Patent Publication Number: US-2016249294-A1

Title: Method of controlling terminal and terminal employing the method

Description:
PRIORITY 
     This application claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2015-0026752, filed on Feb. 25, 2015 in the Korean Intellectual Property Office, the contents of which are incorporated herein by reference. 
     BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The present disclosure relates generally to a method of controlling a terminal, and more particularly, to method of controlling a terminal whereby power efficiency of the terminal may be enhanced. 
     2. Description of the Related Art 
     As the market for the Internet of Things (IoT) continues to grow, research on methods for bidirectional communication between a plurality of terminals has been actively conducted. In particular, there has been an attempt to perform various methods for communication between devices with no conventional Internet access capabilities. 
     Internet connection for devices not having Internet access capabilities requires the installation of modems, which is costly and time consuming. Accordingly, extensive research has been conducted on the use of tethering instead of modems. Tethering allows sharing an Internet connection of a tethered terminal having Internet connection capability and enables devices to access the Internet through the tethered terminal. 
     However, when one or more additional terminals are connected to the Internet by using the tethering feature of a terminal, power consumption of the terminal offered for tethering may suddenly increase. 
     As such, there is a need in the art for a method of controlling power consumption when the tethering feature is implemented. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure has been made to address the above-mentioned problems and disadvantages, and to provide at least the advantages described below. Accordingly, an aspect of the present disclosure is to provide a method of controlling a terminal, whereby power efficiency of the terminal may be enhanced by predicting a condition of the terminal from context information collected in the terminal and adaptively changing resources used for communication according to the predicted condition. 
     According to an aspect of the present disclosure, a method of controlling a terminal includes acquiring context information related to a location of the terminal, determining the location of the terminal by comparing acquired context information and patterns information related to a target location previously set, and determining at least one of transmission power and a scan period for communication between the terminal and another terminal according to characteristics of the determined location. 
     According to another aspect of the present disclosure, a terminal includes a context information acquirer that acquires context information related to a location of the terminal, a position determiner that determines the location of the terminal by comparing acquired context information and patterns information related to a target location previously set, and a controller that determines at least one of transmission power and a scan period for communication between the terminal and another terminal according to characteristics of the determined location. 
     According to another aspect of the present disclosure, a non-transitory computer-readable storage medium is disclosed having stored therein program instructions which, when executed by a computer, perform the method of controlling a terminal, including acquiring context information related to a location of the terminal, determining the location of the terminal by comparing acquired context information and patterns information related to a target location previously set, and determining at least one of transmission power and a scan period for communication between the terminal and another terminal according to characteristics of the determined location. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects, features, and advantages of the present disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  illustrates a method of controlling a terminal in accordance with an embodiment of the present disclosure; 
         FIG. 2  is a flowchart of a method of controlling a terminal in accordance with an embodiment of the present disclosure; 
         FIG. 3  is a flowchart of a method used by a terminal to determine at least one of transmission power and a scan period according to characteristics of a terminal location determined based on information detected from surroundings of the terminal in accordance with an embodiment of the present disclosure; 
         FIG. 4  is a flowchart of a method used by a terminal to determine at least one of transmission power and a scan period according to characteristics of a terminal location determined based on history information of connections between the terminal and another device at a target location in accordance with an embodiment of the present disclosure; 
         FIG. 5  illustrates a method of determining at least one of transmission power and a scan period according to characteristics of terminal location determined based on the connection of a terminal and another device at a target location in accordance with an embodiment of the present disclosure; 
         FIGS. 6A and 6B  illustrate a method of determining transmission power based on types of vehicles in accordance with an embodiment of the present disclosure; 
         FIGS. 7A and 7B  illustrate a method of determining scan periods for other terminals according to characteristics of a location of a terminal in accordance with an embodiment of the present disclosure; 
         FIG. 8  is a flowchart of a method used by a terminal to acquire context information in a predetermined interval and update the information related to a location of the terminal in accordance with an embodiment of the present disclosure; 
         FIG. 9  is a flowchart of a method used by a terminal according to an embodiment to transmit information of at least one of transmission power and a scan period to another terminal at a target location when the terminal is located at the target location in accordance with an embodiment of the present disclosure; 
         FIG. 10  illustrates a method used by a terminal according to an embodiment to transmit information of at least one of transmission power and a scan period to another terminal at a target location when the terminal is located at the target location in accordance with an embodiment of the present disclosure; and 
         FIGS. 11 and 12  are block diagrams of a terminal according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE DISCLOSURE 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present disclosure. In describing the present disclosure below, a detailed description of related known configurations or functions incorporated herein will be omitted for the sake of clarity and conciseness. 
     It will be understood that when an element is referred to as being “connected to” another element, it can be “directly connected to” the other element or “electrically connected to” the other element. The terms “comprises” and/or “comprising” or “includes” and/or “including” or “contains” and/or “containing” when used in this specification, specify the presence of stated elements, but do not preclude the presence or addition of one or more other elements. 
       FIG. 1  illustrates a method of controlling a terminal  100  according to an embodiment of the present disclosure. 
     Referring to  FIG. 1 , the terminal  100  may be used for tethering so that the terminal  100  may operate as a wireless modem. The terminal  100  permits one or more information technology (IT) devices to be connected thereto via universal serial bus (USB), Bluetooth™, or WiFi connection. The IT devices connected to the terminal  100  may access the Internet via tethered wireless connection through the terminal  100 . The IT devices include a smartphone, a notebook computer, a tablet personal computer (PC), a vehicle, and a wearable device in various embodiments, but are not limited thereto. 
