本文選題：無線信道建模 + Trace�。� 參考：《國防科學(xué)技術(shù)大學(xué)》2014年博士論文

【摘要】：無線信道建模是無線通信領(lǐng)域的基礎(chǔ)性技術(shù),它試圖以數(shù)學(xué)模型的方法從紛繁復(fù)雜且看似隨機出現(xiàn)的無線信道傳輸錯誤中,挖掘和認知無線通信過程中錯誤出現(xiàn)的內(nèi)在規(guī)律,并以模型結(jié)構(gòu)和模型參數(shù)的形式定性或者定量地表達這些內(nèi)在規(guī)律,從而為上層協(xié)議的設(shè)計和性能評估提供依據(jù)。本文基于真實無線信道中的測量Trace建立信道模型,并使用信道模型研究目標(biāo)無線信道中具有指導(dǎo)意義的統(tǒng)計規(guī)律,然后將這些規(guī)律應(yīng)用于一種基于編碼的報文比特錯誤率估計方法。本文的主要研究內(nèi)容包括以下四個方面:(1)研究具有重尾特性的無線信道建模問題無線信道的重尾特性符合人們對于無線信道中傳輸錯誤出現(xiàn)規(guī)律的客觀觀察,并且對于上層協(xié)議性能具有一定的影響。因此,建立一個能夠準確反映無線信道重尾特性的信道模型具有十分重要的理論和實踐意義。現(xiàn)有的專門針對重尾信道的模型存在模型結(jié)構(gòu)復(fù)雜,運行時成本高、參數(shù)化過程復(fù)雜等不足。本文從測量Trace的run長度和burst長度互補累積分布函數(shù)入手,提出了一種基于獨立非同分布的隨機過程的重尾信道模型inid。inid模型結(jié)構(gòu)簡單靈活、運行時成本低(一個貝努利試驗),僅包含兩個參數(shù)且參數(shù)化過程簡單。(2)研究通用無線信道建模問題無線信道內(nèi)在的時變特性以及傳輸錯誤出現(xiàn)的隨機性和不可預(yù)測性,導(dǎo)致了無線信道的測量Trace具有多樣化的建模特性。時變的無線信道及其具有不同建模特性的測量Trace加大了無線信道建模的難度。本文從測量Trace的共性入手定義了外部run、內(nèi)部run、錯誤過程等概念,并基于錯誤過程和外部run提出了一種新的Trace表達方法。利用這種新的Trace表達方法,本文提出了一種精確、通用的無線信道模型GEM。GEM模型結(jié)構(gòu)簡單、適用性好、參數(shù)具有明確的物理意義且建模過程與具體測量Trace的建模特性無關(guān)。試驗結(jié)果表明GEM模型能夠精確地刻畫具有不同建模特性的Trace。(3)研究模型驅(qū)動錯誤估計編碼算法錯誤估計編碼(Error Estimating Coding,EEC)是一種基于編碼的報文比特錯誤率估計方法。它的基本思想是發(fā)送端在發(fā)送數(shù)據(jù)中加入少量的冗余信息,接收端基于這些冗余信息估計報文的比特錯誤率。報文的比特錯誤率與無線信道的錯誤特性緊密相關(guān),因此在錯誤估計編碼算法的設(shè)計過程中,考慮無線信道的錯誤特性具有重要的理論和實踐意義。本文結(jié)合基于模型的信道解碼后無線信道錯誤特性分析,提出了模型驅(qū)動錯誤估計編碼算法MEEC。試驗結(jié)果表明MEEC算法能有效克服信道突發(fā)特性和短期記憶特性對于算法估計精度的影響,能以更少的空間開銷獲得更高的估計精度。(4)研究基于信道模型的Smart錯誤估計編碼現(xiàn)有錯誤估計編碼算法的設(shè)計和驗證都基于這樣一個應(yīng)用模式:發(fā)送端在信道編碼前,計算和編碼錯誤估計位;接收端在信道解碼后,重新計算錯誤估計位并估計報文比特錯誤率。基于這種應(yīng)用模式的錯誤估計編碼稱為信道解碼后的錯誤估計編碼。本文首次提出信道解碼前的錯誤估計編碼,即發(fā)送端在信道編碼后、調(diào)制前,計算和編碼錯誤估計位;接收端在解調(diào)后、信道解碼之前,重新計算錯誤估計位并估計報文比特錯誤率。相比信道解碼后的錯誤估計編碼,信道解碼前的錯誤估計編碼的優(yōu)點是接收端不需要信道解碼就可以估計報文比特錯誤率。因為信道解碼比較耗時,所以第二種應(yīng)用模式的實時性更高。本文使用信道模型建模信道解碼前的無線信道并分析目標(biāo)信道的錯誤特性,結(jié)合基于多進制正交幅度調(diào)制(M-QAM)技術(shù)的物理層符號錯誤結(jié)構(gòu),提出了一種針對信道解碼前無線信道的錯誤估計編碼Smart-EEC。試驗結(jié)果表明基于Smart-EEC的EEC算法和MEEC算法很好地實現(xiàn)了估計精度與空間開銷的折中。綜上所述,本文主要針對無線信道建模、基于模型的目標(biāo)信道錯誤特性認知及其在錯誤估計編碼技術(shù)中的應(yīng)用問題展開深入研究。本文的研究豐富了無線信道建模的理論,推動了信道模型與錯誤估計編碼的融合,具有一定的理論意義和應(yīng)用價值。
[Abstract]:Wireless channel modeling is a basic technology in the field of wireless communication. It tries to exploit and recognize the inherent laws of errors in the process of wireless communication in the process of complex and seemingly random wireless channel transmission by means of mathematical models, which are expressed qualitatively or quantitatively in the form of model structure and model parameters. The inherent law provides the basis for the design and performance evaluation of the upper layer protocol. This paper builds a channel model based on the measurement Trace in the real wireless channel, and uses the channel model to study the guiding statistical rules in the target wireless channel, and then applies these rules to a coded bit error rate estimation. The main research contents of this paper include the following four aspects: (1) to study the wireless channel modeling with heavy tail characteristics, the heavy tailing characteristics of the wireless channel conform to the objective observation of the law of transmission error in the wireless channel, and have a certain influence on the performance of the upper layer protocol. The channel model reflecting the heavy tailed characteristics of the wireless channel has very important theoretical and practical significance. The existing model for heavy tailed channel is complex, high cost and complex parameterized process. In this paper, a basis for measuring the run length and burst length of Trace to complement the cumulative distribution function is proposed. The heavy tailed channel model inid.inid model in an independent and non identically distributed random process is simple and flexible, and the cost is low (a Bernoulli test). It contains only two parameters and the process of parameterization is simple. (2) the study of the inherent time-varying characteristics of the wireless channel of universal wireless channel modeling and the randomness and