Broadband wireless access

This article reviews the technologies and potential markets, applications, and architectures for broadband wireless access. The emergence of wireless communications for cellular systems is presented, together with its projected future evolution to mobile wideband systems. The field of broadband access systems, services, and network architectures is also covered, and then systems for broadband wireless communications for indoor local area networks and outdoor public fixed access networks are discussed. Broadband wireless access systems are emerging as a new and growing area of telecommunications, since the ability to provide access without extensive installation of copper or fiber infrastructures make wireless technology well suited for broadband services. Finally, some of the key enabling technologies, such as adaptive antennas and video compression, and the future architectural directions of broadband wireless networks are presented     

Next-generation wireless communications concepts and technologies

Next-generation wireless (NextG) involves the concept that the next generation of wireless communications will be a major move toward ubiquitous wireless communications systems and seamless high-quality wireless services. This article presents the concepts and technologies involved, including possible innovations in architectures, spectrum allocation, and utilization, in radio communications, networks, and services and applications. These include dynamic and adaptive systems and technologies that provide a new paradigm for spectrum assignment and management, smart resource management, dynamic and fast adaptive multilayer approaches, smart radio, and adaptive networking. Technologies involving adaptive and highly efficient modulation, coding, multiple access, media access, network organization, and networking that can provide ultraconnectivity at high data rates with effective QoS for Next Gare are also described     

移动通信技术的发展方向——第三代移动通信技术的改进及三代后技术

根据国际上的最新进展,本文对移动通信技术的发展方向进行了讨论和介绍。在第三代移动通信标准和技术的基础上,国际上已经开始讨论如何完善和发展。在移动通信的性能和带宽方面,考虑了传输更高速率和提供宽带业务的可能性;在空间接口技术方面,对智能天线、软件无线电、高速数据传输等技术予以了高度重视;在核心网方面,则是全IP核心网的概念。显然,TD－SCDMA系统已经在这些方面先走了一步,但还远远没有达到上述技术所能达到的目标。     

Spectrum considerations for public safety in the United States

Since the inception of mobile radio, public safety agencies have relied on wireless communication systems to coordinate day-to-day and emergency operations. The decentralized and autonomous nature of the various public safety agencies in the United States has led to the deployment of a variety of systems operating in a fragmented spectrum, ranging from lower VHF to upper UHF. Due to the narrowband technologies used in public safety communications systems, public safety agencies have been limited primarily to voice services and low-speed data transfer on their private networks. In contrast, the commercial cellular sector now offers a large portfolio of services that include voice, messaging, email, Web browsing, picture transfer, video streaming, and other wideband services. In this article, some of the factors driving the expansion of spectrum allocated to public safety agencies arc described.     

Wireless communications in the twenty-first century: a perspective

Wireless communications are expected to be the dominant mode of access technology in the next century. Besides voice, a new range of services such as multimedia, high-speed data, etc. are being offered for delivery over wireless networks. Mobility will be seamless, realizing the concept of persons being in contact anywhere, at any time. Two developments are likely to have a substantial impact on the mobile communications systems deployed in the twenty-first century: the adoption of International Mobile Telecommunications-2000 and wireless asynchronous transfer mode (ATM). They are two different but cooperative approaches to providing high-speed wireless access. The limitations of the radio-frequency spectrum and radio channel propagation impose special constraints on the technologies of systems to be deployed. To make future mobile systems globally acceptable, standardization efforts are underway in the International Telecommunications Union and the ATM Forum. This paper reviews the international standardization efforts, the challenges to the technologies imposed by the radio spectrum limitations, radio channel propagation-induced distortions, and possible solutions. Evolution, migration, and architecture issues also are discussed     

第4代移动通信的几种制式特点及应用前景

随着移动通信技术的发展,将迎来第4代移动通信时代。它能达到更快的数据传输速率,提供优质多样而价格低廉的服务。本文分析了4G发展的可能的几种模式的特点及发展前景,在此基础上对4G通信的发展提出了4种构想,并对中国未来通信发展进行了展望。     

Wireless loops: What are they?

