KR20120012853A - Method of handover or mobile connection system for multicast broadcast service in mobile wireless communication system - Google Patents

Abstract

PURPOSE: A handover method of an MBS(Multicast Broadcast Service) in a mobile wireless communication system and a wireless connection system are provided to minimize map scheduling time during handover when a terminal moves from an MBS zone to another zone. CONSTITUTION: A serving ASN(Access Service Network) receives a handover request message including the IDs of a target RAS(Radio Access Station) and an MBS zone from a terminal. The serving ASN transmits an MBS MAP information request message including the IDs of the target RAS and the MBS zone to an MBS zone manager(S705). The serving ASN receives an MBS map information response message including a new MBS MAP that the target RAS will receive from the MBS zone manager(S708). A handover response message including the new MBS MAP is transmitted to the terminal(S709).

Description

Handover method and wireless access system of multicast broadcast service in mobile wireless communication system {METHOD OF HANDOVER OR MOBILE CONNECTION SYSTEM FOR MULTICAST BROADCAST SERVICE IN MOBILE WIRELESS COMMUNICATION SYSTEM}

The present invention relates to providing a multicast broadcast service in a mobile wireless communication system, and more particularly, to a method and system for performing handover.

3rd Generation Partnership Project (3GPP) long term evolution (LTE) and Institute of Electrical and Electronics Engineers (IEEE) 802.16m are being developed as candidates for the next generation wireless communication system. The 802.16m specification implies two aspects: past continuity, a modification to the existing 802.16e specification, and future continuity, a specification for the next generation of IMT-Advanced systems. Accordingly, the 802.16m standard requires all the advanced requirements for the IMT-Advanced system to be maintained while maintaining compatibility with the Mobile WiMAX system based on the 802.16e standard.

Wireless communication systems generally use one bandwidth for data transmission. For example, the second generation wireless communication system uses a bandwidth of 200KHz ~ 1.25MHz, the third generation wireless communication system uses a bandwidth of 5MHz ~ 10MHz. In order to support increasing transmission capacity, recent 3GPP LTE or 802.16m continues to expand its bandwidth to 20 MHz or more. In order to increase the transmission capacity, it is necessary to increase the bandwidth. However, even when the level of service required is low, supporting a large bandwidth can cause a large power consumption.

The IEEE 802.16m system supports the Evolved Multicast Broadcast Service (E-MBS). E-MBS is a point-to-multipoint system in which data packets are simultaneously transmitted from one source to multiple destinations. Broadcast means the ability to deliver content to all users. Multicast refers to content directed to a specific group of users subscribed to receive a specific service. Static multicast and dynamic multicast may be supported.

After receiving the packet, the terminal receives a desired burst of data using MBS MAP information. Map information is generated in the network, and serves to indicate the physical location of the data burst in the packet of the service requested by the terminal. Due to the characteristics of the multicast broadcast service, a service is continuously provided regardless of the presence or absence of a terminal in a certain region or a mode of the terminal.

Macro diversity is said to provide the same service in other RAS using existing map information without additional handover operation procedure between two Radio Access Stations (WiMAX) in World Interoperability for Microwave Access (WiMAX). In order to guarantee macro diversity, an access control router (ACR) managing a plurality of RASs manages an MBS zone and transmits the same map information to the RAS in the MBS zone. As such, even if the UE accesses any RAS using one map information, the UE may receive a burst at the same location without a handover process.

However, when leaving the MBS zone, the RAS of the other zone may not include the burst at the same position, and the update of the MBS MAP is necessary. The terminal may need a handover process between the serving ASN and the target ASN, and may need to update map information for the MBS in the ACR managing the RAS to be handed over. In order to continuously receive the MBS service, a quick update of the map information is required, and a method of minimizing the process of receiving the map information by the terminal during the handover process is required for the quick update.

The technical problem of the present invention is to support the fast handover by minimizing the map scheduling time when the UE moves from one MBS zone to another zone.

