KR20150051143A - Method and apparatus for perceiving access between terminal and small cell - Google Patents

Method and apparatus for perceiving access between terminal and small cell Download PDF

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Publication number
KR20150051143A
KR20150051143A KR1020140140917A KR20140140917A KR20150051143A KR 20150051143 A KR20150051143 A KR 20150051143A KR 1020140140917 A KR1020140140917 A KR 1020140140917A KR 20140140917 A KR20140140917 A KR 20140140917A KR 20150051143 A KR20150051143 A KR 20150051143A
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KR
South Korea
Prior art keywords
base station
small base
message
small
terminal
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KR1020140140917A
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Korean (ko)
Inventor
양미정
임순용
정광렬
신재욱
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한국전자통신연구원
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Priority to US14/520,913 priority Critical patent/US20150119048A1/en
Publication of KR20150051143A publication Critical patent/KR20150051143A/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2603—Arrangements for wireless physical layer control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/32—Hierarchical cell structures

Abstract

The present invention relates to a method and a device for perceiving access between a small cell and a terminal. A macro base station transmits a request message for adding or modifying a small cell to a small base station being accessed by a terminal and transmits a message for access to the small base station to the terminal if a response message is received from the small base station. Afterwards, the macro base station obtains the result of the access between the terminal and the small base station and determines whether or not the terminal accesses the small base station based on the obtained results.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for recognizing connection between a small cell and a terminal,

The present invention relates to a method and apparatus for a macro base station to recognize a connection between a small cell and a terminal.

The base station can be classified into macro, pico, and femto base stations according to the size of the coverage area. The macro base station is a base station that can be used to cover a wider area than a Pico or Femto base station. 3GPP (3rd Generation Partnership Project) refers to a Pico or Femto base station as a small cell. A small cell represents a cell having a low transmission power and a narrow coverage compared to a macrocell having a high transmission power and a wide coverage. Therefore, generally, for example, a 10 W or less small power base station equipment, a pico cell, and a femtocell are included per antenna

Various schemes are being studied to more efficiently use the network in a network environment where a macro base station and a small base station are mixed. In such a network situation, a mobile communication system is studying a small cell enhancement technology to effectively accommodate a rapidly increasing data traffic.

In the small cell performance enhancement technique, macro cells with wide coverage and small cells overlapping with macro cells are concentrated to disperse traffic. At this time, the terminal maintains dual connectivity to macro cells and small cells, and provides performance improvement by inter-node resource aggregation between macrocells and small-cell nodes.

The dual access is a transmission scheme in which the UE can simultaneously use the radio resources provided by the macro base station and the small base station to increase the transmission efficiency. The flow of only a part of the traffic of the terminal to the small cell while maintaining the double connection implies that the terminal does not perform the inter-cell handover as though the terminal is overlapped with the macro cell and the small cell. Therefore, a new method for off-loading data with a small cell is required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a connection recognition method and apparatus capable of effectively distributing traffic from a macro base station to a small base station in a network environment in which a macro base station and a small base station are mixed.

A method of recognizing a connection according to an aspect of the present invention includes transmitting a small cell addition / change request message to a small base station in which the macro base station enters a terminal in a connection recognition method in a network environment in which a macro base station and a small base station are mixed ; Transmitting a message for connection to the small base station to the mobile station when the macro base station receives a response message from the small base station; The macro base station acquiring a result of connection between the terminal and the small base station; And determining whether the connection between the mobile station and the small base station is completed based on the obtained result.

Wherein the step of acquiring the result receives a small cell access status message including a result of random access from the terminal to the small base station, and the determining step includes a step of, when the random access result included in the small- If it indicates success, it can be recognized that the connection between the terminal and the small base station is established.

Wherein the step of transmitting a message for the connection comprises transmitting an RRC connection reconfiguration message to the UE, and the step of acquiring the result comprises performing radio resource control (RRC) reconfiguration (RRC) including a result of random access from the UE to the small base station A completion message can be received.

The determining step may determine whether the UE and the small base station are connected based on a random access result included in the RRC connection reconfiguration completion message received after the random access procedure of the UE and the small base station.

The connection acknowledgment method may further comprise: after the step of transmitting a message for connection to the small base station to the terminal, the terminal configures resources according to the contents of the message for the connection, Performing random access to the data; And transmitting a message including the random access result to the macro base station when the MS receives a response message including timing information from the small base station according to the random access.

Meanwhile, the step of acquiring the result may include receiving a small cell status message including a random access result of the UE from the small base station, and the step of determining may include determining that the random access result included in the small cell status message is a connection success It can be recognized that the connection between the terminal and the small base station is established.

