Energy-Efficient Data Access Using Spatial Index in the Wireless Data Broadcast for Location-Dependent Healthcare Services

Abstract

The wireless broadcast of spatial data related to healthcare can provide any number of clients with various location-dependent healthcare services. The wireless spatial data broadcast is a strong alternative for the ubiquitous data access, satisfying the scalability and location dependency. In order to elevate the energy efficiency in the broadcast, we propose an air index, the Two-Tier Index for Multiple channels (TTIM). The proposed TTIM lets the clients process the spatial window query energy-efficiently in data broadcasting by the non-flat way. TTIM allows the clients to save energy consumption when they try to access hot and regular data items simultaneously on the broadcast channel. To reach the goal, TTIM distinguishes hot and regular data items with a two-tier grid and broadcasts hot and regular data separately over different channels. With the scheme, TTIM removes the redundant replication of regular data near hot items as the same number broadcasting with hot data items in the existing indexes. That makes the clients' access time shorter by lessening the broadcast cycle length. Also, TTIM shows its strength in the case the clients search regular data and hot ones simultaneously by adopting multiple channels because the separation each other over different channels makes the data waiting time for regular data items shorter compared to using a single channel. Through intensive simulations, we depict that TTIM makes the shorter access time and less energy consumption than other indexes.