Abstract:
Provided is a technology related to a sensor network, machine to machine (M2M), machine type communication (MTC), and the Internet of things (IoT). Transmitting data between transceivers including transmitting data segments of source data and parity data segments including restoration information for a transceiver to restore the source data. The method is applicable to intelligent services based on the technology (e.g., smart home services, smart building services, smart city services, smart or connected car services, health care services, digital education services, retail business services, security and safety-related services, etc.).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/043,607, filed on Aug. 29, 2014, in the US Patent Office, and claims the benefit of Korean Patent Application No. 10-2015-0063225, filed on May 6, 2015, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entireties. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    Methods and apparatuses consistent with exemplary embodiments relate to a method of transmitting and receiving data by using a first transceiver and a second transceiver, and a recording medium having recorded thereon a program for executing a method of transmitting and receiving data. 
         [0004]    2. Description of the Related Art 
         [0005]    The Internet has evolved from a human-centered network via which humans create and consume information to the Internet of Things (IoT) via which information is exchanged and processed among distributed components such as objects. Thus, much attention has been paid to the Internet of Everything (IoE) technology that is a combination of a technology of processing big data by accessing a cloud server and IoT technology. For the IoT, technologies, such as sensing technology, a wire/wireless communication and network infrastructure, service interface technology, and security technology are required. Therefore, research has recently been conducted on technologies for connecting objects, such as a sensor network, machine-to-machine (M2M), machine type communication (MTC), etc. 
         [0006]    In an IoT environment, data generated by objects connected to each other may be collected and analyzed to provide an intelligent Internet technology service for creating a new value for human life. Through the IoT, the existing information technologies may be fused or combined with various industrial technologies, and applied to the fields of smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart home appliances, advanced medical services, etc. 
       SUMMARY 
       [0007]    Aspects of the exemplary embodiments relate to methods and apparatuses for exchanging data between a first transceiver and a second transceiver by providing control information for obtaining the data from the second transceiver to the first transceiver, thereby more efficiently using resources required to transmit and receive the data based on the control information. 
         [0008]    Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented exemplary embodiments. 
         [0009]    According to an aspect of an exemplary embodiment, a method of transmitting data, performed by a first transceiver, includes transmitting data segments of source data and parity data segments comprising restoration information for restoring the source data, to a second transceiver; receiving from the second transceiver a control signal representing whether the source data is obtained by the second transceiver, based on at least one data segment among the source data segments and the parity data segments; determining that additional data segments for the second transceiver to obtain the source data are to be transmitted, based on the control signal; and transmitting the additional data segments to the second receiver. 
         [0010]    According to an exemplary embodiment, a point of time at which a parity data set including a plurality of parity data segments is to be transmitted may be determined to be a point of time after a data round-trip time between the first transceiver and the second transceiver, starting from a point of time at which the transmitting of the source data is completed. 
         [0011]    According to an exemplary embodiment, a control signal may include information representing whether the source data is obtained, and the receiving of the control signal may include receiving, from the second transceiver, a request to provide the additional data segments for obtaining the source data. The method may further include transmitting the additional data segments according to the received request. 
         [0012]    According to an exemplary embodiment, the receiving of the control signal may include receiving, from the second transceiver, information regarding a quantity of the additional data segments for obtaining the source data. The method may further include transmitting the additional data segments, based on the information regarding the quantity of the additional data segments. 
         [0013]    According to an exemplary embodiment, the method may further include receiving information indicating a data loss section predicted by the second transceiver based on the at least one data segment, from the second transceiver; and changing a transmission section in which the additional data segments are transmitted, based on the information indicating the predicted data loss section. 
         [0014]    According to an exemplary embodiment, when it is determined based on the control signal that the source data is obtained by the second transceiver, the method may further include discontinuing the transmitting of the additional data segments. 
         [0015]    According to an aspect of another exemplary embodiment, a method of transmitting and receiving data, performed by a receiving transceiver, includes receiving at least one data segment among data segments of source data and parity data segments including restoration information for restoring the source data, from a transmitting transceiver; determining that the source data is not obtained by the transmitting transceiver, based on the received at least one data segment; and transmitting a control signal indicating that the source data is not obtained, to the transmitting transceiver, based on a result of the determining. 
         [0016]    The method may further include identifying the received at least one data segment; predicting a quantity of parity data segments to be received after the identified at least one data segment; and comparing the predicted quantity of the parity data segments and a quantity of the received at least one data segment with a quantity of data segments required to obtain the source data. The transmitting of the control signal may include requesting additional data segments for obtaining the source data, based on a result of the comparing, to the transmitting transceiver. 
         [0017]    According to an exemplary embodiment, the requesting of the additional data segments may include obtaining information indicating the quantity of the additional data segments required to obtain the source data. 
         [0018]    According to an exemplary embodiment, the method may further include predicting a point of time at which the parity data segments are to be received, based on identification information of the received at least one data segment and a point of time at which the received at least one data segment is received. When the parity data segments are not received at the predicted point of time, the transmitting of the control signal may include requesting additional data segments for obtaining the source data. 
         [0019]    According to an exemplary embodiment, the method may further include predicting a data loss section, based on information regarding a point of time at which the received at least one data segment is received; and transmitting information regarding the predicted data loss section to the first transceiver. A transmission section in which additional data segments for obtaining the source data are transmitted may be determined based on the information regarding the predicted data loss section. 
         [0020]    According to an aspect of another exemplary embodiment, a first transceiver for transmitting and receiving data includes a transmission unit configured to transmit source data segments included in source data and parity data segments comprising restoration information for restoring the source data, to a second transceiver; a receiving unit configured to receive from the second transceiver a control signal representing whether the source data is obtained, based on at least one data segment among the source data segments and the parity data segments; and a data transmission controller configured to determine that additional data segments for the second transceiver to obtain the source data are to be transmitted, based on the control signal and control the transmission unit to transmit the additional data segments to the second receiver. 
         [0021]    According to an exemplary embodiment, a point of time at which a parity data set including a plurality of parity data segments is to be transmitted may be determined after a data round-trip time between the first transceiver and the second transceiver, starting from a point of time at which the transmission of the source data is completed. 
         [0022]    According to an exemplary embodiment, the control signal may include information representing whether the second transceiver obtains the source data, the receiving unit may receive a request to provide the additional data segments for obtaining the source data from the second transceiver, and the transmission unit may transmit the additional data segments according to the request. 
         [0023]    According to an exemplary embodiment, the receiving unit may receive information regarding a quantity of the additional data segments for the second transceiver to obtain the source data, from the second transceiver, and the transmission unit may transmit the additional data segments, based on the information regarding the quantity of the additional data segments. 
         [0024]    According to an exemplary embodiment, the receiving unit may receive information indicating a data loss section predicted based on the at least one data segment from the second transceiver, and the data transmission controller may change a transmission section in which the additional data segments are transmitted, based on the information regarding the predicted data loss section. 
         [0025]    According to an exemplary embodiment, when it is determined based on the control signal that the source data is obtained by the second transceiver, the data transmission controller may discontinue transmitting the additional data segments. 
