Abstract:
PURPOSE: A rendezvous channel determination method in a multi-channel access network and apparatus thereof are provided to rapidly connect one channel with desired node by using a distributed channel rendezvous method. CONSTITUTION: A memory unit(20) stores a rendezvous channel determination algorithm. A CPU(Central Processing Unit)(10) reads the rendezvous channel determination algorithm. A radio wave transmission and reception unit(30) transmits searching results to the CPU by searching rendezvous channels through the rendezvous channel determination algorithm. The CPU determines the rendezvous channels according to the searching results. The radio wave transmission and reception unit uses the determined rendezvous permutations by applying the distributed channel rendezvous method.
Abstract:
The present invention relates to a method and a system for promptly detecting a primary user during random transmission of a secondary user in an OFDM-based cognitive radio. The method of the present invention includes the steps of: transmitting, by a secondary user transmission terminal having a first antenna and a second antenna, an OFDM-based cognitive radio signal through the first antenna by regularly inserting a null symbol in a certain length into a predefined single carrier in multiple carriers; receiving and detecting, by the secondary user transmission terminal, a PU signal which is a carrier signal received from a primary user terminal through the second antenna in a null symbol section; and suspending, by the secondary user transmission terminal, the transmission of the OFDM-based cognitive radio signal transmitted through the first antenna if the PU signal is detected. According to the present invention, the method and the system can promptly detect a channel signal of a primary user by fewer overheads and fewer additional devices than the existing primary user detection method.
Abstract:
무선랜의 분산조정함수에 의한 경쟁을 통해 획득된 순방향 순서 암시 정보를 이용한 데이터 전송 방법 및 이를 이용하여 데이터를 전송하는 무선통신기기가 개시된다. 그 순방향 순서 암시 정보를 이용한 데이터 전송 방법은 제1 단말이 제1 전송라운드에서 DCF 경쟁을 통해 데이터 전송에 성공하는 단계 제1전송라운드에 연속하는 제 2전송라운드에서 DCF 경쟁을 통해 제2단말이 데이터 전송에 성공하는 단계 제2전송라운드에서 PIFS 동안 전송 채널이 비어 있을 경우 제1단말은 제2전송라운드에서 진행 중인 시퀀스의 마지막 단말을 선임 단말로 확인하는 단계 제1단말은 확인된 선임 단말에 이어 DCF 경쟁 없이 채널 사용권을 획득하는 순방향 순서 암시가 설정되는 단계 및 제1단말은 순방향 순서 암시 설정에 의해 DCF 경쟁 없이 확인된 선임단말에 이어 데이터를 전송하는 단계를 포함한다. 본 발명에 의하면, DCF에 의한 경쟁에서 백오프 슬롯과 충돌을 획기적으로 줄일 수 있으며, 기존의 DCF 보다 높은 전송률을 제공한다. 또한 순방향 순서 암시 정보가 단말들에서 분산적으로 작동할 수 있기 때문에 추가적인 제어 메시지로 인한 오버헤드가 없고, AP나 DCF를 사용하는 무선 네트워크에서도 기존의 단말들과 통신이 가능하다.
Abstract:
Disclosed are a data transmission method using backward ordering information obtained by distributed coordination function contention in a wireless local area network and a wireless communication device for transmitting data using the same. A data transmission method using the backward ordering information comprises a step of enabling a first terminal to transmit data through distributed control function of a wireless local area network; a step of enabling a second terminal to recognize the first terminal which transmits the data; a step of enabling the second terminal to transmit the data through DCF contention in a successive transmission round after the first terminal transmits data in the one transmission round; a step of enabling the second terminal to confirm the first terminal as a selected terminal; and a step of enabling the second terminal to transmit data without the DCF contention when the first terminal transmits the data with the DCF contention. According to the present invention, the method may remarkably reduce a collision with a back-off slot in the DCF contention and provides a higher transmission rate than the existing DCF. Therefore, overhead is not generated with an additional control message because the backward ordering information is separately operated in the terminals. The method may communicate with the existing terminals in a wireless network using AP or the DCF. [Reference numerals] (AA) Start; (BB) End; (S100) First terminal succeeds transmission through DCF competition; (S110) Second terminal recognizes the transmission success of a first terminal; (S120) Second terminal succeeds transmission in a successive transmission round through DCF competition; (S130) Second terminal confirms a first terminal as an earlier terminal; (S140) Second terminal succeeds transmission without DCF competition when a first terminal succeeds transmission through the DCF competition
Abstract:
PURPOSE: A fast optimal discrete bit-loading method for OFDM-based systems is provided to satisfy overall energy limitation and a target data transmission rate. CONSTITUTION: An optimal bit by channels which satisfy the target data transmitting rate and an energy limitation are allocated by using a water-filling solution(S1-S5). An optimal bit is compared with a maximum bit allocation allowance(S6-S11). The comparison process is performed in order to satisfy the maximum bit allocation allowance limitation by channels. By using the Prior variable so that the extra bit satisfy the goal data transfer rate it is allocated(S12-S16).
Abstract:
본 발명은 모바일 센서 네트워크에서의 다중 커버 레이어링 방법에 대한 것으로서, 보다 상세하게는 모바일 센서 네트워크에 구비된 각 이동 노드들이 임의의 그룹을 선택한 후 이웃한 노드들의 그룹정보를 수집하여 각 그룹에 위치한 노드들의 통계정보를 획득하고, 이 통계정보에 의해 지역적으로 균등한 그룹을 형성할 수 있는 적절한 그룹으로 이동하여 재그룹을 형성함으로써 센서 네트워크 전체적으로 효율적인 분산 레이어링을 수행할 수 있게 한 모바일 센서 네트워크에서의 다중 커버 레이어링 방법에 관한 것이다. 센서 네트워크, 노드, 다중, 커버, 레이어링
Abstract:
PURPOSE: A multi cover layering method in a mobile sensor network is provided to make regional balance of nodes distributed in a target region while changing a group to which neighbor nodes belong through statistics of the group. CONSTITUTION: Nodes select one of K groups by uniform probability(S100). The nodes are respectively located in the selected group. Group information is transmitted and received between the nodes(S210). A node number of a group of a corresponding node is compared with a node number average of all groups(S220). When the node number of the group of the corresponding node is higher than the node number average of all groups, the corresponding node changes the group of the corresponding node(S230).
Abstract:
The present invention relates to a method for discovering a neighbor node using an adaptive and asynchronous rendezvous protocol in an opportunistic network and a portable communication device using the same, the method for discovering a neighbor node includes: a step that each of nodes in the opportunistic network selects a primary number (p) greater than 2; a step that the each of nodes generates a wake-up pattern using the selected primary number; and a step that the each of nodes discovers a neighbor node according to the generated wake-up pattern. According to the present invention, the method is adaptive to requirements such as its own energy state and delay, has no necessity to be synchronized with neighbor nodes, is capable of discovering a neighbor node with the minimum discovery energy and is capable of saving energy for discovering. [Reference numerals] (AA) Start; (BB) End; (S200) Nodes in an opportunistic network selects a prime number greater than 2; (S220) Generating a wake-up pattern using the equation 2 using the selected prime number; (S240) Discovering a neighbor node according to the generated wake-up pattern