The current existed scheduling schemes which are generally derived from the antenna selection algorithms can improve the sum-rate of MU-MIMO system to some extent.However,these schemes can not make the best of multi-u...The current existed scheduling schemes which are generally derived from the antenna selection algorithms can improve the sum-rate of MU-MIMO system to some extent.However,these schemes can not make the best of multi-user diversity gain,thus incurring capacity loss.To overcome these disadvantages,in this paper,a novel user scheduling scheme based on the lower bound capacity of MU-MIMO broadcast channel is proposed for the multi-user zero-forcing precoding system.In the proposed scheme,the base station will schedule those users that can achieve the maximal lower bound capacity of MU-MIMO system by certain optimal criterion.Simulation results are exhibited to indicate that the proposed scheme can provide performance improvement than other existed scheduling schemes.展开更多
Orthogonal frequency division multiplexing （OFDM） which has been adopted in the long-term evolution （LTE） system can improve the system capacity obviously. However, it also brings about severe inter-cell interfere...Orthogonal frequency division multiplexing （OFDM） which has been adopted in the long-term evolution （LTE） system can improve the system capacity obviously. However, it also brings about severe inter-cell interference （ICI） for cell-edge users （CEUs）. To tackle this problem, multi-user selection and power control （MuS-PC） is proposed as an efficient scheme in uplink coordinated multi-point multi-user multi-input multi-output （CoMP-MU-MIMO） transmission/reception. This paper jointly considers user＇s signal to interference plus noise ratio （S1NR） and proportional fairness （PF） to maximize the total channel capacity in multi-user selection by formulating a penalty function. To simplify the penalty function＇s computation, particle swarm optimization （PSO） algorithm is introduced. In addition, power control is adopted to maximize overall energy efficiency. Simulation results demonstrate that the MuS-PC scheme can not only obtain the optimal total channel capacity while guarantee each user＇s quality of service （QoS） and PF, but also largely reduce computational complexity and improve energy efficiency. As a result, the poor communication quality of CEUs can be enhanced.展开更多
This paper investigates the device-to-device(D2 D) communication underlaying multi-user multi-input multi-output(MU-MIMO) cellular networks. It is assumed that D2 D users reuse the downlink time-frequency resources of...This paper investigates the device-to-device(D2 D) communication underlaying multi-user multi-input multi-output(MU-MIMO) cellular networks. It is assumed that D2 D users reuse the downlink time-frequency resources of cellular links, and the base station(BS) is assumed to be equipped with multiple antennas. We investigate the ergodic achievable sum rate of the system when the interference cancellation(IC) precoding strategy is employed at the BS. The distributions of the received signal-to-interference-plus-noise ratio(SINR) for each link are firstly analyzed, and an exact ergodic achievable sum rate of the whole system with closedform expressions is then derived. Furthermore, we present novel upper and lower bounds with simpler expressions, which are later verified to be fairly close to the Monte-Carlo simulations. All the expressions we presented are suitable for arbitrary network topology and arbitrary number of antennas at BS. Based on the derived bounds, the influence of the antennas at BS on system performance is then analyzed. We reveal that the system performance increases along with the number of antennas at BS in a logarithmic way. The accuracy of our analytical results is validated via comparisons with Monte-Carlo simulations.展开更多
Ultra-reliable and low-latency communication(URLLC)is still in the early stage of research due to its two strict and conflicting requirements,i.e.,ultra-low latency and ultra-high reliability,and its impact on securit...Ultra-reliable and low-latency communication(URLLC)is still in the early stage of research due to its two strict and conflicting requirements,i.e.,ultra-low latency and ultra-high reliability,and its impact on security performance is still unclear.Specifically,short-packet communication is expected to meet the delay requirement of URLLC,while the degradation of reliability caused by it makes traditional physical-layer security metrics not applicable.In this paper,we investigate the secure short-packet transmission in uplink massive multiuser multiple-inputmultiple-output(MU-MIMO)system under imperfect channel state information(CSI).We propose an artificial noise scheme to improve the security performance of the system and use the system average secrecy throughput(AST)as the analysis metric.We derive the approximate closed-form expression of the system AST and further analyze the system asymptotic performance in two regimes.Furthermore,a one-dimensional search method is used to optimize the maximum system AST for a given pilot length.Numerical results verify the correctness of theoretical analysis,and show that there are some parameters that affect the tradeoff between security and latency.Moreover,appropriately increasing the number of antennas at the base station(BS)and transmission power at user devices(UDs)can increase the system AST to achieve the required threshold.展开更多
