Abstract:
The present disclosure relates to a sensor network, Machine Type Communication (MTC), Machine-to-Machine (M2M) communication, and technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the above technologies, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The present disclosure relates to a method and an apparatus for communication between devices in a wireless communication system, the method for communication of a terminal in a wireless communication system comprises the steps of: determining a resource section for communication between the terminal and an auxiliary device positioned within a critical distance; and performing the communication with the auxiliary device using the determined resource section, wherein the resource section may comprise at least one from among a waiting section which is unused for communication between terminals, a channel section which is occupied by another terminal, and a channel section which is occupied by a channel occupation request signal of the terminal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application is a U.S. National Stage application under 35 U.S.C. §371 of an International application filed on Sep. 23, 2015 and assigned application number PCT/KR2015/009986, which claimed the benefit of a Korean patent application filed on Sep. 24, 2014 in the Korean Intellectual Property Office and assigned Serial number 10-2014-0127709, the entire disclosure of which is hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to a method and an apparatus for communication between short-range devices in a wireless communication system. 
       BACKGROUND ART 
       [0003]    The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the Internet of Things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of the IoT technology and the Big Data processing technology through connection with a cloud server, has emerged. As technology elements, such as “sensing technology”, “wired/wireless communication and network infrastructure”, “service interface technology”, and “Security technology” have been demanded for IoT implementation, a sensor network, a Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and so forth have been recently researched. 
         [0004]    Such an IoT environment may provide intelligent Internet technology services that create a new value to human life by collecting and analyzing data generated among connected things. IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances and advanced medical services through convergence and combination between existing Information Technology (IT) and various industrial applications. 
         [0005]    Typically, in a wireless communication system, a device may perform a discovery and association procedure, and may be connected to and may communicate with another unspecified device located at a short range. For example, a 802.11 standard provides a communication scheme between devices located at a short range by using a contention-based wireless channel access scheme through a discovery and association procedure. That is, a particular terminal may access a wireless channel through contention with other devices located in a neighboring area, and thereby may ensure time resources for transmitting/receiving data to/from another device located at a short range. However, this scheme is disadvantageous in that a device needs to perform contention with multiple devices in order to access a wireless channel and thus, cannot stably communicate with a particular device. For example, in a situation where a particular device needs to transmit high-capacity data having very high QoS requirements to another device, when multiple devices located adjacent to the particular device desire to access a wireless channel, limited resources cause a ratio, at which the particular device is capable of using resources and other devices are capable of using resources, to become low. Accordingly, the particular device cannot seamlessly transmit high-capacity data to another device. The more the number of devices located at a short range becomes, the more remarkably the above-described degradation of the transmission performance of the device appears. 
       DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
       [0006]    Accordingly, an embodiment of the present disclosure provides a method and an apparatus for stable communication between devices located at a short range in a wireless communication system. 
         [0007]    Another embodiment of the present disclosure provides a method and an apparatus for causing a device to communicate with a particular predetermined device with low power in a wireless communication system. 
         [0008]    Still another embodiment of the present disclosure provides a method and an apparatus for causing a device to communicate with other devices and a predetermined device by using one modem chip in a wireless communication system. 
         [0009]    Yet another embodiment of the present disclosure provides a method and an apparatus for causing a device to determine resources for communicating with a particular predetermined device in a wireless communication system. 
         [0010]    Still yet another embodiment of the present disclosure provides a method and an apparatus for causing a device to divide a communication period into a first period and a second period, to communicate with other unspecified devices during the first period, and to communicate with a particular predetermined device during the second period in a wireless communication system. 
         [0011]    Further another embodiment of the present disclosure provides a method and an apparatus for designing an antenna in view of communication between particular devices and performing communication by using the designed antenna in a wireless communication system. 
       Technical Solution 
       [0012]    In accordance with an aspect of the present disclosure, a communication method of a mobile station in a wireless communication system is provided. The communication method may include determining a resource period for communication between the mobile station and a particular device located within a threshold distance; and communicating with the particular device by using the determined resource period, wherein the resource period may include at least one of a stand-by period which is unused for communication between mobile stations, a channel period that another mobile station is occupying, and a channel period occupied by a channel occupation request signal from the mobile station. 
         [0013]    In accordance with another aspect of the present disclosure, a communication apparatus of a mobile station in a wireless communication system is provided. The communication apparatus may include a controller configured to determine a resource period for communication between the mobile station and a particular device located within a threshold distance; and a communication unit configured to communicate with the particular device by using the determined resource period, wherein the resource period may include at least one of a stand-by period which is unused for communication between mobile stations, a channel period that another mobile station is occupying, and a channel period occupied by a channel occupation request signal from the mobile station. 
         [0014]    In accordance with still another aspect of the present disclosure, a communication method of a device in a wireless communication system is provided. The communication method may include receiving, from a particular mobile station, resource period allocation information for allocating a resource period; and communicating with the particular mobile station during the allocated resource period, wherein the allocated resource period may include at least one of a stand-by period which is unused for communication between mobile stations, a channel period that another mobile station is occupying, and a channel period occupied by a channel occupation request signal from the mobile station. 
         [0015]    In accordance with yet another aspect of the present disclosure, a communication apparatus of a device in a wireless communication system is provided. The communication apparatus may include a communication module configured to transmit/receive a signal to/from a particular mobile station; and a controller configured to receive resource period allocation information for allocating a resource period from the particular mobile station through the communication unit, and to perform a control operation for communicating with the particular mobile station during the allocated resource period, wherein the allocated resource period may include at least one of a stand-by period which is unused for communication between mobile stations, a channel period that another mobile station is occupying, and a channel period occupied by a channel occupation request signal from the mobile station. 
       Advantageous Effects 
       [0016]    In the present disclosure, in the wireless communication system, the device can communicate with the particular predetermined device with low power, and thereby can stably perform communication without interfering with a communication link of other devices located at a short range. Also, in the present disclosure, in the wireless communication system, the device can divide a communication period into a first period and a second period, can communicate with other unspecified devices during the first period, can communicate with a particular predetermined device during the second period, and thereby can communicate with a particular device while communicating with an unspecified device located at a short range by using one modem chip. Further, in the present disclosure, it is possible to obtain the effect that the device can communicate with a particular device located at a short range by using channel resources occupied by unspecified devices, and thereby can perform stable communication even when multiple devices desire to access a channel. Also, the present disclosure is advantageous in that overhead required to set a beam direction can be reduced by using an antenna designed in view of communication between particular devices. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a view illustrating a scheme in which a mobile station communicates with another mobile station and a cover according to an embodiment of the present disclosure; 
           [0018]      FIG. 2  is a view illustrating a procedure in which a mobile station determines communication resources between the mobile station and a cover according to an embodiment of the present disclosure; 
           [0019]      FIG. 3  is a view illustrating a procedure in which a mobile station passively determines communication resources through channel monitoring according to an embodiment of the present disclosure; 
           [0020]      FIG. 4  is a view illustrating a procedure in which a mobile station actively determines communication resources through channel monitoring according to an embodiment of the present disclosure; 
           [0021]      FIG. 5A  is a view illustrating a procedure in which a mobile station communicates with a cover according to an embodiment of the present disclosure; 
           [0022]      FIG. 5B  is a view illustrating a procedure in which a cover communicates with a mobile station according to an embodiment of the present disclosure; 
           [0023]      FIG. 5C  is a view illustrating a communication procedure between a mobile station and a cover according to an embodiment of the present disclosure; 
           [0024]      FIG. 5D  is a view illustrating a structure of a resource allocation message transmitted from a mobile station to a cover according to an embodiment of the present disclosure; 
           [0025]      FIG. 6A  is a view illustrating a procedure in which a mobile station changes a communication state of a cover according to an embodiment of the present disclosure; 
           [0026]      FIG. 6B  is a view illustrating a procedure in which a cover changes a communication state according to the control of a mobile station according to an embodiment of the present disclosure; 
           [0027]      FIG. 6C  is a view illustrating a structure of a communication state information message transmitted from a mobile station to a cover according to an embodiment of the present disclosure; 
           [0028]      FIG. 6D  is a view illustrating screen configurations of a mobile station and a cover according to an embodiment of the present disclosure; 
           [0029]      FIG. 7A  is a view illustrating a procedure in which a mobile station communicates with a cover by using a particular predetermined beam direction according to an embodiment of the present disclosure; 
           [0030]      FIG. 7B  is a view illustrating a beam direction between a mobile station and a cover according to an embodiment of the present disclosure; 
           [0031]      FIG. 7C  is a view illustrating a cover with an antenna according to an embodiment of the present disclosure. 
           [0032]      FIG. 8A  is a view illustrating the installation position of an antenna of each of a mobile station and a cover according to an embodiment of the present disclosure; 
           [0033]      FIG. 8B  is a view illustrating an example of a structure of an antenna of each of a mobile station and a cover according to an embodiment of the present disclosure; 
           [0034]      FIG. 8C  is a view illustrating another example of a structure of an antenna of each of a mobile station and a cover according to an embodiment of the present disclosure; 
           [0035]      FIG. 9  is a view illustrating a block configuration of a mobile station according to an embodiment of the present disclosure; and 
           [0036]      FIG. 10  is a view illustrating a block configuration of a cover according to an embodiment of the present disclosure. 
       
