摘要
论文对HFC-CATV上行信道噪声特性和抗干扰技术进行了研究。首先分析了上行信道噪声漏斗效应现象，讨论了HFC网络中噪声干扰的来源、成因和特点，其次以数学公式及物理定律为理论基础建立了上行信道噪声模型，接着研究上行信道噪声对QPSK、16QAM调制技术的影响。分析与仿真表明，冲击脉冲的出现频度越高或每个冲击脉冲的能量越大，则误码性能劣化越显著；而窄带连续波干扰的特征函数与高斯白噪声一样，所以误码曲线的形状也一样，随着比特信噪比的增大，误码率下降很快，但随着窄带连续干扰波数目的增多，误码性能明显变差。通过分析得到QPSK系统的抗干扰性能要优于16QAM。最后，采取了同步码分多址技术和非线性自适应滤波技术来抑制冲击干扰和窄带连续波干扰。
The noise characteristics and the anti-interference techniques of the HFC-CATV upstream channel are studied in this thesis. Firstly, the noise "funnel effect" phenomenon is analyzed and the sources, the cause and the characteristics of the noise interference in the HFC network are discussed. Secondly, based on the related mathematical formulas and physical laws, the noise models of the upstream channel are set up. Then, the effects that the noises in the upstream channel have on the QPSK and 16QAM modulation techniques are studied. The simulation results show that the more frequently the impulse emerges or the greater the energy of each impulse, the more obviously the bit error rate degrades . The characteristic function of the narrow-band continuous wave interference is the same as that of gaussian white noise, so the shapes of their bit error graph are the same. With the increase of the Eb/N0, the bit error rate declines quickly, but with the increase of the number of the narrow-band continuous wave, the performance on the bit error rate degrades greatly. The study results have shown that the anti-interference performance of the QPSK system is better than that of the 16QAM system. Finally, The S-CDMA and the adaptive nonlinear filter techniques are used to restrain the impulse interference and the narrow-band continuous wave interference.
引文
1 曹志刚，钱亚生．现代通信原理．北京：清华大学出版社，1992
2 祁玉生，邵世祥．现代移动通信系统．北京：人民邮电出版社，1999
3 郭金生．双向HFC网上行通道的噪声与干扰．电视技术．1999(5)：39-41
4 韦乐平．通向宽带通信的新途径—HFC网．电信科学．1996．12(5)：3-8
5 高飞，张芸．HFC接入网技术及其信道噪声分析．电视技术．2001(5)：34-36
6 蔡文杰，苏祥芳，王延平．光纤同轴电缆混合网技术．武汉大学学报．2000．46(5)：617-620
7 黄吴明．有线电视技术．北京：北京广播学院出版社，1992
8 王胜坤等．HFC网络上行信道的噪声及干扰．中国有线电视．1998(7)
9 韦乐平．光同步数字传输网．北京：人民邮电出版社，1993
10 窦剑，吴庚生．基于HFC网的宽带业务接入及其解决方案．电视技术．2000(9)：17-21
11 王新梅．纠错码与差错控制．北京：人民邮电出版社，1989
12 杨东生，张金艺，林如俭．码分多址在HFC网中的应用．电视技术．2000(11)：22-24
13 赵问道，宋耀光，姚庆栋．同轴电缆网络上行信道噪声漏斗效应及其对调制技术的影响分析．浙江大学学报．1999．33(5)：535-539
14 王立宁，乐光新，詹菲．MATLAB与通信仿真．北京：人民邮电出版社，2000
15 张力军，张宗橙，郑宝玉等译．数字通信．第三版．北京：电子工业出版社，2002
16 沈振元，聂志泉，赵雪荷．通信系统原理．陕西：西安电子科技大学出版社，2002
17 孙立新，刑宁霞．CDMA(码分多址)移动通信技术．北京：人民邮电出版社，1996
18 景新幸，周萍，段晓雪．HFC上行信道的QPSK信号窄带干扰抑制．电视技术．2001(9)：44-47
19 罗钦骑，容太平，黄铁侠．有线电视光纤同轴混合网上行通道噪声特性．华中理工大学学报．1997(10)：83-86
20 马秀莲，李廷芳，吕淑香编译．数字通信差错控制技术．中国铁道出版社，1991
21 张文生，周强等译．有线电视宽带HFC接入网回传系统．中国广播电视出版社，1999
22 陈尚勤，李晓峰．快速自适应信息处理．北京：人民邮电出版社，1993
23 孙红雨，杜丽冰．FTF算法应用于扩频信号中BPSK型干扰抑制的探讨．环境技
术．1997(4)：19-21
24 徐娟，覃团发．DS／CDMA通信系统仿真的研究[J]．上海铁道大学学报．1999．21(4)
25 Miller M D. A secenario for the deployment of interactive multimedia cable television system in the United States in the 1990's [J]. Proc of IEEE,1994,82(4):585～589
26 Charles A Eldering,Nageen Himayat,and Floyd M. Gardner. CATV Return Path Characterization for Reliable Communications. IEEE Commun. Mag. 1995(8):62-69
27 John G.Proakis. "Digital Communications", Third Edition,McGraw-Hill,1995
28 Wang hengzhe. Building of Hybrid Fiber Coaxial.Technology of Telecommunication. 1998(10):14-15
29 Yvo L.C. de Jong,Robert P.C. Wolter et. A CDMA Based Bi-directional Communication System for Hybrid Fiber-Coax CATV Network. IEEE TRANSACTIONS ON BROADCASTING.vol.43.No.2 June,1997
30 Hsu,F.M.and Giordano,A.A.,Digital Whitening Techniques for Improving Spread Spectrum Communication Performance in the Presence of Narrow band Jamming and Interference. IEEE Trans.Communication,vol COM-26 1978,pp209-216
31 Gang u,K.Mukumoto and A.Fukuda. Analysis of an integrated voice and data transmission system using packet reservation multiple access. IEEE Trans.Vel.Technol.,Vol.43.No.2,pp289-297,May 1994
32 Suming Ju and Guangguo Bi. Method for eliminating narrowband shortwave interference in upsteam channel of HFC. ELECTRONICS LETTERS. Vol. 34. No. 9, pp852-853, 30th April 1998
33 Viter Andrew J. CDMA: Principles of Spread Spectrum Communication. The Peoples Post & Telecommunication Publishing, 1995
34 Simon Haykin. Adaptive Filter Theory.Third Edition. 电子工业出版社. 1998
35 Stephen G. Wilson. Digital Modulation and Coding. 电子工业出版社. 1998
36 Perkins Stephen,Gatherer Alan. Two-way Broadband CATV-HFC Networks: State-of-the-art and Future Trends. ComputerNetworks,1999,31(4)
37 Blahut R E. Theory and Practice of Error Control codes.Addison-Wesley, 1983
38 Schaner P T. Two-Way Cable Television System Characterization.Philadelphia,SPIE Proc.,1995,2609:94-104
39 Ron Hranc. Impulsa Noise In Two-Way Systems. COMMUNICATIONS
TECHNOLOGY,JULY 1996
40 Wen-Rong Wu and Fu-Fuang Yu. New Nonlinear Algorithms for Estimating and Suppressing Narrowband Interference in DS Spread Spectrum System. IEEE Transactions on Communications Vol. 44. No. 4,April. 1996,pp508-515
41 Raskin Donald,Stoneback Dean. Return System for Hybrid Fiber/Coax Cable TV Networks Prentice Hall Inc. 1999
42 Wolters R P C. Characteristics of Upsteam Channel Noise in CATV-networks[J]. IEEE Transactions on Broadcasting, 1996:328-332