In this case, the connection acknowledgment method may further comprise: after the step of transmitting a message for connection to the small base station to the terminal, the terminal configures resources according to the contents of the message for the connection, Performing random access to the data; Receiving a response message including timing information and uplink grant information (UL grant) from the small base station according to the random access; And transmitting the random access message to the small base station based on the uplink grant information.

Here, when the random access message is transmitted from the terminal to the small base station, the small cell status message may be received from the small base station to the macro base station.

In addition, the step of acquiring the result may include receiving an uplink data packet transmitted from the mobile station from the small base station, and determining that the connection is established between the mobile station and the small base station when receiving the uplink data packet .

In this case, the connection recognition method may further comprise: after the step of transmitting a message for connection to the small base station to the terminal, the terminal configures resources according to the content of the message for the connection, Performing random access to the base station; And transmitting the uplink data packet to the small base station when the mobile station receives the response message including the timing information from the small base station according to the random access.

In addition, the step of acquiring the result may include receiving an RRC connection reconfiguration completion message from the small base station, and determining that the connection is established between the mobile station and the small base station when receiving the RRC connection reconfiguration completion message from the small base station .

Herein, the step of transmitting a message for connection to the small base station to the terminal may transmit an RRC connection reconfiguration message including Signaling Radio Bearer (SRB) information for signal transmission to the small base station.

The RRC connection reconfiguration completion message received from the small base station may include an RRC connection reconfiguration completion message transmitted to the small base station according to the SRB of the MS when the uplink synchronization between the MS and the small base station is completed, It may be a message delivered to the base station.

The connection recognition method further includes performing a subsequent procedure including traffic control between the terminal and the small base station when the connection between the terminal and the small base station is successfully performed after the determining step can do.

The connection acknowledgment method may further include a step of transmitting the response message to the macro base station when the small base station can accept the request content included in the small cell addition request message after transmitting the small cell addition / As shown in FIG.

According to another aspect of the present invention, there is provided a connection recognition apparatus comprising: a radio frequency transceiver for transmitting and receiving signals through an antenna in a connection recognition apparatus in a network environment in which a macro base station and a small base station are mixed, And a connection of the small base station, wherein the processor transmits a small cell addition / change request message to the small base station to which the terminal enters, and upon receiving a response message from the small base station, A small cell addition / change processing unit for transmitting a message for connection to the small cell; A connection result obtaining unit for obtaining a result of connection between the mobile station and the small base station and determining whether the mobile station is connected to the small base station based on the obtained result; And a subsequent procedure processor for performing a subsequent procedure including traffic control when a connection between the terminal and the small base station is established.

Wherein the connection result acquiring unit receives a small cell access status message including a result of a random access success from the UE to the small base station, the RRC including a result of random access from the UE to the small base station, When receiving a connection reconfiguration completion message, receiving a small cell status message including a result of random access success of the UE from the small base station, and receiving a UL data packet transmitted from the small base station , And receiving the RRC connection reconfiguration complete message from the small base station, it can be determined that the connection between the mobile station and the small base station has been successfully performed.

When receiving the small cell status message, the UE receives a response message including timing information and UL grant information from the small base station, and transmits a random access message based on the uplink grant information to the small And may indicate receiving the small cell status message from the small base station when transmitting to the base station.

When receiving the RRC connection reconfiguration completion message from the small base station, the MS receives an RRC connection reconfiguration message including Signaling Radio Bearer (SRB) information for signaling with the small base station, The RRC connection reconfiguration completion message transmitted to the small base station according to the SRB of the MS may be transmitted to the macro base station.

According to the embodiment of the present invention, in a network environment where a macro base station and a small base station are mixed, the macro base station can recognize that the connection procedure between the terminal and the small base station has been successfully completed. After the connection procedure is recognized, the macro base station can control the traffic between the small base station and the mobile station. Therefore, traffic control for switching the bearer that has passed through the macro base station to the small base station from the macro base station to the small base station becomes possible without packet loss. As a result, traffic performance can be further improved in small cell enhancement techniques.

Also, when inter-node resource aggregation is provided, the macro base station can connect the terminal to the newly discovered small base station and effectively distribute the traffic.

1 is a diagram illustrating a network environment according to an embodiment of the present invention.
2 is a flowchart of a small cell addition procedure performed by a macro base station for providing a dual connection.
3 is a flowchart of a method in which a macro base station recognizes connection between a small cell and a terminal according to the first embodiment of the present invention.
4 is a flowchart of a method in which a macro base station recognizes a connection between a small cell and a terminal according to a second embodiment of the present invention.
5 is a flowchart of a method in which a macro base station recognizes a connection between a small cell and a terminal according to a third embodiment of the present invention.
6 is a flowchart of a method in which a macro base station recognizes connection between a small cell and a terminal according to a fourth embodiment of the present invention.
7 is a flowchart of a method in which a macro base station recognizes a connection between a small cell and a terminal according to a fifth embodiment of the present invention.
8 is a diagram illustrating a structure of a connection recognition apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, 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 an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Throughout the specification, a terminal is referred to as a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (HR- A subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a user equipment (UE) , HR-MS, SS, PSS, AT, UE, and the like.

