基于超宽带的高速无线个域网研究

本文介绍了超宽带技术和无线个域网的概念和基于超宽带技术的高速无线个域网的性能特点及应用，并与其他短距离无线通信方式进行了比较和技术评价，最后对它的局限性、问题和未来发展方向做了仔细分析。     

Design and implementation of enhanced IEEE 802.15.4 for supporting multimedia service in Wireless Sensor Networks

Recently, there has been a growing demand to incorporate multimedia content delivery over the Wireless Sensor Networks (WSNs). This feature could not only enhance several existing applications in the commercial, industrial, and medical domains, but could also spur an array of new applications. However, the efficient gathering of still images, audio, and video information in WSNs imposes stringent requirements on the throughput and energy consumption. Most wireless communication standards with high or moderate data throughputs do not focus primarily on energy efficiency. The IEEE 802.15.4 WPAN standard provides a widely accepted solution for low-cost and low-power wireless communication, with a potential to cater to many types of application scenarios. IEEE 802.15.4 MAC includes features such as its dual operational modes (Non-Beacon-enabled mode/Beacon-enabled mode), which make this standard more attractive for providing multimedia services over the networked sensors. Its Beacon-enabled mode can conserve energy by using the RF sleep mechanism, but it is limited by the lower data throughput. On the other hand, the Non-Beacon-enabled mode can offer higher data throughput but at the expense of significant energy consumption, mainly due to the idle listening problem. In order to overcome these issues, we propose an enhancement to IEEE 802.15.4, named TEA-15.4, which adaptively adjusts the active period based on traffic information. To detect data traffic in the network, the proposed scheme utilizes two techniques: Arbitrary Traffic Signal (ATS) and Traffic Time-Out (TTO). By utilizing these two techniques, the proposed TEA-15.4 can not only support enough data throughput to carry out multimedia communications, but also offer lower energy consumption for the sensing device in WSNs. For performance evaluations, we implement our proposed scheme and the IEEE 802.15.4 full-standard on the TinyOS. Based on the results gathered from testbed experiments and the TOSSIM simulator, TEA-15.4 is shown to be a suitable mechanism for Wireless Multimedia Sensor Networks (WMSNs).     

基于QPSK调制的高速UWB OFDM系统性能分析

多频带方案在多次IEEE无线超宽带标准会议上屡占上风,成为高速UWBWPAN(IEEE802.15.3a)物理层标准提案中极具竞争力的候选技术。针对一种基于QPSK调制技术的高速UWBOFDM系统,探讨了UWBOFDM系统中OFDM参数的选择及其对系统性能的影响。仿真结果证明:理论仿真曲线和未加保护间隔的仿真曲线基本重合;加上保护间隔后的仿真曲线在相同误码率的情况有1dB左右的功率损失;加上卷积编码后系统性能有显著改善。     

无线网络中的无缝漫游实现方法

无线广域网(WWAN)与无线局域网(WLAN)都是近期发展比较成熟的无线网络,将它们很好的结合,是下一代网络(NGN)发展趋势与主题。使用虚拟用户识别模块(SIM)卡认证是在SIM/用户服务识别模块(USIM)模式基础上提出的一种可行性设想,利用蓝牙技术组成无线个人通信网,快速找到虚拟SIM,不需要通过繁复的设置认证,通过把通信任务和进程从应用处理中分离出来,加速了针对无缝漫游新应用的创新。     

超宽带（UWB）无线通信技术分析

超宽带（UWB：ultra—wideband）技术是近几年发展起来的一项十分有潜力的无线通信技术，其高性能、低成本的无线数据通信能力，已成为实现无线个人局域网的富有竞争力的技术之一。文章主要介绍了超宽带技术的特点、基本方案和信道模型，并对比了该技术与其他短距离无线通信技术的优缺点。     