Several loop applications of wireless technology are aimed at reducing the cost of deploying communications services ranging from telephone to wideband video. In these applications, wireless links replace a portion of a wireline loop from a central location (a central office or cable headend) to a subscriber. The replacement of labor-intensive wireline technology by complex mass-produced integrated electronics in wireless transceivers is projected to reduce the overall cost of the resulting loop. These wireless loop applications attempt to provide existing communications services or small modifications to existing communications services. A different interpretation of a wireless loop makes use of low-power digital radio technology to provide the last thousand feet or so of a loop. Low-power low-complexity wireless loop technology in small base units can be integrated with network intelligence to provide the fixed-infrastructure network needed to support economical personal communications services (PCS) to small, lightweight, low-power personal voice and/or data communicators. Low-complexity communicators can provide many hours of “talk time” or data transmission time and perhaps several days of standby time from small batteries (≤ 1.5 oz). Because this application of wireless loop technology can reduce the inherent costs in several parts of a wireline loop, it has the potential to provide convenient widespread PCS at less costs than providing telephone services over conventional wireline loops. This low-power wireless loop application does not fit into any existing communications system paradigm. Wireless technology with tetherless access and wide-ranging mobility, e.g., the personal access communications system (PACS), does not fit the accumulated wisdom of the wireline telephony paradigm. It also does not fit the paradigm of existing cellular radio that has sparsely distributed expensive cell sites, and it is not targeted at fixed video services as is wireless cable. Because a significant change in thinking is required in addressing this new low-power low-complexity widespread wireless loop paradigm, its large economic advantages and service benefits have not yet been embraced by many of the existing communications providers, who appear to be more comfortable pursuing the better-known paradigms of video using wireless cable, or of cellular radio in the guise of high-tier PCS, or in the guise of rapid economical deployment of telephone services in developing nations. This paper discusses the inherent economic advantages and service benefits of low-power low-complexity wireless loop technology integrated with network intelligence aimed at providing economical low-tier PCS to everyone.     

Coexistence and interworking between UMTS and UWB: a performance evaluation of a UMTS/UWB interoperability platform

Ultra wideband (UWB) radio technology is nowadays one of the most promising technologies for medium-short range communications. It has a wide range of applications including high data rate systems and low data rate systems with location and tracking. The interoperation of UWB with Wide Area Networks (WAN) technologies is very interesting in order to extend the scope of UWB applications, but harmless coexistence between them must be assured. Extensive research is being focused to the development of efficient mitigation techniques and the collaboration between both radio services is an interesting solution when UWB is collocated in the same device with other radio technology. In this paper a UMTS/UWB interworking platform is presented, which allows remote monitoring of a UWB body area network for medical applications. The coexistence between UMTS and UWB is evaluated and cooperative mitigation techniques are proposed and implemented in the platform.     

B3G移动通信系统的研究框架

和3G移动通信系统的业务相比，B3G移动通信系统的业务具有显著的特征，如：分组数据业务占优、业务类型显著增多、业务规模显著增大、传输峰值速率显著提高、业务传输速率的动态范围显著智大、业务在空间和日寸间上的分布差异显著增大、业务请求常发生在高速移动的交通工具中等。为了适应B3G系统的业务需求，B3G系统必须在网络结构、空中接口方案、无线资源分配策略，乃至电波频段和射频技术等方面都有全新的改变。因此，B3G移动通信系统的研究应当重点包括以下几个方面的内容：广义蜂窝通信网络理论与构造方法、充分利用空间资源的MIMO无线通信传输理论、无线通信资源与新型空中接口适配方法、新型迭代式编码调制与自适应链路技术、新型天线与射频技术等。     

Emerging mobile and personal communication systems

The market demand for wireless communications has been demonstrated by the rapid growth of different second-generation wireless technologies that are optimized for particular applications and environments. Obvious examples include: digital cellular systems like GSM, ADC, PDC,and DCS1800 for widespread vehicular and pedestrian services, and cordless telecommunication systems based on CT2, DECT, and PHS standards for residential, business, and public cordless access applications. Efforts are also underway to consolidate the various radio environments and applications under a single standard for third generation wireless, i.e., FPLMTS. In the area of personal mobility, with the recent availability of “personal” numbers in various countries (e.g., 500 numbers in the United States), many fixed network operators are starting to offer such personal mobility services as “personal number service” and “number portability”. These services represent initial stages of full personal mobility that will be provided by UPT in both wireline as well as wireless environments. The expected heavy demand for PCS in the United States and the underlying market/regulatory forces are driving the standardization and business activity. A number of air interface standards for the 1900 MHZ PCS band are being considered, which are based on TDMA, CDMA, and FDMA technologies singly or in combination. Many are variations of existing digital cellular and cordless telecommunications technologies. PCS networking standards are also being developed; both for standalone systems and for systems that will utilize public switched network capabilities     

The wireless art and the wired force of subscriber access

Different technologies for subscriber access are put side by side. Starting from the various transmission media characteristics of all systems, the well-known twisted pair lines with their corresponding digital subscriber line services are evaluated against wireless local loops, communications over ubiquitous power lines, high-bandwidth cable modems, and mobile radio. Each technology has its advantages and disadvantages. The different technologies will find their fields of applications. Most networks will have to provide a mixture of solutions for individual subscribers and customer segments to meet their boundary conditions. As a result, the future of subscriber access is a hybrid solution     

Wireless Mesh Technology and Network

Wireless Mesh Network (WMN) has been actively researched and developed as a new network technology to support broadband high- speed multimedia services . This paper discusses WMN technology and applications , and introduces the basic technologies , typical applications and current development of the WMN. With the future development of wireless distribution technology and network, wireless Mesh technology and network will become the key networking technology and architecture of wireless mobile communications , and will be widely used in various wireless networks with more important roles .     