Also, a base station (BS) is an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) (RS), a relay node (RN) serving as a base station, an advanced relay station (ARS) serving as a base station, a high reliability relay station (HR) A femto BS, a home Node B, a HNB, a pico BS, a metro BS, a micro BS, ), Etc., and may be all or part of an ABS, a Node B, an eNodeB, an AP, a RAS, a BTS, an MMR-BS, an RS, an RN, an ARS, It may include a negative feature.

Hereinafter, a method for recognizing a connection between a small cell and a terminal according to an embodiment of the present invention and an apparatus therefor will be described with reference to the drawings.

1 is a diagram illustrating a network environment according to an embodiment of the present invention.

1, the macro base station 1 and the small base station 2 provide services to the terminal 3 in a network environment in which a macro cell and a small cell are mixed with each other . The macro base station 1 and the small base station 2 may be connected via a non-ideal backhaul 4.

When the terminal 3 receiving a service from the macro base station 1 (which may be called a MeNB (Master eNB)) enters a new small cell, the macro base station 1 transmits the terminal 3 to the small base station 2 (Which may be called a SeNB (Secondary eNB)), it instructs the terminal 3 to set a new bearer in addition to the bearer (radio bearer or EPS bearer) in the existing macro cell. Accordingly, the terminal 3 forms dual connectivity with the macro base station 1 and the small base station 2. Here, the terminal 3 is provided with major control of the control plane through the macro base station 1, and data is provided from the two base stations. Since the macro base station 1 provides the frequency resource F1 and the small base station 2 provides the frequency resource F2 to the terminal 3, Can be transmitted to the terminal 3 through the frequency resource F1 of the small base station 2 and through the frequency resource F2 of the small base station 2.

The procedure for providing such a double connection may be referred to as a small cell addition or a change procedure.

2 is a flowchart of a small cell addition procedure performed by a macro base station for providing a dual connection.

2, when the terminal 3 enters a new small cell, the macro base station 1 requests the addition / change processing to the small base station 2 of the corresponding small cell and receives a response (S100 ).

Thereafter, bearer setup with the small cell is instructed to the terminal 3, and the bearer for communication is established between the small base station 2 and the terminal 3. For example, when the small base station 2 receives a bearer setup request message including bearer-related information from the terminal 2, it creates a bearer, maps the corresponding bearer to the generated bearer, (RRC) reconnection message to the terminal 3 (S110). Then, the terminal 3 transmits a message (for example, an RRC Connection Reconfiguration Complete message) to the small base station 2 for bearer activation according to the received message (S120) The RRC connection reconfiguration completion message is received from the terminal 3. The bearer activation is performed by the RRC connection reconfiguration completion message from the terminal 3. The small base station 2 and the terminal 3 establish bearer for communication.

Thereafter, the terminal 3 performs a random access procedure with the small base station 2 (S130), and the connection between the terminal 3 and the small base station 2 is completed. After the random access procedure is successfully completed, the macro base station 1 can control the traffic between the small base station 2 and the terminal 3 (S140).

The traffic control indicates that the macro base station performs a path switch to a bearer that has passed through a split or macro base station for the same bearer to a small base station. This traffic control is dependent on the structure of the data plane in the small cell enhancement technique. Controlling the traffic between the small base station and the mobile station in the macro base station can be prevented after the connection between the small base station and the mobile station is completed.

In the embodiment of the present invention, while performing the small cell addition / change procedure as described above, the macro base station recognizes the connection between the small base station and the terminal.

In the procedure of SeNB addition or SeNB change, the macro base station obtains the random access result between the terminal and the small base station, and this random access result acquisition procedure can be performed as follows.

One. Procedure A: A procedure in which a mobile station receiving a response to a physical random access channel (PRACH) transmits a small cell access status message (SeNB access status message) to a macro base station

2. Procedure B: A procedure in which the MS receiving the response to the PRACH transmits an RRC connection reconfiguration complete message to the macro base station

3. Procedure C: A procedure in which the small base station receiving the random access message (RA message # 3) transmits a small cell status message (SeNB status message) to the macro base station

4. Procedure D: The case where the macro base station receives the uplink data packet (UL data packet) is a procedure that the macro base station recognizes the base station as a random access result between the terminal and the small base station

5. Procedure E: Procedure for transmitting RRC connection reconfiguration complete message (RRC connection reconfiguration complete message) to the macro base station through the path through the small base station (SeNB route)

In the embodiment of the present invention, the macro base station recognizes the connection completion between the small base station and the mobile station based on the random access result acquisition procedure based on various procedures (procedures A to E) as described above.

