Abstract: There are provided an adaptive collision avoidance apparatus and a method in a channel-hopping based wireless AD-HOC networks. The adaptive collision avoidance apparatus is configured to include a channel quality measuring unit that measures the quality of each channel by using receiving frames; an unavailable channel classifying unit that classifies unavailable channels not to perform communications in the future based on information on the quality of each channel; an unavailable channel propagating unit that transfers a list of unavailable channels classified as unavailable channels to adjacent nodes; and a transceiver that transmits and receives frames through channels not classified as the unavailable channels.

Abstract: Disclosed are an apparatus and method for constant amplitude encoding of a transmission signal in a CDM (Code Division Multiplexing) communication system. The apparatus for constant amplitude encoding of a transmission signal includes: an encoding module sequentially performing horizontal encoding and vertical encoding on an input signal; and a spreading and multiplexing module spreading the signal which has been encoded by the encoding module and multiplexing the spread signal in a vertical direction to output a data stream having a constant amplitude.

Abstract: Disclosed are a sensor node having a self localization function and a self localization method of the sensor node. The sensor node calculates a location thereof by receiving location information measured at each of two mobile nodes at different times and using four location information of the received location information. Additional cost and power consumption required for installing additional equipment such as an anchor node, a ultrasonic transceiver and a signal amplifier are reduced.

Abstract: A decentralized scheduling method in a wireless ad hoc network is provided which includes grouping nodes in the network cluster by cluster, determining a cluster head of each cluster, and sequentially performing scheduling cluster by cluster. Accordingly, it is possible to provide an efficient cluster-based scheduling method which quickly adapts to changes and reduces power consumption.

Abstract: The present invention provides a time synchronization method in a low energy critical infrastructure monitoring network and a coordinate access method using a superframe. According to the exemplary embodiments of the present invention, time synchronization can be promptly and efficiently performed in the low energy critical infrastructure monitoring network, a link access method with three grades of link access can be provided, and a frame structure and a process for link generation, link management, and extended connection are provided.

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: Provided is a resource allocation method performed in a wireless network formed of a plurality of nodes, the resource allocation method including the operations of forming clusters and electing cluster heads respectively for the clusters; determining whether a node from among the plurality of nodes forming the wireless network is an edge node; if the node is not the edge node according to a result of the determining, collecting link information related to other nodes in a cluster that comprises the node, and delivering the link information to a cluster head of the cluster; and if the node is the edge node according to a result of the determining, otherwise, obtaining link information and scheduling information from an edge node of another cluster within a communication range with the cluster comprising the edge node, and delivering the link information and scheduling information to the cluster head.

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: Disclosed are an apparatus and a method for configuring a personal space using a virtual switch and more particularly, an apparatus and a method for configuring a personal space providing an integrated service supporting a person by virtually integrating devices interworked with a heterogeneous communication network using a virtual switch. The exemplary embodiment of the present invention implements virtual switching by adding a configuration for interworking between devices connecting to different communication networks to an upper rank of a network layer as an adaptation layer. The exemplary embodiment of the present invention can configure an optimal environment in a personal space and thus, rapidly implement personal services.

Abstract: Provided is an apparatus and method for allocating a synchronous time slot of a low-power wireless personal area network (WPAN) that allocates and controls a time slot based on synchronization in the low-power WPAN. A method of allocating a time slot by a communication node may minimize energy consumption and processing load associated with a message exchange since access to and release from a network may be possible without exchanging a message for controlling access between a coordinator and a device, may access a device in motion within a coordinator region by minimizing accessing time, and may enhance utilization of a time slot by optimally distributing links for accessing devices to available time slots uniformly using information of device global IDs.

Abstract: Provided is a method of determining an operation mode of a node in an ad hoc network. The method includes: monitoring a measured amount of residual energy of the node and comparing the measured amount of residual energy of the node with an amount of residual energy theoretically calculated for the node; identifying an amount of information in a queue included in the node; calculating a relay probability of the node by reflecting the identified amount of information in the queue and the result of comparing the measured amount of residual energy of the node with the theoretically calculated amount of residual energy for the node; and determining the operation mode of the node to be one of a relay mode and a transmission mode, based on the calculated relay probability of the node. The method enables nodes to exchange information about their respective amounts of residual energy and analyze the information without using additional resources and processes.