         [0026]    According to an aspect of another exemplary embodiment, receiving transceiver for transmitting and receiving data includes a receiving unit configured to receive at least one data segment among data segments of source data and parity data segments comprising restoration information for restoring the source data, from a transmitting transceiver, a data obtaining controller configured to determine that the source data is not obtained by the transmitting transceiver, based on the received at least one data segment; and a transmission unit configured to transmit a control signal indicating that the source data is not obtained, to the transmitting transceiver, based on a result of the determining. 
         [0027]    According to an exemplary embodiment, the data obtaining controller may identify the received at least one data segment, predict a quantity of parity data segments to be received after the identified at least one data segment, and compare a quantity of the predicted parity data segments and a quantity of the received at least one data segment with a quantity of data segments required to obtain the source data, and the transmission unit may request the required additional data segments, based on a result of comparing the quantity of the predicted parity data segments and the quantity of the received at least one data segment with the quantity of the required data segments. 
         [0028]    According to an exemplary embodiment, wherein the requesting of the additional data segment may include obtaining information indicating the required additional data segments. 
         [0029]    According to an exemplary embodiment, the data obtaining controller may predict a point of time at which the parity data segments are to be received, based on identification information of the received at least one source data segment and a point of time at which the received at least one data segment is received, and the transmission unit may request the additional data segments for obtaining the source data when the parity data segments are not received at the predicted point of time. 
         [0030]    According to an exemplary embodiment, the data obtaining controller may predict a data loss section, based on a point of time at which the received at least one data segment is received, the transmission unit may transmit information regarding the predicted data loss section to the transmitting transceiver, and a transmission section in which additional data segments for obtaining the source data are transmitted may be determined based on the information indicating the predicted data loss section. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    The above and/or other aspects will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings in which: 
           [0032]      FIG. 1  is a conceptual diagram illustrating a data transmitting and receiving system according to an exemplary embodiment; 
           [0033]      FIG. 2  is a flowchart of transmitting and receiving data, by using a first transceiver, according to an exemplary embodiment; 
           [0034]      FIG. 3  is a flowchart of transmitting and receiving data, by using a second transceiver, according to an exemplary embodiment; 
           [0035]      FIG. 4  is a diagram illustrating a method of determining a point of time when parity data is to be transmitted to a second transceiver, the method performed by a first transceiver, according to an exemplary embodiment; 
           [0036]      FIG. 5  is a flowchart of a method of determining a point of time when parity data is to be transmitted to a second transceiver, the method performed by a transmission device, according to an exemplary embodiment; 
           [0037]      FIG. 6  is a diagram illustrating a method of transmitting additional data segments from a transmission device to a second transceiver when the transmission device receives a negative-acknowledgement (NACK) signal from the second transceiver according to an exemplary embodiment; 
           [0038]      FIG. 7  is a flowchart of a method of determining whether source data is obtained, based on at least one segment received from a transmission device, the method performed by a second transceiver, according to an exemplary embodiment; 
           [0039]      FIG. 8  is a flowchart of a method of transmitting additional data segments from a transmission device to a second transceiver when the transmission device receives a NACK signal from the second transceiver according to an exemplary embodiment; 
           [0040]      FIG. 9  is a diagram illustrating a method of requesting a transmission device to provide additional data segments by predicting a point of time when the additional data segments are to be received, the method performed by a second transceiver, according to an exemplary embodiment; 
           [0041]      FIG. 10  is a flowchart of a method of requesting a first transceiver to provide additional data segments by predicting a point of time when the additional data segments are to be received, the method performed by a second transceiver, according to an exemplary embodiment; 
           [0042]      FIGS. 11A-B  are diagrams illustrating a method of changing a segment data transmission section in which data segments are transmitted by receiving information regarding a data loss section from a second transceiver, the method performed by a first transceiver, according to an exemplary embodiment; 
           [0043]      FIG. 12  is a flowchart of a method of transmitting information regarding a data loss section from a second transceiver to a first transceiver, according to an exemplary embodiment; 
           [0044]      FIG. 13  is a flowchart of a method of changing a transmission section, based on information regarding a data loss section received from a second transceiver, the method performed by a first transceiver, according to an exemplary embodiment; 
           [0045]      FIG. 14  is a flowchart of a method of discontinuing combining parity data of source data with subsequent source data according to an ACK signal received from a second transceiver, the method performed by a first transceiver, according to an exemplary embodiment; 
           [0046]      FIG. 15  is a block diagram of a first transceiver according to an exemplary embodiment; and 
           [0047]      FIG. 16  is a block diagram of a second transceiver according to an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0048]    Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present exemplary embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the exemplary embodiments are merely described below, by referring to the figures, to explain aspects. 
         [0049]    Before exemplary embodiments are described in detail, the terminology used in the present disclosure will be briefly described. 
         [0050]    In the present disclosure, general terms that have been widely used nowadays are selected, if possible, in consideration of functions of the inventive concept, but non-general terms may be selected according to the intentions of technicians in the art, precedents, or new technologies, etc. Also, some terms may be arbitrarily chosen by the present applicant. In this case, the meanings of these terms will be explained in corresponding parts of the present disclosure in detail. Thus, the terms used herein should be defined not based on the names thereof but based on the meanings thereof and the whole context of the inventive concept. 
         [0051]    It will be understood that the terms “comprise” and/or “comprising” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Also, the terms “unit”, “module”, etc. mean units for processing at least one function or operation and may be embodied as hardware, software, or a combination thereof. 
         [0052]    Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily accomplish them. However, an exemplary embodiment may be embodied in many different forms and the inventive concept is not limited to exemplary embodiments set forth herein. For clarity, elements that are not related to these exemplary embodiments are omitted in the drawings. Like reference numerals denote like elements throughout the specification. 
         [0053]    As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. 
         [0054]      FIG. 1  is a conceptual diagram illustrating a data transmitting and receiving system  5  (hereinafter referred to as ‘the system  5 ’) according to an exemplary embodiment; 
         [0055]    Referring to  FIG. 1 , the system  5  may include a first transceiver  100 , a first relay device  200 , a second relay device  300 , and a second transceiver  400 . 
         [0056]      FIG. 1  illustrates only components of the system  5  related to the present exemplary embodiment, but those of ordinary skill will understand that the system  5  may further include other general components. For example, the system  5  of  FIG. 1  may further include any quantity of relay devices, in addition to the first transceiver  100 , the first relay device  200 , the second relay device  300 , and the second transceiver  400 . 
         [0057]    The first transceiver  100  and the second transceiver  400  are computing devices having data processing capability and capability to perform wire or wireless communication with other devices. The first transceiver  100  and the second transceiver  400  exchange data  10 ,  20 , and  30  with each other via at least one among the first and second relay devices  200  and  300 . For example, the first transceiver  100  may transmit the data  10 ,  20 , and  30  to the first relay device  200 . The first relay device  200  may relay the data  10 ,  20 , and  30  received from the first transceiver  100  to the second relay device  300 . The second relay device  300  may relay the data  10 ,  20 , and  30  received from the first relay device  200  to the second transceiver  400 . 
