An energy efficient hybrid transmission scheme for wireless VoD service under QoS constraints

Video-on-demand service is becoming more and more attractive and it also leads to rapidly rising in energy consumption. Traditional batching transmission scheme can reduce the transmission power consumption but it inevitably causes some delay. On the contrary, traditional patching scheme can provide real time service to meet user requests but it will generate many unicast patching streams when a lot of user requests arrive to the base station simultaneously. In this paper, we extend the previous work and propose a hybrid transmission scheme which is suitable for this condition. In the scheme, user requests are categorized into heterogeneous and homogenous category by base station with different intensity. The responses of heterogeneous requests use unicast media streams and the responses of homogenous requests use a hybrid scheme with both batching and patching. Theoretical derivation for power consumption of this proposed scheme demonstrates that our scheme is better than traditional one in power consumption and we obtain the relationship between the optimization of energy efficiency and the Quality of Service (QoS). Simulation results show that our scheme can bring about 80% and 15% power deduction compared with the traditional unicast scheme and traditional multicast scheme while satisfying the QoS.