THE THEORETICAL BER PERFORMANCE ANALYSIS OF A COOPERATIVE DIVERSITY SCHEME IN FREQUENCY SELECTIVE FADING CHANNEL

A novel cooperative diversity scheme based on Distributed Space-Time Block Coding and Multi-Carrier Code Division Multiple Access (DSTBC-MC-CDMA) is proposed which works well in frequency selective fading channels with multiple single-antenna users. And an analytical error model is established to describe the symbol decoding errors between interusers, based on which a close form expression for theoretical Bit Error Rate (BER) performance of the scheme is derived to analyze the influence of the interuser decoding errors on the BER performance of the scheme. Then simulation is complimented to verify the analytic result above, which also shows that the BER performance of DSTBC-MC-CDMA outgoes that of non-cooperative MC-CDMA with considerable gains. Further- more, the simulations coincide with the theoretical results well.

一种协同分集方案的误码性能分析

协同分集(cooperative diversity)技术通过为网络中某些单天线用户寻找若干个用户作为"伙伴",并共享彼此天线,形成虚拟的多天线阵列,来实现多天线分集,结合分布式空时分组编码(Distributed Space Time Block Code,DSTBC),可以有效地提高系统性能.多载波码分多址(Multi-Carrier Code Division Multiple Access,MC-CDMA)技术将数据调制到各个子载波上发送,可以有效地抵抗信道频率选择性衰落的影响.本文提出了无线网络中频率选择性衰落信道环境下的一种基于分布式空时分组码和MC-CDMA的协同发射分集方案,建立了协同用户间的误码表示模型,基于该模型推导了协同分集方案误码性能的理论表达式,并分析了协同用户间的平均解码差错概率对系统方案误码性能的影响,同时给出了仿真结果.结果表明,DSTBC-MC-CDMA相对于未协同的MC-CDMA系统获得了明显的性能增益,同时仿真也较好地验证了理论结果.

参松养心胶囊对儿茶酚胺敏感性室性心动过速作用的探讨

儿茶酚胺敏感性室性心动过速（CPVT）是恶性程度最高的遗传性心脏离子通道疾病,以情绪激动或运动诱发的双向或多形性室性心动过速为特征,常常伴有晕厥,甚至发生猝死,多发生于QT间期正常而无器质性心脏病的儿童或青少年;患病率约为1/10000,猝死率高达30%~50%,给患者及家庭成员造成了严重的心理负担及精神创伤。目前的治疗方案主要有β受体阻滞剂、钙通道阻滞剂、钠通道阻滞剂、复律除颤器、左心交感神经切除术等,各种治疗均有一定效果,但其伴随的诸多副作用是影响患者生存质量的重大障碍,不容忽视;因此寻找既有效又安全的药物尤为重要。参松养心胶囊是我国临床常用抗心律失常中成药,对多离子通道有协同阻滞作用,安全性高,副作用少;但用于CPVT的治疗尚未见报道,文章目的是对参松养心胶囊的多离子通道的协同阻滞作用对CPVT患者能否中止或减少CPVT的发生率进行探讨。