【摘要】：同步錯(cuò)誤,包括符號(hào)的插入與刪節(jié),存在于各類通信與存儲(chǔ)系統(tǒng)中,如無(wú)線光通信中的差分脈沖位置調(diào)制(Differential Pulse-Position Modulation,DPPM)系統(tǒng)、比特圖形化介質(zhì)(Bit Patterned Media,BPM)存儲(chǔ)系統(tǒng)等。研究者們?cè)O(shè)計(jì)了各種可糾正同步錯(cuò)誤的糾錯(cuò)碼方案,其中一種為基于擴(kuò)展網(wǎng)格圖的卷積碼方案,該方案可同時(shí)糾正卷積碼接收序列中的插入、刪節(jié)和替代錯(cuò)誤�；诖�,本文面向DPPM系統(tǒng)中的同步錯(cuò)誤,研究基于擴(kuò)展網(wǎng)格圖的卷積碼處理方案。針對(duì)DPPM中同步錯(cuò)誤的具體特點(diǎn),本文設(shè)計(jì)了一種迭代檢測(cè)譯碼方案。該方案以DPPM符號(hào)序列的軟判決檢測(cè)算法和糾正同步錯(cuò)誤的卷積碼譯碼方案為基礎(chǔ),利用不同的DPPM符號(hào)調(diào)制后的碼片長(zhǎng)度不等這一特點(diǎn),將譯碼后再重新編碼調(diào)制得到的碼片長(zhǎng)度和迭代次數(shù)作為判決條件,在軟判決檢測(cè)和基于刪剪網(wǎng)格圖的維特比譯碼器之間進(jìn)行迭代。仿真結(jié)果表明,與未迭代系統(tǒng)相比,該方案可有效降低誤幀率,獲得較大的性能增益。進(jìn)一步,為改善DPPM系統(tǒng)中卷積碼編譯碼方案的糾錯(cuò)性能,本文將Reed-Solomon(RS)碼級(jí)聯(lián)卷積碼方案應(yīng)用到DPPM系統(tǒng)中。該方案采用卷積碼作為內(nèi)碼糾正部分同步錯(cuò)誤和替代錯(cuò)誤,利用RS碼作為外碼糾正由于信道和內(nèi)碼誤同步造成的突發(fā)性替代錯(cuò)誤。仿真結(jié)果表明,該方案可有效糾正DPPM系統(tǒng)中插入、刪節(jié)和替代錯(cuò)誤。綜上所述,本文針對(duì)DPPM系統(tǒng)中的同步問(wèn)題,提出了一種迭代檢測(cè)譯碼算法,并將RS碼級(jí)聯(lián)卷積碼的方案應(yīng)用至DPPM系統(tǒng)中。
[Abstract]:Synchronous errors, including the insertion and deletion of symbols, are present in various communication and storage systems, such as differential pulse position modulation (Differential Pulse-Position Modulation,DPPM) systems in wireless optical communications, bitwise graphical media (Bit Patterned Media, BPM) storage system, etc. Researchers have designed a variety of error-correcting schemes to correct synchronous errors, one of which is an extended trellis graph based convolutional code scheme, which can correct the insertion, deletion and substitution errors in the receiving sequence of the convolutional code at the same time. Based on this, this paper studies the convolutional code processing scheme based on extended trellis graph for synchronization errors in DPPM system. According to the characteristics of synchronous errors in DPPM, this paper designs an iterative detection decoding scheme. This scheme is based on the soft decision detection algorithm of DPPM symbol sequence and the convolutional code decoding scheme which corrects synchronous errors. It makes use of the different length of the code chip modulated by different DPPM symbols. The length and the number of iterations obtained from the decoding and re-coding modulation are taken as the decision conditions, and iterations are carried out between the soft-decision detection and the Viterbi decoder based on truncated trellis graph. The simulation results show that the proposed scheme can effectively reduce the frame error rate and obtain a large performance gain compared with the non-iterative system. Furthermore, in order to improve the error correction performance of convolutional code encoding and decoding scheme in DPPM system, the concatenated convolutional code scheme of Reed-Solomon (RS) code is applied to DPPM system in this paper. In this scheme, convolutional codes are used as internal codes to correct partial synchronization errors and substitution errors, and RS codes are used as outer codes to correct sudden substitution errors caused by channel and internal code error synchronization. The simulation results show that the scheme can effectively correct the insertion, deletion and substitution errors in DPPM system. To sum up, this paper proposes an iterative detection and decoding algorithm for synchronization in DPPM systems, and applies the scheme of concatenated convolutional codes of RS codes to DPPM systems.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN911.22

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 張譯方;陳為剛;;糾正DPPM中插入刪節(jié)錯(cuò)誤的糾錯(cuò)碼方案[J];信息技術(shù);2014年08期

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本文編號(hào)：2329573