Database-as-a-Service is becoming more and more popular for many organizations. Storing data on the cloud can significantly reduce costs in terms of maintenance costs and initial investment costs. But due to data privacy and security concerns, many companies are still reluctant to use outsourced database service. In this paper, we present a solution to protect data privacy on the cloud, at the same time, allowing multiple users accessing the shared database with security assurance.

This work presents an all IP based micro-cellular network configuration used in the metropolitan area. It aims to provide high-bit-rate packet transfer to fast-moving terminals. With the high transfer rate and guaranteed security, it can be considered as the extension of corporate LAN for business uses. For avoiding contention based access delay and packet re-transfer delay during handover, a new parallel polling scenario is proposed. Operating within the range of logical macro cell (LMC), detailed packet transfer procedures of polling are explained. Also automatic switching-over of LMC that locate the mobile terminal (MT) at the center cell of LMC all along can reduce the burden of strict time frame faced by the MT during high frequency handover between micro-cells.