This paper considers an intelligent reflecting surface(IRS)-assisted multiple-input multiple-output(MIMO)system.To maximize the average achievable rate(AAR)under outdated channel state information(CSI),we propose a tw...This paper considers an intelligent reflecting surface(IRS)-assisted multiple-input multiple-output(MIMO)system.To maximize the average achievable rate(AAR)under outdated channel state information(CSI),we propose a twin-timescale passive beamforming(PBF)and power allocation protocol which can reduce the IRS configuration and training overhead.Specifi-cally,the short-timescale power allocation is designed with the outdated precoder and fixed PBF.A new particle swarm opti-mization(PSO)-based long-timescale PBF optimization is pro-posed,where mini-batch channel samples are utilized to update the fitness function.Finally,simulation results demonstrate the effectiveness of the proposed method.展开更多
This article examines Gatsby's dream to point out some positive aspects of Gatsby and the causes leading to his tragedy so as to see whether it is outdated or avant-garde as well as to reflect on the present society.
The impact of outdated Channel State Information(CSI) on the performance of relay selections,including the partial relay selection and the best relay selection,is studied,with respect to Amplify-and-Forward(AF) mode c...The impact of outdated Channel State Information(CSI) on the performance of relay selections,including the partial relay selection and the best relay selection,is studied,with respect to Amplify-and-Forward(AF) mode cooperative systems.The proposed method is analysed by deriving the asymptotic closedform expressions for some figures of merit such as the outage probability and the Symbol Error Probability(SEP).Moreover,the validity of the proposed theoretical analysis is proven via simulations.Numerical results prove that the performance of the proposed scheme is impacted considerably by various parameters such as the number of candidate relays and the end-to-end Signal-to-Noise Ratio(SNR).In the presence of cooperative networks with outdated CSI feedback,a performance improvement of more than 3 dB in terms of either outage probability or SEP can be observed by utilizing the Source-to-Destination(S D) link rather than the method of simply increasing the number of relays.展开更多
This paper investigates the effects of the outdated channel state information(CSI)on the secrecy performance of an underlay spectrum sharing cognitive radio networks(CRNs),where the secondary user(SU)source node(Alice...This paper investigates the effects of the outdated channel state information(CSI)on the secrecy performance of an underlay spectrum sharing cognitive radio networks(CRNs),where the secondary user(SU)source node(Alice)aims to transmit the trusted messages to the full-duplex(FD)aided SU receiver(Bob)with the assistance of cooperative relay(Relay).Considering the impact of feedback delay,outdated CSI will aggravate the system performance.To tackle such challenge,the collaborative zero-forcing beamforming(ZFB)scheme of FD technique is further introduced to implement jamming so as to confuse the eavesdropping and improve the security performance of the system.Under such setup,the exact and asymptotic expressions of the secrecy outage probability(SOP)under the outdated CSI case are derived,respectively.The results reveal that i)the outdated CSI of the SU transmission channel will decrease the diversity gain from min(NANR,NRNB)to NRwith NA,NRand NBbeing the number of antennas of Alice,Relay and Bob,respectively,ii)the introduction of FD technique can improve coding gain and enhance system performance.展开更多
In this paper, we consider an amplify-and-forward (AF) cooperative communication system when the channel state information (CSI) used in relay selection differs from that during data transmission, i.e., the CSI us...In this paper, we consider an amplify-and-forward (AF) cooperative communication system when the channel state information (CSI) used in relay selection differs from that during data transmission, i.e., the CSI used in relay selection is outdated. The selected relay may not be actually the best for data transmission and the outage performance of the cooperative system will deteriorate. To improve its performance, we propose a relay selection strategy based on maximum a posteriori (MAP) estimation, where relay is selected based on predicted signal-to-noise ratio (SNR). To reduce the computation complexity, we approximate the a posteriori probability density of SNR and obtain a closed-form predicted SNR, and a relay selection strategy based on the approximate MAP estimation (RS-AMAP) is proposed. The simulation results show that this approximation leads to trivial performance loss from the perspective of outage probability. Compared with relay selection strategies given in the literature, the outage probability is reduced largely through RS-AMAP for medium-to-large transmitting powers and medium-to-high channel correlation coefficients.展开更多
According to the consideration of the advantage of drilling,it is usually a kind of prac-tice that helps students to acquire fluency in the language by training them to produce lan-guage patterns automatically and wit...According to the consideration of the advantage of drilling,it is usually a kind of prac-tice that helps students to acquire fluency in the language by training them to produce lan-guage patterns automatically and without conscious effort.But in recent years,there is agreat and heated arguement about drilling activities.展开更多
