Context aware energy efficient optimization for video on-demand service over wireless networks

Video on-demand (VOD) service is widely requested, and is becoming a dominant application in wireless networks, where energy efficiency (EE) is a major design goal. Reducing the energy consumption of VOD service with given quality of service (QoS) requirement can improve the EE of wireless systems. Recent finding shows that user mobility is highly predictable, and hence future location information is possible to know. In this paper, we study EE-optimal transmit power and bandwidth allocation for VOD service in orthogonal frequency division multiplexing (OFDM) system by exploiting context information. We consider two kinds of context information, i.e., the predictive average channel gains and the QoS of VOD service. The optimal resource allocation policy that minimizes the average energy consumption for VOD service is proposed. At the beginning of the service, the average transmit power and number of used subcarriers are allocated with future average channel gains. During the procedure of the service, the instantaneous transmit power is allocated to different subcarriers after the instantaneous channel gains becomes available. Simulation results show that the energy consumed for VOD service with the proposed policy is around half of that with an existing policy.