Abstract:
Provided is a data transmission system of providing preambles of different classes according to a characteristic of a terminal. A terminal having constraints on using a power with respect to a data reception may receive only a preamble of a particular class and thus decrease a power consumption. A generally terminal may receive preambles of plural classes and quickly receive data.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit under 35 U.S.C. §119(a) of a Korean Patent Application No. 10-2010-0029983, filed on Apr. 1, 2010, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    The following description relates to a mobile communication field, and more particularly, to a preamble structure of transmitting preambles of different classes. 
         [0004]    2. Description of Related Art 
         [0005]    A reception apparatus may receive data from a transmission apparatus. In general, the reception apparatus may be unaware when the transmission apparatus transmits data. When the reception apparatus waits for data to be transmitted from the transmission apparatus at all times, the reception apparatus may use a significantly great amount of power to receive the data. Accordingly, in an idle state, the reception apparatus may periodically monitor whether the transmission apparatus transmits data. Only when the transmission apparatus transmits the data, the reception apparatus may shift from the idle state to an active state and receive the data. 
         [0006]    For the above operation, the transmission apparatus may include a preamble within a frame to transmit data. In the idle status, the reception apparatus may periodically attempt a detection of the preamble transmitted from the transmission apparatus. When the reception apparatus succeeds in the detection of the preamble, the reception apparatus determines data is to be transmitted from the transmission apparatus, and thus may shift from the idle state to the active state and receive the data. 
       SUMMARY 
       [0007]    In one general aspect, a transmission apparatus includes a first preamble transmitter to transmit a first preamble and first data to a first reception apparatus, and a second preamble transmitter to transmit a second preamble and second data to the first reception apparatus and a second reception apparatus. The first data may be received depending on whether the first preamble is detected, and the second data is received depending on whether the second preamble is detected. 
         [0008]    In another general aspect, a reception apparatus includes a receiver to receive, from a transmission apparatus, a signal containing a first preamble or a second preamble, a control signal receiver to receive a control signal, a first preamble detector to detect the first preamble, and a second preamble detector to detect the second preamble. The control signal receiver may activate the first preamble detector or the second preamble detector according to the control signal. When the first preamble or the second preamble is detected, the receiver may receive data from the transmission apparatus. 
         [0009]    In still general aspect, a reception apparatus includes a preamble detector to detect a first preamble or a second preamble received from a transmission apparatus, and a receiver to receive data from the transmission apparatus depending on whether the first preamble or the second preamble is detected. A second reception apparatus may detect the second preamble received from the transmission apparatus, and may receive second data from the transmission apparatus depending on whether the second preamble is detected. 
         [0010]    In yet another general aspect, a reception apparatus includes a detector to detect a first preamble received from a transmission apparatus, and a receiver to receive data from the transmission apparatus depending on whether the first preamble is detected. A second reception apparatus may detect the first preamble or a second preamble received from the transmission, and may receive second data from the transmission apparatus depending on whether the second preamble is detected. 
         [0011]    According to embodiments, it is possible to decrease a power consumption of a reception apparatus in an idle state. 
         [0012]    According to embodiments, it is possible to increase a standby time of a reception apparatus. 
         [0013]    Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a diagram to describe an example of a method of transmitting and receiving data using a multi-class preamble structure. 
           [0015]      FIG. 2  is a diagram illustrating an example of multiple preambles. 
           [0016]      FIG. 3  is a diagram illustrating an example of each reception apparatus receiving a first preamble. 
           [0017]      FIG. 4  is a diagram illustrating an example of each reception apparatus receiving a second preamble. 
           [0018]      FIG. 5  is a diagram illustrating an example of a transmission apparatus. 
           [0019]      FIG. 6  is a diagram illustrating an example of a reception apparatus. 
           [0020]      FIG. 7  is a diagram illustrating another example of a reception apparatus. 
           [0021]      FIG. 8  is a diagram illustrating still another example of a reception apparatus. 
