[通讯编程] auto_filter
自适应滤波器作为一种现代滤波器，在通信领域有着广泛的应用. 阐述了LMS以及RLS自适应滤波器的相关原理及其在通信系统去噪中的应用，并用MATLAB对自适应滤波器的去噪结果进行了相应的仿真，仿真结果直观地体现了自适应滤波器的去噪性能。
本文对自适应滤波器系统进行剖析，基于QPSK调制后的信号，并对该信号加工成为不同信噪比如SNR=0Db、SNR=5dB、SNR=10dB的信号，进行了两种分别基于LMS自适应滤波和RLS自适应滤波的操作。并对添加了有色高频噪声等加噪处理来模拟通信过程中的实际应用环境，测试所设计的低通滤波器对于噪声信号的滤波性能，并对结果进行分析总结。
As a modern filter, adaptive filter has a wide range of applications in the field of communication. This paper expounds the relevant principles of LMS and RLS adaptive filter and their applications in the de-noising of communication system, and simulates the de-noising results of adaptive filter with MATLAB. The simulation results directly reflect the de-noising performance of adaptive filter.
In this paper, the adaptive filter system is analyzed, based on the QPSK modulated signal, and the signal is processed into different signal-to-noise, such as SNR = 0dB, SNR = 5dB, SNR = 10dB signal. Two kinds of operation are carried out based on LMS adaptive filtering and RLS adaptive filtering respectively. In order to simulate the practical application environment in the communication process, we add colored high-frequency noise to test the filtering performance of the designed low-pass filter for noise signal, and analyze and summarize the results. (2021-02-01, matlab, 3KB, 下载3次)
[通讯编程] OFDM submit
本文设计了一个基于IFFT/FFT算法与802.11a标准的OFDM系统，并在计算机上进行了仿真和结果分析。重点在OFDM系统设计与仿真，在这部分详细介绍了系统各个环节所使用的技术对系统性能的影响。在仿真过程中对OFDM信号使用QPSK调制，并在AWGN信道下传输，最后解调后得出误码率。整个过程都是在MATLAB环境下仿真实现，对ODFM系统的仿真结果及性能进行分析，通过仿真得到信噪比与误码率之间的关系，为该系统的具体实现提供了大量有用数据。
In this paper, an OFDM system based on IFFT / FFT algorithm and 802.11a standard is designed and simulated on computer. The emphasis is on the design and Simulation of OFDM system. In this part, the influence of the technology used in each link of the system on the system performance is introduced in detail. In the simulation process, the OFDM signal is modulated by QPSK and transmitted in AWGN channel. Finally, the bit error rate is obtained after demodulation. The whole process is simulated in Matlab environment. The simulation results and performance of ODFM system are analyzed. The relationship between SNR and BER is obtained through simulation, which provides a lot of useful data for the specific implementation of the system. (2020-11-12, matlab, 346KB, 下载2次)
[通讯编程] MIMO1
实现基于STBC的MIMO_OFDM通信系统在不同信噪比情况下接收端的误比特率的仿真。发射端包括基于基带调制、空时编码、导频插入、IFFT、串并合并以及添加循环前缀；接收端包括去除循环前缀、取出导频估计信道、FFT运算以及并串合并，空时解码等。仿真中采用QPSK、空时编码采用4*3的复正交空时编码矩阵。OFDM子载波数为100，每个子载波传输66个符号，每个符号2比特。IFFT长度为512个符号。发射天线为3个接收天线为2个。
The BER simulation of MIMO_OFDM communication system based on STBC under different SNR is realized. The transmitter includes baseband modulation, space-time coding, pilot insertion, IFFT, serial-parallel combination and adding cyclic prefix; the receiver includes removing cyclic prefix, extracting pilot estimation channel, FFT operation, parallel-serial combination, space-time decoding, etc. The complex orthogonal space-time coding matrix is used in QPSK and space time coding in 4*3. The number of OFDM subcarriers is 100, and each subcarrier transfers 66 symbols with 2 bits per symbol. IFFT is 512 symbols in length. The transmitting antenna is 3 receiving antennas, 2. (2018-08-12, matlab, 3KB, 下载32次)
[通讯编程] DQPSK
(1)建立DQPSK调制和解调 SIMULINK仿真模型，评估其在AWGN信道和瑞利衰落信道下的误码率性能（画出信噪比变化时的误码率曲线）；
(2)基于（1）建立的SIMULINK仿真模型，分别在AWGN信道和瑞利衰落信道下发送一个实际音频文件，在接收端实时播放出来
(1) the DQPSK modulation and demodulation SIMULINK simulation model is established to evaluate the bit error rate performance under the AWGN channel and the Rayleigh fading channel (the bit error rate curve when the signal to noise ratio changes).
(2) based on the (1) established SIMULINK simulation model, a real audio file is sent under the AWGN channel and the Rayleigh fading channel respectively, and it is played on the receiving end in real time. (2018-04-28, matlab, 779KB, 下载23次)
[通讯编程] OLA_OOPSim
Opportunistic Large Array 的MATLAB 模拟器.
Object oriented
Event Based
无线广播
支持OLA
累积Relay重发信号以达到最佳解码效果
节点位置可随机或以网格生成
可控制调变方式
独立节点间无线传输信道模型
可调随机生成信噪比范围
生成显示各节点位置图
生成各节点接收所需OLA副本数量图
生成各节点误码率图
生成各节点HOP-COUNT图
生成各节点成功接收SYMBOL数量图
以main.m打开运行
Opportunistic Large Array Simulator in MATLAB.
