Patent Abstract:
A base station designates an identification symbol section in each communication frame in order to identify a plurality of transceivers, transmits a predetermined transceiver identification signal through subcarriers granted to the plurality of transceivers by granting a combination of subcarriers to be used in an identification symbol section to each of the plurality of transceivers, generates and stores terminal connection information for each of the plurality of transceivers by receiving information on evaluation of reception quality for the transceiver from the terminal and using the received information, and allocates a communication resource so as to use the subcarrier of the transceiver connected with the terminal for communicating with the terminal.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2009-0128404 filed in the Korean Intellectual Property Office on Dec. 21, 2009, the entire contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    (a) Field of the Invention 
         [0003]    The present invention relates to a method for communication channel control. More particularly, the present invention relates to a method for communication channel control to provide a location-based communication service. 
         [0004]    (b) Description of the Related Art 
         [0005]    The known location-based communication service is provided based on an estimated distance between a base station and a terminal by mounting an additional location-based module in the terminal or using received signal strength. 
         [0006]    According to the known service, however, the location recognition module should be mounted on the terminal in order to provide the location-based service. Further, it is difficult to estimate an accurate location of the terminal from the estimated distance between the base station and the terminal. 
         [0007]    The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention has been made in an effort to provide a method for communication channel control having advantages of providing a location-based communication service to a terminal or a mobile station without a location recognition module. 
         [0009]    An exemplary embodiment of the present invention provides a method for communication channel control for a base station including a plurality of transceivers to provide a location-based service to a terminal, that includes: designating an identification symbol section in a communication frame in order to identify the plurality of transceivers and transmitting a predetermined transceiver identification signal through subcarriers granted to the plurality of transceivers by granting a combination of subcarriers to be used in the identification symbol section to each of the plurality of transceivers; generating and storing terminal connection information for each of the plurality of transceivers by receiving information on evaluation of reception quality for the transceiver from the terminal and using the received information; and allocating a communication resource so as to use the subcarrier of the transceiver connected with the terminal for communicating with the terminal. 
         [0010]    Another embodiment of the present invention provides a method for communication channel control for a terminal to receive a communication access service based on the location of the terminal from a base station including a plurality of transceivers, that includes: receiving a transceiver identification symbol signal included in a downlink frame section of a communication frame from the base station; evaluating the quality of a received signal of each of the plurality of transceivers by using a combination of subcarriers for each of the plurality of transceivers; and transmitting transceiver identification result information including an evaluation result of the quality of the received signal. 
         [0011]    Yet another embodiment of the present invention provides a method for communication channel control for a communication system including a plurality of base stations to provide a mobile access service using single frequency band, the method includes: allocating channels to the plurality of transceivers so that a plurality of transceivers included in a first base station among the plurality of base stations use different channels from adjacent transceivers taking charge of adjacent communication areas; allowing the plurality of transceivers to transmit identification signals to the terminal by using subcarriers of the allocated channels by disposing a transceiver identification symbol section in a downlink frame depending on the channels allocated to the plurality of transceivers; generating and storing terminal connection information for the plurality of transceivers on the basis of the transceiver identification result information received from the terminal; and allocating a channel resource so as to transmit and receive signals through the transceiver connected to the terminal depending on the terminal connection information. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a service conceptual diagram of a base station system according to an embodiment of the present invention; 