           [0022]      FIG. 9  is a diagram illustrating an example of a data transmission method. 
           [0023]      FIG. 10  is a diagram illustrating an example of a data reception method. 
           [0024]      FIG. 11  is a diagram illustrating another example of a data reception method. 
       
    
    
       [0025]    Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals will be understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience. 
       DETAILED DESCRIPTION 
       [0026]    The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be suggested to those of ordinary skill in the art. The progression of processing steps and/or operations described is an example; however, the sequence of and/or operations is not limited to that set forth herein and may be changed as is known in the art, with the exception of steps and/or operations necessarily occurring in a certain order. Also, description of well-known functions and constructions may be omitted for increased clarity and conciseness. 
         [0027]      FIG. 1  illustrates a diagram to describe an example of a method of transmitting and receiving data using a multi-class preamble structure. 
         [0028]    According to an embodiment, a transmission apparatus may transmit, to a reception apparatus, a data frame containing data. In an idle state, the reception apparatus may detect a preamble included in the data frame. When the reception apparatus succeeds in a detection of the preamble, the reception apparatus may determine data is being transmitted from the transmission apparatus. When the data is not being transmitted from the transmission apparatus, the reception apparatus may maintain the idle state and decrease a power communication. Conversely, when the data is transmitted from the transmission apparatus, the reception apparatus may shift from the idle state to an active state to receive the data. 
         [0029]    The transmission apparatus may transmit data to a plurality of reception apparatus having different characteristics. For example, a first reception apparatus may be stably supplied with a power from a power socket and the like. The first reception apparatus may receive data without a limitation on the power. A second reception apparatus may be supplied with the power using a battery and the like. The second reception apparatus may have some constraints on receiving the data due to a limitation of the power. 
         [0030]    The transmission apparatus may transmit different preambles designed based on characteristics of the respective reception apparatuses. Each of the reception apparatuses may detect a portion of or all of the preambles based on corresponding characteristics. For example, the first reception apparatus may detect both a first preamble and a second preamble. Specifically, the first reception apparatus, which is not affected by the power limitation, may detect all the preambles, and quickly receive data from the transmission apparatus. The second reception apparatus being affected by the power limitation may detect only the second preamble and effectively receive data. 
         [0031]    Referring to  FIG. 1 , a transmission apparatus transmits, to a second reception apparatus, data frames  111  and  121  containing first preambles  110  and  120 , and a data frame  131  containing a second preamble  131 . In this instance, the second reception apparatus does not detect the first preambles  110  and  120  and thus may not receive data included in the data frames  111  and  121  containing the first preambles  110  and  120 . The second reception apparatus detects the second preamble  130  and thus may receive data  140  included in the data frame  131  containing the second preamble  130 . 
         [0032]    According to another embodiment, a first reception apparatus may detect only a first preamble and may receive data from a transmission apparatus. A second reception apparatus may detect only a second preamble and receive data from the transmission apparatus. 
         [0033]      FIG. 2  illustrates an example of multiple preambles. 
         [0034]    Referring to  FIG. 2 , a first preamble may be repeatedly transmitted during every first time interval  220 . A second preamble may be repeatedly transmitted during every second time interval  231  or  232 . A transmission apparatus may transmit all of the first preamble and the second preamble. Each of reception apparatuses may receive a preamble corresponding to a characteristic of a corresponding reception apparatus. 
         [0035]    A length of the first time interval  220  may be different from a length of the second time interval  231  or  232 . As shown in  FIG. 2 , the first time interval  220  may be an integer multiple of the second time interval  231  or  232 . 
         [0036]    A first reception apparatus may receive preambles repeated during every first time interval  220 . Referring to  FIG. 2 , the first reception apparatus may receive the first preamble and the second preamble repeated during every first time interval  220 . 
         [0037]    A second reception apparatus may receive preambles repeated during every second time interval  231  or  232 . Referring to  FIG. 2 , the second reception apparatus may receive the second preamble repeated during every second time interval  231  or  232 . However, the second reception apparatus may not receive the first preamble. 
