本文選題：長期技術(shù)演進 + 正交頻分復(fù)用�。� 參考：《電子科技大學(xué)》2014年碩士論文

【摘要】：LTE技術(shù)是以正交頻分復(fù)用(OFDM)為技術(shù)核心。OFDM是適用于無線環(huán)境下的高速傳輸技術(shù),它具有速率高、抗干擾性強等特點。以O(shè)FDM為核心的LTE技術(shù)體制不僅可以應(yīng)用于民用移動通信,也可以應(yīng)用于各類專網(wǎng),比如集群通信、應(yīng)急通信、軍事專網(wǎng)等。然而,基于OFDM的多載波系統(tǒng)由于多個子載波的疊加造成較大的峰值信號,具有較高的峰均比(PAPR)。這要求系統(tǒng)內(nèi)的模擬器件要有較大的線性區(qū)間,發(fā)送端的功率放大器線性度要求很高,如果采用功率回退會導(dǎo)致功放的效率非常低,在工程上造成系統(tǒng)散熱困難等問題。降低峰均比,是OFDM系統(tǒng)必須要解決的問題,尤其是針對有小型化、低功耗化要求的產(chǎn)品。鑒于上面的情況,本文首先研究了LTE系統(tǒng),從LTE系統(tǒng)下行鏈路的幀結(jié)構(gòu)出發(fā),討論了物理層的信號處理過程,提出了多種仿真場景,分析了LTE系統(tǒng)峰均較高的原因。針對目前多種峰均比抑制技術(shù),比如限幅法、壓縮擴展技術(shù)、選擇映射法、部分傳輸序列法、星座擴展法、編碼法、信號空間擴展技術(shù)、交織限幅法、子載波預(yù)留技術(shù)等等,對各類算法進行了介紹,并分析了各類算法的優(yōu)點和缺點。通過充分比較,結(jié)合LTE下行鏈路峰均比抑制要求,以及在工程上實現(xiàn)的難易程度和代價,研究了峰值脈沖抵消削峰(PC-CFR)算法。將該算法模塊應(yīng)用到LTE系統(tǒng)下行鏈路,采用MATLAB軟件進行仿真,評估其峰均比抑制效果及對系統(tǒng)造成的影響。最后,將該算法在FPGA中實現(xiàn),通過仿真、板級在線測試,驗證其在實際系統(tǒng)的峰均比抑制性能。在LTE下行鏈路中采用PC-CFR峰均比抑制算法,使系統(tǒng)原本15dB的峰均比降低到7dB,并且系統(tǒng)的信噪比損失在可接受的范圍內(nèi)。在實際系統(tǒng)中,使用該算法模塊,大大降低了系統(tǒng)對功率放大器線性度要求,減輕了系統(tǒng)散熱的壓力,降低了產(chǎn)品的體積和功耗。
[Abstract]:LTE technology is based on orthogonal Frequency Division Multiplexing (OFDM). OFDM is a high-speed transmission technology suitable for wireless environment. It has the characteristics of high rate and strong anti-jamming. The LTE system with OFDM as the core can not only be applied to civil mobile communication, but also to all kinds of private networks, such as trunking communication, emergency communication, military private network and so on. However, the multi-carrier system based on OFDM has a high PAPR because of the large peak signal caused by the superposition of multiple sub-carriers. This requires the analog devices in the system to have a large linear range, and the linearity of the power amplifier at the transmitter is very high. If the power retrogression is adopted, the efficiency of the power amplifier will be very low and the system heat dissipation will be difficult in engineering. Reducing PAPR is a problem that must be solved in OFDM systems, especially for products with miniaturization and low power consumption. In view of the above situation, this paper first studies the LTE system. Based on the frame structure of the downlink of the LTE system, the signal processing process of the physical layer is discussed, and various simulation scenarios are proposed, and the reasons for the high peak of the LTE system are analyzed. Aiming at various PAPR suppression techniques, such as limiting, compression and expansion, selective mapping, partial transmission sequence, constellation expansion, coding, signal spatial expansion, interleaving and limiting, subcarrier reservation, etc. Various algorithms are introduced and their advantages and disadvantages are analyzed. In this paper, the peak pulse cancellation (PC-CFR) algorithm is studied by comparing the PAPR suppression requirements of LTE downlink, as well as the difficulty and cost of engineering implementation. The algorithm module is applied to the downlink of LTE system. MATLAB software is used to simulate the algorithm to evaluate the PAPR suppression effect and its impact on the system. Finally, the algorithm is implemented in FPGA, and its PAPR suppression performance is verified by simulation and on-line testing at board level. PC-CFR suppression algorithm is used in LTE downlink to reduce the PAPR of 15 dB to 7 dB, and the SNR loss of the system is within an acceptable range. In the practical system, the algorithm module can greatly reduce the linearity of the power amplifier, reduce the pressure of the system heat dissipation, and reduce the volume and power consumption of the product.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN929.5

【參考文獻】

相關(guān)碩士學(xué)位論文 前1條

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本文編號：2105553