           [0013]      FIG. 2  is a diagram illustrating a configuration of a base station system according to another embodiment of the present invention; 
           [0014]      FIG. 3  is a diagram illustrating a structure of an OFDMA frame according to an embodiment of the present invention; 
           [0015]      FIG. 4  is a diagram illustrating a method for generating connection information according to an embodiment of the present invention; 
           [0016]      FIG. 5  is a diagram illustrating one example of a configuration of a transceiver identification symbol according to an embodiment of the present invention; 
           [0017]      FIG. 6  is a diagram illustrating a method for updating connection information according to an embodiment of the present invention; 
           [0018]      FIG. 7  is a diagram illustrating a configuration of an electronic toll collection system according to another embodiment of the present invention; and 
           [0019]      FIG. 8  is a diagram illustrating a configuration of a single frequency network at the roadside according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0020]    In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification. 
         [0021]    In the specification, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. 
         [0022]    In the specification, a mobile station (MS) may designate a terminal, a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), user equipment (UE), an access terminal (AT), etc., and may include the entire or partial functions of the mobile terminal, the subscriber station, the portable subscriber station, the user equipment, etc. 
         [0023]    In the specification, a base station (BS) may designate an access point (AP), a radio access station (RAS), a node B, a base transceiver station (BTS), a mobile multihop relay (MMR)-BS, etc., and may include the entire or partial functions of the access point, the radio access station, the node B, the base transceiver station, the MMR-BS, etc. 
         [0024]    Hereinafter, a method for communication channel control for providing a location-based communication service according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
         [0025]    First, a service concept of a base station system according to an embodiment of the present invention will be described with reference to  FIG. 1 . 
         [0026]      FIG. 1  is a service conceptual diagram of a base station system according to an embodiment of the present invention. 
         [0027]    As shown in  FIG. 1 , a base station system  100  includes a base station  110  and a plurality of transceivers, i.e., a first transceiver  131 , a second transceiver  132 , a third transceiver  133 , and a fourth transceiver  134 . 
         [0028]    The base station  110  divides a communication area of the base station system  100  into a plurality of subareas, i.e., a first subarea  10 , a second subarea  20 , a third subarea  30 , and a fourth subarea  40  in accordance with a service characteristic and disposes the plurality of transceivers in the plurality of subareas, respectively, for communication that is suitable for service characteristics of the subareas. 
         [0029]    The first transceiver  131  communicates with a mobile station located at the first subarea  10 . The second transceiver  132  communicates with a mobile station located at the second subarea  20 . The third transceiver  133  communicates with a mobile station located at the third subarea  30 . The fourth transceiver  134  communicates with a mobile station located at the fourth subarea  40 . 
         [0030]    Next, referring to  FIG. 2 , a configuration of a base station system according to another embodiment of the present invention will be described. 
         [0031]      FIG. 2  is a diagram illustrating a configuration of a base station system according to another embodiment of the present invention. 
         [0032]    As shown in  FIG. 2 , a base station system  200  includes a connection information table  210 , a controller  230 , and a plurality of transceivers  250 . In  FIG. 2 , the base station system  200  includes four transceivers, i.e., a first transceiver  251 , a second transceiver  252 , a third transceiver  253 , and a fourth transceiver  254 , but may not be limited thereto. 
         [0033]    The connection information table  210  stores connection information between a transceiver and a mobile station (also referred to as “MS” above), that is, ranking information of a mobile station that each transceiver will service. At this time, the connection information between the plurality of transceivers  250  and the plurality of mobile stations  11  to  16 , which is stored in the connection information table  210 , may be based on Table 1. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Classification 
                 First ranking 
                 Second ranking 
               
