KR20120074240A - Method for relaying of base station - Google Patents

Abstract

PURPOSE: A relay method of a BS(Base Station) is provided to enable the BS to be a relay station by establishing a relay link with adjacent base stations if the backhaul link is damaged. CONSTITUTION: In case a backhaul link is damaged, a multimode BS transmits AAI-MMADV(Advanced Air Interface Multimode Advertisement) message for a multimode function to a terminal(S110,S120). The multimode BS transmits an RNG-REQ(Ranging Request message) to a target BS(S130). The target BS negotiates basic performance with the multimode BS(S150). The multimode BS and the target BS constitutes ASN(Application System Network)(S180).

Description

Relay method of base station {METHOD FOR RELAYING OF BASE STATION}

The present invention relates to a relay method of a base station.

In the event of a disaster or disaster, important infrastructure can be destroyed or damaged. Many infrastructures, such as wireless telephones, landline telephones, and Internet networks, are considered important infrastructure infrastructures. If these communication facilities are destroyed or damaged, social congestion and disaster recovery can be difficult to secure. have. It is therefore important to have a means of quickly restoring or replacing telecommunications facilities.

On the other hand, the relay station serves to secure cell coverage by installing in a shaded area where the signal from the base station does not reach. If such a relay station is damaged during a disaster or disaster, providing means to replace the role of the relay station is an important component of communication recovery.

The problem to be solved by the present invention is that when the backhaul link of the base station is damaged in the communication system, the base station can establish a relay link with the adjacent base station to act as a relay station to perform a smooth communication task with the lower terminals Is to provide a way.

A method for relaying a base station according to the present invention is a method in which a first base station acts as a relay station to communicate with a second base station connected with a backhaul, the first base station forming a relay link with the second base station, and Starting the relay mode by the first base station.

The first base station may operate in a time-division transmit / receive (TTR) mode or a simultaneous transmit / receive (STR) mode.

The simultaneous transmission and reception mode may maintain a base station function.

The first base station may further include informing a lower terminal of performing a handover.

The first base station may include reconstructing a physical frame.

According to another embodiment of the present invention, a method for relaying a base station is a method in which a multi-mode base station operates as a relay station. transmitting an interface multimode advertisement (AAI-MM-ADV) message, the multi-mode base station performing ranging by an initial access method to request a relay link from a neighbor base station to which a backhaul is connected; Negotiating basic performance with the neighbor base station, exchanging authorization, authentication, and key with the neighbor base station by the multi-mode base station, and configuring operating parameters. .

The multi-mode base station may further include performing a registration procedure with the neighboring base station, and transmitting and receiving a message for requesting and accepting the relay link with the multi-mode base station.

The self-configuring broadcast message may include information for updating a parameter of a physical (PHY) or media access control (MAC) layer.

The self-configuring broadcast message may include an expected time required until the relay link establishment.

The at least one lower terminal may determine whether to stay in the multi-mode base station or handover to the neighbor base station based on the estimated time.

The multi-mode base station may maintain connection configuration information of the at least one lower terminal during the expected time.

The relaying method according to another embodiment of the present invention is a relaying method of a multi-mode base station. When the communication for establishing a relay link with a neighboring base station not connected to the multi-mode base station that is not backhauled is not possible, the multi-mode base station may be used. The base station transmits a delivery request message for requesting data delivery to the terminal, and receiving a delivery confirmation message from the terminal.

According to the present invention, when a backhaul link of a base station is damaged in a communication system, the base station sets up a relay link with a neighboring base station to serve as a relay station, thereby enabling smooth communication with the lower terminals.

