminal 100 determines And receives the result from the small cell 20. Based on such information, the macrocell terminal 100 confirms that the set wireless LAN link is set to the wireless LAN of the small cell 20 which is interfered with the uplink signal, and transmits it to the small cell 20 via the wireless LAN link It is possible to exchange information for access permission.

Hereinafter, with reference to FIG. 6, each component of the macro cell terminal 100 performed by the uplink signal interference mitigation method described with reference to FIG. 5 will be described.

6 is a block diagram of a macrocell terminal 100 according to an embodiment of the present invention.

The macro cell terminal 100 according to an exemplary embodiment of the present invention includes a cellular communication module 610, a wireless LAN communication module 620, a memory 630, and a processor 640.

6 may be implemented in hardware such as software or an FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and may perform predetermined roles can do.

However, 'components' are not meant to be limited to software or hardware, and each component may be configured to reside on an addressable storage medium and configured to play one or more processors.

Thus, by way of example, an element may comprise components such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, Routines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables.

The components and functions provided within those components may be combined into a smaller number of components or further separated into additional components.

The cellular communication module 610 according to the present invention transmits and receives data via the cellular link with the macro cell 10 or the small cell 20. The wireless LAN communication module 620 establishes a wireless LAN link with the wireless LAN of the small cell 20 to transmit and receive data. The wireless LAN communication module 620 may be implemented by a wireless LAN (WLAN), Bluetooth, HDR WPAN, UWB, ZigBee, Impulse Radio, 60 GHz WPAN, Binary-CDMA, wireless USB technology and wireless HDMI technology.

In the memory 630, a program for transmitting and receiving data to and from the macro cell 10 and the small cell 20 is stored. Here, the memory 630 is collectively referred to as a non-volatile storage device that keeps stored information even when power is not supplied. For example, the memory 630 may be a compact flash (CF) card, a secure digital (SD) card, a memory stick, a solid- A magnetic computer storage device such as a NAND flash memory, a hard disk drive (HDD) and the like, and an optical disc drive such as a CD-ROM, a DVD-ROM, etc. .

In addition, the program stored in the memory 630 may be implemented in hardware such as software or an FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and may perform predetermined roles.

The processor 640 executes the program stored in the memory 630. At this time, the processor 640 executes one or more small cells 20 existing around the macro cell terminal 100 through the cellular link of the small cell 20 connected by the cellular communication module 610, And transmits the obtained information of the at least one small cell 20 to the macro cell 10 through the cellular link of the macro cell 10. [ Specifically, the small cell 20 receiving the uplink signal interference by the macro cell terminal 100 requests interference management to the macro cell 10, and the macro cell 10 transmits the interference management request to the macro cell 10 And requests information on one or more small cells 20 existing around the macro cell terminal 100 to the terminal 100. Accordingly, the macro cell terminal 100 acquires the information of the at least one small cell 20 through the cellular link of the small cell 20, and transmits the information to the macro cell 10.

The macro cell terminal 100 can acquire the information of the small cell 20 through the cellular link of the macro cell 10. In this case, the received information of the small cell 20 is transmitted to the macro cell 10 And information on the small cell 20 to be managed. Accordingly, the macro cell terminal 100 can scan only the small cell 20 managed by the macro cell 10, rather than scanning all the small cells 20 existing in the vicinity thereof.

The macro cell 10 extracts the information of one or more candidate macrocell terminals 100 based on the information of the small cell 20 transmitted by the macrocell terminal 100, And transmits the information to the small cell 20. At the same time, the macro cell 10 transmits information of the at least one small cell 20 receiving the uplink signal interference to the at least one macro cell terminal 100, and accordingly, the macro cell terminal 100 transmits And receives the information of the small cell 20 which is interfered with the uplink signal.

The processor 640 activates the wireless LAN communication module 620 and establishes a wireless LAN link with the small cell 20 that is interfered with the uplink signal through the wireless LAN communication module 620. At this time, when the wireless LAN communication module 260 of the macro cell terminal 100 is already activated, it is not necessary to request another activation. And acquires access permission to the cellular link of the small cell 20 through the set wireless LAN link. At this time, the small cell 20 extracts the macrocell terminal 100 causing the uplink interference based on the information of the candidate macrocell terminal 100, and transmits this information to the macrocell 10. Then, the small cell 20 grants access to the small cell 20 on the basis of the extracted macro cell terminal 100.

At this time, the small cell 20 can estimate the uplink interference level of the candidate macrocell terminal 100 through the connected WLAN link. That is, it is possible to share at least one of the strength of the interference of the uplink signal of the candidate macrocell terminal 100 and the access information of the macrocell 10 connected to the candidate macrocell terminal 100 through the wireless LAN link. Based on such information, the small cell 20 extracts the macro cell terminal 100 causing the uplink interference, and grants access to the extracted macro cell terminal 100. That is, when the macro cell terminal 100 acquires the access permission of the small cell 20, the small cell 20 changes the service mode from the closed service mode to the hybrid service mode. The macro cell 10 transmits the macro cell terminal 100 to the small cell 20 which has received the access permission from the macro cell 10 based on the information of the macro cell terminal 100 transmitted from the small cell 20 Handover.

As described above, the uplink signal interference mitigation method induced from the macro cell terminal 100 and the macro cell terminal 100 according to the present invention is a method in which the macro cell terminal 100 transmits the uplink signal to the neighboring small cell 20 The mobile station 20 searches for a small cell 20 to control the interference to the small cell 20 and performs handover to the small cell 20 so that strong strong uplink signals Interference can be overcome.

