In this paper,we propose the Two-way Deep Reinforcement Learning(DRL)-Based resource allocation algorithm,which solves the problem of resource allocation in the cognitive downlink network based on the underlay mode.Se...In this paper,we propose the Two-way Deep Reinforcement Learning(DRL)-Based resource allocation algorithm,which solves the problem of resource allocation in the cognitive downlink network based on the underlay mode.Secondary users(SUs)in the cognitive network are multiplexed by a new Power Domain Sparse Code Multiple Access(PD-SCMA)scheme,and the physical resources of the cognitive base station are virtualized into two types of slices:enhanced mobile broadband(eMBB)slice and ultrareliable low latency communication(URLLC)slice.We design the Double Deep Q Network(DDQN)network output the optimal codebook assignment scheme and simultaneously use the Deep Deterministic Policy Gradient(DDPG)network output the optimal power allocation scheme.The objective is to jointly optimize the spectral efficiency of the system and the Quality of Service(QoS)of SUs.Simulation results show that the proposed algorithm outperforms the CNDDQN algorithm and modified JEERA algorithm in terms of spectral efficiency and QoS satisfaction.Additionally,compared with the Power Domain Non-orthogonal Multiple Access(PD-NOMA)slices and the Sparse Code Multiple Access(SCMA)slices,the PD-SCMA slices can dramatically enhance spectral efficiency and increase the number of accessible users.展开更多
In this paper,we investigate the performance of commensal ambient backscatter communications(AmBC)that ride on a non-ortho go nal multiple access(NOMA)downlink transmission,in which a backscatter device(BD)splits part...In this paper,we investigate the performance of commensal ambient backscatter communications(AmBC)that ride on a non-ortho go nal multiple access(NOMA)downlink transmission,in which a backscatter device(BD)splits part of its received signals from the base station(BS)for energy harvesting,and backscatters the remaining received signals to transmit information to a cellular user.Specifically,under the power consumption constraint at BD and the peak transmit power constraint at BS,we derive the optimal reflection coefficient at BD,the optimal total transmit power at BS,and the optimal power allocation at BS for each transmission block to maximize the ergodic capacity of the ambient backscatter transmission on the premise of preserving the outage performance of the NOMA downlink transmission.Furthermore,we consider a scenario where the BS is restricted by a maximum allowed average transmit power and the reflection coefficient at BD is fixed due to BD’s low-complexity nature.An algorithm is developed to determine the optimal total transmit power and power allocation at BS for this scenario.Also,a low-complexity algorithm is proposed for this scenario to reduce the computational complexity and the signaling overheads.Finally,the performance of the derived solutions are studied and compared via numerical simulations.展开更多
In recent years, non-orthogonal multiple access(NOMA) has attracted a lot of attention as a novel and promising power-domain us-er multiplexing scheme for Long-Term Evolution(LTE) enhancement and 5G. NOMA is able to c...In recent years, non-orthogonal multiple access(NOMA) has attracted a lot of attention as a novel and promising power-domain us-er multiplexing scheme for Long-Term Evolution(LTE) enhancement and 5G. NOMA is able to contribute to the improvement ofthe tradeoff between system capacity and user fairness(i.e., cell-edge user experience). This improvement becomes in particularemphasized in a cellular system where the channel conditions vary significantly among users due to the near-far effect. In this arti-cle, we provide an overview of the concept, design and performance of NOMA. In addition, we review the potential benefits and is-sues of NOMA over orthogonal multiple access(OMA) such as orthogonal frequency division multiple access(OFDMA) adoptedby LTE, and the status of 3GPP standardization related to NOMA.展开更多
图形处理器(Graphics Process Unit,GPU)作为整个手机系统及芯片(System On Chip,SoC)的重要组成部分,除了具有提供高性能的图形图像处理能力之外,减少功耗也是移动平台图形处理器设计者们需要考虑的关键问题之一。在经典图形处理器芯...图形处理器(Graphics Process Unit,GPU)作为整个手机系统及芯片(System On Chip,SoC)的重要组成部分,除了具有提供高性能的图形图像处理能力之外,减少功耗也是移动平台图形处理器设计者们需要考虑的关键问题之一。在经典图形处理器芯片的基础上,一种新的低功耗高性能的图形绘制解决方案着重从架构层面解决功耗的问题。通过显卡驱动端的配合,将很多通用手机应用程序的三维绘制任务转换成低功耗绘制命令,绕开复杂的指令执行单元高效的完成绘制任务,同时通过将整个指令执行单元划分在独立的电源域,进行电源门控,将功耗大大降低。实验表明,对某些典型应用场景,新的解决方案最多可以节省50%的功耗。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61971057).