3 is a flowchart of a method in which a macro base station recognizes connection between a small cell and a terminal according to the first embodiment of the present invention.

In the first embodiment of the present invention, the macro base station recognizes the connection of the small cell and the terminal based on the procedure A based random access result acquisition procedure.

3, when the terminal 3 enters a new small cell, the macro base station 1 determines whether to add a small cell or change a small cell (S300). If the small base station 2 (Addition / change) process and receives a response.

The macro base station 1 transmits a small cell addition request message (SeNB Addition Request) to the corresponding small base station 2 (S310).

When receiving the small cell addition request message (SeNB Addition Request), the small base station 2 compares its capability with the message content, and if it is acceptable to accept the request, transmits a small cell addition response message (SeNB Addition Ack) 1 (S320, S330). The small base station 2 constructs resources according to the content of the request.

The macro base station 1 receives the Small Cell Addition Response message (SeNB Addition Ack) and transmits an RRC Connection Reconfiguration message to the UE 3 (S340).

The terminal 3 constructs resources according to the contents of the RRC connection reconfiguration message and transmits a RRC Connection Reconfiguration Complete message to the macro base station 1 when the resource configuration is completed (S350).

Thereafter, as a result of resource configuration, the terminal 3 transmits a PRACH to the small base station 2 (S360). Here, the RRC connection reconfiguration completion message is transmitted and the PRACH is transmitted, but the present invention is not limited thereto. Since the PRACH transmission is made up of a small base station, there is no subsequent relationship between the timing of transmitting the RRC connection reconfiguration completion message and the timing of transmitting the PRACH.

The small base station 2 having received the PRACH for synchronization from the terminal 3 transmits a response message to the terminal 3 (S370). The small base station 2 uses a Random Access Response (RAR) message or a TA (Timing Alignment) message as a response message to PRACH reception. The response message includes information for adjusting the uplink transmission timing between the UE and the small base station.

Uplink synchronization with the small base station 2 is completed as the terminal 3 receives the timing information included in the response message of the PRACH and the terminal 3 determines that the random access (RA) is successful. Then, the terminal 3 transmits the result of the success of the RA to the macro base station 1 (S380). In the embodiment of the present invention, the terminal 3 transmits the RA result to the macro base station 1 using the small cell access status message (SeNB Access Status).

The macro base station 1 recognizes the connection between the mobile station and the small base station based on the message received after the RA procedure of the mobile station and the small base station. Specifically, when the small cell access status message received from the terminal 3 indicates an RA failure, the macro base station 1 interrupts the small cell addition (SeNB addition) or the small cell change (SeNB change) The procedure is repeated. On the other hand, if the small cell access status message indicates RA success, the macro base station 1 proceeds to the subsequent procedure.

In this manner, the macro base station 1 recognizes the connection between the small cell and the terminal based on the small cell access status message (SeNB Access Status) transmitted from the terminal that has received the response to the PRACH, and proceeds with the subsequent procedure (S390 ). After confirming that the RA of the UE has been successfully completed, the macro base station 1 controls the traffic between the small base station and the UE in a subsequent procedure. For example, traffic control is performed to route the bearer from the macro base station to the small base station via the split or macro base station for the same bearer to the small base station. This traffic control is performed after it is recognized that the connection between the MS and the small base station has been successfully completed, thereby preventing packet loss.

4 is a flowchart of a method in which a macro base station recognizes a connection between a small cell and a terminal according to a second embodiment of the present invention.

In the second embodiment of the present invention, the macro base station recognizes the connection of the small cell and the terminal based on the procedure B-based random access result acquisition procedure.

4, when the terminal 3 enters a new small cell, the macro base station 1 determines whether to add a small cell or a small cell (S500), and determines whether the small base station 2 (Addition / change) process and receives a response.

The macro base station 1 transmits a small cell addition request message (SeNB Addition Request) to the corresponding small base station 2 (S510).

When receiving the small cell addition request message (SeNB Addition Request), the small base station 2 compares its capability with the message content, and if it is acceptable to accept the request, transmits a small cell addition response message (SeNB Addition Ack) 1) (S520, S530). The small base station 2 constructs resources according to the content of the request.

The macro base station 1 receives the small cell addition response message (SeNB Addition Ack) and transmits an RRC Connection Reconfiguration message (RRC Connection Reconfiguration) to the UE 3 (S540).

The terminal 3 constructs resources according to the contents of the RRC connection reconfiguration message and the terminal 3 transmits the PRACH to the small base station 2 as a result of the resource configuration at operation S550.

