Abstract: Disclosed is an RTS/CTS handshaking method for improving the efficiency of wireless communication resources. An RTS/CTS handshaking method according to one example of the present invention comprises the steps of: if a Ready to Send (RTS) packet is received, setting a first Network Allocation Vector (NAV) during a predetermined Clear to Send (CTS) packet transmission period; and if the CTS packet is received, setting a second NAV during a predetermined data packet transmission period.

Abstract: Disclosed is an RTS/CTS handshaking method for improving the efficiency of wireless communication resources. An RTS/CTS handshaking method according to one example of the present invention comprises the steps of: if a Ready to Send (RTS) packet is received, setting a first Network Allocation Vector (NAV) during a predetermined Clear to Send (CTS) packet transmission period; and if the CTS packet is received, setting a second NAV during a predetermined data packet transmission period.

Abstract: A coexistence communication method for broadband power line communication that allocates a resource of another heterogeneous system to a blank resource in data where a plurality of heterogeneous systems are allocated to time division multiplex units (TDMUs) in a distribution scheme and a system therefor are provided. The method includes detecting a blank resource according to a heterogeneous system which does not share a power line among a plurality of heterogeneous systems, from data in which the plurality of heterogeneous systems which share the power line to perform power line communication are allocated to a plurality of TDMUs and in which each TDMU is allocated to a plurality of time division multiplex slots (TDMSs) sorted over time in a distribution scheme and allocating added another heterogeneous system to the blank resource.

Abstract: A coexistence communication method for broadband power line communication that allocates a resource of another heterogeneous system to a blank resource in data where a plurality of heterogeneous systems are allocated to time division multiplex units (TDMUs) in a distribution scheme and a system therefor are provided. The method includes detecting a blank resource according to a heterogeneous system which does not share a power line among a plurality of heterogeneous systems, from data in which the plurality of heterogeneous systems which share the power line to perform power line communication are allocated to a plurality of TDMUs and in which each TDMU is allocated to a plurality of time division multiplex slots (TDMSs) sorted over time in a distribution scheme and allocating added another heterogeneous system to the blank resource.

Abstract: Disclosed is an RTS/CTS handshaking method for improving the efficiency of wireless communication resources. An RTS/CTS handshaking method according to one example of the present invention comprises the steps of: if a Ready to Send (RTS) packet is received, setting a first Network Allocation Vector (NAV) during a predetermined Clear to Send (CTS) packet transmission period; and if the CTS packet is received, setting a second NAV during a predetermined data packet transmission period.

Abstract: Disclosed is a technology for performing a communication using an ultrasonic wave in an environment where an electromagnetic shielding is so severe that a wireless communication using an electromagnetic is difficult. In the environment where the electromagnetic shielding is severe, an ultrasonic terminal according to the present invention may transmit the ultrasonic wave using a solid structure as a medium, and an ultrasonic base station may receive the ultrasonic wave using the solid structure as the medium.

Abstract: Disclosed is a binary signal modulator for minimizing deterioration of receiving performance caused by phase error. The binary signal modulator receives binary signals, and converts the binary signals into complex symbols according to a predetermined mapping relation. Here, the mapping relation is generated when a plurality of mapping symbols are arranged on a plurality of trajectories so that the distance between the mapping symbols is greater than or equal to a predetermined distance and the phase between the mapping symbols is greater than or equal to a predetermined angle from among the trajectories starting from a plurality of points on the complex plane, and a distance between the trajectories is greater than or equal to the minimum distance from among the distances between the points.

Abstract: A resource allocation method in orthogonal frequency division multiple access wireless systems includes: setting, for each of terminals, data transmission factors including a resource location selection scheme; and determining, for each frame, locations of resources to be allocated to the terminals in a resource allocation order by using the resource location selection schemes. Determining the locations of the resources includes: setting the resource allocation order for the terminals according to priorities of the terminals; selecting resources to be allocated to a terminal by using the resource location selection scheme for the terminal; determining whether all or some of the selected resources have been already allocated to other terminals; and allocating the selected resources to the terminal, if it is determined that the selected resources have not been already allocated to other terminals.

