Fluid coding and coexistence in ultra wide band networks

Time Hopping Ultra Wide Band (TH–UWB) commonly encodes the data symbols by shifting the position of the transmitted pulses by a quantity that is quantized over the inter-pulse interval range. In this paper, we relax the hypothesis of a discrete value for the time shift introduced by the TH code, by considering the possibility of generating real-valued codes that introduce time hopping in a “fluid” way. The effect on the power spectral density of generated signals is analyzed, and application of fluid coding to multiple access and to network coexistence is investigated by simulation. Portions of this work were presented at the 2005 2nd International Workshop Networking with Ultra Wide Band, Workshop on Ultra Wide Band for Sensor Networks [M.G. Di Benedetto, G. Giancola, D. Domenicali and P. Ingargiola “Fluid Coding in Time Hopping Ultra Wide Band Networks,” Proceedings of the IEEE 2nd International Workshop Networking with Ultra Wide Band—Ultra Wide Band for Sensor Networks, July 2005, Rome, Italy]. Daniele Domenicali took his Laurea degree in Telecommunications Engineering at the University of Rome La Sapienza in 2004. In November 2004 Domenicali wins the open competition for PhD scholarship in Information and Communication Engineering. He is teaching assistant for the course of “UWB Communication Systems” conducted by Professor Maria Gabriella Di Benedetto at the University of Rome La Sapienza. His research activity includes Pulse Shaping and the related modulation and coding techniques (Time Hopping Coding, PAM and PPM Modulation). Particular attention is paid to the effects produced in the Power Spectral Density, in order to find solutions capable of optimizing spectrum occupation while meeting the constraints imposed by emission masks. Daniele Domenicali is involved in the European Network of Excellence HYCON (Hybrid Control: Taming Heterogeneity and Complexity of Networked Embedded Systems). Guerino Giancola received the “Laurea” degree (magna cum laude) in Telecommunications Engineering, and the Ph.D. degree in Information and Communication Engineering from University of Rome La Sapienza, in 2001 and 2005, respectively. He is currently a research affiliate at the INFOCOM Department at University of Rome La Sapienza, where is actually holding the course of “Electrical Communications” for the degree on Electronic Engineering. His research interests include the analysis and modelling of Multi User Interference in Impulse Radio systems, and the design of Medium Access Control functions and protocols for UWB ad-hoc networks. Guerino Giancola recently co-authored with Prof. Maria-Gabriella Di Benedetto a book on Ultra Wide Band from radio to the network, titled “Understanding Ultra Wide Band Radio Fundamentals” and published by Prentice Hall in June 2004. He is now involved in the European project “PULSERS – Pervasive Ultra wideband Low Spectral Energy Radio Systems” and in the European Network of Excellence “HYCON- Hybrid Control: Taming Heterogeneity and Complexity of Networked Embedded Systems”. Guerino Giancola is a member of the IEEE Communication Society. Maria-Gabriella Di Benedetto obtained her Ph.D. in Telecommunications in 1987 from the University of Rome La Sapienza, Italy. In 1991, she joined the Faculty of Engineering of University of Rome La Sapienza, where currently she is a Full Professor of Telecommunications at the Infocom Department. She has held visiting positions at the Massachusetts Institute of Technology, the University of California, Berkeley, and the University of Paris XI, France. In 1994, she received the Mac Kay Professorship award from the University of California, Berkeley. Her research interests include wireless communication systems and speech science. From 1995 to 2000, she directed four European projects for the design of UMTS. Since 2000, she has been active in fostering the development of Ultra Wide Band (UWB) radio communications in Europe. Within the 5th framework, she directed for the Infocom Dept. two European projects (whyless.com and UCAN) aimed at the design and implementation of UWB ad-hoc networks. Currently, within the 6th EU Framework, her “Networking with UWB” research group participates in the PULSERS Integrated Project which will integrate UWB research and development in Europe for the next years, and in the LIAISON Integrated Project as regards the application of UWB to location-based services. She also participates in the HYCON network of excellence. Dr. Di Benedetto is co-edited several Special Issues on UWB communications and networks for several Journals including IEEE JSAC, Journal of Communications and Networks, Mobile Networks and Applications, Eurasip. In 2004, Dr. Di Benedetto co-authored with G. Giancola the first published book on UWB for communications titled “Understanding Ultra Wide Band Radio Fundamentals” and published by Prentice Hall. She recently completed the co-edition of two new books on UWB that will be published by 2005: UWB Communication Systems - A comprehensive overview, with T. Kaiser, D. Porcino, A. Molisch, and I. Oppermann, Hindawi Publishing Corporation, 2005, andUltra Wideband Wireless Communications with H. Arslan and Z.N. Chen, John Wiley & Sons, Inc., 2005.     

