Description: WLAN仿真－发送机
wlan No Comments
设置完系统参数后，开始产生发送数据。
1. 产生随机的发送bit（tx_bits），这里不考虑信道编码。
2. QAM映射
3. 将数据映射到不同载波，形成OFDM符号
4. 产生pilot，并将pilot插入OFDM符号中
5. 加入dc和guard子载波
6. 进行ifft，将频域信号变到时域，并加入循环前缀
7. 对信号进行overlap window
8. 在时域产生short preamble
9. 在时域产生long preamble
10. 将preamble和数据符号组成packet
11. 升采样
得到信道传输的数据Tx_signal_up
具体程序见附件 wlan_transmitter.m-WLAN Simulation- wlan No Comments transmitter system parameters set finished, the beginning to have to send data. 1. Have sent random bit (tx_bits), here does not consider channel coding. 2. QAM mapping 3. The data is mapped to a different carrier to form OFDM symbols 4. Have a pilot, and pilot inserted OFDM symbols 5. Adding dc and guard subcarriers 6. To carry out ifft, will change the frequency domain signal to time domain, and add cyclic prefix 7. the signals overlap window8. In the time domain have a short preamble9. In the time domain have a long preamble10. the preamble and data symbols packet11. or sampling received data transmission channel Tx_signal_up specific procedures see Annex wlan_transmitter.m Platform: |
Size: 1024 |
Author:福东方 |
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Description: this code is for Wimax(ieee standard 802.16) and other ofdm based transmitter and makes preamble for their training frames to make synchronization easier. Platform: |
Size: 1024 |
Author:amin |
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Description: OFDM系统中提出一种改进方法对频偏的捕获, 在联合使用9个短前导序列和长前导序列估计算法的基础上,采用鉴频环路的方法来消除算法中的除法和取模运算 -OFDM system in an improved way of deviation of the capture, in the joint use of nine short leader sequence and the long preamble sequence estimation algorithm, based on the frequency discriminator method to eliminate the loop algorithm in the division and modulo operation Platform: |
Size: 272384 |
Author:fy |
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Description: MIMO OFDM 技术将成为第4 代移动通信系统的关键技术, 因MIMO OFDM 对时间和频率偏移非常敏感,
因此MIMO OFDM 同步显得尤为重要。提出了一种新的MIMO OFDM 定时同步和频偏同步技术。以GCL 序列为基础设
计了一个新的符合MIMO OFDM 同步技术的导频序列, 通过对该导频序列进行2 次相关得到频率估计, 并将所得频率
运用到定时同步中, 得到更为准确的时间估计。仿真结果表明, 在相同的信噪比情况下, 该方法可以使得系统的误码
率和帧传送误码率相对传统方法得到进一步减小。-MIMO OFDM will become a key technology of the fourth generation mobile communications system. However, MIMO OFDM is
sensitive to the CFO and timing synchronization, so the MIMO OFDM synchronization technology is very important. This paper proposes an
accurate technique for timing and frequency synchronization of multiple input multiple output ( MIMO ) orthogonal frequency division
multiplexing ( OFDM) systems. The technique derives a new preamble signal based on GCL sequences, according with the MIMJO OFDM
synchronization. The carrier frequency offset ( CFO) estimation is obtained through taking double correlation operations on the preamble signal,
and used in the timing synchronization to gain accurate time estimation. The simulation results show that at the same SNR, the proposed method
can reduce the BER and the frame transmission BER of the system compared to the conventional method. Platform: |
Size: 408576 |
Author:蜡笔 |
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Description: 一种新的符号定时和载波频率同步算法,该算法将OFDM符号分成几部分。它使用相关性和积累在几个OFDM同步算法对OFDM系统基于试点,使用前言快速、准确获取信号,在有限的时间建立同步,利用导频跟踪同步信息-A new symbol timing and carrier frequency synchronization algorithm is presented and the algorithm divides the OFDM symbol into several parts. It uses correlation and accumulation in several OFDM a synchronization algorithms for OFDM system based on pilot, using the preamble to fast and accurate acquire signal, establish synchronization in the limited time, and using pilot to track synchronization information Platform: |
Size: 1267712 |
Author:wujueying |
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Description: Time Frequency Multiplex Preamble Design for Joint I1Q Imbalance, CFO and Channel Estimation in OFDM Systems
IEEE Paper Platform: |
Size: 1665024 |
Author:RITEN PATEL |
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Description: Three Timing Synchronization Methods Based on Two Same Preambles for OFDM Systems
The purpose of this paper is to propose two fast timing synchronization methods of OFDM System which has two preamble symbols, the two preamble symbols are used for SNR estimation for OFDM systems. The synchronization techniques are examined in Multipath fading environments for comparison. The results of the performance
comparison are presented in terms of mean obtained by simulations. Platform: |
Size: 268288 |
Author:Mohamed |
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Description: Time and Frequency Synchronization Techniques for
OFDM Systems operating in Gaussian and Fading
Channels: A Tutorial
The aim of this paper is to survey and compare
previous methods for Data-aided timing and frequency
synchronization of OFDM System. In the sequel, we propose a fast
and accurate FFT-based frequency offset estimation. The
synchronization techniques are examined in Gaussian andMultipath fading environments for comparison. The results of the
performance comparison are presented in terms of mean andmean-square error (MSE) obtained by simulations. The timing
offset estimator with best performance is chosen for system timingsynchronization. The FFT-based frequency offset estimation
method has significantly smaller MSE than others can beperformed using the same timing training symbol. Therefore,there is only one training symbol needed as preamble in whole
synchronization process.
Platform: |
Size: 340992 |
Author:Mohamed |
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Description: Frequency Synchronization in OFDM System
An accurate frequency synchronization method using the zadoff-chu (ZC) constant envelop preamble is analyzed, and a new preamble weighted by pseudo-noise sequence is used for orthogonal frequency division multiplexing (OFDM) systems. Using this method, frequency offset estimator range is greatly enlarged with no loss in accuracy. The range of the frequency estimation is ±30 of subcarrier spacing using ZC sequence as preamble. Simulations in the MATLAB for an AWGN channel show that the proposed method achieves superior performance to existing techniques in terms of frequency accuracy and range. Platform: |
Size: 349184 |
Author:Mohamed |
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Search - preamble in ofdm