         [0038]      FIG. 3  illustrates an example of each reception apparatus receiving a first preamble. 
         [0039]    A first reception apparatus may detect the first preamble by correlating a first correlation signal with a signal received from a transmission apparatus. A length of the first correlation signal may be the same as a length of a first time interval. Specifically, when the length of the first correlation signal is the same as a length of the first preamble, the first reception apparatus may detect preambles repeated during every first time interval. 
         [0040]    Referring to  FIG. 3 , the first reception apparatus may detect the first preamble after the first preamble is repeated twice. 
         [0041]    A second reception apparatus may detect a second preamble by correlating a second correlation signal with the signal received from the transmission apparatus. A length of the second correlation signal may be the same as a length of a second time interval. Specifically, when the length of the second correlation signal is the same as a length of the second preamble, the second reception apparatus may detect preambles repeated during every second time interval. 
         [0042]    However, when the length of the first preamble is an integer multiple of the length of the second correlation signal, the second reception apparatus may not detect the first preamble. Referring to  FIG. 3 , the second reception apparatus may not detect the first preamble. 
         [0043]      FIG. 4  illustrates an example of each reception apparatus receiving a second preamble. 
         [0044]    The second preamble is repeated during every second time interval. A length of a first time interval is an integer multiple of a length of the second time interval. Accordingly, when an integer number of second preambles are combined, the second preamble may be repeated during every first time interval. Accordingly, in  FIG. 4 , a first reception apparatus may detect the second preamble after the first time interval is repeated twice, using a first correlation signal. 
         [0045]    A second reception apparatus may detect the second preamble after the second time interval is repeated twice. 
         [0046]      FIGS. 3 and 4  illustrate examples in which each reception apparatus may receive the preambles of  FIG. 2 . The first reception apparatus may receive both the first preamble and the second preamble. The second reception apparatus may receive only the second preamble. 
         [0047]      FIG. 5  illustrates an example of a transmission apparatus  500 . 
         [0048]    The transmission apparatus  500  includes a first preamble transmitter  510 , a control signal transmitter  520 , and a second preamble transmitter  530 . 
         [0049]    The first preamble transmitter  510  may transmit, to a first reception apparatus  540 , a first preamble detectable by the first reception apparatus  540 . 
         [0050]    The second preamble transmitter  530  may transmit, to a second reception apparatus  550 , a second preamble detectable by the second reception apparatus  550 . 
         [0051]    The first preamble transmitter  510  may transmit the first preamble to the second reception apparatus  550 , and the second preamble transmitter  530  may transmit the second preamble to the first reception apparatus  540 . In this case, even though the second reception apparatus  550  may not detect the first preamble, the first reception apparatus  540  may detect the second preamble. 
         [0052]    A length of the first preamble may be an integer multiple of the second preamble. 
         [0053]    The first reception apparatus  540  may denote a reception apparatus that may be stably supplied with a power from a power socket, and the like. The second reception apparatus  550  may denote a reception apparatus that may be supplied with the power using a battery and the like. In this case, the first reception apparatus  540  may receive data without a limitation on the power, and the second reception apparatus  550  may have some constraints on receiving the data due to a limitation of the power. 
         [0054]    As described above, the first reception apparatus  540  may detect both the first preamble and the second preamble. When the first reception apparatus  540  receives data, the power may be unlimited and thus the first reception apparatus  540  may attempt a detection of the first preamble or the second preamble during every time interval where the first preamble or the second preamble is transmitted. When the first reception apparatus  540  succeeds in a preamble detection, the first reception apparatus  540  may determine data is to be transmitted from the transmission apparatus  500 . Accordingly, the first reception apparatus  540  may shift from an idle state to an active state, and may receive data from the transmission apparatus  500 . 
