Large proliferation of mobile phone applications result in extensive use of data intensive services such as multimedia download and social network communication. With limited penetration of 3G/4G networks in developing countries, it is common to use low bandwidth 2G services for data communication, resulting in larger download time and correspondingly high power consumption. In this paper, we present a system architecture, Unity, that enables collaborative downloading across co-located peers.

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... ity uses short range radio interfaces such as Bluetooth/WiFi for local coordination, while the actual content is downloaded using a cellular connection. Unity is designed to support mobile phones with diverse capabilities. End-to-end implementation and evaluation of Unity on Android based phones, with varying workload sizes and number of peers, show that Unity can result in multifold increase in download rate for the co-located peers. We also describe architecture of cloud-based Unity which uses principles of mobility prediction, social interactions, and opportunistic networking to make collaboration more pervasive and useful.