Therefore to solve the noises in the upstream channel and to share the sources of the upstream channels becomes one of the key technologies for hfc system to become a multimedia communication platform 因此，解决上行信道的噪声问题和上行资源共享是hfc网络能否成为一个多媒体业务通信平台的关键技术之一。
To make itself compatible the transmission mode of the conventional catv system , the bandwidth of hfc system is divided into many 8mhz channels , which include downstream and upstream channels 为了兼容传统的有线电视传输模式， hfc网络带宽首先被频分为若干个8mhz的频道，这些频道被统一划分为下行和上行信道。
With regard to modulation , cablemodem adopts qam on downlink channels , and qpsk or the more superior s - cdma on the uplink to achieve a better suppression of noise interference Cablemodem的下行信道采用了qam调制方式，而在上行信道上，为了更好地抑制噪声干扰，通常采用抗干扰性能较好的qpsk或者s - cdma调制技术。
In the end , this paper considered detecting the desired user signal for uplink ds / cdma system . in that case , we need to suppress both mai and inter - chip interference ( ici ) caused by multipath propagation 最后，本文研究了在ds cdma的上行信道中，同时存在多用户干扰和多径传播引起的码间干扰的情况下，对期望用户信号的检测。
The concept of the qos appears in the docsis v1 . 1 . both ieee802 . 14 and docsis , focus in mac protocol design on the upstream channels , i . e . sharing the upstream channels , dealing the services and resolving the contention 无论是ieee802 . 14还是docsis两者mac层协议的设计重点都放在上行信道上，即上行信道的分配，服务调度以及冲突解决等。
With amounts of flight experiment , proved the design could satisfy the demand of large quantities of data in down channel and high precision and reliability of control parameters in up channel 经大量完全自主飞行实验结果表明，所设计的监控系统软件不仅能够满足小型无人机下行信道传输数据量大的监测要求，而且可以确保上行信道控制参数高精度、高可靠性的要求。
4 . the error correcting scheme adopted by mpeg - 2 in dvb system has been fully studied , the feasible error correcting scheme applied in the up - link of dvb system is put forward , and the decoder module used in mpeg - 2 system is designed 详细研究了dvb系统中mpeg - 2所选用的纠错码方案；并且结合实际项目，提出了适用于dvb上行信道的可行的纠错编码方案，设计出了mpeg - 2流中的译码器模块。
With reasonable constraint and the assistant of special - designed pilot sequence for each user , the discrete fourier transform ( dft ) - based uplink channel estimation algorithm can achieve good estimation accuracy without sacrificing much system capacity 在合理约束条件以及为每个用户特殊设计的导频序列辅助下，基于离散傅里叶变换( dft )的上行信道估计算法能够获得较好的估计精度，同时无需牺牲过多的系统容量。
Abstract : the sources and categories of noise about return - path of hfc ( hybrid fiber / coax ) are analyzed , and a few effective methods of reducing noise are presented for different noise , which simultaneously the choice of modulation and multiple access technology is adopted to reduce the noise 文摘:分析了hfc网络上行信道噪声的来源和分类，针对不同的噪声提出几种有效的抑制方法，同时结合上行信道多址接入方式和调制解调方式的选择来抑制噪声。
4 . we propose that the best detection method for the uplink mc - cdma system is decorrelating - parallel interference cancellation ( dec - pic ) multiuser detection , and the best detection method for the downlink mc - cdma system is minimum mean square error combining ( mmsec ) single user detection 提出上行信道mc - cdma的最佳检测方法是解相关-并行干扰抵消多用户检测法( dec - pic ) ，在下行信道mc - cdma的最佳检测方法是最小均方误差合并单用户检测法( mmsec ) 。
