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:
Provided is a method for selecting, by a device, a peer discovery resource (PDR) in a device-to-device (D2D) communication system comprising the steps of: determining a PDR selection range that can be selected by the device; and selecting a PDR in the PDR selection range.
Abstract:
통신시스템(100)은 펨토셀 기지국(HeNB, 130)이 사용할 수 있는 공유 부대역의 수( )를 결정하는 매크로셀 기지국(MeNB, 110) 및 개의 공유 부대역 중에서 기준 거리에 위치한 이웃 HeNB가 사용하는 이웃 공유 부대역을 선택하는 펨토셀 기지국(HeNB, 130)을 포함한다.
Abstract:
The present invention comprises the steps of enabling a base station to obtain channel gain information for at least one D2D communication terminal (DUE) and at least one mobile communication terminal (CUE) located in the coverage of the base station (610); of enabling the base station to determine final transmission power between the mobile communication terminal (CUE) and the D2D communication terminal (DUE) using the channel gain information (620); and of enabling the base station to allocate resources to the selected D2D communication terminal by selecting the D2D communication terminal (DUE) which shares the resources with the mobile communication terminal (CUE) (630). The determination step (620) determines the transmission power of DUE j, in which the sum of the CUE i transmission rate and the DUE j transmission rate is maximized when the base station shares the same resources between the CUE i and the DUE j using the channel gain information, as the optimal transmission power. The allocation step (630) comprises a step of enabling the base station to allocate the resources to CUE i (631); a step of enabling the base station to select the DUE j which becomes the maximum sum of the CUE i among DUE using the determined optimal transmission power; and a step of enabling the base station to enabling the base station to transmit a control signal including resource information allocated to the CUE i and the optimal transmission power for the DUE j to the selected DUE j through a downlink.