The small base station 2 having received the PRACH for synchronization from the terminal 3 transmits a response message to the terminal 3 (S560). The small base station 2 uses a RAR message or a TA message as a response message to PRACH reception. The response message includes information for adjusting the uplink transmission timing between the UE and the small base station.

Uplink synchronization with the small base station 2 is completed as the terminal 3 receives the timing information included in the response message of the PRACH, and the terminal 3 determines that the RA is successful. Then, the terminal 3 transmits the RA result to the macro base station 1. In the second embodiment of the present invention, the terminal 3 transmits the RA result to the macro base station 1 using an RRC Connection Reconfiguration Complete message (S570).

The macro base station 1 determines whether the RRC connection reconfiguration completion message received from the terminal 3 after the RA procedure of the terminal and the small base station indicates an RA failure or a small cell addition (SeNB addition) or a small cell change SeNB change) procedure and return to the initial configuration state. On the other hand, if the RRC connection reconfiguration completion message indicates RA success, the macro base station 1 proceeds to the subsequent procedure (S580).

In this manner, the macro base station 1 recognizes the connection of the MS based on the RRC Connection Reconfiguration Complete (RRC Connection Reconfiguration Complete) transmitted from the MS that has received the response to the PRACH, and proceeds with the subsequent procedure.

5 is a flowchart of a method in which a macro base station recognizes a connection between a small cell and a terminal according to a third embodiment of the present invention.

In the third embodiment of the present invention, the macro base station recognizes the connection of the small cell and the terminal based on the procedure C based random access result acquisition procedure.

5, when the terminal 3 enters a new small cell, the macro base station 1 determines whether to add a small cell or change a small cell (S700), and transmits the small cell to the small base station 2 (Addition / change) process and receives a response.

The macro base station 1 transmits a small cell addition request message (SeNB Addition Request) to the corresponding small base station 2 (S710).

When receiving the small cell addition request message (SeNB Addition Request), the small base station 2 compares its capability with the message content, and if it is acceptable to accept the request, transmits a small cell addition response message (SeNB Addition Ack) 1 (S720, S730). The small base station 2 constructs resources according to the content of the request.

The macro base station 1 receives the Small Cell Addition Response message (SeNB Addition Ack) and transmits an RRC Connection Reconfiguration message (RRC Connection Reconfiguration) to the MS 3 (S740).

The terminal 3 constructs resources according to the contents of the RRC connection reconfiguration message, and transmits the RRC Connection Reconfiguration Complete message to the macro base station 1 when the resource configuration is completed (S750).

Thereafter, as a result of the resource configuration, the terminal 3 transmits a PRACH to the small base station 2 (S760). There is no subsequent relationship between the timing of transmitting the above RRC reconfiguration complete message and the timing of transmitting the PRACH.

The small base station 2 having received the PRACH for synchronization from the terminal 3 transmits a response message to the terminal 3 (S770). The small base station 2 uses the RAR message as a response message to the PRACH reception. The response message includes information for adjusting uplink transmission timing between the UE and the small base station, and includes UL grant information for a random access message (RA message # 3). If the RA fails to receive the RAR message and the RA fails, the terminal 3 stops the small cell addition or small cell change procedure and performs a procedure of returning to the initial configuration state.

Uplink synchronization with the small base station 2 is completed as the terminal 3 receives the timing information included in the response message of the PRACH, and the terminal 3 determines that the RA is successful. The terminal 3 transmits a random access message (RA message # 3) to the small base station 2 on the basis of UL grant information for the random access message (RA message # 3) included in the response message of the PRACH (S780).

When the small base station 2 receives the random access message (RA message # 3) from the terminal 3, it determines that the RA of the terminal is successful and transmits a small cell status message (SeNB Status) to the macro base station 1 S790). In the third embodiment of the present invention, the result of RA success is reported to the macro base station using a small cell status message (SeNB Status message).

The macro base station 1 determines whether the small cell status message (SeNB Status) received from the small base station 2 after the RA procedure of the terminal and the small base station 2 indicates an RA failure, The procedure to stop the small cell change (SeNB change) procedure and return to the initial configuration state is performed. On the other hand, if the small cell status message (SeNB Status) indicates the success of the RA, the macro base station 1 proceeds to the subsequent procedure (S800).

In this manner, the macro base station 1 recognizes the connection of the MS based on the small cell status message (SeNB Status) from the small base station, which is a message received after the RA procedure of the MS and the small base station, and proceeds with the subsequent procedure.

6 is a flowchart of a method in which a macro base station recognizes connection between a small cell and a terminal according to a fourth embodiment of the present invention.

In the fourth embodiment of the present invention, the macro base station recognizes the connection of the small cell and the terminal based on the procedure D based random access result acquisition procedure.

6, when the terminal 3 enters a new small cell, the macro base station 1 determines whether to add a small cell or a small cell (S900). If the small base station 2 (Addition / change) process and receives a response.

