Abstract:
The present invention relates to a random access method capable of improving connection probability in random connection by departmentalizing slot state information in a frame to transmit data and differently selecting a randomly connecting slot according to priority of input traffic. After a plurality of copy packets including mutual location information is transmitted, the packet in which collision is generated is restored by using an interference removing method. The randomly selected slot is differed according to the priority of the traffic by departmentalizing the slot state after removing the interference.
Abstract:
The present invention relates to a time division multiple access (TDMA) frame structure for avoiding the probability of a collision between nodes on an ad-hoc network and a method for assigning a dynamic time slot to a node using the same. The TDMA frame structure according to the present invention comprises a plurality of repeated subframes which comprise a signaling period composed of control signals for data transmission and a data period for transmitting data, wherein the signaling period comprises: a request mini slot whereby a transmission node to transmit data requests slot allocation; an information mini slot for delivering slot information used by a node in a corresponding subframe and slot information on a 1-hop neighbor node; a suggestion mini slot for suggesting, to a neighbor node, a time slot to be allocated to the transmission node by using the information collected from the information mini slot; and a reply mini slot for replying to time slot allocation suggested by the transmission node in the suggestion mini slot.
Abstract:
The present invention relates to a new method for compensating a position error by adjusting transmission intervals of navigation signals from reference stations, which calculates an accurate position of a receiver using navigation signals transmitted from a plurality of reference terminals without using a separate position compensating system at a receiving terminal. In order to accomplish this, disclosed is a method for compensating a position error by adjusting transmission intervals of navigation signals from reference stations comprising: a receiving step which periodically receives navigation signals from at least four reference terminals, wherein positions of the reference terminals on earth are known; a synchronizing step which performs a synchronous control for periodically synchronizing time among reference terminals; an error calculating step during which the respective reference terminals compare a position calculation value using the navigation signal received during the receiving step with an actual coordinate values to calculate a position error; a transmitting step which generates a navigation signal for calculating the position of the receiving terminal by reflecting the position error calculated in the error calculating step and retransmits the navigation signal; and a position calculating step which receives the navigation signal transmitted during the transmitting step and calculates a position.
Abstract:
The present invention relates to a guard time control method though propagation delay estimation and time synchronization acquisition and, more specifically, to a guard time control method through time synchronization acquisition, and propagation delay estimation and time synchronization acquisition, for reducing guard time by acquiring time synchronization between respective nodes and estimating a propagation delay between nodes having adjacent time slots in a single-hop distributed TDMA environment. To this end, disclosed is a guard time control method though propagation delay estimation and time synchronization acquisition, which includes an initialization mode step for calculating a propagation delay value between respective nodes as each node transmits information on the transmission time thereof and information on the time of receiving a packet from the previous node when transmitting a packet according to the order of transmission in an environment where the order of transmission for the respective nodes is predetermined and the nodes are not time-synchronized; and a normal mode step for applying a guard time value corresponding to the propagation delay value as each node transmits the information on the transmission time thereof and the propagation delay value between itself and a node having the next time slot, which was calculated in the initialization mode step, when transmitting the packet according to the order of transmission.
Abstract:
본 발명은 통신 네트워크에서 랜덤 액세스 기법을 이용한 데이터 전송 방법에 관한 것으로, 보다 상세하게는 복제된 데이터 패킷의 수를 제어하는 위성 네트워크의 슬랏 예약 방식을 활용하여, 통신 네트워크에서의 랜덤 액세스를 구현하는 방법 및 장치에 관한 것이다. 상기와 같은 목적을 달성하기 위해서, 본 발명의 일 실시 예에 따른 랜덤 액세스 기법을 이용한 데이터 전송 방법은 한 프레임 주기 동안 통신 채널을 수신하여 슬랏의 점유 상태를 판정하는 단계; 하나 이상의 빈 슬랏을 선택하고 각각의 빈 슬랏에 데이터 패킷을 복제하여 전송하는 단계; 복제된 데이터 패킷 중 다른 데이터 패킷과 충돌이 일어나지 않은 패킷이 수신된 슬랏을 식별하는 단계; 상기 식별된 슬랏 중 어느 하나를 예약 슬랏으로 결정하는 단계를 포함한다.