         [0055]    The second reception apparatus  550  may detect only the second preamble. The second reception apparatus  550  may attempt a detection of the second preamble during every time interval where the second preamble is transmitted. The second reception apparatus  550  may attempt the detection of only the second preamble, and thus may decrease a power consumption compared to the first reception apparatus  540 . When the second reception apparatus  550  succeeds in the detection of the second preamble, the second reception apparatus  550  may determine data is to be transmitted from the transmission apparatus  500 . Accordingly, the second reception apparatus  550  may shift from the idle state to the active state and receive data from the transmission apparatus  500 . 
         [0056]    The control signal transmitter  520  may transmit a control signal to each of the first reception apparatus  540  and the second reception apparatus  550 . Each of the first reception apparatus  540  and the second reception apparatus  550  may detect both the first preamble and the second preamble, or may detect only the first preamble according to the control signal. 
         [0057]      FIG. 6  illustrates an example of a reception apparatus  600 . 
         [0058]    The reception apparatus  600  includes a receiver  610 , a control signal receiver  620 , a first preamble detector  630 , and a second preamble detector  640 . 
         [0059]    The receiver  610  may receive, from a transmission apparatus  650 , a signal containing a first preamble or a second preamble. 
         [0060]    The control signal receiver  620  may receive a control signal from an upper layer. The control signal may include information associated with a preamble to be detected by the reception apparatus  600 . 
         [0061]    The first preamble detector  630  may detect the first preamble. 
         [0062]    The second preamble detector  640  may detect the second preamble. 
         [0063]    When the reception apparatus  600  is in an idle state, the control signal receiver  620  may decrease a power consumption of the reception apparatus  600  by inactivating the first preamble detector  630  and the second preamble detector  640 , and by cutting off the power. 
         [0064]    The transmission apparatus  650  may designate a preamble to be received by the reception apparatus  600 , using the control signal. The transmission apparatus  650  may transmit the control signal to the reception apparatus  600 . The upper layer of the reception apparatus  600  may recognize the control signal. The control signal receiver  620  may receive the control signal from the upper layer. 
         [0065]    The control signal receiver  620  may activate the first preamble detector  630  or the second preamble detector  640  according to the control signal. For example, when the control signal indicates that “the reception apparatus  600  needs to detect the first preamble”, the control signal receiver  620  may activate the first preamble detector  630  during a time interval where the first preamble is transmitted. Since the second preamble detector  640  is not activated and only the first preamble detector  630  is activated, a power consumption of the reception apparatus  600  may decrease. 
         [0066]    When the control signal indicates that “the reception apparatus  600  needs to detect the second preamble”, the control signal receiver  620  may decrease the power consumption by activating only the second preamble detector  640 . 
         [0067]    A length of the first preamble may be an integer multiple of a length of the second preamble. In this case, the first preamble detector  630  may detect the first preamble as well as the second preamble. 
         [0068]      FIG. 7  illustrates another example of a reception apparatus  700 . 
         [0069]    The reception apparatus  700  includes a receiver  710 , a first preamble detector  720 , a second preamble detector  730 , and a multiplexer (MUX)  740 . 
         [0070]    The receiver  710  may receive, from a transmission apparatus  750 , a signal containing a first preamble or a second preamble. 
         [0071]    The first preamble detector  720  may detect the first preamble included in the received signal. When the first preamble is included in the received signal, the first preamble detector  720  may succeed in a detection of the first preamble. 
         [0072]    The second preamble detector  730  may detect the second preamble included in the received signal. When the second preamble is included in the received signal, the second preamble detector  730  may succeed in a detection of the second preamble. 
         [0073]    The MUX  740  may select one of an output of the first preamble detector  720  and an output of the second preamble detector  730  according to the control signal. 
         [0074]    For example, the received signal may include the first preamble and the first preamble detector  720  may detect the first preamble. In this case, the MUX  740  may select the output of the first preamble detector  720  according to the control signal. 
