High Performance Compressed Sampling for OFDM-UWB Systems

In order to solve the problem of high-speed sampling in OFDM based ultra wide band(UWB) systems, this paper first gives analysis on the applicability of existing compressed sampling methods. Then, on the basis of an established segmented observation model, it presents an optimized parallel segmented compressed sampling(OPSCS) scheme based on Hadamard matrix. The orthogonal Hadamard matrix is adopted to construct the segmented measurement matrix with any dimensions, thus orthogonal or quasi-orthogonal multiplex observation sequences are obtained, and the restricted isometry property is improved. The optimized orthogonal matching pursuit algorithm is also used for the known sparsity avoiding iterative operation. Researches show that the proposed method can effectively reduce the sampling rate in OFDM-UWB systems, and also has a good ability of noise resisting that it achieves a high system performance better than the existing schemes of compressed sampling and even Nyquist rate sampling.

Optimal transmissions for space-time coded OFDM UWB systems

The emerging ultra-wideband (UWB) system offers a great potential for the design of high-speed short-range communications.Compared with great progress at physical layer,the corresponding medium access control (MAC) layer designs are naturally placed on the schedules.We focus on the optimal power load scheme,which is an integral part of the MAC layer protocol design,for UWB space-time coded (STC) orthogonal frequency-division multiplexing (OFDM) transmissions.Assumed the transmitter has perfect or partial channel stage information (CSI).Based on the optimization criteria of maximizing capacity,three kinds of power load schemes were presented with different tradeoff among performance,complexity and feedback bandwidth overhead.The proposed schemes are verified and compared under the channel prototype proposed by IEEE 802.15.3a Task Group.

On UWB system performance under impulsive noise environment

In this paper, the performance of UWB (ultrawide bandwidth) radio systems under impulsive noise environment (IN-E) is investigated. At first, the Middleton's class a model is used as a model of impulsive noise (IN), we investigate the statistical characteristics of in-phase and quadrature components of IN, and it is proved that unlike Gaussian noise (GN), they are dependent especially to IN with small impulsive indices, Then, making use of this dependence between in-phase and quadrature components, an ovel UWB radio receiver designed for IN is proposed. The exact expression for the average BER (bit error rate) of this receiver, which is a function of SNR (signal to noise power ratio) and threshold value, is derived. Thirdly, we'll discuss the optimum threshold value. We'll also estimate the performance of UWB radio systems with the proposed receiver designed for IN and with the conventional receiver designed for GN in INE. Numerical results show that the performance achieved by the proposed UWB radio receiver is much etter than that of the conventional UWB radio receiver. Meanwhile, it is shown that both impulsive index and threshold value have much effect on the performance of UWB radio systems under the condition of INE.

A THROUGHPUT-EFFICIENT ADAPTIVE TRANSMIT-RECEIVE SCHEME FOR INDOOR DS-UWB SYSTEMS

In this paper, a novel adaptive transmit-receive scheme is presented for indoor Direct Se- quence Ultra-WideBand (DS-UWB) systems. In the proposed scheme, a simple switch module is in- troduced to improve the system throughput. Furthermore, adaptive detection is implemented via an improved Least Mean Squares (LMS) algorithm. The convergence behavior and the Bit Error Rate (BER) performance of the proposed scheme are examined under the realistic channel models. Simu- lation results show that, nearly without loss of the BER performance, the proposed scheme can obtain at least 2/3 improvement in training overhead compared with the conventional approach.

A NEW SYNCHRONIZATION SCHEME USING PERFECT PUNCTURED BINARY SEQUENCE PAIRS IN DS-UWB SYSTEM

Ultra WideBand (UWB) radio is a new wireless technology that transmits extremely short duration radio impulses. In this paper, a new synchronization scheme is proposed in Direct Sequence (DS) UWB system using Perfect Punctured Binary Sequence Pairs (PPBSP) as the preamble. It can acquire both Pseudo-Noise (PN) sequence and frame synchronization at the same time. The properties and the combinatorial admis sibility conditions of PPBSP are presented. The simulation results show that PPBSP is good for synchronization by their good cross-correlation properties both under Additive White Gaussian Noise (AWGN) channel and modified Saleh-Valenzuela channel.

