Pusan National University

Sanghwa Chung

Jaeyoung Kim

Yuvin Ha

Sihyeon Lee

Jeongbae Park

Kihoon Jeon

Minjae Kim

Yunsung Lee

Heejun Lee

An unslotted CSMA/CA optimization device includes a variable initializing unit performing variable initialization used in an algorithm for unslotted CSMA/CA optimization; an exploration and exploitation selecting unit determining exploration/exploitation using an epsilon greedy algorithm; an action selecting unit selecting an action having the best Q-value, among actions, when exploitation is selected, and randomly selecting an action when exploration is selected; a channel information collecting unit executing backoff when an action (backoff time) is selected, repeatedly executing CCA during the backoff time, and counting the number of times a channel is idle and the number of times the channel is busy; a success rewarding unit transmitting a packet when the channel is idle and rewarding success when acknowledge (Ack) is received; and a Q-table updating unit checking the received reward and updating a Q-table based on an action, a state, and a reward.

Unslotted CSMACA optimization method and devices in Wi-SUN using reinforcement learning

Disclosed is a link-based autonomous cell scheduling device including: a routing information manager that records and manages information on a node's preferred parent node and child nodes in a routing information table; a slot frame manager that generates and modifies a number of slot frames by referring to routing information in the routing information table, packet queue information, and transmission/reception result information; a slot frame schedule determiner that integrates a number of slot frames to generate one integrated slot frame corresponding to a global slot frame size and record the same in an integrated slot frame table, by referring to a link unicast slot frame table, a broadcast slot frame table, and an EB slot frame table; and a TSCH MAC layer driver that operates after checking for a cell assigned to the integrated slot frame by referring to the integrated slot frame table at the TSCH MAC layer.

Link-based autonomous cell scheduling device and method for improved traffic throughput in TSCH protocol

Disclosed are fast cell allocation scheduling device and method for a mobile node in a 6TiSCH network, in which when link quality of the mobile node is changed, a fixed path directed to a route node is allocated to establish a movement-route node fixed path minimizing a delay time between the mobile node and the route node.

Fast cell allocation scheduling device and method for mobile node in 6TiSCH network

Disclosed is a device for increasing reliability of downlink traffic to mobility devices in an RPL environment that can increase reliability of downlink traffic by dual path generation and redundant packet retransmission for the mobile device in an environment where mobility exists. The moving device includes a directed acyclic graph (DAG) rank value acquisition unit for receiving a destination oriented directed acyclic graph information object (DIO) of parent devices to obtain a DAG rank value of each parent device; a parent device selection unit for selecting prefer parents and alternate parents based on a DAG rank of the parent device; and a destination advertisement object (DAO) signal processing unit for transmitting a DAO to a sync device when the prefer parents and the alternate parents are determined.

Device and method for increasing reliability of downlink traffic to mobile devices in RPL environment

Disclosed is a device for reverse slot reservation in an industrial low-power wireless network, which includes: a child device configured to send a slot demand of the child device to a parent device through an information element (IE) and a solicitation (SOLICIT) packet included in an enhanced beacon (EB) and configured to select a required number of slots and respond using a Response packet to reserve the slots when an OFFER is received; and a parent device configured to transmit an OFFER packet to a device with the highest priority or a device selected in round-robin order when there is no priority on the basis of slot demands of child devices to start reverse slot reservation and configured to select some slots from among available slots of the parent device, add the selected slots to CellList, and transmit the OFFER packet to a corresponding child device.

Reverse slot reservation method and device in industrial low-power wireless network

Disclosed are a scheduling apparatus and method using a virtual slotframe in an industrial wireless sensor network in which devices on the network generate schedules that are efficient with regard to data traffic having various cycles by performing scheduling in a distributed manner through a virtual slotframe scheme, the scheduling apparatus and method including a packet classifier configured to manage, in a list, a point in time when a packet was generated by referring to a packet transmission record, a transmission record analyzer configured to analyze a traffic pattern on the basis of a list indicating the point in time when the packet was generated, a virtual slotframe schedule generation manager configured to generate a virtual slotframe schedule according to the traffic pattern when the traffic pattern is classified, and a schedule converter and aggregator configured to perform a conversion and an aggregation for a direct link schedule to be used for TSCH (Time Slotted Channel Hopping) operation.

Scheduling apparatus and method using virtual slot frame in industrial wireless network

An apparatus for managing deterministic and synchronous multi-channel extension (DSME) network fluctuations in an industrial wireless sensor network includes: a network congestion rate measurer configured to measure a network congestion rate on the basis of a number of times an association request message is received and a number of times carrier sensing is performed, a DSME-guaranteed time slot (GTS) allocation information collector configured to continuously collect DSME-GTS allocation information using coordinators, a DSME-GTS maintenance determiner configured to determine whether to maintain or collect DSME-GTSs on the basis of collected network information, a slot reallocation determiner configured to determine whether data is received without collision from two nodes to which a slot is redundantly allocated and transmit a DSME-GTS expiration request to a sensor node for reallocation of empty slots.

System and method for managing DSME network fluctuation in industrial wireless sensor network

An apparatus for blacklisting a local channel in an Internet-of-Things (IoT) multi-hop network includes: a local blacklist creator configured to create a blacklist based on channel quality estimation (CQE) value; an energy detection performer configured to transmit a scanned received signal strength indicator (RSSI) value to a non-intrusive channel quality measurer; the non-intrusive channel quality measurer configured to calculate channel quality information and transmit the calculated channel quality information to the local blacklist creator; a nearby neighboring node information manager configured to receive a local blacklist from the local blacklist creator and store the local blacklist with a blacklist of a communication partner node; a frequency selector configured to receive a created link mask from the nearby neighboring node information manager and allow for communication considering the link mask in a case of a dedicated slot.

Apparatus and method for blacklisting local channel in IoT multi-hop network

The present invention provides, on the basis of congestion of a network, an arrangement state of nodes, and a quality of a communication channel, a fast synchronization scheduling apparatus and method for reducing a listening time of a node that desires to join. The fast synchronization scheduling apparatus and method include a radio frequency (RF) transmission and reception module configured to transmit and receive RF signals from nearby channels, a received signal strength indicator (RSSI) reception and storage module configured to receive RSSI values from the RF signals received from the RF transmission and reception module and store the received RSSI values, a channel sorting module configured to measure Channel Quality Estimation (CQE) values of the respective channels by putting the RSSI values of the respective channels received from the RSSI reception and storage module into a CQE formula and to sort the channels in order of highest CQE value (highest channel quality) based on the measured CQE values, and a channel setting and advertisement packet (ADV) reception module configured to receive an input of a channel having the highest CQE value from the channel sorting module, set the channel, and start a listening operation to receive an ADV in the set channel.

Fast synchronization scheduling apparatus and method for time slotted channel hopping in congested industrial wireless network environment

The fast synchronization scheduling apparatus includes: a radio frequency (RF) transmission and reception module configured to transmit and receive RF signals from nearby channels, a received signal strength indicator (RSSI) reception and storage module configured to receive RSSI values from the RF signals received from the RF transmission and reception module and store the received RSSI values, a channel sorting module configured to measure Channel Quality Estimation (CQE) values of the respective channels by putting the RSSI values of the respective channels received from the RSSI reception and storage module into a CQE formula and to sort the channels in order of highest CQE value (highest channel quality) based on the measured CQE values.

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Busan, South Korea

Sanghwa Chung