KR20090062193A - Apparatus and method for obtainment and correction of time of date in broadband wireless access system - Google Patents

Abstract

An apparatus for enabling a terminal to obtain or correct absolute time and data information in a broadband wireless access system and a method thereof are provided to allow the terminal which has not a GPS receiver to perform a reserved broadcasting program recording service when the real broadcasting is started or is terminated without the separate interworking procedure between the terminal and a base station. The initial network entry procedure is performed(301). The initial absolute time and data information is obtained(303). A terminal manages absolute time and data information by using the obtained initial absolute time and data information and its local clock(305), and receives a frame number through a down link map periodically transmitted from the base station(307). The absolute time and data information is corrected(309).

Description

Apparatus and method for a terminal to acquire and correct absolute time information in a broadband wireless access system {APPARATUS AND METHOD FOR OBTAINMENT AND CORRECTION OF TIME OF DATE IN BROADBAND WIRELESS ACCESS SYSTEM}

The present invention relates to a broadband wireless access system, and more particularly, to an apparatus and a method for a terminal to obtain and correct absolute visual information.

In general, communication systems have been developed mainly for voice services, and are gradually developing into communication systems capable of not only voice but also data services and various multimedia services. However, the voice-oriented communication system has not satisfied the rapidly increasing user's service needs due to the relatively small transmission bandwidth and high usage fee. In addition, due to the development of the communication industry and increasing user demand for Internet services, there is an increasing need for a communication system capable of efficiently providing Internet services. As a result, it has been introduced into a broadband wireless access system for efficiently providing Internet services with broadband enough to meet the demand of rapidly increasing users.

The broadband wireless access system is a system for integrating and supporting not only voice but also various low speed and high speed data services and multimedia application services such as high definition video. The broadband wireless access system is based on a wireless medium using broadband such as 2GHz, 5GHz, 26GHz and 60GHz, in a mobile or fixed environment, public switched telephone network (PSTN), public switched data network (PSDN), internet network, IMT2000 network, It is a wireless communication system that can connect ATM (Asynchronous Transfer Mode) network and can support channel rates of 2Mbps or more. The broadband wireless access system may be classified into a broadband wireless subscriber network, a broadband mobile access network, and a high-speed wireless local area network (LAN) according to terminal mobility (fixed or mobile), communication environment (indoor or outdoor), and channel transmission rate. .

The wireless access method of the broadband wireless access system is being standardized by the International Organization for Standardization. The WiMAX system, one of the broadband wireless access systems, is an IEEE 802.16 standardization group of the Institute of Electrical and Electronics Engineers. Is being standardized on. Compared to the conventional wireless technology for the voice service, the IEEE 802.16 standard has a wider bandwidth of data and can transmit a lot of data in a short time, and all users can efficiently use the channel by sharing a channel (or resource). Do. In addition, quality of service (QoS) is guaranteed so that users can receive different quality services according to the characteristics of the service.

In the IEEE 802.16 system, a multicast and broadcast service capable of providing multicast and broadcast to a plurality of mobile terminals is referred to as a multicast and broadcast service (hereinafter referred to as 'MCBCS'), and according to the intention of a standardization group or an operator, 'MBS'. May be called). In the MCBCS standard, an MBS zone (MBS zone) refers to an area composed of one subcell or multiple subcells that transmit the same broadcast channel or content at the same frequency and at the same time. . Each subcell in the MBS zone uses the same connection identifier (hereinafter, referred to as "CID") for the same broadcast channel or content. Here, the subcell is a group consisting of one frequency and one sector. In general, a multicast connection identifier (hereinafter referred to as 'MCID') has a 1: 1 mapping relationship with one broadcast channel having a multicast IP, and a logical channel identifier (hereinafter referred to as 'LCID'). (I.e., " 1 ") is mapped to ID, i.e., content ID, for distinguishing various broadcast contents included in payload of the same multicast IP. The base station transmits the MBS zone ID list through a downlink channel descriptor (DDC) message to broadcast information on whether the base station is a base station capable of MCBCS service and which zone it belongs to. The MBS zone may consist of a single base station or of a plurality of base stations.

Unlike the existing unicast service, the MCBCS service is received by multiple base stations transmitting the same broadcast content at the same time in the same time unit in MBS zone, and receiving and combining packets received from multiple base stations by the receiving terminal. It can improve performance. In the case of the existing unicast service, when the terminal exists at the cell edge, data transmission and reception are not smooth due to large interference between cells. However, in the case of the MCBCS, even if the terminal is located at the cell boundary, neighboring base stations transmit the same content at the synchronized time, so that the same data can be received and used from various base stations. This effect is called macro diversity gain.