Introducing consciousness in UWB networks by hybrid modelling of admission control

We formalize a model for a self-organizing network of nodes that operate according to the UWB principle based on hybrid modelling formalism. We design the rules that lead to the formation of the network and in particular an admission control procedure that is capable to handle both continuous and discrete perturbations, while maintaining the network in a condition of stability. Cognition is introduced in the model by allowing nodes to adjust their rules of operation based on the perception of the environment by an elected node, serving as the observer, that is aware of context, evaluates, and selects one strategy of operation. Maria-Gabriella Di Benedetto obtained her Ph.D. in Telecommunications in 1987 from the University of Rome La Sapienza, Italy. In 1991, she joined the Faculty of Engineering of University of Rome La Sapienza, where currently she is a Full Professor of Telecommunications at the Infocom Department. She has held visiting positions at the Massachusetts Institute of Technology, the University of California, Berkeley, and the University of Paris XI, France. In 1994, she received the Mac Kay Professorship award from the University of California, Berkeley. Her research interests include wireless communication systems and speech science. From 1995 to 2000, she directed four European projects for the design of UMTS. Since 2000, she has been active in fostering the development of Ultra Wide Band (UWB) radio communications in Europe. Within the 5th framework, she directed for the Infocom Dept. two European projects (whyless.com and UCAN) aimed at the design and implementation of UWB ad-hoc networks. Currently, within the 6th EU Framework, her “Networking with UWB” research group participates in the PULSERS Integrated Project which will integrate UWB research and development in Europe for the next years, and in the LIAISON Integrated Project as regards the application of UWB to location-based services. She also participates in the HYCON network of excellence. Dr. Di Benedetto has co-edited several Special Issues on UWB communications and networks for several Journals including IEEE JSAC, Journal of Communications and Networks, Mobile Networks and Applications, Eurasip. In 2004, Dr. Di Benedetto co-authored with G. Giancola the first published book on UWB for communications titled “Understanding Ultra Wide Band Radio Fundamentals” and published by Prentice Hall. She recently completed the co-edition of two new books on UWB that will be published by 2005: UWB Communication Systems—A comprehensive overview, with T. Kaiser, D. Porcino, A. Molisch, and I. Oppermann, Hindawi Publishing Corporation, 2005, and Ultra Wideband Wireless Communications with H. Arslan and Z.N. Chen, John Wiley & Sons, Inc., 2005. Maria Domenica Di Benedetto obtained the “Dr. Ing.” degree (summa cum laude) of Electrical Engineering and Computer Science, University of Roma “La Sapienza” in 1976 (Mosè Ascoli Best Student Award). In 1981, she obtained the degree “Docteur-Ingénieur” and in 1987 the degree “Doctorat d’Etat ès Sciences”, Université de Paris-Sud, Orsay, France. From 1979 to 1983, she had been Research Engineer at the scientific centers of IBM in Paris and Rome. From 1983 to 1987, she had been Assistant Professor at the University of Roma “La Sapienza”. From 1987 to 1990, she had been Associate Professor at the Istituto Universitario Navale of Naples. From 1990 to 1993, had been Associate Professor at the University of Roma “La Sapienza”. Since 1994, she has been Professor of Control Theory at University of L’Aquila. From 1995 to 2002, she was Adjunct Professor, Department of EECS, University of California at Berkeley. In 1987, she was Visiting Scientist at MIT; in 1988, 1989 and 1992, Visiting Professor at the University of Michigan, Ann Arbor; in 1992, Chercheur Associé, C.N.R.S., Poste Rouge, Ecole Nationale Supérieure de Mécanique, Nantes, France; in 1990, 1992, 1994 and 1995, McKay Professor at the University of California at Berkeley. Her research interests revolve around nonlinear control and hybrid systems. She was Associate Editor of the IEEE Transactions of Automatic Control and has been Subject Editor of the International Journal of Robust and Nonlinear Control since 1995. Since 2005, she has been a member of the IFAC Technical Committee on Discrete Event and Hybrid Systems. Since 2000, she has been the Director of the Center of Excellence for Research DEWS on “Architectures and Design methodologies for Embedded controllers, Wireless interconnect and System-on-chip”, University of L’Aquila. She is IEEE Fellow and Chairperson of the Standing Committee on Fellow Nominations, IEEE Control Systems Society. Guerino Giancola received the “Laurea” degree (magna cum laude) in Telecommunications Engineering, and the Ph.D. degree in Information and Communication Engineering from University of Rome La Sapienza, in 2001 and 2005, respectively. He is currently a research affiliate at the INFOCOM Department at University of Rome La Sapienza, where is actually holding the course of “Electrical Communications” for the degree on Electronic Engineering. His research interests include the analysis and modelling of Multi User Interference in Impulse Radio systems, and the design of Medium Access Control functions and protocols for UWB ad-hoc networks. Guerino Giancola recently co-authored with Prof. Maria-Gabriella Di Benedetto a book on Ultra Wide Band from radio to the network, titled “Understanding Ultra Wide Band Radio Fundamentals” and published by Prentice Hall in June 2004. He is now involved in the European project “PULSERS—Pervasive Ultra wideband Low Spectral Energy Radio Systems” and in the European Network of Excellence “HYCON—Hybrid Control: Taming Heterogeneity and Complexity of Networked Embedded Systems”. Guerino Giancola is a member of the IEEE Communication Society.     