Energy Efficiency of Error Control for High Data Rate WPAN

This paper addresses the issue of energy efficiency for error control mechanisms over WPAN systems. An analytical formulation has been developed to study the trade-off between link layer performance and energy consumption for two types of error control schemes: pure ARQ and type II hybrid ARQ protocol. An MC-CDMA-based system is considered. First of all, the analysis has been used to compare different error recovery schemes from the energy efficiency point of view. Moreover, it has been found that, for any channel conditions, there exists an optimal value of the transmit power that maximizes the energy efficiency. The paper also shows how this result can be used to design the power control of an energy efficient CDMA-based communication system. Mauro De Sanctis received the “Laurea' degree in Telecommunications Engineering from the University of Roma “Tor Vergata' in 2002. He is currently a Ph.D. Student and Assistant Professor in the Department of Electronics Engineering of the same University. He is involved in the DAVID (DAta and Video Interactive Distribution) satellite mission of the ASI (Italian Space Agency); his research is funded by the ASI. He is also involved in the MAGNET (My personal Adaptive Global NET) European FP6 integrated project and in the SatNEx European network of excellence. He worked on Italian national research projects on satellite-terrestrial systems integration such as SHINES (Satellite and HAP Integrated NEtworks and Services) and CABIS (CDMA for Broadband mobile terrestrial-satellite Integrated Systems). On autumn 2004 he joined the CTIF (Center for TeleInFrastructure), a research center focusing on modern telecommunications technologies located at the University of Aalborg (Denmark). His main areas of interest are: integration of different satellite networks, stratospheric platforms and terrestrial networks in a multi-layered fashion, internetworking and resource management in satellite systems and energy efficiency of WPAN systems. Simone Quaglieri received the “Laurea' degree cum laude in Telecommunications Engineering from the University of Roma “Tor Vergata', Italy, in 2004. His thesis, concerning the study of an analytic model for the Raman amplifier in optical systems with high bit rate, has been developed in the same University. During 2002 he worked as stagiaire on the design and development of optical submarine systems at the Elettra company (Telecom Italia group, Italy). He is joining the IRIS (Innovative Radio Integrated Systems) group at the University of Roma “Tor Vergata' as Research Engineer, where he is working on MC-CDMA based technology in the frame of the MAGNET (My Adaptive Global NETwork) European project. He is also working on error recovery mechanisms over satellite systems, and his research is funded by the EC in the frame of the SatNEx (Satellite Network of Excellence) European project. Ernestina Cianca graduated cum laude in Electronics Engineering in 1997 at the University of L'Aquila. She was with Italtel/Siemens (L'Aquila) from 1997 to 1998. She got her Ph.D. degree from the University of Rome Tor Vergata (URTV). The thesis work was on power management in CDMA-based satellite systems. She has been employed by the University of Aalborg, Denmark, in the Wireless Networking Groups (WING), as Research engineer (2000–2001) and as Assistant Professor (2001–2003). In particular, from Sept. 2002 she has been Technical Manager of Aalborg University for the IST-STRIKE project. She is currently Assistant Professor in Telecommunications at the URTV (Dpt. of Electronics Engineering), teaching DSP, Information and Coding. Her research mainly concerns wireless access technologies (CDMA and MIMO-OFDM-based systems), in particular, Radio Resource Management at PHY/MAC layer, ARQ/HARQ, TCP-IP issues over wireless links, integration of terrestrial and satellite systems. She has been the vice-coordinator of the following national research programs: CABIS, on CDMA integrated mobile systems (2000-2002) and SHINES, on satellite-HAP integrated networks for multimedia applications co-financed by MIUR (2002–2004). She is currently working on various European Projects: EU FP6 IP MAGNET (My personal Adaptive Global NET); EU ASIA LINK EAGER-NetWIC (Euro-Asian Network for Strengthening Graduate Education and Research in Wireless Communications); EU Network of excellence NEXWAY. She is author of about 40 papers, on international journals/transactions and proceedings of international conferences. Marina Ruggieri graduated in Electronics Engineering in 1984 at the University of Roma. She was: with FACE-ITT and GTC-ITT (Roanoke, VA) in the High Frequency Division (1985–1986); Research and Teaching Assistant at the University of Roma Tor Vergata (URTV) (1986–1991); Associate Professor in Telecommunications at the University of L'Aquila (1991–1994). Since November 2000 she is Full Professor in Telecommunications at the URTV (Dpt. of Electronics Engineering), teaching DSP, Information and Coding. In 1999 she has been appointed member of the Board of Governors of the IEEE AES Society (2000–2002) and re-elected for the period 2003–2005. Her research mainly concerns space communications and navigation systems (in particular satellites) as well as mobile and multimedia networks. She is the Principal Investigator of: satellite scientific communications missions (DAVID, WAVE) of ASI; national research programs (CABIS) on CDMA integrated mobile systems (2000–2002) and on satellite-HAP integrated networks for multimedia applications (SHINES), co-financed by MIUR (2002–2004). She co-ordinates the URTV Unit in various European Projects: EU FP6 IP MAGNET (My personal Adaptive Global NET); EU ASIA LINK EAGER-NetWIC (Euro-Asian Network for Strengthening Graduate Education and Research in Wireless Communications); EU Network of excellence NEXWAY; GALILEO JU 1st Call – July 2003: VERT (VEhicular Remote Tolling); and in the ASI program on V-band payloads (TRANSPONDERS). She is member of the Editorial Board of Wireless Personal Communications – an International Journal (Kluwer). She was awarded the 1990 Piero Fanti International Prize and she had a nomination for the Harry M. Mimmo Award in 1996 and the Cristoforo Colombo Award in 2002. She is author of about 170 papers, on international journals/transactions and proceedings of international conferences, book chapters and books.     