               
                   
               
             
             
               
                 First transceiver 
                 MS 1 , MS 3 , MS 4   
                   
               
               
                 Second transceiver 
                   
                 MS 1 , MS 2 , MS 3 , MS 4   
               
               
                 Third transceiver 
                 MS 2   
                 MS 5 , MS 6   
               
               
                 Fourth transceiver 
                 MS 5 , MS 6   
               
               
                   
               
             
          
         
       
     
         [0034]    The controller  230  configures the frame depending on a time resource and a frequency resource allocated to the base station system  200 , manages the connection information of the connection information table  210  by using a transceiver identification symbol, and provides a location-based communication access service to the plurality of mobile stations  11  to  16  by using the connection information of the connection information table  210 . 
         [0035]    Each of the plurality of transceivers  250  forms an independent communication area and communicates with a mobile station located at the corresponding communication area. Herein, a plurality of communication areas formed by the plurality of transceivers  250  may correspond to the plurality of subareas described in  FIG. 1 . 
         [0036]    The first transceiver  251  forms a first communication area  251   a  and may communicate with the first mobile station (MS 1 )  11 , the third mobile station (MS 3 )  13 , and the fourth mobile station (MS 4 )  14  that are located at the first communication area  251   a.    
         [0037]    The second transceiver  252  forms a second communication area  252   a.    
         [0038]    The third transceiver  253  forms a third communication area  253   a  and may communicate with the second mobile station (MS 2 )  12  that is located at the third communication area  253   a.    
         [0039]    The fourth transceiver  254  forms a fourth communication area  254   a  and may communicate with the fifth mobile station (MS 6 )  15  and the sixth mobile station (MS 6 )  16  that are located at the fourth communication area  254   a.    
         [0040]    Next, referring to  FIG. 3 , a structure of a frame following an orthogonal frequency division multiple access (hereinafter referred to as “OFDMA”) method for providing a location-based communication service according to an embodiment of the present invention will be described. 
         [0041]      FIG. 3  is a diagram illustrating a structure of an OFDMA frame according to an embodiment of the present invention. 
         [0042]    As shown in  FIG. 3 , an OFDMA frame is constituted by a plurality of orthogonal frequency division multiplexing symbols (hereinafter referred to as “OFDM symbols”) determined depending on a plurality of time symbols S 0 , S 1 , S 2 , S 3 , . . . , S n-1  and a plurality of subcarriers SC O  SC 1 , SC 2 , SC 3 , SC 4 , . . . , SC m-1 , and includes a downlink frame section  310 , a first protection section  330 , an uplink frame section  350 , and a second protection section  370 . Herein, protection sections may be also called as “guide interval” The downlink frame section  310  is a section where a signal is transmitted from the base station system  200  to the mobile station, and includes a preamble section (referred to as “PS” in  FIG. 3 )  311 , a control information section (referred to as “CIS” in  FIG. 3 )  313 , a transceiver identification symbol section (referred to as “TISS” in  FIG. 3 )  315 , and a message data channel-downlink (referred to as “MDC-Dn” in  FIG. 3 )  317 . 
         [0043]    The preamble section  311  indicates the start of the OFDMA frame. 
         [0044]    The control information section  313  includes system control information (common control), basic information on a service provided by the base station system  200 , and acknowledge information on a message data channel-uplink (hereinafter referred to as “MDC-Up”) of the previous OFDMA frame. 
         [0045]    The transceiver identification symbol section  315  includes a transceiver indentifying symbol for the mobile station to measure the quality of the signal transmitted from each of the transceivers. 
         [0046]    The message data channel-downlink  317  includes broadcast-type information that all the mobile stations can receive, and individual information data transmitted to the individual mobile stations. 
         [0047]    The first protection section (referred to as “FPS” in  FIG. 3 )  330  partitions a downlink frame section  310  and an uplink frame section  350 . 
         [0048]    The uplink frame section  350  is a section where a signal is transmitted from the mobile station to the base station system  200 , and includes acknowledge information section (referred to as “ACK” in  FIG. 3 )  351 , a message data channel-uplink (MDC-Up)  353 , and random association channels (referred to as “ACTS” in  FIG. 3 )  355 . 