     A vehicle  5  will be described in the specification as an example of IT devices that may be tethered to the terminal  100 . 
     When the terminal  100  is offered for the tethering, the terminal  100  checks for the presence of connectable IT devices. For example, the terminal  100  transmits a beacon frame based on predetermined scan period and transmission power. The terminal  100  determines the connectable IT devices based on the presence of IT devices responding to the beacon frame. Hereinbelow, the IT devices that may be tethered to the terminal  100  are referred to as “another” terminals, “other” terminals, or “the other” terminals. 
     The terminal  100  determines at least one of the transmission power and the scan period for transmitting frames to search other terminals depending on the location of the terminal  100 . For example, when the terminal  100  is located in the vehicle  5 , the space inside the vehicle  4  may be limited. When the vehicle  5  is in motion, another terminal in the vehicle  5  moves with the terminal  100 . Thus, the terminal in the vehicle  5  may use the wireless Internet without continuously performing scans for searching another access point (AP). 
     The terminal  100  controls the transmission power and the scan period for searching other terminals to be tethered, by using distinct characteristics of the vehicle inside. For example, the terminal  100  increases the scan period while lowering the transmission power if a current location is identified as being inside of a vehicle. 
     The terminal  100  acquires context information representing the location of the terminal  100 . The context information includes acceleration information of the terminal  100 , atmospheric pressure and sound information of surroundings, history information of the terminal  100  about connections with other terminals in a particular location. The terminal  100  compares acquired context information with patterns information representing target location set previously, and determines the location of the terminal  100 . As the location of the terminal  100  is determined, the terminal  100  determines characteristics of the location of the terminal  100  based on characteristics of the target location stored previously in a database. 
     For example, as a user  10  moves in  FIG. 1 , the location of the terminal  100  changes from inside to outside of the vehicle  5 . The terminal  100  determines at least one of the transmission power and the scan period for searching other terminals inside the vehicle  5  depending on characteristics of the vehicle  5 . 
     The terminal  100  enhances power efficiency by determining at least one of the transmission power and the scan period for searching other terminals depending on characteristics of the location of the terminal  100 . 
     When the terminal  100  is provided with the tethering service by another terminal, the terminal  100  controls the transmission power for transmitting frames to the other terminal depending on the characteristics of the location of the terminal  100 , which is described below in detail with reference to  FIG. 7 . 
     The terminals  100  include, but are not limited to a wearable device, a WiFi enabled device, a Bluetooth™ appcessory, a tablet PC, a smartphone, a WiFi router. 
       FIG. 2  is a flowchart explaining a method for controlling the terminal  100  in accordance with an embodiment of the present disclosure. 
     In step S 210 , the terminal  100  acquires context information representing the location of the terminal  100 . 
     The context information includes acceleration information of the terminal  100 , and atmospheric pressure and sound information of surroundings of the terminal  100 . For example, when the terminal  100  is in motion as the movement of the user occupying the terminal  100 , the terminal  100  acquires the acceleration information. The terminal  100  acquires the atmospheric pressure information by measuring atmospheric pressure of the surroundings that changes with the movement of the terminal  100 . The terminal  100  acquires the sound information by detecting sound of the surroundings that change with the movement of the terminal  100 . 
     According to another embodiment, the context information includes history information related to connections of the terminal  100  with another terminal present at a particular location. For example, the connection history information includes history information indicating that the terminal  100  has received power from a wireless charging device present at the particular location and history information indicating that the terminal  100  has received signals from a sensor device present at the particular location. 
     The examples of the context information are provided to explain the present disclosure, and the context information of the present disclosure is not limited thereto. 
     In step S 220 , the terminal  100  determines the location of the terminal  100  by comparing the acquired context information with patterns information representing the target location set previously. The patterns information may be generated based on the acceleration information, the atmospheric pressure information, the sound information, and the connection history information that may be acquired when the terminal is present at the target location. 
     For example, since the atmospheric pressure in the vehicle  5  may be different from the pressure outside the vehicle  5 , the terminal  100  includes the atmospheric pressure in the vehicle  5  in the patterns information representing the inside of the vehicle  5 . When the user  10  is riding in the vehicle  5 , the terminal  100  determines the acceleration information of the terminal  100  as one of the patterns information representing the inside of the vehicle  5 . 
     The terminal  100  determines sound information that is detected when the user  10  is riding in the vehicle  5  as one of the patterns information representing the inside of the vehicle  5 . For example, the terminal  100  determines information of sounds that are generated when the user  10  opens and closes a door of the vehicle  5  as the patterns information representing the inside of the vehicle  5 . 
     According to another example, the terminal  100  determines the history information indicating that the terminal  100  has been charged from a wireless charging device present at the vehicle  5  as the patterns information. The terminal  100  determines the history information indicating that the terminal  100  has transmitted or received control signals to or from an on-board diagnostics (OBD) device present at the vehicle  5  as the patterns information. 
     In step S 230 , the terminal  100  determines at least one of the transmission power and the scan period, for communications with another terminal, according to the characteristics of determined location. 
     The terminal  100  stores characteristics information for each target location. The characteristics information includes information related to size of the target location and information related to mobility of the terminal. For example, when the location of the terminal  100  is determined to be the inside of the vehicle  5 , the terminal  100  detects information regarding maximum distance in the vehicle  5  from its memory. 
