支持11ac的多功能家庭网关硬件方案设计

设计了一种家庭网关设备,可以实现PON（无源光网络）接入,同时提供有线上网和无线覆盖（WiFi 2.4 GHz 5.8 GHz）、电话、视频服务。用一个设备解决多个家庭设备的联网问题,而且速度较快。在周围用户较多的情况下,能够有较好地用户体验。由于此设备支持大功率WiFi11ac功能,输出功率达20 dBm,可以在2.4 GHz信号密集区域有效避开干扰,同时提供高达1.3 Gbit·s-1的连接速率,可以满足多用户大数据量传输的要求。     

An Adaptive Middleware to Overcome Service Discovery Heterogeneity in Mobile Ad Hoc Environments

Ubiquitous computing research has progressed rapidly over the last few years, and real-world applications, especially mobile networking devices, are booming in consumer markets. With rising industry demand and career opportunities, more and more universities are offering graduates ubiquitous computing courses in addition to classical computer science curricula, such as mobile computing and wireless sensor networks. Here, I outline a graduate-level ubiquitous computing course I taught for final-year master's and first-year doctoral students in Finland at Abo Akademi University in 2006. Finland - the home of Nokia, the world's largest mobile phone maker - has more mobile devices per person than any other country, and its students are very interested in ubiquitous computing technologies. The experiences gained and lessons learned are a good source of information and reference for other educators in this field.     

IEEE 802.11s: WLAN mesh standardization and high performance extensions

In recent years, remarkable market competition and economy of scale has resulted in the price erosion of wireless devices for consumer electronics. Especially for wireless data networks, IEEE project 802 provides the standards for mass markets. With ever-growing usage, the demand for ubiquitous wireless networks increases. However, the achievable data rates decrease with the increasing distance of client devices from the infrastructure, and a sufficiently dense deployment of infrastructure devices is required to fulfill the customers' demand for broadband access. Today, these infrastructure devices rely on a wired backbone for background services; however, to reduce their costly deployment, they should interconnect wirelessly. In this case, devices mutually serve as wireless relays that forward and route packets over multiple wireless hops, and wireless mesh networks come into existence. In this article we provide an overview of wireless mesh networking and provide insights into the related standardization efforts in IEEE 802. For a more in-depth analysis, we focus on the draft WLAN mesh standard IEEE 802.11s and identify challenges for medium access control in multihop communication. Derived from our proposal to 802.1 Is, the current draft incorporates an optional medium access scheme that circumvents a performance gap. By means of simulations, we compare the performance of both solutions and provide an outlook for future 802 wireless systems that will be more reliable.     

3GPP LTE: The Future of Mobile Broadband

The mobile broadband technologies are reaching a commonality in the air interface and networking architecture; they are being converged to an IP-based network architecture with Orthogonal Frequency Division Multiple Access (OFDMA) based air interface technology. From technical perspective, fundamental goal of mobile broadband is to offer higher data rates with reduced latency. The third Generation Partnership Project (3GPP) presents the Long-Term Evolution (LTE) project in order to accommodate increasing mobile data usage and new multimedia applications. In the near future, with the recent progress made by technical specifications and vendor technology demonstrations LTE will emerge as successor to cellular systems as a broadband wireless solution. This paper provides an overview of 3GPP LTE including its history, features, technology, architecture and future. The technology components include OFDMA air-interface, Multiple-Input and Multiple-Output (MIMO) antenna technology and higher order modulation. The architecture includes Evolved Packet Core (EPC) and Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) components. This paper will concentrate to describe the main functions of the most important network elements. Also, the aim of this paper is to present the future potential of LTE which will make it an inevitable choice for wireless network operators around the globe.     