Ultra Wide Band WLANs: A Self-Configuring Resource Control Scheme for Accessing UWB Hot-Spots with QoS Guarantees

In the framework of wireless access networks the Hot-Spot concept is attracting several operators. In a Hot-Spot near stationary terminals may reach one or more Radio Access Points (RAP) offering wireless access to the fixed network. Mobile terminals should be able to register to the network, associate to a RAP and activate a wireless communication supporting given bit rates and Quality of Service (QoS) features. Several mobile users, requiring different services, enter and exit the Hot-Spot. In this scenario network operators should have the opportunity to configure quickly radio resources to serve the mobile terminals and to handle efficiently the network resources in order to maximize the income. Among the different technologies emerging in this field, we investigate the feasibility of a wireless access based on Ultra Wide Band (UWB) radio, combined with a flexible admission control scheme based on transmission power selection. We employ UWB in unlicensed mode, i.e., we operate in accordance to the limits imposed by the regulatory bodies (e.g., US Federal Communications Commission). The flexibility of the admission control depends mainly on the capability of a mobile terminal of “measuring” the environment it is entering and thus supporting the RAP in the selection of the appropriate transmission parameters. The proposed approach provides an admission policy based on the Maximum Extra Interference (MEI) and selects the power level through a simple interaction among the involved mobile terminals. The information for basing the decision on is collected through measurements and signaling. In order to increase the system efficiency, transmission parameters are selected in accordance to a “balancing” criterion (thus Balanced-MEI, B-MEI). The B-MEI approach keeps quite simple the admission of new mobile terminals in a RAP’s area but contemporarily satisfies the trade-off between fair resource assignment and system efficiency. This is a key trade-off in wireless access systems where interference effects determine the upper limit of the number of users that can be admitted in the network.Francesca Cuomo received her “Laurea” degree in Electrical and Electronic Engineering in 1993, magna cum laude, from the University of Rome “La Sapienza”, Italy. She earned the Ph.D. degree in Information and Communications Engineering in 1998, also from the University of Rome “La Sapienza.” Since 1996 she is an Assistant Professor at the INFOCOM Department of this University. Her main research interests focus on broadband integrated networks, Intelligent Networks, architectures and protocol for wireless networks, mobile and personal communications, Quality of Service guarantees and real time service support in the wired and wireless Internet.She participated in: (I) the European ACTS INSIGNIA project dedicated to the definition of an Integrated IN and B-ISDN network; (III) IST WHYLESS.COM project focusing on adoption of the Ultra Wide Band radio technology for the definition of an Open Mobile Access Network; (III) RAMON project, funded by the Italian Public Education Ministry, focused on the definition of a reconfigurable access module for mobile computing applications. She is now participating to the European IST ePerSpace Project focusing on the support of personalized audio/video services at home and everywhere. She is also involved in FIRB project VIRTUAL IMMERSIVE COMMUNICATIONS (VICOM) where she is responsible of the research activities on the BAN and PAN networks.Dr. Cuomo is in the editorial board of the Elsevier Computer Networks journal and she has served on technical program committees and reviewer in several international conferences and journals including ACM Wireless Mobile Internet Workshop, IEEE ICC and GLOBECOM, IEEE Trans. on Wireless Communications and IEEE Journal on Selected Areas on Communications.Cristina Martello received her Laurea degree in Electronic Engineering (magna cum laude) in July 2000 from Università di Roma “La Sapienza”. She earned the PhD degree in Information and Communications Engineering in February 2004 (Università di Roma “La Sapienza”).Since January 2001 she has been working in the IST European HYPERLINK “/” “_blank” Whyless.com project on an open mobile access network based on the Ultra Wide Band radio technology. She collaborated with HYPERLINK “http://www.coritel.it/” “_blank” Co.Ri.Tel. (a research consortium on Telecommunications) as a fellowship holder in 2000/2001 for the project SWAP on the feasibility of a re-configurable software module for the dynamic Radio Resource Control in the 3G of mobile wireless systems, and in 2002 for the project PRESTO.Her main research interests regard the developing of flexible and distributed Radio Resource Control techniques for “ad-hoc like” networking paradigms.     