         [0058]    The data  10 ,  20 , and  30  transmitted from the first transceiver  100  may include source data (e.g., the data  10 ), and parity data (e.g., the data  20 ) including restoration information for the source data. For example, the first parity data  20  may include restoration information for the first source data  10 . Here, the first parity data  20  may be obtained using error correction algorithms that have been used to obtain source data (e.g., the data  10 ). 
         [0059]    Also, the data  10 ,  20 , and  30  may include data segments having a preset size (e.g., data segments  12 ,  22 , and  32 ). For example, the first source data  10  may include a first-first source data segment  12 , a first-second source data segment  14 , a first-third source data segment  16 , and a first-fourth source data segment  18 . 
         [0060]    The second source data  30  may include a second-first source data segment  32 , a second-second source data segment  34 , a second-third source data segment  36 , and a second-fourth source data segment  38 . The first parity data  20  may include a first-first parity data segment  22 , a first-second parity data segment  24 , a first-third parity data segment  26 , and a first-fourth parity data segment  28 . 
         [0061]    According to an exemplary embodiment, the first transceiver  100  may combine parity segments  21  and the first parity data segments  22 ,  24 ,  26 , and  28  included in the first parity data  20  with the second source data segments  32 ,  34 ,  36 , and  38  included in the second source data  30 , and transmit a result of combining these parity segments with these second source data segments to the second transceiver  400 . However, exemplary embodiments are not limited thereto. 
         [0062]    In a wireless network environment, a data segment, e.g., the first-third source data segment  16 , may be lost due to a change in a routing path, channel interference, etc. For example, the first-third source data segment  16  included in the first source data  10  transmitted from the first transceiver  100  to the second transceiver  400  may be lost. 
         [0063]    According to an exemplary embodiment, the second transceiver  400  may determine whether the first source data  10  is obtained, based on at least one received data segment, for example, among the data segments  12 ,  14 ,  18 ,  22 . Also, the second transceiver  400  may transmit a control signal  40  representing whether the first source data  10  is obtained, to the first transceiver  100  that transmits the first source data  10 , based on a result of determining whether the first source data  10  is obtained. 
         [0064]    According to an exemplary embodiment, the control signal  40  may include information regarding the quantity of data segments required for the second transceiver  400  to obtain the first source data  10 . Also, the control signal  40  may include information regarding a data loss period predicted based on the at least one data segment received by the second transceiver  400  among the data segments  12 ,  14 ,  18 , and  22 . 
         [0065]    According to an exemplary embodiment, the first transceiver  100  may determine whether additional data segments for obtaining the first source data  10  are to be transmitted, based on the received control signal  40 . The first transceiver  100  may discontinue transmitting the additional data segment, when it is determined based on the control signal  40  that the second transceiver  400  obtains the first source data  10 . When the second transceiver  400  obtains the first source data  10 , the first transceiver  100  may discontinue transmitting the additional data segment, thereby efficiently using resources for transmitting and receiving data. 
         [0066]    According to another exemplary embodiment, the control signal  40  may be transmitted from the second transceiver  400  to the first transceiver  100  via a relay device other than the first relay device  200  and the second relay device  300 . 
         [0067]      FIG. 2  is a flowchart of transmitting and receiving data, by using the first transceiver  100  of  FIG. 1 , according to an exemplary embodiment. 
         [0068]    Referring to  FIGS. 1 and 2 , in operation S 210 , the first transceiver  100  transmits source data segments included in source data and parity data segments including restoration information for the source data to the second transceiver  400 . 
         [0069]    According to an exemplary embodiment, the first transceiver  100  may obtain a preset quantity of source data segments and a preset quantity of parity data segments. For example, when the first transceiver  100  employs forward error correction (FEC), the first transceiver  100  may generate a data block including k source data segments and (n-k) parity data segments. 
         [0070]    According to an exemplary embodiment, the source data segments and the parity data segments included in the data block may be transmitted to the second transceiver  100  in units of segments. 
         [0071]    The first transceiver  100  may transmit at least one source data segment included in the data block to the second transceiver  400 . Here, the at least one source data segment may be unit data obtained by dividing the source data according to time or a data size. 
         [0072]    Also, according to an exemplary embodiment, the first transceiver  100  may transmit at least one parity data segment to the second transceiver  400 . The first transceiver  100  may transmit parity data to the second transceiver  400  according to at least one of a burst transmission method and a distributed transmission method. In the burst transmission method, the first transceiver  100  transmits the parity data to the second transceiver  400  as soon as the parity data is generated. In the distributed transmission method, parity data generated by the first transceiver  100  is transmitted to the second transceiver  400  at predetermined time intervals. 
         [0073]    In operation S 220 , the first transceiver  100  receives from the second transceiver  400  a control signal  40  representing whether the source data is obtained, the control signal  40  determined based on at least one data segment among the source data segments and the parity data segments. The control signal  40  may include information indicating whether the second transceiver  400  obtains the source data. 
         [0074]    According to an exemplary embodiment, the first transceiver  100  may receive an acknowledgement (ACK) signal from the second transceiver  400  when the second transceiver  400  receives the source data based on the received at least one data segment. 
         [0075]    In contrast, the first transceiver  100  may receive a negative-acknowledgement (NACK) signal from the second transceiver  400  when the second transceiver  400  does not receive the source data based on the received at least one data segment. Also, when the second transceiver  400  cannot obtain the source data, the first transceiver  100  may receive information regarding the quantity of additional data segments required to obtain the source data. 
         [0076]    According to an exemplary embodiment, the first transceiver  100  may receive information regarding a data loss section in which the source data is damaged from the second transceiver  400 , as will be described in detail with reference to  FIG. 13 . 
         [0077]    In operation S 230 , the first transceiver  100  determines whether additional data segments for obtaining the source data are to be transmitted, based on the control signal  40 . 
         [0078]    According to an exemplary embodiment, when receiving the ACK signal from the second transceiver  400 , the first transceiver  100  may not transmit the additional data segments. 
         [0079]    According to an exemplary embodiment, when receiving the NACK signal from the second transceiver  400 , the first transceiver  100  may transmit the additional data segments to the second transceiver  400 . The additional data segments may include at least one among the source data segments that constitute the source data and the parity data segments that constitute the parity data. 
         [0080]    According to an exemplary embodiment, the first transceiver  100  may transmit additional data segments to the second transceiver  400 , based on information regarding the quantity of additional data segments required to obtain the source data, the information received from the second transceiver  400 . Also, the first transceiver  100  may change the size of a data block, based on the information regarding the quantity of the additional data segments required to obtain the source data, the information received from the second transceiver  400 . For example, the first transceiver  100  changes the size of a data block including k source data segments and (n-k) parity data segments by adding parity data segments to the data block. 
         [0081]      FIG. 3  is a flowchart of transmitting and receiving data, by using a second transceiver  400 , according to an exemplary embodiment. 