The required capacity for each flow of the MCBCS service varies from 32 Kbps, 64 Kbps, 128 Kbps, 256 Kbps, 384 Kbps, 500 Kbps, and 1 Mbps. 64 Kbps or less is mainly used when providing contents such as audio or text message through MCBCS service, and the capacity of normal video & audio service used in DMB (Digital Multimedia Broadcasting), etc. It is 384 Kbps and 128 Kbps is used to provide a low quality video service, and 1Mbps or more is used to provide a high quality video service. In general, in the case of the MCBCS service, it is common to vary the channel configuration and transmission rate for each MBS zone.

In order to receive the MCBCS service, the terminal manages a broadcast schedule, and a user may watch the broadcast at a desired time by watching or recording (stored in the terminal internal memory) at a corresponding time using the broadcast schedule. For this purpose, the terminal should acquire absolute time (for example, November 25, 2007, 18:32:19) information. If the terminal has a Global Positioning Satellite (GPS) receiver, the absolute time information can be easily obtained. However, if the terminal does not have a GPS receiver, there is a problem in that there is no method of acquiring the absolute time information according to the IEEE 802.16e standard.

Accordingly, an object of the present invention is to provide an apparatus and method for acquiring and correcting absolute visual information by a terminal in a broadband wireless access system.

Another object of the present invention is to obtain absolute time information through direct input by a user or interworking with an NTP server after performing an initial network entry procedure in a broadband wireless access system, and periodically receiving the DL MAP message from a base station. An apparatus and method are provided for correcting the absolute time information by using a frame number.

Another object of the present invention is to provide an apparatus and method for acquiring and correcting absolute time information using a broadcast message received from a base station, for example, a DCD message or an MCBCS MAP message, in a broadband wireless access system.

Another object of the present invention is to manage the absolute time information of the terminal in the broadband wireless access system, when the user has made a reservation for a specific broadcast content, the terminal performs the internal operation required for receiving the broadcast at the broadcast time to perform the broadcast An apparatus and method for receiving and storing or reproducing in real time.

According to an exemplary embodiment of the present invention, a method of correcting absolute time information of a terminal includes: obtaining initial absolute time information; receiving a frame number through a downlink map message; And correcting absolute time information by using initial absolute time information and the received frame number.

According to an exemplary embodiment of the present invention, a method of obtaining absolute time information of a terminal may include receiving a broadcast message including absolute time information from a base station, and receiving the absolute time information from the broadcast message. Characterized in that it comprises a process of extracting and storing.

In order to achieve the above object, according to an embodiment of the present disclosure, an apparatus for correcting absolute time information of a terminal may include: an initial absolute time information obtaining unit obtaining initial absolute time information, and a frame receiving a frame number through a downlink map message; And a number receiver, and an absolute time information corrector that corrects absolute time information by using the obtained initial absolute time information and the received frame number.

According to an embodiment of the present invention to achieve the above object, the apparatus for obtaining absolute time information of a terminal includes a receiver for receiving a broadcast message including absolute time information from a base station, and the absolute time information in the broadcast message. Characterized in that it comprises a storage unit for extracting and storing.

The present invention provides an apparatus and a method for a terminal to acquire and correct absolute time information in a broadband wireless access system, thereby starting a broadcast reservation recording service without a separate terminal-base station interworking procedure for a terminal without a GPS receiver. And there is an advantage that can be performed in accordance with the end time. Furthermore, the present invention activates the MCBCS service and is expected to play a large part in strengthening the competitiveness of mobile WiMAX in the future.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, an apparatus and method for acquiring and correcting absolute time information by a terminal in a broadband wireless access system according to the present invention will be described.

In the following description, the name of the network entity (NE: Network entity) is defined according to the corresponding function, and may vary according to the intention of the standardization group or the operator. For example, a base station may be referred to as a radio access station (RAS) or a base station (BS), and a base station controller may be an access control router (ACR) or an access service network-gateway (ASN-GW). Gateway). Here, the ASN-GW may perform a router function as well as a base station controller function.

Here, the subjects related to the MCBCS service will be described. Typically, subjects related to the MCBCS service are a content provider (hereinafter referred to as "CP"), a service provider (hereinafter referred to as "SP"), and a network operator (hereinafter referred to as "AP"). , User includes.

First, the CP is responsible for producing and supplying the content provided by the MCBCS service, the SP is supplied with the content from the CP, serves to serve the user for free or a fixed fee for the content, The AP is responsible for transmitting the service of the SP to users. The CP, SP, and AP may each be independent operators, but one operator may play all roles or two or more roles. An example thereof may be a terrestrial broadcasting operator in Korea.