1 is a flowchart illustrating an example of signaling for mode change in a relay method of a base station according to an embodiment of the present invention.
2 is a flowchart illustrating another example of signaling for mode change in a relaying method of a base station according to another embodiment of the present invention.
3 is a flowchart illustrating an example of a signaling procedure performed by a base station to a terminal in a method of relaying a base station according to an embodiment of the present invention.
4 is a flowchart illustrating another example of a signaling procedure performed by a base station to a terminal in a method of relaying a base station according to an embodiment of the present invention.
5 is a flowchart illustrating another example of a signaling procedure performed by a base station to a terminal in a method of relaying a base station according to an embodiment of the present invention.
6 is a flowchart illustrating signaling for mode change in a relaying method of a base station according to another embodiment of the present invention.
7 is an example of a flowchart illustrating handover occurring in a relaying method of a base station according to an embodiment of the present invention.
8 is another example of a flowchart illustrating handover occurring in a relaying method of a base station according to an embodiment of the present invention.
9 illustrates a callback handover according to another embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement 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 the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, a mobile station (MS) is a terminal, a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), an access terminal (access) It may refer to a terminal (AT), a user equipment (UE), or the like, and may include all or some functions of the terminal, MT, SS, PSS, AT, UE, and the like.

In addition, the base station (BS) is a node B (eB), an evolved node B (eNodeB), an access point (AP), a radio access station (radio access station (RAS)), a base transceiver station may refer to a base transceiver station (BTS), a mobile multihop relay (MMR) -BS, or the like, and may include all or a part of functions of a NodeB, an eNodeB, an AP, a RAS, a BTS, an MMR-BS, and the like.

According to an embodiment of the present invention, the base station may operate as a relay station to communicate with other base stations connected to the backhaul, and the base station may be referred to as a multi-mode base station. When the multi-mode base station operates in the relay mode, three operation methods are possible.

First, it is a time-division transmit and receive (TTR) mode. In the time division transmission / reception mode, a new secondary advanced preamble (SA-preamble) is used, and channel remutation is changed to perform cell reconfiguration. That is, handover with the lower terminal is required due to the RS configuration.

Next is Simultaneous Transmit & Receive (STR). Simultaneous transmission and reception mode maintains the function of the base station, and can use the existing preamble and channel permutation that were used when operating in the base station mode, and the base station for the simultaneous transmission and reception relay mode, although the handover procedure with the lower terminal is unnecessary. Ability is required.

Next is a mixed mode, which operates in a time division transmission / reception mode, but maintains a base station configuration in an access zone. That is, the handover with the lower terminal is unnecessary by using the preamble used in the normal base station operation and changing only the channel conversion in the relay zone while maintaining the channel conversion without change in the access area.

Now, the relaying method of the base station will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating an example of signaling for mode change in a relay method of a base station according to an embodiment of the present invention.

1 illustrates a general relay mode change procedure of a multimode base station (110).

Referring to FIG. 1, when a backhaul link is broken (S110), the multi-mode base station 110 transmits a self-configured broadcast message for advanced multi-mode function to the terminal 200. MM-ADV) is transmitted (S120). The self-organizing broadcast message (AAI-MM-ADV) may inform the terminal 200 of the service unavailable time due to a failure of the backhaul link. At this time, the terminal 200 capable of handover among the emergency terminals 200 may wait until the base station 110 attempts handover or restarts the service by setting up a relay link. In addition, while the multi-mode base station 110 performs communication with neighboring base stations to establish a relay link, the base station operating in the time division transmission and reception mode simultaneously broadcasts downlink synchronization signals and broadcasts for the lower terminal in the same subframe. Since it is difficult to transmit the information, the terminal 200 may notify the listening section through the self-configured broadcast message (AAI-MM-ADV) to inform the base station 110 when the base station 110 transmits the synchronization signal and the broadcast message. have.

Then, the multi-mode base station 110 transmits a ranging request message (RNG-REQ) to the target BS 120 (S130), and the target base station 120 ranges to the multi-mode base station 110. The response message (RNG-RSP) is transmitted (S140). The target base station 120 is a base station that will provide a relay link to replace the backhaul link of the multi-mode base station to the serving base station of the multi-mode base station. The ranging request message (RNG-REQ) and the ranging response message (RNG-RSP) may include a base station information and a mode change indication.

Subsequently, the multi-mode base station 110 and the target base station 120 negotiate basic performance (S150).

