Quick spatial data access using expanded cells in non-flat wireless data broadcast over multiple channels

Abstract

Wireless spatial data broadcasting supports a great number of clients effectively to access location-dependent information. A non-flat broadcasting scheme helps clients quickly access their desired data items by disseminating clients' preferred data items, called hot data, more frequently than others (regular data) in a broadcast cycle. A system adopting non-flat scheme with a single broadcasting channel can cause the data access time of clients long because the length of a broadcasting cycle is lengthened by the replication of hot data. We propose a spatial indexing scheme using expanded grid cells that adopts non-flat broadcasting scheme over multiple channels. The proposed indexing scheme allows clients to access queried data items quickly by reducing the size of the search space for a given query. Also, when clients access hot data and regular data items simultaneously, the proposed indexing scheme reduces the access time because of the reduced length of a broadcasting cycle by adopting multiple channels. Performance evaluation through simulation studies discloses the proposed indexing scheme outperforms existing schemes with respect to the access time.