随笔分类 -  Software Defined Radio

摘要:之前软体无线电sdr的课题结束了,现在念的PhD也已经转向无线局域网的研究领域,我打算把所有代码开源,基于gnuradio3.4.1的GSM探测项目。是在之前的airprobe修改的,但是支持hopping 和 上行的解调解析,同时进行过“宽带”接收的实验,验证了可行性。里边什么内容,我就不在这里过多的作介绍了。 非常感谢一起参加课题的组员,Howard Wong,zheng xiang cai 还有我的adviser prof. shaohua qin代码也比较久了,有些不记得,这一分估计没包含宽带接收部分,是用自己生产的usrp1和dbsrx作的项目系统原型。这个是对gnu的贡献,拿的是g 阅读全文
posted @ 2013-11-06 09:40 Rabbit Nick 阅读(1063) 评论(0) 推荐(0) 编辑
摘要:Software Defined Radio Challenges and Opportunities’Notes2013/3/10 Nick ChanPaper come from IEEE COMMUNICATIONS SURVEYS & TUTORIALS, VOL. 12, NO. 4, FOURTH QUARTER 2010. Software Defined Radio: Challenges and OpportunitiesAbstract—Software Defined Radio (SDR) may provide flexible, upgradeable an 阅读全文
posted @ 2013-03-10 23:08 Rabbit Nick 阅读(293) 评论(0) 推荐(0) 编辑
摘要:How to install OsmocomBBAtract :OsmocomBB is an Free Software / Open Source GSM Baseband software implementation.By using OsmocomBB on a compatible phone, you are able to make and receive phone calls, send and receive SMS, etc. based on Free Software only.Introduce :This is the project page about th 阅读全文
posted @ 2012-11-09 20:24 Rabbit Nick 阅读(893) 评论(0) 推荐(0) 编辑
摘要:PortProtocol (TCP/UDP)TitleDescriptionPort TypePort 4729udpgsmtapGSM Interface TapREGISTERED PORTwireshark use port 4729 to listening GSM protocol 阅读全文
posted @ 2012-07-16 16:56 Rabbit Nick 阅读(430) 评论(0) 推荐(0) 编辑
摘要:自相关函数维基百科,自由的百科全书跳转到: 导航, 搜索自相关函数,信号处理、时间序列分析中常用的数学工具,反映了同一序列在不同时刻的取值之间的相关程度。目录[隐藏] 1 定义 1.1 统计学 1.2 信号处理 2 自相关函数的性质 3 自相关函数举例 4 参考文献[编辑] 定义自相关函数在不同的领域,定义不完全等效。在某些领域,自相关函数等同于自协方差。[编辑] 统计学将一个有序的随机变量系列与其自身相比较,这就是自相关函数在统计学中的定义。每个不存在相位差的系列,都与其自身相似,即在此情况下,自相关函数值最大。如果系列中的组成部分相互之间存在相关性(不再是随机的),则由以下相关值方程所.. 阅读全文
posted @ 2012-05-30 15:00 Rabbit Nick 阅读(4697) 评论(0) 推荐(0) 编辑
摘要:Time Division Multiple Access (TDMA)Time Division Multiple AccessIntroductionGSM uses Time Division Multiple Acces (TDMA) as its access scheme.This is how the MS interfaces with the network. TDMA is theprotocol used on the Air (Um) Link. GSM uses Gaussian Minimum-ShiftKeying (GMSK) as its modulatio. 阅读全文
posted @ 2012-05-19 15:44 Rabbit Nick 阅读(419) 评论(0) 推荐(0) 编辑
摘要:DIFFERENTIAL ENCODINGOne of the common difficulties in communications engineering is that often the same terms are used to represent different ideas. Differential Encoding is one such term. We will describe here two common ways this term is used and unless you know these differences, they can lead . 阅读全文
posted @ 2012-05-06 22:09 Rabbit Nick 阅读(339) 评论(0) 推荐(0) 编辑
摘要:信号带宽:信号频谱的宽度,也就是信号的最高频率分量与最低频率分量之差,譬如,一个由数个正弦波叠加成的方波信号,其最低频率分量是其基频,假定为f =2kHz,其最高频率分量是其7次谐波频率,即7f =7×2=14kHz,因此该信号带宽为7f- f =14-2=12kHz。信道带宽:信道可以不失真地传输信号的频率范围。为不同应用而设计的传输媒体具有不同的信道质量,所支持的带宽有所不同。信号传输频率的最大值和最小值之差(Hz)。信道带宽则限定了允许通过该信道的信号下限频率和上限频率,也就是限定了一个频率通带。比如一个信道允许的通带为1.5kHz至15kHz,其带宽为13.5kHz,上面这个 阅读全文
posted @ 2012-04-23 18:09 Rabbit Nick 阅读(493) 评论(0) 推荐(0) 编辑
摘要:Power gain in units of dB (decibel) 1⁄4 10 log10 (Pr/Pt), the log-ratio of the power levels of the two signals.This is named after Alexander Graham Bell and can also be expressed in terms of voltages, 20 log10(Vr/Vt), as P 1⁄4 (V2/R), where watts 1⁄4 10^(dB mW/10)* 10^(-3).dBm(dB milliwatt) - relati 阅读全文
posted @ 2012-03-08 12:44 Rabbit Nick 阅读(141) 评论(0) 推荐(0) 编辑
摘要:无线网络算是计算机(CS)和电子工程(EE)的一个交叉学科。相关的会议和期刊通常没有物理生物等领域那些量化的影响因子排名。但是有一点是公认的:会议影响力远大于期刊。而会议之间也没有任何量化比较,只有人们默认的一些不成文的档次划分。我读硕士和博士期间,组里对于会议和期刊档次的划分大致如下(其中加入了一些个人分析和评价)。第一档:SIGCOMM, MobiComSIGCOMM是ACM老牌会议,其首席地位无可置疑。SIGCOMM论文录用率在10%左右,收录的论文偏重系统和协议设计,极少有理论论文。另外,每年收录的二三十篇论文中仅有1/5左右是无线网络,但这些论文的平均质量和影响力都很高。MobiC. 阅读全文
posted @ 2012-01-14 16:46 Rabbit Nick 阅读(550) 评论(0) 推荐(0) 编辑