Food insecurity continues to plague many rural communities across Africa.In Ghana and many neighbouring countries,smallholder farmers still struggle to make ends meet due to poor yields,outdated practices,and minimal ...Food insecurity continues to plague many rural communities across Africa.In Ghana and many neighbouring countries,smallholder farmers still struggle to make ends meet due to poor yields,outdated practices,and minimal institutional support.They face a plethora of challenges,including limited access to technology,weak extension systems,and a gap between scientific knowledge and everyday farming.展开更多
“Transformation is not simply about shutting down;it is more about eliminating outdated production capacity while nurturing new driving forces,”according to Wan Qian,a member of the Standing Committee of the Xiangxi...“Transformation is not simply about shutting down;it is more about eliminating outdated production capacity while nurturing new driving forces,”according to Wan Qian,a member of the Standing Committee of the Xiangxiang Municipal Party Committee,referring to an eco-friendly chemical industrial park in Xiangxiang City,central China’s Hunan Province.展开更多
The cross-layer resource allocation problem in wireless multi-hop networks(WMHNs)has been extensively studied in the past few years.Most of these studies assume that every node has the perfect channel state informatio...The cross-layer resource allocation problem in wireless multi-hop networks(WMHNs)has been extensively studied in the past few years.Most of these studies assume that every node has the perfect channel state information(CSI)of other nodes.In practical settings,however,the networks are generally dynamic and CSI usually becomes outdated when it is used,due to the time-variant channel and feedback delay.To deal with this issue,we study the cross-layer resource allocation problem in dynamic WMHNs with outdated CSI under channel conditions where there is correlation between the outdated CSI and current CSI.Two major contributions are made in this work:(1)a closed-form expression of conditional average capacity is derived under the signal-to-interferenceplus-noise ratio(SINR)model;(2)a joint optimization problem of congestion control,power control,and channel allocation in the context of outdated CSI is formulated and solved in both centralized and distributed manners.Simulation results show that the network utility can be improved significantly using our proposed algorithm.展开更多
It's a subject that gets not only animal rights activists hot under the collar, but also the vast majority of caring people concerned about cruelty to animals. At a press conference in early 2006, the world's ...It's a subject that gets not only animal rights activists hot under the collar, but also the vast majority of caring people concerned about cruelty to animals. At a press conference in early 2006, the world's attention was once again drawn to the fate of Asiatic black bears (or moon bears) in China, so long tortured in the cruel practice of bile extraction. Only this展开更多
Integrated data and energy transfer(IDET)is capable of simultaneously delivering on-demand data and energy to low-power Internet of Everything(Io E)devices.We propose a multi-carrier IDET transceiver relying on superp...Integrated data and energy transfer(IDET)is capable of simultaneously delivering on-demand data and energy to low-power Internet of Everything(Io E)devices.We propose a multi-carrier IDET transceiver relying on superposition waveforms consisting of multi-sinusoidal signals for wireless energy transfer(WET)and orthogonal-frequency-divisionmultiplexing(OFDM)signals for wireless data transfer(WDT).The outdated channel state information(CSI)in aging channels is employed by the transmitter to shape IDET waveforms.With the constraints of transmission power and WDT requirement,the amplitudes and phases of the IDET waveform at the transmitter and the power splitter at the receiver are jointly optimised for maximising the average directcurrent(DC)among a limited number of transmission frames with the existence of carrier-frequencyoffset(CFO).For the amplitude optimisation,the original non-convex problem can be transformed into a reversed geometric programming problem,then it can be effectively solved with existing tools.As for the phase optimisation,the artificial bee colony(ABC)algorithm is invoked in order to deal with the nonconvexity.Iteration between the amplitude optimisation and phase optimisation yields our joint design.Numerical results demonstrate the advantage of our joint design for the IDET waveform shaping with the existence of the CFO and the outdated CSI.展开更多