    
    
     MODE FOR CARRYING OUT THE DISCLOSURE 
       [0037]    Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. Also, in describing the present disclosure, a detailed description of related known configurations or functions incorporated herein will be omitted when it is determined that the detailed description thereof may unnecessarily obscure the subject matter of the present disclosure. Further, terms described below are defined in view of functions in the present disclosure, and can be different depending on user and operator&#39;s intention or practice. Therefore, the terms should be defined based on the disclosure throughout this specification. 
         [0038]    Hereinafter, some embodiments of this specification will be described in detail with reference to the exemplary drawings. It should be noted that in assigning reference numerals to elements in the drawings, the same reference numerals will designate the same elements where possible although they are shown in different drawings. Further, in the following description of embodiments of this specification, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of this specification rather unclear. 
         [0039]    In addition, terms, such as first, second, A, B, (a), (b), and the like, may be used herein when describing elements of this specification. These terms are merely used to distinguish one structural element from other structural elements, and a property, an order, a sequence, and the like of a corresponding structural element are not limited by the term. It will be understood that when an element is described as being “connected”, “linked”, or “coupled” to another element, the element can be directly connected or coupled to said another element but can be indirectly “connected”, “coupled”, or “linked” to said another element via a third element. 
         [0040]    A Mobile Station (MS) according to an embodiment of the present disclosure may be fixed or may have mobility, and may be referred to as a User Equipment (UE), a Mobile Terminal (MT), a User Terminal (UT), a Subscriber Station (SS), a wireless device, a Personal Digital Assistant (PDA), a wireless modem, a handheld device, a device, an electronic device, and the like. 
         [0041]    Hereinafter, in the description of the present disclosure, a method and an apparatus for stable communication between MSs in a wireless communication system will be described. Particularly, in embodiments of the present disclosure, a method and an apparatus for causing MSs located at a short range to stably communicate with each other will be described. Hereinafter, for convenience of description, although communication between an MS and a cover is described as an example, the embodiments of the present disclosure as described below may be similarly applied to communication between an MS and another MS or communication between an MS and an accessory device (or auxiliary device). In embodiments of the present disclosure, a cover is one of accessory devices that are used together with a portable device at a location adjacent to the portable device, and may include a wireless communication module. According to an embodiment of the present disclosure, accessory devices such as a cover may include a wireless communication module, and may additionally include a display apparatus and a memory. The accessory devices may be a cover, a flip cover, a protection case, an electronic pen, a mobile phone ring, an earphone, an earcap, and the like. 
         [0042]      FIG. 1  illustrates a scheme in which an MS communicates with another MS and a cover according to an embodiment of the present disclosure. 
         [0043]    As illustrated in  FIG. 1 , the MS  100  communicates with another MS  102  on the basis of a standard specification during a normal period  112 . For example, the MS  100  may discover another unspecified MS  102  around the MS  100  according to the 802.11 standard during the normal period  112 , may be connected to another discovered MS  102 , and may communicate (as indicated by reference numeral  110 ) with said another MS  102 . Also, according to an embodiment of the present disclosure, the MS  100  may communicate (as indicated by reference numeral  120 ) with a cover  104  located within a short range during a cover interval  122 . For example, the cover  104  may include a second display apparatus  106 , and may display graphic data, which is received from the MS  100 , on the second display apparatus  106 . In this case, the cover  104  may serve as an additional display device for the MS  100 . As another example, although not illustrated in  FIG. 1 , the cover  104  may include a memory, and may store data, which is received from the MS  100 , in the memory. In this case, the cover  104  may serve as an additional memory for the MS  100 . 
         [0044]    In an embodiment of the present disclosure, consideration is given to a case where the cover  104  only communicates with the predetermined MS  100 , and does not communicate with the MS  102  other than the predetermined MS  100 . Also, the MS  100  and the cover  104  are located at a very short range therebetween. Accordingly, in an embodiment of the present disclosure, the MS  100  communicates with the cover  104  by using very small power, and thereby, the communication between the MS  100  and the cover  104  does not interfere with the communication of another MS  102 . Here, power used for communication between the MS  100  and the cover  104  may be preset in a design phase through an experiment. 
         [0045]    In an embodiment of the present disclosure, in order to keep communication between the MS  100  and the cover  104  from affecting communication of another MS  102 , the cover  104  may be designed to configure a shielded space. For example, in order to keep an electrical signal exchanged for communication between the MS  100  and the cover  104  from escaping from the cover  104  and being delivered to the outside, the cover  104  may configure a shielded space for shielding an electrical signal. This configuration will be described in detail with reference to  FIGS. 8A to 8C . 
         [0046]    According to an embodiment of the present disclosure, the cover interval  122  is a period during which the MS  100  communicates with the cover  104 , and, may be configured as a period which is unused for communication between MSs or communication between an MS and a base station, or may be configured as a period which is passively or actively determined according to a channel occupation situation. For example, the cover interval  122  may include a period which is unused for communication between MSs, or communication between an MS and an Access Point (AP) or a base station, such as an Inter-Frame Space (IFS), a Short Inter-Frame Space (SIFS), a Distributed Inter-Frame Space (DIFS), a guard time period, and the like. Here, the IFS signifies a time interval during which multiple MSs stand by in order to avoid a case where, in a wireless communication network, the multiple MSs simultaneously access a wireless channel and collide with each other. The SIFS signifies a minimum IFS. Also, the DIFS signifies a time interval during which the MS needs to stand by from a time point at which another MS has lastly used the AP when the MS accesses the AP. Further, the cover interval  122  may be configured as a channel period occupied by another MS, or may be configured as a channel period occupied by the transmission of a channel occupation signal by the MS  100 . According to an embodiment of the present disclosure, the length and position of the cover interval  122  may be dynamically adjusted according to a service and a situation of a channel which are used by the cover. 