         [0049]    The acknowledge information section  351  includes acknowledge information on the individual information data of the downlink data channel  317 . The message data channel-uplink (MDC-Up)  353  includes the uplink individual information data transmitted to the base station system  200 . The random association channel  355  includes random access request information used to request, maintain, or change link access. The second protection section (referred to as “SPS” in  FIG. 3 )  370  notifies that the OFDMA frame is terminated. 
         [0050]    Next, referring to  FIG. 4 , a method for a base station system to generate connection information between a transceiver and a mobile station in order to allocate a channel to the mobile station will be described. 
         [0051]      FIG. 4  is a diagram illustrating a method for generating connection information according to an embodiment of the present invention. 
         [0052]    As shown in  FIG. 4 , first, a controller  230  of a base station system  200  allocates a plurality of subcarriers to a plurality of transceivers  250  by determining the subcarriers for the plurality of transceivers  250  on the basis of the frequency resource allocated to the base station system  200 , that is, the plurality of subcarriers (S 101 ). 
         [0053]    Next, the controller  230  of the base station system  200  configures an OFDMA frame inserted with a transceiver identification symbol based on OFDMA (S 103 ). 
         [0054]    At this time, the OFDMA frame is constituted by a plurality of OFDM symbols, and includes a downlink frame section where a signal is transmitted from the base station system  200  to the mobile station and an uplink frame section where the signal is transmitted from the mobile station to the base station system  200 . The downlink frame section includes a transceiver identification symbol section including a plurality of transceiver identification symbols. Further, the transceiver identification symbol section may correspond to the preamble section. 
         [0055]    Thereafter, the controller  230  of the base station system  200  generates a plurality of communication frames corresponding to the plurality of transceivers  250 , respectively, on the basis of the combination of the subcarriers for the plurality of transceivers  250  (S 105 ). 
         [0056]    At this time, the controller  230  may generate a first communication frame including a symbol corresponding to a subcarrier allocated to a first transceiver  251  among the plurality of transceiver identification symbols, may generate a second communication frame including a symbol corresponding to a subcarrier allocated to a second transceiver  252  among the plurality of transceiver identification symbols, may generate a third communication frame including a symbol corresponding to a subcarrier allocated to a third transceiver  253  among the plurality of transceiver identification symbols, and may generate a fourth communication frame including a symbol corresponding to a subcarrier allocated to a fourth transceiver  254  among the plurality of transceiver identification symbols. 
         [0057]    Next, the base station system  200  transmits the plurality of communication frames to a first mobile station  11  through the plurality of transceivers  250  (S 107 ). 
         [0058]    At this time, the first transceiver  251  may transmit the first communication frame through the subcarrier allocated to the first transceiver  251 , the second transceiver  252  may transmit the second communication frame through the subcarrier allocated to the second transceiver  252 , the third transceiver  253  may transmit the third communication frame through the subcarrier allocated to the third transceiver  253 , and the fourth transceiver  254  may transmit the fourth communication frame through the subcarrier allocated to the fourth transceiver  254 . 
         [0059]    Thereafter, the first mobile station  11  calculates the quality of a received signal between each transceiver and the first mobile station  11  on the basis of the plurality of received communication frames (S 109 ). 
         [0060]    At this time, the mobile station  11  may calculate the quality of a received signal between the first transceiver  251  and the first mobile station  11  on the basis of the transceiver identification symbol included in the first communication frame, may calculate the quality of a received signal between the second transceiver  252  and the first mobile station  11  on the basis of the transceiver identification symbol included the second communication frame, may calculate the quality of a received signal between the third transceiver  253  and the first mobile station  11  on the basis of the transceiver identification symbol included in the third communication frame, and may calculate the quality of a received signal between the fourth transceiver  254  and the first mobile station  11  on the basis of the transceiver identification symbol included in the fourth communication frame. 
         [0061]    Further, the quality of the received signal between each transceiver and the first mobile station  11  may correspond to a value of a received signal strength indication (hereinafter referred to as “RSSI”). Further, the first mobile station  11  may calculate the quality of the received signal between each transceiver and the first mobile station  11  in accordance with Equation 1. 
         [0000]    
       
