In this paper,we optimize the spectrum efficiency(SE)of uplink massive multiple-input multiple-output(MIMO)system with imperfect channel state information(CSI)over Rayleigh fading channel.The SE optimization problem i...In this paper,we optimize the spectrum efficiency(SE)of uplink massive multiple-input multiple-output(MIMO)system with imperfect channel state information(CSI)over Rayleigh fading channel.The SE optimization problem is formulated under the constraints of maximum power and minimum rate of each user.Then,we develop a near-optimal power allocation(PA)scheme by using the successive convex approximation(SCA)method,Lagrange multiplier method,and block coordinate descent(BCD)method,and it can obtain almost the same SE as the benchmark scheme with lower complexity.Since this scheme needs three-layer iteration,a suboptimal PA scheme is developed to further reduce the complexity,where the characteristic of massive MIMO(i.e.,numerous receive antennas)is utilized for convex reformulation,and the rate constraint is converted to linear constraints.This suboptimal scheme only needs single-layer iteration,thus has lower complexity than the near-optimal scheme.Finally,we joint design the pilot power and data power to further improve the performance,and propose an two-stage algorithm to obtain joint PA.Simulation results verify the effectiveness of the proposed schemes,and superior SE performance is achieved.展开更多
Cognitive radio is able to share the spectrum with primary licensed user,which greatly improves the spectrum efficiency.We study the optimal power allocation for cognitive radio to maximize its ergodic capacity under ...Cognitive radio is able to share the spectrum with primary licensed user,which greatly improves the spectrum efficiency.We study the optimal power allocation for cognitive radio to maximize its ergodic capacity under interference outage constraint.An optimal power allocation scheme for the secondary user with complete channel state information is proposed and its approxi-mation is presented in closed form in Rayleigh fading channels.When the complete channel state in-formation is not available,a more practical transmitter-side joint access ratio and transmit power constraint is proposed.The new constraint guarantees the same impact on interference outage prob-ability at primary user receiver.Both the optimal power allocation and transmit rate under the new constraint are presented in closed form.Simulation results evaluate the performance of proposed power allocation schemes and verify our analysis.展开更多
allocation （PA） plays an important role in capacity improvement for cooperative multiple-input multipleoutput （Co-MIMO） systems. Many contributions consider a total power constraint （TPC） on the sum of transmit ...allocation （PA） plays an important role in capacity improvement for cooperative multiple-input multipleoutput （Co-MIMO） systems. Many contributions consider a total power constraint （TPC） on the sum of transmit power from all nodes in addressing PA problem. However, in practical implementations, each transmit node is equipped with its own power amplifier and is limited by individual power constraint （IPC）. Hence these PA methods under TPC are not realizable in practical systems. Meanwhile, the PA problem under IPC is essential, but it has not been studied. This paper extends the traditional non-cooperative water-filling PA algorithm to IPC-based Co-MIMO systems. Moreover, the PA matrix is derived based on the compound channel matrix from all the cooperative nodes to the user. Therefore, the cooperative gain of the IPC-based Co-MIMO systems is fully exploited, and further the maximal instantaneous capacity is achieved. Numerical simulations validate that, under the same IPC conditions, the proposed PA scheme considerably outperforms the non-cooperative water-filling PA and uniform PA design in terms of ergodic capacity.展开更多
Coordinated multi-point transmission/reception （CoMP） was proposed currently as an effective technology to improve cell-edge throughput in next-generation wireless systems. Most of the existing work discussed cluste...Coordinated multi-point transmission/reception （CoMP） was proposed currently as an effective technology to improve cell-edge throughput in next-generation wireless systems. Most of the existing work discussed clustering methods mostly to maximize the edge user throughput while neglecting the problem of energy efficiency, such as those algorithm clustering base stations （BSs） of better channel condition and BSs of worse channel condition together. In addition, BSs usually increase the transmit power to achieve higher throughput without any considering of interference caused to other users, that may result in energy waste. The authors focus on the throughput maximizing problem while fully considering energy saving problem in CoMP systems. A coefficient is defined to describe the fitness of clusters. Then a sub-carrier allocation algorithm with clustering method is put forward for CoMP downlink, which can save the transmit power of BS and increase the throughput. Furthermore a power allocation scheme is proposed based on non-cooperation game; in which the transmit power is decreased by BSs generally to reach the Nash equation （NE）. Simulation shows that the proposed sub-carrier allocation scheme and power allocation algorithm are better than the existing ones on users＇ throughput while consumes much less energy.展开更多
针对认知异构蜂窝网络的上行资源分配问题,提出了基于带宽和功率约束的资源分配算法,并使用改进的群智能算法求解.根据认知无线电技术特性推导出认知家庭用户的带宽和功率分配取值范围,在满足用户服务质量(Quality of Services,QoS)的...针对认知异构蜂窝网络的上行资源分配问题,提出了基于带宽和功率约束的资源分配算法,并使用改进的群智能算法求解.根据认知无线电技术特性推导出认知家庭用户的带宽和功率分配取值范围,在满足用户服务质量(Quality of Services,QoS)的前提下将更多的资源分配给其他用户,以提升网络中用户的传输需求和缓解网络上行接入负载的压力.针对樽海鞘群算法存在收敛精度低、收敛慢等缺陷,将疯狂算子和动态精英学习因子分别引入领导者和跟随者中,以提升算法寻优效率和寻优精度.将改进的樽海鞘群算法求解基于带宽和功率约束的资源分配算法.仿真实验表明,引入带宽和功率约束的资源分配算法能有效提升网络性能,且在保证用户QoS条件下,能有效提升系统效益和用户接入公平性.展开更多
基金supported by the Fundamental Research Funds for the Central Universities of NUAA(No.kfjj20200414)Natural Science Foundation of Jiangsu Province in China(No.BK20181289).