         [0047]    Also, according to an embodiment of the present disclosure, when the MS  100  includes one communication modem, the MS  100  communicates with the cover  104  during a period corresponding to the cover interval  122 , and thus, does not transmit/receive a packet to/from another neighboring MS. Accordingly, the MS  100  including the one communication modem may set an antenna beam direction so as to communicate with the cover  104  during the period corresponding to the cover interval  122 , and may perform dedicated communication with the cover  104 . 
         [0048]      FIG. 2  illustrates a procedure in which an MS determines communication resources between the MS and a cover according to an embodiment of the present disclosure. 
         [0049]    Referring to  FIG. 2 , in step  201 , the MS  100  checks whether a communication event with the cover  104  is detected. For example, the communication event with the cover  104  may be detected by a request of a user, the execution of a service which requires the communication with the cover  104 , or the like. As a more specific example, in a case where the user makes a request for display by the second display apparatus  106  included in the cover  104 , when an application is executed which performs a display through the second display apparatus  106  included in the cover  104 , when the user makes a request for storage in the memory included in the cover  104 , or when an application is executed which performs a storage in the memory included in the cover  104 , the MS  100  may detect that a communication event with the cover  104  has occurred. 
         [0050]    In step  203 , the MS  100  determines a period, that another MS  102  does not use, as a cover interval. For example, the MS  100  may determine a time period (e.g., IFS, SIFS, DIFS, or guard time period), during which the MS stands by without performing communication, in addition to a communication period  110  of the MS defined by a standard specification, as a cover interval. 
         [0051]    Then, in step  205 , the MS  100  checks whether additional resources are required. That is, the MS  100  checks whether additional resources are required in addition to the cover interval determined in step  203  in order to communicate with the cover  104 . For example, the MS  100  may determine whether the allocation of additional resources is required, on the basis of an application type which requests communication with the cover  104 , the amount of data to be transmitted/received to/from the cover  104 , the length of the cover interval, whether data to be transmitted/received to/from the cover  104  is likely to be delayed, and the like. When it is determined that the additional resources are not required, the MS  100  terminates the communication resource determination procedure according to an embodiment of the present disclosure. 
         [0052]    Meanwhile, when it is determined that the additional resources are required, in step  207 , the MS  100  monitors a channel, and determines whether the use of the channel is detected. For example, the MS  100  monitors a channel and checks whether a packet is received from another MS  102 . At this time, when the packet is received from said another MS  102 , the MS  100  may determine that the channel is being used. When the packet is not received from said another MS  102 , the MS  100  may determine that an MS which is using the channel does not exist. 
         [0053]    When it is determined that the channel is being used, the MS  100  proceeds to step  209  and checks whether a situation requires communication between the MS  100  and said another MS  102 . For example, the MS  100  acquires a destination address of the packet from a header of the relevant packet received from said another MS  102 , and determines whether a destination of the relevant packet is the MS  100  itself or still another MS, on the basis of the acquired destination address. When the destination address included in the received packet is identical to an address of the MS  100  itself, the MS  100  may determine that a situation requires communication between the MS  100  and said another MS  102  that has transmitted the received packet. In contrast, when the destination address included in the received packet is different from the address of the MS  100  itself, the MS  100  may detect a situation of communication between said another MS  102  and still another MS, and may determine that the situation does not require the communication between the MS  100  and said another MS  102 . 
         [0054]    When the situation requires the communication between the MS  100  and said another MS  102 , in step  211 , the MS  100  communicates with said another MS  102  according to a standard specification, and terminates the communication resource determination procedure according to an embodiment of the present disclosure. Thereafter, the MS  100  may again perform a communication resource determination procedure according to an embodiment of the present disclosure. Here, in a situation where a communication event with the cover  104  is detected, when a situation requiring the communication between the MS  100  and said another MS  102  is detected, the MS  100  may first perform communication, which has a higher priority, according to a preset priority. For example, the MS  100  may perform a control operation for first communicating with said another MS  102  and communicating with the cover  104  after the communication with said another MS  102  is terminated. As another example, the MS  100  may perform a control operation for first communicating with the cover  104  and communicating with said another MS  102 . At this time, the MS  100  may cause the display apparatus to provide a user interface that requests a setting of whether the MS  100  is to first communicate with one of the cover  104  and said another MS  102 . Also, the MS  100  may display a message or graphic data which indicates that the execution of communication with a particular device causes communication with another device to be delayed. 
         [0055]    Meanwhile, when it is determined as a result of the checking in step  207  that the channel is not being used, the MS  100  proceeds to step  215  in which the MS  100  occupies a channel period through contention and determines the occupied channel as a cover interval. For example, the MS  100  may transmit, to other neighboring MSs, Ready To Send (RTS)/Clear To Send (CTS) or self-CTS for occupying a channel, and may occupy a channel period for communicating with the cover  104 . Here, the RTS signal is a signal which notifies a reception-side MS that the MS desires to transmit data, and the CTS signal is a signal which allows the MS, that has received the RTS signal, to transmit data to a transmission-side MS. Also, the self-CTS signal signifies a signal that the MS, that has not received the RTS signal, transmits to neighboring MSs in order to occupy a channel. The MS  100  according to an embodiment of the present disclosure may include information on a required channel resource period in RTS or self-CTS, and may occupy the relevant channel resources. The MS  100  determines the cover interval, and then terminates the communication resource determination procedure according to an embodiment of the present disclosure. 
