Design and performance analysis of an advanced, narrowbandintegrated voice/data mobile radio system

Private land mobile communications have experienced significant demand for increased capacity and for new services, but congestion within the currently allocated 450 and 800 MHz bands has severely limited the capability of present generation systems to meet this demand. This paper proposes a narrowband integrated voice/data mobile radio system which triples current voice traffic capacity and simultaneously provides capacity for mobile data communications such as mobile data terminals, automatic vehicle location, and mobile facsimile by utilizing the silence gaps inherent in speech. The system is designed to fit within the narrowband 25 kHz channels in the 450 and 800 MHz frequency bands, and thus the system can replace existing private land mobile radio systems with minimum impact. The centerpiece of the system design is an evolutionary multiplexing and access control technique known as Packetized Data, Voice Dedicated (PDVD) Burst Switching which allows transmission of data within the silence gaps inherent in speech. Simulation results for various voice and data traffic loads show the flexibility and efficiency of the proposed narrowband integrated voice/data mobile radio system     

Universal Digital Portable Communications: A System Perspective

In our highly mobile society, the provision of voice and data communications to a person away from his/her wireline telephone has become a major communications frontier. The early penetration of this frontier has been based on very limited portable communications approaches, e.g., cordless telephones, mobile radio telephones, and radio paging. Each of these approaches only partially satisfies portable communications needs. This paper describes an approach to providing universal digital portable communications integrated into telephone networks. A system configuration employing time-division multiple-access radio link architecture and frequency reuse is described. Issues affecting radio link transmission rates and radio system coverage are discussed. Characteristics and parameters of a possible system to supplement the wire (or fiber) loop are indicated.     

A radio system proposal for widespread low-power tetherlesscommunications

It is suggested that low-power digital radio as an access technology could be integrated into a local exchange network to provide a ubiquitous personal communications network (PCN). High-quality tetherless communications services that could be provided by such an exchange-network-based PCN are described. A possible low-power exchange access digital radio system for providing these exchange-network based PCS services is discussed. The radio system uses a spectrum-efficient time-division multiple-access (TDMA) architecture made possible by advanced digital signal processing techniques. Control of the frequency reuse system is described, and frequency spectrum needs are indicated     

一种新型战术电台的关键技术分析与设计

软件无线电是无线通信领域中重要技术,它为新一代无线通信技术指明了方向,并提供了有力的技术保障。新型战术电台采用软件无线电技术为设计基础,新型战术电台具备宽频段覆盖、多模式多任务支持能力,是美军联合战术无线电系统的主要目标,论文对下一代战术电台的功能目标和主要技术体制进行了研究和分析,并提出了基于高集成度射频前端、组网波形、软件无线电等技术的新型战术电台设计方案。     

The rapidly deployable radio network

The rapidly deployable radio network (RDRN) is an architecture and experimental system to develop and evaluate hardware and software components suitable for implementing mobile, rapidly deployable, and adaptive wireless communications systems. The driving application for the RDRN is the need to quickly establish a communications infrastructure following a natural disaster, during a law enforcement activity, or rapid deployment of military force. The RDRN project incorporates digitally controlled antenna beams, programmable radios, adaptive protocols at the link layer, and mobile node management. This paper describes the architecture for the RDRN and a prototype system built to evaluate key system components     

The DARPA internet protocol suite

THE MILITARY requirement for computer communications between heterogeneous computers on heterogeneous networks has driven the development of a standard suite of protocols to permit such communications to take place in a robust and flexible manner. These protocols support an architecture consisting of multiple packet switched networks interconnected by gateways. The DARPA experimental internet system consists of satellite, terrestrial, radio, and local networks, all interconnected through a system of gateways and a set of common protocols.     

基于SCA的软件无线电SoPC设计

软件通信体系架构为实现具有开放性、标准化、模块化的通用软件无线电平台提供了规范。为了实现无线通信系统的小型化,采用软硬件协同设计的方法构建了基于SCA的软件无线电SoPC系统,该系统实现了波形组件的动态配置和部署,以及硬件组件的部分重构。同时它具有效率高,体积小,功耗低,功能强的优点,具有很好的应用前景。     

A programmable architecture for OFDM-CDMA

Combining multicarrier (OFDM) and CDMA technologies is attractive for future wireless broadband communications and software radio realization. Based on the unified framework known as OFCDMA, we develop a programmable structure for OFDM-CDMA transceivers in spite of three different scenarios to combine OFDM and CDMA. By adjusting system parameters without changing the fundamental hardware and software architecture, various system scenarios can be implemented, which might serve as the foundation to design software radio     

Analysis and design of a frequency-hopped spread-spectrumtransceiver for wireless personal communications

Personal communications services (PCS) require low-power radio technologies. One such transceiver architecture employing frequency-hopped spread-spectrum techniques is presented. System features such as antenna diversity with equal-gain combining and sequential hop combining are incorporated into the transceiver design to achieve robust wireless digital data transmission over fading channels. A direct-conversion architecture from radio frequency (RF) to baseband reduces the overall power consumption by eliminating intermediate frequency (IF) components. High-rate frequency hopping with frequency-shift keying (FSK) modulation is implemented using a direct digital frequency synthesis technique. A multiplierless correlation FSK detector, suitable for direct-conversion receivers, has been designed for quadrature noncoherent detection. Robust acquisition algorithms based on energy detection and pattern matching and tracking architectures using digital phase-locked loops are also described for system synchronization. The proposed transceiver is well-suited for low-power PCS applications and other portable wireless communications     

