Research On Energy Efficiency Optimization Scheme In Distributed Antenna System With SWIPT

The problem of energy consumption in information and communication industry is more and more serious,reducing energy consumption and improving energy efficiency(EE)will be an important direction of 5G in the future.Distributed antenna system(DAS)has been introduced as a key technology for realizing “green communication” in expanding coverage and increasing sum rate of the system.Furthermore,simultaneous wireless information and power transfer(SWIPT)can supply wireless networks with perpetual energy and extend the battery life.So it is of great significance for energy saving and environmental protection.To this end,combining these two technologies to study the EE optimization problem in the DAS-SWIPT system,and present various energy-efficient resource allocation schemes to provide theoretical basis for realizing green distributed antenna system.The main work is summarized as follows.1.The energy-efficient optimization scheme based on SWIPT in DAS is investigated.Firstly,the DAS-SWIPT system model is formulated and the objective problem of maximizing the system EE is given.Then an optimal resource allocation scheme is presented according to the KKT condition and ergodic method.Considering the high complexity of ergodic method,a suboptimal scheme with low complexity is proposed by using antenna selection.Simulation results show that the suboptimal scheme can achieve similar EE performance to the optimal one while reducing the calculation complexity.2.The energy-efficient optimization scheme based on SWIPT in multi-user DAS system is investigated.Firstly,the system model and the corresponding EE optimization problem of multi-user DAS-SWIPT system is formulated,and the original objective optimization problem is transformed into an unconstrained optimization problem by means of fractional programming theory and Lagrange multiplier method.Then we make a joint optimization of power allocation and power splitting ratio of the system by means of the block coordinate descent algorithm and Dinkelbach method,and the corresponding resource allocation scheme is presented.The simulation results show that the EE performance of the proposed scheme is close to the high-complexity ergodic method.3.The energy-efficient optimization scheme based on SWIPT and imperfect channel state information(CSI)in multi-user DAS is investigated.Firstly,an energy-efficient objective optimization problem for multi-user DAS-SWIPT system with imperfect CSI is constructed.Considering it is difficult to calculate the optimization problem directly,the upper bound of theobjective function is obtained according to Jensen inequality.Based on this upper bound,a suboptimal energy-efficient optimization resource allocation scheme based on large-scale fading is presented by means of fractional programming theory.The effectiveness of the proposed scheme is verified by simulation.