         [0056]    Meanwhile, when a result of the checking in step  209  shows that a situation does not require the communication between the MS  100  and said another MS  102 , in step  213 , the MS  100  determines a channel period, that other MSs use, as a cover interval. For example, the MS  100  may confirm channel occupation resources of other MSs from a received packet for communicating with the relevant other MSs, and may determine the confirmed channel occupation resources as a cover interval for communication between the MS and the cover. Here, the MS  100  may acquire information on a channel period, during which the relevant other MSs perform communication, from a channel occupation period field included in a header of the received packet, may set a timer corresponding to the acquired information on the channel period, and may determine an operating period of the timer as a cover interval. Here, the reason why channel resources (e.g., a time period) that the other MSs occupy is determined as a cover interval is because power for communication between the MS  100  and the cover  104  is small enough not to interfere with other neighboring MSs. The MS  100  determines the cover interval, and then terminates the communication resource determination procedure according to an embodiment of the present disclosure. 
         [0057]      FIG. 3  illustrates a procedure in which an MS passively determines communication resources through channel monitoring according to an embodiment of the present disclosure. 
         [0058]    As illustrated in  FIG. 3 , the MS  100  detects a packet through channel monitoring in step  301 , and confirms a destination address of the packet detected through the channel monitoring in step  303 . In step  305 , the MS  100  checks whether the destination address of the detected packet is an address of the MS itself. When the destination address of the detected packet is the address of the MS itself, in step  315 , the MS  100  receives a header of the packet, and then, continuously receives and decodes a payload of the packet. That is, when the destination address included in the header of the detected packet is identical to the address of the MS itself, the MS  100  may additionally receive a payload which follows the header of the relevant packet, and may communicate with said another MS  102 , that has transmitted the relevant packet, according to a standard specification. Thereafter, the MS  100  terminates the passive communication resource determination procedure according to an embodiment of the present disclosure. Here, the MS, that has terminated the passive communication resource determination procedure, may again perform a passive communication resource determination procedure or may perform an active communication resource determination procedure. 
         [0059]    In contrast, when the destination address of the detected packet is not the address of the MS itself, in step  307 , the MS  100  allocates a period, which corresponds to a period of the detected packet, as a cover interval. For example, the MS  100  may confirm information on a channel period included in the header of the detected packet, and may determine the confirmed channel period as a cover interval. Here, since a result of monitoring the channel shows that a packet of which the destination is the MS  100  is not received, the MS  100  may recognize that a packet, that the MS  100  needs to receive from said another MS  102 , does not exist during the relevant channel period. The MS  100  may perform data communication with the cover during the allocated cover interval, in step  309 , and checks whether additional resources are required, in step  311 . For example, the MS  100  may determine whether additional resources are required, on the basis of communication throughput between the MS  100  and the cover  104 . Also, the MS  100  may determine whether a situation requires additional resources, on the basis of the amount of data transmitted/received between the MS  100  and the cover  104  and a period corresponding to the allocated cover interval. When it is determined that the additional resources are not required, the MS  100  terminates the passive communication resource determination procedure according to an embodiment of the present disclosure. 
         [0060]    In contrast, when it is determined that the additional resources are required, the MS  100  proceeds to step  313  in which the MS  100  occupies a channel period through contention and allocates the occupied channel period as a cover interval. Here, a configuration in which the MS  100  occupies a channel period through contention and allocates the occupied channel period as a cover interval may be performed in a scheme similar to that of steps  403  to  405  of  FIG. 4  below. Thereafter, the MS  100  terminates the passive communication resource determination procedure according to an embodiment of the present disclosure. 
         [0061]      FIG. 4  illustrates a procedure in which an MS actively determines communication resources through channel monitoring according to an embodiment of the present disclosure. 
         [0062]    Referring to  FIG. 4 , in step  401 , the MS  100  detects a situation in which a channel is not occupied, through channel monitoring. For example, when no packet is received through channel monitoring, the MS  100  may confirm that another MS that is connected to a channel or desires to access the channel does not exist, and may determine that said another MS does not occupy the channel. 
         [0063]    In step  403 , the MS  100  transmits a channel occupation signal, which includes a particular period value, to other neighboring MSs. For example, the MS may transmit an RTS signal or a self-CTS signal, which includes information on a channel period to be used to communicate with the cover, to other neighboring MSs. The other neighboring MSs, that have received the RTS signal or the self-CTS signal from the MS  100 , recognize that the relevant MS is performing communication during a relevant channel period, and do not attempt to communicate with the MS during the relevant channel period. 
         [0064]    Thereafter, the MS  100  proceeds to step  405 , and allocates a particular period, which corresponds to the particular period value included in the channel occupation signal, as a cover interval. Then, the MS  100  proceeds to step  407  in which the MS  100  performs data communication with the cover  104  during a period corresponding to the allocated cover interval. Then, the MS  100  terminates the active communication resource determination procedure according to an embodiment of the present disclosure. 
         [0065]      FIG. 5A  illustrates a procedure in which an MS communicates with a cover according to an embodiment of the present disclosure. 
         [0066]    Referring to  FIG. 5A , the MS  100  detects that data to be transmitted from the cover  104  to the MS  100  exists in step  501 , and determines a cover interval in step  503 . For example, the cover  104  according to an embodiment of the present disclosure communicates with only a predetermined MS or an MS located within a threshold distance, and thus has difficulty in autonomously acquiring resources. Accordingly, in an embodiment of the present disclosure, the MS  100  detects a case where data to be transmitted from the cover  104  to the MS  100  exists, and determines a cover interval for communicating with the cover  104 . For example, at a preset time point or when a particular application is executed, the MS  100  may detect a particular event or may receive a request signal from the cover  104  during a preset period, and may confirm that data to be transmitted from the cover  104  to the MS  100  exists. Also, as illustrated in  FIGS. 2 to 4 , the MS  100  may determine a period, that said another MS  102  does not use, as a cover interval, or may determine a cover interval on the basis of a passive communication resource determination scheme or an active communication resource determination scheme. 