         
           
             
               
                 
                   
                     Q 
                     t 
                   
                   = 
                   
                     
                       ∑ 
                       
                         k 
                         ∈ 
                         
                           K 
                           t 
                         
                       
                     
                      
                     
                         
                     
                      
                     
                       
                          
                         
                           r 
                           k 
                         
                          
                       
                       2 
                     
                   
                 
               
               
                 
                   ( 
                   
                     Equation 
                      
                     
                         
                     
                      
                     1 
                   
                   ) 
                 
               
             
           
         
       
     
         [0062]    At this time, factors of Equation 1 follow Table 2. 
         [0000]    
       
         
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
             
             
               
                 m 
                 Number of subcarriers configuring a transceiver 
               
               
                   
                 identification symbol 
               
               
                 N 
                 Number of transceivers controlled by a base station 
               
               
                 I = {0, 1, . . . , m-1} 
                 Set of subcarrier indexes configuring the transceiver 
               
               
                   
                 identification symbol 
               
               
                 T = {0, 1, . . . , N-1} 
                 Set of indexes of transceivers controlled by the  
               
               
                   
                 base station 
               
               
                 K t   
                 Combination of subcarriers allocated to a  
               
               
                   
                 transceiver t for identification the transceiver 
               
               
                 r i   
                 Level of a received signal of an i-th subcarrier after  
               
               
                   
                 fast Fourier transformation by receiving the  
               
               
                   
                 received transceiver identification symbol, i ε I 
               
               
                 Q t   
                 Received signal quality of the transceiver t 
               
               
                   
               
             
          
         
       
     
         [0063]    Next, the first mobile station  11  transmits signal quality information on the first mobile station  11 , which includes the quality of the received signal between each transceiver and the first mobile station  11 , to the base station system  200  (S 111 ). At this time, the first mobile station  11  may transmit the signal quality information through the random association channel. 
         [0064]    Thereafter, the controller  230  of the base station system  200  determines an optimal transceiver for the first mobile station  11  on the basis of the received signal quality information (S 113 ). At this time, the controller  230  may determine a transceiver having the best signal quality for the mobile station  11 , that is, the optimal transceiver, in accordance with Equation 2 on the basis of the received signal quality included in the signal quality information. 
         [0000]    
       
         
           
             
               
                 
                   j 
                   = 
                   
                     arg 
                      
                     
                         
                     
                      
                     
                       
                         max 
                         
                           i 
                           ∈ 
                           I 
                         
                       
                        
                       
                         Q 
                         i 
                       
                     
                   
                 
               
               
                 
                   ( 
                   
                     Equation 
                      
                     
                         
                     
                      
                     2 
                   
                   ) 
                 
               
             
           
         
       
     