The macro base station 1 transmits a small cell addition request message (SeNB Addition Request) to the corresponding small base station 2 (S910).

When receiving the small cell addition request message (SeNB Addition Request), the small base station 2 compares its capability with the message content, and if it is acceptable to accept the request, transmits a small cell addition response message (SeNB Addition Ack) 1 (S920, S930). The small base station 2 constructs resources according to the content of the request.

The macro base station 1 receives the small cell addition acknowledgment message (SeNB Addition Ack) and transmits an RRC Connection Reconfiguration message (RRC Connection Reconfiguration) to the UE 3 (S940).

When the resource configuration is completed, the terminal 3 transmits an RRC Connection Reconfiguration Complete message to the macro base station 1 (S950).

Thereafter, as a result of resource configuration, the terminal 3 transmits a PRACH to the small base station 2 (S960). There is no subsequent relationship between the timing of transmitting the above RRC reconfiguration complete message and the timing of transmitting the PRACH.

The small base station 2 having received the PRACH for synchronization from the terminal 3 transmits a response message to the terminal 3 (S970). The small base station 2 uses a RAR message or a TA message as a response message to PRACH reception. The response message includes information for adjusting the uplink transmission timing between the UE and the small base station. Here, if the RA fails in receiving the RAR message, the terminal 3 stops the small cell addition or small cell change procedure and performs a procedure of returning to the initial configuration state.

Uplink synchronization with the small base station 2 is completed as the terminal 3 receives the timing information included in the response message of the PRACH, and the terminal 3 determines that the RA is successful. Thereafter, the terminal 3 transmits an UL data packet to the small base station 2 (S980). The small base station 2 transmits the uplink data packet received from the terminal 3 to the macro base station 1 (S990).

When the macro base station 1 receives the data received after the RA procedure of the terminal and the small base station, that is, the uplink data packet transmitted by the terminal 3 from the small base station 2, the macro base station 1 determines that the RA procedure of the terminal is successful, The following procedure is performed (S1000). If the uplink data packet transmitted from the small base station 2 is not transmitted, the macro base station 1 regards the RA as failed and performs a small cell addition (SeNB addition) or a small cell change (SeNB change) procedure And return to the initial configuration state.

As described above, when the UE receives the UL packet arrival (UL data arrival) after the RA procedure of the terminal and the small base station, the macro base station 1 recognizes the connection to the small base station of the terminal and proceeds with the subsequent procedure.

7 is a flowchart of a method in which a macro base station recognizes a connection between a small cell and a terminal according to a fifth embodiment of the present invention.

In the fifth embodiment of the present invention, the macro base station recognizes the connection of the small cell and the terminal based on the procedure E based random access result acquisition procedure.

7, when the terminal 3 enters a new small cell, the macro base station 1 determines whether to add a small cell or change a small cell (S1100), and determines whether the small base station 2 (Addition / change) process and receives a response.

The macro base station 1 transmits a small cell addition request message (SeNB Addition Request) to the corresponding small base station 2 (S1110).

When receiving the small cell addition request message (SeNB Addition Request), the small base station 2 compares its capability with the message content, and if it is acceptable to accept the request, transmits a small cell addition response message (SeNB Addition Ack) 1 (S1120, S1130). The small base station 2 constructs resources according to the content of the request.

The macro base station 1 receives the small cell addition response message (SeNB Addition Ack) and transmits an RRC Connection Reconfiguration message (RRC Connection Reconfiguration) to the UE 3 (S1140). According to an embodiment of the present invention, the macro base station 1 includes information for setting up a radio bearer for signal transmission with a small base station to the configuration resource information of the RRC connection reconfiguration message. Specifically, SRB (Signaling Radio Bearer) information for signal transmission to a small base station is included. Then, an RRC Connection Reconfiguration Complete message is transmitted to the small base station through the SRB. For this purpose, the RRC Connection Reconfiguration Complete message is requested to the SRB according to the RRC.

The terminal 3 constructs resources according to the contents of the RRC connection reconfiguration message, and transmits the PRACH to the small base station 2 when the resource configuration is completed (S1150).

The small base station 2 having received the PRACH for synchronization from the terminal 3 transmits a response message to the terminal 3 (S1160). The small base station 2 uses the RAR message as a response message to the PRACH reception. The response message includes information for adjusting the uplink transmission timing between the UE and the small base station. Uplink synchronization with the small base station 2 is completed as the terminal 3 receives the timing information included in the response message of the PRACH, and the terminal 3 determines that the RA is successful. Then, the terminal 3 transmits an RRC Connection Reconfiguration Complete message to the small base station 2 according to the SRB (S1170). Here, if the RA 3 fails to receive the RAR message or fails to transmit the RRC connection reconfiguration completion message, the RA 3 stops the small cell addition or small cell change procedure and returns to the initial configuration state.