         [0082]    Referring to  FIGS. 1 and 3 , in operation S 310 , the second transceiver  400  receives from the first transceiver  100  at least one data segment among source data segments included in source data and parity data segments including restoration information for the source data. 
         [0083]    Some data segments among the at least one data segment transmitted from the first transceiver  100  to the second transceiver  400  may be lost due to a change in a network environment, e.g., a change in a routing path or channel interference. 
         [0084]    The second transceiver  400  may receive at least some of the at least one source data segment transmitted from the first transceiver  100 . Also, the second transceiver  400  may receive at least some of at least one parity data segment transmitted from the first transceiver  100 . 
         [0085]    In operation S 320 , the second transceiver  400  determines whether the source data is obtained, based on the received at least one data segment. 
         [0086]    According to an exemplary embodiment, the second transceiver  400  may compare the quantity of the received at least one data segment with the quantity of data segments required to obtain the source data. For example, the second transceiver  400  may determine that the source data may be obtained when the quantity of the received at least one data segment is greater than or equal to the quantity of data segments required to obtain the source data. 
         [0087]    However, a method of determining whether the source data is obtained, based on the received at least one data segment, the method performed by the second transceiver  400 , is not limited thereto. 
         [0088]    In operation S 330 , the second transceiver  400  transmits a control signal representing whether the source data is obtained, to the first transceiver  100  that transmits the source data, based on the result of determining whether the source data is obtained. 
         [0089]    According to an exemplary embodiment, when the source data is obtained from the received at least one data segment, the second transceiver  400  may transmit an ACK signal to the first transceiver  100 . When the source data is not obtained from the received at least one data segment, the second transceiver  400  may transmit a NACK signal to the first transceiver  100 . When the source data is not obtained from the received at least one data segment, the second transceiver  400  may transmit, as a control signal, information regarding the quantity of additional data segments for obtaining the source data to the first transceiver  100 . 
         [0090]    According to another exemplary embodiment, the second transceiver  400  may predict a data loss section, based on an identification (ID), for example an ID number, of the at least one data segment and a point of time at which the at least one data segment is received. The second transceiver  400  may transmit information regarding the predicted data loss section to the first transceiver  100 , as will be described in detail with reference to  FIG. 12  below. 
         [0091]      FIG. 4  is a diagram illustrating a method of determining a point of time when parity data is to be transmitted to a second transceiver  400 , the method performed by a first transceiver  100 , according to an exemplary embodiment 
         [0092]    The first transceiver  100  may transmit first source data  410  to the second transceiver  400  which is a transmission destination according to a multi-hop method. For example, the first source data  410  may be transmitted from the first transceiver  100  to the second transceiver  400  via a first relay device  200  and a second relay device  300 . 
         [0093]    The first transceiver  100  may generate first parity data  420  including restoration information for the first source data  410 . After transmitting the first source data  410 , the first transceiver  100  may transmit the first parity data  420  to the second transceiver  400 . 
         [0094]    According to an exemplary embodiment, the first transceiver  100  may transmit the first parity data  420  after a data round-trip time between the first transceiver  100  and the second transceiver  400 , starting from a point of time at which the transmission of the first source data  410  is ended. The first transceiver  100  may not transmit the first parity data  420  within the data round-trip time during which an ACK signal may arrive to the first transceiver  100  from the second transceiver  400 , thereby allowing the first source data  410  to be received by the second transceiver  400  while preventing the first parity data  420  from being received by the second transceiver  400 . 
         [0095]    The first parity data  420  may be also transmitted from the first transceiver  410  to the second transceiver  400  according to the multi-hop method. 
         [0096]    The first parity data  420  generated by the first transceiver  100  may include a first burst parity data set  423  transmitted according to the burst transmission method, and first distributed parity data segments  422 ,  424 ,  426 , and  428  transmitted according to the distributed transmission method. The first burst parity data set  423  may include a plurality of parity data segments. 
         [0097]    Referring to  FIG. 4 , the second transceiver  400  may receive all of source data segments included in the first source data  410 . When the second transceiver  400  receives all of the source data segments included in the first source data  410 , the second transceiver  400  may transmit an ACK signal indicating that the first source data  410  is obtained, to the first transceiver  100 . 
         [0098]    When receiving the ACK signal from the second transceiver  400 , the first transceiver  100  may not transmit the second parity data  420 . 
         [0099]    According to another exemplary embodiment, when the first transceiver  100  does not receive the ACK signal from or receives a NACK signal from the second transceiver  400 , the first transceiver  100  may transmit a combination of the first parity data  420  and the second source data  430  to the second transceiver  400 . However, exemplary embodiments are not limited thereto, and the first transceiver  100  may transmit the first parity data  420  and the second source data  430  separately to the second transceiver  400 , 
         [0100]      FIG. 5  is a flowchart of a method of determining a point of time when parity data is to be transmitted to a second transceiver, the method performed by a first transceiver, according to an exemplary embodiment. 
         [0101]    Referring to  FIGS. 1 and 5 , in operation S 510 , the first transceiver  100  may transmit source data to the second transceiver  400 . Here, the first transceiver  100  may transmit the source data to the second transceiver  400  according to the multi-hop method via at least one relay device among the relay devices  200  and  300 . 
         [0102]    In operation S 520 , the first transceiver  100  may determine whether an ACK signal is received before a data round-trip time between the first transceiver  100  and the second transceiver  400 , starting from a point of time at which the transmission of the source data is completed. Here, the ACK signal may be transmitted from the second transceiver  400  to the first transceiver  100  when the second transceiver  400  receives the source data. 
         [0103]    In operation S 530 , the first transceiver  100  may transmit a parity data set including a plurality of parity data segments to the second transceiver  400  after the data round-trip time, starting from the point of time at which the transmission of the source data is completed. 
         [0104]    According to an exemplary embodiment, the first transceiver  100  may change a point of time at which the parity data set is to be transmitted to the second transceiver  400  to be a point of time after the data round-trip time, starting from the point of time at which the transmission of the source data is completed. The first transceiver  100  may transmit the parity data set after a point of time at which the ACK signal may be received from the second transceiver  400 , so that the parity data set may be transmitted to the second transceiver  400  after determining whether the second transceiver  400  obtains the source data. 
         [0105]    In operation S 540 , the first transceiver  100  may transmit subsequent source data to the second transceiver  400 . 
         [0106]    According to an exemplary embodiment, when the first transceiver  100  receives the ACK signal before the data round-trip time, starting from the point of time at which the transmission of the source data is completed, the first transceiver  100  may transmit the subsequent source data to the second transceiver  400 . 
         [0107]    The first transceiver  100  may transmit the subsequent source data to the second transceiver  400  according to the ACK signal received from the second transceiver  400  without transmitting the parity data of the completely transmitted source data to the second transceiver  400 , thereby efficiently using network resources. 
