Abstract: A mobile communication system, including: first and second nodes, wherein the first node includes: a first transmitter and a first receiver, and wherein the second node includes: a second receiver receiving a ranging signal from the first transmitter; a frequency synthesizer generating an internal signal in response to a sensing of the reception of the ranging signal; a digital circuit calculating a beat frequency by comparing the ranging signal to the internal signal and evaluating a time lapse from the reception of the ranging signal until the sensing of the reception of the ranging signal by using the beat frequency, wherein the time lapse is part of a response time of the second node; and a second transmitter providing the first receiver with the ranging signal that includes the response time of the second node.

Abstract: Provided is a method for refining node position information in a wireless sensor network having an ultra wideband communication network and a wireless personal area network where the initial positions of respective nodes are set, by utilizing nodes at a 2-hop distance, or more than a 2-hop distance when the number of neighboring nodes at a 1-hop distance is not sufficient to perform triangulation, and to refine the position of nodes based on a distance measured between the respective nodes. Because the initial position is refined and confirmed in a wireless sensor network, a user node operates as a pseudo anchor node for the nodes which have no anchor node nearby. Furthermore, as a node has the refined position, it can act as a pseudo anchor node and be used to compute the position of the other nodes. Additionally, positions of nodes of the wireless sensor network can be estimated with more accuracy.

Abstract: A time synchronization method in a wireless sensor network, has an upper node that provides back-off scheduling to lower nodes in the wireless sensor network of a hierarchical structure. Each of the lower nodes synchronizes time according to the back-off scheduling based on its local clock. The time synchronous method also allows the number of packets required for synchronization in the wireless sensor network to sharply decrease, and the life time of the network to increase. Additionally, the time synchronous method provides a response packet from a lower node in response to a synchronization packet from an upper node, which is used as a synchronization start packet for secondary lower nodes, so that synchronization in the entire network is rapidly processed.

Abstract: A mobile communication system, including: first and second nodes, wherein the first node includes: a first transmitter and a first receiver, and wherein the second node includes: a second receiver receiving a ranging signal from the first transmitter; a frequency synthesizer generating an internal signal in response to a sensing of the reception of the ranging signal; a digital circuit calculating a beat frequency by comparing the ranging signal to the internal signal and evaluating a time lapse from the reception of the ranging signal until the sensing of the reception of the ranging signal by using the beat frequency, wherein the time lapse is part of a response time of the second node; and a second transmitter providing the first receiver with the ranging signal that includes the response time of the second node.

Abstract: A location recognition system and method using stereophonic sound, the system having a transmitter and a receiver. The transmitter uses the stereophonic sound and transmits location tracking information of an object. The transmitter includes a sound detector which detects a sound of the object and converts the detected sound to an electrical signal; a data converter which converts the electrical signal converted by the sound detector, to acoustic data; and a first communication interface which transmits the acoustic data converted by the data converter and the location tracking information to the receiver. A user can immediately recognize the location of the transmitter which transmits the location tracking information and is the target of the location tracking. Therefore, the mutual communications between the transmitter and the receiver which receives the location tracking information can be smoothly carried out.

Abstract: A time synchronization method in a wireless sensor network, has an upper node that provides back-off scheduling to lower nodes in the wireless sensor network of a hierarchical structure. Each of the lower nodes synchronizes time according to the back-off scheduling based on its local clock. The time synchronous method also allows the number of packets required for synchronization in the wireless sensor network to sharply decrease, and the life time of the network to increase. Additionally, the time synchronous method provides a response packet from a lower node in response to a synchronization packet from an upper node, which is used as a synchronization start packet for secondary lower nodes, so that synchronization in the entire network is rapidly processed.

Abstract: Provided is a method for refining node position information in a wireless sensor network having an ultra wideband communication network and a wireless personal area network where the initial positions of respective nodes are set, by utilizing nodes at a 2-hop distance, or more than a 2-hop distance when the number of neighboring nodes at a 1-hop distance is not sufficient to perform triangulation, and to refine the position of nodes based on a distance measured between the respective nodes. Because the initial position is refined and confirmed in a wireless sensor network, a user node operates as a pseudo anchor node for the nodes which have no anchor node nearby. Furthermore, as a node has the refined position, it can act as a pseudo anchor node and be used to compute the position of the other nodes. Additionally, positions of nodes of the wireless sensor network can be estimated with more accuracy.

Abstract: A shooting game method and an apparatus for a mobile terminal device using local positioning communication to run a shooting game by local positioning communication based on positions of the mobile terminal device and a neighboring mobile terminal device. Accordingly, improving the user convenience implementing an intelligent shooting game using a position recognizing function of the mobile terminal device, and also, instead of a stand-alone game, twosome or more games can be implemented.

Abstract: A method and system for indoor positioning using a mobile terminal, the method including designating a plurality of virtual locations using the mobile terminal while the mobile terminal is in motion; and tracking a location of a specific terminal by performing a localization measurement communication with the specific terminal based on the plurality of virtual anchor locations.

Abstract: A location recognition system and method using stereophonic sound, the system having a transmitter and a receiver. The transmitter uses the stereophonic sound and transmits location tracking information of an object. The transmitter includes a sound detector which detects a sound of the object and converts the detected sound to an electrical signal; a data converter which converts the electrical signal converted by the sound detector, to acoustic data; and a first communication interface which transmits the acoustic data converted by the data converter and the location tracking information to the receiver. A user can immediately recognize the location of the transmitter which transmits the location tracking information and is the target of the location tracking. Therefore, the mutual communications between the transmitter and the receiver which receives the location tracking information can be smoothly carried out.