Topics in integrated circuits for communications [Series Editorial]

Over the past several years, mobile personal communication devices have converged to a few popular platforms including the smart phone, personal media player, and personal navigation device. More recently, a miniature laptop known as a netbook has also become increasingly widespread. Common in all these devices is the incorporation of multiple communication functions such as personal navigation, personal area networking, local area networking, wireless personal area networking, TV reception, and mobile cellular networking. Moreover, many of these functions are provided via different communications standards; for example, the Global Positioning System (GPS) for personal navigation, IEEE 802.11a/g/n (otherwise known as Wi-Fi) for wireless local area networking, and Bluetooth and IEEE 802.15.4 (ZigBee) for wireless personal area networking. In the case of TV broadcasting, standards are well established but extremely fragmented. A short list of digital TV broadcast standards includes DVB-H, DVB-T, ISDB-T, T-DMB, CMMB, and MediaFLO. Cellular standards likewise are still fragmented based on GSM/EDGE and WCDMA/UMTS although the cellular industry is working diligently toward a consolidated fourth-generation system based on Third Generation Partnership Project (3GPP) Long Term Evolution (LTE).     

End-user perspectives on home networking

While many families have PCs and broadband modems, connecting them together as a network, especially if they are in different rooms, is challenging. The problems multiply as consumer electronics devices become enabled for broadband and their networking needs diverge. The authors discuss the evolving situation in the home, user needs for networking, and the growing set of problems faced by users. The article describes major home networking approaches and raises some of the questions to be considered in designing home networks for the future     

Voice over wireless local area network

This paper introduces the special issue on voice over wireless local area networks (VoWLAN), which aim to foster interaction among researchers from both academia and industry in networking, wireless communications, and mobile computing. The special issue includes an article investigating the issue of determining an appropriate pricing strategy for VoWLAN provisioning. Also featured are two articles on polling as a solution for supporting real-time traffic over WLANs and another on media optimization network architecture (MONA).     

QoS-enabled residential gateway architecture

As networking technologies penetrate wide varieties of devices for daily usage, home networks are becoming a reality. The bandwidth and always-on connectivity provided by the rapidly growing broadband technologies, such as cable and digital subscriber line (DSL), render home networking even more attractive. A residential gateway is a device that interconnects various home devices to one another as well as to the Internet. The home networks being deployed today are simple and inexpensive with the residential gateway providing only connectivity. As home networks evolve and become more widespread, emerging applications on home networks will demand additional features that require quality of service. We present an architecture of a next-generation QoS-enabled residential gateway. Such a residential gateway, in conjunction with the developments in QoS-enabled wireless LAN technologies, will usher in a new generation of home networks that are capable of supporting a wide range of applications.     

基于ZigBee的物联网智能家居系统

提出了一种物联网智能家居系统,该系统以ARM微处理器LC1813为核心,采用客户端/服务器模式,通过Internet局域网和无线局域网接入到公共网络,在家庭内部通过CC2530无线发送芯片的Zigbee无线网络将家用电器与其他监控设备连接在一起组成无线家庭网络;通过手机客户端和Windows客户端对家庭内部或电器设备进行监控;经实际测试结果表明,系统组网方便、运行稳定,能达到物联网智能家居系统的一般要求。     

Optically Powered Remote Units for Radio-Over-Fiber Systems

Optically powered radio-over-fiber remote units have been designed and constructed for distributed antenna system applications using separate fibers for power and signal transmission. The feasibility of this approach has been investigated through a series of transmission measurements, based on the IEEE 802.11g wireless local area networking standard at a frequency of 2.5 GHz using 64-QAM OFDM modulation at 54 Mb/s. These measurements show that high-quality multilevel signal transmission is possible with modest levels of optical power at the central unit. For example, an EVM of around 3% has been achieved for an RF output power of 0 dBm using a central unit optical power of 250 mW over a link length of 300 m.      

An integrated testbed for wireless multimedia computing

A testbed has been constructed to evaluate node architectures that support multimedia applications and services across a wireless network. Using this testbed, a low bitrate subband video compression algorithm has been prototyped in a field programmable gate array (FPGA) and evaluated for video networking across bandwidth-limited RF channels. A radio interface has been prototyped in an FPGA and a common applications programming interface (API) has been developed to allow experimentation with multiple radios. This testbed has been used to evaluate node performance under two different wireless applications: 1) simultaneous video and data networking (VTALK) and 2) TCP/IP utilities such as FTP and telnet. Based on this evaluation, the design of a battery-operated high throughput wireless multimedia node is presented.     