The small base station 2 receives the RRC Connection Reconfiguration Complete message from the terminal 3 and delivers the received RRC Connection Reconfiguration Complete message to the macro base station 1 ).

When the macro base station 1 receives the data received after the RA procedure of the MS and the small base station, that is, the RRC Connection Reconfiguration Complete message from the small base station 2, it determines that the RA procedure of the MS is successful , And a subsequent procedure is performed (S1190). If the RRC Connection Reconfiguration Complete message is not transmitted from the small base station 2 to the macro base station 1, the macro base station 1 regards the RA as failed and performs a small cell addition (SeNB addition) or a small cell change (SeNB change) procedure And return to the initial configuration state.

In this manner, when the macro base station 1 receives the RRC connection reconfiguration completion message from the small base station after the RA procedure of the mobile station and the small base station, the macro base station 1 recognizes the connection to the small base station of the mobile station and proceeds with the subsequent procedure.

8 is a diagram illustrating a structure of a connection recognition apparatus according to an embodiment of the present invention.

As shown in FIG. 8, the connection recognition apparatus 100 includes a processor 110, a memory 120, and a radio frequency (RF) converter 130. The processor 110 may be configured to implement the procedures and methods described above with reference to Figures 3-7.

To this end, the processor 110 includes a small cell addition / modification processing unit 111, a connection result obtaining unit 112, and a subsequent procedure processing unit 113.

When the small cell addition / change processing unit 111 transmits a small cell addition / change request message to the small base station to which the terminal is entering and receives a response message for the small cell addition / change request message from the small base station, (RRC connection reconfiguration message) for connection to the RRC connection.

The connection result acquiring unit 112 acquires a result of connection between the terminal and the small base station. The connection result acquiring unit 112 acquires a random access result based on various procedures (procedures A to E) as described above. That is, when receiving the small cell access status message including the RA result from the mobile station to the small base station, if the RA result included in the small cell access status message indicates the connection success, it is recognized that the connection between the mobile station and the small base station is established. Or receives an RRC connection reconfiguration completion message including an RA result from the UE to the small base station, and recognizes whether the UE and the small base station are connected based on the random access result included in the RRC connection reconfiguration completion message. Or receives a small cell status message including the RA result of the terminal from the small base station, and recognizes that the connection between the terminal and the small base station is established when the RA result included in the small cell status message indicates connection success. Alternatively, upon receiving the uplink data packet transmitted from the terminal from the small base station, it is recognized that the connection between the terminal and the small base station is established. Or receives the RRC connection reconfiguration completion message from the small base station, it is recognized that the connection between the mobile station and the small base station is established.

The subsequent procedure processing unit 113 performs a subsequent procedure after it is recognized that the connection between the terminal and the small base station has been successfully completed. Specifically, the traffic between the small base station and the mobile station is controlled, and traffic control is performed after it is recognized that the connection between the mobile station and the small base station has been successfully completed, thereby preventing packet loss.

The memory 120 is coupled to the processor 110 and stores various information related to the operation of the processor 110. [ The RF converter 130 is connected to the processor 110 and transmits or receives a radio signal, and in particular, can transmit and receive signals using multiple antennas.

The embodiments of the present invention are not limited to the above-described apparatuses and / or methods, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (19)