         [0067]    In step  505 , the MS  100  transmits a data transmission request signal, which includes cover interval information, to the cover  104 . According to an embodiment of the present disclosure, the data transmission request signal including cover interval information may be configured as illustrated in  FIG. 5D . For example, the data transmission request signal including cover interval information may include element identification information (element ID)  530  representing cover identification information, length information  532  of a message, the number of allocated cover intervals (number of allocations)  534 , time offsets (time offset #N)  536 - 1  and  536 - 2  representing start points of respective cover intervals, periods (cover interval duration #N)  538 - 1  and  538 - 2  of the respective cover intervals, and pieces of transmission direction information (direction info #N)  540 - 1  and  540 - 2  of the respective cover intervals. Here, when a cover interval period is not continuous and includes divided time periods, the number of allocated cover intervals may represent the number of the divided time periods. For example, when cover intervals are a period of 0 to 5 seconds, a period of 30 to 40 seconds, a period of 45 to 50 seconds, the number of cover intervals may be represented as being three. Also, a time offset, an interval period, and transmission direction information signifies information may be repeatedly included by the number of cover intervals. Further, here, the transmission direction information signifies information which indicates a period during which the MS  100  transmits a signal to the cover  104  or a period during which the cover  104  transmits a signal to the MS  100 . 
         [0068]    Thereafter, in step  507 , the MS  100  receives data from the cover  104  during the cover interval period. Then, the MS  100  may terminate the communication procedure with the cover according to an embodiment of the present disclosure. 
         [0069]      FIG. 5B  illustrates a procedure in which a cover communicates with an MS according to an embodiment of the present disclosure. 
         [0070]    Referring to  FIG. 5B , in step  511 , the cover  104  receives a data transmission request signal, which includes cover interval information, from the MS  100 . According to an embodiment of the present disclosure, the data transmission request signal may be configured as illustrated in  FIG. 5D . Thereafter, the cover  104  acquires the cover interval information from the data transmission request signal in step  513 , and transmits data to the MS  100  during a cover interval period in step  515 . 
         [0071]      FIG. 5C  illustrates a communication procedure between an MS and a cover according to an embodiment of the present disclosure. 
         [0072]    Referring to  FIG. 5C , the MS  100  detects the existence of data that the cover  104  is to transmit to the MS  100 , and monitors a channel in order to allocate a cover interval in step  520 . Then, in step  522 , the MS  100  acquires cover interval information through passive resource allocation or active resource allocation on the basis of a result of monitoring the channel. For example, the MS  100  may confirm a channel period used for communication between said another MS  102  and still another MS, from a packet that said another MS  102  located adjacent to the MS  100  has transmitted, and may allocate the confirmed channel period as a cover interval. As another example, when the MS  100  does not receive a packet from said another MS  102  located adjacent to the MS  100 , the MS  100  may detect that an MS that occupies a channel does not exist, may transmit an RTS or self-CTS signal and may occupy a channel period, and may allocate the occupied channel period as a cover interval. 
         [0073]    Then, in step  524 , the MS  100  may transmit a data transmission request signal, which includes cover interval information, to the cover  104 . According to an embodiment of the present disclosure, the data transmission request signal including cover interval information may be configured as illustrated in  FIG. 5D . Thereafter, the MS  100  may receive data from the cover  104  during a cover interval period in step  526 , and may transmit an ACK message, which notifies of the successful reception of the data, to the cover  104  in step  528 . 
         [0074]    The description has been made in view of the case where the cover  104  transmits data to the MS  100  with reference to  FIGS. 5A to 5D . However, the above-described embodiment of the present disclosure may be similarly applied to a case where the MS  100  transmits data to the cover  104 . For example, when the MS  100  desires to transmit data to the cover  104 , the MS  100  may monitor a channel and may acquire a cover interval, and may transmit information on the cover interval to the cover  104 . 
         [0075]    Also, the acquisition of a cover interval through channel monitoring has been described with reference to  FIGS. 5A to 5D . However, the MS  100  may determine a period (e.g., IFS, SIFS, DIFS, guard time period, or the like), that said another MS  102  does not use for communication, as a cover interval without monitoring a channel, and may transmit information on the determined cover interval to the cover  104 . 
         [0076]      FIG. 6A  illustrates a procedure in which an MS changes a communication state of a cover according to an embodiment of the present disclosure. 
         [0077]    Referring to  FIG. 6A , in step  601 , the MS  100  checks whether a cover communication interruption event is detected. For example, the cover communication interruption event may be generated by a user input. For example, while the MS  100  reproduces an image through the display apparatus included in the cover, the MS  100  may detect the selection of a menu by a user, the execution of a gesture by the user, or the input of a touch by the user which are for interrupting communication between the MS  100  and the cover  104 . As a specific example, the MS  100  may display a message which inquires of the user about whether the user is to interrupt the cover image reproduction as illustrated in  FIG. 6D , or may display an icon for controlling (e.g., interrupting or restarting) the cover image reproduction, and may receive an input for interrupting the cover image reproduction from the user. As another example, the MS  100  may detect a cover communication interruption event on the basis of the battery residual quantity of the MS  100 , the battery residual quantity of the cover  104 , and whether data exists. As a specific example, when the battery residual quantity of the MS  100  or the battery residual quantity of the cover  104  is less than a threshold, the MS  100  may detect may detect the occurrence of the cover communication interruption event. Here, the MS  100  may receive information on battery residual quantity from the cover  104  while communicating with the cover  104 , or may include a separate means that detects the battery residual quantity of the cover  104 . 
         [0078]    When the cover communication interruption event has been detected, the MS  100  proceeds to step  603  in which the MS  100  determines a sleep duration and an awake duration. Here, the sleep duration is a period during which a communication module of the cover  104  is turned off, and the awake duration is a period during which the communication module of the cover  104  is turned on. According to an embodiment of the present disclosure, the sleep duration and the awake duration may be predetermined. Then, in step  605 , the MS  100  transmits, to the cover  104 , information on the sleep duration and the awake duration. At this time, a signal for transmitting the information on the sleep duration and the awake duration may be configured as illustrated in  FIG. 6C . For example, a message for transmitting the information on the sleep duration and the awake duration may include element identification information (element ID)  630  representing cover identification information, length information  632  of the relevant message, information on a sleeping duration  634  and an awake duration  636 . 