     The terminal  100  may be offered for the tethering for another terminal. The terminal  100  transmits the beacon frame for searching the other terminal to be tethered. The terminal  100  determines, according to the determined characteristics of the determined location, at least one of the transmission power and the scan period for transmitting the beacon frame. 
     For example, when the terminal  100  is located in the vehicle  5 , the terminal  100  increases the scan period or stops the scanning operation. When the terminal  100  is located in the vehicle  5 , the terminal  100  decreases the transmission power. The terminal  100  may also change the transmission power depending on type of the vehicle  5 , which is described in detail below with reference to  FIGS. 6A and 6B . 
       FIG. 3  is a flowchart explaining a method that the terminal  100  determines at least one of the transmission power and the scan period according to characteristics of the terminal location that is determined based on information detected from the surroundings in accordance with an embodiment of the present disclosure. 
     In step  310 , the terminal  100  acquires the context information including at least one of the acceleration information, the atmospheric pressure information, and the sound information that may represent the location of the terminal  100 . 
     The terminal  100  acquires the context information according to a predetermined period. For example, the terminal  100  acquires the acceleration information that represents the motion of the terminal  100  in a predetermined period. Alternatively, the terminal  100  acquires the atmospheric pressure information that represents the atmospheric pressure of the surrounding environment of the terminal  100  in a predetermined period, or acquires the sound information by detecting the sound of the surroundings of the terminal  100  in a predetermined period. 
     In step S 320 , the terminal  100  determines whether at least one of the acquired information, such as the acceleration information, the atmospheric pressure information, and the sound information corresponds to the patterns information representing the target location. 
     The terminal  100  stores the patterns information regarding at least one target location in advance. For example, the terminal  100  stores, in advance, the patterns information representing that the terminal  100  is located inside the vehicle  5 . 
     According to an embodiment, the terminal  100  generates the patterns information based on the context information that the terminal  100  acquired in the target location previously. For example, when the user occupying the terminal  100  is riding in the vehicle  5 , the terminal  100  generates the patterns information for the vehicle  5  by using the acceleration information that is determined by changes of velocity of the terminal  100  according to the following Equation (1): 
     
       
         
           
             
               
                 
                   
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     In the above equation, Pacc denotes the patterns information determined based on the acceleration information, and accXi, accYi, and accZi denote accelerations in the x-axis, y-axis, and z-axis directions, respectively. Also, n denotes the number of acquisitions of the acceleration information. 
     According to another embodiment, the terminal  100  generates the patterns information for the vehicle  5  by using the atmospheric pressure information that is changing as the door of the vehicle  5  is closed after the user enters the vehicle  5 . 
     According to yet another embodiment, the terminal  100  measures sound being generated when the door of the vehicle  5  is closed after the user enters the vehicle  5  for example, and generates the patterns information based on measured sound. 
     According to an embodiment, the terminal  100  determines whether a difference between the patterns information of the target location previously set and at least one of the acquired information, such as the acceleration information, the atmospheric pressure information, and the sound information, is equal to or less than a predetermined threshold. For example, the terminal  100  calculates a context value based on at least one of the acquired information, such as the acceleration information, the atmospheric pressure information, and the sound information, by using an algorithm or rule that is the same as that used in generating the patterns information, and compares the calculated context value with the patterns information to determine whether a difference between the calculated context value and the patterns information is less than or equal to the threshold. 
     If the difference between the calculated context value and the patterns information is greater than the threshold, the terminal  100  determines that the location of the terminal  100  does not correspond to the target location. If the location of the terminal  100  does not correspond to the target location, the terminal  100  returns to step S 310  of acquiring the context information. 
     If the context information corresponds to the patterns information of the target location, the terminal  100  determines the target location as the location of the terminal  100  in step S 330 . For example, the terminal  100  determines that the terminal  100  is located in the vehicle  5  as the context information corresponds to the patterns information of the target location. 
     In step S 340 , the terminal  100  determines at least one of the transmission power and the scan period, for communications with another terminal, according to the characteristics of determined location. 
     The terminal  100  may be offered for the tethering for another terminal. The terminal  100  transmits the beacon frame for searching the other terminal to be tethered. The terminal  100  determines, according to the determined characteristics of the determined location, at least one of the transmission power and the scan period for transmitting the beacon frame. For example, the terminal  100  determines the magnitude of the transmission power based on a maximum distance between the terminal  100  and the other terminal. The terminal  100  increases the scan period when the distance between the terminal  100  and the other terminal at the determined location is unlikely to change beyond a predetermined range. 
     When the terminal  100  is provided with the tethering service by another terminal, the terminal  100  controls the transmission power for transmitting frames to the other terminal depending on the characteristics of the location of the terminal  100 . 
       FIG. 4  is a flowchart explaining a method that the terminal  100  determines at least one of the transmission power and the scan period according to characteristics of the terminal location that is determined based on history information of connections between the terminal  100  and another device present at the target location in accordance with an embodiment of the present disclosure. 
     In step S 410 , the terminal  100  monitors the connection of the terminal  100  to another device that is present at a target location set previously. For example, the terminal  100  stores in advance, with respect to the vehicle  5 , types of information transmitted to or received to and from the wireless charging device or the OBD device when the terminal  100  is connected to the wireless charging device or the OBD device located in the vehicle  5 . 
     The terminal  100  monitors whether the terminal  100  receives power from the wireless charging device located in the vehicle  5 . The terminal  100  monitors whether the terminal  100  transmits or receives control signals to or from the OBD device in the vehicle  5  according to a predetermined period. 
