Green Resource Allocation to Minimize Receiving Energy in OFDMA Cellular Systems

Advanced cellular systems supporting ultra high traffic (e.g., 1 Gbps) utilize aggressive communication technologies to user equipment (UE) and thus induce high-energy consumption. To reduce UE energy consumption, we note that in OFDMA systems, transmissions to one UE can be scheduled into fewer time slots due to multiple available sub-carriers. It implies that the circuit energy of UEs can be reduced if turning off the circuits during the slots without receptions is allowed. A nonlinear integer resource optimization is thus formulated for base stations to minimize the receiving energy of UEs, with a proposed algorithm to reach optimal solution efficiently. Numerical results demonstrate that our computationally efficient algorithm can easily reduce more than 60% UE energy consumption, and thus is ready for practical systems such as 3GPP LTE/LTE-Advanced.