         [0079]      FIG. 6B  illustrates a procedure in which a cover changes a communication state according to the control of an MS according to an embodiment of the present disclosure. 
         [0080]    Referring to  FIG. 6B , in step  611 , the cover  104  receives, from the MS  100 , information on a sleep duration and an awake duration. For example, the cover  104  may receive a message illustrated in  FIG. 6C , and may acquire information on a sleep duration and an awake duration, from the received message. 
         [0081]    In step  613 , the cover  104  determines whether a current time point corresponds to the sleep duration. When the current time point corresponds to the sleep duration, the cover  104  proceeds to step  617  in which the cover  104  turns off power of the communication module included in the cover  104 , and performs step  615 . For example, the cover  104  may determine that a signal is not received from the MS  100  during the sleep duration, and may turn off power of the communication module in order to reduce power consumption during the sleep duration. 
         [0082]    In contrast, when the current time point does not correspond to the sleep duration, the cover  104  proceeds to step  615  in which the cover  104  checks whether the current time point corresponds to the awake duration. When the current time point does not correspond to the awake duration, the cover  104  returns to step  613  in which the cover  104  may re-check whether the current time point corresponds to the sleep duration. 
         [0083]    When the current time point corresponds to the awake duration, the cover  104  proceeds to step  619  in which the cover  104  turns on power of the communication module included therein. For example, the cover  104  may determine that a signal is likely to be received from the MS  100  during the awake duration, and may turn on power of the communication module in order to detect the reception of a signal from the MS  100  during the awake duration. 
         [0084]    Then, in step  621 , the cover  104  checks whether a signal is received from the MS  100 . When the signal is not received from the MS  100 , the cover  104  returns to step  613 , and again performs the steps after step  613 . In contrast, when the signal is received from the MS  100 , in step  623 , the cover  104  may maintain the power-on state of the communication module and may communicate with the MS  100 . At this time, the cover  104  may acquire cover interval information from the MS  100 , and may transmit or receive data during a cover interval period. 
         [0085]    In step  625 , the cover  104  checks whether the communication with the MS  100  has been terminated. When the communication with the MS  100  has not been terminated, the cover  104  may return to step  623 , and may again perform the steps after step  623 . When the communication with the MS  100  has been terminated, the cover  104  may return to step  613 , and may again perform the steps after step  613 . 
         [0086]      FIG. 7A  illustrates a procedure in which an MS communicates with a cover by using a particular predetermined beam direction according to an embodiment of the present disclosure. 
         [0087]    Referring to  FIG. 7A , in step  701 , the MS  100  checks whether a current time point corresponds to a cover interval period. When the current time point corresponds to the cover interval period, in step  703 , the MS  100  switches to a non-standard channel access mode. For example, the MS  100  may not switch to a mode for communicating with said another MS  102  according to a standard specification during the cover interval period, but may switch to a mode for communicating with the cover  104  according to a non-standard specification. 
         [0088]    The MS  100  may set an antenna and beam direction to a preset cover communication direction in step  705 , and may transmit/receive data during an allocated cover interval period without a channel monitoring procedure in step  707 . For example, as illustrated in  FIG. 7B , the MS  100  may set an antenna beam direction of the MS  100  so as to face a direction in which the cover  104  is located. As another example, as illustrated in  FIG. 7C , the cover  104  may include an antenna  721  in an inner face that contacts a particular face of the MS  100 . In this case, the MS  100  may set an antenna beam direction to the direction of the particular face which contacts the cover  104 . Also, when the cover  104  includes the antenna  721  in the inner face that contacts the particular face of the MS  100  as illustrated in  FIG. 7C , a rear face of the cover  104  may be designed to include an element that shields a radio wave, so as to radiate a radio wave from the antenna  721  to only the particular face of the MS  100 . According to an embodiment of the present disclosure, the antenna beam direction of the MS  100  which faces a direction in which the cover  104  is located may be preset in a design stage in view of the antenna of the cover  104 , or may be set on the basis of information previously acquired from the cover  104 . Also, according to an embodiment of the present disclosure, an antenna beam direction of the cover  104  may be fixed so as to face a face, which contacts the MS  100 , without being changed. 
         [0089]      FIG. 8A  illustrates the installation position of an antenna of each of an MS and a cover according to an embodiment of the present disclosure.  FIGS. 8B and 8C  illustrate examples of a structure of the antenna of each of the MS and the cover according to an embodiment of the present disclosure. 
         [0090]      FIGS. 8A to 8C  illustrate an antenna design structure for minimizing an effect that a communication signal between the MS  100  and the cover  104  exerts on communication of other MSs. 
         [0091]    According to an embodiment of the present disclosure, the antenna  801  of the cover  104  and the antenna  803  of the MS  100  may be installed at locations illustrated in  FIG. 8A . That is, the antenna  801  of the cover  104  may be mounted at a location adjacent to the MS  100 , and the antenna  803  of the MS  100  may be mounted at a location adjacent to the antenna  801  of the cover  104 . At this time, the antenna  803  of the MS  100  may be a dedicated antenna for cover communication, or may be an antenna used for both the cover communication and communication with another MS. 
         [0092]    Also, according to an embodiment of the present disclosure, an antenna for communication of each of the cover  104  and the MS  100  may include radiators  811 ,  812  and  813 , and a shielding body  814  as illustrated in  FIG. 8B , or may include the radiators  811 ,  812  and  813 , and a cavity  815  as illustrated in  FIG. 8C . The radiator according to an embodiment of the present disclosure may be configured in a meandering pattern, and the size of the radiator may be configured such that the maximum length of a polygon or a circle including the radiator satisfies Equation 1. Here, the polygon or circle including the radiator may include a partial area of a substrate  821 . 
         [0000]    
       