     In step S 420 , the terminal  100  determines whether another device present at a target location previously set is connected to the terminal  100 . 
     The terminal  100  determines that the other device is connected to the terminal  100  when the other device continuously transmits or receives information to and from the terminal  100 . For example, the terminal  100  determines that the terminal  100  is connected to the wireless charging device if thirty (30) seconds has not elapsed since the most recent time of receiving the power from the wireless charging device. The terminal  100  determines that the terminal  100  is not connected to the wireless charging device if more than thirty seconds has elapsed since the most recent time of receiving the power from the wireless charging device. 
     If it is determined that terminal  100  is not connected to the other device present at the target location, the terminal  100  returns to step S 410  for monitoring another device. 
     If it is determined that the terminal  100  is connected to the other device present at the target location, the terminal  100  determines the target location as the location of the terminal  100  in step S 430 . For example, if the terminal  100  is determined to be connected to the wireless charging device or the OBD device located in the vehicle  5 , the terminal  100  may be determined as being inside the vehicle  5 . 
     In step S 440 , the terminal  100  determines at least one of the transmission power and the scan period, for communications with another terminal, according to the characteristics of determined location. 
     The terminal  100  may be offered for the tethering for another terminal. The terminal  100  transmits the beacon frame for searching the other terminal to be tethered. The terminal  100  determines, according to the determined characteristics of the determined location, at least one of the transmission power and the scan period for transmitting the beacon frame. For example, the terminal  100  determines the magnitude of the transmission power based on a maximum distance between the terminal  100  and the other terminal. The terminal  100  increases the scan period when the distance between the terminal  100  and the other terminal at the determined location is unlikely to change beyond a predetermined range. 
     When the terminal  100  is provided with the tethering service by another terminal, the terminal  100  controls the transmission power for transmitting frames to the other terminal depending on the characteristics of the location of the terminal  100 . 
       FIG. 5  illustrates a method for determining at least one of the transmission power and the scan period according to characteristics of the terminal location that is determined based on the connection of the terminal  100  and another device  510  present at a target location  505  in accordance with an embodiment of the present disclosure. 
     Referring to  FIG. 5 , the terminal  100  is located in the vehicle  505 . 
     The terminal  100  receives power from a wireless charging device  510  along with a frame representing information of the wireless charging device  510 . The terminal  100  identifies the wireless charging device  510  by use of an identification value or a manufacturer code of the wireless charging device  510  contained in the frame received from the wireless charging device  510 . 
     The terminal  100  determines that the terminal  100  is located inside the vehicle  505  when the terminal  100  receives power from the wireless charging device  510 . For example, the terminal  100  compares an acquired identification value of the wireless charging device  510  with an identification value stored previously for the wireless charging device  510  that is one of devices located inside the vehicle  505 . 
     The terminal  100  determines the magnitude of the transmission power used for the tethering in consideration of a size of the vehicle  505 . For example, the terminal  100  determines the magnitude of the transmission power for transmitting a management frame such as a beacon frame used for searching other terminals and the transmission power for broadcasting or unicasting data frames. When the terminal  100  is located in the vehicle  5 , the tethering is accomplished in a limited space. In this case, the terminal  100  decreases the magnitude of the transmission power used for transmitting the frames in consideration of the size of the vehicle  505 . 
     When the terminal  100  in the vehicle  505  is provided with the tethering service by another terminal in the vehicle  505 , the terminal  100  controls the transmission power for transmitting frames to the other terminal in consideration of the size of the vehicle  505 . For example, the terminal  100  controls the transmission power for transmitting the beacon frame and data frames to the other terminal. 
     Also, when the terminal  100  is located in the vehicle  505 , the movable range of the other terminal which uses the tethering service from the terminal  100  may be limited. Thus, the terminal decreases the period for scanning other terminals in the vehicle  505  that may be tethered by the terminal  100 . 
       FIGS. 6A and 6B  illustrate a method for determining the transmission power based on types of vehicles  610  and  620  in accordance with an embodiment of the present disclosure. 
     When the terminal  100  is located in the vehicle  610  or  620 , the terminal  100  may be connected to the OBD device installed in the vehicle  610  or  620 . As the user occupying the terminal  100  rides in the vehicle  610  or  620 , the terminal  100  receives identification information of the vehicle  610  or  620  from the OBD device. 
     For example, the terminal  100  receives a vehicle identification number (VIN) of the vehicle  610  or  620  from the OBD device. The terminal  100  acquires information indicating that the terminal  100  is located inside of the vehicle  610  or  620  and the information related to the type of the vehicle  610  or  620  by use of the VIN information. 
     The terminal  100  determines the transmission power required for the terminal  100  to provide the tethering to other terminals in the vehicle  610  or  620  based on size information of the vehicle  610  or  620  that corresponds to the type of the vehicle  610  or  620 . 
     For example, the terminal  100  determines the magnitude of the transmission power based on information indicating that a maximum distance between two points inside the vehicle  610  or  620  is ‘X’. When the transmission power is set to ‘5A’ for tethering devices spaced apart by a distance of ‘5X’ outside the vehicle  610  or  620 , the terminal  100  changes the transmission power into a value less than ‘A’ inside the vehicle  610  or  620  in which the maximum distance is ‘X’. 
     According to another embodiment, when the terminal  100  in the vehicle  610  or  620  is provided with the tethering service by another terminal in the vehicle  610  or  620 , the terminal  100  controls the transmission power for transmitting frames to the other terminal in consideration of the size of the vehicle  610  or  620 . For example, the terminal  100  controls the transmission power for transmitting the beacon frame and data frames to the other terminal. 
