本文選題：多輸入多輸出-正交頻分復(fù)用-電力線通信　切入點(diǎn)：差分空時(shí)碼　出處：《安徽工業(yè)大學(xué)》2017年碩士論文

【摘要】：智能電網(wǎng)因能使電力供應(yīng)達(dá)到節(jié)約能源、降低損耗、增強(qiáng)可靠性而成為業(yè)界研究的熱點(diǎn)。然而,智能電網(wǎng)的諸多功能都有賴于實(shí)時(shí)操作才能付諸實(shí)施,這使得智能電網(wǎng)中各個(gè)終端間快速而可靠的通信成為其成功的重要因素。由于多輸入多輸出電力線通信(MIMO-PLC)可借助原有的電力網(wǎng)基礎(chǔ)設(shè)施實(shí)現(xiàn)電力網(wǎng)絡(luò)全覆蓋的同時(shí),成倍提高系統(tǒng)容量和頻譜利用率,而空時(shí)編碼是實(shí)現(xiàn)MIMO-PLC的關(guān)鍵技術(shù)。為此,本文圍繞多種差分酉空時(shí)碼MIMO-PLC系統(tǒng)方案展開(kāi)研究,并結(jié)合仿真對(duì)比分析這些編碼系統(tǒng)的性能。首先,本文在研究了MIMO-PLC系統(tǒng)傳遞函數(shù)以及噪聲分布模型基礎(chǔ)上,提出了在接收端無(wú)需預(yù)知信道狀態(tài)信息的差分酉空時(shí)碼應(yīng)用于該系統(tǒng)的方案。該方案首先將信息數(shù)據(jù)分別映射到滿足分集積準(zhǔn)則的實(shí)參對(duì)角塊酉矩陣星座上,并以差分方式形成酉空時(shí)碼字;隨后,相應(yīng)碼字經(jīng)數(shù)模轉(zhuǎn)換后,耦合到不同的電力線端口通過(guò)電力線信道發(fā)送出去;最后,收端采用最大似然譯碼得到發(fā)送信息的估計(jì)值。仿真結(jié)果表明:對(duì)于系統(tǒng)數(shù)據(jù)率要求較低的MIMO-PLC系統(tǒng),差分酉空時(shí)碼能夠顯著提高其性能,并且在電力線脈沖噪聲幅值較大時(shí),優(yōu)勢(shì)更加顯著。其次,針對(duì)差分酉空時(shí)碼中滿足分集積準(zhǔn)則的酉矩陣難以構(gòu)造以及數(shù)據(jù)率低的問(wèn)題,提出了將Cayley差分酉空時(shí)碼應(yīng)用于MIMO-PLC系統(tǒng)的方案。該方案首先將攜帶信息的酉矩陣的高度非線性Stiefel流形映射到由斜Hermite矩陣表征的線性空間上,從而可在Cayley變換域和信息理論的基礎(chǔ)上,構(gòu)造出滿足柯西隨機(jī)分布的線性酉矩陣星座。仿真結(jié)果表明:盡管Cayley差分酉空時(shí)碼會(huì)一定程度提高系統(tǒng)誤碼率,但由于其可顯著提高系統(tǒng)的數(shù)據(jù)率,這點(diǎn)對(duì)于數(shù)據(jù)率要求較高的MIMO-PLC系統(tǒng)顯得尤為重要。隨后,針對(duì)MIMO-PLC系統(tǒng)在傳輸高速數(shù)據(jù)時(shí),環(huán)境的多徑使得MIMO信道成為頻率選擇性衰落信道的問(wèn)題,提出了將基于正交空時(shí)分組碼的正交頻分復(fù)用(OFDM)多載波調(diào)制應(yīng)用于寬帶PLC系統(tǒng)的方案。該方案通過(guò)把頻率選擇性信道轉(zhuǎn)化為一個(gè)等價(jià)的多個(gè)平坦衰落子信道構(gòu)成的集合,結(jié)合43?正交空時(shí)分組碼,這樣,用于傳送每個(gè)OFDM分組的每個(gè)載信空時(shí)符號(hào)的子載波可以認(rèn)為在平坦衰落信道內(nèi)傳輸。仿真結(jié)果表明:該編碼系統(tǒng)隨著子載波數(shù)的增加,性能得到顯著提高。最后,為解決矩陣Stiefel流形的非線性導(dǎo)致酉矩陣星座難以構(gòu)造以及信號(hào)集和與費(fèi)用函數(shù)的非凸性問(wèn)題,文章首先提出了將基于特殊李群SP(1)、SU(3)的差分酉空時(shí)碼應(yīng)用于MIMO-OFDM-PLC系統(tǒng)中的方案。以上編碼方案分別通過(guò)放寬可達(dá)到滿分集的不動(dòng)點(diǎn)群的約束條件,在非線性特殊李群中誘導(dǎo)滿足分集積準(zhǔn)則的線形酉矩陣星座。隨后,在忽略SU(3)酉矩陣行列式為1的約束條件下,進(jìn)一步簡(jiǎn)化結(jié)構(gòu)條件構(gòu)建了兩種AB差分酉空時(shí)碼。仿真結(jié)果表明:以上多種編碼方案,可在不犧牲系統(tǒng)性能的前提下,提供更高的數(shù)據(jù)率并獲得較高的分集積;隨子載波數(shù)增加,基于SP(1)的差分酉空時(shí)碼誤碼率顯著降低,而后三種編碼會(huì)有一定程度的提高。
[Abstract]:Because of the smart grid can make power supply to save energy, reduce loss, improve reliability and become the focus of the industry. However, many functions of the smart grid implementation will depend on real-time operation ability, which makes the smart grid in each terminal between the fast and reliable communication has become an important factor in its success. Because of the multiple input multiple output power line communication (MIMO-PLC) by means of power network infrastructure original