         [0108]      FIG. 6  is a diagram illustrating a method of transmitting additional data segments from a first transceiver  100  to a second transceiver  400  when the first transceiver  100  receives a NACK signal from the second transceiver  400  according to an exemplary embodiment. 
         [0109]    Referring to  FIG. 6 , the first transceiver  100  may transmit first source data  610  to the second transceiver  400  via relay devices  200  and  300  according to the multi-hop method. For example, the first source data  610  may be transmitted from the first transceiver  100  to the second transceiver  400  via the first relay device  200  and the second relay device  300 . The first source data  610  may include a plurality of first source data segments  612 ,  614 ,  616 , and  618 . 
         [0110]    The first transceiver  100  may generate first parity data  620  including restoration information for the first source data  610 . The first transceiver  100  may transmit the first parity data  620  to the second transceiver  400  via the first relay device  200  and the second relay device  300 . The first parity data  620  may include a parity data set  621  and a plurality of parity data segments  622 ,  623 ,  624 , and  625 . 
         [0111]    At least one data segment among the source data segments included in the first source data  610  and the parity data segments included in the first parity data  620  may be lost before the second transceiver  400  receives the first source data  610  and the first parity data  620 . Referring to  FIG. 6 , data segments  640  that are lost may include the three first source data segments  614 ,  616 , and  618 , the parity data set  621 , and the three parity data segments  622 ,  623 , and  624 . 
         [0112]    The second transceiver  400  may predict the quantity of the other data segments that have yet to be received, based on the data segment  624  that is lastly received among received at least one data segment of, for example, the data segments  612  and  624 . For example, the second transceiver  400  may predict that the quantity of the other data segment(s)  625  is ‘1’, based on an ID number of the lastly received data segment  624 . 
         [0113]    According to an exemplary embodiment, if the second transceiver  400  determines that the first source data  610  cannot be obtained even when the other data segment  625  is received, the second transceiver  400  may transmit a NACK signal  640  representing that the first source data  610  cannot be obtained to the first transceiver  100 . Also, the second transceiver  400  may transmit, to the first transceiver  100 , information regarding the quantity of additional data segments required to obtain the first source data  610 , together with the NACK signal  640 . 
         [0114]    When receiving the NACK signal  640  from the second transceiver  400 , the first transceiver  100  may transmit the additional data segments required to obtain the first source data  610  to the second transceiver  400 . The NACK signal  640  may include information regarding source data segments that are not received by the second transceiver  400 . The first transceiver  100  may retransmit the source data segments specified in the information regarding source data segments that are not received. Also, the first transceiver  100  may transmit parity data segments including restoration information for the specified source data segments to the second transceiver  400 . 
         [0115]      FIG. 7  is a flowchart of a method of determining whether source data is obtained, based on at least one segment received from a first transceiver, the method performed by a second transceiver, according to an exemplary embodiment. 
         [0116]    Referring to  FIGS. 1 and 7 , in operation S 710 , the second transceiver  400  may receive at least one data segment among source data segments included in source data and parity data segments regarding the source data from the first transceiver  100 . 
         [0117]    According to an exemplary embodiment, the second transceiver  400  may receive at least one data segment among the source data segments and the parity data segments via at least one relay device (e.g., a relay device  200 ) between the second transceiver  400  and the first transceiver  100  according to the multi-hop method. 
         [0118]    In operation S 720 , the second transceiver  400  may identify the received at least one data segment, and predict the quantity of parity data segments to be received after the received at least one data segment. 
         [0119]    In the second transceiver  400 , information regarding the quantity of at least one source data segment and the quantity of at least one parity segment to be transmitted from the first transceiver  100  may be stored beforehand. Also, ID numbers may be respectively assigned to the at least one source data segment and the at least one parity segment to be transmitted from the first transceiver  100 . 
         [0120]    According to an exemplary embodiment, the second transceiver  400  may predict the quantity of parity data segments that have yet to be received among all of the parity data segments transmitted from the first transceiver  100 , based on the ID quantity of a parity data segment received lastly. For example, the quantity of all of the parity data segments transmitted from the first transceiver  100  may be four, and ‘1’ to ‘4’ may be respectively assigned as ID numbers to the parity data segments. When the ID number of a parity data segment lastly received is ‘3’, the second transceiver  400  may identify that the quantity of the remaining parity data segment that has yet to be received is one. 
         [0121]    In operation S 730 , the second transceiver  400  may compare the predicted quantity of the parity data segments and the quantity of the received at least one data segment with the quantity of data segments required to obtain the source data. 
         [0122]    In the second transceiver  400 , information regarding the quantity of data segments required to obtain the source data may be stored. For example, the second transceiver  400  may receive four or more source data segments from the first transceiver  400  so as to obtain source data including four source data segments. Here, the four or more data segments may include all of the source data segments and the parity data segments. 
         [0123]    In operation S 740 , the second transceiver  400  may transmit the NACK signal and information regarding the quantity of additional data segments required to obtain the source data to the first transceiver  100 . 
         [0124]    According to an exemplary embodiment, the second transceiver  400  may determine that the source data cannot be obtained when the sum of the quantity of the received data segments and the quantity of the remaining data segments is less than the quantity of data segments required to obtain the source data. When it is determined that the source data cannot be obtained, the second transceiver  400  may transmit the NACK signal and information regarding the quantity of additional data segments required to obtain the source data to the first transceiver  100 . 
         [0125]    However, exemplary embodiments are not limited thereto, and the second transceiver  400  may transmit either the NACK signal or the information regarding the quantity of additional data segments required to obtain the source data to the first transceiver  100 . 
         [0126]    In operation S 750 , the second transceiver  400  may receive the remaining data segments from the first transceiver  100 . 
         [0127]    The second transceiver  400  may determine that the source data may be obtained when the sum of the quantity of the received data segments and the quantity of the remaining data segments is equal to or greater than the quantity of data segments required to obtain the source data. When it is determined that the source data may be obtained, the second transceiver  400  may receive the remaining data segments from the first transceiver  100 . 
         [0128]      FIG. 8  is a flowchart of a method of transmitting additional data segments from a first transceiver to a second transceiver when the first transceiver receives the NACK signal from the second transceiver according to an exemplary embodiment. 
         [0129]    Referring to  FIGS. 1 and 8 , in operation S 810 , the first transceiver  100  may transmit source data segments included in source data and parity data segments including restoration information for the source data to the second transceiver  400 . 
         [0130]    According to an exemplary embodiment, the first transceiver  100  may transmit at least one data segment among the source data segments and the parity data segments to the second transceiver  400  via at least one relay device (e.g., the relay device  200 ) between the first transceiver  100  and the second transceiver  400  according to the multi-hop method. 
         [0131]    In operation S 820 , the first transceiver  100  may determine whether the NACK signal and information regarding a quantity of additional data segments required to obtain the source data are received from the second transceiver  400 . 
         [0132]    Here, the NACK signal and the information regarding the additional data segments may be received from the second transceiver  400  when the second transceiver  400  determines based on the received at least one data segment that the source data is difficult to obtain. 
