Abstract:

In wireless environment，the increases in the number of users and the demand for a higher rate have triggered rapidly booming energy consumption at the base station.Therefore，energy efficient design in wireless network has become very essential.An energy efficient multi-user OFDM downlink resource allocation scheme was studied，using the distributed way.Firstly，according to user’s average channel gain and the minimum requirements of user’s bits，subcarriers were allocated，combined with the idea of proposed energy-efficient criterion.Then better channels were assigned to each user in accordance with each user’s allocated subcarrier numbers.Again each user’s average bits were assigned on the user’s allocated subcarriers and optimal adjustment using energy-efficient criterion had to be made to ensure the minimum power.The simulation results show that under the conditions of satisfying bit-error rate and transmission rate for users，the power can be reduced by 5～6 dB in the proposed algorithm，compared with the power in the static frequency division multiple access resource allocation.Furthermore，the power can be reduced by 2～4 dB，compared with the power in a existing classical distributed algorithm.

Key words: energy efficient, multi-user OFDM, minimum power, distributed algorithm