Abstract:
A system and method for setting an ad-hoc network in a terminal are provided. The system includes a storage unit for storing a critical value of acceleration of the terminal, an acceleration sensor for measuring the acceleration of the terminal to provide a value of the measured acceleration, and a transmission frame processor for controlling transmission of a Media Access Control (MAC) frame for setting the network depending on whether the value of the acceleration measured by the acceleration sensor exceeds the critical value of acceleration pre-stored in the storage unit. The system performs Radio Frequency (RF) control on the terminals, each of which must operate as a host and a router in the ad-hoc network, using the acceleration sensor, thereby preventing use of unnecessary resources and reducing an amount of unnecessarily broadcast frames.

Description:
PRIORITY 
       [0001]    This application claims the benefit under 35 U.S.C. § 119(a) of a Korean patent application filed in the Korean Intellectual Property Office on Jan. 21, 2008 and assigned Serial No. 10-2008-0006321, the entire disclosure of which is hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an ad-hoc mode supported in a wireless network system. More particularly, the present invention relates to the enabling of a routing protocol to effectively operate in an ad-hoc mode. 
         [0004]    2. Description of the Related Art 
         [0005]    Among the wireless network systems, the Wireless Local Area Network (WLAN) of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard is generally designed to support two modes of operation. 
         [0006]    The first mode is an infrastructure mode in which terminals (e.g. stations, mobile nodes, etc.) can communicate with each other using an Access Point (AP). The other mode is an ad-hoc mode in which terminals can communicate with each other without an AP. 
         [0007]    In the infrastructure mode, the terminals operate as hosts and the AP operates as a router that uses the same protocol as Inter AP Protocol (IAPP) of the IEEE 802.11f standard. 
         [0008]    In contrast, in the ad-hoc mode, the terminals must directly communicate with each other because the AP is not used. 
         [0009]    More specifically, in the ad-hoc mode each terminal must operate as a host and a router. Due to mobility and limited power that are characteristic of the terminals, the terminals based on the ad-hoc mode are distinguished from those based on the infrastructure mode. 
         [0010]    In the ad-hoc mode, the mobility and limited power resources of any particular node (or terminal) make it difficult to communicate with the other terminals. 
         [0011]    Thus, a special routing protocol reflecting features of the ad-hoc mode is required. Recently, a study has been made of on-demand routing protocols such as an Ad-hoc On-demand Distance Vector (ADOV) routing protocol (IETF RFC 3561) and a Dynamic Source Routing (DSR) Protocol (IETF RFC 4728). However, there remains a need for a routing protocol that addresses the needs of an ad-hoc infrastructure. 
       SUMMARY OF THE INVENTION 
       [0012]    An aspect of the present invention is to address the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a system for setting an ad-hoc network for a terminal and a method of controlling the same, in which, among the variable factors of ad-hoc, information about movement of the terminal is measured to efficiently control an Radio Frequency (RF), thereby making it possible for a routing protocol to operate in a more stable and efficient manner. 
         [0013]    According to an aspect of the invention, a system for setting an ad-hoc network in a transmitting terminal is provided. The system includes a storage unit for storing a critical value of acceleration of the terminal, an acceleration sensor for measuring the acceleration of the terminal to provide a value of the measured acceleration, and a transmission frame processor for controlling transmission of a Media Access Control (MAC) frame for setting the network depending on whether the value of the acceleration measured by the acceleration sensor exceeds the critical value of acceleration pre-stored in the storage unit. 
         [0014]    In an exemplary embodiment of the present invention, the transmission frame processor may not transmit the MAC frame if the value of the acceleration measured by the acceleration sensor exceeds the critical value of acceleration pre-stored in the storage unit, and add the value of the measured acceleration to an acceleration information field of the MAC frame and broadcast the MAC frame to surrounding receiving terminals thereof if the value of the measured acceleration does not exceed the critical value of acceleration pre-stored in the storage unit. 
         [0015]    In another exemplary embodiment of the present invention, the transmission frame processor may use one of an automatic mode for processing the frame in a MAC layer and a manual mode for processing the frame in a routing protocol layer. 
         [0016]    According to another aspect of the invention, a system for setting an ad-hoc network in a receiving terminal is provided. The system includes a storage unit for storing a critical value of acceleration of the terminal, an acceleration field searcher for searching an acceleration information field of a Media Access Control (MAC) frame received from any transmitting terminal and for determining a value of the acceleration information field of the MAC frame of the transmitting terminal, an acceleration comparator for comparing the value of the acceleration information field searched by the acceleration field searcher with the critical value of acceleration pre-stored in the storage unit, and a reception frame processor for discarding the received MAC frame if the value of the acceleration information field of the MAC frame is greater than the critical value of acceleration pre-stored in the storage unit. 