A method of performing a handover from a serving ASN (Access Service Network) to a target ASN including a target Radio Access Station (RAS) in a multicast broadcast service (MBS) is performed by the serving ASN from the terminal to the target. Receiving a handover request message including a RAS and an MBS zone ID, transmitting an MBS MAP information request message including the target RAS and the MBS zone ID to an MBS zone manager, and the target RAS from the MBS zone manager Receiving an MBS map information response message including a new MBS MAP to be received by the UE; and transmitting a handover response message including the new MBS MAP to a terminal, wherein the MBS zone manager is a MBS MAP of a neighbor ASN. A MBS zone table for receiving MBS MAP information for each MBS zone based on the MBS MAP of the neighboring ASN, and generating the MBS zone table. From to generate the new MBS MAP to be received by the target RAS.

When the UE moves to another MBS zone, handover can be performed more quickly. Specifically, fast handover can be performed by reducing network cost and reducing the number of messages.

1 illustrates a network structure for providing a multicast broadcast service in a mobile WiMAX environment.
2 is a diagram illustrating a network system that provides an MBS service in a mobile WiMAX environment.
3 shows an example of a frame structure.
4 shows a method of transmitting MBS data.
FIG. 5 relates to a wireless access system for performing fast handover between MBS zones using an MBS zone manager in accordance with the present invention.
6 is a flowchart illustrating a handover to continuously provide an MBS service when a UE moves to another MBS zone in a mobile WiMAX environment.
7 is a flowchart for performing handover quickly by using an MBS zone table according to the present invention.

Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In addition, in describing the component of this specification, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms.

1 illustrates a network structure for providing a multicast broadcast service in a mobile WiMAX environment.

According to FIG. 1, a CSN (Connectivity Service Network) manages a server and a policy for managing an MBS. The ASN (Access Service Network) manages the MBS, and the ASN includes an Access Connection Router (ACR) and a Radio Access Station (RAS).

The ACR manages the MBS Zone through the MBS Proxy. Pass content packets between distributed data path functions and RAS's MBS data path functions. During packet delivery, the MBS synchronization manager delivers map information indicating burst information to be received by the UE to the RAS. The upper sync runner and the lower sync runner transmit the last packet frame received by the terminal to the RAS through the air interface. Since the map information delivered by the MBS Synchronization Manager is all delivered to the RAS included in the same MBS zone, the burst location for the MBS is the same when generating packets through the synchronous performer in each RAS.

2 is a diagram illustrating a network system that provides an MBS service in a mobile WiMAX environment.

According to FIG. 2, in the same MBS zone, macro diversity can be guaranteed by sharing map information between ACR and RAS by a synchronization manager, but if the MBS zones are not the same, handover between ACRs must be performed and a map delivered by the synchronization manager is provided. Difficult to share information In order to provide an MBS service, after handover, a map scheduling for generating an MBS burst is required again, and a delay time may occur accordingly.

3 shows an example of a frame structure. The hierarchical cell structure may be a frame structure of at least one of a macro cell and a femtocell.

Referring to FIG. 3, a frame refers to a data sequence for a fixed time used by a physical specification. A superframe includes a superframe header (SFH) and four frames F0 and F1. , F2, F3). The first subframe of each superframe includes a primary superframe header (P-SFH) and may periodically include a secondary superframe header (S-SFH). The size of each superframe is 20ms and the size of each frame is illustrated as 5ms, but is not limited thereto. The superframe header may be disposed at the earliest in the superframe, and a common control channel is assigned to the superframe header. The common control channel is a channel used for transmitting control information that can be commonly used by all terminals in a cell, such as information on frames or system information of a superframe. A synchronization channel for transmitting a synchronization signal may be arranged in the superframe header or adjacent to the superframe header. The synchronization signal may indicate cell information such as a cell ID.

One frame includes a plurality of subframes (Subframe, SF0, SF1, SF2, SF3, SF4, SF5, SF6, SF7). Each subframe may be used for uplink or downlink transmission. A time division duplexing (TDD) scheme or a frequency division duplexing (FDD) scheme may be applied to the frame. In the TDD scheme, each subframe is used for uplink transmission or downlink transmission at different times at the same frequency. That is, the subframes in the frame of the TDD scheme are classified into an uplink subframe and a downlink subframe in the time domain. In the FDD scheme, each subframe is used for uplink transmission or downlink transmission at different frequencies at the same time. That is, subframes in the frame of the FDD scheme are divided into an uplink subframe and a downlink subframe in the frequency domain. Uplink transmission and downlink transmission occupy different frequency bands and may be simultaneously performed. Each subframe may include a subframe header. The subframe header may include radio resource allocation information of the subframe.