为了最大化利用大规模多用户MIMO(Multi User-Multi Input and Multi Output,MU-MIMO)系统中的频谱资源和功率资源,在无线专网信道环境下,结合了多用户预编码和块对角化(Block Diagonalization,BD)干扰抑制技术,分别应用了线性检测和非...为了最大化利用大规模多用户MIMO(Multi User-Multi Input and Multi Output,MU-MIMO)系统中的频谱资源和功率资源,在无线专网信道环境下,结合了多用户预编码和块对角化(Block Diagonalization,BD)干扰抑制技术,分别应用了线性检测和非线性检测算法,开发了完整的仿真链路平台,对系统误码率和频谱效率进行了仿真分析。在仿真结果性能接近的3种非线性检测算法中,通过比较其复杂度分析结果,考虑硬件实现难易程度,得出在无线通信专网上行链路系统中应用QRM-MLD(QR Decomposition and M algorithm-Maximum Likelihood Detection,M=2)算法最为合适的结论。展开更多
Utilizing the unlicensed spectrum as supplementary is being studied to meet the increasingly growing demand of user equipment for rate,traffic and bandwidth,and thus to mitigate the current spectrum scarcity crisis.In...Utilizing the unlicensed spectrum as supplementary is being studied to meet the increasingly growing demand of user equipment for rate,traffic and bandwidth,and thus to mitigate the current spectrum scarcity crisis.In this paper,we investigate the uplink multi-user multiple-input multiple-output(UL MU-MIMO) technique to achieve multiplexing gain in unlicensed spectrum.We first define a new parameter called channel busy radio(CBR) which is related to the probability of occupying the unlicensed channel,and find that the failure to occupy the unlicensed channel leads to the performance degradation in unlicensed spectrum.Then,according to the user-specific CBR of the unlicensed channel,we propose a flexible scheduling scheme for UL MU-MIMO in unlicensed spectrum,and formulate an optimization problem for the optimal scheduled user number.Furthermore,an adaptive scheduling algorithm is proposed to decide the optimal number of the scheduled users efficiently.The simulation results show that,based on statistical channel condition in unlicensed spectrum,adjusting the number of the scheduled user flexibly can offset the degraded throughput and form an optimal MU-MIMO transmission.展开更多
基金Sponsored by the Important National Science & Technology Specific Projects of China (Grant No. 2009ZX03004-001)the Cooperation Project with Huawei Technologies Company (Grant No. YBWL2010242)
文摘The current existed scheduling schemes which are generally derived from the antenna selection algorithms can improve the sum-rate of MU-MIMO system to some extent.However,these schemes can not make the best of multi-user diversity gain,thus incurring capacity loss.To overcome these disadvantages,in this paper,a novel user scheduling scheme based on the lower bound capacity of MU-MIMO broadcast channel is proposed for the multi-user zero-forcing precoding system.In the proposed scheme,the base station will schedule those users that can achieve the maximal lower bound capacity of MU-MIMO system by certain optimal criterion.Simulation results are exhibited to indicate that the proposed scheme can provide performance improvement than other existed scheduling schemes.
基金supported by the National Science and Technology Major Project (2011ZX03001-007-03)the National Natural Science Foundation of China (61271182)the Fundamental Research Funds for the Central Universities (2013RC0112)
文摘Orthogonal frequency division multiplexing （OFDM） which has been adopted in the long-term evolution （LTE） system can improve the system capacity obviously. However, it also brings about severe inter-cell interference （ICI） for cell-edge users （CEUs）. To tackle this problem, multi-user selection and power control （MuS-PC） is proposed as an efficient scheme in uplink coordinated multi-point multi-user multi-input multi-output （CoMP-MU-MIMO） transmission/reception. This paper jointly considers user＇s signal to interference plus noise ratio （S1NR） and proportional fairness （PF） to maximize the total channel capacity in multi-user selection by formulating a penalty function. To simplify the penalty function＇s computation, particle swarm optimization （PSO） algorithm is introduced. In addition, power control is adopted to maximize overall energy efficiency. Simulation results demonstrate that the MuS-PC scheme can not only obtain the optimal total channel capacity while guarantee each user＇s quality of service （QoS） and PF, but also largely reduce computational complexity and improve energy efficiency. As a result, the poor communication quality of CEUs can be enhanced.
