KR20080103658A - Method and apparatus for generating broadcasting message in broadband wireless communication system - Google Patents

Abstract

A broadcasting message generating method in a broadband wireless communications system and an apparatus thereof using a control channel resource of a base station are provided to reduce a scanning section due to broadcasting message generating method in a broadband wireless communications system and an apparatus thereof using a control channel resource of a base station. Location information of terminals and neighboring base stations is renewed(400). The base stations and the terminals which are adjacent with reference to the location information are grouped as one group(402). A broadcasting message is transmitted by group(404). Neighboring base stations are base stations of independent systems and broadband wireless communications systems.

Description

Method and device for generating broadcast message in broadband wireless communication system {METHOD AND APPARATUS FOR GENERATING BROADCASTING MESSAGE IN BROADBAND WIRELESS COMMUNICATION SYSTEM}

1 is a view schematically showing the structure of a broadband wireless communication system according to the prior art;

2 is a flowchart of a handoff signal in a broadband wireless communication system according to the prior art;

3 is a diagram schematically illustrating an environment of a broadband wireless communication system for transmitting a broadcast message according to an embodiment of the present invention;

4 is a flowchart illustrating an operation of a base station for transmitting a broadcast message in a broadband wireless communication system according to an embodiment of the present invention;

5 is a flowchart illustrating a terminal operation for receiving a broadcast message in a broadband wireless communication system according to an embodiment of the present invention;

6 is a terminal device for transmitting a broadcast message in a broadband wireless communication system according to an embodiment of the present invention;

7 is a diagram of a base station apparatus for receiving a broadcast message in a broadband wireless communication system according to an embodiment of the present invention;

8 is a signal flow diagram for transmitting a broadcast message in a broadband wireless communication system according to an embodiment of the present invention.

The present invention relates to a broadband wireless communication system, and more particularly, to a method and apparatus for transmitting broadcast messages for each group by grouping adjacent terminals into one group according to the location information of the terminal and the adjacent base station.

1 is a diagram schematically illustrating a structure of a broadband wireless communication system according to the prior art.

Referring to FIG. 1, a broadband wireless communication system includes a plurality of base stations 101, 103, and 105 and a plurality of terminals 111 to 121. Depending on the implementation, a network entity (eg, a switching center) constituting the broadband wireless communication system may be further added, but the detailed description thereof will be omitted since it is not important to the present invention.

Each of the terminals 111 to 121 has a unique identification code, and is used for authentication when accessing a system, and then receives a service through a wireless link. In addition, the terminals support dual mode (eg, broadband wireless access service, wireless LAN service) service. However, the terminals 111 to 121 cannot simultaneously receive signals of both base stations of a system independent of each other. The base stations (101, 103, 105) exchanges signals with the terminals (111 to 121) using a wireless interface. It is in charge of wireless channel setup and handoff process. In addition, it connects between the terminals (111 to 121) and the switching center (not shown).

It is different from the previously set serving base station due to the movement of the subscriber stations 111 to 121 or the change in the radio wave environment, the sudden increase of the subscriber stations in a specific cell, etc. as time passes during communication. When a situation in which the communication environment with the neighboring base station becomes better, the subscriber station, the serving base station, and the neighboring target base stations must recognize the change of the communication environment efficiently and newly establish a communication path using the optimal base stations. For example, when the terminal 115 moves to the base station 103 in a state in which the terminal 115 is connected to the base station 101, it is necessary to change the communication path to access and communicate with the base station 103. Here, the base station 101 becomes a serving base station, and the base station 103 becomes a target base station. In addition, in order to change the communication path, a handoff procedure should be performed, which will be described with reference to FIG. 2.

2 is a flowchart illustrating a handoff signal in a broadband wireless communication system according to the related art.

Referring to FIG. 2, when handoff is required to a neighbor cell or a neighbor sector according to a change in a user's communication environment, the user terminal 200 determines neighbor base station information of the serving base station 202 in step 208. : Hereinafter referred to as "NBR-ADV" message is received. Here, the neighbor base station is a base station 204, a base station 206.