inability of the transmission error. Measurability results in a variety of modeling characteristics of the wireless channel measurement Trace. The time-varying wireless channel and the measurement Trace with different modeling characteristics increase the difficulty of modeling the wireless channel. This paper defines the concepts of external run, internal run, error path and so on from the generality of measuring Trace, and based on the error process and external run extraction. A new method of Trace expression is presented. Using this new Trace expression method, this paper proposes an accurate, universal wireless channel model GEM.GEM model with simple structure, good applicability, a clear physical meaning and the modeling process is independent of the modeling of the specific Trace. The experimental results show that the GEM model can be accurate. The Trace. (3) study of model driven error estimation coding algorithm error estimation coding (Error Estimating Coding, EEC) is a coding based error rate estimation method based on encoded bits. Its basic idea is that the transmitter adds a small amount of redundant information to the transmitted data and the receiver is based on these redundant information. The bit error rate of the message is estimated. The bit error rate of the message is closely related to the error characteristics of the wireless channel. Therefore, it is of great theoretical and practical significance to consider the error characteristics of the wireless channel during the design of the error estimation coding algorithm. The MEEC. test results of the model driven error estimation coding algorithm show that the MEEC algorithm can effectively overcome the influence of the burst characteristics and short-term memory characteristics on the estimation accuracy of the algorithm, and can obtain higher estimation accuracy with less space overhead. (4) the existing error estimation coding algorithm for Smart error estimation coding based on channel model is studied. The design and verification are based on such an application pattern: the transmitter calculates and encodes error estimation bits before channel coding; the receiver recalculate error estimates and estimate the error rate of message bits after channel decoding. Error estimation coding based on this application mode is called error estimation coding after channel decoding. This paper is the first time in this paper. The error estimation code before the channel decoding is proposed, that is, before the channel coding, the error estimation bit is calculated and coded before the channel coding, and the receiver is recalculating the error estimation bit and estimating the error rate of the message before the demodulation, the channel decoding, and the error estimation coding before the channel decoding, and the error estimation before the channel decoding is superior. The point is that the receiver can estimate the bit error rate without the need of channel decoding. Because the channel decoding is more time-consuming, the second application modes are more real-time. This paper uses the channel model to model the wireless channel before the channel decoding and analyzes the error characteristics of the target channel, which is based on the multilevel orthogonal amplitude modulation (M-QAM) technology. The error structure of the physical layer symbol is proposed, and a error estimation coding Smart-EEC. test results for the channel decoding before the channel decoding shows that the Smart-EEC based EEC algorithm and the MEEC algorithm achieve the tradeoff between the estimation precision and the space overhead. In summary, this paper mainly deals with the wireless channel modeling and the model based target letter. This research enriches the theory of wireless channel modeling and promotes the fusion of channel model and error estimation coding, which has some theoretical significance and application value.
【學(xué)位授予單位】：國防科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TN92

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