         [0017]    In an exemplary embodiment of the present invention, the reception frame processor may use one of an automatic mode for processing the frame in a MAC layer and a manual mode for processing the frame in a routing protocol layer. 
         [0018]    According to yet another aspect of the invention, a method of controlling a system for setting an ad-hoc network in a transmitting terminal is provided. The method includes measuring, by an acceleration sensor, acceleration of a transmitting terminal to provide a value of the measured acceleration, determining whether the value of the acceleration measured by the acceleration sensor exceeds a critical value of acceleration pre-stored in a storage unit and controlling transmission of a Media Access Control (MAC) frame for setting the network if the value of the measured acceleration exceeds the critical value of acceleration pre-stored in the storage unit. 
         [0019]    In an exemplary embodiment of the present invention, the method may further include adding the value of the measured acceleration to an acceleration information field of the MAC frame and broadcasting the MAC frame to surrounding terminals if the value of the measured acceleration does not exceed the critical value of acceleration pre-stored in the storage unit. 
         [0020]    In another exemplary embodiment of the present invention, the controlling of the transmission of a MAC frame may be carried out using one of an automatic mode for processing the frame in a MAC layer and a manual mode for processing the frame in a routing protocol layer. 
         [0021]    According to still another aspect of the invention, a method of controlling a system for setting an ad-hoc network in a receiving terminal is provided. The method includes searching, by an acceleration field searcher, an acceleration information field of a Media Access Control (MAC) frame received from any transmitting terminal and checking a value of the acceleration information field of the MAC frame of the transmitting terminal, determining, by an acceleration comparator, whether the value of the acceleration information field searched by the acceleration field searcher is greater than a critical value of acceleration pre-stored in a storage unit, and discarding, by a reception frame processor, the received MAC frame if the value of the acceleration information field of the MAC frame is greater than the critical value of acceleration pre-stored in the storage unit. 
         [0022]    In an exemplary embodiment of the present invention, the discarding of the received MAC frame may be carried out using one of an automatic mode for processing the frame in a MAC layer and a manual mode for processing the frame in a routing protocol layer. 
         [0023]    As described above, according to exemplary embodiments of the present invention, the system for setting an ad-hoc network for a terminal and the method of controlling the same perform Radio Frequency (RF) control on the terminals, each of which must operate as a host and a router in the ad-hoc network, using the acceleration sensor, so that they can prevent use of unnecessary resources and reduce an amount of unnecessarily broadcast frames. 
         [0024]    Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The above and other aspects, features and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
           [0026]      FIG. 1  is a functional block diagram illustrating a configuration of a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention; 
           [0027]      FIG. 2A  illustrates a situation in which a transmitting terminal does not move around in a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention; 
           [0028]      FIG. 2B  illustrates a situation in which a transmitting terminal does move around in a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention; 
           [0029]      FIG. 3  illustrates a format of a MAC frame used in a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention; 
           [0030]      FIG. 4  is a flowchart illustrating a method of controlling a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention; 
           [0031]      FIG. 5  is a functional block diagram illustrating a configuration of a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention; and 
           [0032]      FIG. 6  is a flowchart illustrating a method of controlling a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention. 
       
    
    
       [0033]    Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features and structures. 
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0034]    The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiment of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness. 
         [0035]    The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
         [0036]    It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
         [0037]      FIG. 1  illustrates a configuration of a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention. In this exemplary embodiment, the system  100  for setting an ad-hoc network for a terminal includes a storage unit  110 , an acceleration sensor  120  and a transmission frame processor  130 . Also illustrated in  FIG. 1  is a plurality of surrounding receiving terminals  201 . For sake of convenience, only six surrounding receiving terminals are illustrated and each of the surrounding receiving terminals is labeled as a terminal  201 . However, this illustration is not to be considered limiting in that more or fewer terminals may surround the system  100  and the surrounding terminals need not be identical. 
         [0038]    The storage unit  110  may store a critical or threshold value of acceleration of a transmitting terminal associated with the system  100 . 
         [0039]    The acceleration sensor  120  measures the acceleration of the transmitting terminal  100 . That is, the acceleration sensor  120  determines an amount of movement of the transmitting terminal  100 , for example a displacement of the terminal over a given time. The acceleration sensor  120  provides a value of the measured acceleration to the transmission frame processor  130 . 
         [0040]    The transmission frame processor  130  controls transmission of a Media Access Control (MAC) frame for setting the network depending on whether the value of the acceleration measured by the acceleration sensor  120  exceeds the critical value of acceleration. In an exemplary implementation, the critical value of acceleration is pre-stored in the storage unit  110 . For example, the critical value of acceleration may be set by a terminal manufacturer. Alternatively, the critical value may be input by a user or may be received from a system administrator and may have different values depending on system parameters such as the number of surrounding terminals, channel conditions, conditions of the terminal and the like. 