     Meanwhile, the terminal  100  changes the transmission power according to the type of the vehicle  610  or  620 . 
     Referring to  FIG. 6A , when the user occupying the terminal  100  rides in a first vehicle  610 , the terminal  100  receives the VIN information of the first vehicle  610  from a first OBD device. The terminal  100  compares received VIN information with VIN information of a plurality of vehicles stored previously in the terminal  100  to determine that the terminal  100  is located inside the first vehicle  610 . 
     The terminal  100  determines the transmission power for providing the tethering service inside the first vehicle  610  by use of the information related to the maximum distance between two points inside the first vehicle  610  stored previously in the terminal  100 . It is assumed that the maximum distance inside the first vehicle  610  is ‘2X’. When the transmission power is set to ‘5A’ for tethering devices spaced apart by a distance of ‘5X’ outside the first vehicle  610 , the terminal  100  changes the transmission power into a value less than ‘2A’ inside the first vehicle  610  where the maximum distance is ‘2X’. 
     Referring to  FIG. 6B , when the user occupying the terminal  100  rides in a second vehicle  620 , the terminal  100  receives the VIN information of the second vehicle  620  from a second OBD device. The terminal  100  compares received VIN information with VIN information of a plurality of vehicles stored previously in the terminal  100  to determine that the terminal  100  is located inside the second vehicle  620 . 
     The terminal  100  determines the transmission power for providing the tethering service inside the second vehicle  620  by use of the information related to the maximum distance between two points inside the second vehicle  620  stored previously in the terminal  100 . It is assumed that the maximum distance inside the second vehicle  620  is ‘X’. When the transmission power is set to ‘5A’ for tethering devices spaced apart by a distance of ‘5X’ outside the second vehicle  620 , the terminal  100  changes the transmission power into a value less than ‘A’ inside the first vehicle  610  where the maximum distance is ‘X’. 
       FIGS. 7A and 7B  illustrate a method for determining scan periods for other terminals according to characteristics of the location of the terminal  100  in accordance with an embodiment of the present disclosure. 
     Referring to  FIG. 7A , when the terminal  100  is located in open space, the terminal  100  searches other terminals or access points (APs)  710  and  720  based on a predetermined scan period as the user is in motion. 
     For example, the terminal  100  may be connected to a first access point  710  at a first location but to a second access point  720 , at a second location, that is closer than the first access point  710  after the terminal  100  moves to the second location. 
     If the terminal  100  provides the tethering to other terminals, the terminal  100  may also search other terminals according to a predetermined scan period to update information related to nearby devices as the terminal  100  is in motion. 
     Referring to  FIG. 7B , the terminal  100  may be located inside a vehicle  705 . The terminal  100  determines that the terminal  100  is located inside the vehicle  705  by using the acquired context information. The method that the terminal  100  uses to determine whether the terminal  100  is located inside the vehicle  705  by using the acquired context information is the same as the previously-described method. 
     When the terminal  100  is located in limited space such as inside of the vehicle  705 , the terminal  100  decreases the scan period since the other devices located in the neighborhood of the terminal  100  are unlikely to change compared with the case of  FIG. 7A . 
     For example, if the terminal  100  in  FIG. 7B  provides the tethering to other terminals inside the vehicle  705 , the terminal  100  and another terminal  730  are located inside the vehicle  730  while maintaining their distance even when the vehicle  705  is in motion and thus the terminal decreases the scan period. 
       FIG. 8  is a flowchart explaining a method that the terminal  100  acquires the context information in a predetermined interval and updates the information related to the location of the terminal  100  in accordance with an embodiment of the present disclosure. 
     In step S 810 , the terminal  100  acquires the context information that represents the location of the terminal  100 . 
     The context information includes the acceleration information of the terminal  100 , the atmospheric pressure and sound information of the surroundings. According to another embodiment, the context information includes history information of the connections between the terminal  100  and other terminals in particular location. 
     In step S 820 , the terminal  100  compares the acquired context information with patterns information representing the target location set previously. The patterns information may be generated based on the acceleration information, the atmospheric pressure information, the sound information, and the connection history information that may be acquired when the terminal is present at the target location. 
     If the acquired context information does not correspond to the patterns information of the target location, the terminal returns to step S 810  of acquiring the context information. 
     In step S 830 , the terminal  100  determines at least one of the transmission power and the scan period, for communications with another terminal, according to the characteristics of determined location. 
     The terminal  100  stores characteristics information for each target location. The characteristics information includes information related to size of the target location and mobility of the terminal. 
     The terminal  100  may be offered for the tethering for another terminal. The terminal  100  transmits the beacon frame for searching the other terminal to be tethered. The terminal  100  determines, according to the determined characteristics of the determined location, at least one of the transmission power and the scan period for transmitting the beacon frame. 
     According to another embodiment, when the terminal  100  in the vehicle  5  is provided with the tethering service by another terminal in the vehicle  5 , the terminal  100  controls the transmission power for transmitting frames to the other terminal in consideration of the size of the vehicle  5 . 
     In step S 840 , the terminal  100  acquires the context information representing the location of the terminal  100 . In step S 850 , the terminal  100  compares newly acquired context information with patterns information representing target location determined previously. According to an embodiment, the terminal  100  compares the context information updated in step S 840  with patterns information representing target location determined based on the context information acquired previously. 