power network coverage and improve the system capacity and spectrum efficiency exponentially, while the space-time encoding is the key technology to implement MIMO-PLC. Therefore, this paper focuses on several differential unitary space-time code scheme for MIMO-PLC system is studied, and combined with simulation analysis the performance of these encoding system. Firstly, based on the study of the MIMO-PLC system transfer function and noise distribution on the basis of the model, put forward at the receiving end without knowing Program code is applied to the system of channel state information for differential unitary space-time. In this scheme, the information data are mapped to satisfy the argument block diagonal unitary matrix constellation diversity product standards, and the formation of unitary space-time codes in a differential manner; then, the corresponding code word DAC, coupled to the power line different port through the power line channel to send out; finally, the receiver estimates using maximum likelihood decoding by sending information. The simulation results show that the MIMO-PLC system data rate low, DUSTM can significantly improve its performance, and the larger the amplitude of impulse noise in power line, more advantages significant. Secondly, according to the diversity criterion to unitary matrix product structure and the problem of low data rate meet the code in differential unitary space-time, put forward the Cayley difference scheme code used in MIMO-PLC system. The scheme consists of unitary space-time Highly nonlinear manifold mapping Stiefel unitary matrix will first carry information to the linear space of skew Hermite matrix representation, which is based on Cayley transform and information theory, construct the linear unitary matrix constellation Cauchy random distribution. The simulation results show that although Cayley DUSTC will to a certain extent to improve the system BER, but because it can significantly improve the system data rate, which is particularly important for the data rate requirement of MIMO-PLC system is higher. Then, according to the MIMO-PLC system in high speed data transmission, multipath MIMO channel environment makes a frequency selective fading channel, the orthogonal frequency orthogonal space-time block codes based on wavelength division multiplexing (OFDM) multi carrier modulation is applied to broadband PLC system is proposed. The scheme through the frequency selective channel into a plurality of flat an equivalent 琛拌惤瀛愪俊閬撴瀯鎴愮殑闆嗗悎,緇撳悎43?姝ｄ氦絀烘椂鍒嗙粍鐮，

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