Due to the proliferation of mobile internet access, the cellu-lar traffic is envisaged to experience a 1000-fold growth inthe second decade of the 21 st century. To meet such a hugetraffic demand, the Fifth Generation...Due to the proliferation of mobile internet access, the cellu-lar traffic is envisaged to experience a 1000-fold growth inthe second decade of the 21 st century. To meet such a hugetraffic demand, the Fifth Generation(5G) network have toadopt new techniques to substantially increase spectral effi-ciency and reliability. At the base station side, available re-sources(power supply, equipment size, processing capability,etc.) are far more sufficient than that of the terminal side,which imposes a high challenge on the uplink transmission.The concept of cooperative communications opens a possibili-ty of using multiple terminals to cooperatively achieve spa-tial diversity that is typically obtained by means of multipleantennas in the base station. The application of Device-to-Device(D2D) communications in the 3GPP LTE system fur-ther pushes the collaboration of terminals from the theory tothe practice. The utilization of D2D-based cooperative relay-ing is promising in the era of 5G. In this paper, we compara-tively study several cooperative multi-relay schemes, includ-ing the proposed opportunistic space-time coding, in thepresence of imperfect channel state information. The numeri-cal results reveal that the proposed scheme is the best coop-erative solution until now from the perspective of multiplex-ing-diversity tradeoff.展开更多
RSS fingerprint based indoor localization consists of two phases:offline phase and online phase.A RSS fingerprint database constructed at the offline phase may be outdated for online phase,which may significantly degr...RSS fingerprint based indoor localization consists of two phases:offline phase and online phase.A RSS fingerprint database constructed at the offline phase may be outdated for online phase,which may significantly degrade the localization performance.Furthermore,maintaining an RSS fingerprint database is a labor intensive and time-consuming task.In this paper,we proposes a robust and iterative indoor localization algorithm based on Wi-Fi RSS fingerprints,referred to as RIFi,which does not need to update the RSS fingerprint database and perform well even if the RSS fingerprint database is outdated.Specifically,we demonstrate that smaller localization area can provides better performance for outdated fingerprint database.Furthermore,we propose an iterative algorithm to determine the smaller localization area.Finally,the K-nearest neighbors(KNN)algorithm is invoked for the determined smaller localization area.Simulation results show that the proposed RIFi algorithm can significantly outperforms the traditional KNN algorithm for outdated RSS fingerprint database,and is more robust.展开更多
As the main power source of China, coalfired power industry has achieved a great progress in installed capacity, manufacturing technologies, thermal efficiency, as well as pollutant control during the past century. Wi...As the main power source of China, coalfired power industry has achieved a great progress in installed capacity, manufacturing technologies, thermal efficiency, as well as pollutant control during the past century. With the fast development of renewable energies, coal-fired power industry is experiencing a strategic transformation. To specify the development of coal-fired power industry, its development history is reviewed and the technical progresses on aspects of thermal efficiency, pollutants control and peaking shaving capacity are discussed. It is concluded that the role of China's coal-fired power source would be transformed from the dominant position to a base position in power source structure. Considering the sustainable development of coal-fired power industry in energy conservation, emission control, and utilization of renewable energies, it is suggested that the national average thermal efficiency should be improved by continual up-gradation of units by using advanced technologies and eliminating outdated capacity. Moreover, the emission standard of air pollutants should not be stricter any more in coal-fired power industry. Furthermore, the huge amount of combined heat and power (CHP) coal-fired units should be operated in a decoupled way, so as to release more than 350 GW regulation capacity for the grid to accept more renewable energy power.展开更多
The performance of multiuser multiple-input-multiple-output (MIMO) downlink systems with block diagonalization (BD) depends on the accuracy of the channel state information (CSI) available at the trans- mitter a...The performance of multiuser multiple-input-multiple-output (MIMO) downlink systems with block diagonalization (BD) depends on the accuracy of the channel state information (CSI) available at the trans- mitter and the receiver. In time-varying channels, the CSI available at the transmitter (CSIT) is always out-dated due to an inherent time delay between the uplink channel estimation and the downlink data transmission in time division duplexing (TDD) systems. This leads to a drastic degradation of system capacity. This paper first analyzes the effect of the outdated CSIT on multiuser MIMO downlink systems using the BD method and then proposes two linear processing methods, BD precoding with user selection and scheduling at the transmitter and total minimum mean squared error (MMSE) decoding at the receiver (TBDUSS-RTMMSE) and BD preceding at the transmitter with partial MMSE decoding at the receiver (TBD-RPMMSE), to mitigate the interference among data streams and users. Analysis and simulation results show that these methods can effectively reduce the impairment of the outdated CSIT to increase the system sum capacity in a suitable time delay region of the CSIT.展开更多
基金supported by the National Natural Science Foundation of China(62271068)the Beijing Natural Science Foundation(L222046).