Thereafter, after receiving the MOB_NBR-ADV message in step 210, the terminal 200 transmits a SCNning interval allocation REQest message to the serving base station 202. .

Subsequently, the serving base station 202 transmits a scanning interval allocation response (SCN-RSP) message to the terminal 200 as a response message to the MOB_SCN-REQ message. At this time, the terminal 200 performs a series of scanning operations for measuring the state of the channel after synchronizing with the neighboring base station based on the MOB_SCN-RSP message. This scanning operation is performed sequentially with each corresponding base station according to the neighbor base station list included in the NBR-ADV message.

For example, after receiving the MOB_SCN-RSP message, the terminal 200 receives synchronization information from the base station 204 and information related to the base station 204 in step 216 during the M frame 214 after the M frame 214. Measure and collect. Similarly, during the N frame period 220, the synchronization information and the base station 206 related information are measured and collected from the base station 206 in step 218 from the base station 206. The terminal 200 synchronizes with neighboring base stations, and then receives data traffic from the serving base station 202 in step 222 during the P frame period 224. After the data traffic is transmitted, the scanning operations 226 and 228 are performed during the N frame period 230 of the neighboring base station again periodically or by an event.

As described above, in the prior art, the NBR-ADV message should be broadcast to all terminals in the cell, and thus should include information on all neighboring base stations that are likely to be handed off by terminals existing in the cell. Therefore, in an environment in which a plurality of indoor base stations exist in a cell as in a broadband wireless communication system, or in an environment in which multiple communication modes exist in the same space such as next-generation communication systems, where base stations of each mode are mixed, a hand between systems or modes is used. The number of base stations to be included in the NBR-ADV message increases to support the off. For example, a plurality of independent hotspot regions of a WLAN may be included in one cell in a broadband wireless communication system. Accordingly, in order to support inter-system handoff, there is a problem in that the capacity of the base station information message increases in the serving base station. In addition, in the terminal side, the scanning interval becomes longer as the number of base stations to be scanned increases. As a result, the data reception time from the existing base station is reduced by the scanning interval, resulting in a problem that the system usage efficiency is reduced and power consumption due to scanning is increased.

Therefore, when a plurality of base stations of other independent systems are included in a broadband wireless communication system, there is a need for a method and apparatus for improving system utilization efficiency by solving a problem of a long scanning interval.

Accordingly, an object of the present invention is to provide a method and apparatus for transmitting a broadcast message in a broadband wireless communication system.

Another object of the present invention is to provide a method and apparatus for improving system use efficiency by solving a long scanning interval problem when multiple base stations of another system independent from a base station are included in a broadband wireless communication system.

Another object of the present invention is to provide a method and apparatus for efficiently generating and transmitting a broadcast message periodically transmitted from a base station in a broadband wireless communication system based on location information of a terminal and neighboring base stations.

According to a first aspect of the present invention for achieving the above object, a method of operating a base station for generating a broadcast message in a broadband wireless communication system, updating the location information of neighboring base stations and terminals, and the location information The method includes grouping neighboring base stations and terminals into one group with reference to each other, and transmitting a broadcast message for each group.

According to a second aspect of the present invention for achieving the above object, a method for operating a terminal for transmitting a broadcast message in a broadband wireless communication system, the method comprising: transmitting location information to a base station and transmitting by group according to the location information; Receiving a broadcast message, and acquiring information on a scanning target base station using the broadcast message.

According to a third aspect of the present invention for achieving the above object, in a broadband wireless communication system for generating a broadcast message, updating the location information of neighboring base stations and terminals, and with the adjacent base stations with reference to the location information Grouping terminals into a group, receiving a base station transmitting broadcast messages for each group, transmitting location information to the base station and receiving a broadcast message transmitted for each group according to the location information, and scanning using the broadcast message It characterized in that it comprises a terminal for obtaining the target base station information.

According to a fourth aspect of the present invention for achieving the above objects, there is provided a base station apparatus for generating a broadcast message in a broadband wireless communication system, comprising: a location information management unit for updating location information of neighboring base stations and terminals; A grouping unit for grouping adjacent base stations and terminals into one group with reference to, and a message generator for transmitting a broadcast message for each group.