基于UWB、ZigBee的WPAN与WLAN的干扰

目前,大量的无线设备应用在2.4GHz这一开放频段,很明显各种设备之间存在着潜在的干扰问题,在将来的办公或家庭环境中,如何避免或减少各种WPAN设备与WLAN的相互射频干扰变得日益重要。分析了分别由UWB、ZigBee技术构成的2种新型WPAN设备和WLAN之间的影响,分别从WLAN设备链路的吞吐量和信噪比(RSN)等角度分析了802.11bWLAN与2种短距离技术设备的干扰,并进行了WPAN设备的工程实验和模拟仿真。     

基于改进6LoWPAN的移动物联网性能研究*

主要研究如何解决在无线移动物联网中使用IPv6所引起的传输效率以及移动切换中数据连续传输问题。为传输效率问题,提出了IPv6报头的复合压缩方法,使用了地址分配器、比较编码、Lempel-Ziv-Welch编码器等算法对报头作压缩处理。为实现移动切换时的数据连续传输,提出了改进的移动切换协议E-FHMIPv6方法。仿真结果证明,该算法和方法提高了传输效率,在移动切换时降低了丢包率。因此,提出的解决方案对移动互联网的性能有明显的提高。     

基于ZigBee的WPAN构建方案

无线个人区域网(WPAN)是当前发展最迅速的领域之一，相应的新技术层出不穷。本介绍了一种构建WPAN的新技术——ZigBee的主要特点、相关协议及应用领域，并将其与蓝牙技术进行了比较。     

Cost-aware and Reliable Mesh-under Routing for Delivering IPv6 Packets over Low Power Wireless Personal Area Network

The 6LoWPAN protocol is used in delivering IPv6 packet over IEEE 802.15.4 based low power Wireless personal area network （WPAN）. The Mesh-under routing （MUR） presented in the 6LoWPAN conducts routing in the adaptation layer. When delivering an IPv6 packet over a route consisting of multiple unreliable links, the probability that the IPv6 packet reaches the destination via MUR is very low. This drawback is remedied by the proposed Cost-aware and reliable MUR （CAR-MUR） scheme, which extends the MUR to incorporate a packet redelivery mechanism in the transport layer and is able to find the best number of trials in the transport layer, the best number of the retrials in the MAC layer, and the best number of fragments in each packet so that the total cost for packet delivery is minimized while guaranteeing all the packets to reach the destination with a preset probability. The numerical analysis shows that, compared to the MUR, the proposed CAR-MUR has better performance as it minimizes the packet delivery cost while guaranteeing that all the packets are delivered to the destination with an intended probability.