软件无线电信道处理的DSP实现

本文重点研究了软件无线电(Software Defined Radio,SDR)中不同信道的处理技术,其技术关键在于构建不同频段的数字滤波器进行不同信道信息的接收处理.在建立软件无线电信道模型的基础上,利用MATLAB实现了多阶FIR滤波器的设计,并将算法移植到DSP软件设计当中,在DSP的集成开发环境CCS下对FIR滤波进行了仿真,仿真结果达到了SDR的信道处理要求.     

自动测试系统中的智能结构

文章将智能结构的思想引入测试领域中,利用可重构技术将系统现有资源按测试要求配置为不同的结构。说明在现有技术条件下基于软件无线电技术的测试是最接近于测试智能结构。对测试设备配置为通信测试的软硬件结构做出初步研究,试验证实了系统能正确完成数据采集、数据分析和快速准确识别信号、频谱分析等设计功能。最后指出测试智能结构发展最终目标是设备与测试的融合。     

短波射频数字化接收机的设计与实现

针对传统中频数字化接收机复杂度高、灵活性差等问题,设计并实现了一种新型短波射频数字化接收机.该接收机由A/D、数字下变频器(DDC)、DSP、D/A、CPLD等几部分组成,实现了短波信号的射频数字化处理.详细介绍了接收机的设计方案,并对常见的调幅(AM)、等幅报(CW)、单边带(ISB)等信号进行了接收测试.在输入电平为-103～0 dB动态范围内,解调输出质量都能达到12 dB左右信纳得(SND).     

A software‐defined radio testbed for deep learning‐based automatic modulation classification

Automatic modulation classification (AMC) is the demodulation process on the receiver side, which is a crucial protocol for current and next‐generation intelligent communication systems. This method becomes complicated, in the presence of channel noise, to identify the modulation of the transmitted signal, that is, the transmitter and receiver with its ambiguous parameters like timing information, signal strength, phase offset, and carrier frequency. Two fundamental approaches are used for the AMC, namely, the signal statistical feature‐based approach and the maximum likelihood approach. Current Feature‐Based AMC approaches typically built for a limited set of modulation; a comprehensive AMC approach utilizing convolutional neural networks (CNN) is suggested in this article to overcome this obstacle. Altogether, 11 different types of modulations considered. In this method, without an extraction function, the transmitted signal can be identified directly. Also, the features of the received signal are known directly by using this method. The classification accuracy using CNN seems to be remarkable, especially for low SNRs. In this article, a realistic AMC framework that can be quickly applied to provide reliable efficiency in numerous commercial real‐time scenarios has developed and tested. Therefore, to prove the functional viability of our proposed model, it was applied to the software‐defined radio test‐bed.     

一种新的基于软件无线电的QAM调制信号的同步算法

在软件无线电数字通信系统中,为了基于纯软件来实现收发同步,提出了一种新的基于软件无线电的QAM调制信号的同步算法。该算法采用载波相位补偿频率偏移的思想,利用软件编程实现。另外,在DSP实现中还引用了载波系数表和帧缓存的思想,这样有助于实时性的实现。理论分析及仿真试验表明,该算法具有实用性。     

Reconfigurable filter bank structures for low complexity digital channelizer using fractional interpolation and MFIR filters with cosine modulation

A low complexity digital reconfigurable filter bank structure which is suitable for digital channelizers in software defined radio is proposed in this paper. In order to get a sharp transition width with low hardware complexity, multiplicative finite impulse response (MFIR) filter is used as the prototype filter in the proposed structure. A masking stage and a channel generation stage constitute the two stages of the proposed structure. In the masking stage, 5 sub-bands are generated by performing cosine modulation technique on the prototype filter. In the channel generation stage, different channels are generated by doing spectral addition/subtraction operations on the interpolated versions of the MFIR filter. Hence, the basic techniques used in the proposed structure are, cosine modulation and fractional interpolation technique. By adjusting a 3-bit control signal, different regions and channels, generated by the two stages, can be obtained. The proposed structure has a hardware complexity, which is much lesser than that of the state-of-the art techniques used for SDR channelizers. The number of channels generated using the proposed structure is also more. The main advantage of the proposed structure is that the hardware complexity of the proposed structure remains the same even if the number of channels is increased.     

4G技术发展的探讨

随着全球3G网络商用化的不断发展,为了满足人们对宽带数据业务传输速率的要求,研发速率更快、性能更好的新型通讯技术是相关机构和世界各国的关注问题。文章对4G通信系统的关键技术和技术目标的发展情况进行了探讨,提出4G技术的发展前景和方向,对4G通信技术在发展过程中将会遇到的问题进行了分析。     

基于AD6644和AD6620的中频信号处理平台的设计

构建了一种基于高速采样器件AD6644、可鳊程数字下变频器AD6620和高性能DSP开发板的中频信号处理平台,详细分析了它的硬件设计和软件设计。该平台具有很强的通用性和灵活性,为软件无线电技术的研究提供了一个理想的实验平台。     

SCA车载电台系统设计

车载电台系统设计,可以采用软件通信体系架构,实现灵活性、可靠性、成本控制的平衡。简述了车载软件无线电电台系统中的硬件架构和软件架构,主要阐述了系统硬件的主要设计要求,确定了车载电台系统的控制接口、系统的热设计和电磁兼容性设计的主要途径,分析了车载多通道电台的共址干扰抑制的必要性和实现技术,并基于高速总线技术、软件通信体系架构标准发展对车载电台系统进行了优化设计探索。最后探讨了车载电台未来主要的几个技术研究方向。     

基于OAI的LTE通信平台的研究与实现

文章首先介绍基于SDR(Software Defined Radio,软件定义无线电)实现的LTE开源无线通信系统—OAI(Open AirInterface的简称),重点分析OAI的软硬件平台以及OAI连接流程,通过OAIUE OAIeNB+OAI EPC/HSS实验调试与分析,采用FDD-LTE制式,实现了从EPS到eNodeB的S1接口的互连,再通过真实无线环境到UE的上下行通信。相对于其它仿真实验,可为研究LTE和相关科研教学工作人员提供一个更加符合真实应用场景的实验平台。