The multi-mode base station 110 and the target base station 120 exchanges authentication and encryption (S160), and the multi-mode base station 110 and the target base station 120 performs registration (S170). ). At this time, the authentication and registration procedure may be simplified or omitted depending on the function. Thereafter, the multi-mode base station 110 and the target base station 120 form an application system network (ASN) configuration (S180).

Subsequently, the multi-mode base station 110 and the target base station 120 transmit and receive relay station operating parameters (S190).

2 is a flowchart illustrating another example of signaling for mode change in a relaying method of a base station according to another embodiment of the present invention.

2 is a case where a multi-mode base station is a pre-configured BS.

Referring to FIG. 2, the multi-mode base station 110 negotiates basic performance with the target base station 120 (S210). Thereafter, the multi-mode base station 110 and the target base station 120 perform an authentication procedure (S220) and perform a pre-registration procedure (S230). Thereafter, the multi-mode base station 110 and the target base station 120 form an application system network configuration in advance (S240). This process is accomplished through backhaul communication.

At this time, the backhaul link may be broken (S250).

Then, the multi-mode base station 110 transmits a self-organizing broadcast message (AAI-MM-ADV) to the terminal 200 (S260). Then, the multi-mode base station 110 performs the ranging procedure by transmitting a ranging request message (RNG-REQ) to the target base station 120 (S270). In this case, the ranging request message (RNG-REQ) includes mode change information.

Then, the target base station 120 transmits a ranging response message (RNG-REP) to the multi-mode base station 110 (S280). In this case, the ranging response message (RNG-REP) may include relay station operating parameter information. The procedure may use not only ranging request / response messages but also other messages that function to request / accept relay links (including relay station operating parameter information).

3 is a flowchart illustrating an example of a signaling procedure performed by a base station to a terminal in a method of relaying a base station according to an embodiment of the present invention.

3 illustrates a case in which a physical layer PHY of an access zone is not changed.

Referring to FIG. 3, when the destruction of the backhaul link occurs (S310), the multi-mode base station 110 transmits a first self-configuration broadcast message (AAI-MM-ADV) to the terminal 200 (S320). Subsequently, the multi-mode base station 110 initiates a relay link establishment and service with the target base station 120 (S330). The multi-mode base station 110 transmits a second self-configuration broadcast message (AAI-MM-ADV) to the terminal 200 (S340). At this time, the second self-configuring broadcast message (AAI-MM-ADV) informs the start of the service through the relay link, and informs the capacity, quality and cell load information of the relay link. By using this, terminals capable of handover to another cell may use the corresponding information for handover triggering.

4 is a flowchart illustrating another example of a signaling procedure performed by a base station to a terminal in a method of relaying a base station according to an embodiment of the present invention.

4 illustrates a case in which a physical layer PHY of an access zone is changed.

Referring to FIG. 4, when the destruction of the backhaul link occurs (S410), the multi-mode base station 110 transmits a first self-configured broadcast message (AAI-MM-ADV) to the terminal 200 (S420). Subsequently, the multi-mode base station 110 initiates a relay link establishment and service with the target base station 120 (S430). The multi-mode base station 110 transmits a third self-configured broadcast message (AAI-MM-ADV) to the terminal 200 (S440). At this time, the third self-configured broadcast message (AAI-MM-ADV) is the physical frame information to be changed (for example, cell configuration and reconfiguration (cell configuration), such as index and relay mode information of the SA-preamble and Contains application start frame information. In addition, the third self-configured broadcast message (AAI-MM-ADV) informs the relay link capacity, the quality and the intra-cell load information, and a group handover command when handover is required. Here, the group handover command is an information field indicating a broadcast or multicast handover request and is information for performing handover without a separate handover ranging procedure.

The physical frame is then changed and service started. Thereafter, the multi-mode base station 110 performs ranging to the terminal 200 periodically (S450).

5 is a flowchart illustrating another example of a signaling procedure performed by a base station to a terminal in a method of relaying a base station according to an embodiment of the present invention.