         [0075]    The received signal may include the second preamble and the second preamble detector  730  may detect the second preamble. In this case, the MUX  740  may select the output of the second preamble detector  730 . 
         [0076]      FIG. 8  illustrates still another example of a reception apparatus  800 . The reception apparatus  800  includes a preamble detector  810  and a receiver  820 . 
         [0077]    The reception apparatus  800  may operate to detect both a first preamble and a second preamble, or may operate to detect only the second preamble. 
         [0078]    1) When the Reception Apparatus  800  Operates to Detect Both the First Preamble and the Second Preamble: 
         [0079]    The preamble detector  810  may detect the first preamble or the second preamble received from a transmission apparatus  830 . The second preamble may be a preamble detectable by both the reception apparatus  800  and a second reception apparatus  840 , and the first preamble may be a preamble detectable by only the reception apparatus  800 . 
         [0080]    A length of the first preamble may be an integer multiple of a length of the second preamble. In this case, the transmission apparatus  830  may repeatedly transmit the second preamble during a time interval where the first preamble is transmitted. 
         [0081]    The receiver  820  may receive data from the transmission apparatus  830  depending on whether the first preamble or the second preamble is detected. When the preamble detector  810  succeeds in a detection of the first preamble or the second preamble, the receiver  820  may receive data from the transmission apparatus  830 . 
         [0082]    The second reception apparatus  840  may detect the first preamble received from the transmission apparatus  830 . When the second reception apparatus  840  succeeds in the detection of the first preamble, the second reception apparatus  840  may receive second data from the transmission apparatus  830 . 
         [0083]    2) When the Reception Apparatus  800  Operates to Detect Only the First Preamble: 
         [0084]    The preamble detector  810  may detect the second preamble received from the transmission apparatus  830 . The second preamble may be a preamble detectable by both the reception apparatus  800  and the second reception apparatus  840 , and the first preamble may be a preamble detectable by only the reception apparatus  800 . 
         [0085]    A length of the first preamble may be an integer multiple of a length of the second preamble. In this case, the transmission apparatus  830  may repeatedly transmit the second preamble during a time interval where the first preamble is transmitted. 
         [0086]    The receiver  820  may receive data from the transmission apparatus  830  depending on whether the first preamble is detected. When the preamble detector  810  succeeds in a detection of the first preamble, the receiver  820  may receive data from the transmission apparatus  830 . 
         [0087]    The second reception apparatus  840  may detect the first preamble or the second preamble received from the transmission apparatus  830 . When the second reception apparatus  840  succeeds in the detection of the first preamble or the second preamble, the second reception apparatus  840  may receive second data from the transmission apparatus  830 . 
         [0088]      FIG. 9  illustrates an example of a data transmission method. 
         [0089]    In operation  910 , a transmission apparatus transmits a first preamble and first data to a first reception apparatus. 
         [0090]    In operation  920 , the transmission apparatus transmits a second preamble and second data to the first reception apparatus and a second reception apparatus. 
         [0091]    The second preamble may be a preamble detectable by both the first reception apparatus and the second reception apparatus, and the first preamble may be a preamble detectable only by the first reception apparatus. A length of the first preamble may be an integer multiple of a length of the second preamble. 
         [0092]    The transmission apparatus may repeatedly transmit the second preamble during a time interval where the first preamble is transmitted. 
         [0093]    The first reception apparatus may detect both the first preamble and the second preamble. When the first reception apparatus succeeds in a detection of the first preamble, the first preamble apparatus may receive the first data. When the first reception apparatus succeeds in a detection of the second preamble, the first reception apparatus may receive the second data. 
         [0094]    The second reception apparatus may detect the second preamble. When the second reception apparatus succeeds in the detection of the second preamble, the second reception apparatus may receive the second data. 
         [0095]    The first reception apparatus may denote a reception apparatus that may be stably supplied with a power from a power socket, and the like. The second reception apparatus may denote a reception apparatus that may be supplied with the power using a battery and the like. In this case, the first reception apparatus may receive data without a limitation on the power, and the second reception apparatus may have some constraints on receiving the data due to a limitation of the power. 
