The rapidly-increasing high data rate wireless networks and the fast-growing smartphone techniques are continually changing our daily behaviors and coloring our life. However, in order to fully experience the high rate broadband multimedia services, prolonging the battery life of user equipment is critical for the mobile users, especially for the smartphone users. In this work, the problem of offloading the cellular data via a collaborative mobile cloud in an energy efficient manner is investigated. The CMC is formed by a group of users interested in downloading the same content from the operator. Through Device-to-Device communications, the users inside CMC are able to cooperate during downloading procedure and offload data from Base Station for other CMC members. When considering wireless power transfer and MIMO wireless channel, an efficient algorithm is presented to address how to optimally schedule the data offloading and radio resources to obtain the energy efficiency as well as fairness among mobile users. Specifically, the proposed framework takes energy saving maximization, Quality of Service (QoS) requirement as well as user fairness into consideration. Performance evaluations demonstrate that significant energy saving gain can be achieved by the proposed data offloading scheme.