According to a fifth aspect of the present invention for achieving the above objects, there is provided a terminal apparatus for transmitting a broadcast message in a broadband wireless communication system, comprising: a location generating unit for transmitting location information to a base station, and group by group according to the location information; And a message processing unit for receiving the transmitted broadcast message, and a control unit for acquiring scanning target base station information using the broadcast message.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of related known functions or configurations will be omitted when it is determined that the detailed description may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

Hereinafter, a method and apparatus for efficiently generating and transmitting a broadcast message by grouping adjacent terminals according to location information of neighboring base stations and terminals of a serving base station in a broadband wireless communication system will be described.

3 is a diagram schematically illustrating an environment of a broadband wireless communication system for transmitting a broadcast message according to an embodiment of the present invention. General operation descriptions of the terminals 310 to 316 and the base stations 300 to 304 are the same as those of FIG. 1, and thus, a detailed description thereof will be omitted and the operation description according to the present invention will be mainly described. In this case, the base stations 330 and 332 are base stations operating independently from the base stations 300 to 304 in different systems.

Referring to FIG. 3, system 1 is a broadband wireless communication system serving a wider area than system 2 and may include a service area of another system (eg, system 2). For example, the system 2 is a system serving a relatively narrow area as compared to the system, for example, a hot spot area such as a wireless LAN. In this case, it is assumed that a plurality of base stations of System 2 exist in each cell region of System 1, and the base station information of System 1 is transmitted in the same manner as in the conventional method, and the base station information of System 2 receives the proposed method. Suppose it passes through. In addition, it is assumed that the initial connection of the user terminal is made through the system 1. That is, it is assumed that a plurality of APs (Access Points) capable of WLAN service exist in the broadband wireless communication system.

When the user terminals 310 to 316 are connected to the system 1, the operation of the base station, the base station 300 of the system 1 is the base station 1 (330), the base station 2 (332) of the system 2 belonging to its cell area By using the location information of) and the location information of the user terminals (310 to 316) to group the adjacent user terminals and the base stations of the other system into a group. In FIG. 3, the base station 1 330 and the terminals 310 and 312 of the system 2 refer to a group (hereinafter, referred to as “group 1”), and the base station 2 332 and the terminals 314 of the system 2. , 316 creates another group (hereinafter referred to as "group 2"). The base station of the system 1 generates NBR-ADV messages to be transmitted to each group based on the grouping result. The NBR-ADV1 message 318 includes information of the base station 1 330 of the system 2 in close proximity to the terminals 310 and 312. The NBR-ADV2 message 320 includes information of the base station 2 332 of the system 2 in close proximity to the terminals 314 and 316. The serving base station transmits the NBR-ADV1 message to the members of group 1 using the multicasting scheme, and delivers the NBR-ADV2 message to the members of group 2, respectively. This operation is repeated based on the cycle determined by the system.

In operation of the terminal, the user terminals receive different NBR-ADV messages generated based on the location information of each terminal from the base station 300 of the system 1 through multicasting. UEs may perform a preliminary procedure for handoff through scanning of neighbor BSs based on the NBR-ADV received by the UEs. For example, the terminals 310 and 312 of the group 1 receiving the NBR-ADV 1 message scan only the base station 330 by referring to the base station 330 information of the system 2 in the NBR-ADV 1 message. Similarly, the terminals 314 and 316 of the group 2 receiving the NBR-ADV 2 message scan only the base station 332 by referring to the base station 332 information of the system 2 in the NBR-ADV 2 message.

In this case, when the user terminal is connected to system 2, the user terminal connected to system 2 by handing off system 1 to system 2 may no longer receive the NBR-ADV message of system 1. This is not a problem when the base station of system 2 can transmit NBR-ADV message by itself. However, when using an inexpensive base station such as a wireless LAN, the user terminal cannot receive information about the neighbor base station of system 1 from system 2. As a result, there is a problem handing off to System 1 again. To do this, the terminal handing off from System 1 to System 2 stores the last received NBR-ADV message and when the situation occurs that requires handoff back to System 1, the candidate stations of System 1 are scanned using the stored message. Can be specified.