摘要:I find a paper about GNURADIO CORE and think it is a good reference. I will use Chinese to introduce it.我会用中文主要介绍一下这个GNURADIO CORE WORK主要讲什么东西。Contents1 How the GNU Radio scheduler iscalled and what it does 12 How a thread of each block works 5内容1. GNU Radio 调度器怎样调用 和怎么工作2.每个模块的线程怎么工作1 How ... 阅读全文
posted @ 2011-11-19 12:39 Rabbit Nick 阅读(690) 评论(0) 推荐(0) 编辑
摘要:2011-10-24modify ~/gnuradio3.4.1/usrp/host/lib/usrp_basic.ccabout line 111,usrp_basic::usrp_basic (int which_board,libusb_device_handle*open_interface(libusb_device *dev),conststd::string fpga_filename,conststd::string firmware_filename) : d_udh (0), d_ctx (0),d_usb_data_rate (16000000),// SWAG, see 阅读全文
posted @ 2011-10-24 17:17 Rabbit Nick 阅读(185) 评论(0) 推荐(0) 编辑
摘要:Yesterday, I read a paper about Complex in digital communication system. I thought that was a good paper to comprehend the complex meaning in engineering. So I copied some points from this paper and made it briefer.Introduction :Quadrature signals are based on the notion of complex numbers and perha 阅读全文
posted @ 2011-10-14 09:58 Rabbit Nick 阅读(663) 评论(0) 推荐(0) 编辑
摘要:Today, I use another computer to compile gnuradio-3.3.0 and find the error. >_ class boost::weak_ptr’usrp2.cc:41:33: error: expected a type, got ‘usrp2::usrp2::usrp2’usrp2.cc:43:75: error: type/value mismatch at argument 1 in templateparameter list for ‘template class 阅读全文
posted @ 2011-10-11 09:30 Rabbit Nick 阅读(236) 评论(0) 推荐(0) 编辑
摘要:The naive digital communications layer: The first layer of the onion introduces the digital transmission of data, and discusses how bits of information may be coded into waveforms, sent across space to the receiver, and then decoded back into bits. Since there is no universal clock, issues of timing 阅读全文
posted @ 2011-10-08 09:19 Rabbit Nick 阅读(164) 评论(0) 推荐(0) 编辑
摘要:GSM: Radio interfaceOne of the main objectives of GSM is roaming. Thus, to allow for interoperability between MNs stations and disparate networks of the radio interface must be standardised. Spectrum efficiency depends on aspects of the radio interface and transmission, such as system capacity or te 阅读全文
posted @ 2011-10-02 22:05 Rabbit Nick 阅读(337) 评论(0) 推荐(0) 编辑
摘要:2011-10-02Introduce:There are two RX chennels in USRP1. It can be implementeddouble receivers by us.Abstract:Yesterday, I rewrote usrp_rx_cfile.cc to implement doublereceivers. Now, I sum up how to write a multiple antenna receivercode. I use this code to receive GSM donwlink. We can use double RXto 阅读全文
posted @ 2011-10-02 13:24 Rabbit Nick 阅读(426) 评论(0) 推荐(0) 编辑
摘要:GSM 900ARFCNUplinkDownlink1890.2935.22890.4935.43890.6935.64890.8935.858919366891.2936.27891.4936.48891.6936.69891.8936.81089293711892.2937.212892.4937.413892.6937.614892.8937.81589393816893.2938.217893.4938.418893.6938.619893.8938.82089493921894.2939.222894.4939.423894.6939.624894.8939.825895940268 阅读全文
posted @ 2011-09-22 21:04 Rabbit Nick 阅读(780) 评论(0) 推荐(0) 编辑
摘要:2011-9-21These days, I was working in Gnuradio and USRP. I always felt confuse about this development platform. Because there were not an integrated documents and it also didn’t provide any tutorials to teach you how to use it.Before we handle the signal using kinds of DSP method, I need to know wha 阅读全文
posted @ 2011-09-21 19:04 Rabbit Nick 阅读(353) 评论(0) 推荐(0) 编辑
摘要:2011-09-18今天补习C++virtual函数和纯virtual函数(pure vitural function),可以使一个类成为抽象类。一个纯virtural函数是在声明时“初始化值为0”的函数,如下所示:virtual void f() const = 0;//pure virtual function“=0”成为纯指示符(pure specifier)。纯virtual函数不提供函数的具体实现,每个派生的具体类必须重写所有基类的纯virtual函数的实现,并且提供派生类是否重写这些函数的选择权。相反,纯virtual函数并不提供函数的实现,需要派生类重写这些函数以使派生类成为具体 阅读全文
posted @ 2011-09-18 11:52 Rabbit Nick 阅读(405) 评论(0) 推荐(0) 编辑

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