     In step S 860 , if the updated context information corresponds to the patterns information representing the target location determined based on the context information acquired previously, the terminal  100  maintains the transmission power and the scan period. 
     In step S 870 , if the updated context information does not correspond to the patterns information representing the target location determined based on the context information acquired previously, the terminal  100  changes the transmission power and the scan period according to characteristics of a location newly determined based on the updated context information. 
       FIG. 9  is a flowchart explaining a method that the terminal  100  transmits information of at least one of the transmission power and the scan period to another terminal present at a target location when the terminal  100  is located at the target location, according to an embodiment of the present disclosure. 
     In step S 910 , the terminal  100  acquires the context information that represents the location of the terminal  100 . 
     The context information includes the acceleration information of the terminal  100 , the atmospheric pressure and sound information of the surroundings. According to another embodiment, the context information includes history information of the connections between the terminal  100  and other terminals in particular location. In step S 920 , the terminal  100  determines the location of the terminal  100  by comparing the acquired context information with patterns information representing the target location set previously. The patterns information may be generated based on the acceleration information, the atmospheric pressure information, the sound information, and the connection history information that may be acquired when the terminal is present at the target location. 
     In step S 930 , the terminal  100  determines at least one of the transmission power and the scan period, for communications with another terminal, according to the characteristics of determined location. In step S 940 , the terminal  100  transmits information related to at least one of the transmission power and the scan period determined in step S 930  to the other terminal to which a communications channel is being established. 
     The terminal  100  establishes a communications channel to the other terminal present at the target location, such as by broadcasting or unicasting the beacon frame according to the transmission power and the scan period determined as in step S 930 . 
     The other terminal for which the communications channel is established to the terminal  100  receives the information related to at least one of the transmission power and the scan period from the terminal  100 , and changes the transmission power or the scan period corresponding to the target location without any need for separately acquiring the context information and determining its location. 
       FIG. 10  illustrates a method that a terminal  1010  transmits information of at least one of the transmission power and the scan period to another terminal  1020  present at a target location when the terminal  1010  is located at the target location, according to an embodiment of the present disclosure. 
     The terminal  1010  acquires context information representing the location of the terminal  1010 . For example, the terminal  1010  acquires at least one of: atmospheric pressure and the sound information of the surroundings. According to another embodiment, the terminal  1010  acquires history information of the terminal  100  about connections with other terminals present at a particular location. 
     The terminal  1010  determines the location of the terminal  1010  by comparing acquired context information with patterns information representing a vehicle  1005 . For example, the terminal  1010  acquires information related to the maximum distance inside the vehicle  1050  or mobility of the terminal by comparing the acquired context information with the patterns information. 
     The terminal  1010  increases the scan period when the terminal  1010  is located in limited space of the vehicle  1005 . The terminal  1010  determines the magnitude of the transmission power used for the tethering in consideration of the maximum distance inside the vehicle  1005 . 
     The terminal  1010  establishes a communications channel with another terminal  1020  present inside the vehicle  1005  according to the transmission power and the scan period determined as previously described. When the communications channel is established between the terminal  1010  and the other terminal  1020 , the terminal  1010  transmits the information related to the transmission power and the scan period to the other terminal  1020 . 
     The other terminal  1020  for which the communications channel is established to the terminal  1010  receives the information related to the transmission power and the scan period from the terminal  1010 , and changes the transmission power or the scan period corresponding to the target location without any need for separately acquiring the context information and determining its location. 
       FIGS. 11 and 12  are block diagrams of the terminal  100  according to an embodiment of the present disclosure. 
     As shown in  FIG. 11 , the terminal  100  includes a context information acquirer  110 , a position determiner  120 , and a controller  130 . However, it should be noted that not all the elements shown in the drawings are essential, and the terminal  100  may be implemented to include additional or fewer elements than those illustrated. 
     For example, as shown in  FIG. 11 , the terminal  100  includes an audio/video (AN) input unit  140 , an output unit  150 , a communicator  160 , and a memory  170  in addition to the context information acquirer  110 , the position determiner  120 , and the controller  130 . 
     The configuration of the terminal  100  will now be described in detail. 
     The context information acquirer  110  acquires the context information representing the location of the terminal  100 . The context information includes the acceleration information of the terminal  100 , the atmospheric pressure and sound information of the surroundings. According to another embodiment, the context information includes history information of the connections between the terminal  100  and other terminals present at particular locations. The context information acquirer  110  acquires the connection history information by monitoring connections of the terminal  100  with the other terminals present at the particular locations. 
     The context information acquirer  110  may be a sensing unit which includes at least one of: a geomagnetic sensor  111 , an accelerometer  112 , a temperature and humidity sensor  113 , an infrared sensor  114 , a gyroscopic sensor  115 , a position sensor  116  such as a GPS signal receiver, a barometer  117 , a proximity sensor  118 , an illuminance sensor  119 . 
     The context information acquirer  110  receives, from an A/V input unit  140  described below, the sound information representing sound being generated in the surroundings of the terminal  100  and acquired by the A/V input unit  140 . 
     The position determiner  120  determines the location of the terminal  100  by comparing the acquired context information with patterns information representing the target location previously set. The patterns information may be generated based on the acceleration information, the atmospheric pressure information, the sound information, and the connection history information that may be acquired when the terminal is present at the target location. 
