Abstract:
PURPOSE: A multicast data transmission system utilizing location information in a wireless ad-hoc network and data transmission method thereof are provided to prevent the creation of overlapped data and to promote network performance by effectively utilizing wireless resources. CONSTITUTION: A source node acquire information of neighbor nodes(S10). The source node selects one or more intermediate nodes locates one hop distance with the source node(S20). The source node selects the intermediate node which locates to the direction of a destination node as one or more relay nodes for transmitting data(S30). The intermediate node is selected based on the location information of the destination node and the location information of the intermediate node. The intermediate node transmits the data received from the source node to the destination node(S40). [Reference numerals] (AA) Start; (BB) End; (S10) A source node acquire information of neighbor nodes; (S20) A source node selects intermediate nodes; (S30) A source node selects the intermediate node and transmits data to a relay node by considering directivity; (S40) Each relay node transmits data to the destination node by transmitting the data to the relay node of a next hop
Abstract:
A system and a method for estimating the number of tags and preventing tag collision are provided to recognize an RFID(Radio Frequency IDentification) tag quickly by estimating the number of RFID tags correctly in an RFID system, transmitting an RF signal in an FSA(Framed-Slotted ALOHA) mode based on the estimated number of RFID tags, and separating the colliding RFID tags in a binary tree mode. A recognizer(10) transmits an instruction message to RFID tags and receives information from the RFID tags, and a collision manager(11) recognizes collision among the RFID tags and calculates a collision probability of the RFID tags. A tag quantity estimator(12) estimates the number of RFID tags by using the collision probability. A reader controller(13) generates the instruction message, sets the size of a frame used for a recognition process depending on the number of RFID tags, and enables an RFID reader(100) to recognize the RFID tag. The RFID performing an RFID recognition process by dividing the process into a tag quantity estimation process and a recognition process, recognizes the RFID tags in a FSA mode by using the estimated number of RFID tags, and recognizes the colliding tag in a binary tree mode when collision occurs.
Abstract:
본발명은채널상태와이동성을갖는 RFID 태그를고려한충돌방지시스템및 방법에관한것이다. 더욱상세하게는, 컨베이어벨트에서작동하는 RFID 시스템에서 RFID 태그가이동할때 RFID 리더와 RFID 태그사이의거리의변화등에의해가변적인채널상태를반영하여 RFID 태그의이동에의해 RFID 태그와 RFID 리더의거리가가까워졌을때 RFID 태그를빠르게인식하기위한채널상태와이동성을갖는 RFID 태그를고려한충돌방지시스템및 방법에관한것이다. 본발명은상기기술적과제를달성하기위해개시된기술의측면으로, 이동하는다수의 RFID 태그, 그리고 RFID 리더를포함하는 RFID 리더로의인식충돌방지시스템에있어서, 상기 RFID 리더는, 이동하는상기다수의 RFID 태그상호간의충돌방지위해상기다수의 RFID 태그로부터수신된 RN16과이에대한 ACK에포함된 RN16의일치하지않는경우충돌로판단하여충돌이발생안 한 RFID 태그에대해우선순위로전송순서를결정하는 1단계처리모듈, 그리고, 상기 1단계에서결정된전송순서를이용해정보를전송하는 2단계처리모듈을포함하는충돌방지시스템을제공한다.