摘要:
A method for reducing power consumption in a wireless sensor network is provided. An optimized path destined for a sink node is set using a common channel in which first and second nodes use a CSMA scheme. A first channel is set and transmission/reception slots for packet transmission/reception arc allocated in the first channel. A packet is transmitted to the second node through a first transmission slot using a TDMA scheme. When a packet is not received from the second node through a first reception slot within a first set amount of time, the first reception slot is allowed to transition to an inactive state. The first node is one of the sink node, at least one parent node, and at least one child node of the parent node, and the second node is one of child nodes of the first node.
摘要:
A frame structure for piconet master node on/off scheduling and method thereof. The frame structure includes a schedule-based data period, a contention-based active period, a schedule-based schedule notification message period directly following the contention-based active period, and an inactive sleep mode period positioned before the schedule-based data period, before or after the contention-based active period, or after the schedule-based schedule notification message period.
摘要:
A server for providing a traffic image to a user device includes a location information receiving unit which receives information relating to a respective location of each of a plurality of vehicles, a location management unit which receives information relating to a particular area from a user device, and which detects at least one vehicle located within the particular area based on the location information, an information sending unit which sends information relating to the at least one detected vehicle to the user device, an image requesting unit which receives information relating to a vehicle selected from among the at least one detected vehicle from the user device, and which requests, from a device installed in the selected vehicle, transmission of a traffic image of the selected vehicle, and an image providing unit which receives the image and which provides the traffic image to the user device.