Abstract:
A super frame structure supporting a mesh network, and a beacon scheduling method. The super frame structure and the beacon scheduling method may support a mesh topology in a beacon enabled mode, may have an algorithm that is simple and easily realized via beacon scheduling using a distribution method, and may easily adapt to changes in a network environment.
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:
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:
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:
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:
Provided are a remote control method of a sensor node for low-power and a sensor network therefor. The remote control method, including: generating an interrupt signal when a node receives a remote control signal from a corresponding micro radio frequency (RF) processor installed in a gateway; regenerating the interrupt signal when the node is not converted from a sleep mode to a wake-up mode; collecting sensing data by communicating with other nodes when the node is converted from the sleep mode to the wake-up mode; and converting from the wake-up mode into the sleep mode when the communication is completed.
Abstract:
There is provided a method for optimal data transmission for improving a data transmission rate of a node with variable transmission power in a multi-hop wireless network, the method including the steps of: obtaining channel state information about a current wireless channel of the node; calculating a carrier sensing range in the number of hops using the obtained channel state information, a target signal-to-interference ratio, and a contention window size in order to minimize data collision; calculating the number of nodes attempting data transmission based on signals received from neighbor nodes, the number of the nodes attempting data transmission being the number of contention nodes; and setting transmission power adaptively according to the calculated carrier sensing range value and the contention node numbers and transmitting data with the set of transmission power.
Abstract:
Provided are an apparatus and method for collecting shopping information using a magnetic sensor. The shopping information collecting apparatus, includes: a magnetic value sensing and analyzing means for sensing and analyzing a magnetic value within own zone in real-time; a central processing means for processing shopping information based on the magnetic value analyzed by the magnetic value sensing and analyzing means; and a shopping information transmitting means for transmitting shopping information processed by the central processing means.
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.