Shingle-based query indexing for location-based mobile e-commerce

We present a shingle-based query index (SQI) for supporting location-based services in mobile e-commerce. SQI is used to efficiently identify moving objects that are currently located inside a geographical region. A set of virtual shingles is predefined, each with a unique ID. One or more shingles are used to cover the geographical region defined by a range query, where the covering shingles may overlap with one another. SQI maintains a direct mapping from individual shingles to the range queries that contain them. The use of covering shingles has two important properties. First, it does not impose any limit on the object moving speed or direction. Second, it allows the revaluation of continual range queries to capitalize on the incremental changes in object locations. Simulations are conducted to evaluate the effectiveness of SQI and compare it with a cell-based approach.