文摘This paper considers an intelligent reflecting surface(IRS)-assisted multiple-input multiple-output(MIMO)system.To maximize the average achievable rate(AAR)under outdated channel state information(CSI),we propose a twin-timescale passive beamforming(PBF)and power allocation protocol which can reduce the IRS configuration and training overhead.Specifi-cally,the short-timescale power allocation is designed with the outdated precoder and fixed PBF.A new particle swarm opti-mization(PSO)-based long-timescale PBF optimization is pro-posed,where mini-batch channel samples are utilized to update the fitness function.Finally,simulation results demonstrate the effectiveness of the proposed method.
文摘This article examines Gatsby's dream to point out some positive aspects of Gatsby and the causes leading to his tragedy so as to see whether it is outdated or avant-garde as well as to reflect on the present society.
基金supported by the National Key Basic Research Program of China (973 Program) under Grant No. 2012CB315905the National Natural Science Foundation of China under Grants No. 61172050,No. 60903211+3 种基金the Foundation of Beijing Engineering and Technology Centre for Convergence Networks and Ubiquitous Servicesthe National Key Projects under Grants No. 2012ZX03001029-005,No. 2012ZX03001032-003Beijing Science and Technology Program under Grant No. Z1111-00054011078Program for New Century Excellent Talents in University under GrantNo. NCET-12-0774
文摘The impact of outdated Channel State Information(CSI) on the performance of relay selections,including the partial relay selection and the best relay selection,is studied,with respect to Amplify-and-Forward(AF) mode cooperative systems.The proposed method is analysed by deriving the asymptotic closedform expressions for some figures of merit such as the outage probability and the Symbol Error Probability(SEP).Moreover,the validity of the proposed theoretical analysis is proven via simulations.Numerical results prove that the performance of the proposed scheme is impacted considerably by various parameters such as the number of candidate relays and the end-to-end Signal-to-Noise Ratio(SNR).In the presence of cooperative networks with outdated CSI feedback,a performance improvement of more than 3 dB in terms of either outage probability or SEP can be observed by utilizing the Source-to-Destination(S D) link rather than the method of simply increasing the number of relays.
基金supported by the National Natural Science Foundation of China(No.62201606 and No.62071486)the Project of Science and Technology Planning of Guizhou Province(No.[2020]-030)+3 种基金the Project of Science and Technology Fund of Guizhou Provincial Health Commission(gzwkj2022524)the Project of Youth Science and Technology Talent Growth Guizhou Provincial Department of Education(No.KY[2021]230)the Key Research Base Project of Humanities and Social Sciences of Education Department of Guizhou Provincethe Project of Science and Technology Planning of Zunyi City(No.2022-381 and No.2022-384)。
文摘This paper investigates the effects of the outdated channel state information(CSI)on the secrecy performance of an underlay spectrum sharing cognitive radio networks(CRNs),where the secondary user(SU)source node(Alice)aims to transmit the trusted messages to the full-duplex(FD)aided SU receiver(Bob)with the assistance of cooperative relay(Relay).Considering the impact of feedback delay,outdated CSI will aggravate the system performance.To tackle such challenge,the collaborative zero-forcing beamforming(ZFB)scheme of FD technique is further introduced to implement jamming so as to confuse the eavesdropping and improve the security performance of the system.Under such setup,the exact and asymptotic expressions of the secrecy outage probability(SOP)under the outdated CSI case are derived,respectively.The results reveal that i)the outdated CSI of the SU transmission channel will decrease the diversity gain from min(NANR,NRNB)to NRwith NA,NRand NBbeing the number of antennas of Alice,Relay and Bob,respectively,ii)the introduction of FD technique can improve coding gain and enhance system performance.