         [0065]    In Equation 2, represents the index of the optimal transceiver. 
         [0066]    Next, the controller  230  of the base station system  200  generates connection information between the transceiver and the mobile station on the basis of the determined optimal transceiver for the first mobile station  11  (S 115 ). At this time, the controller  230  may store the connection information between the transceiver and the mobile station in a connection information table  210 . 
         [0067]    As above, the base station system  200  receives the signal quality information from a plurality of mobile stations, and determines an optimal transceiver for each of the plurality of mobile stations to complete the connection information between the transceiver and the mobile station. Further, when the base station system  200  allocates a channel to a predetermined mobile station in accordance with the completed connection information, the base station system  200  may allocate the channel to the mobile station so that the corresponding mobile station performs communication through the optimal transceiver. 
         [0068]    Next, referring to  FIG. 5 , a configuration of a transceiver identification symbol by a combination of subcarriers according to an exemplary embodiment of the present invention will be described. 
         [0069]      FIG. 5  is a diagram illustrating one example of a configuration of a transceiver identification symbol according to an embodiment of the present invention. 
         [0070]    As shown in  FIG. 5 , the transceiver identification symbol section  315  is allocated as one time symbol section S j . 
         [0071]    When subcarriers allocated to the first transceiver  251  are SC O , SC 4 , SC 8 , and SC m-4 , a transceiver identification symbol that the first transceiver  251  will transmit is shown in  FIG. 4 . 
         [0072]    When subcarriers allocated to the second transceiver  252  are SC 1 , SC 5 , SC 9 , and SC m-3 , a transceiver identification symbol that the second transceiver  252  will transmit is shown in  FIG. 4 . 
         [0073]    When subcarriers allocated to the third transceiver  253  are SC 2 , SC 6 , SC 10 , and SC m-2 , a transceiver identification symbol that the third transceiver  253  will transmit is shown in  FIG. 4 . 
         [0074]    When subcarriers allocated to the fourth transceiver  254  are SC 3 , SC 7 , SC 11 , and SC m-1 , a transceiver identification symbol that the fourth transceiver  254  will transmit is shown in  FIG. 4 . 
         [0075]    Next, referring to  FIG. 6 , a method for a base station system to update connection information between a transceiver and a mobile station in order to allocate a channel to the mobile station will be described. 
         [0076]      FIG. 6  is a diagram illustrating a method for updating connection information according to an embodiment of the present invention. 
         [0077]    As shown in  FIG. 6 , first, the controller  230  of the base station system  200  configures an OFDMA frame inserted with a transceiver identification symbol (S 201 ). 
         [0078]    At this time, the OFDMA frame is constituted by a plurality of OFDM symbols, and includes a downlink frame section where a signal is transmitted from the base station system  200  to the mobile station and an uplink frame section where the signal is transmitted from the mobile station to the base station system  200 . The downlink frame section includes a transceiver identification symbol section including a plurality of transceiver identification symbols. 
         [0079]    Next, the controller  230  of the base station system  200  allocates an uplink channel to the first mobile station  11  in accordance with the connection information between the transceiver and the mobile station, which is stored in the connection information table  210  (S 203 ). At this time, the controller  230  may allocate the uplink channel for the first mobile station  11  so that the first mobile station  11  communicates with the optimal transceiver for the first mobile station  11  in accordance with the connection information between the transceiver and the mobile station. 
         [0080]    Thereafter, the controller  230  of the base station system  200  generates a plurality of communication frames corresponding to the plurality of transceivers  250 , respectively, on the basis of the predetermined combination of the subcarriers for the transceivers (S 205 ). 
         [0081]    At this time, the controller  230  may generate a first communication frame including a symbol corresponding to a subcarrier allocated to a first transceiver  251  among the plurality of transceiver identification symbols, may generate a second communication frame including a symbol corresponding to a subcarrier allocated to a second transceiver  252  among the plurality of transceiver identification symbols, may generate a third communication frame including a symbol corresponding to a subcarrier allocated to a third transceiver  253  among the plurality of transceiver identification symbols, and may generate a fourth communication frame including a symbol corresponding to a subcarrier allocated to a fourth transceiver  254  among the plurality of transceiver identification symbols. 
         [0082]    Next, the base station system  200  transmits the plurality of communication frames to the first mobile station  11  through the plurality of transceivers  250  (S 207 ). 