         
           
             
               
                 
                   D 
                    
                   
                     
                       
                         λ 
                          
                         
                             
                         
                          
                         P 
                       
                       2 
                     
                   
                 
               
               
                 
                   Equation 
                    
                   
                       
                   
                    
                   1 
                 
               
             
           
         
       
     
         [0093]    Here, D represents the maximum length of the polygon or circle including the radiator, λ represents the length of a wavelength according to a frequency, and P represents a distance between the antenna of the MS  100  and the antenna of the cover  104 . For example, when the antenna of the MS  100  and the antenna of the cover  104  are designed as illustrated in  FIG. 8A , P may represent a distance between the MS and the cover, and is conventionally equal to about 20 mm. Equation 1 is for causing the antennas used for communication between the MS  100  and the cover  104  to operate in a near-field area. Here, the meandering pattern signifies that a conductive wire is bent and has a crank shape as in the first radiator  811  and the second radiator  812  illustrated in  FIGS. 8B and 8C . 
         [0094]    Also, as illustrated at the right of  FIG. 8B , the shielding body  814  according to an embodiment of the present disclosure may be formed of a metallic material having a mesh structure. At this time, a distance between the metallic material elements due to the mesh structure may be designed to be shorter than λ/8. This configuration is for shielding a radio wave radiated from the radiator. As illustrated in  FIG. 8B , according to an embodiment of the present disclosure, the antenna that includes the radiators  811 ,  812  and  813 , and the shielding body  814  may include the substrate  821 . For example, as illustrated in the side view of  FIG. 8B , the radiators  811 ,  812 , and  813  may be designed on one surface of the substrate  821 , and the shielding body  814  may be designed on the other surface of the substrate  821 . 
         [0095]    Further, the cavity  815  according to an embodiment of the present disclosure may be formed of a conductive material as illustrated at the right of  FIG. 8C . At this time, the height of the cavity  815  may be designed to be less than λ/4. Also, as illustrated in  FIG. 8C , according to an embodiment of the present disclosure, the antenna that includes the radiators  811 ,  812 , or  813 , and the cavity  815  may include the substrate  821 . For example, as illustrated in the side view of  FIG. 8C , the radiators  811 ,  812 , and  813  may be designed on one surface of the substrate  821 , and the remaining three surfaces may be shielding-processed as the cavity  815 . 
         [0096]      FIG. 9  illustrates a block configuration of an MS according to an embodiment of the present disclosure. 
         [0097]    Referring to  FIG. 9 , the MS  100  may include a controller  900 , a communication unit  910 , an antenna  920 , a storage unit  930 , an input unit  940 , and an output unit  950 . 
         [0098]    The controller  900  controls and processes an overall function of operating the MS  100 . For example, the controller  900  controls a function of communicating with another unspecified MS located around the MS  100 , and controls and processes a function of communicating with a particular device such as the cover  104 . For example, the controller  900  includes a cover communication controller  902 ; and determines a cover interval for communicating with the cover  104 , and controls and processes a function of communicating with the cover  104  on the basis of the cover interval. The cover communication controller  902  may determine a period (e.g., IFS, SIFS, DIFS, or guard time period), that other MSs do not use, as a cover interval according to a standard specification, and may determine a channel period, that other MSs occupy, as a cover interval. Also, the cover communication controller  902  may occupy a channel period through the transmission of a signal for occupying a channel, and may determine the occupied channel period as a cover interval. Also, the cover communication controller  902  may control and process a function of transmitting information on the cover interval to the cover  104 , may determine a sleep duration and an awake duration of the cover  104  in order to control a communication state of the cover  104 , and may control and process a function of transmitting, to the cover  104 , information on the determined sleep duration and awake duration. Further, the cover communication controller  902  controls and processes a function of adjusting the antenna  920  and/or a transmission/reception beam direction in order to communicate with the cover  104 . 
         [0099]    The communication unit  910  communicates with another MS, a base station, or the cover  104 , that is located around the MS  100 , according to the control of the controller  900 . For example, the communication unit  910  may include one communication modem. Particularly, according to the control of the controller  900 , the communication unit  910  may transmit/receive data to/from the cover  104  with preset low power during a cover interval. Also, the communication unit  910  may adjust the direction of the antenna  920  and/or a transmission/reception beam direction thereof in order to communicate with the cover  104  according to the control of the controller  900 . According to an embodiment of the present disclosure, the antenna  920  may be a beam antenna or an antenna array that is capable of forming a beam in a particular beam direction. As another example, the antenna  920  may include the radiators  811 ,  812  and  813 , and the shielding body  814  as illustrated in  FIG. 8B , or may include the radiators  811 ,  812  and  813 , and the cavity  815  as illustrated in  FIG. 8C . 