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 constant amplitude decoding apparatus and method for multiplexed direct-sequence spread spectrum communication system are provided. The constant amplitude decoding apparatus includes: a despreading and demultiplexing module receiving a data stream of a constant amplitude and despreading and demultiplexing the received data stream to restore it to a 2D signal; a decoding module first performing a vertical decoding on the 2D signal and then performing horizontal decoding thereon; a control module determining whether to repeatedly perform vertical decoding and horizontal decoding; and a bit stream information output module outputting the decoding results from the decoding module as a bit stream.

Abstract: There are provided an adaptive collision avoidance apparatus and a method in a channel-hopping based wireless AD-HOC networks. The adaptive collision avoidance apparatus is configured to include a channel quality measuring unit that measures the quality of each channel by using receiving frames; an unavailable channel classifying unit that classifies unavailable channels not to perform communications in the future based on information on the quality of each channel; an unavailable channel propagating unit that transfers a list of unavailable channels classified as unavailable channels to adjacent nodes; and a transceiver that transmits and receives frames through channels not classified as the unavailable channels.

Abstract: Provided is a method and system for managing an identification (ID) of a widely moved sensor node. The method includes recognizing, at a gateway, a node to check an ID of the node, allocating an ID of the gateway as the ID of the node when the ID of the node checked by the gateway is null, sending the ID of the node to a management server when the ID of the node checked by the gateway is not null and is different from the ID of the gateway, and when a new ID is received from the management server, allocating the new ID as the ID of the node.

Abstract: There is provided a mesh routing method in beacon-enabled wireless AD-HOC networks that includes: broadcasting, by nodes constituting a wireless AD-HOC network, a beacon message loading neighbor node information on a beacon payload; managing, by a node receiving the broadcasted beacon message, its own neighbor node table by extracting the neighbor node information loaded on the beacon payload; and performing, by a source node attempting to transmit data or commands, mesh routing on the basis of its own neighbor node table.

Abstract: A hybrid virtual multiple-input multiple-output (V-MIMO) transmission method of a management node in a wireless ad-hoc network in which a transmission path from a source node to a destination node is divided into one or more sections is provided. The hybrid V-MIMO transmission method includes obtaining one or more pieces of node information of one or more nodes by transmitting an information request message to the nodes in response to a transmission request message for data transmission from the source node to the destination node; setting a shortest path (SP) from the source node to the destination node based on the obtained node information; determining transmission schemes individually for nodes present on the SP; issuing a transmission preparation request by transmitting the determined transmission schemes to the respective corresponding nodes; and transmitting a transmission start message to the source node in response to transmission ready responses from the respective nodes.

Abstract: Provided is a method for operating a network node in a specific cluster of a tree-structured network based on distributed address assignment. In the method, a non-registered node is detected. A routing depth of the network node is determined. When the determined routing depth corresponds to a reference value, a sub cluster using a cluster address is generated, and the detected non-registered node is registered as a child node in the generated sub cluster using an internal address.

Abstract: Provided is a method for operating a network node of a tree-structured network based on distributed address assignment. Addresses are assigned. It is determined whether a routing depth of the network node corresponds to a reduced node depth. It is determined whether an authority for generating an inferior node exists using the assigned address when the routing depth of the network node corresponds to the reduced node depth. The inferior node is generated using a result of the determination.

Abstract: Disclosed are an apparatus and method for constant amplitude encoding of a transmission signal in a CDM (Code Division Multiplexing) communication system. The apparatus for constant amplitude encoding of a transmission signal includes: an encoding module sequentially performing horizontal encoding and vertical encoding on an input signal; and a spreading and multiplexing module spreading the signal which has been encoded by the encoding module and multiplexing the spread signal in a vertical direction to output a data stream having a constant amplitude.