为了保障SCADA(Supervisory Control And Data Acquisition,监视控制与数据采集)系统调度中心与现场间远程通讯的稳定性,为远程通讯提供可靠的通讯信道,本文利用冗余技术HSRP(Hot Standby Redundancy Protocol,热备冗余协议)和路由技术E...为了保障SCADA(Supervisory Control And Data Acquisition,监视控制与数据采集)系统调度中心与现场间远程通讯的稳定性,为远程通讯提供可靠的通讯信道,本文利用冗余技术HSRP(Hot Standby Redundancy Protocol,热备冗余协议)和路由技术EIGRP(Enhanced Interior Gateway Routing Protocol,加强型内部网关路由协议),设计了两种双信道冗余方案:单端路由器冗余方案与双端路由器冗余方案。最后介绍了一个使用双端路由器冗余方案的应用案例。展开更多
The enhanced variable rate codec (EVRC) is a standard for the 'Speech ServiceOption 3 for Wideband Spread Spectrum Digital System,' which has been employed in both IS-95cellular systems and ANSI J-STC-008 PCS ...The enhanced variable rate codec (EVRC) is a standard for the 'Speech ServiceOption 3 for Wideband Spread Spectrum Digital System,' which has been employed in both IS-95cellular systems and ANSI J-STC-008 PCS (personal communications systems). This paper concentrateson channel decoders that exploit the residual redundancy inherent in the enhanced variable ratecodec bitstream. This residual redundancy is quantified by modeling the parameters as first orderMarkov chains and computing the entropy rate based on the relative frequencies of transitions.Moreover, this residual redundancy can be exploited by an appropriately 'tuned' channel decoder toprovide substantial coding gain when compared with the decoders that do not exploit it. Channelcoding schemes include convolutional codes, and iteratively decoded parallel concatenatedconvolutional 'turbo' codes.展开更多
This paper presents a CRC (Cyclic Redundancy Check)-aided turbo equalization approach to reduce the computational complexity. In this approach,CRC code bits are padded to the end of each transmit block,and a cyclic re...This paper presents a CRC (Cyclic Redundancy Check)-aided turbo equalization approach to reduce the computational complexity. In this approach,CRC code bits are padded to the end of each transmit block,and a cyclic redundancy check is performed after decoding each block at the receiver end. If the check sum is zero,which means the receive block is correct,the corresponding LLRs (Log Likelihood Ratios) of this block are set high reliable values,and all the computations corresponding to this block can be cancelled for the subsequent outer iterations. With a lower computational complexity the proposed approach can achieve the same as or even better performance than the conventional non-CRC method.展开更多
文摘为了保障SCADA(Supervisory Control And Data Acquisition,监视控制与数据采集)系统调度中心与现场间远程通讯的稳定性,为远程通讯提供可靠的通讯信道,本文利用冗余技术HSRP(Hot Standby Redundancy Protocol,热备冗余协议)和路由技术EIGRP(Enhanced Interior Gateway Routing Protocol,加强型内部网关路由协议),设计了两种双信道冗余方案:单端路由器冗余方案与双端路由器冗余方案。最后介绍了一个使用双端路由器冗余方案的应用案例。
文摘The enhanced variable rate codec (EVRC) is a standard for the 'Speech ServiceOption 3 for Wideband Spread Spectrum Digital System,' which has been employed in both IS-95cellular systems and ANSI J-STC-008 PCS (personal communications systems). This paper concentrateson channel decoders that exploit the residual redundancy inherent in the enhanced variable ratecodec bitstream. This residual redundancy is quantified by modeling the parameters as first orderMarkov chains and computing the entropy rate based on the relative frequencies of transitions.Moreover, this residual redundancy can be exploited by an appropriately 'tuned' channel decoder toprovide substantial coding gain when compared with the decoders that do not exploit it. Channelcoding schemes include convolutional codes, and iteratively decoded parallel concatenatedconvolutional 'turbo' codes.
基金Supported in part by the National Natural Science Foundation of China (No.60496311).
文摘This paper presents a CRC (Cyclic Redundancy Check)-aided turbo equalization approach to reduce the computational complexity. In this approach,CRC code bits are padded to the end of each transmit block,and a cyclic redundancy check is performed after decoding each block at the receiver end. If the check sum is zero,which means the receive block is correct,the corresponding LLRs (Log Likelihood Ratios) of this block are set high reliable values,and all the computations corresponding to this block can be cancelled for the subsequent outer iterations. With a lower computational complexity the proposed approach can achieve the same as or even better performance than the conventional non-CRC method.