         [0041]    If the value of the acceleration measured by the acceleration sensor  120  exceeds the critical value of acceleration, the transmission frame processor  130  does not transmit the MAC frame. Alternatively, if the value of the acceleration measured by the acceleration sensor  120  exceeds the critical value of acceleration, the transmission frame processor  130  does not add the value of the measured acceleration to the MAC frame and controls transmission of the MAC frame for setting a network. In contrast, if the value of the acceleration measured by the acceleration sensor  120  does not exceed the critical value of acceleration pre-stored in the storage  110 , the transmission frame processor  130  adds the value of the measured acceleration to an acceleration information field of the MAC frame, and then broadcasts the MAC frame to its surrounding receiving terminals  200  for setting an ad-hoc network. In an exemplary embodiment, the transmission frame processor  130  adds the actual value of movement or acceleration, as determined by the acceleration sensor, to the MAC frame. In another exemplary embodiment, the transmission frame processor  130  adds only an indication that the measured acceleration exceeds the critical value or not. In this case, the indication can be made using a single bit. 
         [0042]      FIG. 3  illustrates a format of a MAC frame used in a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention. 
         [0043]    Referring to  FIG. 3 , the MAC frame transmitted by the transmitting terminal  100  includes a frame control field (2 bytes), a duration ID field (2 bytes), an address1 field (6 bytes), an address2 field (6 bytes), an address3 field (6 bytes), a sequence control field (2 bytes), an address4 field (6 bytes), an acceleration information field (AV) field (2 bytes), a frame body field (0 to 2310 bytes), and a Frame Check Sequence (FCS) field (4 bytes). 
         [0044]    The transmission frame processor  130  may use one of an automatic mode for processing the frame in a MAC layer and a manual mode for processing the frame in a routing protocol layer. 
         [0045]      FIG. 2A  illustrates a situation in which a transmitting terminal does not move around in a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention and  FIG. 2B  illustrates a situation in which a transmitting terminal does move around in a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention. 
         [0046]    Referring to  FIGS. 2A and 2B , the acceleration sensor  120  measures acceleration of the transmitting terminal  100  and provides a value of the measured acceleration to the transmission frame processor  130 . In a situation in which the transmitting terminal  100  does not move around as illustrated in  FIG. 2A , the value of the measured acceleration is different from the value of measured acceleration in a situation in which the transmitting terminal  100  does move around as illustrated in  FIG. 2B . 
         [0047]    The transmission frame processor  130  determines whether the value measured by the acceleration sensor  120  exceeds a critical value of acceleration and thereby controls transmission of a MAC frame for setting the network. Again, the critical value of acceleration may be pre-stored in the storage unit  110 . 
         [0048]    As illustrated in  FIG. 2B , when the transmitting terminal  100  does move around to an extent that the value of the acceleration measured by the acceleration sensor  120  exceeds the critical value of acceleration, the transmission frame processor  130  does not transmit the MAC frame to its surrounding receiving terminals  201 . 
         [0049]    On the other hand, as illustrated in  FIG. 2A , if the transmitting terminal does not move around or if it only moves around an amount corresponding to a value less than the critical value, the value of the measured acceleration does not exceed the critical value of acceleration. In this case, as illustrated in  FIG. 3 , the transmission frame processor  130  adds the value of the measured acceleration to an AV field (acceleration information field) of the MAC frame and broadcasts the MAC frame to its surrounding receiving terminals  201 . 
         [0050]    Regarding the magnitude of acceleration, as illustrated in  FIG. 2B , although the transmitting terminal  100  does move around, the value of the measured acceleration may not exceed the critical value of acceleration. In this case, the transmission frame processor  130  adds the value of the measured acceleration to the AV field of the MAC frame and broadcasts the MAC frame to its surrounding receiving terminals  201 . 
         [0051]    The transmission frame processor  130  may use one of an automatic mode for processing the frame in a MAC layer and a manual mode for processing the frame in a routing protocol layer. 
         [0052]      FIG. 4  is a flowchart illustrating a method of controlling a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention. 
         [0053]    Referring to  FIG. 4 , the acceleration sensor  120  of a transmitting terminal  100  measures acceleration of the transmitting terminal  100  and provides a value of the measured acceleration to the transmission frame processor  130  in step S 1 . 
         [0054]    The transmitting terminal  100  determines whether the value of the acceleration measured by the acceleration sensor  120  exceeds the critical value of acceleration in step S 2 . 
         [0055]    As a result of the determination in step S 2 , if the value of the measured acceleration exceeds the critical value of acceleration (i.e. “Yes”), the transmitting terminal  100  controls transmission of the MAC frame for setting the network in step S 3 . That is, the transmitting terminal  100  transmits the MAC frame without adding the measured acceleration to the MAC frame. Alternatively, if the value of the measured acceleration exceeds the critical value of acceleration (i.e. “Yes”), the transmitting terminal  100  may simply end the procedure without transmitting the MAC frame. 