         [0083]    At this time, the first transceiver  251  may transmit the first communication frame through the subcarrier allocated to the first transceiver  251 , the second transceiver  252  may transmit the second communication frame through the subcarrier allocated to the second transceiver  252 , the third transceiver  253  may transmit the third communication frame through the subcarrier allocated to the third transceiver  253 , and the fourth transceiver  254  may transmit the fourth communication frame through the subcarrier allocated to the fourth transceiver  254 . 
         [0084]    Thereafter, the first mobile station  11  calculates quality of a received signal between each transceiver and the first mobile station  11  on the basis of the plurality of received communication frames (S 209 ). At this time, the first mobile station  11  may calculate the quality of the received signal between each transceiver and the first mobile station  11  in accordance with Equation 1. 
         [0085]    Next, if a transceiver having quality of the received signal that is better than the optimal transceiver of the first mobile station  11  is provided on the basis of the calculated quality of the received signal, the first mobile station  11  transmits the signal quality information on the first mobile station  11 , which includes the quality of the received signal between each transceiver and the first mobile station  11 , to the base station system  200  (S 211 ). At this time, the first mobile station  11  may transmit the signal quality information to the base station system  200  through the allocated uplink channel. 
         [0086]    Thereafter, the controller  230  of the base station system  200  changes the optimal transceiver for the first mobile station  11  on the basis of the received signal quality information on the first mobile station  11  (S 213 ). 
         [0087]    Next, the controller  230  of the base station system  200  updates the connection information between the transceiver and the mobile station on the basis of the changed optimal transceiver for the first mobile station  11 . (S 215 ). At this time, the controller  230  may update the connection information between the transceiver and the mobile station, which is stored in the connection information table  210 , on the basis of the changed optimal transceiver of the first mobile station  11 . 
         [0088]    As such, when the optimal transceiver of the mobile station is changed, the base station system  200  can communicate with the optimal transceiver at the changed location by reflecting the changed matters to the connection information even though the location of the mobile station is changed through movement of the mobile station. 
         [0089]    Next, referring to  FIG. 7 , an electronic toll collection (hereinafter also referred to as “ETC”) system according to an embodiment of the present invention will be described. 
         [0090]      FIG. 7  is a diagram illustrating a configuration of an electronic toll collection system according to an embodiment of the present invention. 
         [0091]    As shown in  FIG. 7 , the ETC system  400 , as a system providing a service to allow a vehicle to arbitrarily change a traffic lane in a section where a toll is charged, includes a base station processing device  410 , four transceivers, i.e., a first transceiver  431 , a second transceiver  432 , a third transceiver  433 , a fourth transceiver  434 , and a vehicle entry sensor  450 . 
         [0092]    The base station processing device  410  corresponds to a device for performing functions of the connection information table  210  and the controller  230  of the base station system  200  according to a first embodiment of the present invention, which is shown in  FIG. 2 . 
         [0093]    The first transceiver  431  forms a first communication area  431   a  in a first traffic lane and operates in the first communication area  431   a . At this time, the first transceiver  431  communicates with a mobile station positioned in the first communication area  431   a  through the first uplink channel determined by the combination of the subcarriers allocated to the first transceiver  431 , that is, the combination of the first subcarriers. 
         [0094]    The second transceiver  432  forms a second communication area  432   a  in a second traffic lane and operates in the second communication area  432   a . At this time, the second transceiver  432  communicates with a mobile station positioned in the second communication area  432   a  through the second uplink channel determined by the combination of the subcarriers allocated to the second transceiver  432 , that is, the combination of the second subcarriers. 
         [0095]    The third transceiver  433  forms a third communication area  433   a  in a third traffic lane and operates in the third communication area  433   a . At this time, the third transceiver  433  communicates with a mobile station positioned in the third communication area  433   a  through the third uplink channel determined by the combination of the subcarriers allocated to the third transceiver  433 , that is, the combination of the third subcarriers. 
         [0096]    The fourth transceiver  434  forms a fourth communication area  434   a  in a fourth traffic lane and operates in the fourth communication area  434   a . At this time, the fourth transceiver  434  communicates with a mobile station positioned in the fourth communication area  434   a  through the fourth uplink channel determined by the combination of the subcarriers allocated to the fourth transceiver  434 , that is, the combination of the fourth subcarriers. 
         [0097]    The vehicle entry sensor  450  separates a violation vehicle from logical terminal existence information by communication in a corresponding area by collecting a vehicle number plate image through a camera at the time of vehicle&#39;s entering for identification a charging violation vehicle. 