Antennas and Propagation Measurement Techniques for UWB Radio

The progressive development of Ultra Wide Band (UWB) antennas and microelectronics allows for a wide range of future UWB radio communication applications. The paper focuses on testing and measuring various antennas and propagation aspects important in UWB radio. The ‘Delft approach’ of measuring UWB antennas using time-domain measurement techniques is explained including the diagnostics of antenna mismatch and wave scattering from the inside and the antennas environment. The approach is illustrated with measurements.The experimental time-domain set up allows instantaneous measurements up to 26GHz. After an overview of various UWB antennas some latest developments of a miniaturized antenna are reported. UWB channel measurements in ‘short-range radio’ illustrates that good insight in the propagation of short radar pulses can be obtained. Leo P. Ligthart was born in Rotterdam, the Netherlands, on September 15, 1946. He received an Engineer's degree (cum laude) and a Doctor of Technology degree from Delft University of Technology in 1969 and 1985, respectively. He is fellow of IEE and IEEE. He received Doctorates (honoris causa) at Moscow State Technical University of Civil Aviation in 1999 and Tomsk State University of Control Systems and Radioelectronics in 2001. He is academician of the Russian Academy of Transport. Since 1992, he has held the chair of Microwave Transmission, Radar and Remote Sensing in the Department of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology. In 1994, he founded the International Research Center for Telecommunications and Radar (IRCTR) and is the director of IRCTR. Prof. Ligthart's principal areas of specialization include antennas and propagation, radar and remote sensing, but he has also been active in satellite, mobile and radio communications. He has published over 300 papers.     

The ultra-wide bandwidth outdoor channel: From measurement campaign to statistical modelling