5G无线通信网络物理层关键技术

信息社会日益增长的需求,促使着无线通信技术的不断发展。计划于2020年进入商业运营的5G无线通信技术,尚在探索和研究阶段。从无线通信的发展历程出发,介绍了当前国内外的无线通信发展的最新趋势,然后从频谱资源紧缺、系统容量亟需提高的角度,着重介绍了两个关键的物理层技术——毫米波通信技术和大规模MIMO技术,以应对未来无线通信的发展要求。此外,还概括性地介绍了5G无线通信系统的应用场景以及未来的发展趋势。     

The adaptive multirate wideband speech codec: system characteristics, quality advances, and deployment strategies

Wideband speech is the major differentiation and attraction of third-generation network services in both the circuit and packet switched domain. Increased audio bandwidth introduces a significant leap in perceived quality of service compared to currently utilized narrowband telephony in second-generation mobile communications and the PSTN. The adaptive multirate wideband (AMR-WB) speech codec is the service enabler for improved user experience. It is an established 3GPP and ITU-T wideband speech codec standard and represents the state-of-the-art in speech quality as well as robustness in error prone radio channels. It is also the first codec algorithm standardized for wideband speech for mobile communications.     

Advanced cellular Internet service (ACIS)

The public's desire for mobile communications and computing, as evidenced by the popularity of cellular phones and laptop computers combined with the explosive demand for Internet access suggest a very promising future for wireless data services. The key to realizing this potential is the development and deployment of high-performance radio systems. In this article we describe a basic service concept, advanced cellular Internet service (ACIS), and the technologies for achieving reliable high-speed transmission to wide-area mobile and portable cellular subscribers with very high spectrum efficiency. Such a wireless service, optimized to meet the needs of a client-server model for information retrieval and Web browsing, and combined with evolutionary enhancements in second-generation technologies, can provide an attractive option for third-generation systems. The radio link design combines OFDM with transmit and receive antenna diversity and Reed-Solomon coding to overcome the link budget and dispersive fading limitations of the cellular mobile radio environment. For access, a dynamic packet assignment algorithm is proposed which combines rapid interference measurements, priority ordering, and a staggered frame assignment schedule to provide spectrum efficiencies of two-to-four times existing approaches     

Enhancing IP service provision over heterogeneous wirelessnetworks: a path toward 4G

Second-generation mobile radio systems have been deployed successfully worldwide and have evolved to higher data rates and services. Third-generation mobile radio systems are currently starting to be developed in different regions of the world. Today, the open question is how the third-generation systems will evolve. It is very likely that fourth-generation systems will not be a single standardized air interface, but a set of different technologies and standards. In particular, wireless LAN/wireless PAN type systems are designed for high/medium-data-rate access, low range, and, in general, low mobility. They are applicable to corporate networks and public access as a complement to cellular mobile radio systems for hot spot applications such as airports, hotels, and campuses. In this specific WLAN/WPAN framework and to guarantee an agreed QoS provision over such infrastructures, we propose a solution based on the wireless adaptation layer approach. In particular, aspects related to wireless link impairments and traffic requirements are approached by the implementation of configurable, modular software that is adapted to the specific conditions and needs of the particular wireless infrastructures     

Mobile and wireless Internet services: putting the pieces together

There are a variety of emerging technologies and protocol enhancements designed to extend Internet services to mobile users, including operation over more dynamic, heterogeneous wireless interconnections. Many different approaches and protocols have been proposed, and there are even multiple standardization efforts within the Internet Engineering Task Force that address portions of the overall goal. This article highlights some of the emerging technology efforts and provides insight into how some of these pieces may fit together to realize seamless Internet services for users on the move or in application spaces with little to no preexisting communications infrastructure     

下一代无线通信概念和技术

下一代无线通信(NextG:Next-generationwireless)的主流是随时随地的无线通信系统和无缝的高质量无线业务。概述了随时随地的无线通信和业务发展情况,并且介绍了为下一代无线通信的发展提供基础的关键技术。     

Guest editorial. Introduction to the special section: 4G Health--the long-term evolution of m-Health

In the last decade, the seminal term and concept of "m-health" were first defined and introduced in this transactions as "mobile computing, medical sensor, and communications technologies for healthcare." Since that special section, the m-health concept has become one of the key technological domains that reflected the key advances in remote healthcare and e-health systems. The m-health is currently bringing together major academic research and industry disciplines worldwide to achieve innovative solutions in the areas of healthcare delivery and technology sectors. From the wireless communications perspective, the current decade is expected to bring the introduction of new wireless standards and network systems with true mobile broadband and fast internet access healthcare services. These will be developed around what is currently called the fourth-generation (4G) mobile communication systems. In this editorial paper, we will introduce the new and novel concept of 4G health that represents the long-term evolution of m-health since the introduction of the concept in 2004. The special section also presents a snapshot of the recent advances in these areas and addresses some of the challenges and future implementation issues from the evolved m-health perspective. It will also present some of the concepts that can go beyond the traditional "m-health ecosystem" of the existing systems. The contributions presented in this special section represent some of these developments and illustrate the multidisciplinary nature of this important and emerging healthcare delivery concept.