Abstract: A received signal strength indicator is provided. The received signal strength indicator includes a plurality of differential amplifiers forming an amplifier chain for amplifying differential signals and a plurality of rectifiers for rectifying signals output from the plurality of differential amplifiers and the differential signals, and a low pass filter for combining the signals rectified by the plurality of rectifiers to output received signal strength. Each rectifier includes a class AB voltage-current converter for converting a differential voltage into a current, and two triode transistors.

Abstract: A time synchronization method in a wireless sensor network, a low power routing method using a reservation scheme, and an apparatus for performing the method are provided. The time synchronization method in the wireless sensor network may include: receiving a first synchronization request command packet from a parent node that manages time synchronization for a predetermined synchronization region; receiving, from the parent node, a second synchronization request command packet that has a transmission timestamp value of the first synchronization request command packet; and performing time synchronization for a child node based on a reception time of the first synchronization request command packet, a reception time of the second synchronization request command packet, and the transmission timestamp value of the first synchronization request command packet.

Abstract: A wireless communication method using a control channel between wireless communication devices including: exchanging profile information between a node and intermediate relay nodes therearound so as to allow the node to transmit/receive data to/from a destination node; determining, by the node, a first intermediate relay node using the profile information and determining a wireless communication mode with the first intermediate relay node; and transmitting/receiving data between the node and the first intermediate relay node by the determined wireless communication mode is provided.

Abstract: A method of operating a device capable of periodically hopping a predetermined interval using a channel hopping sequence in order to improve low radio frequency (RF) reliability caused by single frequency based channel access.

Abstract: A method and apparatus for encoding a constant amplitude that is applied to a code division multiplexing communication system are provided. By dividing a data bit into a block unit, the receiving side can easily determine an error, and by reducing power consumption in outdoor wide area communication using a bit string of a small length in a basic unit of an input frame, efficiency can be improved, and thus a physical layer of a ubiquitous sensor network can be optimized.

Abstract: A method and apparatus for allocating a management resource of a channel of a node that is included in a wireless personal area network (WPAN) are provided. A resource of a channel performs communication with a specific node using a multi-superframe including a plurality of superframes, limits a position area of a time slot including a channel that is allocated to communication with a specific node to a predetermined superframe of the plurality of superframes, gives a logical connection ID to the time slot, and is allocated by matching the logical connection ID and a management resource that manages the time slot.

Abstract: An end device transmits a request command for requesting a slot management to a coordinator, and receives a reply command including a result of the slot management request from the coordinator. Each of the request command and the reply command includes an allocation order for indicating a slot allocation interval request.

Abstract: A medium access control (MAC) technique of a multihop sensor network. In the multihop sensor network, the MAC technique may contribute to significantly reducing transmission delay, and allow real-time services to be provided to all nodes by extending a guaranteed time slot (GTS) restricted to one hop in a personal area network (PAN) coordinator (PNC) to all nodes. Furthermore, the MAC technique may allow the number of available GTSs to be significantly increased, by using all 16 frequency band channels instead of using only a single frequency band and setting a multi-superframe.

Abstract: Provided are a node device of a beacon-enabled Wireless Personal Area Network (WPAN) managing a channel resource and a method thereof. The node device may generate a pseudo random binary sequence (PRBS) and generate a hopping sequence based on a number of available channels using the PRBS, thereby generating a hopping sequence having a characteristic of pseudo randomness and selecting a channel to be hopped, using the hopping sequence.

Abstract: Provided are a reliability-based, real-time sensor network medium access control (MAC) communication system and method using a superframe. The superframe includes an active duration which is a time duration in which a communication is established, and a sleep duration which is a time duration in which no communication is established. The active duration includes a beacon block in which a plurality of beacon transmission nodes are respectively allocated beacon slots for transmitting a beacon frame, and a forwarding block in which each of sinks nodes is allocated a slot for unifying data regarding the sink node and data regarding sensor nodes managed by the sink node and transmit the result of unifying in order to establish a communication between the sink nodes and between each of the sink nodes and a base station.