4 shows a method of transmitting MBS data.

Referring to FIG. 4, in a scheme of separately transmitting unicast data and MBS data in a time division multiplexing (TDM) scheme, a specific subframe is transmitted for MBS data transmission (ie, MBS region). Assign. The transmission format and size of MBS data is informed through a message called MBS MAP, and an MBS MAP message defines access of uplink / downlink information in a subframe. The MBS MAP may be included in every subframe in which MBS data is carried or may be periodically included. The location of the MBS MAP is informed by the secondary superframe header, and the location of the next MBS MAP is informed by the MBS MAP. Accordingly, the UEs that start the MBS service receive the MBS data by identifying the location of the first MBS MAP from the auxiliary superframe header, and then operate in a manner of receiving the MBS MAP and searching for the next MBS MAP without the assistance of the auxiliary superframe header. can do.

The terminal receives the MBS configuration message for the MBS service. The MBS configuration message may include information of the MBS MAP that defines the transmission characteristics of the MBS data burst. The MBS setup message includes information such as the number of MBS zones, MBS zone ID, MBS Scheduling Interval (MSI), MBS MAP Resource Index (MBS MAP Resource Index), MBS MAP Isizeoffset, and MBS MAP Multi Input Multi Ouput (MIMO) Mode. can do.

The MBS MAP included in the MBS configuration message defines the characteristics of the MBS data burst transmitted for the MBS service. The MBS AMP may include information such as the number of streams, a stream ID, an Isizeoffset, a MIMO mode for MBS data burst, a frame / subframe offset, a resource index, an allocation period, and the like.

It is possible to indicate the MBS MAP through the MBS configuration message, and the terminal can access the corresponding resource. By accessing the stream corresponding to the content of the MBS through the MBS MAP, it is possible to prevent unnecessary data decoding.

MBS MAP information is obtained through the MBS setting message, stream information corresponding to the content is obtained based on the received MBS MAP, and the corresponding MBS data burst is received and decoded. Such configuration information may be included in a specific control channel, MAC header, other configuration message, as well as MBS configuration message. However, hereinafter, it is described that it is included in the MBS configuration message and the MBS MAP, and the above description is only an example and is not limited only to the case included in the MBS configuration message and the MBS MAP.

In addition, this method can be applied to not only transmitting MBS data but also expressing an area such as a message / control channel for general data transmission and data transmission.

Hereinafter, the fast handover will be described through the MBS zone manager including the MBS zone table.

FIG. 5 relates to a wireless access system for performing fast handover between MBS zones using an MBS zone manager in accordance with the present invention.

According to FIG. 5, an MBS zone manager receives an MBS MAP of each neighboring ASN of a neighboring ASN, generates an MBS zone table based on information on the MBS zone and each of the MBS MAPs, and enables a UE to perform handover. In this case, the MBS zone table is used to schedule whether to transmit the MBS MAP of the target ASN at which point, at what period, or to which location. The MBS zone manager manages information on the MBS zone managed by the ASN in a table form, and updates and transmits MBS map information for supporting the MBS service when the MBS zone changes according to the movement of the terminal. By receiving the updated map information, the terminal can reduce the map scheduling time with the anchor ACR, thereby enabling fast handover. The MBS zone table may search, maintain or update each MBS MAP by distinguishing MBS services based on the target RAS and the MBS zone ID.

6 is a flowchart illustrating a handover in order to continuously provide an MBS service when a UE moves to another MBS zone in a mobile WiMAX environment.

According to FIG. 6, through the neighbor ASN information notification message, the terminal receives neighbor RAS and MBS zone ID information supported by each RAS (S601). It is determined whether or not the MBS zone supported by the neighboring RAS by checking and comparing the ID information of the MBS zone including each RAS (S602). If so, handover through macro diversity is performed (S603). If not, since the MBS zone supported by the neighboring RAS is not the same as the serving RAS and the MBS zone, handover is required, and the UE transmits a handover request message to the serving ASN (S604). Subsequently, the serving ASN transmits a handover response message to the terminal (S605). When the terminal transmits the handover performance message to the serving ASN (S606), the serving ASN performs the handover, and the terminal generates a data path of the target ASN including the RAS to be connected (S607). The data path is released from the other ASN (S608), and the data path is also released from the existing serving ASN (S609). After creating a new data path, the UE re-requests a service previously provided using the generated data path, and receives map scheduling and new synchronization information for generating a burst between the ACR and the RAS (S610). Through this process, handover and multicast broadcast service guarantee procedures are completed.