A Modified Code Domain Transmitted Reference UWB System

Based on the research on time domain and frequency domain transmitted reference Impulse Radio Ultra-WideBand (IR-UWB) system, this paper studies the optimization design for code domain transmitted reference IR-UWB system, and proposes a modified code domain transmitted reference IR-UWB system. The Bit Error Rate (BER) expressions for the modified system model in the condition of Additive White Gaussian Noise (AWGN) and multipath fading are deduced respectively. In addition, the performances of the modified system and the other three transmitted reference IR-UWB systems are simulated and compared. Theoretical analysis and simulation results show that the performance of the modified system is superior to the other three systems.

P×N IFFT FOR OFDM-BASED UWB SYSTEM

In this letter,P × N-pointIFFT is proposed to replace the N-point IFFT and analog fre-quency conversion in an Orthogonal Frequency Division Multiplexing (OFDM)-based Ultra-WideBand (UWB) system,and a new algorithm,named fast P × N-pointIFFT,is designed to reduce the com-plexity of the P × N-pointIFFT in the proposed scheme.

Feasibility Study of 60 GHz UWB System for Gigabit M2M Communications

In this paper,the feasibility and performance of millimeter wave(mm Wave)60 GHz ultra-wide band(UWB)systems for gigabit machine-to-machine(M2M)communications are analyzed.Specifically,based on specifications,channel measurements and models for both line-of-sight(LOS)and non-LOS(NLOS)scenarios,60 GHz propagation mechanisms are summarized,and 60 GHz UWB link budget and performance are analyzed.Tests are performed for determining ranges and antenna configurations.Results show that gigabit capacity can be achieved with omni-directional antennas configuration at the transceiver,especially in LOS conditions.When the LOS path is blocked by a moving person or by radiowave propagation in the NLOS situation,omni-directional and directional antennas configuration at the transceiver is required,especially for a larger range between machines in office rooms.Therefore,it is essential to keep a clear LOS path in M2M applications like gigabit data transfer.The goal of this work is to provide useful information for standardizations and design of 60 GHz UWB systems.

FIXED-POINT BLIND ADAPTIVE MULTIUSER DETECTION ALGORITHM FOR IR UWB SYSTEMS IN MULTIPATH CHANNEL

Using the hypothesis that data transmitted by different users are statistically independent of each other,this paper proposes a fixed-point blind adaptive multiuser detection algorithm for Time-Hopping (TH) Impulse Radio (IR) Ultra Wide Band (UWB) systems in multipath channel,which is based on Independent Component Analysis (ICA) idea. The proposed algorithm employs maximizing negentropy criterion to separate the data packets of different users. Then the user characteristic se-quences are utilized to identify the data packet order of the desired user. This algorithm only needs the desired user’s characteristic sequence instead of channel information,power information and time-hoping code of any user. Due to using hypothesis of statistical independence among users,the proposed algorithm has the outstanding Bit Error Rate (BER) performance and the excellent ability of near-far resistance. Simulation results demonstrate that this algorithm has the performance close to that of Maximum-Likelihood (ML) algorithm and is a suboptimum blind adaptive multiuser detection algorithm of excellent near-far resistance and low complexity.

UWB System Based on the Modified Gegenbauer Function in MISO Channel

In this paper, we propose a new multi-user Rake receiver, based on the interference mutualization with a matrix representation for Multiple Input Single Output MISO channel. The proposed system used the Modified Gegenbauer functions in order to generate the signal and to ensure the multi users transmission system. The new proposed receiver allows, using the temporal and special diversity, to avoid the interferences between symbols and to improve the system performances in terms of Bit Error Rate BER and interferences between users with a low algorithm complexity. The proposed solution is based on the classical Rake receiver associated with the equalizer receiver. In order to adapt the Rake approach, in single detection case and in multi users Ultra Wide Band environment, we propose a multi-user Rake receiver using the matrix form. Our proposed system is evaluated in terms of channel effects and multi users’ interferences.

