软件无线电技术及其在蜂窝移动通信系统中的应用研究

软件无线电技术是近年来出现的新的无线通信设计思想与框架。是无线通信领域的一项突破性关键技术。本文详细了软件无线电的概念、系统结构、基本特征,在典型软件无线电体系基础上,描述了应用该设想的蜂窝区基站功能。同时结合关键技术,展望了软件无线电的发展趋势。     

无线通信的新发展:从软件无线电到认知无线电

频谱资源的有效利用成为无线通信的一个重要问题和制约无线通信发展的新瓶颈。认知无线电(Cognitive Radio,CR)技术进一步扩展了软件无线电(SDR)的功能,成为解决频谱资源匮乏问题的有效方法。基于认知无线电在无线通信中的重要作用,介绍了认知无线电的概念、模型、性能评估,总结了认知无线电的基本特征,分析了传统无线电、软件无线电和认知无线电三者之间的关系,提出了认知无线电研究需要解决的关键技术,可为相关领域的技术人员提供参考。     

认知无线电的发展与应用

频谱资源的有效利用成为无线通信的一个重要问题和制约无线通信发展的新瓶颈.认知无线电(Cognitive Radio, CR)技术进一步扩展了软件无线电(SDR)的功能,成为解决频谱资源匮乏问题的有效方法.基于认知无线电在无线通信中的重要作用,介绍了认知无线电的概念,总结了认知无线电的基本特征,分析了传统无线电、软件无线电和认知无线电三者之间的关系,概述了认知无线电在民用和军用领域的应用情况,讨论了认知无线电涉及的关键技术,指出了开展认知无线电技术研究的重要意义.     

软件无线电技术在调频发射机设计中的应用探讨

本文从软件无线电的基本概念以及软件无线电运行技术入手,探讨软件无线电技术在无线通信领域的技术运用,尤其是在调频发射机设计中的相关运用,以此深入了解、分析软件无线电技术在现代通信的应用.     

基于软件无线电的OFDM系统设计与实现

为了构建一个适应性强,复用程度高,易于维护、升级的无线电系统平台。提出采用软件无线电将通信系统软件模块化的思想设计OFDM无线通信系统。给出了采用软件无线电思想构建无线通信系统的技术方案,其中重点介绍系统软件波形的开发方法,并具体给出波形算法开发流程,对于开发一个开放式的通信系统具有指导作用。     

从软件无线电到认知无线电的无线通信发展现状

本文归纳了从软件无线电到认知无线电功能的演进。认知无线电又是在软件无线电的基础上提出的智能化的无线通信技术,它着力解决频谱资源的有效利用问题：认知无线电概念的提出将对现行的频谱管理体制提出挑战,并给无线通信带来新的发展空间。在此基础上探讨了认知无线电技术未来发展值得关注的热点问题。     

采用软件无线电结构的蜂窝移动通信系统

软件无线电技术是近年来出现的新的无线通信设计思想与框架。本文在典型软件无线电体系基础上，描述了应用该设想的蜂窝区基站功能。同时结合关键技术，展望了软件无线电的发展趋势。     

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。     

软件无线电技术

论述了软件无线电的概念、特点和出现的必然性,以及软件无线电的组成结构,讨论了软件无线电中的关键技术和对它的应用,认为软件无线电是实现无线通信的一种新的体系结构,摆脱了面向用途的设计思想,具有较好的灵活性和通用性。     

软件无线电SDR的关键技术研究

作为当今无线通信领域的新技术--软件无线电SDR(Software-Defined Radio)应用前景十分广阔,正引起国内外越来越多的关注.本文介绍了软件无线电的概念、发展与现状,分析了软件无线电的关键技术及对策,并对当前软件无线电应用所面临的问题作了探讨.     