         [0096]    The second reception apparatus may operate only during a time interval where the second preamble is transmitted, and thus may decrease a power consumption in receiving data. 
         [0097]      FIG. 10  illustrates an example of a data reception method. 
         [0098]    In operation  1010 , a reception apparatus receives, from a transmission apparatus, a signal containing a first preamble or a second preamble. 
         [0099]    The first preamble may be a preamble detectable by only the first reception apparatus, and the second preamble may be a preamble detectable by the first reception apparatus and the second reception apparatus. A length of the first preamble may be an integer multiple of a length of the second preamble. The transmission apparatus may repeatedly transmit the second preamble during a time interval where the first preamble is transmitted. 
         [0100]    In operation  1020 , the reception apparatus receives a control signal from the transmission apparatus. The control signal may include information associated with a preamble to be received by the reception apparatus. 
         [0101]    In operation  1030 , the reception apparatus detects the first preamble or the second preamble according to the control signal. 
         [0102]    The control signal may include information associated with one of the first preamble and the second preamble, and the reception apparatus may detect only one of the first preamble and the second preamble according to the control signal. The reception apparatus may include a first preamble detector to detect the first preamble and a second preamble detector to detect the second preamble. The reception apparatus may decrease a power consumption by inactivating one of the first preamble detector and the second preamble detector according to the control signal. 
         [0103]    In operation  1040 , the reception apparatus receives data from the transmission apparatus depending on whether the first preamble or the second preamble is detected. 
         [0104]      FIG. 11  illustrates another example of a data reception method. 
         [0105]    In operation  1110 , a reception apparatus detects a first preamble or a second preamble received from a transmission apparatus. 
         [0106]    The second preamble may be a preamble detectable by both the reception apparatus and a second reception apparatus, and the first preamble may be a preamble detectable by only the reception apparatus. 
         [0107]    A length of the first preamble may be an integer multiple of a length of the second preamble. The transmission apparatus may repeatedly transmit the second preamble during a time interval where the first preamble is transmitted. 
         [0108]    In operation  1110 , the second reception apparatus may detect the second preamble. 
         [0109]    In operation  1120 , the reception apparatus receives data from the transmission apparatus depending on whether the first preamble or the second preamble is detected. When the reception apparatus succeeds in a detection of the first preamble or when the reception apparatus succeeds in a detection of the second preamble, the reception apparatus may receive data from the transmission apparatus. 
         [0110]    When the second reception apparatus succeeds in the detection of the second preamble, the second reception apparatus may receive data from the transmission apparatus. 
         [0111]    The second reception apparatus may operate to detect the second preamble only during a time interval where the second preamble is transmitted, and may not operate during a time interval where the first preamble is transmitted. Accordingly, when receiving data, it is possible to decrease a power consumption with respect to a data reception. 
         [0112]    The methods described above may be recorded, stored, or fixed in one or more non-transitory computer-readable media that includes program instructions to be implemented by a computer to cause a processor to execute or perform the program instructions. The media may also include, alone or in combination with the program instructions, data files, data structures, and the like. The media and program instructions may be those specially designed and constructed, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of non-transitory computer-readable media include magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD-ROM disks and DVDs; magneto-optical media such as optical disks; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory (ROM), random access memory (RAM), flash memory, and the like. Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher level code that may be executed by the computer using an interpreter. The described hardware devices may be configured to act as one or more software modules in order to perform the operations and methods described above, or vice versa. 
         [0113]    A number of examples have been described above. Nevertheless, it should be understood that various modifications may be made. For example, suitable results may be achieved if the described techniques are performed in a different order and/or if components in a described system, architecture, device, or circuit are combined in a different manner and/or replaced or supplemented by other components or their equivalents. Accordingly, other implementations are within the scope of the following claims.