         [0056]    In contrast, as a result of the determination in step S 2 , if the value of the measured acceleration does not exceed the critical value of acceleration (i.e. “No”), the transmitting terminal  100  adds the value of the measured acceleration to an AV field of the MAC frame and broadcasts the MAC frame to its surrounding receiving terminals  201  in step S 4 . 
         [0057]    Here, the transmission of the MAC frame in step S 3  is controlled using one of an automatic mode for processing the frame in a MAC layer and a manual mode for processing the frame in a routing protocol layer. 
         [0058]      FIG. 5  is a functional block diagram illustrating a configuration of a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention. 
         [0059]    Referring to  FIG. 5 , the system  200  for setting an ad-hoc network for a terminal includes a storage unit  210 , an acceleration field searcher  220 , an acceleration comparator  230  and a reception frame processor  240 . Also illustrated in  FIG. 5  is a plurality of surrounding receiving terminals  101 . For sake of convenience, only six surrounding receiving terminals are illustrated and each of the surrounding receiving terminals is labeled as a terminal  101 . However, this illustration is not to be considered limiting in that more or fewer terminals may surround the system  200  and the surrounding terminals need not be identical. 
         [0060]    The storage unit  210  may store a critical value of acceleration of a receiving terminal  200 . 
         [0061]    The acceleration field searcher  220  searches for the AV field of a MAC frame received from any transmitting terminal  101  and determines a value of the AV field of the MAC frame of the transmitting terminal  101 . 
         [0062]    The acceleration comparator  230  compares the value of the AV field determined by the acceleration field searcher  220  with the critical value of acceleration. In an exemplary embodiment, the critical value of acceleration is pre-stored in the storage unit  210 . Alternatively, the critical value may be input by a user or may be received from a system administrator and may have different values depending on system parameters such as the number of surrounding terminals, channel conditions, conditions of the terminal and the like. 
         [0063]    Further, the reception frame processor  240  discards the received MAC frame if the value of the AV field searched by the acceleration field searcher  220  is greater than the critical value of acceleration. 
         [0064]    The reception frame processor  240  may use one of an automatic mode for processing the frame in a MAC layer and a manual mode for processing the frame in a routing protocol layer. 
         [0065]    The following description of the aforementioned components will be oriented to operation associated with the subject matter of the present invention, instead of typical functions and operation. 
         [0066]    The acceleration field searcher  220  searches for the AV field of a MAC frame received from any transmitting terminal  101  and determines a value of the AV field of the MAC frame of the transmitting terminal  101 . 
         [0067]    The acceleration comparator  230  compares the value of the AV field determined by the acceleration field searcher  220  with a critical value of acceleration. 
         [0068]    In an exemplary embodiment, the critical value of acceleration is pre-stored in the storage unit  210 . 
         [0069]    If the value of the AV field determined by the acceleration field searcher  220  is greater than the critical value of acceleration, the reception frame processor  240  discards the received MAC frame. 
         [0070]    In contrast, if the value of the AV field searched by the acceleration field searcher  220  is equal to or less than the critical value of acceleration, the reception frame processor  240  provides the received MAC frame to a higher layer. Of course, if the MAC frame was transmitted without a value in the AV field, the reception frame processor  240  also discards the received MAC frame. 
         [0071]    The reception frame processor  240  may use one of an automatic mode for processing the frame in a MAC layer, and a manual mode for processing the frame in a routing protocol layer. 
         [0072]      FIG. 6  is a flowchart illustrating a method of controlling a system for setting an ad-hoc network for a terminal according to an exemplary embodiment of the present invention. 
         [0073]    Referring to  FIG. 6 , the acceleration field searcher  220  searches the AV field of a MAC frame received from any transmitting terminal  101  and determines a value of the AV field of the MAC frame of the transmitting terminal  101  in step S 100 . 
         [0074]    The acceleration comparator  230  determines whether the value of the AV field determined by the acceleration field searcher  220  is greater than a critical value of acceleration in step S 200 . 
         [0075]    As a result of the determination in step S 200 , if the value of the AV field determined by the acceleration field searcher  220  is greater than the critical value of acceleration, the reception frame processor  240  discards the received MAC frame in step S 300 . Step S 300  may be carried out using an automatic mode for processing the frame in a MAC layer or a manual mode for processing the frame in a routing protocol layer. 
         [0076]    In contrast, if the value of the AV field determined by the acceleration field searcher  220  is equal to or less than the critical value of acceleration, the reception frame processor  240  provides the received MAC frame to a higher layer in step S 400 . Although not illustrated, if in step S 100  it is determined that the AV field does not include an acceleration value, the reception frame processor  240  may proceed to step S 300  and discard the received MAC frame. While the invention has been shown and described in connection with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.