Instruction Set Extensions for Matrix Decompositions on Software Defined Radio Architectures

Emerging wireless applications consistently demand higher data rates. Unfortunately, it is challenging to achieve high data rates within the limited amount of available frequency spectrum. Hence, enhanced spectral efficiency and link reliability within the available frequency spectrum are of the utmost importance in current and next generation wireless protocols. To attain high spectral efficiency and link reliability, wireless protocols employ increasingly complex 2-dimensional techniques that involve computationally-intensive matrix operations. Multiple-Input Multiple-Output (MIMO) communication is an example of a promising technique employed by wireless protocols to deliver higher data rates at the cost of increased algorithmic complexity. Application Specific Integrated Circuits (ASICs) have traditionally been used to implement compute-intensive wireless protocols. The wireless industry has been gradually moving towards an alternative programmable platform called Software Defined Radio (SDR) due to its significant benefits, such as reduced development costs, and accelerated time-to-market. The computationally-intensive matrix operations used in current and next generation wireless protocols are extremely expensive to implement in SDR platforms with conventional Digital Signal Processor (DSP) instruction sets. Hence there is a need for novel instructions, hardware designs and algorithm enhancements to enable higher spectral efficiency on SDR platforms. In this paper, we propose Single Instruction Multiple Data (SIMD) CoOrdinate Rotation DIgital Computer (CORDIC) instruction set extensions with CORDIC hardware support to speedup computationally-intensive matrix decomposition algorithms. The CORDIC instruction set extensions have been implemented on the Sandbridge Sandblaster SB3000 SDR platform and evaluated on conventional algorithms used for decomposing a closed loop 4-by-4 Worldwide Interoperability for Microwave Access (WiMAX) MIMO channel into independent Single-Input Single-Output (SISO) channels. Our experimental results on the closed-loop MIMO channel decomposition using CORDIC instructions demonstrate more than 6x speedup over a Sandblaster baseline implementation that uses state-of-the-art SIMD DSP instructions. The CORDIC instructions also provide similar numerical accuracy when compared to the baseline implementation. The techniques we propose in this paper are also applicable to other SDR and embedded processor architectures.     

Two Step Timing Synchronization Scheme for OFDM Signal in General Purpose Processor Based Software Defined Radio Receiver

Software defined radio (SDR) is a technology that allows a single terminal to support various kinds of wireless systems by changing its software to reconfigure itself. A general purpose processor (GPP) based SDR receiver platform named Sora has been recently developed by Microsoft. In the GPP based SDR receiver, timing synchronization of an OFDM signal consumes a significant amount of computational resources in the GPP. In this paper, a timing synchronization scheme which uses delayed correlation and matched filtering for the GPP based SDR platform is evaluated. The two stage timing synchronization scheme reduces the computational complexity by limiting the timing range of matched filtering. The proposed scheme reduces the amount of data transmission between the memory and the GPP of the SDR platform. It is shown through an experiment that the proposed scheme reduces the number of cycles for timing synchronization by up to 30 %.     

Analysis and implementation of six-port software-defined radio receiver platform

With recent advances in semiconductor processing technology and the development of reconfigurable devices, high bit-rate software-defined radio (SDR) has become practical for commercial applications. This paper proposes an SDR receiver platform based on a new substrate integrated waveguide six-port structure. This SDR receiver platform operates from 22 to 26 GHz and it is designed to be robust, low cost, and suitable for different communication schemes. In this study, the receiver is demonstrated to support quadrature phase-shift keying and 16 quadrature amplitude modulation schemes. System-level simulation is made and prototype circuits are fabricated to evaluate the system performance. It is found that the combination of SDR and six-port technology can provide a great flexibility in system configuration, a significant reduction in system development cost, and also a high potential for software reuse. The proposed receiver shows a possible application of universal direct demodulator for future SDR terminals in various wireless communication systems.     

