发射分集是克服信道衰落的有效方式,而LAS CDMA由于特有的智慧编 码技术而具有优异的特性。对三种发射分集方式(OTD,STTD,STS)与LAS CD MA结合的性能进行了研究,从理论上推导了采用这几种方式后的信干比表达式,并 且在L...发射分集是克服信道衰落的有效方式,而LAS CDMA由于特有的智慧编 码技术而具有优异的特性。对三种发射分集方式(OTD,STTD,STS)与LAS CD MA结合的性能进行了研究,从理论上推导了采用这几种方式后的信干比表达式,并 且在LAS CDMA中仿真了其性能,并与传统CDMA进行了比较。表明发射分集与 LAS CDMA相结合能充分的发挥两者的优越特性。展开更多
为了提高在衰落信道下数字电视地面广播系统的传输性能,在时域同步正交频分复用(TDS-OFDM)系统中应用空时、空频两种发射分集方法。根据系统信号帧结构的特点,提出了简单易行的发射链路信号配置方法,保持原有链路不变,运算复杂度小。同...为了提高在衰落信道下数字电视地面广播系统的传输性能,在时域同步正交频分复用(TDS-OFDM)系统中应用空时、空频两种发射分集方法。根据系统信号帧结构的特点,提出了简单易行的发射链路信号配置方法,保持原有链路不变,运算复杂度小。同时,分析了空时、空频两种分集方法的适用范围。仿真结果表明:在慢衰落信道下,两种方法都能提高系统的误码性能,当误码率为10-3时有不低于8dB的分集增益;在快衰落信道下,空时分集性能受D opp ler频移的影响而变得很差,空频分集的增益则与在慢衰落信道时相近。对于不同类型的信道采用合适的发射分集方法,数字电视地面广播系统的传输性能可以得到很大提高。展开更多
Space time coding can provide high data rate and performance gain for wireless communication system. Performance comparison of space time trellis codes and space time transmit diversity is carried out under the sam...Space time coding can provide high data rate and performance gain for wireless communication system. Performance comparison of space time trellis codes and space time transmit diversity is carried out under the same bandwidth efficiency in this paper. We also propose some optimum low rate space time trellis codes in quasi static Rayleigh fading chan￣nel. Performance analysis and simulation show that the low rate space time trellis codes outperform space time transmit diversity at the same bandwidth efficiency, and are more suitable for the power limited wireless communication system which has no strict requirement on bandwidth efficiency.展开更多
Space-time spreading (STS) and orthogonal transmit diversity (OTD) are towtransmit diversity schemes proposed by cdma2000 standard. In this paper, performance comparisonanalysis of the two transmits diversity schemes ...Space-time spreading (STS) and orthogonal transmit diversity (OTD) are towtransmit diversity schemes proposed by cdma2000 standard. In this paper, performance comparisonanalysis of the two transmits diversity schemes in multipath channel under multiuser situation arecarried out. Link level simulation in forward link cdma2000 is performed in IMT-2000 channel.Performance analysis and simulation results show that the performance improvement provided STS overOTD decreases as the increase of propagation path number and decrease of the user number.展开更多
文摘发射分集是克服信道衰落的有效方式,而LAS CDMA由于特有的智慧编 码技术而具有优异的特性。对三种发射分集方式(OTD,STTD,STS)与LAS CD MA结合的性能进行了研究,从理论上推导了采用这几种方式后的信干比表达式,并 且在LAS CDMA中仿真了其性能,并与传统CDMA进行了比较。表明发射分集与 LAS CDMA相结合能充分的发挥两者的优越特性。
文摘为了提高在衰落信道下数字电视地面广播系统的传输性能,在时域同步正交频分复用(TDS-OFDM)系统中应用空时、空频两种发射分集方法。根据系统信号帧结构的特点,提出了简单易行的发射链路信号配置方法,保持原有链路不变,运算复杂度小。同时,分析了空时、空频两种分集方法的适用范围。仿真结果表明:在慢衰落信道下,两种方法都能提高系统的误码性能,当误码率为10-3时有不低于8dB的分集增益;在快衰落信道下,空时分集性能受D opp ler频移的影响而变得很差,空频分集的增益则与在慢衰落信道时相近。对于不同类型的信道采用合适的发射分集方法,数字电视地面广播系统的传输性能可以得到很大提高。
文摘Space time coding can provide high data rate and performance gain for wireless communication system. Performance comparison of space time trellis codes and space time transmit diversity is carried out under the same bandwidth efficiency in this paper. We also propose some optimum low rate space time trellis codes in quasi static Rayleigh fading chan￣nel. Performance analysis and simulation show that the low rate space time trellis codes outperform space time transmit diversity at the same bandwidth efficiency, and are more suitable for the power limited wireless communication system which has no strict requirement on bandwidth efficiency.
文摘Space-time spreading (STS) and orthogonal transmit diversity (OTD) are towtransmit diversity schemes proposed by cdma2000 standard. In this paper, performance comparisonanalysis of the two transmits diversity schemes in multipath channel under multiuser situation arecarried out. Link level simulation in forward link cdma2000 is performed in IMT-2000 channel.Performance analysis and simulation results show that the performance improvement provided STS overOTD decreases as the increase of propagation path number and decrease of the user number.