     The position determiner  120  determines whether at least one of the acquired information, such as the acceleration information, the atmospheric pressure information, and the sound information corresponds to the patterns information representing the target location. If the acquired information corresponds to the patterns information of the target location, the position determiner  120  determines the target location as the location of the terminal  100 . For example, the position determiner  120  determines whether a difference between the patterns information of the target location previously set and at least one of the acquired information, such as the acceleration information, the atmospheric pressure information, and the sound information, is equal to or less than the predetermined threshold. The position determiner  120  calculates a context value based on at least one of the acquired information, such as the acceleration information, the atmospheric pressure information, and the sound information, by using an algorithm or rule that is the same as that used in generating the patterns information, and compares the calculated context value with the patterns information to determine whether a difference between the calculated context value and the patterns information is equal to or less than the threshold. 
     The position determiner  120  determines whether another device present at a target location previously set is connected to the terminal  100 . According to an embodiment, the position determiner  120  determines that the other device is connected to the terminal  100  when the other device continuously transmits or receives information to and from the communicator  160  of the terminal  100 . 
     The position determiner  120  determines the type of the vehicle  5  also by use of the context information when the location of the terminal  100  is inside the vehicle  5 . 
     The controller  130  generally controls overall operation of the terminal  100 , such as the sensing unit  110 , the AN input unit  140 , the output unit  150 , the communicator  160 , the memory  170 , and the user input unit  180  by executing programs stored in the memory  170 . 
     The controller  130  generates the patterns information based on the context information indicating that the terminal  100  acquired in the target location. For example, when the user occupying the terminal  100  is riding in the vehicle  5 , the controller  130  generates the patterns information representing the vehicle  5  based on the acceleration information indicating that is determined by changes of velocity of the terminal  100   
     According to another embodiment, the controller  130  generates the patterns information for the vehicle  5  by using the atmospheric pressure information that is changing as the door of the vehicle  5  is closed after the user enters the vehicle  5 . 
     According to another embodiment, the controller  130  measures sound being generated when the door of the vehicle  5  is closed after the user enters the vehicle  5  for example, and generates the patterns information based on measured sound. The controller  130  generates the patterns information of the vehicle  5  using the connection history information that represents exchange of information between the terminal  100  and the other device present inside the vehicle  5 . 
     The controller  130  determines at least one of the transmission power and the scan period, for communications of the terminal  100  with another terminal, according to the characteristics of the location of the terminal  100  determined by the position determiner  120 . 
     For example, the controller  130  determines the magnitude of the transmission power based on a maximum distance between the terminal  100  and the other terminal. The controller  130  increases the scan period when the distance between the terminal  100  and the other terminal at the determined location is unlikely to change beyond a predetermined range. 
     That is, when the terminal  100  is located inside the vehicle  5 , the controller  130  decreases the transmission power compared with a situation when the terminal  100  is located outside the vehicle  5 . When the terminal  100  is located inside the vehicle  5 , the controller  130  increases the scan period compared with a situation when the terminal  100  is located outside the vehicle  5 . The controller  130  may stop searching additional terminals when a communications channel is established between the terminal  100  and the other terminal in the vehicle  5 . 
     When the type of the vehicle  5  in which the terminal  100  is located was determined based on the context information, the controller  130  changes the transmission power based on an internal distance of the vehicle  5  which is identifiable from the type of the vehicle  5 . 
     According to another embodiment, when the terminal  100  is provided with the tethering service by another terminal, the controller  130  controls the transmission power for transmitting frames to the other terminal depending on the characteristics of the location of the terminal  100 . 
     The A/V input unit  140  receives audio signals or video signals and includes a camera  141  and a microphone  142 . The camera  141  acquires still images or video frames of a moving picture through an image sensor in a video call mode or a photograph mode. The images captured through the image sensor may be processed by the controller  130  or a separate image processor. 
     The video frames processed by the camera  141  are stored in the memory  170  or transmitted externally through the communicator  160 . The camera  141  may be provided in plural form depending on the implementation. 
     The microphone  142  receives external sounds and transforms the sound into electric sound signals. For example, the microphone  142  receives the sound from an external device or a caller. 
     For instance, the microphone  142  receives various sounds such as the sound of opening or slamming a door when the user occupying the terminal  100  rides in the vehicle  5  and the sound of sitting on a seat of the vehicle  5 . 
     The microphone  142  utilizes various noise reduction algorithms to reduce noises introduced during the input of the external sounds. 
     The output unit  150  includes a display  151 , an acoustic output unit  152 , and a vibration motor  153 . 
     The display  151 . outputs information processed by the terminal  100 . When the display  151  is implemented as a touch screen where a display panel and a touch pad compose a layer structure, the display  151  may be used as an output device as well as an input device. The display  151  includes at least one of: a liquid crystal display (LCD), a thin film transistor-liquid crystal display (TFT-LCD), an organic light-emitting diode (OLED) display, a flexible display, a three dimensional (3D) display, and an electrophoretic display. The terminal  100  includes two or more displays  151  depending on the implementation. The displays  151  may be disposed to face each other by use of a hinge. 
     The acoustic output unit  152  outputs audio data received from the communicator  160  or stored in a memory  170 , and outputs acoustic sounds related with operations performed by the terminal  100  such as ringtones, message ringtones, and notification sounds. The acoustic output unit  152  includes a speaker and a buzzer. 
     The vibration motor  153  generates vibrations. For example, the vibration motor  153  outputs vibrations corresponding to video outputs or audio outputs such as the ringtone and the message ringtone, and outputs vibrations when a touch input is applied to a touch screen. 