A paradigm for quality-of-service in wireless ad hoc networks using synchronous signaling and node states

Most limitations in mechanisms geared at achieving quality-of-service (QoS) in wireless ad hoc networking can be traced to solutions based on mapping wireless networks to a wireline paradigm of nodes and links. We contend that this paradigm is not appropriate since links are not physical entities and do not accurately represent the radio frequency (RF) media. Using the link abstraction makes arbitration of the use of the RF media cumbersome leaving only overprovisioning techniques to deliver QoS. In this paper, we argue that an appropriate paradigm should match the physics of the network. The critical resource is electromagnetic spectrum in a space; in turn, this results in a complex paradigm since the part of the spectrum-space that each node wants to use is unique to that node and its destination and will overlap with parts that other nodes may want to use creating interdependences among nodes. This paper describes protocol approaches for access and routing that seek solutions within this wireless paradigm. Access is arbitrated using synchronous signaling and topology is resolved through the dissemination of node states. This approach provides an intuitive framework that provides mechanisms that can be exploited to arbitrate RF media use and implement traffic engineering techniques to deliver QoS. Our proposed approach provides a novel way of tracking the state of the network that can serve as a unified state dissemination mechanism to simultaneously support routing, multicasting, and most QoS heuristics.     

Application-aware dynamic spectrum access

Dynamic Spectrum Access (DSA) allows unlicensed wireless devices to opportunistically access unoccupied licensed spectrum bands. DSA yields efficient spectrum utilization which can greatly improve wireless networking performance. In this paper, we advocate application-awareness to effectively manage the side-effects of DSA that can offset its benefits by adversely impacting application QoS. Simple application hints are found to be able to serve as key inputs in evaluating current spectrum conditions relative to application needs, leading to an informed DSA mechanism that minimizes the impact of undesirable DSA side-effects. Towards this goal, we propose a wireless service architecture called Context-Aware Spectrum Agility (CASA). The key elements of CASA are: (a) semantic dependency equations that provide the relationship between application-layer QoS state and lower-layer DSA parameters, (b) CASA Algorithm that adapts DSA parameters and activities to better suit application needs, and, (c) a low overhead interface to provide application context to DSA. CASA has been explicitly designed with the goals of practical deployment, low overhead operation, and is compatible with any DSA protocol. Compared to state-of-art DSA, the deployment of CASA along with DSA protocols is shown to improve QoS metrics, such as delay and jitter, by an average of 30 and 64%, respectively. CASA is also found to match the application QoS demands for more than 90% of the duration of a communication session—a 300+% improvement over conventional application-agnostic DSA.     

Status and Direction of Communication Technologies - SiGe BiCMOS and RFCMOS

We present the status and direction of silicon semiconductor technologies targeted for applications such as wireless, networking, instrumentation, and storage markets. Various technological aspects for multiple branches of RF foundry technologies that are based on the standard foundry compatible CMOS node are discussed - SiGe BiCMOS HP ("high performance") tailored to high-frequency applications, SiGe BiCMOS WL ("cost performance") tailored to wireless/storage applications, and RF-CMOS optimized for low-cost consumer applications. Future opportunities and challenges for advancement in RF technologies are described in light of CMOS and SiGe heterojunction bipolar transistor scaling. In addition, we discuss the maturity of SiGe BiCMOS by looking at the levels of integration and manufacturability.     

Wireless security study guide: mediocre at best [book review]

This article is a review of the book 'CWSP Certified Wireless Security Professional Official Study Guide (Exam PWO-200)' By Planet3 Wireless published by McGraw-Hill/Osbome, 2003. The book covers a wide range of topics including: local area networks and wireless LAN auditing tools; target profiling; war chalking; social engineering; unauthorized access on wireless LANs; radio frequency jamming; data flooding; wireless client hijacking; US federal regulations regarding information security; corporate policy writing and security best practices; encryption schemes; authentication; virtual private networking; gateway devices; intrusion detection systems; authenticated Domain Name Systems; thin clients; Kerberos; Radius; the Lightweight Directory Access Protocol, and biometrics. The book's goal is to prepare the reader for a certification exam, the reviewer feels the book has little benefit beyond this.     