         [0098]    When a vehicle  21  corresponding to the mobile station is positioned at the first communication area  431   a , the vehicle  21  communicates with the first transceiver  431  through the first uplink channel. 
         [0099]    When the vehicle  21  moves from the first communication area  431   a  to the second communication area  432   a , the vehicle  21  communicates with the second transceiver  432  through the second uplink channel. 
         [0100]    At this time, since the signal reception quality of the transceiver identification symbol corresponding to the combination of the second subcarriers is the best, the vehicle  21  transmits the reception quality information including the signal reception quality between each transceiver and the vehicle  21  to the second transceiver  432 . 
         [0101]    Thereafter, the base station processing device  410  recognizes that the vehicle  21  enters the second communication area  432   a  by the received reception quality information, and the vehicle  21  may perform the communication through the second transceiver  432 . 
         [0102]    Next, referring to  FIG. 8 , a single frequency network (hereinafter also referred to as “SFN”) at the roadside using a base station system according to an embodiment of the present invention will be described. 
         [0103]      FIG. 8  is a diagram illustrating a configuration of a single frequency network at the roadside according to an exemplary embodiment of the present invention. 
         [0104]    As shown in  FIG. 8 , the single frequency network at the roadside includes a plurality of base station systems, i.e., a first base station system  500  and a second base station system  600 . 
         [0105]    The first base station system  500  includes a first base station processing device  510  and fourth transceivers, i.e., a first transceiver  531 , a second transceiver  532 , a third transceiver  533 , and a fourth transceiver  534 . 
         [0106]    The second base station system  600  includes a second base station processing device  610  and four transceivers, i.e., a fifth transceiver  631 , a sixth transceiver  632 , a seventh transceiver  633 , and an eighth transceiver  634 . 
         [0107]    The first base station processing device  510  and the second base station processing device  610  correspond to a device for performing the functions of the connection information table  210  and the controller  230  of the base station system  200  according to the first embodiment of the present invention, which is shown in  FIG. 2 . 
         [0108]    The first transceiver  531  forms a first communication area  531   a . The second transceiver  532  forms a second communication area  532   a . The third transceiver  533  forms a third communication area  533   a . The fourth transceiver  534  forms a fourth communication area  534   a . The fifth transceiver  631  forms a fifth communication area  631   a . The sixth transceiver  632  forms a sixth communication area  632   a . The seventh transceiver  633  forms a seventh communication area  633   a . The eighth transceiver  634  forms an eighth communication area  634   a . The communication area of each transceiver partially overlaps with a communication area of an adjacent transceiver. 
         [0109]    If a first vehicle  31  corresponding to the mobile station is positioned at a location where the second communication area  532   a  overlaps with the third communication area  533   a , the first base station processing device  510  can know a moving situation of the first vehicle  31  in accordance with the signal quality information on the first vehicle  31  and the resource can be allocated to the first vehicle  31  through the third transceiver  533 . 
         [0110]    If a second vehicle  32  corresponding to the mobile station is positioned at a location where the fourth communication area  534   a  overlaps with the fifth communication area  631   a , the first base station processing device  510  prevents a communication service that is in progress from being cut when the second vehicle  32  enters the fifth communication area  631   a  by sharing information on a service state of the second vehicle  32  with the second base station processing device  610 . At this time, the fourth transceiver  534  and the fifth transceiver  631  can evade mutual interference by using different subcarriers. 
         [0111]    According to an embodiment of the present invention, it is possible to provide different communication services depending on the location of a terminal or a mobile station that exists in a communication area of a base station with one frequency channel by using an orthogonal frequency division multiple access (OFDMA) method. Further, it is possible to provide a location-based communication service without an additional location recognition module. 
         [0112]    The above-mentioned exemplary embodiments of the present invention are not embodied only by an apparatus and method. Alternatively, the above-mentioned exemplary embodiments may be embodied by a program performing functions that correspond to the configuration of the exemplary embodiments of the present invention, or a recording medium on which the program is recorded. These embodiments can be easily devised from the description of the above-mentioned exemplary embodiments by those skilled in the art to which the present invention pertains. 
         [0113]    While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Technology Classification (CPC): 7