文摘In this paper,we propose the Two-way Deep Reinforcement Learning(DRL)-Based resource allocation algorithm,which solves the problem of resource allocation in the cognitive downlink network based on the underlay mode.Secondary users(SUs)in the cognitive network are multiplexed by a new Power Domain Sparse Code Multiple Access(PD-SCMA)scheme,and the physical resources of the cognitive base station are virtualized into two types of slices:enhanced mobile broadband(eMBB)slice and ultrareliable low latency communication(URLLC)slice.We design the Double Deep Q Network(DDQN)network output the optimal codebook assignment scheme and simultaneously use the Deep Deterministic Policy Gradient(DDPG)network output the optimal power allocation scheme.The objective is to jointly optimize the spectral efficiency of the system and the Quality of Service(QoS)of SUs.Simulation results show that the proposed algorithm outperforms the CNDDQN algorithm and modified JEERA algorithm in terms of spectral efficiency and QoS satisfaction.Additionally,compared with the Power Domain Non-orthogonal Multiple Access(PD-NOMA)slices and the Sparse Code Multiple Access(SCMA)slices,the PD-SCMA slices can dramatically enhance spectral efficiency and increase the number of accessible users.
基金supported in part by the National Key R&D Program of China under Grant 2018YFE0100500the National Natural Science Foundation of China under Grant 61871387,Grant 61861041,and Grant 61871471+2 种基金the Natural Science Basic Research Program of Shaanxi under Grant 2019JM-019Academy of Finland via:(a)ee-Io T project n.319009,(b)FIREMAN consortium CHIST-ERA/n.326270,and(c)Energy Net Research Fellowship n.321265/n.328869the NUDT Research Fund under Grant ZK17-03-08。
文摘In this paper,we investigate the performance of commensal ambient backscatter communications(AmBC)that ride on a non-ortho go nal multiple access(NOMA)downlink transmission,in which a backscatter device(BD)splits part of its received signals from the base station(BS)for energy harvesting,and backscatters the remaining received signals to transmit information to a cellular user.Specifically,under the power consumption constraint at BD and the peak transmit power constraint at BS,we derive the optimal reflection coefficient at BD,the optimal total transmit power at BS,and the optimal power allocation at BS for each transmission block to maximize the ergodic capacity of the ambient backscatter transmission on the premise of preserving the outage performance of the NOMA downlink transmission.Furthermore,we consider a scenario where the BS is restricted by a maximum allowed average transmit power and the reflection coefficient at BD is fixed due to BD’s low-complexity nature.An algorithm is developed to determine the optimal total transmit power and power allocation at BS for this scenario.Also,a low-complexity algorithm is proposed for this scenario to reduce the computational complexity and the signaling overheads.Finally,the performance of the derived solutions are studied and compared via numerical simulations.
文摘In recent years, non-orthogonal multiple access(NOMA) has attracted a lot of attention as a novel and promising power-domain us-er multiplexing scheme for Long-Term Evolution(LTE) enhancement and 5G. NOMA is able to contribute to the improvement ofthe tradeoff between system capacity and user fairness(i.e., cell-edge user experience). This improvement becomes in particularemphasized in a cellular system where the channel conditions vary significantly among users due to the near-far effect. In this arti-cle, we provide an overview of the concept, design and performance of NOMA. In addition, we review the potential benefits and is-sues of NOMA over orthogonal multiple access(OMA) such as orthogonal frequency division multiple access(OFDMA) adoptedby LTE, and the status of 3GPP standardization related to NOMA.
文摘图形处理器(Graphics Process Unit,GPU)作为整个手机系统及芯片(System On Chip,SoC)的重要组成部分,除了具有提供高性能的图形图像处理能力之外,减少功耗也是移动平台图形处理器设计者们需要考虑的关键问题之一。在经典图形处理器芯片的基础上,一种新的低功耗高性能的图形绘制解决方案着重从架构层面解决功耗的问题。通过显卡驱动端的配合,将很多通用手机应用程序的三维绘制任务转换成低功耗绘制命令,绕开复杂的指令执行单元高效的完成绘制任务,同时通过将整个指令执行单元划分在独立的电源域,进行电源门控,将功耗大大降低。实验表明,对某些典型应用场景,新的解决方案最多可以节省50%的功耗。