         [0133]    In operation S 830 , the first transceiver  100  may transmit the remaining data segments that have yet to be transmitted to the second transceiver  400 . When the first transceiver  100  does not receive the NACK signal and the information regarding the additional data segments from the second transceiver  400 , the first transceiver  100  may transmit the remaining data segments that have yet to be transmitted to the second transceiver  400 . 
         [0134]    In operation S 840 , the first transceiver  100  may transmit additional data segments to the second transceiver  400  based on the received information regarding the quantity of the additional data segments. 
         [0135]    According to an exemplary embodiment, when the first transceiver  100  receives the NACK signal and the information regarding the additional data segments from the second transceiver  400 , the first transceiver  100  may transmit the additional data segments to the second transceiver  400 . For example, when the transmission device  100  receives information indicating that three data segments are required to obtain the source data, the first transceiver  100  may transmit the three additional data segments to the second transceiver  400 . 
         [0136]      FIG. 9  is a diagram illustrating a method of requesting a first transceiver  100  to provide additional data segments by predicting a point of time when the additional data segments are to be received, the method performed by a second transceiver  400 , according to an exemplary embodiment. 
         [0137]    Referring to  FIG. 9 , the first transceiver  100  may transmit first source data  910  to the second transceiver  400  via a first relay device  200  and a and second relay device  300  according to the multi-hop method. For example, the first source data  910  may be transmitted from the first transceiver  100  to the second transceiver  400  via the first relay device  200  and the second relay device  300 . The first source data  910  may include a plurality of first source data segments  912 ,  914 ,  916 , and  918 . 
         [0138]    The first transceiver  100  may generate first parity data  920  including restoration information for the first source data  910 . The first transceiver  100  may transmit the first parity data  920  to the second transceiver  400  via the first relay device  200  and the second relay device  300 . The first parity data  920  may include a parity data set  921  and a plurality of parity data segments  922 ,  923 ,  924 , and  925 . 
         [0139]    According to an exemplary embodiment, the second transceiver  400  may predict a point of time at which subsequent data segments will be received, based on ID information of at least one data segment among the received data segments, e.g., the data segments  912  and  918 , and a point of time at which the data segments  912  and  918  are received. Also, the second transceiver  400  may predict a point of time at which a specific data segment will be received. For example, the second transceiver  400  may predict a point of time at which the parity data set  921  transmitted after the transmission of the source data is to be received, based on an ID quantity of the source data segment  918  received lastly. 
         [0140]    When the data segments are not received at the predicted point of time, the second transceiver  400  may transmit a request  940  for additional data segments required to obtain the source data to the first transceiver  100 . The request  940  for the additional data segment may include information regarding the quantity of the additional data segments required to obtain the source data. For example, when the parity data set  921  is not received at the predicted point of time, the second transceiver  400  may transmit the request  940  for the additional data segments to the first transceiver  100 . 
         [0141]    The second transceiver  400  may predict a point of time at which a subsequent data segment to be received, and request the first transceiver  100  to provide the additional data segment when the subsequent data segment is not received at the predicted point of time. 
         [0142]      FIG. 10  is a flowchart of a method of requesting a first transceiver to provide additional data segments by predicting a point of time when the additional data segments are to be received, the method performed by a second transceiver, according to an exemplary embodiment. 
         [0143]    Referring to  FIGS. 1 and 10 , in operation S 1010 , the second transceiver  400  may receive at least one source data segment among a plurality of source data segments included in source data. 
         [0144]    According to an exemplary embodiment, the second transceiver  400  may receive the at least one source data segment via at least one relay device (e.g., the relay device  200 ) between the second transceiver  400  and the first transceiver  100  according to the multi-hop method. 
         [0145]    In operation S 1020 , the second transceiver  400  may predict a point of time at which parity data segments will be received, based ID information of the at least one source data segment and the point of time at which the at least one source data segment is received. 
         [0146]    According to an exemplary embodiment, the second transceiver  400  may predict time intervals at which data segments will be transmitted from the first transceiver  100 , based the ID information of the at least one source data segment and the point of time at which the at least one source data segment is received. 
         [0147]    The second transceiver  400  may predict a point of time at which parity data segments will be received, based on the predicted time intervals. 
         [0148]    In operation S 1030 , the second transceiver  400  may determine whether the parity data segments are received at the predicted point of time. For example, the second transceiver  400  may determine whether a parity data set is received at the predicted point of time. 
         [0149]    In operation S 1040 , the second transceiver  400  may request the first transceiver  100  to provide additional data segments. When the parity data segments are not received at the predicted point of time, the second transceiver  400  may request the first transceiver  100  to provide the additional data segments. 
         [0150]    In operation S 1050 , the second transceiver  400  may obtain the source data, based on the received parity data segments. The second transceiver  400  may obtain the source data from the received parity data segments and the received source data segments. 
         [0151]      FIG. 11  is a diagram illustrating a method of changing a data segment transmission section by receiving information regarding a data loss section from a second transceiver  400 , the method performed by a first transceiver  100 , according to an exemplary embodiment. 
         [0152]    Referring to  FIG. 11A , the first transceiver  100  may transmit first source data  1110  to the second transceiver  400  via a first relay device  200  and a second relay device  300  according to the multi-hop method. For example, the first source data  1110  may be transmitted from the first transceiver  100  to the second transceiver  400  via the first and second relay devices  200  and  300 . The first source data  1110  may include a plurality of first source data segments  1112 ,  1114 ,  1116 , and  1118 . 
         [0153]    The first transceiver  100  may generate first parity data  1120  including restoration information for the first source data  1110 . The first transceiver  100  may transmit the first parity data  1120  to the second transceiver  400  via the first and second relay devices  200  and  300 . The first parity data  1120  may include a parity data set  1121 , and a plurality of first parity data segments  1122 ,  1123 ,  1124 , and  1125 . 
         [0154]    Consecutive data loss sections may occur between the first transceiver  100  and the second transceiver  400  in a network. In this case, a data transmission section  1130  corresponds to the consecutive data loss sections. Thus, at least one data segment transmitted from the first transceiver  100  may be continuously lost. For example, referring to  FIG. 11A , three first source data segments  1114 ,  1116 , and  1118 , a parity data set  1121 , and two parity data segments  1122  and  1124  may be lost in the consecutive data loss sections between the first transceiver  100  and the second transceiver  400 . 
         [0155]    Referring to  FIG. 11B , the first transceiver  100  may transmit second source data  1140  to the second transceiver  400  via the first and second relay devices  200  and  300  according to the multi-chip method. The second source data  1140  may include a plurality of second source data segments  1142 ,  1144 ,  1146 , and  1148 . 
         [0156]    The first transceiver  100  may also transmit second parity data  1150  to the second transceiver  400  via the first relay device  200  and the second relay device  300 . The second parity data  1150  may include a parity data set  1151  and a plurality of second parity data segments  1152 ,  1153 ,  1154 , and  1155 . 
         [0157]    According to an exemplary embodiment, the second transceiver  400  may predict a data loss section in a network, based on received at least one data segment. The second transceiver  400  may transmit information regarding the predicted data loss section to the first transceiver  100 . 