基金National Basic Research Program of China(No.2010CB731803)
文摘In this paper, we consider an amplify-and-forward (AF) cooperative communication system when the channel state information (CSI) used in relay selection differs from that during data transmission, i.e., the CSI used in relay selection is outdated. The selected relay may not be actually the best for data transmission and the outage performance of the cooperative system will deteriorate. To improve its performance, we propose a relay selection strategy based on maximum a posteriori (MAP) estimation, where relay is selected based on predicted signal-to-noise ratio (SNR). To reduce the computation complexity, we approximate the a posteriori probability density of SNR and obtain a closed-form predicted SNR, and a relay selection strategy based on the approximate MAP estimation (RS-AMAP) is proposed. The simulation results show that this approximation leads to trivial performance loss from the perspective of outage probability. Compared with relay selection strategies given in the literature, the outage probability is reduced largely through RS-AMAP for medium-to-large transmitting powers and medium-to-high channel correlation coefficients.
文摘According to the consideration of the advantage of drilling,it is usually a kind of prac-tice that helps students to acquire fluency in the language by training them to produce lan-guage patterns automatically and without conscious effort.But in recent years,there is agreat and heated arguement about drilling activities.
文摘Food insecurity continues to plague many rural communities across Africa.In Ghana and many neighbouring countries,smallholder farmers still struggle to make ends meet due to poor yields,outdated practices,and minimal institutional support.They face a plethora of challenges,including limited access to technology,weak extension systems,and a gap between scientific knowledge and everyday farming.
文摘“Transformation is not simply about shutting down;it is more about eliminating outdated production capacity while nurturing new driving forces,”according to Wan Qian,a member of the Standing Committee of the Xiangxiang Municipal Party Committee,referring to an eco-friendly chemical industrial park in Xiangxiang City,central China’s Hunan Province.
基金supported by the National Natural Science Foundation of China(No.61340035)
文摘The cross-layer resource allocation problem in wireless multi-hop networks(WMHNs)has been extensively studied in the past few years.Most of these studies assume that every node has the perfect channel state information(CSI)of other nodes.In practical settings,however,the networks are generally dynamic and CSI usually becomes outdated when it is used,due to the time-variant channel and feedback delay.To deal with this issue,we study the cross-layer resource allocation problem in dynamic WMHNs with outdated CSI under channel conditions where there is correlation between the outdated CSI and current CSI.Two major contributions are made in this work:(1)a closed-form expression of conditional average capacity is derived under the signal-to-interferenceplus-noise ratio(SINR)model;(2)a joint optimization problem of congestion control,power control,and channel allocation in the context of outdated CSI is formulated and solved in both centralized and distributed manners.Simulation results show that the network utility can be improved significantly using our proposed algorithm.
文摘It's a subject that gets not only animal rights activists hot under the collar, but also the vast majority of caring people concerned about cruelty to animals. At a press conference in early 2006, the world's attention was once again drawn to the fate of Asiatic black bears (or moon bears) in China, so long tortured in the cruel practice of bile extraction. Only this
基金financial support of Natural Science Foundation of China(No.61971102,62132004)MOST Major Research and Development Project(No.2021YFB2900204)+1 种基金Sichuan Science and Technology Program(No.2022YFH0022)Key Research and Development Program of Zhejiang Province(No.2022C01093)。
文摘Integrated data and energy transfer(IDET)is capable of simultaneously delivering on-demand data and energy to low-power Internet of Everything(Io E)devices.We propose a multi-carrier IDET transceiver relying on superposition waveforms consisting of multi-sinusoidal signals for wireless energy transfer(WET)and orthogonal-frequency-divisionmultiplexing(OFDM)signals for wireless data transfer(WDT).The outdated channel state information(CSI)in aging channels is employed by the transmitter to shape IDET waveforms.With the constraints of transmission power and WDT requirement,the amplitudes and phases of the IDET waveform at the transmitter and the power splitter at the receiver are jointly optimised for maximising the average directcurrent(DC)among a limited number of transmission frames with the existence of carrier-frequencyoffset(CFO).For the amplitude optimisation,the original non-convex problem can be transformed into a reversed geometric programming problem,then it can be effectively solved with existing tools.As for the phase optimisation,the artificial bee colony(ABC)algorithm is invoked in order to deal with the nonconvexity.Iteration between the amplitude optimisation and phase optimisation yields our joint design.Numerical results demonstrate the advantage of our joint design for the IDET waveform shaping with the existence of the CFO and the outdated CSI.