文摘In this paper,we optimize the spectrum efficiency(SE)of uplink massive multiple-input multiple-output(MIMO)system with imperfect channel state information(CSI)over Rayleigh fading channel.The SE optimization problem is formulated under the constraints of maximum power and minimum rate of each user.Then,we develop a near-optimal power allocation(PA)scheme by using the successive convex approximation(SCA)method,Lagrange multiplier method,and block coordinate descent(BCD)method,and it can obtain almost the same SE as the benchmark scheme with lower complexity.Since this scheme needs three-layer iteration,a suboptimal PA scheme is developed to further reduce the complexity,where the characteristic of massive MIMO(i.e.,numerous receive antennas)is utilized for convex reformulation,and the rate constraint is converted to linear constraints.This suboptimal scheme only needs single-layer iteration,thus has lower complexity than the near-optimal scheme.Finally,we joint design the pilot power and data power to further improve the performance,and propose an two-stage algorithm to obtain joint PA.Simulation results verify the effectiveness of the proposed schemes,and superior SE performance is achieved.
基金Supported by the National Natural Science Foundation of China (No. 60972008)
文摘Cognitive radio is able to share the spectrum with primary licensed user,which greatly improves the spectrum efficiency.We study the optimal power allocation for cognitive radio to maximize its ergodic capacity under interference outage constraint.An optimal power allocation scheme for the secondary user with complete channel state information is proposed and its approxi-mation is presented in closed form in Rayleigh fading channels.When the complete channel state in-formation is not available,a more practical transmitter-side joint access ratio and transmit power constraint is proposed.The new constraint guarantees the same impact on interference outage prob-ability at primary user receiver.Both the optimal power allocation and transmit rate under the new constraint are presented in closed form.Simulation results evaluate the performance of proposed power allocation schemes and verify our analysis.
基金supported by the International Scientific and Technological Cooperation Program (S2010GR0902)the National Natural Science Foundation of China (61001119, 61027003)
文摘allocation （PA） plays an important role in capacity improvement for cooperative multiple-input multipleoutput （Co-MIMO） systems. Many contributions consider a total power constraint （TPC） on the sum of transmit power from all nodes in addressing PA problem. However, in practical implementations, each transmit node is equipped with its own power amplifier and is limited by individual power constraint （IPC）. Hence these PA methods under TPC are not realizable in practical systems. Meanwhile, the PA problem under IPC is essential, but it has not been studied. This paper extends the traditional non-cooperative water-filling PA algorithm to IPC-based Co-MIMO systems. Moreover, the PA matrix is derived based on the compound channel matrix from all the cooperative nodes to the user. Therefore, the cooperative gain of the IPC-based Co-MIMO systems is fully exploited, and further the maximal instantaneous capacity is achieved. Numerical simulations validate that, under the same IPC conditions, the proposed PA scheme considerably outperforms the non-cooperative water-filling PA and uniform PA design in terms of ergodic capacity.
基金supported by the National Hi-Tech Research and Development Program of China(2012AA01A508)
文摘Coordinated multi-point transmission/reception （CoMP） was proposed currently as an effective technology to improve cell-edge throughput in next-generation wireless systems. Most of the existing work discussed clustering methods mostly to maximize the edge user throughput while neglecting the problem of energy efficiency, such as those algorithm clustering base stations （BSs） of better channel condition and BSs of worse channel condition together. In addition, BSs usually increase the transmit power to achieve higher throughput without any considering of interference caused to other users, that may result in energy waste. The authors focus on the throughput maximizing problem while fully considering energy saving problem in CoMP systems. A coefficient is defined to describe the fitness of clusters. Then a sub-carrier allocation algorithm with clustering method is put forward for CoMP downlink, which can save the transmit power of BS and increase the throughput. Furthermore a power allocation scheme is proposed based on non-cooperation game; in which the transmit power is decreased by BSs generally to reach the Nash equation （NE）. Simulation shows that the proposed sub-carrier allocation scheme and power allocation algorithm are better than the existing ones on users＇ throughput while consumes much less energy.
文摘针对认知异构蜂窝网络的上行资源分配问题,提出了基于带宽和功率约束的资源分配算法,并使用改进的群智能算法求解.根据认知无线电技术特性推导出认知家庭用户的带宽和功率分配取值范围,在满足用户服务质量(Quality of Services,QoS)的前提下将更多的资源分配给其他用户,以提升网络中用户的传输需求和缓解网络上行接入负载的压力.针对樽海鞘群算法存在收敛精度低、收敛慢等缺陷,将疯狂算子和动态精英学习因子分别引入领导者和跟随者中,以提升算法寻优效率和寻优精度.将改进的樽海鞘群算法求解基于带宽和功率约束的资源分配算法.仿真实验表明,引入带宽和功率约束的资源分配算法能有效提升网络性能,且在保证用户QoS条件下,能有效提升系统效益和用户接入公平性.
