本文關鍵詞： 物理層安全 安全編碼 無線信道特征 等效信道模型 人工噪聲　出處：《解放軍信息工程大學》2014年碩士論文　論文類型：學位論文

【摘要】：物理層安全利用無線信道多樣性以及通信雙方信道特征的唯一性、互易性防止信息在通信鏈路底層泄露,是一種針對無線通信特點設計的信息安全保障方法。安全編碼作為物理層安全的關鍵技術之一,將編碼的糾錯特性與無線信道特征有機結合,差異化合法接收者與第三方竊聽者的接收性能,實現合法通信雙方信息的安全可靠傳輸。但是,目前的安全編碼研究還存在以下問題:1)對信道特征的差異性利用不充分,導致安全編碼獲得的安全增益受限;2)缺乏安全編碼與傳輸技術的聯(lián)合設計,導致安全編碼效率及系統(tǒng)功率利用率降低。本文依托國家自然科學基金項目,對物理層安全編碼技術展開專門研究。針對上述問題,論文首先提出了兩種與合法信道時域特征強耦合的安全編碼方法:基于信道衰落幅度差異的物理層安全編碼方法和基于信道特征擾動相位的物理層安全編碼方法。然后研究了安全編碼與人工噪聲方法的聯(lián)合設計,以提高安全編碼的效率及系統(tǒng)功率利用率。主要研究內容包括:1、提出了基于信道衰落幅度差異的物理層安全編碼方法。首先,證明了信道能量相同條件下,低密度校驗碼中私密信息節(jié)點傳輸時所對應的信道衰落幅度越小,越有利于該處的信息正確恢復;然后選取合法信道衰落幅度最小的位置作為私密信息位,并將私密信息隱藏在隨機序列中,形成有利于合法接收者譯碼的條件;再結合私密信息置亂,將竊聽者的譯碼殘余比特錯誤擴散到整個碼字中。仿真結果表明,該方法提高了竊聽者的誤比特率,相比于僅信息置亂的方法,安全間隙縮小了5dB。2、提出了基于信道特征擾動相位的物理層安全編碼方法。首先,通過合法信道衰落幅度與相位擾動權值幅度信息的乘積,確定對發(fā)射符號進行相位隨機擾動的邊界范圍;然后,以發(fā)射端在平均功率約束下隨機產生的幅度信息,連同在相位擾動邊界范圍內隨機選取的相位信息,共同構成相位擾動權值;最后,以所得的相位擾動權值對每個待發(fā)射符號進行預編碼,使得合法接收者在相位擾動下仍具有穩(wěn)定的抗噪聲性能,而竊聽者接收符號的相位信息模糊無法正確譯碼。仿真結果表明,在相同發(fā)射功率和信道噪聲的情況下,竊聽者的誤比特率接近0.5。3、提出了基于等效信道模型的安全編碼與傳輸聯(lián)合設計方法。首先建立了無線物理層等效信道模型,分析了影響安全編碼與人工噪聲傳輸方法性能的關鍵參數;然后定量描述了人工噪聲方法在不同誤比特率門限下加權矢量和噪聲矢量對等效信道特征的影響,以及不同等效信道特征對安全編碼誤比特率門限的影響,建立起安全編碼與人工噪聲之間的緊密聯(lián)系;最后,以最大化私密信息碼率為目標設計出兩者的聯(lián)合優(yōu)化算法。仿真結果表明,該方法能使私密信息碼率達到0.43,提高了安全編碼效率;安全性余量相比0.35sR?時簡單級聯(lián)的方法縮小約3dB,提高了系統(tǒng)的功率利用率。
[Abstract]:The only physical layer security using wireless channel diversity and communication channel characteristics, the reciprocity in the bottom to prevent information communication link leak, is a kind of information security method of wireless communication. The design characteristics of security encoding as one of the key technologies of physical layer security, combining the characteristics of the error correction encoding and wireless channel characteristics the receiving performance difference of legitimate receiver and third party eavesdropper, to achieve safe and reliable transmission of information between two legal parties. However, there are the following problems of current safety encoding: 1) differences in utilization of channel characteristics is not sufficient, resulting in security gain restricted security encoding obtained; 2) combined with the lack of safety design encoding with the transmission technology, which leads to the decrease of power efficiency and safety rate of encoding system used. Based on the National Natural Science Fund project, the safety of the physical layer encoding The research on the technology. Aiming at the above problems, this paper put forward two kinds of security encoding method and legitimate channel characteristics in time domain coupling: physical layer based on the channel fading amplitude differences in the safety encoding method and based on the physical layer channel characteristics of phase perturbation method. Combined with the design of security encoding and security of encoding and artificial noise method in order to improve the efficiency, power system security and encoding efficiency. The main research contents include: 1, the physical layer channel fading amplitude difference encoding method based on security. First of all, proved that the channel can amount under the same conditions, the channel of low density parity check codes in the transmission of private information node corresponding to the fading amplitude is small the more conducive to the correct recovery; and then select the legitimate channel fading amplitude minimum position as private information, and private information hidden in random order In the column, conducive to the formation of the legitimate receiver decoding conditions; combined with private information scrambling, the residual bit error diffusion decoding eavesdropper to the entire codeword. The simulation results show that this method improves the eavesdropper bit error rate, compared to the only information scrambling method, safety clearance reduced by 5dB.2, put forward the physical layer channel disturbance phase encoding method based on security. First, the product through legal channel fading amplitude and phase perturbation amplitude weight information, determine the phase boundary of random disturbance transmitted symbols; then, the amplitude information at the transmitter at random from the average power constraints, together with the phase perturbation phase boundary information in the range of randomly selected, together constitute the phase perturbation weights; finally, the phase perturbation weights to each transmitted symbol to be pre encoding, the legitimate receiver in phase Who still has the anti noise performance and stable perturbations, the eavesdropper receives a symbol phase information fuzzy cannot correct decoding. The simulation results show that under the same transmit power and channel noise, the bit error rate of the eavesdropper is close to 0.5.3, puts forward the safety encoding and joint design method of equivalent transmission channel model based on first. Wireless physical layer equivalent channel model is established, and analyzed the key parameters affecting the performance of security encoding and artificial noise transmission method; and then describe the artificial noise method in different bit error rate threshold weighted vector and the noise vector of the equivalent channel characteristics, and different characteristics to affect the safety of the equivalent channel encoding bit error rate threshold and establish close relationship between safety and artificial noise encoding; finally, to maximize the private information rate is designed for joint optimization of the two The simulation results show that the private information rate is 0.43 and the security coding efficiency is increased by this method. The security margin is reduced by about 3dB compared to the 0.35sR concatenation method, and the power utilization ratio of the system is improved.

【學位授予單位】：解放軍信息工程大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN92

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本文編號：1529472