【摘要】：隨著信息社會(huì)的快速發(fā)展,對(duì)于海洋的研究和開(kāi)發(fā)越來(lái)越受到人們的重視,因此水下通信技術(shù)的研究成為了當(dāng)今海洋資源開(kāi)發(fā)、海洋環(huán)境的勘測(cè)以及軍事戰(zhàn)略的重要組成部分,成為了各國(guó)科研研究的熱點(diǎn)。 水聲信道因?yàn)槠鋷捰邢�、多徑干擾嚴(yán)重、強(qiáng)噪聲干擾、頻率選擇性衰落等特點(diǎn)使得水聲信道成為了迄今為止無(wú)線通信中最復(fù)雜多變的通信信道之一。線性調(diào)頻擴(kuò)頻技術(shù)不僅具有一般的擴(kuò)頻通信技術(shù)所共有的強(qiáng)抗干擾、抗衰落、極低的截獲率、高保密性等優(yōu)點(diǎn),而且具有更好的抗多普勒頻移、抗深度衰落性能。上述的優(yōu)點(diǎn)使得線性調(diào)頻擴(kuò)頻技術(shù)更加適合于水聲通信技術(shù)的研究。 論文的主要工作如下： 1.對(duì)線性調(diào)頻信號(hào)的擴(kuò)頻特性、較強(qiáng)的抗干擾和抗噪特性、良好的自相關(guān)特性、抗多徑等性能進(jìn)行了分析。然后,系統(tǒng)地介紹了基于線性調(diào)頻擴(kuò)頻的水聲通信系統(tǒng)的基本原理和特點(diǎn),分析了CSS_BOK擴(kuò)頻通信系統(tǒng)的優(yōu)點(diǎn)和缺陷。 2.對(duì)基于CSS_BOK的三種高階水聲通信系統(tǒng)的基本原理以及性能進(jìn)行了較為全面的分析和仿真,并對(duì)于三種高階調(diào)制系統(tǒng)從抗噪性、抗多徑及載波偏移等角度進(jìn)行了較為詳細(xì)的分析。 3.介紹了基于CSS技術(shù)的三種多址接入技術(shù),包括多載波多址技術(shù)、時(shí)間交疊多址技術(shù)以及基于FRFT變換的多調(diào)頻率多址接入技術(shù)。并對(duì)其在水聲信道中的性能進(jìn)行了不同用戶數(shù)條件下的仿真和分析。 4.本文構(gòu)架了基于DM-BPSK、π/4-DM-DQPSK兩種制式的水聲網(wǎng)絡(luò)仿真平臺(tái),該平臺(tái)在仿真中加入上述兩種調(diào)制方式和Bellhop射線模型,對(duì)淺海水聲信道進(jìn)行建模,在此基礎(chǔ)上結(jié)合進(jìn)行水聲網(wǎng)絡(luò)MAC協(xié)議仿真,研究傳輸范圍變化對(duì)系統(tǒng)性能的影響。最后通過(guò)對(duì)仿真結(jié)果的分析和總結(jié),仿真結(jié)果顯示與水聲信道的特性相符,對(duì)水下組網(wǎng)和MAC協(xié)議的改進(jìn)具有一定的指導(dǎo)意義。
[Abstract]:With the rapid development of information society, people pay more and more attention to the research and development of the ocean. Therefore, the research of underwater communication technology has become an important part of the marine resources development, marine environment survey and military strategy. It has become the hot spot of scientific research all over the world. Underwater acoustic channel has become one of the most complex and changeable communication channels in wireless communication because of its limited bandwidth, serious multipath interference, strong noise interference and frequency selective fading. LFM spread spectrum technology not only has the advantages of strong anti-interference, anti-fading, extremely low interception rate and high security, but also has better anti-Doppler frequency shift and anti-depth fading performance. The advantages above make the LFM spread spectrum technology more suitable for underwater acoustic communication. The main work of this paper is as follows: 1. The spread spectrum characteristics, strong anti-jamming and anti-noise characteristics, good autocorrelation characteristics and anti-multipath characteristics of LFM signal are analyzed. Then, the basic principle and characteristics of underwater acoustic communication system based on LFM spread spectrum are introduced systematically, and the advantages and disadvantages of CSS_BOK spread spectrum communication system are analyzed. 2. The basic principle and performance of three high order underwater acoustic communication systems based on CSS_BOK are analyzed and simulated. The anti-multipath and carrier offset angles are analyzed in detail. 3. This paper introduces three kinds of multiple access technologies based on CSS technology, including multiple carrier multiple access technology, time overlapping multiple access technology and multiple frequency multiple access technology based on FRFT transform. Its performance in underwater acoustic channel is simulated and analyzed under the condition of different number of users. 4. In this paper, the underwater acoustic network simulation platform based on DM-BPSK, 蟺 / 4-DM-DQPSK is constructed. The above two modulation modes and the Bellhop ray model are added to the simulation to model the acoustic channel in shallow water. Based on the simulation of underwater acoustic network MAC protocol, the influence of transmission range on system performance is studied. Finally, by analyzing and summarizing the simulation results, the simulation results show that the simulation results are consistent with the characteristics of underwater acoustic channel, which has certain guiding significance for the improvement of underwater networking and MAC protocol.
【學(xué)位授予單位】：廈門(mén)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TN929.3

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本文編號(hào)：2384224