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     

SATELLITE-ENHANCED PERSONAL COMMUNICATIONS EXPERIMENTS

Users of future generation wireless information services will have diverse needs for voice, data, and potentially even video communications in a wide variety of circumstances. For users in dense, inner-city areas, low power personal communications services (PCS) technology should be ideal. Vehicular-based users travelling at high speeds will need high-power cellular technology. For users in remote or inaccessible locations, or for applications that are broadcast over a wide geographic area, a satellite technology would be the best choice. Packet data networks provide an excellent solution for users requiring occasional small messages, whereas circuit switched networks provide more economical solutions for larger messages. To provide ubiquitous personal communications service, it is necessary to capitalize on the strength of each wireless technology and network to create one seamless internetwork including both current and future wired and wireless networks. As an initial step in exploring the opportunities afforded by the merging of satellite and terrestrial networks, Bellcore and JPL conducted several experiments. These experiments utilized Bellcore's experimental personal communications system (including several messaging applications with adaptations to wireless networks), NASA's advanced communications technology satellite (ACTS), JPL's ACTS mobile terminal, and various commercial data networks (such as the wireline Internet and the RAM wireless packet data network). Looking at loss of bits, packets and higher layer blocks (over the satellite-terrestrial internetworks with mobile and stationary users under various conditions) our initial results indicate that the communication channel can vary dramatically, even within a single network. We show that these conditions necessitate powerful and adaptive protocols if we are to achieve a seamless internetworking of satellite and terrestrial networks.     

Wireless mobile communications at the start of the 21st century

At the start of the 21st century, the wireless mobile markets are witnessing unprecedented growth fueled by an information explosion and a technology revolution. In the radio frequency arena, the trend is to move from narrowband to wideband with a family of standards tailored to a variety of application needs. Many enabling technologies including wideband code-division multiple access, software-defined radio, intelligent antennas, and digital processing devices are greatly improving the spectral efficiency of third-generation systems. In the mobile network area, the trend is to move from traditional circuit-switched systems to packet-switched programmable networks that integrate both voice and packet services, and eventually evolve toward an all-IP network. Furthermore, accompanied by wireless mobile location technology, wireless mobile Internet is expected to revolutionize the services that can be provided to consumers in the right place and at the right time. Wireless mobile communications may not only complement the well established wireline network; it may also become a serious competitor in years to come. We review the history of the wireless mobile communications, examine the current progress in standards and technologies, and discuss possible trends for wireless mobile solutions     

Universal personal communications: Emergence of a paradigm shift in the communications industry

It is postulated that today we are in the midst of a major paradigm shift in the communications industry. The essence of this paradigm shift is a transition from today's universal telephone service which has been perfected over the past 100 years, to a future communication service environment, referred to as universal personal communication. Under this new paradigm, communications will be person based in contrast to the predominantly location-based communication environment of today. Societal trends, evolving global standards for communication, regulatory policies, and emergent technologies are seen as the forces driving such a transition. Universal personal communications will be characterized by flexible access to universal services permittingmore enduser control which will result in personalization and customization of such services. Furthermore, the centralized intelligence focus of today's communication networks needs to evolve toward a focus where network intelligence can be migrated to the periphery of the core transport network. The viability of universal personal communication will be critically dependent upon how well it addresses the end customer value proposition. Two key elements of this proposition are transparency of mobility and personalization of service environments. A zonal service environment model which classifies and characterizes these various service environments in terms of common communication parameters is proposed. This model is built around hierarchical structures for both cellular and digital wireless transmission, and can be viewed as critical towards the realization of transparent mobility management and personalization of services.     

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     

Design considerations of satellite-based vehicular broadband networks

Convergence between wireless networks is the main trend in current and future wireless communications. The distinct advantage of satellite and terrestrial network integration is the possibility to provide ubiquitous multimedia services in vehicles at any location. The key design considerations of mobile broadband satellite access technologies are given in this article. After presenting the conceptual models of a system and services, the design issues of satellite network synchronization and burst demodulation are described. The design considerations of medium access control, resource management, capacity, and buffer controls for internetworking are given. Also, the active antenna issues are provided along with a sample design.     