一种低功耗软件无线电信号处理平台

介绍一种应用于软件无线电的数字信号处理平台,通过对平台设计架构、硬件实现方案及软件可配置功能的阐述,提出了GMSK和CPM两种无线通信波形软件实现方案。该平台采用OMAP+FPGA的架构,具有通用性好、扩展性强等特点,适合于高性能、低功耗的应用场合,可广泛应用于在无线通信、导航定位、图像处理等数字信号处理领域。     

软件无线电关键技术分析

作为当今无线通信领域的新技术——软件无线电SDR（Soflware—Defined Radio）应用前景十分广阔,正引起国内外越来越多的关注。本文介绍了软件无线电的概忿特点及体系结构,分析了软件无线电的关键技术,阐述了软件无线电的发展应用前景。     

基于分层模型的终端调制解调重构研究

相比于传统单一接入功能终端以及多模终端,异构无线网络中的重构终端基于一个通用可重配置的软件无线电（SDR）平台实现不同接入功能,有效减少资源的利用。基于SDR分层设计思想,对终端调制解调重构实现建模进行研究。通过对四相相移键控信号（QPSK）和16QAM两种典型调制方式的调制解调重构仿真,并与传统终端进行比较,验证了所构建的终端调制解调重构模型的正确性,为终端重构实现技术的研究打下了基础。     

软件无线电关键技术分析

作为当今无线通信领域的新技术——软件无线电SDR(Software-Defined Radio)应用前景十分广阔,正引起国内外越来越多的关注.本文介绍了软件无线电的概念、特点及体系结构,分析了软件无线电的关键技术,阐述了软件无线电的发展应用前景.     

Research and developments of software-defined radio technologies inJapan

Software-defined radio technologies are attractive for future mobile communication systems because of reconfigurable and multimode operation capabilities. The reconfigurable feature is useful for enhancing functions of equipment without replacing hardware. Multimode operation is essential for future wireless terminals because a number of wireless communication standards will still coexist. Research efforts on SDR have become very active in Japan, and various kinds of SDR prototypes have been developed. This article introduces the trends of Japanese wireless communication systems and the role of SDR technologies for the future wireless systems. R&D activities for the SDR in the field of academia and industry are also presented including examples of SDR prototypes     

Reconfigurable channel filtering and digital down conversion in optimal CSD space for software defined radio

Software defined radio (SDR) is a platform for using the same hardware to support multiple wireless communication standards. The channelizer in the SDR is used to separate the channels from the wideband signal. The features required for using the same hardware to switch between different standards are reconfigurability and low complexity. To achieve this, we use a variable bandwidth filter (VBF) with facility for the reduction and enhancement of the bandwidth, without changing the filter coefficients. This paper proposes an optimal and multiplier-less implementation of a baseband channel filter for supporting the bandwidth requirements of various wireless communication standards. This paper also discusses the concept for using it as a multi-band SDR channelizer for the direct conversion of signals from a wideband input to the baseband signal without using an intermediate stage. Frequency response masking (FRM) filter with continuous coefficients is designed and modified harmony search algorithm is used for finding the optimal canonic signed digit representation for the multiplier-less implementation. This reduces the complexity and power consumption. The VBF with the optimized FRM filter is evaluated for the selectable bandwidths starting from 1.25 to 8 MHz, which covers the bandwidth requirements of a wide range of wireless communication standards.     

Security Optimization of DF Relay Selection Strategy Under Outdated Scenarios

The spectrum has always been an essential resource of information for wireless communications. With the continued growth of Internet of things (IoT) and 5G, there is a demand to understand how the spectrum is used. One of the challenges of deploying IoT applications is the crowded spectrum in the unlicensed industrial scientific medical bands leading to rising coexistence problems between different wireless protocols. To overcome this congestion, hardware tools supporting spectrum sensing can be used to manage the spectrum more efficiently. In this context, this work presents a prototype that measures a set wireless metrics on raw wireless signals acquired with software defined radio (SDR) technology. This prototype aims to provide mechanisms to sense and monitor spectrum usage that can mitigate one of the issues that IoT faces, the interference being produced by having different technologies using at the same frequency channels. The prototype features configurable radio frequency parameter and programmable periodical tasks execution. It displays wireless metrics such as signal to noise ratio, cumulative density function and power spectral density. This prototype uses web and SDR technologies, highlighting the idea and feasibility of combining these two technologies. In addition, it demonstrates the possibility to obtain wireless metrics with a low-cost hardware based on open source tools in a platform where interaction, debugging and maintaining becomes intuitive and easier. Results of measurements of LoRa protocol signals are presented to demonstrate the capabilities of the prototype.