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CDMA-CSMA多用户通信系统在配电网中的仿真研究
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作者 吴潇 俎云霄 吕玉琴 《计算机工程与应用》 CSCD 北大核心 2007年第28期147-149,共3页
多通道随机通信系统的研究是一个新的课题,在以往的研究中,大多集中在固定分配多址接入方式。引入了随机多址接入技术,以便在突发性事件中保持良好的性能,并采用蒙特卡罗方法对CDMA-时隙式非坚持CSMA多用户通信系统在不同因素影响下的... 多通道随机通信系统的研究是一个新的课题,在以往的研究中,大多集中在固定分配多址接入方式。引入了随机多址接入技术,以便在突发性事件中保持良好的性能,并采用蒙特卡罗方法对CDMA-时隙式非坚持CSMA多用户通信系统在不同因素影响下的网络吞吐量进行了仿真研究。证明了在随机多址接入技术中采用CDMA技术,可以明显改善系统的性能。 展开更多
关键词 DS/CDMA 时隙式非坚持CSMA 电力线网络 信道比特误码率
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CDMA时隙式非坚持CSMA多用户通信系统在电力线网络中的仿真研究
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作者 吴潇 俎云霄 吕玉琴 《数字通信世界》 2007年第1期64-66,共3页
多通道随机通信系统的研究是一个新的课题,在以往的研究中,大多集中在固定分配多址接入方式,而本文引入了随机多址接入技术,以便在突发性事件中保持良好的性能,并采用蒙特卡罗方法对CDMA-时隙式非坚持CSMA多用户通信系统在不同因素影响... 多通道随机通信系统的研究是一个新的课题,在以往的研究中,大多集中在固定分配多址接入方式,而本文引入了随机多址接入技术,以便在突发性事件中保持良好的性能,并采用蒙特卡罗方法对CDMA-时隙式非坚持CSMA多用户通信系统在不同因素影响下的网络吞吐量进行了仿真研究,证明了在随机多址接入技术中采用CDMA技术,可以明显改善系统的性能。 展开更多
关键词 DS/CDMA 时隙式非坚持CSMA 电力线网络 信道比特误码率
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MAKING FULL USE OF OUTDATED CHANNEL ESTIMATES FOR BLOCK BY BLOCK ADAPTIVE MODULATIONS
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作者 Shan Xiaohong Bi Guangguo 《Journal of Electronics(China)》 2007年第1期54-59,共6页
This paper explores the potential to use accurate but outdated channel estimates for adaptive modulation. The work is novel in that the research is conditioned on block by block adaptation. First,we define a new quant... This paper explores the potential to use accurate but outdated channel estimates for adaptive modulation. The work is novel in that the research is conditioned on block by block adaptation. First,we define a new quantity,the Tolerable Average Use Delay (TAUD),which can indicate the ability of an adaptation scheme to tolerate the delay of channel estimation results. We find that for the variable-power schemes,TAUD is a constant and dependent on the target Bit Error Rate (BER),average power and Doppler frequency; while for the constant-power schemes,it depends on the ad-aptation block length as well. At last,we investigate the relation between the delay tolerating per-formance and the spectral efficiency and give the system design criterion. The delay tolerating per-formance is improved at the price of lower data rate. 展开更多
关键词 Adaptive modulation Block by block adaptation Channel estimation Spectral efficiency
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Double-Space-Cooperation Method for Increasing Channel Capacity
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作者 JIAO Bingli LI Dou 《China Communications》 SCIE CSCD 2015年第12期76-83,共8页
Shannon channel capacity theorem poses highest bit-rate of error free transmission over additive white Gaussian noise channel.In addition,he proved that there exists channel code that can theoretically achieve the cha... Shannon channel capacity theorem poses highest bit-rate of error free transmission over additive white Gaussian noise channel.In addition,he proved that there exists channel code that can theoretically achieve the channel capacity.Indeed fortunately,the latter researchers found some practical channel codes approaching the channel capacity with insignificant losses of spectral efficiency under ignorable bit error rate(BER).The authors note,in general,that bits of the channel codes are not independent of each other in code space.Further,we note that the modulated symbols are not independent among them,as well,in Euclidean Space.By exploiting a usage of the dependencies jointly to signal design,we can transmit two independent signal streams through an additive white Gaussian channel and separate them in Euclidean space at the receiver.The capacity of this approach is found larger than that of Shannon capacity in the same channel assumptions.The numerical results confirm the theoretical procedures. 展开更多
关键词 Euclidean transmit receiver symbol parity latter separate coded additive losses
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