Wireless sensor networks have often been used to monitor and report the locations of moving objects. Since sensors can also be used for storage, a wireless sensor network can be considered a distributed database, enabling us to update and query the location information of moving objects. Many researchers have studied the problem of how to construct… (More)
In this paper, we first propose a method, ABVCap, to construct a virtual coordinate system in a wireless sensor network. ABVCap assigns each node multiple 5-tuple virtual coordinates. Subsequently, we introduce a protocol, ABVCap routing, to route packets based on the ABVCap virtual coordinate system. ABVCap routing guarantees packet delivery without the… (More)
—In many applications, it is a basic operation for the sink to periodically collect reports from all sensors. Since the data gathering process usually proceeds for many rounds, it is important to collect these data efficiently, that is, to reduce the energy cost of data transmission. Under such applications, a tree is usually adopted as the routing… (More)
—A wireless sensor network has unidirectional links because sensors can have different transmission ranges, sensors have unstable transmission ranges, and a hidden terminal problem exists. In this paper, we introduce a virtual coordinate assignment protocol (ABVCap Uni) to assign virtual coordinates to nodes that have no geographic information in wireless… (More)
－This paper proves that deploying sensors on grid points to construct a wireless sensor network that fully covers critical grids using minimum sensors (Critical-Grid Coverage Problem) and that fully covers a maximum total weight of grids using a given number of sensors (Weighted-Grid Coverage Problem) are each NP-Complete.
—Because the global positioning system (GPS) consumes a large amount of power and does not work indoors, many virtual-coordinate-based routing protocols are proposed for wireless sensor networks in which geographic location information is unavailable. Each of them, however, cannot guarantee packet delivery or constructs a virtual coordinate system with a… (More)