Voice access of global information for broad-band wireless:technologies of today and challenges of tomorrow

The rapid development of the Internet and the World Wide Web has created a global network that will soon become a physical embodiment of the entire human knowledge and a complete integration of the global information activities. The traditional approach to access the network is through a computer physically tied to the network. As broad-band wireless takes off, the traditional tethered approach will gradually become obsolete. It is believed that one of the most natural and user-friendly approached for accessing the network will be via human voice, and the integration of spoken language processing technologies with broad-band wireless technologies will be a key to the evolution of a broad-band wireless information community. This paper offers a vision of the above concept. Technical considerations and some typical example applications of accessing the information and services using voice in a broad-band wireless environment are discussed. Fundamentals of spoken language processing technologies that are crucial in such a broad-band wireless environment are briefly reviewed. Technical challenges caused by the unique nature of wireless mobile communications are also presented along with some possible solutions     

Issues in integrating cellular networks WLANs, AND MANETs: a futuristic heterogeneous wireless network

The popularity of wireless communication systems can be seen almost everywhere in the form of cellular networks, WLANs, and WPANs. In addition, small portable devices have been increasingly equipped with multiple communication interfaces building a heterogeneous environment in terms of access technologies. The desired ubiquitous computing environment of the future has to exploit this multitude of connectivity alternatives resulting from diverse wireless communication systems and different access technologies to provide useful services with guaranteed quality to users. Many new applications require a ubiquitous computing environment capable of accessing information from different portable devices at any time and everywhere. This has motivated researchers to integrate various wireless platforms such as cellular networks, WLANs, and MANETs. Integration of different technologies with different capabilities and functionalities is an extremely complex task and involves issues at all layers of the protocol stack. This article envisions an architecture for state-of-the-art heterogeneous multihop networks, and identifies research issues that need to be addressed for successful integration of heterogeneous technologies for the next generation of wireless and mobile networks.     

Applications of voice processing to telecommunications

The ways in which people communicate are changing rapidly. The options are many and diverse, ranging from voice calls over wireless networks, to video calls over the conventional wired network, ISDN video, FAX, e-mail, voice mail, beeper services, data services, audio teleconferencing, video teleconferencing, and so-called scribble phone service (transmission of arbitrary handwritten input). This revolution in communications is being fueled by several sources, including the availability of low-cost, low-power, computation in both DSP and RISC chips, larger and cheaper memory chips, improved algorithms for communications (e.g., modems, signaling) and signal processing, and finally the creation of world-wide standards for transmission, signal compression, and communication protocols. The broad goal of the communications revolution is to provide seamless and high-quality communications between people (or groups of people), anywhere, anytime, and at a reasonable price. Although there are many technologies that form the bases for the communications environment of the twenty-first century, one of the key technologies for making the vision a reality is voice processing. In this paper we attempt to show, by example, how voice processing has been applied to specific problems in telecommunications, and how it will grow to become an even more essential component of the communications systems of the twenty-first century     

Using PARLAY APIs Over a SIP System in a Distributed Service Platform for Carrier Grade Multimedia Services

The implementation of new mobile communication technologies developed in the third generation partnership project (3GPP) will allow to access the Internet not only from a PC but also via mobile phones, palmtops and other devices. New applications will emerge, combining several basic services like voice telephony, e-mail, voice over IP, mobility or web-browsing, and thus wiping out the borders between the fixed telephone network, mobile radio and the Internet. Offering those value-added services will be the key factor for success of network and service providers in an increasingly competitive market. In 3GPP's service framework the use of the Parlay APIs is proposed that allow application development by third parties in order to speed up service creation and deployment. 3GPP has also adopted SIP for session control of multimedia communications in an IP network. This article proposes a mapping of SIP functionality to Parlay services and describes a prototype implementation using the SIP Servlet API. Furthermore, an architecture of a Service Platform is presented that offers a framework for the creation, execution and management of carrier grade multimedia services in heterogeneous networks.     