5 illustrates a case in which the multi-mode base station 110 operates as a relay station.

Referring to FIG. 5, when the destruction of the backhaul link occurs (S510), the multi-mode base station 110 transmits a first self-organizing broadcast message (AAI-MM-ADV) to the terminal 200. After the multi-mode base station 110 starts the relay link establishment and service with the target base station 120 (S530), the multi-mode base station 110 sends a fourth self-configuring broadcast message (AAI-MM-ADV) to the terminal 200. ) Is transmitted (S540). In this case, the fourth self-organizing broadcast message (AAI-MM-ADV) includes physical layer frame information and application start frame information operating as a relay station, and includes relay link capacity, quality, and intra-cell load information.

Then, the physical layer frame is changed and the multi-mode base station 110 is switched to the relay station (S550). Then, the terminal 200 performs a handover procedure with the multi-mode base station 110 (S560), and the multi-mode base station 110 starts a service (S570).

6 is a flowchart illustrating signaling for mode change in a relaying method of a base station according to another embodiment of the present invention.

Referring to FIG. 6, when the multi-mode base station 110 breaks the backhaul link (S611), when the direct communication link for setting the relay link signal with the target base station 120 is not possible, that is, the multi-mode If a wireless communication link between the base station 110 and the target base station 120 is not possible, the terminal 200 may request data transmission. A forwarding request message (Forwarding REQ) may be transmitted for the data forwarding request (S612). Here, the forwarding REQ is a message for requesting the terminal to deliver the corresponding message to the neighboring base station at a specific time, and includes data that the base station wants to transmit to the neighboring base station. The forwarding REQ is a base station message to be transmitted to a neighboring base station and a time point at which a terminal scans with a neighboring base station, for example, a ranging request message (RNG-REQ), a base station ID (BS ID), and a base station state. Information, relay mode request information, and the like. The base station may selectively terminate the power or not use a specific frame region at the time of scanning of the terminal.

Then, the terminal 200 scans the target base station 120 (S614), and transmits a forwarding response message (Forwarding RSP) to the multi-mode base station 110 (S615). At this time, the forwarding response message (Forwarding RSP) is the terminal receiving the forwarding request message (Rewarding REQ) to inform the result of scanning the neighboring base station, if it is determined that the delivery is possible to transmit a payload portion (payload) to the base station to be.

Subsequently, the terminal 200 and the target base station 120 perform a Cdma code ranging procedure by transmitting and receiving a ranging confirmation message (RNG-ACK) (S616). The terminal 200 notifies that the ranging purpose is for delivery only, and transmits a ranging request message (RNG-REQ) including the base station ID, the base station status, and the relay request to the target base station 120 (S617). Then, the target base station 120 transmits a ranging response message (RNG-RSP) to the terminal 200 (S618).

Subsequently, the terminal 200 transmits a forwarding acknowledgment message (Forwarding ACK) to the multi-mode base station 110 (S619). The forwarding acknowledgment message (forwarding ACK) is a message that the terminal has completed the transfer to inform the base station, and if there is a response message received from the neighboring base station and forwards it, and includes a payload including the PDU of the ranging response message.

Then, the multi-mode base station 110 and the target base station 120 establishes a relay link (S620). In this case, the target base station 120 may use a directional antenna or increase transmission power for establishing a direct relay link with the multi-mode base station 110. In addition, a separate relay station may be operated near the multi-mode base station 110 to provide a multi-hop relay link. If the transmitting terminal is a multi-function terminal, the target base station 120 may request to operate the terminal in the relay mode.

On the other hand, when it is difficult to form a direct link between the multi-mode base station 110 and the target base station 120, when the multi-mode base station 110 operates only as a relay station or is not a pre-configured base station, as shown in FIG. The same message is transmitted and received with a separate relay station (not shown) instead of the target base station 120. Description of the detailed message is the same as that of FIG.