Abstract: A Handover method in a mobile WiMAX network includes sending a list of target BSs for possible HO acquired by an MSS to a serving BS; providing, at the serving BS, a HO request to the target BSs in the list along with an unique identifier identifying the MSS to collect association responses from the target BSs; providing, at the serving BS, the association responses along with the unique identifier to the MSS so that the MSS performs scanning and ranging processes; performing resource reservation for possible HO at the target BSs; setting up service flows at a target BS selected among the target BSs; bi-casting data from the serving BS to the MS and the selected target BS before the connection break with the serving BS; and performing, at the MSS, an initializing procedure to connect with the selected target BS as a new serving BS.

Abstract: Provided is a method for switching a piconet device to a coordinator in a piconet. The method receives the latest order of precedence as the next PNC information from the current PNC. Thereafter, the method detects a P-CTA allocated to devices of the piconet using a beacon of a superframe received from the PNC. On failing to receive a beacon from the PNC, the method detects whether “beacon non-receipt” indicating information that is transmitted between piconet devices during the detected P-CTA. If the “beacon non-receipt” indicating information is not detected, the method does not perform a PNC appropriation operation. If the “beacon non-receipt” indicating information is detected, the method determines that the PNC has left the piconet without performing a normal PNC handover procedure and thus performs a PNC appropriation operation according to the order of precedence information.

Abstract: A Handover method in a mobile WiMAX network includes sending a list of target BSs for possible HO acquired by an MSS to a serving BS; providing, at the serving BS, a HO request to the target BSs in the list along with an unique identifier indentifying the MSS to collect association responses from the target BSs; providing, at the serving BS, the association responses along with the unique identifier to the MSS so that the MSS performs scanning and ranging processes; performing resource reservation for possible HO at the target BSs; setting up service flows at a target BS selected among the target BSs; bi-casting data from the serving BS to the MS and the selected target BS before the connection break with the serving BS; and performing, at the MSS, an initializing procedure to connect with the selected target BS as a new serving BS.

Abstract: A resource allocation method in orthogonal frequency division multiple access wireless systems includes: setting, for each of terminals, data transmission factors including a resource location selection scheme; and determining, for each frame, locations of resources to be allocated to the terminals in a resource allocation order by using the resource location selection schemes Determining the locations of the resources includes: setting the resource allocation order for the terminals according to priorities of the terminals; selecting resources to be allocated to a terminal by using the resource location selection scheme for the terminal; determining whether all or some of the selected resources have been already allocated to other terminals; and allocating the selected resources to the terminal, if it is determined that the selected resources have not been already allocated to other terminals.

Abstract: Disclosed is a binary signal modulator for minimizing deterioration of receiving performance caused by phase error. The binary signal modulator receives binary signals, and converts the binary signals into complex symbols according to a predetermined mapping relation. Here, the mapping relation is generated when a plurality of mapping symbols are arranged on a plurality of trajectories so that the distance between the mapping symbols is greater than or equal to a predetermined distance and the phase between the mapping symbols is greater than or equal to a predetermined angle from among the trajectories starting from a plurality of points on the complex plane, and a distance between the trajectories is greater than or equal to the minimum distance from among the distances between the points.

Abstract: Provided is a method for switching a piconet device to a coordinator in a piconet. The method receives the latest order of precedence as the next PNC information from the current PNC. Thereafter, the method detects a P-CTA allocated to devices of the piconet using a beacon of a superframe received from the PNC. On failing to receive a beacon from the PNC, the method detects whether “beacon non-receipt” indicating information that is transmitted between piconet devices during the detected P-CTA. If the “beacon non-receipt” indicating information is not detected, the method does not perform a PNC appropriation operation. If the “beacon non-receipt” indicating information is detected, the method determines that the PNC has left the piconet without performing a normal PNC handover procedure and thus performs a PNC appropriation operation according to the order of precedence information.

Abstract: A multimedia data streaming server for effectively changing a transmit rate of multimedia data according to a network bandwidth that irregularly changes, and a method thereof are provided. The multimedia data streaming server includes a data storing unit, a monitoring unit, and a transmit rate controller. The data storing unit stores the multimedia data according to transmission levels, and the monitoring unit regularly monitors a network bandwidth state of a network streaming the multimedia data. The transmit rate controller increases the transmission level of the multimedia data to a default level if the network bandwidth state is getting bad while transmitting the multimedia data. Then, the transmit rate controller gradually increases or decreases the transmission level of the multimedia data from the default level gradually according to the network bandwidth state.