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     

移动泛在网络的发展趋势

随着无线接入技术的快速发展,通信网络的异构性特征变得更加突出,如何有效地实现不同网络间的互联互通以及获取所需的各类服务,并构建融合各网络异构性的移动泛在网络成为业界关注的重点。下一代移动网络(NGMN)项目综合考虑业务、终端和网络各方面的因素,是运营商主导的近期需求愿景,而移动泛在业务环境(MUSE)是学术界的学者们对于未来移动异构泛在网络的理想化的规划和设计,更着眼于远期的融合。未来的移动通信网络将逐渐向一个综合的网络体系平滑演进,为泛在移动宽带服务提供一个全新的平台。     

Broadband fixed wireless access as a key component of the futureintegrated communications environment

It is an exciting time for broadband fixed wireless with key developments in frequency bands from 1 to 60 GHz and a range of new technologies being developed. While working on these new technologies, it is easy to forget that fixed wireless access will form part of an integrated communications environment of the future where users will have one communications device working in the home, at the office, and outdoors. This article predicts the communications environment of the next 20 years and looks at the role of fixed access within that environment. This involves assessing how fixed access systems will interface and integrate with in-home wireless networks, how their architecture will enable multiservice operators to utilize the same core network across a range of different access technologies, and how they will act as a channel to carry mobile traffic originating within the building. Based on the requirements this vision and architecture implies, this article critically assesses the different fixed wireless technologies available to date and compares their capabilities to provide future-proof broadband fixed wireless platforms     

Transmission quality of north American cellular, personalcommunications, and public switched telephone networks

Future long distance, and especially international calls, will involve an increasing number of multilink circuits of cellular, personal communications, mobile satellite, and public switched telephone network (PSTN) type of connections incorporating a variety of speech coding devices. In particular, the rapid growth of cellular communications has highlighted the need to characterize the quality of switched networks when cellular terminals are attached at their termination nodes. At the same time, the nonlinear nature of low-rate parametric speech coding has rendered questionable analytical methods for estimating end-to-end voice quality of interconnected telecommunications networks. Instead, quantification of transmission performance appears to require direct subjective evaluation of the pertinent conditions of interest. In this paper the quality of interconnected North American digital cellular and future microcellular terminals with 16 kbit/s and 32 kbit/s DCME/PCME-based switched and private telephone networks is quantified. From these assessments it can be concluded that cellular networks employing the TIA IS-54 8 kbits/s VSELP algorithm may meet the end-to-end transmission planning criteria when interconnected with the switched network     

无线数字家庭网络泛在接入技术

数字家庭网络是通信领域的一个重要分支，近年来发展非常迅速。基于电信网络的数字家庭网络体系结构在中国已经标准化，但就接入方式而言，只是定义了可以使用无线方式，如何组建无线数字家庭网络是未来研究的重点。文章提出了无线数字家庭网络泛在接入概念，给出了无线泛在接入网络体系结构，并就其中的关键技术进行了探讨，包括感知无线电、无线网状网（Mesh）网络理论、通用接入点链路转换机制、业务的QoS保障机制以及电磁兼容和异构系统共存机制等。     

Personal communications networks: Competition,convergence, and cooperation

The increasing mobility of the workforce, combined with the rapid convergence of computer, communications, and consumer electronics technologies, has spurred the development of numerous new wireless communications products and services. Accelerating competition has vastly increased the number of technological options available to consumers to meet their needs for personal communications. Unfortunately, this increase in options has been accompanied by increased and undesirable complexities. Even for simple wireless voice communications, the average customer has to deal with multiple telephone numbers, roaming codes, and confusing pricing arrangement. Exacerbating the inherent difficulties in using individual wireless technologies is the lack of interoperability among these services. Existing wireline networks, with their ubiquity, seamless operations, and ease of use, have provided clear benchmarks for satisfying customers' basic personal communications needs. There are considerable potential benefits to be realized, in terms of increased investment efficiencies, reduced time to market and the ability to meet the individual needs of consumers more closely, through the increase in the level of cooperation among competing services and technologies.     