     The communicator  160  transmits information related to at least one of the transmission power and the scan period determined by the controller  130  to the other terminal. The communicator  160  facilitates communications between the terminal  100  and the other device present at the target location. 
     The communicator  160  includes at least one element for enabling communications between the terminal  100  and at least one other device or between the terminal  100  and another terminal. For example, the communicator  160  includes a short-range wireless communicator  161 , a mobile communicator  162 , and a broadcast receiver  163 . 
     The short-range wireless communicator  161  includes, but is not limited to, a Bluetooth™ communicator, a Bluetooth low energy (BLE) communicator, a wireless LAN communicator, a near field communication (NFC) unit, an Ant+ communicator, a ZigBee communicator, an infrared data association (IrDA) communicator, a WiFi communicator, WiFi-direct (WFD) communicator, and an ultra-wideband (UWB) communicator. 
     The mobile communicator  162  transmits and receives wireless signals to and from at least one of a base station of a mobile communications network, an external terminal, and a server. The wireless signals include various kinds of data related with transmission and receipt of voice call signals, video call signals, text messages, or multimedia messages. 
     The broadcast receiver  163  receives broadcast signals and/or broadcast related information through broadcast channels. The broadcast channels include satellite broadcast channels and terrestrial broadcast channels. The broadcast receiver  163  may not be included in the terminal  100  depending on the implementation of the terminal  100 . 
     The memory  170  stores programs for processing and control operations of the controller  130  and data input to the terminal  100  or output from the terminal  100 , such as a plurality of menus, a first hierarchical sub-menu corresponding to respective one of the plurality of menu, and a second hierarchical sub-menu corresponding to respective one of the first hierarchical sub-menus. 
     The memory  170  stores patterns information that represents target locations generated by the controller  130 . For example, the memory  170  stores patterns information that represents the vehicle  5 , and stores patterns information for each type of the vehicle  5  and characteristics information for each type of the vehicle  5 . The characteristics information includes information of the maximum distance in the vehicle  5 . 
     The memory  170  includes at least one of a flash memory, a hard disk, a multimedia card micro, a card-type memory such as a SD or XD memory, a random access memory (RAM), a read-only memory (ROM), an electrically erasable and programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disc, and an optical disk. The terminal  100  may operate a web storage or a cloud server that performs storing function of the memory  170  on the Internet. 
     The programs stored in the memory  170  may be categorized into a plurality of modules, according to their functions, such as a user interface (UI) module  171 , a touch screen module  172 , and a notification module  173 . 
     The UI module  171  provides a user interface or graphic user interface that is specialized for each application and interacts with the terminal  100 . The touch screen module  172  senses touch gestures on a touch screen of the user, and may transfer the touch gesture information to the controller  130 . The touch screen module  172  according to some embodiments may recognize and analyze touch codes. The touch screen module  172  may be configured as a separate hardware including the controller. 
     Various sensors may be provided in or near the touch screen to sense a touch or a hovering of the touch screen. One example of the sensor for sensing the touch of the touch screen is a tactile sensor. The tactile sensor detects the stimulus of a contact on a specific object in a human sensitivity or a higher sensitivity, and detects various information such as the roughness of a touched surface, the hardness of a touching body, and the temperature of a touched position. 
     Another example of the sensor for sensing the touch of the touch screen is a proximity sensor, which detects the presence of an object approaching a predetermined detection surface or a nearby object by use of electromagnetic field intensity or infrared ray without any physical contact. Examples of the proximity sensor include a through-beam photoelectric sensor, a diffuse-reflective photoelectric sensor, a retro-reflective photoelectric sensor, a high frequency oscillation proximity sensor, a capacitance proximity sensor, a magnetic proximity sensor, and an infrared proximity sensor. The touch gestures of the user may include ‘tap’, ‘double tap’, ‘to touch and hold’, ‘to drag item’, ‘to slide finger’, ‘to flick finger’, ‘to drag and drop item’, and ‘to swipe’. 
     The notification module  173  generates a signal for notifying an event occurred in the terminal  100 , such as receiving a call, receiving a message, a key input entry, and a schedule notification. The notification module  173  outputs notifications in a video form through the display  151 , in an audio form through the acoustic output unit  152 , or in vibrations through the vibration motor  153 . 
     The user input unit  180  may be used to receive user input for controlling the terminal  100 . Examples of the user input unit  180  include, but are not limited to, a keypad, a dome switch, a touchpad, a jog wheel, and a jog switch. In particular, the touchpad may be one of various types including capacitive overlay, resistive overlay, infrared beam, surface acoustic wave, integral strain gauge, and piezoelectric types. 
     The methods according to embodiments of the present disclosure may be implemented as computer instructions which can be executed by various computer means, and recorded on a non-transitory computer-readable medium. The computer-readable medium may include program commands, data files, data structures or a combination thereof. Program instructions recorded on the medium may be particularly designed and structured for the inventive concept or available to those skilled in computer software. 
     Examples of a non-transitory computer-readable recording medium include magnetic media such as a hard disk, a floppy disk, and a magnetic tape, optical media such as compact disk-read only memory (CD-ROM) and a digital versatile disc (DVD), magneto-optical media such as a floptical disk, a read-only memory (ROM), random access memory (RAM), and flash memory. The medium may be a transmission medium, such as an optical or metal line, a waveguide, or carrier waves transferring program commands, data structures, and the like. 
     Program commands may include, for example, a high-level language code that can be executed by a computer using a compiler or an interpreter, as well as a machine language code generated by a compiler. 
     It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. 
     While one or more 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.