I. INTRODUCTION
With the spread of smartphones and the development of
wireless technology, data communication is increasingly
important than voice communication. Users of mobile
devices want ubiquitous connectivity to the Internet and
obtain query results in text, image, or video clips. Current
implementation of data search on mobile devices exhibits
many obstacles for conveniently displaying local data. For
example, it is very hard to search information when the user
does not provide a location-based keyword such as the name
of the street or building. To address this issue, location-based
services (LBS) have been developed, which search for
information pertinent to user’s vicinity based on the user’s
location.