In a connection recognition method in a network environment in which a macro base station and a small base station are mixed,
The macro base station transmitting a small cell addition / change request message to a small base station to which the mobile station enters;
Transmitting a message for connection to the small base station to the mobile station when the macro base station receives a response message from the small base station;
The macro base station acquiring a result of connection between the terminal and the small base station; And
Determining whether connection between the mobile station and the small base station is completed based on the obtained result
Lt; / RTI > The method of claim 1, wherein
Wherein the step of obtaining the result includes receiving a small cell access status message including a result of random access from the terminal to the small base station,
Wherein the determining step determines that a connection is established between the terminal and the small base station if the random access result included in the small cell access status message indicates a connection success. The method of claim 1, wherein
Wherein the step of transmitting a message for the connection comprises transmitting an RRC connection reconfiguration message to the terminal,
And the step of acquiring the result receives a radio resource control (RRC) connection reconfiguration completion message including a random access result from the terminal to the small base station. The method of claim 3, wherein
Wherein the determining step determines whether the UE and the small base station are connected based on a random access result included in the RRC connection reconfiguration completion message received after the random access procedure of the UE and the small base station. The method according to any one of claims 2 to 4, wherein
After the step of transmitting a message for connection to the small base station to the terminal,
The UE configuring resources according to the contents of the message for connection, and the UE performing random access to the small base station; And
Transmitting a message including the random access result to the macro base station when the mobile station receives a response message including timing information from the small base station according to the random access;
Further comprising the steps of: The method of claim 1, wherein
Wherein the step of acquiring the result comprises: receiving a small cell status message including a random access result of the terminal from the small base station,
Wherein the determining step determines that a connection is established between the terminal and the small base station if the random access result included in the small cell status message indicates a connection success. The method of claim 6, wherein
After the step of transmitting a message for connection to the small base station to the terminal,
The UE configuring resources according to the contents of the message for connection, and the UE performing random access to the small base station;
Receiving a response message including timing information and uplink grant information (UL grant) from the small base station according to the random access; And
And transmitting the random access message to the small base station based on the uplink grant information
Further comprising the steps of: The method of claim 7, wherein
Wherein the small cell status message is received from the small base station to the macro base station when the random access message is transmitted from the terminal to the small base station. The method according to claim 1,
The step of acquiring the result may include receiving an uplink data packet transmitted from the mobile station from the small base station,
Wherein the determining step determines that the connection between the mobile station and the small base station is established upon receiving the uplink data packet. The method of claim 9, wherein
After the step of transmitting a message for connection to the small base station to the terminal,
The UE configuring resources according to the contents of the message for connection, and the UE performing random access to the small base station;
When the MS receives a response message including timing information from the small base station according to the random access, transmitting the uplink data packet to the small base station
Further comprising the steps of: The method of claim 1, wherein
Wherein the step of acquiring the result includes receiving an RRC connection reconfiguration completion message from the small base station,
Wherein the determining step recognizes that the connection between the UE and the small base station is established upon receiving the RRC connection reconfiguration completion message from the small base station. The method of claim 11, wherein
Wherein the step of transmitting a message for connection to the small base station transmits an RRC connection reconfiguration message including Signaling Radio Bearer (SRB) information for signal transmission to the small base station. The method of claim 12, wherein
The RRC connection reconfiguration completion message received from the small base station may include an RRC connection reconfiguration completion message transmitted to the small base station according to the SRB of the MS when the uplink synchronization between the MS and the small base station is completed, A message delivered to the base station. The method of claim 1, wherein
After the determining step
Further comprising performing a subsequent procedure including traffic control between the terminal and the small base station when the connection between the terminal and the small base station is successfully performed. The method of claim 1, wherein
After transmitting the small cell addition / change request message,
Further comprising the step of transmitting the response message to the macro base station when the small base station is able to accept the request content included in the small cell addition request message. In a connection recognition apparatus in a network environment in which a macro base station and a small base station are mixed,
A radio frequency converter for transmitting and receiving signals through an antenna, and
And a process of being connected to the radio frequency converter and processing whether the connection is made between the terminal and the small base station,
The processor comprising:
A small cell addition / change processing unit for transmitting a small cell addition / change request message to a small base station to which the mobile station enters and for transmitting a message for connection to the small base station to the mobile station when receiving a response message from the small base station;
A connection result obtaining unit for obtaining a result of connection between the mobile station and the small base station and determining whether the mobile station is connected to the small base station based on the obtained result; And
A subsequent procedure processing unit for performing a subsequent procedure including traffic control when a connection between the terminal and the small base station is established,
And a connection identifier. The method of claim 16, wherein
The connection result obtaining unit
When receiving a small cell access status message including a result of random access success from the terminal to the small base station,
When receiving a radio resource control (RRC) reconfiguration completion message including a result of a random access success from the UE to the small base station,
When receiving a small cell status message including a result of random access success of the UE from the small base station,
When receiving the uplink data packet transmitted from the mobile station from the small base station,
When receiving the RRC connection reconfiguration completion message from the small base station
Lt; RTI ID = 0.0 >
And determines that the connection between the terminal and the small base station has been successfully performed. The method of claim 17, wherein
When receiving the small cell status message,
When the mobile station receives a response message including timing information and UL grant information from the small base station and transmits a random access message to the small base station based on the uplink grant information, Wherein the small cell status message indicates to receive the small cell status message. The method of claim 17, wherein
When the RRC connection reconfiguration completion message is received from the small base station,
When the MS receives an RRC connection reconfiguration message including Signaling Radio Bearer (SRB) information for signal transmission to a small base station and uplink synchronization between the MS and the small base station is completed, Wherein the RRC connection reconfiguration completion message transmitted to the small base station is transmitted to the macro base station.



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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190039225A (en) * 2016-08-11 2019-04-10 후아웨이 테크놀러지 컴퍼니 리미티드 Communication method and apparatus

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190039225A (en) * 2016-08-11 2019-04-10 후아웨이 테크놀러지 컴퍼니 리미티드 Communication method and apparatus
US11343725B2 (en) 2016-08-11 2022-05-24 Huawei Technologies Co., Ltd. Communication method and apparatus

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