         [0158]    The first transceiver  100  may change a transmission section for transmitting different data segments to the second transceiver  400 , based on the information regarding the predicted data loss section received from the second transceiver  400 . Referring to  FIG. 11B , the first transceiver  100  may transmit different data segments  1154 ,  1156 , and  1158  to the second transceiver  400 , based on a changed data transmission section  1170 , thereby preventing a loss in the different data segments  1154 ,  1156 , and  1158 . 
         [0159]      FIG. 12  is a flowchart of a method of transmitting information regarding a data loss section from a second transceiver to a first transceiver according to an exemplary embodiment. 
         [0160]    Referring to  FIGS. 1 and 12 , in operation S 1210 , the second transceiver  400  may receive at least one data segment among source data segments included in source data and parity data segments regarding the source data from the first transceiver  100 . 
         [0161]    Operation S 1210  may correspond to operation S 710  described above with reference to  FIG. 7 . 
         [0162]    In operation S 1220 , the second transceiver  400  may predict a data loss section between the second transceiver  400  and the first transceiver  100 , based on information regarding a point of time at which the received at least one data segment is received. 
         [0163]    For example, the second transceiver  400  may detect an ID number of the received at least one data segment. Also, the second transceiver  400  may predict at least one of the quantity of data segments lost for a predetermined time and a data loss section in which a data segment is lost, based on the information regarding a point of time at which the received at least one data segment is received. 
         [0164]    In operation S 1230 , the second transceiver  400  may transmit information indicating the predicted data loss section to the first transceiver  100 . 
         [0165]    According to an exemplary embodiment, the second transceiver  400  may transmit the information indicating the predicted data loss section to the first transceiver  100  via a path that is substantially the same as a path over which the at least one data is received. According to another exemplary embodiment, the second transceiver  400  may transmit the information regarding the predicted data loss section to the first transceiver  100  via a path that is different from the path over which the at least one data is received. 
         [0166]      FIG. 13  is a flowchart of a method of changing a transmission section, based on information regarding a data loss section received from a second transceiver, the method performed by a first transceiver, according to an exemplary embodiment. 
         [0167]    Referring to  FIGS. 1 and 13 , in operation S 1310 , the first transceiver  100  may transmit source data segments included in source data and parity data segments including restoration information for the source data to the second transceiver  400 . 
         [0168]    Operation S 1310  may correspond to operation S 810  as described above with reference to  FIG. 8 . 
         [0169]    In operation S 1320 , the first transceiver  100  may receive, from the second transceiver  400 , information regarding a data loss section predicted based on at least one data segment received by the second transceiver  400  among the transmitted source data segments and parity data segments. 
         [0170]    In operation S 1330 , the first transceiver  100  may transmit additional data segments according to a data transmission section changed based on the predicted data loss section. 
         [0171]    According to an exemplary embodiment, the first transceiver  100  may change a preset data transmission section based on the information regarding the predicted data loss section. For example, when the preset data transmission section corresponds to the predicted data loss section, the first transceiver  100  may change the data transmission section to be wider than the predicted data loss section. When the preset data transmission section has a width of ‘a’ and the predicted data loss section has a width of ‘1.2a,’ the first transceiver  100  may change the data transmission section to have a width of ‘1.5a.’ 
         [0172]    Also, the first transceiver  100  may transmit additional data segments to the second transceiver  400  according to the changed data transmission section. 
         [0173]      FIG. 14  is a flowchart of a method of discontinuing combining parity data of source data with subsequent source data according to an ACK signal received from a second transceiver, the method performed by a first transceiver, according to an exemplary embodiment. 
         [0174]    Referring to  FIGS. 1 and 14 , in operation S 1410 , the first transceiver  100  may transmit source data to the second transceiver  400 . The first transceiver  100  may transmit the source data to the second transceiver  400  via at least one among the relay devices  200  and  300  according to the multi-chip method. 
         [0175]    In operation S 1420 , the first transceiver  100  may determine whether the ACK signal is received. The ACK signal may be transmitted from the second transceiver  400  to the first transceiver  100  when the second transceiver  400  receives the source data. 
         [0176]    In operation S 1430 , the first transceiver  100  may combine source data subsequent to the source data with additional data segments, and transmit a result of combining the subsequent source data with the additional data segments to the second transceiver  400 . 
         [0177]    According to an exemplary embodiment, when the first transceiver  100  does not receive the ACK signal, the first transceiver  100  may combine additional data segments required to obtain the source data with the subsequent source data, and transmit a result of combining the required additional data segments with the subsequent source data to the second transceiver  400 . 
         [0178]    In operation S 1440 , the first transceiver  100  may transmit the subsequent source data to the second transceiver  400 . 
         [0179]    According to an exemplary embodiment, when the first transceiver  100  receives the ACK signal, the first transceiver  100  may transmit the subsequent source data to the second transceiver  400 . When the first transceiver  100  receives the ACK signal, the first transceiver  100  may determine that the second transceiver  400  obtains the source data and may thus not transmit the additional data segments required to obtain the source data to the second transceiver  400 . 
         [0180]      FIG. 15  is a block diagram of a first transceiver  100  according to an exemplary embodiment. 
         [0181]    Referring to  FIG. 15 , the first transceiver  100  may include a transmission unit  110 , a receiving unit  120 , and a data transmission controller  130 . 
         [0182]      FIG. 15  illustrates only components of the first transceiver  100  that are related to the present embodiment, but those of ordinary skill in the art will understand that the first transceiver  100  may include other components. 
         [0183]    Referring to  FIGS. 1 and 15 , the transmission unit  110  transmits source data segments included in source data and parity data segments including restoration information for the source data to the second transceiver  400 . 
         [0184]    The receiving unit  120  receives from the second transceiver  400  a control signal indicating whether the source data is obtained, the control signal determined based on at least one data segment among the source data segments and the parity data segments. 
         [0185]    The receiving unit  120  may receive the ACK signal when the second transceiver  400  may obtain the source data based on the received at least one data segment. 
         [0186]    The receiving unit  120  may receive the NACK signal when the second transceiver  400  cannot obtain the source data based on the received at least one data segment. Also, when the second transceiver  400  cannot obtain the source data, the receiving unit  120  may receive information regarding the quantity of additional data segments required to obtain the source data. As another example, the receiving unit  120  may receive information regarding a data loss section in which the source data is damaged from the second transceiver  400 . 
         [0187]    The data transmission controller  130  determines whether the additional data segments required to obtain the source data are to be transmitted, based on the received control signal  40 . 
         [0188]    When an ACK signal including information indicating that the source data may be obtained is received from the second transceiver  400 , the data transmission controller  130  may control the transmission unit  110  to discontinue transmission of the additional data segments. The additional data segments may include at least one among the source data segments that constitute the source data and the parity data segments that constitute parity data. 