基于改进SHKF算法的UWB/IMU组合定位方法

针对复杂环境下超宽带(UWB)无线定位系统存在非视距(NLOS)及随机误差的问题,提出一种基于改进Sage-Husa卡尔曼滤波算法(SHKF)的UWB/IMU组合定位方法。首先,设计了一种基于概率密度的提升树,将UWB/IMU特征数据的概率分布密度引入提升树的损失函数中,鉴别出NLOS信号;然后,设计了一种改进SHKF算法,根据新息变化趋势定义自适应因子,实时调整对新息误差修正的策略以调节历史噪声对当前定位的影响,进而提升UWB/IMU组合定位的稳定性和精度。实验结果表明,所提方法将NLOS信号鉴别精度提升至99.12%,定位均方根误差降低至4.30 cm,提升了复杂环境下UWB/IMU组合系统定位精度。

基于UWB技术的高精度定位系统设计

为了解决传统定位技术的不足,设计了UWB高精度定位系统。定位系统主要包括了电子移动标签系统、UWB天线标签系统等通信接口电路系统的软硬件设计。硬件设计主要包括主控DWM-1000芯片、DWM-1000基站天线芯片和无线通信接口等电路,软件系统主要包括了基本软件逻辑和电子便签P坐标解析算法软件流程设计,系统实现了电磁波信号发送、接收、数据计算分析和精确定位。测试结果表明,系统定位误差范围均小于10 cm,降低了非视距误差和噪声干扰影响,满足了定位系统高精度、强稳定性和低功耗的要求。

基于UWB和RFID的装配式建筑堆场管理系统研究

针对装配式混凝土建筑构件种类繁杂、尺寸较大的特点,在大规模堆场中采用人工或二维码难以有效识别和定位构件,文章基于UWB(超宽带)和RFID(射频识别)技术构建了分为四个层级的堆场管理系统,进而将功能模块划分为识别模块、定位模块、监控模块、数据模块和应用模块,实现对堆场构件的快速识别、精准定位和实时监测,可有效提高堆场利用率、管理效率和质量安全保障程度,促进智能建造技术在装配式建筑实施过程中的应用。

基于STM32和UWB通信的智能搬运小车设计

针对复杂搬运场景固定导引式的智能小车运行的局限性,提出以自由路径导引式进行设计更好的满足搬运需求。利用UWB空间定位技术实现高精度目标跟随,以STM32F103VET6为主控模块,通过各种传感器模块获取信息控制左右电机,以差速驱动的方式控制小车向目标位置移动。通车安装在车身和目标体上的UWB标签模块获取的空间信息,利用定位算法能精确地获取小车相对于目标的空间位置,系统中的超声波传感器、RFID标签传感器、磁条传感器和防撞条等获取多种信息,保障小车能以自由路径导引模式向目标移动。经过测试智能小车在手动模式、跟随模式和循迹模式下,无论空载或负中都能在低中高速下保持良好运行状态,能适应多种复杂场景作业,对于工业自动化具有重要的意义。

HUID:DBN-Based Fingerprint Localization and Tracking System with Hybrid UWB and IMU

High-precision localization technology is attracting widespread attention in harsh indoor environments.In this paper,we present a fingerprint localization and tracking system to estimate the locations of the tag based on a deep belief network(DBN).In this system,we propose using coefficients as fingerprints to combine the ultra-wideband(UWB)and inertial measurement unit(IMU)estimation linearly,termed as a HUID system.In particular,the fingerprints are trained by a DBN and estimated by a radial basis function(RBF).However,UWB-based estimation via a trilateral method is severely affected by the non-line-of-sight(NLoS)problem,which limits the localization precision.To tackle this problem,we adopt the random forest classifier to identify line-of-sight(LoS)and NLoS conditions.Then,we adopt the random forest regressor to mitigate ranging errors based on the identification results for improving UWB localization precision.The experimental results show that the mean square error(MSE)of the localization error for the proposed HUID system reduces by 12.96%,50.16%,and 64.92%compared with that of the existing extended Kalman filter(EKF),single UWB,and single IMU estimation methods,respectively.