Object oriented
Event Based
Wireless broadcast
Support OLA
Accumulate the signal re-transmitted from relay to maximize decoding performance
Position of nodes can be randomly or grid based initialized
Modulation methods can be changed
Independent node-to-node wireless transmission channel model
Randomly generate noise for each channel with limited SNR range
Generate nodes position diagram
Generate nodes diagram for required copies of OLA symbol to decode
Generate nodes diagram for BER
Generate nodes diagram for hop-count
Generate nodes diagram for successful decoded symbols
Run with main.m (2013-08-22, matlab, 20KB, 下载7次)
[通讯编程] OFDM-based-precise-ranging-technique
根据OFDM的时频特性,提出了一种新的空间测距方法.首先在时域对OFDM信号进行相关处
理,得到距离的粗估计,在粗估计的基础上,利用OFDM不同子载波数据之间的相位差,得到距离的精
确估计,根据精确估计的结果对粗估计的结果进行校正,从而得到最终的距离估计值.仿真结果表明,该
方法的测距精度比采用延迟锁定环的伪码测距方法至少提高了4倍,并且在信噪比大于20 dB时,可以
达到厘米级.
According to the properties of OFDM in the time and frequency domains, a novel ranging
method in space is proposed. The coarse estimation of range can be obtained from the correlation of the
waveforms of OFDM signals in the time domain, and the fine estimation is obtained from the phase
differences between the sub-carriers in the frequency domain. The fine estimation is then adopted to
correct the coarse estimation, and the final estimation of range is achieved. Simulation results show that
the ranging accuracy of the proposed method is more than 4 times better than that of pseudo-code
ranging. Furthermore, the ranging accuracy is close to the centimeter level when the signal-to-noise ratio
is beyond 20 dB.
(2012-11-02, matlab, 55KB, 下载41次)
[通讯编程] OQAM_OFDM_Perfect
本代码介绍了OFDM/OQAM 多径信道下，理想信道估计的系统仿真，给出了不同信噪比下的ber性能。介绍了多载波系统的均衡。
This code describes the OFDM/OQAM multipath channel, system simulation, ideal channel estimation, given the ber performance under different signal to noise ratio. The equilibrium of the multi-carrier system. (2012-06-19, matlab, 3KB, 下载569次)
[通讯编程] 123
针对MIMO-OFDM系统中期望最大化(EM)信道估计算法在高信噪比(SNR)下带来的误差地板(EF)现象,且OFDM符号的数据传输效率随发射天线数的增加而明显降低,提出一种改进的高效EM信道估计算法。该算法首先引入一种准确的等效信号模型并推导出一种修正的EM算法,改善了EM算法在高SNR下的性能 在多个OFDM间利用相位正交导频序列来提高数据传输效率,同时进行联合信道估计以提高估计性能。仿真实验验证了所提算法具有更高的信道估计性能和更高的数据传输效率。
For multiple-input multiple-output with orthogonal frequency division multiplexing(MIMO-OFDM) systems,the error floor(EF) phenomenon at high signal noise rate(SNR) was induced by the expectation maximum(EM) channel estimation algorithm.In addition,the data transmission efficiency was declined obviously with the increasing number of transmit antennas.According to these problems,an improved and efficient EM channel estimation algorithm was pro-posed.Firstly,an accurate and equivalent signal model was introduc... (2011-09-05, matlab, 770KB, 下载59次)
[通讯编程] MIMO_OFDM
基于期望最大化(EM)的最大后验信道估计算法(MAP)在高信噪比(SNR)下将很难获得较低的估计误差,并且,对于导频辅助的MIMO-OFDM系统,OFDM符号的数据传输效率随着发送天线的增加而明显下降.为改善这两种缺陷,引入一种等效的信号模型来改善高SNR下的估计性能 在相邻多个OFDM符号内使用相移正交导频序列和联合估计来提高系统的数据传输效率和估计性能 根据角域内信道间的独立性来减小噪声对估计的影响.通过仿真实验可知,所提算法具有更小的估计误差和更高的数据传输效率.
Maximum a posteriori(MAP) channel estimation algorithm usually uses expectation maximum(EM) algorithm to decrease the high computation.However,this kind of operation has a difficulty in obtaining ideal estimation performance at high signal to noise ratio(SNR) because of the convergent feature of EM algorithm.In addition,for pilot-based multiple-input multiple-output with orthogonal frequency division multiplexing(MIMO-OFDM) systems,data transmission efficiency of OFDM symbol will be reduced with the increas... (2011-09-05, matlab, 131KB, 下载86次)
[通讯编程] OFDM-Channel-Estimation-Based-on-Comb-Pilot
基于导频的ＯＦＤＭ系统信到估计的ＭＡＴＬＡＢ源代码，里面有详细的注释说明
Pilot-based OFDM system, the letter to the estimated MATLAB source code, which has detailed notes (2007-09-18, matlab, 3KB, 下载603次)
[通讯编程] ldpc_decoder
采用Log-BP算法的LDPC码译码仿真程序，给出了不同信噪比下误码率和误包率的统计图，用matlab和C（c-mex）程序分别编写，有详细说明和注释。
The use of Log-BP decoding algorithm for LDPC code simulation program is given a different signal to noise ratio and bit error rate under the packet error rate of the statistical map, using matlab and C (c-mex) procedures, respectively, to prepare, has a detailed description and notes . (2007-07-30, matlab, 76KB, 下载448次)