         [0189]    When a NACK signal including information representing that the source data cannot be obtained is received from the second transceiver  400 , the data transmission controller  130  may control the transmission unit  110  to transmit the additional data segments to the second transceiver  400 . Also, the data transmission controller  130  may control the transmission unit  110  to transmit the additional data segments to the second transceiver  400 , based on the information regarding the quantity of the required additional data segments. As another example, the data transmission controller  130  may control a time period for which the transmission unit  110  will transmit the additional data segments to the second transceiver  400 . 
         [0190]    The data transmission controller  130  may determine a point of time at which a parity data set including a plurality of parity data segments will be transmitted to be a point of time after a data round-trip time between the first transceiver  100  and the second transceiver  400 , starting from a point of time at which the transmission of the source data is completed. 
         [0191]    Also, the data transmission controller  130  may change a transmission section in which the additional data segments are to be transmitted to the second transceiver  400 , based on information regarding a data loss section received by the receiving unit  120 . 
         [0192]    According to an exemplary embodiment, when the receiving unit  120  receives the NACK signal, the data transmission controller  130  may discontinue combining the parity data segments including the restoration information for the source data with source data segments included in subsequent source data. 
         [0193]    According to an exemplary embodiment, the first transceiver  100  may include a data encoder configured to generate the source data segments and the parity data segment. 
         [0194]      FIG. 16  is a block diagram of a second transceiver according to an exemplary embodiment. 
         [0195]    Referring to  FIG. 16 , the second transceiver  1600  may include a receiving unit  1610 , a data obtaining controller  1620 , and a transmission unit  1630 . The second transceiver  1600  may correspond to the second transceiver  400  discussed above. 
         [0196]      FIG. 16  illustrates only components of the second transceiver  1600  that are related to the present embodiment but it would be apparent to those of ordinary skill in the art that the second transceiver  1600  may further include other general components. 
         [0197]    Referring to  FIGS. 1 and 16 , the receiving unit  1610  receives from the first transceiver  100  at least one data segment among source data segments included in source data and parity data segments including restoration information for the source data. The receiving unit  1610  may receive at least one data segment that is not damaged by a change in a network environment, e.g., a change in a routing path or channel interference, among the source data segment and the parity data segments transmitted from the first transceiver  100 . 
         [0198]    The data obtaining controller  1620  determines whether the source data may be obtained, based on the received at least one data segment. 
         [0199]    According to an exemplary embodiment, the data obtaining controller  420  may compare the quantity of the received at least one data segment with the quantity of data segments required to obtain the source data. The data obtaining controller  1620  may determine that the source data may be obtained when the quantity of the received at least one data segment is equal to or greater than the quantity of data segments required to obtain the source data. 
         [0200]    Also, the data obtaining controller  1620  may predict a point of time at which the parity data segments will be received, based on ID information of the received at least one source data segment and a point of time at which the received at least one source data segment is received. When the parity data segments are not received at the predicted point of time, the data obtaining controller  1620  may control the transmission unit  1630  to request the first transceiver  100  to provide additional data segments to obtain the source data. 
         [0201]    The transmission unit  1630  transmits a control signal representing whether the source data is obtained to the first transceiver  100  that transmits the source data, based on the determination of the data obtaining controller  1620 . For example, when the data obtaining controller  1620  determines that the source data may be obtained, based on the received at least one data segment, the transmission unit  1630  may transmit the ACK signal to the first transceiver  100 . When the data obtaining controller  1620  determines that the source data cannot be obtained, based on the received at least one data segment, the transmission unit  1630  may transmit the NACK signal to the first transceiver  100 . Also, when the data obtaining controller  1620  determines that the source data cannot be obtained, based on the received at least one data segment, the transmission unit  1630  may transmit, as a control signal, information regarding the quantity of additional data segments required to obtain the source data to the first transceiver  100 . 
         [0202]    Also, the transmission unit  1630  may transmit, as a control signal, information indicating a predicted data loss section to the first transceiver  100 . The data loss section may be predicted by the data obtaining controller  1620 , based on an ID quantity assigned to the at least one data segment received by the receiving unit  1610 . 
         [0203]    According to an exemplary embodiment, the second transceiver  1600  may include a data decoder configured to decode received source data segments and parity data segments. 
         [0204]    The devices or apparatuses according to the exemplary embodiments set forth herein may include a processor, a memory for storing and executing program data, a permanent storage such as a disk drive, a communication port for communicating with an external device, a user interface device such as a touch panel, keys, buttons, etc. Methods that may be embodied as software modules or algorithms may be stored in a computer readable recording medium in the form of computer readable codes or program instructions that can be executed in the processor. Examples of the computer readable recording medium include a magnetic recording medium (e.g., read-only memory (ROM), random-access memory (RAM), a floppy disk, a hard disc, etc.), an optical recording medium (e.g., compact-disk ROM (CD-ROM), a digital versatile disc ((DVD)), and so on. The computer readable medium can be distributed among computer systems that are interconnected through a network, and exemplary embodiments may be stored and implemented as computer readable code in a distribution manner. The computer readable recording medium can be read by a computer, stored in a memory, and executed by a processor. 
         [0205]    All references including publications, patent applications, and patents, cited herein, are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
         [0206]    To help understand the exemplary embodiments set forth herein, reference numerals are used in the exemplary embodiments illustrated in the drawings and specific terms are used to explain these embodiments. However, the exemplary embodiments not limited by the specific terms. The exemplary embodiments may cover all components that are obvious to those of ordinary skill in the art. 
         [0207]    The exemplary embodiments set forth herein may be represented using functional block components and various operations. Such functional blocks may be realized by any number of hardware and/or software components configured to perform specified functions. For example, the exemplary embodiments may employ various integrated circuit components, e.g., memory, processing elements, logic elements, look-up tables, and the like, which may carry out a variety of functions under control of at least one microprocessor or other control devices. As the elements of the exemplary embodiments are implemented using software programming or software elements, the exemplary embodiments may be implemented with any programming or scripting language such as C, C++, Java, assembler, or the like, including various algorithms that are any combination of data structures, processes, routines or other programming elements. Functional aspects may be realized as an algorithm executed by at least one processor. Furthermore, the exemplary embodiments may employ conventional techniques for electronics configuration, signal processing and/or data processing. The terms ‘mechanism’, ‘element’, ‘means’, ‘configuration’, etc. are used broadly and are not limited to mechanical or physical embodiments. These terms should be understood as including software routines in conjunction with processors, etc. 
         [0208]    The particular implementations shown and described herein are exemplary embodiments and are not intended to otherwise limit the scope of the inventive concept in any way. For the sake of brevity, conventional electronics, control systems, software development and other functional aspects of the systems may not be described in detail. Furthermore, the lines or connecting elements shown in the appended drawings are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections or logical connections may be present in a practical device. Moreover, no item or component is essential to the practice of the inventive concept unless it is specifically described as “essential” or “critical”. 
         [0209]    It should be understood that exemplary embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each exemplary embodiment should typically be considered as available for other similar features or aspects in other exemplary embodiments. 
         [0210]    While one or more exemplary embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.