This paper proposes an investigation of the propagation behaviour for Ultra-Wide Bandwidth (UWB) signals in outdoor environments. Specifically, we first report on the results of an extensive measurement campaign carried out in three selected scenarios, namely “forest”, “hilly” and “sub-urban” environments. Then, we present the statistical model derived through the post-processing of collected samples by the CLEAN algorithm. While an extensive collection of results is provided in the paper, the main achievements can be summarized as follows: (i) the path-loss exponent varies from 2 to 3.5 and depends on the reference scenario and on the height of transmission and reception equipments with respect to the ground floor, (ii) the local mean of the received power experiences a Log-Normal shadowing with a standard deviation that may depend on the azimuth position, (iii) the statistics of the first received echo in the small-scale analysis also well fit a Log-Normal distribution; (iv) the delay spread in the small-scale multipath scenario turns out to be quite small (i.e. roughly 10 ns in the forest scenario and less than 32 ns in the sub-urban scenario). Marco Di Renzo (S’05) received the laurea degree (cum laude) in Electronic Engineering from the University of L’Aquila, Italy, in 2003. In 2002 he was with the Center of Excellence in Research DEWS (Design Methodologies for Embedded Controllers, Wireless Interconnections and System–on-Chip) at the Department of Electrical Engineering, University of L’Aquila, doing research on the analysis and design of Ultra Wide Band digital receiver architectures. Since 2003 he has been with the Department of Electrical Engineering, University of L’Aquila, where he worked on channel sounding and modelling for Ultra Wide Band systems and where he is currently pursuing his Ph.D. degree in Electric and Information Engineering. His current research activity is focused on channel modelling, synchronization and detection theory with specific interest to the Ultra Wide Band technology. In 2004 he played a key role in the successful creation of WEST Aquila S.r.l. (Wireless Embedded Systems Technologies Aquila), a R&D Spin-Off of the University of L’Aquila and the Center of Excellence in Research DEWS, where he currently holds the position of research engineer. Fabio Graziosi (S’96–M’97) was born in L’Aquila, Italy, in 1968. He received the Laurea degree (cum laude) and Ph.D. degree in electronic engineering from the University of L’Aquila, L’Aquila, Italy, in 1993 and 1997, respectively. Since February 1997 he has been with the Department of Electrical Engineering, at the University of L’Aquila, where he currently holds the position of Associate Professor. His current research interests are mainly focused on wireless communication systems with emphasis on wireless sensor networks and ultra wide band communication techniques. He is involved in major national and European research projects in the field of wireless systems. He is member of the Executive Committee of the Center of Excellence DEWS and serves as Chairman of the Board of Directors of WEST Aquila S.r.l., a Spin-off R&D Company of the University of L’Aquila and Center of Excellence DEWS, founded in December 2004. Riccardo Minutolo works in Thales Italia in the R&D department. He graduated in Electronic Engineering in the University of L’Aquila, in 1999. He joined Thomson-csf in 1999 working as junior engineer in the Radio propagation, interference and software development. In that period he gained expertise in HF, VHF, UHF, SHF radio propagation. In 2002 he joined Thales Italy (ex-Thomson-csf) working in the ad hoc networking area. In 2002 he was the National coordinator of a 3 years European international project (Euclide UWB). The Euclide UWB project aimed to study and research the potentiality of the emerging UWB technology for civil security and military purposes. Since 2002 his major areas of interest are: radio propagation, UWB physical layer, MAC and networking. Mauro Montanari was born in 1950 in Rimini and graduated in Electronic Engineering at Bologna University in 1974. He joined in 1976 Telettra, a national telecommunication company, working since the beginning in Defence R&D activities. His first experience was in the field of advanced automatic antenna matching unit in HF band. Afterwards he mastered, staying for several time periods in TRW—Redondo Beach/California, the technical issue of protecting radio communications through Spread Spectrum communications systems, in view of an important application to a new generation of tactical radio systems in VHF frequency band. On this topic he is co-author, with Prof. S. Pupolin of Padua University, of the book “Spread Spectrum Communications Systems” Collana Scientifica Telettra). From 1991 to 1998 he was responsible of the R&D Department within the Defence Division of Alcatel Italia (formerly Telettra) and in this position he managed several R&D projects: (i) Triservice Digital Network for the Italian MOD, in cooperation with Selenia Communications; (ii) SCRA (Single Channel Radio Access) and network management system for the Italian Army tactical network (SOTRIN) as a partner of Catrin Consortium; (iii) A new generation of radio equipment in HF band for fixed applications; (iv) High speed HF modem, according to several NATO waveforms; (v) HF fixed network for Italia Ministry of Foreign Affairs; (vi) Wide band Interception and jamming systems in HF band. Since 1999, he is responsible, within Thales Italia SpA—Land and Joint Systems Division, of Advanced Studies area with the task of promoting in the company new emerging technologies, specifically in the field of Wireless LAN, Tactical Internet, sensor networks, Ultra Wide Band for military applications and plasma antennas. This role includes establishing relations with most Thales R&D centres located in Europe and promoting new cooperative activities in new advanced technological areas. He also manages scientific relation with several Italian Universities. Fortunato Santucci (S’93–M’95–SM’00) was born at L’Aquila, Italy, in 1964. He received the laurea degree and the Ph.D. degree in Electronic Engineering from the University of L’Aquila, Italy, in 1989 and 1994, respectively. In 1989 he was with Selenia Spazio S.p.a., Rome, working on VSAT networks design. In 1991–1992 he was at the Solid State Electronics Institute (I.E.S.S.) of the National Research Council (C.N.R.), Rome, doing research on superconductor receivers for millimeter wave satellite systems. Since 1994 he has been with the Department of Electrical Engineering, University of L’Aquila, where he currently holds the position of Associate Professor. In 1996 he was a visiting researcher at the Department of Electrical and Computer Engineering of the University of Victoria, BC, Canada, where he researched on CDMA networks. His current research activity is focused on communication theory, access control and radio resource management in wireless systems, with special emphasis on technologies for networked embedded systems. He has participated in major national and European research programs in wireless mobile communications and coordinates research programs funded by industrial partners. He has been a reviewer for major technical journal in telecommunications and a session chairman in various conferences. He currently serves as an Editor for the IEEE Transactions on Communications and Kluwer Telecommunications Systems. He has been/is in the TPC of several conferences in communications. He is a Senior Member of the IEEE and is a member of the Communications Theory Committee. He is in the Executive Committee of the Center of Excellence DEWS at the University of L’Aquila and in the Executive Committee of CNIT.     