1 is a diagram illustrating a network structure for providing an MCBCS service of a broadband wireless access system according to the present invention.

As shown, the network structure is a security server (150), MCBCS application server (hereinafter referred to as 'AS') (140-1, 140-2), MCBCS server 130, MCBCS The controller 120, the base station 110, and the terminal 100 are configured to be included. Here, the MCBCS controller 120 may be an independent device located with the base station controller, the base station controller may be configured to include the function of the MCBCS controller.

Referring to FIG. 1, first, the security server 150 belongs to an area of the SP and performs functions such as authentication, authorization, and billing processing for the user's subscription to the MCBCS service.

The MCBCS ASs 140-1 and 140-2 belong to the area of the SP and have a subscription processing / management function for the user who has subscribed to the MCBCS service, a function for transmitting the contents of the MCBCS service to the AP, and a fraudulent user. It performs user authentication for access control, protects content supplied to CP, manages terminals of multiple users, and provides information required for MCBCS services. In FIG. 1, the difference between MCBCS AS 1 140-1 and MCBCS AS 2 140-2 is that MCBCS AS 1 140-1 provides a free service or a user control function and a content protection function. It is an MCBCS AS for an SP that does not provide the MCBCS AS 2 (140-2) is a MCBCS AS for an SP that provides a paid service, fraudulent user control function and content protection function. Hereinafter, the functions of the MCBCS ASs 140-1 and 140-2 will be described in detail.

-MCBCS service information, for example, service guide generation: When creating a service guide, it follows the mutually agreed data model between MCBCS ASs.

-Perform subscription procedure to receive MCBCS service of user

-In conjunction with the security server 150, performs user authentication, permission to use, billing processing, etc.

-User group management by MCBCS channel or MCBCS content

-Management and distribution of authentication key by group

-Unauthorized user access control / multimedia content protection (Service Protection / Content Protection): Content encryption and decryption key management and distribution

-Stream Transmission / File Transmission: Definition of transmission protocol, management of reception report to check whether user has received MCBCS contents normally, file metadata (File transmission) for file transmission Metadata Management

-User Interaction: Provides interactive service with users

-Notification / Alert: Provides a service to notify users who have subscribed to MCBCS service when there is a change in broadcasting schedule or emergency broadcasting is required.

The MCBCS server 130 is an entity that plays a central role in the AP, and collects and transmits MCBCS service information (eg, a service guide) from various SPs, manages for efficient use of network resources, and manages data by a user terminal. It provides support function for error-free reception. Detailed functions are as follows.

-MCBCS Transmission Zone Management: Management of base stations in the area to be serviced by SP

-Service Guide processing: Aggregate service guides received from MCBCS AS, service guide compression to reduce fragmentation, network resource consumption, and maintenance management of service guides as needed.

-Service Guide Deployment: Unicast or Multicast Methods

-Stream Transmission / File Transmission: Check whether the user has received the MCBCS contents normally (sometimes play the same role as MCBCS AS)

-Multicast group management through user location tracking

-Receipt report processing: When the user reports the network status through the reception report, it is reflected.

The MCBCS controller 120 is located in the AP, and functions to efficiently transmit the MCBCS service transmitted through the central network as a connection part of the central network and the access network through the wireless network, and to inform the user terminal of the start of the MCBCS service. It supports the functions, and detailed functions are as follows.

Data / time synchronization to provide macro diversity gain: Burst reservation allocation and packet processing

-MBS zone management

-Group paging information delivery for notification

Here, the MCBCS controller 120 directly interfaces only with the MCBCS server 130, and interfaces with different SPs are possible only through the MCBCS server 130.

The base station 110 is responsible for the wireless transmission of the MCBCS service transmitted by wire, and is managed by the AP.

The terminal 100 serves as a user terminal to provide a user with the MCBCS service transmitted through the network entities.

Lastly, although not shown, the policy server manages QoS profile information for each IP flow for a terminal requesting a service.

Herein, a service area shown in FIG. 1 represents an area in which the SP provides a service, and the MCBCS transmission zone is a transmission management area defined by the AP for efficient transmission of MCBCS services in the service area. Indicates an area where the same content is broadcasted. On the other hand, the MBS zone refers to an area in which MCBCS service flows are valid through different connection identifiers (CIDs) or different security associations (SAs).

2 is a block diagram illustrating a configuration of an apparatus for obtaining and correcting absolute time information in a terminal of a broadband wireless access system according to an exemplary embodiment of the present invention.

As shown in the drawing, the initial absolute time information acquisition unit 201, the storage unit 203, the absolute time information correction unit 205, and the frame number receiving unit 207 are configured.