Meanwhile, in all the embodiments described above, handover during mode change may occur. When the service disconnection time is long during service operation, when there is capacity limitation of the relay link, when the capacity of the cell is limited due to factors such as transmission power, frame structure and resource allocation, and when the base station is changed to the relay station Handover may be performed. At this time, there are general handover, group handover, and callback handover.

A handover procedure will now be described in detail with reference to FIGS. 7 and 8.

7 is an example of a flowchart illustrating handover occurring in a relaying method of a base station according to an embodiment of the present invention.

Referring to FIG. 7, when a backhaul link is destroyed (S710), the multimode BS 110 serving as the serving BS of the terminal 200 relays with the target base station 120 for relaying. A link is set (S720). Thereafter, the multi-mode base station 110 transmits a handover command message (HO-CMD) to the terminal 200 (S730). In this case, the handover command message HO-CMD may be a group handover command message HO-CMD. The handover command message (HO-CMD) may include a cell information of the relay station and a handover time point, etc., to command a handover, and a handover command message (HO-CMD) may be broadcast for group handover of lower terminals. have.

Subsequently, the multi-mode base station 110 changes the physical layer frame and switches to the relay station to start the relay operation (S740). Then, the terminal 200 transmits the cdma ranging code to the multi-mode base station 110 (S750). In this case, the cdma ranging code may be a dedicated cdma ranging code.

Then, the multi-mode base station 110 transmits a ranging confirmation message (RNG-ACK) to the terminal 200 (S760). Here, the cdma ranging code and the ranging confirmation message (RNG-ACK) may determine a time point for handover according to the rank of the UE, and at this time, a dedicated cdma ranging code may be allocated.

 The terminal 200 transmits a ranging request message (RNG-REQ) to the multi-mode base station 110 (S770). Subsequently, the multi-mode base station 110 transmits a ranging response message (RNG-RSP) to the terminal 200 (S780).

8 is another example of a flowchart illustrating handover occurring in a relaying method of a base station according to an embodiment of the present invention.

Referring to FIG. 8, when the backhaul link is destroyed (S810), the multi-mode base station 110 transmits a self-organizing broadcast message (AAI-MM-ADV) to the terminal 200 (S811). The self-organizing broadcast message (AAI-MM-ADV) broadcasts an estimated service disconnection time due to a failure of the backhaul link.

Then, the terminal 200 transmits a handover request message (HO-REQ) including an expected time to the multi-mode base station 110 (S812), and the multi-mode base station 110 the expected time (expecte time). A handover command message (HO-CMD) including a) is transmitted to the terminal 200 (S813). In this case, the expected time is an estimated time required until the relay link is established. The estimated time may be used to estimate the service disconnection time of the lower terminals 200 of the multi-mode base station 110 that is not backhauled, and may refer to a time of starting a service using a relay link after the estimated time. have. The lower terminal 200 may determine whether to hand over to another base station 130 or stay in the current serving base station 110 with reference to this estimated time. The base station 110, which is not connected to the backhaul, may maintain connection configuration information of the lower terminals 200 for an expected time. At this time, the multi-mode base station 110 maintains and manages the connection information of the terminal for the expected time. On the other hand, by adding a callback handover enable field to the self-organizing broadcast message (AAI-MM-ADV), if a callback handover is possible, a handover request message (HO-REQ) or a handover command message ( The possibility of skipping the transmission / reception procedure of the HO-CMD) may be notified.

Then, the terminal 200 transmits a ranging request message (RNG-REQ) to a neighbor BS 130, that is, a target BS for MS for the terminal 200 (S814). The ranging request message (RNG-REQ) indicates a ranging purpose indication, i.e., a handover entry due to the destruction of the backhaul link, and adjacent to the estimated estimated time and the ID of the previous serving base station, that is, the multi-mode base station 110. Notifies the base station 130.

Subsequently, the adjacent base station 130 transmits a ranging response message (RNG-RSP) to the terminal 200 (S815). Then, the neighboring base station 130 and the terminal 200 performs communication (S816).

Thereafter, a relay link is established between the multi-mode base station 110 and the relay base station (BS for relaying) 140 (S817).