基金supported by the Natural Science Foundation of Jiangsu Province (No. BK20170758)the National Natural Science Foundation for Young Scholars of China (No. 61701201)+1 种基金the Natural Science Foundation for colleges and universities of Jiangsu Province (No. 17KJB510011)Project of Key Laboratory of Wireless Communications of Jiangsu Province
文摘This paper investigates the device-to-device(D2 D) communication underlaying multi-user multi-input multi-output(MU-MIMO) cellular networks. It is assumed that D2 D users reuse the downlink time-frequency resources of cellular links, and the base station(BS) is assumed to be equipped with multiple antennas. We investigate the ergodic achievable sum rate of the system when the interference cancellation(IC) precoding strategy is employed at the BS. The distributions of the received signal-to-interference-plus-noise ratio(SINR) for each link are firstly analyzed, and an exact ergodic achievable sum rate of the whole system with closedform expressions is then derived. Furthermore, we present novel upper and lower bounds with simpler expressions, which are later verified to be fairly close to the Monte-Carlo simulations. All the expressions we presented are suitable for arbitrary network topology and arbitrary number of antennas at BS. Based on the derived bounds, the influence of the antennas at BS on system performance is then analyzed. We reveal that the system performance increases along with the number of antennas at BS in a logarithmic way. The accuracy of our analytical results is validated via comparisons with Monte-Carlo simulations.
基金supported by the National Key R&D Program of China under Grant 2018YFB1801103the National Natural Science Foundation of China under Grant(no.62171464,no.62122094)。
文摘Ultra-reliable and low-latency communication(URLLC)is still in the early stage of research due to its two strict and conflicting requirements,i.e.,ultra-low latency and ultra-high reliability,and its impact on security performance is still unclear.Specifically,short-packet communication is expected to meet the delay requirement of URLLC,while the degradation of reliability caused by it makes traditional physical-layer security metrics not applicable.In this paper,we investigate the secure short-packet transmission in uplink massive multiuser multiple-inputmultiple-output(MU-MIMO)system under imperfect channel state information(CSI).We propose an artificial noise scheme to improve the security performance of the system and use the system average secrecy throughput(AST)as the analysis metric.We derive the approximate closed-form expression of the system AST and further analyze the system asymptotic performance in two regimes.Furthermore,a one-dimensional search method is used to optimize the maximum system AST for a given pilot length.Numerical results verify the correctness of theoretical analysis,and show that there are some parameters that affect the tradeoff between security and latency.Moreover,appropriately increasing the number of antennas at the base station(BS)and transmission power at user devices(UDs)can increase the system AST to achieve the required threshold.
文摘为了最大化利用大规模多用户MIMO(Multi User-Multi Input and Multi Output,MU-MIMO)系统中的频谱资源和功率资源,在无线专网信道环境下,结合了多用户预编码和块对角化(Block Diagonalization,BD)干扰抑制技术,分别应用了线性检测和非线性检测算法,开发了完整的仿真链路平台,对系统误码率和频谱效率进行了仿真分析。在仿真结果性能接近的3种非线性检测算法中,通过比较其复杂度分析结果,考虑硬件实现难易程度,得出在无线通信专网上行链路系统中应用QRM-MLD(QR Decomposition and M algorithm-Maximum Likelihood Detection,M=2)算法最为合适的结论。
基金partly supported by the NSFC International Cooperation and Exchange Program(Grant No.61461136001)partly supported by the Shanghai Rising-Star Program(grant no.17QA1403800)+2 种基金the NSFC International Cooperation and Exchange Program(Grant No.61461136004)partly supported by the ESEC project of Tekes and the National Natural Science Foundation of China(Grant No.61401440)partly supported by the NSFC International Cooperation and Exchange Program(Grant No.61461136003)
文摘Utilizing the unlicensed spectrum as supplementary is being studied to meet the increasingly growing demand of user equipment for rate,traffic and bandwidth,and thus to mitigate the current spectrum scarcity crisis.In this paper,we investigate the uplink multi-user multiple-input multiple-output(UL MU-MIMO) technique to achieve multiplexing gain in unlicensed spectrum.We first define a new parameter called channel busy radio(CBR) which is related to the probability of occupying the unlicensed channel,and find that the failure to occupy the unlicensed channel leads to the performance degradation in unlicensed spectrum.Then,according to the user-specific CBR of the unlicensed channel,we propose a flexible scheduling scheme for UL MU-MIMO in unlicensed spectrum,and formulate an optimization problem for the optimal scheduled user number.Furthermore,an adaptive scheduling algorithm is proposed to decide the optimal number of the scheduled users efficiently.The simulation results show that,based on statistical channel condition in unlicensed spectrum,adjusting the number of the scheduled user flexibly can offset the degraded throughput and form an optimal MU-MIMO transmission.