ATM-based TH-SSMA network for multimedia PCS

Personal communications services (PCS) promise to provide a variety of information exchanges among users with any type of mobility, at any time, in any place, through any available device. To achieve this ambitious goal, two of the major challenges in the system design are: (i) to provide a high-speed wireless subsystem with large capacity and acceptable quality-of-service (QoS) and (ii) to design a network architecture capable of supporting multimedia traffic and various kinds of user mobility. A time-hopping spread-spectrum wireless communication system called ultra-wide bandwidth (UWB) radio is used to provide communications that are low power, high data rate, fade resistant, and relatively shadow free in a dense multipath environment. Receiver-signal processing of UWB radio is described, and performance of such communications systems, in terms of multiple-access capability, is estimated under ideal multiple-access channel conditions. A UWB-signal propagation experiment is performed using the bandwidth in excess of 1 GHz in a typical modern office building in order to characterize the UWB-signal propagation channel. The experimental results demonstrate the feasibility of the UWB radio and its robustness in a dense multipath environment. A ATM network is used as the backbone network due to its high bandwidth, fast switching capability, flexibility, and well-developed infrastructure. To minimize the impact caused by user mobility on the system performance, a hierarchical network-control architecture is postulated. A wireless virtual circuit (WVC) concept is proposed to improve the transmission efficiency and simplify the network control in the wireless subsystem. The key advantage of this network architecture and WVC concept is that the handoff can be done locally most of the time, due to the localized behavior of PCS users     

软件无线电发展综述

软件无线电是实现无线通信的新概念和新体制,是其未来的发展方向。本文首先介绍了软件无线电的思想,以及推动其发展的市场因素和技术因素。其次,介绍了软件无线电的现状和发展方向。     

Compact multidimensional broadband wireless: the convergence of wireless mobile and access

Broadband wireless communications have gained increased interest during the last few years. This has been fuelled by a large demand on high-frequency utilization as well as a large number of users requiring simultaneous high-data-rate access for the applications of wireless mobile Internet and e-commerce. The convergence of wireless mobile and access will be the next storm in wireless communications, which will use a new network architecture to deliver broadband services in a more generic configuration to wireless customers, and support value-added services and emerging interactive multimedia communications. Large bandwidth, guaranteed quality of service, and ease of deployment coupled with the great advancements in semiconductor technologies make this converged wireless system a very attractive solution for broadband service delivery.     

认知无线电技术及其政策影响和市场前景预测

认知无线电是在软件无线电的基础上发展而来的能够自适应外界环境变化的无线通信技术。认知无线电的网络结构有3种类型:集中式,分布式和集中 分布式。它通过频谱自适应技术来实现动态频谱分配,相关技术包括频谱检测技术,信道估计与预测技术、数据传输技术和多天线通信技术。随着认知无线电技术的发展,各国际标准组织和行业联盟纷纷开展相关的研究,并着手制定认知无线电的标准和协议。目前,认知无线电的推广仍面临着政策问题,但其市场需求日益扩大。总而言之,此技术的产业化发展还有很长的路需要走。     

A vision from the future: beyond 3G TDD

This article introduces the visions and developments of Beyond 3G mobile communications in the China TDD Special Work Group. System structure, radio transmission design, radio resource management, and demonstration system implementation are covered. In system structure, the concept of group cell and the architecture of distributed antennas are introduced. The radio link transmission design presented in this article includes the radio frame structure, multiple access scheme, and promising key techniques. Link-level simulations prove the advantages of the design. The radio resource management strategies are introduced to optimize the system performance. The B3G TDD demonstration system being built by the TDD Special Work Group is also shown finally.     

A Study and Design of a Configurable CDMA Communication Platform

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NASA未来的空间C&N体系及关键技术

介绍了NASA空间通信体系工作组(SCAWG)所提出的2005～2030年NASA空间通信与导航体系。该体系包括地基地球、近地中继、月球中继和火星中继4个物理单元,以及叠加在这4个物理单元之上的网络、安全、频谱及导航4个贯穿的公共体系。为实现这一体系,SCAWG提出了未来6大关键的技术领域,包括上行链路组阵、光通信、航天器RF技术、X射线导航、网络技术和可编程通信系统(软件定义无线电)。通过对NASA未来空间通信与导航体系及关键技术领域进行研究,可为未来的空间探测活动及相关技术发展提供参考。     

Indoor radio communications using time-division multiple accesswith cyclical slow frequency hopping and coding

The authors describe and analyze a flexible, robust, multichannel time-division-multiple-access (TDMA) radio communications system that is ideally suited for portable as well as mobile indoor use. It uses noncoherent signaling and incorporates slow cyclical frequency hopping and burst-error-correcting coding to provide low-error communications at aggregate rates of several megabits per second without the need for antenna diversity or adaptive equalization. The system can be implemented in a small building using a centralized architecture or in a large building using a distributed antenna system. The TDMA protocol allows the various users the flexibility of choosing their own desired rates of data communications. Moreover, the capability of using different levels of coding gives the users the option of selecting their own error performance. The ability to combat interference is one of the salient features of this system     

Technical challenges in the globalization of software radio

The software radio has emerged from the third-generation strategy for affordable, ubiquitous, global communications. This article reviews the concepts, architecture, technology challenges, and economics of the continuing productization and globalization of software radio     

多总线结构MHAL路由方法

在分析传统调制解调级硬件抽象层（Modem Hardware Abstract Layer,MHAL）路由方法局限性的基础上,提出了一种多总线结构MHAL路由方法,并详细介绍了该方法的设计实现及验证。基于多总线结构MHAL路由方法在不违反软件通信结构规范的前提下,解决了传统方法不能解决的处理器间多总线路由、处理器多端口路由以及数据包路由转发问题。该技术已在某大型软件无线电系统中得到应用。