7 is a flowchart for performing handover quickly by using an MBS zone table according to the present invention.

According to FIG. 7, the UE receives adjacent RAS and MBS zone ID information supported by each RAS using the neighbor ASN information notification message (S701). By checking and comparing the ID information of the MBS zone including each RAS, it is determined whether the neighboring RAS supports the MBS zone (S702). If so, handover through macro diversity is performed (S703). If not, since the MBS zone supported by the neighboring RAS is not the same as the serving RAS and the MBS zone, handover is required, and the UE transmits a handover request message including the target RAS information and the serving MBS zone ID information (S704). . The serving ASN transmits an MBS map information request message including the target RAS information and serving MBS zone ID information to an MBS zone manager (S705).

The MBS zone manager performs a map scheduling process with the target ASN (S706) to generate a new MBS MAP to be used after the handover for the MBS (S707). The MBS MAP information response message including the new MBS MAP to be received by the new target RAS is transmitted to the serving ASN (S708). Here, the new MBS MAP is generated in the MBS zone manager, the MBS zone manager receives the MBS MAP of the neighbor ASN (S713), and MBS MAP information for distinguishing MBS MAP information for each MBS zone based on the MBS MAP of the neighbor ASN. A zone table is generated (S714), and a new MBS MAP to be received at the target RAS is generated from the MBS zone table (S707).

The serving ASN transmits to the handover response message terminal including the new MBS MAP (S709). Upon receiving the map information, the UE transmits a handover performance message to the serving ASN (S710), and the serving ASN transmits a handover confirmation message to the target ASN (S711), and then the target ASN and data including the new RAS. Create a path (S712). Such handover can obtain the burst location information for the MBS service quickly and simply by receiving the MBS MAP from the MBS zone table even if another MBS zone is different.

 Table 1 relates to the MBS zone table managed, maintained and updated by the MBS zone manager according to the present invention.

MBS Zone ID Request terminal ID Handover Path Information MBS Service Contents MBS MAP Information Renewal time X - X Broadcast A
Local broadcast B MBS_MAP_IE_X
MBS_DATA_IE_X
MBS_MAP_X HH: MM: SS Y - Y Broadcast C, D
Local broadcast A MBS_MAP_IE_Y
MBS_DATA_IE_Y
MBS_MAP_Y HH: MM: SS X MN_A X-> Y Broadcast A
Broadcast C, D
Local broadcast A MBS_MAP_IE_W
MBS_DATA_IE_W
MBS_MAP_W HH: MM: SS Y MN_C Y-> X Broadcast C, D
Broadcast A
Local broadcast B MBS_MAP_IE_Z
MBS_DATA_IE_Z
MBS_MAP_Z HH: MM: SS .
.
. .
.
. .
.
. .
.
. .
.
. .
.
.

According to Table 1, the MBS zone table may include MBS zone ID, request terminal ID of ASN, handover path, MBS service contents, MBS MAP information, and update time as components. Through the MBS zone table, the target RAS and MBS zone ID information provided by the UE may be used to search for information on MBS services including the MBS MAP previously provided. In addition, it is possible to confirm and maintain whether the RAS can support the MBS service, and can directly transfer the MBS MAP information to the terminal depending on whether the service is supported. When the MBS MAP based on the new MBS zone ID is transmitted, the MBS zone table may be updated and new MBS MAP information may be stored.

According to the MBS zone table, when the MBS zone ID is X, it can be seen that the broadcasting service is broadcast A and local broadcast B. At this time, the MBS MAP IE (MBS MAP Information Element), MBS DATA IE (MBS DATA Information Element) and MBS MAP information, etc. can be known, and the time at which the MBS information is updated can also be known. Similarly, when the MBS zone ID is Y, it can be seen that the service contents are broadcast C, D, and local broadcast A, and MBS MAP information and update time information can be known.

