面向LTE系統(tǒng)的終端定位算法研究
發(fā)布時(shí)間：2018-08-26 21:33
【摘要】：為滿足用戶不斷增長(zhǎng)的定位需求,3GP PLTE制定了新的定位協(xié)議,對(duì)定位提供了全面支持,無(wú)線定位將在LTE時(shí)代的民用和軍用領(lǐng)域內(nèi)發(fā)揮重要的實(shí)用價(jià)值。但目前LTE定位技術(shù)未充分利用MIMO和OFDM技術(shù)為其提供的優(yōu)勢(shì),存在以下三個(gè)方面的問(wèn)題：1)傳統(tǒng)的時(shí)延估計(jì)算法在LTE系統(tǒng)中性能受限；2)LTE協(xié)議中OTDOA定位算法魯棒性較差；3)傳統(tǒng)的NLOS誤差鑒別方法在LTE系統(tǒng)中鑒別精度低。針對(duì)上述問(wèn)題,本課題依托軍隊(duì)某重點(diǎn)項(xiàng)目,對(duì)LTE系統(tǒng)的定位技術(shù)展開研究。首先,根據(jù)LTE系統(tǒng)OFDM信號(hào)的時(shí)、頻特性提出一種分組聯(lián)合時(shí)延估計(jì)算法；然后,在估計(jì)時(shí)延的基礎(chǔ)上,提出一種改進(jìn)的Mean-OTDOA定位算法減小遠(yuǎn)近效應(yīng)對(duì)定位精度的影響；最后,針對(duì)實(shí)際NLOS場(chǎng)景,根據(jù)LTE系統(tǒng)豐富的空、時(shí)、頻信息提出一種NLOS鑒別的方法。具體研究工作如下：1、提出一種基于OFDM信號(hào)特性的分組聯(lián)合時(shí)延估計(jì)算法。首先,根據(jù)OFDM信號(hào)的時(shí)頻特性提出一種基于頻域相偏的多徑時(shí)延估計(jì)模型。在此基礎(chǔ)上,結(jié)合LTE系統(tǒng)的實(shí)際特點(diǎn)提出一種分組聯(lián)合時(shí)延估計(jì)算法一-GJ-TDE算法。該算法首先將OFDM系統(tǒng)的時(shí)域接收信號(hào)轉(zhuǎn)換為頻域信號(hào),然后對(duì)頻域信號(hào)抽樣分成多組低維的接收數(shù)據(jù)矩陣,并利用各抽樣數(shù)據(jù)矩陣組分級(jí)估計(jì)時(shí)延；最后,取各時(shí)延估計(jì)值的平均作為定位時(shí)延值。仿真結(jié)果表明：在SNR為0dB、抽樣間隔為8的條件下,GJ-TDE算法的RMSE比基于時(shí)域同步的Mensing算法降低了5.5034m。2、提出一種改進(jìn)的Mean-OTDOA定位算法。在得到終端與各基站的時(shí)延估計(jì)值的基礎(chǔ)上,計(jì)算出終端與參與定位的各基站的距離測(cè)量值并對(duì)終端與各基站的距離測(cè)量值進(jìn)行平均,作為OTDOA定位方法中的參考距離；然后,利用Taylor級(jí)數(shù)展開法對(duì)終端位置進(jìn)行估計(jì)。仿真結(jié)果表明：在基站數(shù)目為5、測(cè)量誤差的標(biāo)準(zhǔn)差為50m時(shí),Mean-OTDOA算法的RMSE比OTDOA算法降低了5.2039m,從而提高了終端定位精度。3、提出一種基于空、時(shí)、頻聯(lián)合信息的NLOS鑒別方法。首先,推導(dǎo)出線性抽頭延遲線信道模型的頻域信道響應(yīng)的歸一化互相關(guān)函數(shù)；然后,構(gòu)造出在LOS和NLOS情況下具有不同分布特點(diǎn)的STFSCD(空時(shí)頻相關(guān)差之和)參數(shù),并根據(jù)STFSCD的大小鑒別NLOS。仿真結(jié)果表明：在LTE系統(tǒng)的EPA信道模型中,利用STFSCD參數(shù)可鑒別出NLOS,且當(dāng)STFSCD參數(shù)的判決門限為3時(shí),NLOS的正確檢測(cè)概率為96.88%,虛警概率為3.6%。
[Abstract]:A new positioning protocol has been developed to meet the increasing needs of users. It provides a comprehensive support for positioning. Wireless positioning will play an important role in the civil and military fields in the LTE era. However, the current LTE localization technology does not make full use of the advantages provided by MIMO and OFDM technology, and there are three problems in the following three aspects: 1) the traditional time delay estimation algorithm has poor robustness in the LTE system with limited performance / 2) OTDOA location algorithm in the LTE protocol; 3) the traditional NLOS error discriminant method has low accuracy in LTE system. In order to solve the above problems, this paper studies the positioning technology of LTE system based on a key military project. First of all, according to the time and frequency characteristics of OFDM signal in LTE system, a packet joint time delay estimation algorithm is proposed. Then, based on the estimation of time delay, an improved Mean-OTDOA localization algorithm is proposed to reduce the influence of near-far effect on location accuracy. According to the rich space, time and frequency information of LTE system, a method of NLOS discrimination is proposed for the actual NLOS scene. The main research work is as follows: 1. A packet joint time delay estimation algorithm based on the characteristics of OFDM signal is proposed. Firstly, according to the time-frequency characteristic of OFDM signal, a multipath time delay estimation model based on frequency domain phase offset is proposed. On this basis, combined with the practical characteristics of LTE system, a combined packet time delay estimation algorithm--GJ-TDE algorithm is proposed. The algorithm first converts the received signals in time domain of OFDM system into frequency-domain signals, then the signals in frequency domain are sampled into groups of low-dimensional received data matrices, and the time delay is estimated by using each set of sampling data matrices at different levels. The average of each time delay estimate is taken as the location delay value. The simulation results show that the RMSE of the GJ-TDE algorithm is 5.5034m.2less than that of the Mensing algorithm based on time-domain synchronization under the condition that the SNR is 0 dB and the sampling interval is 8. An improved Mean-OTDOA localization algorithm is proposed. Based on the time delay estimation of the terminal and each base station, the distance measurement value between the terminal and the base station participating in the positioning is calculated, and the distance measurement value between the terminal and the base station is averaged, which can be used as the reference distance in the OTDOA positioning method. The terminal position is estimated by Taylor series expansion method. The simulation results show that the RMSE of Mean-OTDOA algorithm is 5.2039mless than that of OTDOA algorithm when the number of base stations is 5 and the standard deviation of measurement error is 50m. The accuracy of terminal location is improved by 0.3.A