In mobile environments, mobile devices move continuously and have limited resources as computation, energy, and memory. Data management is one of the big challenges in this dynamic environment. The use of a context in mobile devices is receiving considerable attention to meet this challenge. In context-aware systems, applications can use the contextual information such as user location, time of day, nearby people and devices, and user activity in useful way to solve some dynamic environments issues. Context retrieval problem is one of the key issues in context awareness computing.