Abstract:
A method for constructing an IPv6-based overlay network for mobility is provided to construct an overlay network to provide service mobility to terminals in order to offer application-layered continuous services to nodes on the overlay network. The first mobile terminal(A) continuously sends packets to its own base node(B), regardless of the movement of a correspondent terminal, or the second mobile terminal(D). The base node(B) buffers the data packets transmitted from the first mobile terminal(A) until a binding update message is received from the second mobile terminal(D)(S501). The second mobile terminal(D) sends a binding update message to inform the base node(B) that its own address has been changed(S502). The base node(B), receiving the binding update message, sends data packets to the new address of the second mobile terminal(D)(S503). The base node(B) also binds its backup base node(C) to the new address of the second mobile terminal(D)(S504). The second mobile terminal(D) sends a binding list containing the new address to its own base node(E) for synchronization(S505).
Abstract:
A method for saving power in a WLAN access point based on IEEE 802.11 is provided to set a part for turning off a radio to a super frame, and prevent stations from transmitting data to an access point during the part by using a virtual carrier sensing scheme defined in IEEE 802.11 standards, thereby increasing a lifetime of a WLAN access point operating with limited battery power. A method for saving power in a WLAN(Wireless Local Area Network) access point based on IEEE(Institute of Electrical and Electronics Engineers) 802.11 comprises the following steps. A super frame is divided into a listen part(101), a service part(102) and a sleep part(103). In the listen part, data transmitted from a station(12) is received. In the service part, data is transmitted to the station. In the sleep part, a radio is turned off to stay in a sleep state. By transmitting a 'CTS-TO-SELF' frame having a predetermined duration value to the station in the sleep part, the station can recognize that a channel is currently used.
Abstract:
A VHO(Vertical Handoff) method between heterogeneous systems and a method for transmitting and receiving data files using the same are provided to minimize the power consumption of a mobile terminal, increase the utilization of networks, and achieve load balancing by using an energy-effective IEEE 802.11 search algorithm when VHO is executed between an IEEE 802.16e network and an IEEE 802.11 network. If the control part of a mobile terminal acquires the present speed of the mobile terminal(400), the control part compares the acquired value with "vmax"(401). In case the acquired value is larger than vmax, the control part confirms whether the mobile terminal is under communication with an IEEE 802.11 system(405). If so, the control part waits until the communication state ends. Then, if the communication state is completed, the control part turns off an IEEE 802.11 interface module(406). However, if the present speed of the mobile terminal is larger than vmax, the control part receives a MOB_NBR-ADV message broadcasted from an IEEE 802.16e system, extracts IEEE 802.11 WLAN AP installation density information from the received message, and compares it with a reference value(403). If the extracted value is smaller than or equal to the reference value, the control part turns off the IEEE 802.11 interface module(406). If the extracted value is larger than the reference value, the control part turns on the IEEE 802.11 interface module for vertical handoff to an IEEE 802.11 WLAN and searches for a WLAN AP(404).
Abstract:
본 발명은 이기종 시스템 간의 수직 핸드오프 방법 및 그를 이용한 데이터파일 송수신 방법에 관한 것으로, 이기종 시스템 간의 수직 핸드오프(특히, IEEE 802.16e 휴대인터넷망에서 IEEE802.11 무선랜으로의 수직 핸드오프)에 있어서, 모바일 장치의 고속 이동으로 인한 수직 핸드오프의 비효율성을 제거하고, 최소한의 에너지만을 이용하여 타겟 무선랜망(IEEE802.11)을 탐색하며, 또한 과금 모델을 반영하여 서비스 비용을 최소화할 수 있게 하는, 이기종 시스템 간의 수직 핸드오프 방법 및 그를 이용한 데이터파일 송수신 방법을 제공하고자 한다. 이를 위하여, 본 발명은, 휴대인터넷 시스템에서 무선랜 시스템으로의 수직 핸드오프 방법에 있어서, 휴대인터넷의 서비스영역에 있는 모바일 장치가 현재의 이동속도를 획득하여 소정의 임계속도와 비교하는 속도 비교 단계; 상기 속도 비교 결과, 상기 모바일 장치의 이동속도가 상기 임계속도보다 크면, 상기 모바일 장치가 상기 휴대인터넷을 통한 통신을 수행하는 휴대인터넷 이용 단계; 상기 속도 비교 결과, 상기 모바일 장치의 이동속도가 상기 임계속도 이하인 경우, 타켓 무선랜의 액세스포인트(AP) 설치정보에 기초하여 무선랜 탐색 성공률을 판단하여 상기 무선랜 탐색 성공률을 저해하지 않는 범위 내에서 최소탐색빈도를 갖게 하는 탐색 주기로 무선랜 탐색을 수행하는 무선랜 탐색 단계; 및 상기 무선랜 탐색 단계에서 탐색된 무선랜 채널로 수직 핸드오프를 수행하는 핸드오프 단계를 포함한다. 이기종 시스템, 수직 핸드오프, IEEE 802.16e, IEEE 802.11, 휴대인터넷, 무선 랜
Abstract:
A video input/output device is put to a pass mode, and, if the video input/output device secures a still picture, the video input/ output device is put to a obtaining mode. If a pass mode is set, the video input/output device is driven to a pass mode. Then a checking finds whether a picture control sound is received, and, if it is received, the video input/output device is driven to a display mode to disconnect the vocal communication and carry out a receiving procedure by driving a decoding means. If the control sound is not received, a checking finds whether it is a picture transmission, and, if it is a picture transmission, the vocal communication is disconnected to drive the decoding means.