發(fā)布時(shí)間：2018-06-22 17:56

  本文選題：OFDM-PON + 動(dòng)態(tài)帶寬分配�。� 參考：《南京郵電大學(xué)》2017年碩士論文

【摘要】：隨著PON系統(tǒng)的發(fā)展,正交頻分復(fù)用無(wú)源光網(wǎng)絡(luò)(OFDM-PON)憑借其高效率和靈活多變的優(yōu)勢(shì),成為下一代接入網(wǎng)的主要研究?jī)?nèi)容之一。然而,怎樣在大量的ONU之間有效地分配系統(tǒng)帶寬成為OFDM-PON系統(tǒng)在實(shí)際部署前的重要問(wèn)題之一。首先,本文對(duì)無(wú)源光網(wǎng)絡(luò)的網(wǎng)絡(luò)結(jié)構(gòu)進(jìn)行了介紹,探討了OFDM技術(shù)的基本原理,并且對(duì)OFDM-PON中的相關(guān)關(guān)鍵技術(shù)進(jìn)行了概括分析。其次,本文研究了基于OFDM-PON系統(tǒng)的動(dòng)態(tài)帶寬分配算法,探討了自適應(yīng)調(diào)制算法的發(fā)展歷史和基本原理。在傳統(tǒng)的時(shí)間、波長(zhǎng)和功率的三維動(dòng)態(tài)帶寬分配模型的基礎(chǔ)上,結(jié)合自適應(yīng)調(diào)制技術(shù),提出了一種基于四維動(dòng)態(tài)帶寬分配的自適應(yīng)調(diào)制算法,并且將單個(gè)ONU的傳輸性能進(jìn)行優(yōu)化。其中比特加載算法根據(jù)各ONU比特率需求之比分配各子載波的調(diào)制格式,在子載波數(shù)一定情況下,對(duì)比特率要求高的ONU用更高階的調(diào)制方式來(lái)實(shí)現(xiàn),靈活的分配系統(tǒng)容量。功率加載算法用于根據(jù)各自采用的調(diào)制格式而產(chǎn)生的不同的信噪比,從而為各個(gè)ONU發(fā)射不同的功率。這樣,即使各個(gè)ONU運(yùn)行的比特率不同,也能有平衡的傳輸性能。在長(zhǎng)短距離共存OFDM-PON系統(tǒng)中,由于用戶(hù)之間地理位置的差異性,距離不同帶來(lái)的時(shí)延是不可避免的。本文結(jié)合分組動(dòng)態(tài)帶寬分配(MG-DBA)算法將ONU根據(jù)距離不同進(jìn)行分組,并且結(jié)合自適應(yīng)調(diào)制算法優(yōu)化了長(zhǎng)距離ONU的OSNR,實(shí)現(xiàn)了不同ONU的比特率需求,實(shí)現(xiàn)了長(zhǎng)距離OFDM-PON系統(tǒng)帶寬的動(dòng)態(tài)均衡分配。最后,本文利用OptiSystem 14軟件設(shè)計(jì)了一個(gè)OFDM-PON傳輸系統(tǒng)驗(yàn)證了所提出的帶寬分配模型以及自適應(yīng)算法的可行性。
[Abstract]:With the development of PON system, orthogonal Frequency Division Multiplexing passive Optical Network (OFDM-PON) has become one of the main research contents of next generation access network because of its high efficiency and flexibility. However, how to allocate the bandwidth between a large number of ONUs effectively becomes one of the important problems before the actual deployment of OFDM-PON systems. Firstly, the network structure of passive optical network is introduced, the basic principle of OFDM technology is discussed, and the key technologies in OFDM-PON are analyzed. Secondly, the dynamic bandwidth allocation algorithm based on OFDM-PON system is studied, and the development history and basic principle of adaptive modulation algorithm are discussed. Based on the traditional 3D dynamic bandwidth allocation model of time, wavelength and power, an adaptive modulation algorithm based on four-dimensional dynamic bandwidth allocation is proposed. The transmission performance of a single ONU is optimized. The bit-loading algorithm allocates the modulation format of each subcarrier according to the ratio of each ONU bit rate requirement. In the case of a certain number of sub-carriers, the ONU with high bit rate requirements is implemented in a higher-order modulation mode, and the system capacity is allocated flexibly. The power loading algorithm is used to transmit different power for each ONU according to the different SNR generated by each modulation scheme. Thus, even if the bit rate of each ONU is different, it can achieve balanced transmission performance. In long-distance coexistence OFDM-PON systems, the delay caused by different distances is inevitable due to the difference of geographical location among users. In this paper, we combine packet dynamic bandwidth allocation (MG-DBA) algorithm to group ONU according to different distance, and combine with adaptive modulation algorithm to optimize OSNR of long distance ONU, and realize different bit rate requirement of ONU. The dynamic equalization allocation of long distance OFDM-PON system bandwidth is realized. Finally, an OFDM-PON transmission system is designed using OptiSystem14 software to verify the feasibility of the proposed bandwidth allocation model and adaptive algorithm.
【學(xué)位授予單位】：南京郵電大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TN929.1

【參考文獻(xiàn)】

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本文編號(hào)：2053684