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In this paper, the effective bandwidth expansion schemes are investigated to improve the performance of energy efficiency for the Orthogonal Frequency Division Multiplexing (OFDM) wireless communication systems. Three Improved Energy Efficient Bandwidth Expansion (IEEBE) schemes are proposed to assign the available system bandwidth for users. With an exhausted method, the energy efficient Bandwidth Expansion Coefficient (BEC) can be found. Thus the energy efficient performance of the IEEBE is superior to the Same Bandwidth Expansion (SBE). Three methods of pairs, grouping and two-layer grouping are proposed to effectively find the BEC for users based on IEEBE. Simulation results show that two-layer grouping (TLG) outperforms the other two methods and improves Energy Reduction Factor (ERF) by 8.9 % to the SBE. |