基于FPGA的UWB雷达PPM调制解调系统

超宽带UWB无线通信技术是一种基于直接发射窄脉冲的新技术,因其具有低功耗、良好的抗干扰和抗多径能力、穿透性能好等特点,特别适用于隐藏活动目标检测和近距离数据传输。用于检测隐藏活动目标的超宽带雷达就是基于基带无载波极窄脉冲的,有着广阔的应用前景。对比超宽带的多种调制解调方式选取了脉冲位置调制。介绍了使用Verilog语言在FPGA上实现PPM调制解调器,实现了UWB雷达发送窄脉冲进行基带调制。     

基于Dechirp和多相滤波结构的超宽带通信系统

该文提出了一种采用Dechirp和复多相滤波器组的超宽带通信系统。其发射信号采用开关键控(OOK)调制和Chirp扩频,接收信号经过Dechirp脉冲压缩、低通滤波和模数转换后,使用复多相滤波器组进行子信道划分,完成子信道选择和最大比合并,最后进行粗同步、精同步、信噪比估计和基于能量检测的OOK解调。通过理论推导与仿真实验,分析了在AWGN信道,IEEE 802.15.3a的CM1和CM4信道下该超宽带通信系统的性能。分析结果证明,该通信系统可以获得较高的处理增益和较强的抗多径性能,所以适合应用于拓展距离通信。     

超宽带无线通信系统的调制方式研究

超宽带技术是目前无线通信中非常有发展前途的技术.本文介绍了超宽带通信的基本原理,着重分析了目前使用的几种调制方法,简要说明了各种调制方法的频谱特性,并比较了这些调制方法的性能.     

Programmable CNN Analogue Chip for RD-PDE Multi-Method Simulations

Cellular Non Linear Networks can be useful applied for the solution of several types of Partial Differential Equations (PDEs). This paper will describe an analogue circuit implementation for the simulation of one-dimensional Reaction-Diffusion PDE with the possibility to set different boundary conditions as well as to select different discretization methodologies. Fausto Sargeni was born in Riano (ROMA) in 1961. He received the Dipl. Eng. degree in Electronic Engineering at the University of Rome “La Sapienza" in 1987. In 1989 he jointed the Dept. of Electronic Engineering at the University of Rome “Tor Vergata" as Assistant Professor. In 1998 he became Associate Professor. His research interests include analog VLSI circuits for non linear circuits and high-speed interconnections. Vincenzo Bonaiuto was born in Rome, Italy, in 1962. He received the Dipl. Eng. degree in Electronic Engineering at the University of Rome “La Sapienza". In 1997 he received the the Ph.D. in Telecommunication and Microelectronics. In 1996 he jointed the Electronic Engineering Dept. as Assistant Professor at the University of Rome “Tor Vergata” and, in 2002, he became Associate Professor. His main research interests are in the area of non linear circuits, Artificial Neural Networks analogue/digital VLSI circuits implementation.     

A Novel Approach for the Link Layer in Impulse-based UWB Ad Hoc Networks

Ultra Wide Band (UWB) impulse radio, promises to be suitable for short-range, low-power, low cost and high data rate applications. While most UWB research is concentrating on the physical layer, little research has been published on the link layer. The fundamental operations in the link layer need to take into account the specifics of impulse radio and also the particular features of ad hoc networks. A novel self-organizing link layer protocol based on time hopping impulse radio, called SDD, was proposed by the authors. This protocol is a collision-free mechanism that enables the devices to discover neighboring nodes and arrange the access to communication resources shared among the nodes. In this paper, some issues related to the self-organizing link layer based on UWB impulse radio are investigated and addressed. The SDD protocol is further developed and specified in detail. The simulations are carried out using GloMoSim simulation environment. An SDD module has been developed and embedded in the simulator. Results show that the SDD protocol can work properly and efficiently in a single-hop ad hoc network.     

