BIAWGN信道下的擴(kuò)展窗噴泉碼設(shè)計研究
發(fā)布時間：2019-01-10 12:56
【摘要】：隨著無線通訊技術(shù)的迅猛發(fā)展和網(wǎng)絡(luò)帶寬的不斷提高,多媒體傳輸正日漸成為通信行業(yè)的主干業(yè)務(wù)。然而,在實際通信過程中,高丟包率以及信道的非理想性等嚴(yán)重降低了信息傳輸?shù)目煽啃�。�?shù)字噴泉碼(Digital Fountain Codes )作為一種新的前向糾錯編碼(Forward Error Correction, FEC)技術(shù),不同于具有固定碼率的傳統(tǒng)的糾錯方案,其憑借無碼率,無需反饋重傳,編譯碼復(fù)雜度低等優(yōu)點,在惡劣的信道中都能保證數(shù)據(jù)的高質(zhì)量傳輸,因此成為了編碼界的研究熱點。針對多媒體應(yīng)用中重要等級不同的數(shù)據(jù)需要不等水平保護(hù)的情景,本論文以具有不等差錯保護(hù)(Unequal Error Protection, UEP )特性的擴(kuò)展窗噴泉(Expanding Window Fountain, EWF)碼的編碼和調(diào)制算法為研究核心,提出了一種新穎的可適用于BIAWGN信道的UEP噴泉碼�；舅枷胧�:EWF碼的錯誤平層主要是由度值很小的輸入節(jié)點影響的,為了改善其性能,將EWF碼編碼過程進(jìn)行了修改,最終使輸入符號度值由泊松分布變成了具有兩到三個度值的均勻分布。此外,由于EWF碼的不同窗輸出的符號經(jīng)過編碼之后具有不同的重要等級,因此可以加入不等功率分配(Unequal Power Allocation, UPA),進(jìn)一步改善EWF碼的UEP性能。為了驗證提出方案的漸進(jìn)性能,本文推導(dǎo)出了完整的外部信息轉(zhuǎn)移(Extrinsic Information Transfer,EXIT)函數(shù)漸進(jìn)分析公式,從漸進(jìn)分析和實際仿真兩個角度驗證了規(guī)則的度分布可以很好的降低EWF碼的錯誤平層,加入不等功率分配,在很大程度上進(jìn)一步改善了更高等級比特的性能�；赗aptor碼的思想,為了進(jìn)一步消除錯誤平層,本文將高碼率的LDPC碼與新提出的EWF碼結(jié)合構(gòu)建了一種新的預(yù)編碼EWF碼。漸進(jìn)分析和仿真結(jié)果顯示,與傳統(tǒng)預(yù)編碼EWF碼相比,本文新提出的EWF碼譯碼性能有明顯改善,并且具有更大靈活性。此外,通過聯(lián)合優(yōu)化新提出的預(yù)編碼EWF碼的編碼參數(shù)和功率分配比例系數(shù),可以使譯碼性能達(dá)到最佳。
[Abstract]:With the rapid development of wireless communication technology and the continuous improvement of network bandwidth, multimedia transmission is becoming the backbone of the communication industry. However, in the actual communication process, the high packet loss rate and channel non-ideal seriously reduce the reliability of information transmission. Digital fountain code (Digital Fountain Codes), as a new forward error correction coding (Forward Error Correction, FEC) technique, is different from the traditional error correction scheme with fixed bit rate. It has the advantages of no code rate, no need of feedback retransmission, and low coding and decoding complexity. In bad channels, high quality data transmission can be guaranteed, so it has become a research hotspot in coding field. In view of the situation that different important levels of data need unequal level protection in multimedia applications, this paper uses the extended window fountain (Expanding Window Fountain, with unequal error protection (Unequal Error Protection, UEP) characteristics. Based on the coding and modulation algorithms of EWF codes, a novel UEP fountain code for BIAWGN channels is proposed. The basic idea is: the error level of EWF code is mainly affected by the input node with very small degree. In order to improve its performance, the coding process of EWF code is modified. Finally, the input symbolic degree value is changed from Poisson distribution to uniform distribution with two to three degrees. In addition, because the symbols output from different windows of EWF codes have different important grades after encoding, (Unequal Power Allocation, UPA), with unequal power distribution can be added to further improve the UEP performance of EWF codes. In order to verify the asymptotic performance of the proposed scheme, a complete asymptotic analysis formula of the external information transfer (Extrinsic Information Transfer,EXIT) function is derived in this paper. From the point of view of asymptotic analysis and actual simulation, it is proved that the regular degree distribution can reduce the error level layer of EWF code and add unequal power allocation to further improve the performance of higher level bits. Based on the idea of Raptor code, in order to further eliminate the error level, this paper combines the high bit-rate LDPC code with the newly proposed EWF code to construct a new pre-coded EWF code. The asymptotic analysis and simulation results show that compared with the traditional precoded EWF codes, the new EWF codes proposed in this paper have better decoding performance and more flexibility. In addition, the decoding performance can be optimized by jointly optimizing the coding parameters and the power allocation ratio coefficients of the proposed precoded EWF codes.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN911.22
本文編號：2406340
[Abstract]:With the rapid development of wireless communication technology and the continuous improvement of network bandwidth, multimedia transmission is becoming the backbone of the communication industry. However, in the actual communication process, the high packet loss rate and channel non-ideal seriously reduce the reliability of information transmission. Digital fountain code (Digital Fountain Codes), as a new forward error correction coding (Forward Error Correction, FEC) technique, is different from the traditional error correction scheme with fixed bit rate. It has the advantages of no code rate, no need of feedback retransmission, and low coding and decoding complexity. In bad channels, high quality data transmission can be guaranteed, so it has become a research hotspot in coding field. In view of the situation that different important levels of data need unequal level protection in multimedia applications, this paper uses the extended window fountain (Expanding Window Fountain, with unequal error protection (Unequal Error Protection, UEP) characteristics. Based on the coding and modulation algorithms of EWF codes, a novel UEP fountain code for BIAWGN channels is proposed. The basic idea is: the error level of EWF code is mainly affected by the input node with very small degree. In order to improve its performance, the coding process of EWF code is modified. Finally, the input symbolic degree value is changed from Poisson distribution to uniform distribution with two to three degrees. In addition, because the symbols output from different windows of EWF codes have different important grades after encoding, (Unequal Power Allocation, UPA), with unequal power distribution can be added to further improve the UEP performance of EWF codes. In order to verify the asymptotic performance of the proposed scheme, a complete asymptotic analysis formula of the external information transfer (Extrinsic Information Transfer,EXIT) function is derived in this paper. From the point of view of asymptotic analysis and actual simulation, it is proved that the regular degree distribution can reduce the error level layer of EWF code and add unequal power allocation to further improve the performance of higher level bits. Based on the idea of Raptor code, in order to further eliminate the error level, this paper combines the high bit-rate LDPC code with the newly proposed EWF code to construct a new pre-coded EWF code. The asymptotic analysis and simulation results show that compared with the traditional precoded EWF codes, the new EWF codes proposed in this paper have better decoding performance and more flexibility. In addition, the decoding performance can be optimized by jointly optimizing the coding parameters and the power allocation ratio coefficients of the proposed precoded EWF codes.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN911.22
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