文摘Due to the proliferation of mobile internet access, the cellu-lar traffic is envisaged to experience a 1000-fold growth inthe second decade of the 21 st century. To meet such a hugetraffic demand, the Fifth Generation(5G) network have toadopt new techniques to substantially increase spectral effi-ciency and reliability. At the base station side, available re-sources(power supply, equipment size, processing capability,etc.) are far more sufficient than that of the terminal side,which imposes a high challenge on the uplink transmission.The concept of cooperative communications opens a possibili-ty of using multiple terminals to cooperatively achieve spa-tial diversity that is typically obtained by means of multipleantennas in the base station. The application of Device-to-Device(D2D) communications in the 3GPP LTE system fur-ther pushes the collaboration of terminals from the theory tothe practice. The utilization of D2D-based cooperative relay-ing is promising in the era of 5G. In this paper, we compara-tively study several cooperative multi-relay schemes, includ-ing the proposed opportunistic space-time coding, in thepresence of imperfect channel state information. The numeri-cal results reveal that the proposed scheme is the best coop-erative solution until now from the perspective of multiplex-ing-diversity tradeoff.
基金supported by the Key Research and Development Program of Shaanxi under Grant(2017DCXL-GY-04-02).
文摘RSS fingerprint based indoor localization consists of two phases:offline phase and online phase.A RSS fingerprint database constructed at the offline phase may be outdated for online phase,which may significantly degrade the localization performance.Furthermore,maintaining an RSS fingerprint database is a labor intensive and time-consuming task.In this paper,we proposes a robust and iterative indoor localization algorithm based on Wi-Fi RSS fingerprints,referred to as RIFi,which does not need to update the RSS fingerprint database and perform well even if the RSS fingerprint database is outdated.Specifically,we demonstrate that smaller localization area can provides better performance for outdated fingerprint database.Furthermore,we propose an iterative algorithm to determine the smaller localization area.Finally,the K-nearest neighbors(KNN)algorithm is invoked for the determined smaller localization area.Simulation results show that the proposed RIFi algorithm can significantly outperforms the traditional KNN algorithm for outdated RSS fingerprint database,and is more robust.
基金This work was supported by China Postdoctoral Science Foundation (2017M620758)Special Funds of the National Natural Science Foundation of China (Grant No. LI522032)the Consulting Project of Chinese Academy of Engineering (No. 2015-ZCQ-06).
文摘As the main power source of China, coalfired power industry has achieved a great progress in installed capacity, manufacturing technologies, thermal efficiency, as well as pollutant control during the past century. With the fast development of renewable energies, coal-fired power industry is experiencing a strategic transformation. To specify the development of coal-fired power industry, its development history is reviewed and the technical progresses on aspects of thermal efficiency, pollutants control and peaking shaving capacity are discussed. It is concluded that the role of China's coal-fired power source would be transformed from the dominant position to a base position in power source structure. Considering the sustainable development of coal-fired power industry in energy conservation, emission control, and utilization of renewable energies, it is suggested that the national average thermal efficiency should be improved by continual up-gradation of units by using advanced technologies and eliminating outdated capacity. Moreover, the emission standard of air pollutants should not be stricter any more in coal-fired power industry. Furthermore, the huge amount of combined heat and power (CHP) coal-fired units should be operated in a decoupled way, so as to release more than 350 GW regulation capacity for the grid to accept more renewable energy power.
基金Supported by the National High-Tech Research and Development (863) Program of China (No. 2006AA01Z282)the Tsinghua-Qualcomm Project
文摘The performance of multiuser multiple-input-multiple-output (MIMO) downlink systems with block diagonalization (BD) depends on the accuracy of the channel state information (CSI) available at the trans- mitter and the receiver. In time-varying channels, the CSI available at the transmitter (CSIT) is always out-dated due to an inherent time delay between the uplink channel estimation and the downlink data transmission in time division duplexing (TDD) systems. This leads to a drastic degradation of system capacity. This paper first analyzes the effect of the outdated CSIT on multiuser MIMO downlink systems using the BD method and then proposes two linear processing methods, BD precoding with user selection and scheduling at the transmitter and total minimum mean squared error (MMSE) decoding at the receiver (TBDUSS-RTMMSE) and BD preceding at the transmitter with partial MMSE decoding at the receiver (TBD-RPMMSE), to mitigate the interference among data streams and users. Analysis and simulation results show that these methods can effectively reduce the impairment of the outdated CSIT to increase the system sum capacity in a suitable time delay region of the CSIT.