基于OFDM的UWB系统研究

UWB无线通信是未来最富有竞争力的无线通信技术之一。介绍了一种基于正交频分复用的超宽带(OFDM-UWB)系统的结构,详细分析了电路的主要构成:模数转换器、低噪声放大器、脉冲发生以及他们和系统功耗的联系;介绍了OFDM-UWB信号的处理过程,并探究了消除接收到的UWB信号中窄带干扰(NBI)信号的方法,该方法有效地提高了OFDM-UWB系统的抗干扰性。     

噪声干扰对超宽带通信干扰效果分析

从通信干扰角度,基于频域分析方法,针对跳时-脉冲位置调制-超宽带（TH-PPM-UWB）体制,分析了不同噪声干扰信号对通信系统的干扰效果,并运用MATLAB仿真软件,在AWGN信道下,对不同噪声干扰信号的干扰效果进行了蒙特卡洛实验仿真,并对实验结果进行了对比分析,给出了干扰效果（误比特率）与噪声干扰信号功率、带宽和中心频率的关系。为实现对超宽带通信系统干扰的实装研制打下理论基础,具有一定的军事价值。     

Single-chip CMOS pulse generator for UWB systems

This paper presents a single-chip pulse generator developed for Ultra Wide Band (UWB) wireless communication systems based on impulse radio technology. The chip has been integrated in a CMOS 130-nm technology with a single supply voltage of 1.2 V. The basic concept is to combine different delayed edges in order to form a very short duration "logical" pulse, and then filter it, so as to obtain an UWB pulse. It is possible to vary the output pulse shape, and thus the corresponding spectrum, just by acting on the delayed edge combination. Furthermore, the pulse generator supports both position modulation (2-PPM) and polarity modulation (BPSK modulation) in order to convey data through the air. Its power consumption remains less than 10 mW for a raw data rate of up to 160 Mb/s. Spectral and temporal measurements of the single-chip pulse generator are presented with an illustration of the modulation effects on the power spectral density (PSD).     

基于频域的低频UWB SAR极化校准

多极化,低频超宽带(Ultra Wide Band, UWB)合成孔径雷达(Synthetic Aperture Radar, SAR)是雷达技术未来发展的一个重要方向。系统的低频特性,UWB特性和大处理角特性使得常规SAR极化校准不再适用。该文基于多极化低频UWB SAR频域处理模型,考虑了极化校准中定标体的低频超宽带电磁散射特性的问题,给出了极化校准方法。计算机仿真验证了该方法的有效性。     

超宽带带通滤波器设计与实现

通过对传统滤波器预畸设计法进行改进,得到一种新型的带通滤波器设计公式,它克服了在采用电容耦合或电感耦合带宽过窄及线性相位的问题.使用此方法设计了一个超宽带线性相位带通滤波器,并通过实验仿真证明其可行性.     

UWB通信信号选择与系统性能仿真

本文通过对具有相同能量和相同脉宽的不同 UWB( Ultra Wide Band)脉冲信号在脉位调制 ( PPM,Pulse Position Modulation)和脉幅调制 ( PAM,Pulse Amplitude Modulation)方式下的抗噪声性能的理论分析与仿真对比 ,研究了在 AWGN( Additive White Gaussian Noise,加性高斯白噪声 )条件下 ,不同调制方式下脉冲波形的选择与系统性能之间的关系     

基于Hermite 插值滤波器的直接延时补偿超宽带波束形成技术研究

超宽带(UWB)信号波束形成是UWB 雷达的关键性技术。传统的波束形成方法存在瞬时带宽和扫描角度受限,波束偏移等问题,直接延时补偿法是避免上述问题的有效途径。该文提出了基于Hermite 插值滤波器的直接延时补偿波束形成方法,理论分析和仿真结果均表明Hermite 插值滤波器幅频特性和群时延特性优于目前常用的Lagrange 和径向基插值滤波器。超宽带线性调频信号实例仿真也表明了该方法在超宽带波束形成性能方面的优越性。      

A VLSI Implementation of Low Power, Low Data Rate UWB Transceiver for Location and Tracking Applications

