【摘要】：為滿足用戶不斷增長的定位需求,3GP PLTE制定了新的定位協(xié)議,對定位提供了全面支持,無線定位將在LTE時代的民用和軍用領域內發(fā)揮重要的實用價值。但目前LTE定位技術未充分利用MIMO和OFDM技術為其提供的優(yōu)勢,存在以下三個方面的問題：1)傳統(tǒng)的時延估計算法在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。針對上述問題,本課題依托軍隊某重點項目,對LTE系統(tǒng)的定位技術展開研究。首先,根據(jù)LTE系統(tǒng)OFDM信號的時、頻特性提出一種分組聯(lián)合時延估計算法；然后,在估計時延的基礎上,提出一種改進的Mean-OTDOA定位算法減小遠近效應對定位精度的影響；最后,針對實際NLOS場景,根據(jù)LTE系統(tǒng)豐富的空、時、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信號特性的分組聯(lián)合時延估計算法。首先,根據(jù)OFDM信號的時頻特性提出一種基于頻域相偏的多徑時延估計模型。在此基礎上,結合LTE系統(tǒng)的實際特點提出一種分組聯(lián)合時延估計算法一-GJ-TDE算法。該算法首先將OFDM系統(tǒng)的時域接收信號轉換為頻域信號,然后對頻域信號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)矩陣組分級估計時延；最后,取各時延估計值的平均作為定位時延值。仿真結果表明：在SNR為0dB、抽樣間隔為8的條件下,GJ-TDE算法的RMSE比基于時域同步的Mensing算法降低了5.5034m。2、提出一種改進的Mean-OTDOA定位算法。在得到終端與各基站的時延估計值的基礎上,計算出終端與參與定位的各基站的距離測量值并對終端與各基站的距離測量值進行平均,作為OTDOA定位方法中的參考距離；然后,利用Taylor級數(shù)展開法對終端位置進行估計。仿真結果表明：在基站數(shù)目為5、測量誤差的標準差為50m時,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、頻聯(lián)合信息的NLOS鑒別方法。首先,推導出線性抽頭延遲線信道模型的頻域信道響應的歸一化互相關函數(shù)；然后,構造出在LOS和NLOS情況下具有不同分布特點的STFSCD(空時頻相關差之和)參數(shù),并根據(jù)STFSCD的大小鑒別NLOS。仿真結果表明：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STFSCD參數(shù)的判決門限為3時,NLOS的正確檢測概率為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.
【學位授予單位】：解放軍信息工程大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.5

【參考文獻】

相關期刊論文 前3條

1 唐科萍;許方恒;沈才j;;基于位置服務的研究綜述[J];計算機應用研究;2012年12期

2 程龍;吳成東;張云洲;賈子熙;;基于假設檢驗的NLOS確定及最小殘差定位算法[J];東北大學學報(自然科學版);2012年07期

3 常戎;呂善偉;;適用于NLOS傳播環(huán)境的幾何定位方法[J];電子與信息學報;2007年09期

相關博士學位論文 前2條

1 張光榮;LTE系統(tǒng)的小區(qū)間干擾協(xié)調技術研究[D];中國科學技術大學;2012年

2 楊天池;單站定位的散射信息幾何構造法[D];解放軍信息工程大學;2009年

相關碩士學位論文 前3條

1 趙衛(wèi)波;面向LTE終端定位的時延估計算法研究[D];解放軍信息工程大學;2013年

2 陳健;面向3GPP-LTE終端無線定位的參數(shù)估計與定位解算研究[D];電子科技大學;2011年

3 楊琳琳;空間譜估計算法研究[D];華中科技大學;2007年

，

本文編號：2206224