本文選題：多輸入多輸出正交頻分復(fù)用 + 峰均功率比抑制��； 參考：《哈爾濱工程大學(xué)》2014年碩士論文

【摘要】：淺海水聲信道載波頻率較低、多徑干擾較強(qiáng)及高背景噪聲的特性使其成為迄今為止通信最為困難的無線信道,并且水聲通信中可利用的帶寬資源非常有限。因此,尋找在提升信道容量的同時具有抗多徑干擾能力的通信方式,是水聲通信研究者們關(guān)注的重點。多輸入多輸出(MIMO)技術(shù)能夠成倍提升通信系統(tǒng)容量及頻帶利用率,而無需增加系統(tǒng)的帶寬,正交頻分復(fù)用(OFDM)技術(shù)的抗碼間干擾能力出眾,在水聲通信中將二者結(jié)合的方案成為近年來水聲通信的新熱點。MIMO-OFDM系統(tǒng)由于采用多載波調(diào)制方式,存在著峰均功率比(PAPR)較高的缺陷,這不但限制了系統(tǒng)對于發(fā)射功率的充分利用,而且提高了對功率放大器動態(tài)范圍的要求,增加了系統(tǒng)成本,限制了MIMO-OFDM水聲通信系統(tǒng)的進(jìn)一步發(fā)展。因此,在信號進(jìn)入放大器前抑制其峰均功率比顯得至關(guān)重要。本文在回顧了 MIMO-OFDM系統(tǒng)中現(xiàn)有不同種類的峰均比抑制技術(shù)的基礎(chǔ)上,深入研究了選擇性映射(SLM)技術(shù),論文主要的研究工作如下:1.仿真分析比較了不同種類的峰均比抑制技術(shù),對其應(yīng)用于水聲通信中的可行性與優(yōu)缺點進(jìn)行了分析,為后文改進(jìn)算法的提出奠定基礎(chǔ)。2.針對SLM峰均比抑制技術(shù)需要傳遞邊帶信息、且冗余量較大的缺點,結(jié)合淺海水聲信道的稀疏性,提出了兩種基于信道檢測的無邊帶信息改進(jìn)SLM算法,設(shè)計了基于時域內(nèi)插和壓縮感知的兩種相位序列檢測器。改進(jìn)SLM算法采用的相位序列檢測器的核心思想是通過對信道特征的分析提取,實現(xiàn)對所選加擾相位序列的自主識別。仿真實驗表明,上述兩種改進(jìn)SLM算法與接收端邊帶信息已知時的SLM算法在系統(tǒng)的誤比特率(BER)性能上不相上下;經(jīng)水池實驗驗證,改進(jìn)算法可在信道狀態(tài)信息及邊帶信息均未知的情況下完成相位序列序號的準(zhǔn)確檢測,保證了通信系統(tǒng)的可靠性與實時性。3.提出了基于判決反饋的無邊帶信息改進(jìn)SLM算法,利用判決反饋思想與卷積碼維特比譯碼的誤差傳遞特性,通過對接收信號的對比檢測得到所選加擾序列序號。通過計算機(jī)仿真給出了改進(jìn)SLM算法與傳統(tǒng)SLM算法的性能對比分析,不論是在高斯白噪聲還是突發(fā)噪聲環(huán)境中,改進(jìn)SLM算法的邊帶信息正確率均高于傳統(tǒng)SLM算法,有效地降低了 SLM算法中存在的邊帶信息解讀風(fēng)險,同時提高了系統(tǒng)的通信效率和頻帶利用率,適合通信帶寬資源緊缺的水聲通信。水池實驗中良好的通信效果為仿真分析的結(jié)果提供了有力佐證。
[Abstract]:The characteristics of low carrier frequency, strong multipath interference and high background noise in shallow water acoustic channel make it the most difficult wireless channel to communicate, and the bandwidth available in underwater acoustic communication is very limited. Therefore, it is the focus of underwater acoustic communication researchers to find a communication mode that can resist multipath interference while increasing channel capacity. Multiple-Input-Multiple-Output (Mimo) technology can greatly improve the capacity and frequency band efficiency of communication system without increasing the bandwidth of the system. The OFDM (orthogonal Frequency Division Multiplexing) technology has excellent anti-inter-symbol interference (ISI) capability. In recent years, the scheme of combining the two in underwater acoustic communication has become a new hotspot in underwater acoustic communication. MIMO-OFDM system has the defect of high peak-to-average power ratio (PAPR) because of adopting multicarrier modulation, which not only limits the full utilization of transmission power in the system. Moreover, the requirement of dynamic range of power amplifier is increased, the system cost is increased, and the further development of MIMO-OFDM underwater acoustic communication system is restricted. Therefore, it is very important to suppress the PAPR before the signal enters the amplifier. On the basis of reviewing the existing PAPR suppression techniques in MIMO-OFDM systems, the selective mapping technique is studied in this paper. The main work of this paper is as follows: 1. The feasibility, advantages and disadvantages of different PAPR suppression techniques in underwater acoustic communication are analyzed by simulation, which lays a foundation for the later improved algorithms. 2. Aiming at the disadvantage of SLM peak-to-average ratio (PAPR) suppression technology which needs to transmit sideband information and has a large amount of redundancy, combining with the sparsity of shallow water acoustic channel, two improved SLM algorithms based on channel detection are proposed. Two phase sequence detectors based on time domain interpolation and compression sensing are designed. The core idea of the phase sequence detector used in the improved SLM algorithm is to realize the autonomous recognition of the selected scrambling phase sequences by analyzing and extracting the channel features. The simulation results show that the performance of the two improved SLM algorithms is comparable to that of the SLM algorithm when the sideband information of the receiver is known. The improved algorithm can accurately detect the sequence number of phase sequences when both channel state information and sideband information are unknown, which ensures the reliability and real-time performance of the communication system. An improved SLM algorithm based on decision feedback is proposed in this paper. By using the idea of decision feedback and the error transfer characteristic of convolutional code Viterbi decoding, the sequence number of scrambled sequence is obtained by comparing and detecting the received signal. The performance of the improved SLM algorithm and the traditional SLM algorithm is compared with that of the traditional SLM algorithm by computer simulation. In the environment of Gao Si white noise or burst noise, the improved SLM algorithm has a higher sideband information accuracy than the traditional SLM algorithm. It can effectively reduce the risk of sideband information interpretation in SLM algorithm, improve the communication efficiency and frequency band efficiency of the system, and is suitable for underwater acoustic communication with scarce communication bandwidth. The good communication effect in the tank experiment provides strong evidence for the result of simulation analysis.
【學(xué)位授予單位】：哈爾濱工程大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN929.3

【參考文獻(xiàn)】

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1 喬鋼;王巍;王s，

本文編號：1821620