A low power, low data rate ultra wideband (UWB) impulse radio transceiver for location and tracking applications is presented in this paper. The UWB receiver is based on a non-coherent, energy collection approach, which makes the receiver highly independent of the shape of the transmitted waveform. The UWB signal is generated by a pulse generator and band-pass filter fixing the signal bandwidth to 1 GHz in the band from 3.1 GHz to 4.1 GHz. The modulation scheme used in this time division multiple access system (TDMA) is Binary Pulse Position Modulation (BPPM). In this paper the system concept, system architecture and RF parts of the VLSI implementation are peresented. The transceiver is implemented in a 0.35 μm SiGe process provided by Austria Microsystems. Sakari Tiuraniemi was born in Kolari, Finland, on March 10, 1977. He received his M.Sc. degree in 2003 in electrical engineering from the University of Oulu, Finland, where he then continued his research on transceiver integration and implementation issues for two years. In 2005 he joined the CERN in Geneva, Switzerland, where he is working towards the PhD degree in electrical engineering. His current research focuses on detector readout electronics for high energy physics applications. Lucian Stoica was born in Roman, Romania, on December 8, 1975. He received the M.S. degree in electrical engineering from the Technical University of Iasi, Romania, in 2000. He was with Telecommunications Department at the Technical University of Iasi from 2000 to 2003. As a teaching assistant he was involved in development of digital design and FPGA prototyping. In 2003, he joined Centre for Wireless Communications, University of Oulu, Oulu, Finland where he is working towards the PhD degree in electrical engineering. His current research focuses on low complexity SiGe BiCMOS circuit transceivers design for wireless communications, particularly on ultrawideband impulse radio systems. Alberto Rabbachin received the M.S. from the University of Bologna, Italy, in 2001. In 2001, during his undergraduate studies, he visited the Centre for Wireless Communications, University of Oulu, Finland. In 2002 he joined Agilent Technologies for an internship and since 2003 he is working towards the PhD degree at the Centre for Wireless Communications. His research interests include UWB systems with emphasis on receiver structures, synchronization and ranging techniques. Ian Oppermann was born in Maryborough, Australia, in 1969. He completed a BSc, BE and PhD at the University of Sydney Australia in 1990, 1992 and 1997, respectively. His PhD was related to physical layer aspects of novel spread spectrum/CDMA systems. In 1996 he founded SP Communications, a company which developed network planning tools for 3G mobile systems and IP cores for WLAN chipsets. He became a Docent (Adjunct Professor) at the University of Oulu, Finland in 2001 and subsequently joined the Centre for Wireless Communications (CWC) in 2002 as Assistant Director, becoming Director in 2003. From the beginning of 2005 is the acting Director for Short Range Communications Research at CWC. His main research interests are spread spectrum systems and UWB. Dr. Oppermann has co-edited several books, holds several patents for wireless communications and has over 80 publications in international journals and conferences.     

脉冲卷积干扰技术在超宽带SAR中的应用分析

为探讨脉冲卷积干扰技术在超宽带SAR中应用的可行性,详细分析了距离像和二维像的干扰效果,发现在二维图像中,方位向的聚焦性能明显下降。通过对目标回波和干扰信号处理流程的分析,发现超宽带SAR空变特性是导致二维图像散焦的根本原因。提出对干扰信号进行相位调制,调整干扰信号的分布曲线,以降低空变特性的影响,取得了较好的干扰效果。研究表明,距离向的干扰效果与常规雷达一致,可以形成滞后的假目标欺骗干扰,改进的脉冲卷积干扰大大提高了方位向聚焦性能,用于对超宽带SAR进行假目标干扰。仿真结果验证了理论分析的正确性。     

超宽带时域近距离高分辨ISAR成像

近距离目标超高分辨率微波成像技术在安全检测、非破坏性控制、生物医学等领域中有着非常重要的应用价值和广阔的应用前景。该文利用基于窄脉冲形式的超宽带时域雷达系统研究近距离目标的高分辨率ISAR成像,给出了仿真和实测结果。利用转台旋转目标,基于超宽带脉冲源和超宽带收发天线以及高性能取样示波器,配以同步触发脉冲和自行研发的数据采集软件,搭建了该时域雷达实验系统,提出了准确获取目标回波信息的实验条件,和实现回波延时精确校正的误差补偿方法。并针对采样时间窗内的杂波干扰,讨论了时域后向投影算法(Back Projection,BP)与背景对消技术相结合的成像算法,实现了分辨率为8 mm的近距离目标的成像,准确地反映了目标的位置、形状和大小等信息。