4 is a flowchart illustrating an operation of a base station for transmitting a broadcast message in a broadband wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 4, first, a base station is adjacent to each other using a satellite positioning system (GPS) or location-based services (LBS) in step 400. Update location information of base stations and terminals. The LBS technology includes Cell-ID, Enhanced Observed Time Difference (E-OTD), Assisted-GPS (A-GPS), A-GPS-Based Hybrids, and pCell techniques. The Cell-ID method is a method of determining the location of a base station as the location of the terminal when the terminal is registered with the base station using an identifier assigned to the base station. The E-OTD method is a method of determining a location by measuring a relative arrival time difference of a signal transmitted from a base station by a positioning device built in a terminal. The A-GPS method is a method of determining a location of a terminal by measuring a signal transmitted from three or more satellites by a GPS positioning device built in the terminal. The pCell technology is a network location based method.

Thereafter, the base station proceeds to step 402 to generate NBR-ADV messages for each group by grouping adjacent terminals and neighbor base stations into one group using the updated location information. Here, by transmitting the NBR-ADV message by grouping adjacent terminals and base stations adjacent to the terminals in a group, the scanning interval lengthened by performing the scanning operation on only the base stations adjacent to the terminals can be reduced.

In step 404, the base station multicasts the generated NBR-ADV message for each group according to a period or an event.

In step 406, the base station determines whether all group transmissions are completed and continues to transmit the group NBR-ADV message until completion.

If the transmission is completed, the steps 400 to 404 are repeated.

The algorithm of the present invention is then terminated.

5 is a flowchart illustrating a terminal operation for receiving a broadcast message in a broadband wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the terminal first transmits location information to the base station using a GPS or LBS based location information providing service in step 500.

In step 502, the terminal receives an NBR-ADV message generated based on neighboring terminals and base stations from the base station.

Thereafter, the terminal acquires base station information by performing a scanning procedure with corresponding base stations with reference to neighbor base station information included in the NBR-ADV message received in step 504.

Thereafter, the terminal determines whether a handoff is necessary according to the handoff procedure in step 506, and repeats steps 500 to 504 when the handoff is not required.

If a handoff is required, the terminal determines whether a handoff occurs in the same system in step 508, and if a handoff occurs in the same system, the terminal proceeds to step 510 and hand is determined by a procedure determined in the same system. Perform off. For example, the terminal may need a handoff in a broadband wireless communication system, or may perform a handoff to a hotspot area of a WLAN in the broadband wireless communication system.

On the other hand, if a handoff does not occur in the same system, that is, when moving to another system (for example, when moving to a hotspot area of a WLAN in a broadband wireless communication system), the terminal proceeds to step 512 and the existing system. Stores neighbor base station information. This allows the terminal to attempt handoff later using the stored neighbor base station information when the terminal needs to handoff back to the previous system.

In step 514, the terminal performs handoff to the corresponding heterogeneous system.

The algorithm of the present invention is then terminated.

6 is a diagram illustrating a base station apparatus for transmitting a broadcast message in a broadband wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 6, the base station includes an RF processor 601, an ADC 603, an OFDM demodulator 605, a decoder 607, a message processor 609, a controller 611, a handoff unit 613, Including position information generator 615, message generator 617, encoder 619, OFDM modulator 621, DAC 623, RF processor 625, switch 627, time controller 629 It is composed.

First, the time controller 629 controls the switching operation of the switch 627 based on time synchronization. For example, if the signal receiving section, the time controller 629 controls the switch 627 so that the antenna and the RF processor 601 of the receiving end is connected, and if the signal transmitting section, the time controller 629 The switch 627 is controlled so that the RF processor 625 is connected.

During the reception period, the RF processor 601 converts a radio frequency (RF) signal received through an antenna into a baseband analog signal. The ADC 603 converts an analog signal from the RF processor 601 into sample data and outputs the sample data. The OFDM demodulator 605 converts the sample data output from the ADC 603 into data of a frequency domain by fast Fourier transform (FFT), and selects and outputs data of subcarriers to be actually received from the data of the frequency domain. . The decoder 607 demodulates and decodes the data from the OFDM demodulator 605 according to a predetermined modulation level (MCS level).