         [0100]    The storage unit  930  stores various data and programs for an overall operation of the MS  100 . According to an embodiment of the present disclosure, the storage unit  930  may store information on a cover interval, and may store information on a sleep duration and an awake duration. Also, the storage unit  930  may include information on power used to communicate with the cover  104 . 
         [0101]    The input unit  940  delivers a command or data, which is generated by a selection or gesture made by a user, to the controller  900 . For example, the input unit  940  may include at least one of at least one physical key button, a physical key pad, a touch detection sensor, a proximity sensor, an acceleration sensor, a microphone, and a mouse. 
         [0102]    The output unit  950  may output picture data, image data, or voice data to the user. For example, the output unit  950  may include a display apparatus that displays picture data or image data, and a speaker that outputs voice data. The display apparatus according to an embodiment of the present disclosure may display a graphic element representing communication with the cover  104 , or a graphic element representing the interruption of communication with the cover  104 . 
         [0103]      FIG. 10  illustrates a block configuration of a cover according to an embodiment of the present disclosure. 
         [0104]    Referring to  FIG. 10 , the cover  104  may include a controller  1000 , a communication unit  1010 , an antenna  1020 , a storage unit  1030 , an input unit  1040 , and an output unit  1050 . 
         [0105]    The controller  1000  controls and processes an overall function of operating the cover  104 . For example, the controller  1000  controls and processes a function of outputting data, which is received from the MS  100 , through the output unit  1050 , or a function of storing data, which is received from the MS  100 , in the storage unit  1030 . For example, an MS communication controller  1002  controls and processes a function of receiving, from the MS  100 , cover interval information for communicating with the MS  100 , and a function of communicating with the MS  100  on the basis of a cover interval. The MS communication controller  1002  controls a function of receiving, from the MS  100 , information on a sleep duration and an awake duration of the cover  104 , a function of turning off power of a communication module included in the communication unit  1010  during the sleep duration, and a function of turning on power of the communication module during the awake duration. 
         [0106]    The communication unit  1010  communicates with the particular preset MS  100  according to the control of the controller  1000 . For example, according to the control of the controller  1000 , the communication unit  1010  may transmit/receive data to/from the particular MS  100  with preset low power during a cover interval. 
         [0107]    The antenna  1020  may be a beam antenna or an antenna array that is capable of forming a beam in a particular beam direction. As another example, the antenna  1020  may include the radiators  811 ,  812  and  813 , and the shielding body  814  as illustrated in  FIG. 8B , or may include the radiators  811 ,  812  and  813 , and the cavity  815  as illustrated in  FIG. 8C . 
         [0108]    The storage unit  1030  stores various data and programs for communicating with the MS  100 . According to an embodiment of the present disclosure, the storage unit  1030  may store information on a cover interval, and may store information on a sleep duration and an awake duration. Also, the storage unit  1030  may include information on power used for communication between the cover  104  and the MS  100 . Further, the storage unit  1030  may store data received from the MS  100 . 
         [0109]    The input unit  1040  delivers a command or data, which is generated by a selection or gesture made by the user, to the controller  1000 . For example, the input unit  1040  may include at least one of at least one physical key button, a physical key pad, a touch detection sensor, a proximity sensor, an acceleration sensor, a microphone, and a mouse. 
         [0110]    The output unit  1050  may output picture data, image data, or voice data to the user. For example, the output unit  1050  may include a display apparatus that displays picture data or image data, or a speaker that outputs voice data. The display apparatus according to an embodiment of the present disclosure may display a graphic element corresponding to data received from the MS  100 . 
         [0111]    Although the present disclosure has been described with reference to the limited embodiments and the drawings as described above, the present disclosure is not limited to the above-described embodiments, and those having ordinary knowledge in the technical field, to which the present disclosure pertains, will appreciate that various modifications and changes in form may be made from the description. 
         [0112]    The operations according to embodiments of the present disclosure may be implemented by a single controller. In this case, program instructions for performing operations implemented by various computers may be recorded in a computer-readable medium. The computer-readable medium may include a program instruction, a data file, a data structure, and the like, alone or in a combination thereof. The program instructions may be especially designed and configured for the present disclosure, or may be known to and used by those skilled in the art. Examples of the computer-readable recording medium may include a magnetic medium such as a hard disk, a floppy disk, and a magnetic tape; an optical recording medium such as a Compact Disk Read Only Memory (CD-ROM) or a Digital Versatile Disk (DVD); a magneto-optical medium such as a floptical disk; and a hardware device specially configured to store and execute program instructions, such as a ROM, a Random Access Memory (RAM), a flash memory, and the like. Examples of the program instructions include a high-level language code, that a computer can execute by using an interpreter and the like, as well as a machine language code made by a compiler. When all or some of the base stations or relays as described in the present disclosure are implemented by a computer program, a computer-readable recording medium in which the computer program is stored also falls within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be defined as being limited to the described embodiments, but should be defined by the appended claims and equivalents thereof.