Next, in the case where the path is moved from the MBS zone having the MBS zone ID of X to the MBS zone of the Y, the broadcast A that is being serviced in the MBS zone having the MBS zone ID of X and the broadcast that should be serviced in the MBS zone having the MBS zone ID of Y MBS MAP information about C, D and local broadcast A can be known through MBS zone table information. At this time, the local broadcast B is broadcast only in the MBS zone where the MBS zone ID is X and does not need to be broadcast in the MBS zone where the MBS zone ID is Y.

When the path is moved from the MBS zone with the MBS zone ID of Y to X in the MBS zone, the broadcasts C, D and the broadcast A that need to be serviced in the MBS zone with the MBS zone ID of X in the MBS zone having the MBS zone ID of Y And MBS MAP information about local broadcast B can be known through MBS zone table information. At this time, the local broadcast B is broadcast only in the MBS zone where the MBS zone ID is Y and does not need to be broadcast in the MBS zone where the MBS zone ID is X.

In this way, it is possible to know what broadcasts are provided for each MBS zone or MBS MAP, without having to transmit information on the MBS zone table. Through the MBS Zone Manager, the MBS Zone Table can be managed and the MBS MAP can be generated to perform fast handover. In addition, by storing the path information of the terminal using the MBS zone table information, when the terminal returns to the existing MBS zone or when another terminal performs the same handover, it is possible to quickly transfer the map information using the path information.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (9)

A method for performing a handover from a multicast broadcast service (MBS) to a target ASN including a serving Radio Access Station (RAS) in a serving Access Service Network (ASN),
The serving ASN receiving a handover request message including the target RAS and MBS zone ID from a terminal;
Transmitting an MBS MAP information request message including the target RAS and the MBS zone ID to an MBS zone manager;
Receiving an MBS map information response message including a new MBS MAP to be received at the target RAS from the MBS zone manager;
Transmitting a handover response message including the new MBS MAP to a terminal;
The MBS zone manager receives the MBS MAP of the neighbor ASN,
Generate an MBS zone table for distinguishing MBS MAP information for each MBS zone based on the MBS MAP of the neighbor ASN,
And generating the new MBS MAP to be received at the target RAS from the MBS zone table. The method of claim 1,
The MBS zone table includes at least one of an MBS zone ID, a requesting terminal ID of an ASN, a handover path, service contents, MBS MAP information, and an update time. The method of claim 2,
And the MBS zone manager searches for, maintains or updates each MBS MAP by distinguishing an MBS service based on the target RAS and the MBS zone ID. The method of claim 2,
When the MBS MAP based on the new MBS zone ID is transmitted as the terminal moves, the MBS zone table is updated to include the MBS MAP. A method for performing a handover from a multicast broadcast service (MBS) to a target ASN including a target radio access station (RAS) in a serving access service network (ASN),
Transmitting, by the UE, a handover request message including the target RAS and MBS zone ID to the serving ASN;
Receiving a handover response message including a new MBS MAP to be received at the target RAS from a serving ASN; And
Performing handover based on the new MBS MAP;
The new MBS MAP is generated by scheduling with the target ASN from the MBS zone table of the MBS zone manager, handover method. In a wireless access system that provides a multicast broadcast service in the mobile Internet (WiMAX),
Receive MBS MAP of each neighbor ASN of neighbor ASN,
Generate an MBS zone table based on information on the MBS zone and each of the MBS MAPs,
And a MBS zone manager for scheduling at which point in time, at what period, or at which location the MBS MAP of a target ASN is to be transmitted using the MBS zone table when the terminal performs handover. The method according to claim 6,
The MBS zone table includes at least one of an MBS zone ID, a request terminal ID of an ASN, a handover path, service contents, MBS MAP information, and an update time. The method of claim 7, wherein
And the MBS zone table searches for, maintains or updates each MBS MAP by distinguishing an MBS service based on the target RAS and the MBS zone ID. The method of claim 7, wherein
And when the MBS MAP based on the new MBS zone ID is transmitted as the terminal moves, the MBS zone table is updated to include the MBS MAP.

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