The message processor 609 decomposes the control message input from the decoder 607 and provides the result to the controller 611. The controller 611 performs corresponding processing on the information from the message processor 609, and generates and transmits information to be transmitted to the message generator 617. The message generator 617 generates a message with various types of information provided from the controller 611 and outputs the message to the encoder 619 of the physical layer. The encoder 619 codes and modulates the data from the message generator 617 according to a predetermined modulation level (MCS level). The OFDM modulator 621 outputs sample data (OFDM symbols) by performing IFFT (Inverse Fast Fourier Transform) on the data from the encoder 619. The DAC 623 converts the sample data into an analog signal and outputs the analog signal. The RF processor 625 converts an analog signal from the DAC 623 into a radio frequency (RF) signal and transmits the same through an antenna.

The location information generator 615 generates current location information through a GPS or LBS location-based service and transmits the current location information to the base station under the control of the controller 611. In this case, the location information generation unit 615 may generate location information using Cell-ID, E-OTD, A-GPS, A-GPS-Based Hybrids, pCell technique, or the like.

The handoff unit 613 performs a handoff procedure by referring to a broadcast message from the terminal by the control unit 611. For example, it is received and attempts a handoff procedure using information of neighboring base stations via a MOB_NBR-ADV message.

In the above configuration, the controller 611 is a protocol controller, and controls the message processor 609, the message generator 617, the location information generator 615, and the handoff unit 613. That is, the controller 611 may perform the functions of the message processor 609, the location information generator 615, the handoff unit 613, and the message generator 617. In the present invention, it is separately configured to describe each function separately. Therefore, in actual implementation, all of them may be configured to be processed by the controller 611, and only some of them may be configured to be processed by the controller 611. In addition, the control unit 611 receives the necessary information during the protocol processing to the corresponding component of the physical layer, or generates a control signal to the corresponding component of the physical layer.

Next, the operation of the terminal according to the present invention will be described based on the configuration of FIG. 6. The user terminals receive different NBR-ADV messages generated based on the location information of each terminal from the base station through multicasting. The terminal may proceed with the pre-process for the handoff through scanning for the neighbor base stations based on the NBR-ADV received by the terminal. In addition, the terminal stores the NBR-ADV message finally received before performing the handoff, and prepares for a situation in which the terminal needs to handoff to the existing system again.

7 is a diagram illustrating a terminal device for receiving a broadcast message in a broadband wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 7, the base station includes an RF processor 701, an ADC 703, an OFDM demodulator 705, a decoder 707, a message processor 709, a controller 711, a location information manager 713, And a grouping unit 715, a message generator 717, an encoder 719, an OFDM modulator 717, a DAC 721, an RF processor 725, a switch 727, and a time controller 729. . The RF processor 701, the ADC 703, the OFDM demodulator 705, the decoder 707, the message processor 709, the controller 711, the message generator 717, the encoder 719, and the OFDM modulator. 721, the DAC 723, the RF processor 725, the switch 727, and the time controller 729 are the same as those described with reference to FIG. 6, and thus detailed descriptions thereof will be omitted.

The location information management unit 713 collects and stores terminal location information and location information of neighboring base stations from each of the terminals through a GPS or LBS location-based service. In addition, the grouping unit 715 provides location information of the terminals and the neighbor base stations.

The grouping unit 715 refers to the location information of the terminals and the neighboring base stations from the location information management unit 713, groups the neighboring base stations and the terminals into a group to control the list of terminals included in the group. 711 is provided to the message generator 717. When grouping, the grouping unit 715 sets neighboring terminals and neighboring base stations into one group.

Next, the operation of the base station according to the present invention will be described based on the configuration of FIG. 7.

The base station uses the location information of neighboring base stations in its cell area and the location information of the user terminals to group the terminals in close proximity with the base stations of other systems into a group. The base station generates each NBR-ADV message to be transmitted to each group based on the grouping result. The base station transmits the group-specific NBR-ADV messages to the members of the group by using the multicasting scheme.

