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
In this paper, the performance of a 60 GHz radio over fiber(Ro F) system with 4/16/64 quadrature amplitude modulation(QAM) orthogonal frequency division multiplexing(OFDM) downstream signals is studied. Delivery of 10...In this paper, the performance of a 60 GHz radio over fiber(Ro F) system with 4/16/64 quadrature amplitude modulation(QAM) orthogonal frequency division multiplexing(OFDM) downstream signals is studied. Delivery of 10 Gbit/s M-ary QAM(MQAM) OFDM signals through the 20-km-long single-mode fiber(SMF) is complicated in terms of intensity modulation and direct detection(IM/DD). Using self-homodyne method, the beating of two independent light waves generating the millimeter-wave at the photodetector can be down-converted to baseband in the electrical domain. Meanwhile, three kinds of sub-carrier arrangement schemes are compared and discussed, and the simulation results show that lower peak-to-average power ratio(PAPR) can be obtained adopting the adjacent scheme. At bit error rate(BER) of 10^(-3), the receiver sensitivity using 4QAM-OFDM sub-carrier signal is almost enhanced by 4 dB and 9 dB compared with those of 16 QAM-OFDM signal and 64 QAM-OFDM signal.展开更多
为了提高卫星通信的频谱利用效率,提出基于认知无线电的非连续正交频分复用(Non-continuous Orthogonal Frequency Division Multiplexing,NC-OFDM)卫星通信方法,研究了NC-OFDM子载波分配方法、系统建模仿真和对授权用户的干扰分析。基...为了提高卫星通信的频谱利用效率,提出基于认知无线电的非连续正交频分复用(Non-continuous Orthogonal Frequency Division Multiplexing,NC-OFDM)卫星通信方法,研究了NC-OFDM子载波分配方法、系统建模仿真和对授权用户的干扰分析。基于频谱感知的子载波分配方法实现了NC-OFDM卫星通信系统对频谱空洞的有效利用,系统仿真结果和干扰分析表明,NC-OFDM卫星通信能够提高频谱利用率,并且在采用频谱感知和自适应信道接入技术的条件下,NC-OFDM卫星通信系统能够与授权用户实现频谱兼容。展开更多
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.
基金supported by the National Natural Science Foundation of China(No.61107064)the Bayu Scholars Founding,the Chongqing University Innovation Team Founding(No.KJTD201320)+3 种基金the Chongqing Science and Technology Commission Foundation(Nos.cstc2014jcyj A40046,cstc2016jcyj A1233 and cstc2016jcyj A0246)the Chongqing 2011 Collaborative Innovation Center Project(Chongqing Education Department(2016)No.40)the Chongqing Graduate Scientific Research Innovation Project(Nos.CYS15225 and CYS16225)the Science and Technology Special Funds in Wanzhou District
文摘In this paper, the performance of a 60 GHz radio over fiber(Ro F) system with 4/16/64 quadrature amplitude modulation(QAM) orthogonal frequency division multiplexing(OFDM) downstream signals is studied. Delivery of 10 Gbit/s M-ary QAM(MQAM) OFDM signals through the 20-km-long single-mode fiber(SMF) is complicated in terms of intensity modulation and direct detection(IM/DD). Using self-homodyne method, the beating of two independent light waves generating the millimeter-wave at the photodetector can be down-converted to baseband in the electrical domain. Meanwhile, three kinds of sub-carrier arrangement schemes are compared and discussed, and the simulation results show that lower peak-to-average power ratio(PAPR) can be obtained adopting the adjacent scheme. At bit error rate(BER) of 10^(-3), the receiver sensitivity using 4QAM-OFDM sub-carrier signal is almost enhanced by 4 dB and 9 dB compared with those of 16 QAM-OFDM signal and 64 QAM-OFDM signal.
文摘为了提高卫星通信的频谱利用效率,提出基于认知无线电的非连续正交频分复用(Non-continuous Orthogonal Frequency Division Multiplexing,NC-OFDM)卫星通信方法,研究了NC-OFDM子载波分配方法、系统建模仿真和对授权用户的干扰分析。基于频谱感知的子载波分配方法实现了NC-OFDM卫星通信系统对频谱空洞的有效利用,系统仿真结果和干扰分析表明,NC-OFDM卫星通信能够提高频谱利用率,并且在采用频谱感知和自适应信道接入技术的条件下,NC-OFDM卫星通信系统能够与授权用户实现频谱兼容。