Abstract: A distributed channel hopping communication method in a low power wireless ad-hoc network. A beacon transmission and reception scheduling method using a distributed channel hopping method in a wireless ad-hoc network, the method includes: transmitting beacons using channel hopping, before establishing the wireless ad-hoc network including a plurality of nodes having a BP including at least one time slot, and receiving beacons of a plurality of neighboring nodes of each of the plurality of nodes; collecting information about the wireless ad-hoc network and information about the plurality of neighboring nodes from the received beacons; scheduling the receiving of the beacons that are transmitted from the plurality of neighboring nodes in the BP, using TDMA in each of the at least one time slot based on the information about the plurality of neighboring nodes; and scheduling transmitting of a beacon in each of the at least one time slot.

Abstract: A wireless network system using a cyclic frame including a beacon period (BP), a mesh contention access period (MCAP), and a slot period (SP). The cyclic frame has a frame structure that shares a channel hopping sequence of a node, thereby sharing the channel hopping sequence that operates as an existing mesh node without generating an additional channel hopping sequence, and supporting mesh and star type topologies together in order to efficiently operate a network.

Abstract: In a wireless sensor network system including at least one sensor network, when a network message received from a sensor node of a sensor network corresponds to a predetermined service, the wireless sensor network system forms a wireless local area network (WLAN) overlay network which is based on a WLAN system within a service area at which the sensor node is located. Data corresponding to the predetermined service is transmitted and received through the WLAN overlay network.

Abstract: A complex communication apparatus transmits/receives voice information with other complex communication apparatuses through a set voice channel. The complex communication apparatus broadcasts a signaling packet expressing a destination identifier representing a desired communication type of one-to-one communication, group communication, and broadcast communication with other complex communication apparatuses and information of the set voice channel and performs voice communication with a complex communication apparatus corresponding to a destination identifier of other complex communication apparatuses, having received the signaling packet.

Abstract: A slot managing method and apparatus is provided. A first layer of a destination node receives a request command for requesting a slot management from a source node, and transfers a first primitive for reporting a receipt of the request command to a second layer that is an upper layer of the first layer. The second layer transfers a second primitive to the first layer as a response to the slot management request. The first layer broadcasts a reply command including a result of the slot management request to neighboring nodes in response to the second primitive. The source node broadcasts a notify command including a result of the slot management request.

Abstract: A method of operating a device capable of periodically hopping a predetermined interval using a channel hopping sequence in order to improve low radio frequency (RF) reliability caused by single frequency based channel access.

Abstract: Provided is a cross-layer routing method in a wireless sensor network including: locating a destination node which is a final destination of data by a source node which generates the data; and determining an optimal relay node among one or more neighboring nodes using their position information for each hop and forwarding the data from the source node to the destination node through the determined relay nodes. Therefore, an effective and stable routing which reduces overheads of additional control messages used for stable data forwarding and reduces collisions in a shared channel by using wireless link layer characteristics can be implemented.

Abstract: Provided are a node device of a beacon-enabled Wireless Personal Area Network (WPAN) managing a channel resource and a method thereof. The node device may generate a pseudo random binary sequence (PRBS) and generate a hopping sequence based on a number of available channels using the PRBS, thereby generating a hopping sequence having a characteristic of pseudo randomness and selecting a channel to be hopped, using the hopping sequence.

Abstract: A highly precise clock synchronization apparatus in a real-time locating system (RTLS), includes an optical transmitting/receiving unit for receiving a clock information frame from a clock synchronization server, converting the received clock information frame in series-parallel, and transmitting/receiving the clock information data and the clock information; an offset estimation unit for detecting a preamble signal and a clock information signal from the series-parallel converted clock information frame, calculating a phase difference value by comparing the detected preamble signal with the detected clock information signal, and outputting an offset value based on the calculated phase difference value; and a clock synchronization unit for updating a local clock value to a time of the clock synchronization server based on the offset value and the clock information frame.

Abstract: Provided are a reliability-based, real-time sensor network medium access control (MAC) communication system and method using a superframe. The superframe includes an active duration which is a time duration in which a communication is established, and a sleep duration which is a time duration in which no communication is established. The active duration includes a beacon block in which a plurality of beacon transmission nodes are respectively allocated beacon slots for transmitting a beacon frame, and a forwarding block in which each of sinks nodes is allocated a slot for unifying data regarding the sink node and data regarding sensor nodes managed by the sink node and transmit the result of unifying in order to establish a communication between the sink nodes and between each of the sink nodes and a base station.