Referring to FIG. 2, the initial absolute time information acquisition unit 201 acquires initial time of date (ToD) information in association with an NTP server after performing an initial network entry procedure. The acquired absolute absolute time information and the corresponding initial frame number are stored in the storage unit 203. Alternatively, initial absolute time information may be obtained by receiving a standard time directly from the user.

The absolute time information correcting unit 205 uses the frame number provided from the frame number receiving unit 207, the initial absolute time information stored in the storage unit 203, and the corresponding initial frame number. Correct it. In other words, based on the initial absolute time information and the corresponding initial frame number, each time a subsequent frame number is received, a time corresponding to (difference between the received frame number and the initial frame number) × (frame period) Recognize that the elapsed time and correct the absolute time information.

The frame number receiver 207 receives a frame number (FN) through a DL MAP (DownLink MAP) periodically transmitted from a base station, and transmits the received frame number to the absolute time information corrector 205. to provide.

Lastly, although not shown, the terminal is generally a software block for managing absolute time information using the corrected absolute time information (initial absolute time information, if not corrected) and a local clock. It includes a local clock section and a client program, which is a software block that manages the broadcasting function of middle ware or application layer. If the user has made a reservation for a specific broadcast content, the client program of the terminal periodically checks the absolute time information managed by the local clock unit, and then performs an internal operation of the terminal necessary for receiving a broadcast at the corresponding broadcast time. Receive and store broadcasts or play them back in real time.

3 is a flowchart illustrating a procedure of a method for acquiring and correcting absolute time information in a terminal of a broadband wireless access system according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the terminal performs an initial network entry procedure in step 301, and then, in step 303, the terminal provides accurate initial absolute time (ToD) information within one frame in association with an NTP server. Acquire. In other words, the terminal obtains the absolute absolute time information by requesting transmission of absolute time information to the NTP server through the application layer and receiving it from the NTP server. Alternatively, initial absolute time information may be obtained by receiving a standard time directly from the user. In this case, the terminal stores the obtained initial absolute time information and the corresponding initial frame number. In step 305, the terminal manages absolute time information using the acquired initial absolute time information and a local internal clock of the terminal.

After that, the terminal receives a frame number (FN) through DL Link (AP MAP) periodically transmitted from the base station in step 307, the received frame number and the obtained initial absolute time in step 309 The absolute time information is corrected using the information. Since the frame number is transmitted exactly in units of an integer multiple of the frame, the terminal may correct absolute time information by using the frame number. That is, based on the initial absolute time information and the corresponding initial frame number, each time a subsequent frame number is received, a time corresponding to (difference between the received frame number and the initial frame number) × (frame period) elapses. It is possible to correct the absolute time information by recognizing that the information is received.

Here, when the initial absolute time information and the initial frame number are defined as ToD (0) and FN (0), the corrected absolute time information ToD (n) at the time of receiving FN (n) is represented by the following equation. 1> to correct it.

Here, n denotes the difference between the received frame number and the initial frame number, and T_frame means a frame period.

Thereafter, the terminal returns to step 305 to manage the absolute time information by using the corrected absolute time information and the local internal clock of the terminal.

In this case, when the user has applied for a reservation for a specific broadcast content, the terminal periodically checks the managed absolute time information, and then performs a terminal internal operation required for broadcast reception at the corresponding broadcast time to receive and receive a broadcast. Save or play back in real time.

Here, the correction of the absolute time information may be performed every frame number reception as described above, or may be performed each time a certain number of frame numbers are received.

Meanwhile, according to another embodiment of the present invention, the terminal may obtain absolute time information by using a broadcast message from the base station. Here, the broadcast message is, for example, a DCD message or an MCBCS MAP message, and the base station transmits the absolute time information to the terminal in the broadcast message. In other words, the GPS reception processing software block managing the absolute time information at the base station delivers the absolute time information to a call processing software block generating the DCD message or the MCBCS MAP message, and the call processing software block includes the same. The DCD message or the MCBCS MAP message is generated and transmitted to the terminal. Thus, the terminal may manage the absolute time information using the absolute time information received through the DCD message or the MCBCS MAP message and the internal clock of the terminal.

Here, the DCD message uses Quadrature Phase Shift Keying (QPSK) 1/12, and the MCBCS MAP message can obtain QPSK1 / 2 or more by utilizing macro diversity, so that the absolute time is obtained using the MCBCS MAP message. It is efficient to convey information. However, if the absolute time information is used for purposes other than MCBCS service, it should be included in the DCD message.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described. However, various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

1 is a diagram illustrating a network structure for providing an MCBCS service in a broadband wireless access system according to the present invention;

2 is a block diagram illustrating a configuration of an apparatus for acquiring and correcting absolute time information in a terminal of a broadband wireless access system according to an embodiment of the present invention;

3 is a flowchart illustrating a procedure of a method for obtaining and correcting absolute time information in a terminal of a broadband wireless access system according to an exemplary embodiment of the present invention.