CASHeW: Cluster-based Adaptive Scheme for Multimedia Delivery in Heterogeneous Wireless Networks

Multimedia streaming over heterogeneous wireless networks has attracted significant interest in recent years from both telecom network operators and end users. However, the heterogeneity of the wireless network makes it very difficult to synchronize real-time multimedia streaming to different types of end-user devices across different wireless networks. In addition, with different delay and packet loss across different networks, multimedia delivery over the heterogeneous wireless networks cannot provide good quality streaming video. This paper proposes CASHeW—a novel cluster-based design with an in-built feedback-based adaptive mechanism that results in a higher video perceived quality in two-hop heterogeneous wireless network environments. CASHeW employs a proxy-client-server mechanism between the base station (BS) and the end-user; and importantly uses a quality-oriented adaptive scheme for efficient multimedia delivery. Simulation-based tests indicate that the performance of CASHeW not only outperforms transport layer adaptive delivery protocols like the TCP-Friendly Rate Control Protocol (TFRCP) and Loss Delay Adaptation (LDA+), but also is better than that of medium access control (MAC) layer protocols such as the Receiver Based Auto Rate (RBAR) and Enhanced Distributed Channel Access (EDCA) in terms of average perceived quality, average bit rate and loss rate.     

Research on Convergence Network of EPON and WiMAX Based on ROF

Convergence of optical and wireless networks is a promising development for future access network architecture. A Radio over Fiber (ROF)-based network that converges Ethernet Passive Optical Network (EPON) and Worldwide Interoperability for Microwave Access (WiMAX) technologies makes it possible to simultaneously transmit EPON baseband signals and WiMAX wireless Radio Frequency (RF) signals. This article elaborates on uplink and downlink transmission, redundancy protection, and roaming features of such a network.     

Multitier Wireless Communications

Next-generation computing systems will be highly integrated using wireless networking. The Rice Everywhere NEtwork (RENÉ) project is exploring the integration of WCDMA cellular systems, high speed wireless LANs, and home wireless networks to produce a seamless multitier network interface. We are currently developing a simulation acceleration testbed and a multitier network interface card (mNIC) consisting of DSP processors, custom VLSI ASICs, and FPGAs for baseband signal processing to interact with the various RF units and the host processor. This testbed will also allow us to explore high performance algorithm alternatives through computer aided design tools for rapid prototyping and hardware/software co-design of embedded systems.     

The package integration of RF-MEMS switch and control IC for wireless applications

The integration of microelectromechanical systems (MEMS) switch and control integrated circuit (IC) in a single package was developed for use in next-generation portable wireless systems. This packaged radio-frequency (RF) MEMS switch exhibits an insertion loss under -0.4 dB, and isolation greater than -45 dB. This MEMS switch technology has significantly better RF characteristics than conventional PIN diodes or field effect transistor (FET) switches and consumes less power. The RF MEMS switch chip has been integrated with a high voltage charge pump plus control logic chips into a single package to accommodate the low voltage requirements in portable wireless applications. This paper discusses the package assembly process and critical parameters for integration of MEMS devices and bi-complementary metal oxide semiconductor (CMOS) control integrated circuit (IC) into a single package.     

Future Applications of Bluetooth

Bluetooth is a short-range radio technology that is increasingly being provided in the various electronic devices that we carry around, such as laptops, mobile telephones and cameras. Bluetooth's supporters claim that it can deliver 'unprecedented productivity' through the seamless interconnection of these devices into a personal area network (PAN) — but does the technology really live up to this expectation? This paper investigates the claims surrounding Bluetooth, and compares its capabilities and potential applications with the existing technologies of DECT and wireless LAN. Bluetooth usage scenarios are considered in the areas of ad hoc networks, the home, the office environment, mCommerce and public access wireless hot-spots. Widespread implementation in devices does not mean widespread usage, and barriers to easy operation are examined to see if Bluetooth can move beyond its personal area network role into new areas of networking that could benefit a broad range of users.