Font Size: a A A

Analysis And Process Methods For Multichannel Mutual Interference

Posted on:2009-03-31Degree:DoctorType:Dissertation
Country:ChinaCandidate:J M HuangFull Text:PDF
GTID:1118360302469122Subject:Signal and Information Processing
Abstract/Summary:PDF Full Text Request
Multiple wireless channels such as short wave, ultrashort wave and microwave channel are main signal paths for tactical communication. It is a kind of open natural resource, which will not be consumed, and will be wasted if not properly utilized. However, it has different features from other natural resources.If not properly designed or used, chaos in order of electric wave can be caused, especially, sever mutual interference can occur when multichannel transport devices are put together in a limited space.Mutual interference is a kind of electromagnetic phenomenon arising within systems or between systems. That is, the interference caused by one transmitter to other receivers when it is working normally. With the emergence of more and more telecommunication methods and the increase of user demand to different services, the problem of lack of spectrum resource intensifies, while the other problem of mutual interference becomes more remarkable. In tactical communication, mutual interference is very common, and it greatly affects the performance of communication. Serious error or system failure may be aroused in worst case. Therefore, electromagnetic interference is becoming a huge barricade on the development of tactical communication.This paper focuses on the problem of electromagnetic interference confronted in tactical communication system. It studies the causes and tries to find solutions of multichannel mutual interference. Briefly speaking, it covers the following issues:1. Considering the features of tactical communication, the concept and content of multichannel interference are proposed. The limitation of current research is pointed out, and the present situation of multichannel electromagnetic spectrum distribution is analysed. It also illustrates the phenomenon of interference and to what extent the performance of channel is affected. The model of multichannel radiation and composition of electromagnetic field is analyzed, as well as the short distance antenna characteristic and interference effect of long distance receiver. A series of models of multichannel mutual interference is established.2. According to the types and characteristics of multichannel mutual interference, a three-step solution of dodge, mitigation and notch is proposed. By analyzing the causes and characteristics of multichannel mutual interference, layering and classifying various interference, from the angle of the top perspective of tactical communication, it introduces the categorization, object-defining, synthesizing 3-step solution. In the first step, frequency assigning technique is adopted to effectively dodge mutual interference and solve the quasi-interference problem of collocation system, In the second step, multiple mitigation methods are synthesized to alleviate interference. The last step employs narrowband-notch method to implement cancellation of strong power interference and solve the clogging quasi-interference problem.3. Aiming at the problem of collocation interference, a dodging method is introduced based on frequency assigning. We have analyzed the particularity, principle and procedure of multichannel frequency assigning, and discussed the relation of frequency compatibility and interference dodging optimism. The model of multichannel frequency assigning is established and diverse algorithms are compared, a two-step synthesizing collocation interference dodging method is proposed thereafter. This method bases on the principles of minimal cover and backstep assign. The implementation process of interference dodge by frequency assigning is deduced while correctness and effectivity of the method are proved as well.4. Aiming at the problem of multichannel cosite effect, a mitigation technique based on multiple methods is introduced. The paper discusses several schemes such as high-isolations collocation antenna, collocation filtering and multipath coupling to solve collocation sensitivity decrease. The effect of synthesizing multiple methods is illustrated. On the other hand, aiming at the frequency collision problem confronted in FH/CDMA networking, a mitigation method based on few-hit zone (FHZ) sequences is proposed. The concept and construction of the sequences are discussed, and its excellent performance in condition of quasi-synchrony is proved. Both experiments and simulations show that not only does FHZ sequence have little collocation interference characteristic like NHZ sequence, but it also provides more user address, and cosite interference is therefore reduced effectively.5. Aiming at the problem of strong power narrowband interference, the paper discusses the harmfulness and particularity of interference caused by narrowband channel clogging wideband channel. An adaptive narrowband notch method is proposed to cancel such interference. Based on the principle of minimum signal loss, it establishes the model of coaxial-cavity resonator circuit by transformation and analysis of lumped parametric and distributed parametric filter. We implement and experiment the circuit designed associating with wideband FH system. Methods of engineering design and implementation of narrowband notch filter are discussed. Engineering experiments indicate that this method effectively solve the clogging quasi-interference problem in multichannel.In conclusion, this paper presents in-depth research and exploration on multichannel mutual interference. Relative achievements contribute in system design and construction method of present day tactical communication, and serves as important support and reference for the development and creativity of military communication.
Keywords/Search Tags:Tactical communication, multichannel, frequency aliasing, frequency collision, collocation interference, cosite interference, narrowband jam-interference, frequency assignment, interference dodge, interference mitigation, adaptive narrowband notch
PDF Full Text Request
Related items