MIMO和OFDM是B3G和4G宽带无线通信的关键技术之一,能极大地提高信道的频谱利用率。传统的通信系统的设计都采用Matlab仿真,该文采用SystemC对4×4 MIMO OFDM无线通信系统进行了仿真实现。研究结果表明:MIMO OFDM系统能获得更高的数...MIMO和OFDM是B3G和4G宽带无线通信的关键技术之一,能极大地提高信道的频谱利用率。传统的通信系统的设计都采用Matlab仿真,该文采用SystemC对4×4 MIMO OFDM无线通信系统进行了仿真实现。研究结果表明:MIMO OFDM系统能获得更高的数据率和更好的传输质量,使用SystemC仿真速度快,易于硬件实现,而且更节约系统资源。展开更多
A new type hybrid automatic repeat request(HARQ) scheme based on orthogonal space-time block code(OSTBC) is proposed and evaluated in multiple-input multiple-output(MIMO) systems.The transmit antennas are selected bas...A new type hybrid automatic repeat request(HARQ) scheme based on orthogonal space-time block code(OSTBC) is proposed and evaluated in multiple-input multiple-output(MIMO) systems.The transmit antennas are selected based on the feedback from the receiver.The modulated symbols are encoded by spacetime block code(STBC) and obtained by space time code blocks which are suitable for the number of selected antennas.The total packet error rate(PER) is given by defining the decoding function and the best value of the maximum number of HARQ retransmissions is discussed.Theory and simulation results illustrate that:this new HARQ scheme with antenna selection method has lower PER and the result is also satisfying.展开更多
An appropriate coding method that can reduce the error rate of communication system is especially important to the free space optical communication. STBC （space-time block code） is an orthogonal encoding method inte...An appropriate coding method that can reduce the error rate of communication system is especially important to the free space optical communication. STBC （space-time block code） is an orthogonal encoding method integrating space domain and time domain. The technology can combat fading effectively and improve error rate performance. In this paper, first, an STBC fit for optical communication with intensity modulation and direct detection （IM/DD） is proposed by combining the orthogonality of the Alamouti space-time code and the QPPM modulation. Then, the error rate performance of the system is analyzed under four cases： with or without channel fading, with or without background radiation. At last, this scheme is confirmed by Monte Carlo approach. It is shown that this method not only realizes the full speed rate transmission, and can improve the error rate performance of the system effectively, but also overcomes the scintillation effect exerted by atmosphere turbulence. When the symbol error probability （SEP） is 2×10^-3, according to the 1× 1 system, the sending power of the 2×1 system is nearly reduced by 3.5 dBJ, and the 2×2 system is nearly reduced by 9 dBJ.展开更多
Performance analysis is presented for multiple-input multiple-output （MIMO） relay channels employing transmit antenna diversity with orthogonal space-time block codes （OSTBCs）, where the source and the destination...Performance analysis is presented for multiple-input multiple-output （MIMO） relay channels employing transmit antenna diversity with orthogonal space-time block codes （OSTBCs）, where the source and the destination are equipped with Ns and Nd antennas, and communicate with each other with the help of a multiple-antenna relay operating in decode-and-forward （DF） mode Over independent, not necessarily identical Rayleigh fading channels, exact closed-form symbol error rate （SER） expressions are derived for various digital modulation formats for both the OSTBC transmission with and without the direct link, The moment generating functions （MGFs） for overall system signal-noise ratios （SNRs） are also derived, based on which we present a unified SER analysis. The analysis shows that full spatial diversity order can be achieved for the DF M1MO relay channel by adopting OSTBC transmissions and maximal ratio combining （MRC） receptions. All the analytical results are confirmed through comparison with the results obtained using Mento Carlo simulations.展开更多
文摘MIMO和OFDM是B3G和4G宽带无线通信的关键技术之一,能极大地提高信道的频谱利用率。传统的通信系统的设计都采用Matlab仿真,该文采用SystemC对4×4 MIMO OFDM无线通信系统进行了仿真实现。研究结果表明:MIMO OFDM系统能获得更高的数据率和更好的传输质量,使用SystemC仿真速度快,易于硬件实现,而且更节约系统资源。
文摘A new type hybrid automatic repeat request(HARQ) scheme based on orthogonal space-time block code(OSTBC) is proposed and evaluated in multiple-input multiple-output(MIMO) systems.The transmit antennas are selected based on the feedback from the receiver.The modulated symbols are encoded by spacetime block code(STBC) and obtained by space time code blocks which are suitable for the number of selected antennas.The total packet error rate(PER) is given by defining the decoding function and the best value of the maximum number of HARQ retransmissions is discussed.Theory and simulation results illustrate that:this new HARQ scheme with antenna selection method has lower PER and the result is also satisfying.
基金Supported by the Defence Major Laboratory Fund (Grant No. 9140C3601010701)the Science Special Fund of the Education Department of Shaanxi Province (Grant No. 07JK332)+2 种基金the Natural Science Fund of Shaanxi Province (Grant No. 2007F12)the Science and Technology Project of the Communications of Guangdong Province (Grant No. 2007-26)and the Fund of Excellent Doctor Degree of Xi’an University of 9 Technology (Grant No. 602-210808)
文摘An appropriate coding method that can reduce the error rate of communication system is especially important to the free space optical communication. STBC （space-time block code） is an orthogonal encoding method integrating space domain and time domain. The technology can combat fading effectively and improve error rate performance. In this paper, first, an STBC fit for optical communication with intensity modulation and direct detection （IM/DD） is proposed by combining the orthogonality of the Alamouti space-time code and the QPPM modulation. Then, the error rate performance of the system is analyzed under four cases： with or without channel fading, with or without background radiation. At last, this scheme is confirmed by Monte Carlo approach. It is shown that this method not only realizes the full speed rate transmission, and can improve the error rate performance of the system effectively, but also overcomes the scintillation effect exerted by atmosphere turbulence. When the symbol error probability （SEP） is 2×10^-3, according to the 1× 1 system, the sending power of the 2×1 system is nearly reduced by 3.5 dBJ, and the 2×2 system is nearly reduced by 9 dBJ.
基金supported by the National Basic Research Program of China (2007CB310602)the BUPT Excellent Ph.D. Students Foundation (CX200903)
文摘Performance analysis is presented for multiple-input multiple-output （MIMO） relay channels employing transmit antenna diversity with orthogonal space-time block codes （OSTBCs）, where the source and the destination are equipped with Ns and Nd antennas, and communicate with each other with the help of a multiple-antenna relay operating in decode-and-forward （DF） mode Over independent, not necessarily identical Rayleigh fading channels, exact closed-form symbol error rate （SER） expressions are derived for various digital modulation formats for both the OSTBC transmission with and without the direct link, The moment generating functions （MGFs） for overall system signal-noise ratios （SNRs） are also derived, based on which we present a unified SER analysis. The analysis shows that full spatial diversity order can be achieved for the DF M1MO relay channel by adopting OSTBC transmissions and maximal ratio combining （MRC） receptions. All the analytical results are confirmed through comparison with the results obtained using Mento Carlo simulations.
