Research On Dynamic Energy-Efficient Resource Allocation For Ofdm System

Vigorous development of the communication industry in recent years lead to increasing energy consumption and serious pollution.Therefore more and more attention has been paid to "green radio"which aim to optimize communication system to reduce energy consumption.OFDM (Orthogonal Frequency Division Multiplexing)has draw a lot of attention as a key technology of4G system and a basis of frequency division multiple access (OFDMA). In this paper, resource allocation in OFDM system is discussed in order to maximizeenergy efficiency.First, the background and status of wireless communication system based on energy efficiencyresource allocation are introduced. The structure and the key technology of the energy efficient wireless system arepresented after that.Then the structure of OFDM system and classic resource allocation algorithms are analyzed. We notice that the signalling overhead in multi-user system occupies a significant portion of the resources.Wepropose a schemeto reduce signaling overhead and improve energy efficiencybased on analysis above. The proposed schemeupdates the subcarrier allocation(SCA) once a window which consist of continuous time slots. In that case signaling overhead and computation of the system are reduced.System model is constructed to maximize EE of system subject tousers’transmission rate and powerconstraints.In order to reduce algorithm complexity, a two-step allocation algorithm is proposed.Interior pointcutting plane method is developed to allocate subcarriers and an energy-efficient power allocation algorithm is proposed based on subcarriers allocation.Simulation results show that both the energy and spectral efficiency for the proposed scheme are in proximity to the traditional scheme while the control signaling overhead and complexity arelower.