Then, the terminal 200 transmits a handover request message (HO-REQ) to the neighboring base station 130 (S818), and the neighboring base station 130 sends a handover command message (HO-CMD) to the terminal 200. To transmit (S819).

Then, the terminal 200 transmits a ranging request message (RNG-REQ) to the multi-mode base station 110 (S820), and the multi-mode base station 110 sends a ranging response message (RNG-RSP) to the terminal 200. It transmits (S821). Subsequently, the terminal 200 and the multi-mode base station perform communication (S822).

A callback handover will now be described in detail with reference to FIG. 9.

9 illustrates a callback handover according to another embodiment of the present invention.

Referring to FIG. 9, the base station 110 transmits a self-configuration broadcast message (AAI-MM-ADV) to the terminal 200 (S910). The self-organizing broadcast message (AAI-MM-ADV) informs of the unserviceable time due to the disconnection of the backhaul link, and informs the estimated time. During the expected time, the base station 110 maintains connection information of all terminals.

The terminal 200 performs a handover to the neighbor base station 130 (S920). Before the base station 110 reconfigures, handover with the neighboring base station 130 is possible, and the terminal 200 having high priority performs handover with the neighboring base station 130. The terminal 200 informs the neighboring base station 130 of the information of the serving base station 110 and the estimated time information through the handover.

The base station 110 changes the mode and establishes a relay link with the base station 140 (S930). That is, the base station 110 changes its function to the relay mode and performs a network entry process with the base station 140 to establish a relay link.

Subsequently, the base station 140 notifies the other base station 150 of the backbone message (S940). This is a message informing the other base station 150 of the reconfiguration and restart information of the base station 110.

Then, the base station 110 broadcasts reconfiguration and restart information to the lower terminals 210 (S950). This process is optional.

The base station 110 then changes the parameters of the physical layer.

Subsequently, the base station 110 performs a callback handover (S960). That is, the corresponding service is started by the ranging process.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (12)

A method for operating a relay station to communicate with a second base station, the first base station is connected to the backhaul,
The first base station forming a relay link with the second base station, and
Starting the relay mode by the first base station
Relay method comprising a. In claim 1,
The first base station operates in a time-division transmit and receive (TTR) mode or a simultaneous transmit and receive mode (Simultaneous Transmit & Receive, STR). In claim 2,
The simultaneous transmission and reception mode is a relay method for maintaining a base station function. In claim 1,
Notifying the lower terminal by the first base station of performing a handover
Relay method further comprising. In claim 1,
The first base station reconstructing a physical frame
Relay method comprising a. A method in which a multi-mode base station operates as a relay station,
Transmitting, by the multi-mode base station with no backhaul connection, an advanced air interface multimode advertisement (AAI-MM-ADV) message to at least one lower terminal;
Performing ranging by an initial access method for requesting a relay link from a neighboring base station to which a multi-mode base station has a backhaul connection;
Negotiating basic performance with the neighboring base station by the multi-mode base station;
The multi-mode base station exchanging authorization, authentication, and key with the neighbor base station, and
Steps to Configure Operating Parameters
Relay method comprising a. The method of claim 6,
The multi-mode base station performing a registration procedure with the neighbor base station, and
Transmitting and receiving a message for requesting and accepting the relay link with the multi-mode base station;
Relay method further comprising. The method of claim 6,
The self-organizing broadcast message includes information for updating a parameter of a physical (PHY) or media access control (MAC) layer. The method of claim 6,
The self-organizing broadcast message includes an expected time required until the relay link establishment. In claim 9,
The at least one lower terminal determines whether to stay in the multi-mode base station or handover to the neighbor base station based on the estimated time. In claim 9,
The multi-mode base station relays the connection configuration information of the at least one lower terminal for the expected time. As a relay method of a multi-mode base station,
Transmitting, by the multi-mode base station, a transmission request message for requesting data transmission to a terminal when communication for establishing a relay link with a neighboring base station not connected to the backhaul is not possible;
Receiving a delivery confirmation message from the terminal
Relay method comprising a.

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