Progress Towards User Access Arrangements in Integrated Services Digital Networks

This paper deals with arrangements for local access to emerging Integrated Services Digital Networks (ISDN's). The ISDN concept is here introduced as the focal point for the ongoing international activity on multiservice digital networks. ISDN's are conceived as networks which have evolved from the basic digital telephone networks and they will provide end-to-end digital connectivity to support a wide range of services including voice, data, sound, and video applications. After giving a general outline of the evoving ISDN network scenarios for digital communications, the paper reviews the international trends on user access arrangements in terms of 1) user equipment and interface configurations, 2) access channel structures and information transfer capabilities, 3) local distribution plant configurations (with emphasis on the copper plant), and 4) access protocols.     

High-bandwidth interface for multimedia communications over fixedwireless systems

Over the past two decades, cable television has largely supplanted over-the-air broadcast as a TV distribution medium. Several years ago, enterprising companies concluded that they could leverage the extremely wide bandwidth of cable TV systems required to deliver broadcast-quality television as a high-speed conduit for broadband data communications. This led to the birth of the cable modem. Early cable-modem equipment was vendor proprietary, so interoperability between different vendors' products was largely nonexistent. To promote interoperability, Cable Labs (the cable TV industry research arm) developed the Data Over Cable Service Interface Specification (DOCSIS 1.0), an IP-centric, point-to-multipoint standard that quickly replaced the proprietary solutions that preceded it. DOCSIS has now become the accepted cable standard. The newly released DOCSIS 1.1 is destined to play an important role in the delivery of high-quality multimedia across fixed wireless communications networks. With this approach, we can take advantage of all the DOCSIS technology modules that exist in the market today, allowing the wireless platform to migrate toward emerging services such as Internet protocol multicasting and voice over IP (VoIP). We describe the state of current technologies that have made fixed-wireless access a viable and compelling choice. We also discuss some emerging technologies that will bring exciting new fixed-wireless services and capabilities into homes and small businesses in the near future     

An outlook on the evolution of mobile terminals: from monolithic to modular multiradio, multiapplication platforms

Terminals, including traditional cellular phones, have historically been optimized for a small number of services over a specific network. With the convergence of consumer electronics and Internet-based services, voice and video are now being offered on a variety of access networks, and many functions are being combined into single devices. In addition to new sophisticated audio/video coding and graphics capabilities, there is a growing demand for cheap and ubiquitous broadband wireless Internet access. This demand is driving the need for multiradio platforms that include new licensed and unlicensed air interface technologies, such as WLAN, UWB and Wimax. The proliferation of new applications and wireless standards has created the need for a dramatic change in the portable/mobile terminal architecture. This paper presents an overview of the evolution of mobile terminal architectures, from monolithic to flexible, modular, and capable of meeting the increasing demand for an ever larger number of features at the right cost and time to market.     

Voice communications over zigbee networks

This article provides an overview of ZigBee-enabled wireless networks and discusses the feasibility of supporting voice communications over ZigBee networks. We begin by providing an overview of the ZigBee technology followed by an evaluation of voice quality and performance over such an impoverished wireless channel. Two types of voice communications, namely full-duplex voice over IP (VoIP) and half-duplex push-to-talk (PTT) are considered. Voice quality of VoIP is measured using the R-factor [1] (a well known objective speech quality metric). The quality of PTT, however, is evaluated based on packet-loss rate, delay, and jitter. The simulation results demonstrate that a low-power, low-rate wireless sensor network can support a limited range of voice services.