Claims (26)

In the absolute time information correction method of the terminal, Obtaining initial absolute visual information, Receiving a frame number through a downlink map message; And correcting absolute time information by using the obtained initial absolute time information and the received frame number. The method of claim 1, And the initial absolute time information is obtained through a direct input of a user. The method of claim 1, wherein the initial absolute time information acquisition process comprises: Performing an initial network entry procedure, Requesting transmission of the initial absolute time information to an NTP server; Receiving the initial absolute time information from the NTP server. The method of claim 3, wherein Communication with the NTP server is via an application layer. The method of claim 1, And storing the obtained initial absolute time information and the corresponding initial frame number. The method of claim 5, wherein the absolute time information correction process, Calculating a product of a frame period with respect to a difference between the received frame number and the initial frame number, and correcting the absolute time information by calculating a sum of the calculated value and the initial absolute time information. . The method of claim 1, And managing the absolute time information by using the corrected absolute time information and a local internal clock of the terminal. The method of claim 7, wherein When a specific broadcast content is requested by the user, the process of periodically checking the managed absolute time information and performing an internal operation of a terminal required for receiving a broadcast at the corresponding broadcast time to receive and store the broadcast or to play the broadcast in real time. It further comprises a method. The method of claim 1, wherein the absolute time information correction process, Performing every frame number reception or whenever a certain number of frame numbers are received. In the absolute time information acquisition method of the terminal, Receiving a broadcast message including absolute time information from a base station, And extracting and storing the absolute time information from the broadcast message. The method of claim 10, The broadcast message is characterized in that at least one of a Downlink Channel Descriptor (DDC) message, a Multicast and BroadCast Service (MCBCS) MAP message. The method of claim 10, And managing the absolute time information by using the stored absolute time information and the internal clock of the terminal. The method of claim 12, When a specific broadcast content is requested by the user, the process of periodically checking the managed absolute time information and performing an internal operation of a terminal required for receiving a broadcast at the corresponding broadcast time to receive and store the broadcast or to play the broadcast in real time. It further comprises a method. In the absolute time information correction device of the terminal, An initial absolute time information acquisition unit for acquiring initial absolute time information; A frame number receiver for receiving a frame number through a downlink map message; And an absolute time information correcting unit configured to correct absolute time information by using the obtained initial absolute time information and the received frame number. The method of claim 14, wherein the initial absolute time information acquisition unit, And obtain the initial absolute time information through a direct input of a user. The method of claim 14, wherein the initial absolute time information acquisition unit, Means for performing an initial network entry procedure; Means for requesting transmission of the initial absolute time information to an NTP server; Means for receiving the initial absolute time information from the NTP server. The method of claim 16, And the communication with the NTP server is via an application layer. The method of claim 14, And a storage unit which stores the obtained initial absolute time information and the corresponding initial frame number. The method of claim 18, wherein the absolute time information correction unit, And calculating a product of a frame period with respect to the difference between the received frame number and the initial frame number, and correcting the absolute time information by calculating a sum of the calculated value and the initial absolute time information. The method of claim 14, And a local clock unit configured to manage the absolute time information by using the corrected absolute time information and a local internal clock of the terminal. The method of claim 20, When a specific broadcast content is requested for reservation by a user, the client program periodically checks the managed absolute time information, and performs a terminal internal operation for receiving a broadcast at the corresponding broadcast time to receive and store the broadcast or to play the broadcast in real time. Apparatus further comprising a. The method of claim 14, wherein the absolute time information correction unit, And correcting the absolute time information at every frame number reception or whenever a predetermined number of frame numbers are received. In the absolute time information acquisition device of the terminal, A receiving unit for receiving a broadcast message including absolute time information from the base station; And a storage unit for extracting and storing the absolute time information from the broadcast message. The method of claim 23, The broadcast message is at least one of a Downlink Channel Descriptor (DDC) message, a Multicast and BroadCast Service (MCBCS) MAP message. The method of claim 23, And a local clock unit configured to manage the absolute time information by using the stored absolute time information and a local internal clock of the terminal. The method of claim 25, When a specific broadcast content is requested for reservation by a user, the client program periodically checks the managed absolute time information, and performs a terminal internal operation for receiving a broadcast at the corresponding broadcast time to receive and store the broadcast or to play the broadcast in real time. Apparatus further comprising a.

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