NLOS discrimination method based on space-time and time-frequency joint information is proposed. First, the normalized cross-correlation function of the frequency domain channel response of the linear tap delay line channel model is derived, and then the STFSCD (sum of space-time-frequency correlation difference) parameters with different distribution characteristics are constructed in the case of LOS and NLOS. The NLOS. is identified according to the size of STFSCD. The simulation results show that in the EPA channel model of LTE system, the NLOS, can be identified by using the STFSCD parameter. The correct detection probability of STFSCD parameter is 96.88 and the false alarm probability is 3.6 when the decision threshold of STFSCD parameter is 3.
【學(xué)位授予單位】：解放軍信息工程大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN929.5
本文編號(hào)：2206224
[Abstract]:A new positioning protocol has been developed to meet the increasing needs of users. It provides a comprehensive support for positioning. Wireless positioning will play an important role in the civil and military fields in the LTE era. However, the current LTE localization technology does not make full use of the advantages provided by MIMO and OFDM technology, and there are three problems in the following three aspects: 1) the traditional time delay estimation algorithm has poor robustness in the LTE system with limited performance / 2) OTDOA location algorithm in the LTE protocol; 3) the traditional NLOS error discriminant method has low accuracy in LTE system. In order to solve the above problems, this paper studies the positioning technology of LTE system based on a key military project. First of all, according to the time and frequency characteristics of OFDM signal in LTE system, a packet joint time delay estimation algorithm is proposed. Then, based on the estimation of time delay, an improved Mean-OTDOA localization algorithm is proposed to reduce the influence of near-far effect on location accuracy. According to the rich space, time and frequency information of LTE system, a method of NLOS discrimination is proposed for the actual NLOS scene. The main research work is as follows: 1. A packet joint time delay estimation algorithm based on the characteristics of OFDM signal is proposed. Firstly, according to the time-frequency characteristic of OFDM signal, a multipath time delay estimation model based on frequency domain phase offset is proposed. On this basis, combined with the practical characteristics of LTE system, a combined packet time delay estimation algorithm--GJ-TDE algorithm is proposed. The algorithm first converts the received signals in time domain of OFDM system into frequency-domain signals, then the signals in frequency domain are sampled into groups of low-dimensional received data matrices, and the time delay is estimated by using each set of sampling data matrices at different levels. The average of each time delay estimate is taken as the location delay value. The simulation results show that the RMSE of the GJ-TDE algorithm is 5.5034m.2less than that of the Mensing algorithm based on time-domain synchronization under the condition that the SNR is 0 dB and the sampling interval is 8. An improved Mean-OTDOA localization algorithm is proposed. Based on the time delay estimation of the terminal and each base station, the distance measurement value between the terminal and the base station participating in the positioning is calculated, and the distance measurement value between the terminal and the base station is averaged, which can be used as the reference distance in the OTDOA positioning method. The terminal position is estimated by Taylor series expansion method. The simulation results show that the RMSE of Mean-OTDOA algorithm is 5.2039mless than that of OTDOA algorithm when the number of base stations is 5 and the standard deviation of measurement error is 50m. The accuracy of terminal location is improved by 0.3.A NLOS discrimination method based on space-time and time-frequency joint information is proposed. First, the normalized cross-correlation function of the frequency domain channel response of the linear tap delay line channel model is derived, and then the STFSCD (sum of space-time-frequency correlation difference) parameters with different distribution characteristics are constructed in the case of LOS and NLOS. The NLOS. is identified according to the size of STFSCD. The simulation results show that in the EPA channel model of LTE system, the NLOS, can be identified by using the STFSCD parameter. The correct detection probability of STFSCD parameter is 96.88 and the false alarm probability is 3.6 when the decision threshold of STFSCD parameter is 3.
【學(xué)位授予單位】：解放軍信息工程大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN929.5
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