8 is a signal flow diagram for transmitting a broadcast message in a broadband wireless communication system according to an embodiment of the present invention.

Referring to FIG. 8, in step 820, the base station 800 updates location information from neighbor base stations 802 and 808 and terminals 804, 806 and 810 through a GPS or LBS based location based service.

Thereafter, the base station 800 groups adjacent terminals and base stations into one group by using the updated location information in step 822, and generates a broadcast message for each corresponding group.

Thereafter, the base station 800 multicasts the broadcast message generated for each group in steps 824 and 826 to corresponding terminals.

Thereafter, the base station 800 receives location information from neighboring base stations and terminals in step 830 and updates the location information as in step 820.

The algorithm of the present invention is then terminated.

Although a system environment including hotspot sections of a plurality of WLANs in a broadband wireless communication system of the present invention has been described as an example, an environment in which a plurality of indoor base stations exist in a cell or a next-generation communication system as in a broadband wireless communication system As such, there are several communication modes in the same space, so that the present invention can be applied to an environment where base stations of each mode are mixed.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible 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.

As described above, the NBR-ADV message periodically transmitted from the base station in the broadband wireless communication system is transmitted by grouping based on the location information of the user terminal and neighboring base stations, etc. The scanning interval can be reduced. In addition, this can effectively use the control channel resources of the base station and has the advantage of saving time and power required for scanning.

Claims (18)

A method of operating a base station for generating a broadcast message in a broadband wireless communication system, Updating location information of neighboring base stations and terminals; Grouping adjacent base stations and terminals into a group with reference to the location information; And transmitting a broadcast message for each group. The method of claim 1, Wherein said neighbor base stations are base stations of a system independent of said broadband wireless communication system. The method of claim 1, The grouping method is characterized in that the neighboring terminals and the base stations are set to one group. The method of claim 1, The broadcast message is generated according to a group, characterized in that for generating by group. A method of operating a terminal for transmitting a broadcast message in a broadband wireless communication system, Transmitting location information to the base station; Receiving a broadcast message transmitted for each group according to the location information; And acquiring scanning target base station information by using the broadcast message. The method of claim 5, And performing a handoff according to the obtained scanning target base station information. The method of claim 6, The process of performing the handoff according to the acquired scanning target base station information Determining whether the handoff is within the same system; When not in the same system, storing neighbor base station information of the existing system and performing a handoff to a heterogeneous system. The method of claim 7, wherein When a handoff occurs from a heterogeneous system to a previous system. And performing a handoff using the stored previous information. In the broadband wireless communication system for generating a broadcast message, A base station for updating location information of neighboring base stations and terminals, grouping neighboring base stations and terminals into a group with reference to the location information, and transmitting a broadcast message for each group; And a terminal for transmitting location information to the base station, receiving a broadcast message transmitted for each group according to the location information, and acquiring scanning target base station information using the broadcast message. The method of claim 9, And the broadcast message includes information of neighbor base stations. A base station apparatus for generating a broadcast message in a broadband wireless communication system, A location information management unit for updating location information of neighboring base stations and terminals; A grouping unit which groups adjacent base stations and terminals into a group with reference to the location information; And a message generator for transmitting broadcast messages for each group. The method of claim 11, And said neighbor base stations are base stations of a system independent of said broadband wireless communication system. The method of claim 11, The grouping is characterized in that the neighboring terminals and the base station to set up as a group. The method of claim 11, And the broadcast message is generated for each group according to the grouping result. A terminal device for transmitting a broadcast message in a broadband wireless communication system, A location generator for transmitting location information to the base station; A message processor for receiving a broadcast message transmitted for each group according to the location information; And a controller configured to acquire scanning target base station information using the broadcast message. The method of claim 15, And a handoff unit performing a handoff according to the acquired scanning target base station information. The method of claim 16, The handoff part Determining whether the handoff is in the same system, and when the information is not in the same system, storing neighbor base station information of the existing system and performing handoff to a heterogeneous system. The method of claim 17, When the handoff occurs from the heterogeneous system to the previous system. And perform a handoff using the stored previous information.

Images