In the handover to the small cell 20, access is permitted through the cellular link of the small cell 20 via the wireless LAN link with the small cell 20, The communication can be performed without releasing the connection, and the traffic load problem of the small cell 20 due to obtaining the access permission through the cellular link can be solved.

One embodiment of the present invention may also be embodied in the form of a computer program stored on a medium executed by a computer or a recording medium including instructions executable by the computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, the computer-readable medium may include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically includes any information delivery media, including computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transport mechanism.

While the methods and systems of the present invention have been described in connection with specific embodiments, some or all of those elements or operations may be implemented using a computer system having a general purpose hardware architecture.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

10: Macro cell
20, 20a, 20b, 20c: Small cell
21a, 21b, 21c, 21d: Small cell terminal
30: Wireless LAN
100: Macro cell terminal
610: cellular communication module
620: Wireless LAN communication module
630: Memory
640: Processor

Claims (17)

A method for mitigating uplink signal interference in a macro cell terminal,
Obtaining information of at least one small cell existing around the macro cell terminal through a cellular link of the small cell;
Transmitting information of the at least one small cell to the macro cell;
Receiving information on a small cell that is interfered with by the uplink signal from the macro cell;
Setting a wireless LAN link with a small cell that is interfered with by the uplink signal;
Acquiring an access permission to the cellular link of the small cell through the set wireless LAN link; and
And handover from the macro cell to the small cell in which the access mode is changed from the closed connection mode to the hybrid access mode. The method according to claim 1,
Wherein the macro cell transmits information of at least one small cell that is interfered with the uplink signal to one or more macro cell terminals,
Wherein the information of the small cell includes information on the ID of each of the one or more small cells and the current service mode. The method according to claim 1,
The small cell requests interference management of the uplink signal to the macro cell,
Wherein the macrocell transmits information of at least one candidate macrocell terminal that generates interference of the uplink signal to the small cell in response to the interference management request. The method of claim 3,
Wherein the macrocell requests information on one or more small cells existing in the vicinity of the macrocell terminal to the macrocell terminal in response to the interference management request, and based on the information of the at least one small cell received from the macrocell terminal And extracts the information of the candidate macro cell terminal. The method of claim 3,
Wherein the small cell extracts a macrocell terminal that causes the uplink interference based on the information of the candidate macrocell terminal,
Transmits information of the extracted macro cell terminal to a macro cell,
The step of handing over to the small cell in which the access mode is changed in the hybrid access mode,
Wherein the mobile station is handed over to the small cell that has obtained the access permission upon receipt of a handover command from the macro cell to the small cell. The method according to claim 1,
Wherein the information of the small cell further includes wireless LAN information of the small cell,
Wherein the wireless LAN information includes at least one of an SSID and a MAC address. The method according to claim 1,
Wherein the setting of the wireless LAN link with the small cell comprises:
And requesting activation of a small cell of the wireless LAN that is interfered with by the uplink signal. The method according to claim 1,
Wherein the macro cell terminal communicates with the small cell through the wireless LAN link and at the same time communicates with the macro cell. The method according to claim 1,
Wherein acquiring the access permission to the cellular link of the small cell includes:
Sharing at least one of an intensity of the uplink signal interference and access information of a macro cell connected to the macro cell terminal through the wireless LAN link;
And acquiring access permission from the small cell based on the shared information. The method according to claim 1,
Further comprising the step of receiving the change completion of the service mode from the small cell through the cellular link or the wireless LAN link of the small cell. The method according to claim 1,
Wherein the wireless LAN link is provided over a license-exempt band of LTE-U or Wi-Fi. The method according to claim 1,
Wherein the step of acquiring information of at least one small cell existing in the vicinity of the macro cell terminal comprises:
Acquiring information of the small cell through the cellular link of the macro cell,
Wherein the information of the small cell is information corresponding to a small cell managed by the macro cell. In the macro cell terminal,
Cellular communication module;
Wireless LAN communication module;
Memory in which programs for transmitting and receiving macro cells and small cells are stored, and
And a processor for executing the program,
As the processor executes the program,
Acquiring information of at least one small cell existing in the periphery of the macro cell terminal from the cellular link of the small cell through the cellular communication module and transmitting the information of the at least one small cell to the macro cell through the cellular link of the macro cell Receives information on a small cell which is interfered with an uplink signal from the macro cell,
Setting up a wireless LAN link with a small cell that is interfered with by the uplink signal through the wireless LAN communication module and acquiring access permission to the cellular link of the small cell through the set wireless LAN link,
Wherein the handover from the macro cell to the small cell in which the access mode is changed from the closed connection mode to the hybrid mode is performed. 14. The method of claim 13,
Wherein the processor shares at least one of an intensity of the uplink signal interference and access information of a macro cell connected to the macro cell terminal through the wireless LAN link established through the wireless LAN communication module,
And acquires an access permission from the small cell to the cellular link based on the shared information. 14. The method of claim 13,
The small cell requests interference management of the uplink signal to the macro cell,
Wherein the macrocell transmits information of at least one candidate macrocell terminal that generates interference of the uplink signal in response to the interference management request to the small cell. 16. The method of claim 15,
Wherein the macrocell requests information on one or more small cells existing in the vicinity of the macrocell terminal to the macrocell terminal in response to the interference management request, and based on the information of the at least one small cell received from the macrocell terminal And extracts information of the candidate macro cell terminal. 14. The method of claim 13,
Wherein the small cell extracts a macrocell terminal that causes the uplink interference based on the information of the candidate macrocell terminal,
Transmits information of the extracted macro cell terminal to a macro cell,
Wherein the macrocell handover the macro cell terminal causing the uplink interference to the small cell.

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