基于5G+UWB和惯导技术的井下人员定位系统

针对煤矿井下人员定位系统在实际应用中存在因设备算力与存储资源不足导致无法使用复杂测距与定位算法,定位数据即时传输与响应性能不足,在系统部署方面人力物力损耗较大等问题,提出了一种基于5G+UWB和惯导技术的井下人员定位系统。在末端部署能耗低、抗干扰性强的UWB定位基站,定位基站与5G基站以级联的方式连接,定位基站采集UWB与惯导数据,利用5G网络回传至计算平台,在计算平台上完成定位信息的解算和存储。将基于惯导的人员位置估计作为预测值,将基于UWB的三边定位算法获取的人员位置估计作为观测值,利用卡尔曼滤波器将预测值和观测值进行融合,降低定位误差。在煤矿主体实验基地搭建测试系统,模拟真实煤矿井下环境并进行对比实验。结果表明:(1)在x轴和y轴,融合惯导的卡尔曼滤波算法得出的位置信息和真实位置信息的重合度最高,说明融合惯导的卡尔曼滤波算法得出的位置信息最接近真实位置,平均误差为22.192 cm。(2)5G+UWB和惯导技术组合的井下人员定位系统的位置信息和真实位置信息的重合度最高,误差为[15 cm,20 cm],x轴最大平均误差为26 cm,y轴最大平均误差为24 cm,超过目前大多数井下人员定位系统精度。

一种复杂环境下UWB测距误差预测方法

针对复杂室内环境中,多径干扰和视距遮挡影响室内定位精度的问题,提出一种复杂环境下UWB测距误差的预测方法:根据超宽带(UWB)室内定位方法抗干扰能力强、定位精度高的特点,从理论上分析影响超宽带信号测距精度的因素;然后通过模型量化分析每种影响因素对测距误差的影响程度,改进以往通过信道脉冲响应特征分析单一的视距遮挡参数来提高定位精度的补偿算法;最后从数据挖掘和机器学习的角度出发,将多径效应、视距遮挡、标签与基站的距离、标签移动速度、标签与基站天线俯仰角以及气象因素(温度、湿度、压强)等对测距精度造成影响的重要因素作为特征进行分类和归类,并使用梯度提升决策树模型对数据集进行训练和预测。实验结果表明,该模型可以根据当前状态下的组合特征值估计出测距误差值,将当前预测的误差值补偿到测量值上,可以有效提高超宽带室内定位的精度。

室内轨道公交车UWB定位系统设计

某室内磁悬浮三线轨道公交车采用超宽带(ultra-wideband,UWB)定位,为满足其定位需求,设计了一种室内轨道公交车UWB定位系统,研究了一种神经网络定位算法。该系统采用时分多址和码分多址技术,为多个车辆提供定位服务。神经网络定位算法以UWB测距值作为输入,定位误差作为输出,校正最小二乘法的位置误差。搭建了UWB定位试验系统,结果表明:标签与基站完成组网后,神经网络定位算法的平均定位误差为47.09 mm,均方根误差为30.50 mm,最大误差为152.64 mm,该系统提供了高精度的位置服务。

基于UWB的综采工作面推进度测量系统

针对目前综采工作面推进度的测量和计算方式存在费时费力、累计误差大、传感器损坏后无法重新计算等问题,提出了一种基于UWB测距技术的综采工作面推进度实时测量系统。该系统采用矿用本安型测距分站与测距标志卡组合的方式,通过无线通信实现对综采工作面巷道推进度的实时测量。在综采工作面端头液压支架布置测距分站,在回采巷道固定标志点悬挂测距标志卡,通过巷道内UWB无线信号测距,当即将开采到最近的测距标志卡位置时,撤掉该处测距标志卡,后续测距标志卡接替进行巷道推进度的测量与计算,依此循环往复,不断进行更替测量。结合采煤工艺,建立了依据采煤机位置和液压支架动作的限幅中值平均滤波模型,该模型将限幅滤波、中值滤波、算术平均滤波深度融合,以剔除海量数据中由于受到测量、遮挡等影响而造成的测量偏差较大的无效数据,同时消除有效数据中的最大和最小偏差数据,进一步保证了通过算术平均运算得到的测量值的准确性和有效性,实现了综采工作面推进度的连续测量。地面测试结果表明,测距分站1的最大误差为0.32 m,误差小于0.2 m的占比为84.62%;测距分站2的最大误差为0.48 m,误差小于0.2 m的占比为76.92%。井下工业性试验结果表明:该系统与矿方实测数据日平均推进度差值为0.13 m,证明了UWB测距技术在井下巷道条件下测距的可行性和基于采煤工艺的推进度测量模型的准确性。