QAM

Multiple input multiple output techniques combined with orthogonal frequency division multiplexing (MIMO-OFDM) provide a promising approach for wireless systems. However, a serious drawback of the OFDM system is the high peak-toaverage power ratio (PAPR), which may severely affect the power efficiency of RF power amplifiers. In this paper, we propose a simple method to reduce the PAPR of MIMO-OFDM signals based on the use of unused subcarriers. Instead of processing the signals at each transmitter separately, a peak cancelling signal is generated at one antenna and is then applied to all the others with only simple modifications. Simulation has shown that a minimum 2 dB reduction in PAPR can be achieved for all transmit signals using this approach. As the signal processing is nearly all done at a single transmitter, repetition of the operations at each transmitter is avoided, and therefore the overall cost of the system can be significantly reduced.

cooperative relay communication ieee

WIMAX LOS NLOS TECHNOLOGY WHITEPAPER

说明：  经典无线链路预算模型，预测了在自由空间中由地形的非规则性造成的中值传输衰落。该模型适用于频段为20MHz至40GHz、路径长度为1km至2000km的情况。对于给定的传输路径，该计算机程序通过频率、路径长度、极化方向、天线高度、表面绕射率、地面有效半径和地面导电常数等参数可以确定传输损耗的大小。(Classic wireless link budget model, forecasts the in free space caused by terrain of regularity in the value decline.The model is suitable for the frequency of 20 MHZ to 40 GHZ, path length of 1 km to 2000 km.For a given transmission path, this a computer program can calculate the value of the transmission loss by frequency, path length, polarization direction, antenna height, surface diffraction, effective radius of the ground and ground conductivity constant parameters and so on.)

W5100 spi connect describe

说明：  4. 试说明卷积编解码的工作原理： (1) 使用Simulink仿真卷积编码，并用Viterbi译码的方法进行解码，其中的编码、译码全部是自己编写代码(S-Function方式)，不是调用Simulink的已有编码、译码函数。 (2) 请在加性白高斯噪声信道中，画出比特信噪比与误码率的关系曲线。(4. Try to explain the working principle of convolutional codec: (1) Simulink was used to simulate convolutional coding, and Viterbi decoding method was used for decoding. The coding and decoding were all written by oneself (s-function method), rather than calling the existing coding and decoding functions of Simulink. (2) in the additive white gaussian noise channel, please draw the curve of the relationship between bit signal-to-noise ratio and bit error rate.)

这是一个相对完整的OFDM通信系统的仿真设计，包括编码，调制，IFFT， 上下变频，高斯信道建模，FFT，PAPR抑制，各种同步，解调和解码等模 块，并统括系统性能的仿真验证了系统设计的可靠性 (OFDM full version of the source code, including coding, modulation, IFFT, Upper and lower frequency, Gaussian channel model, FFT, PAPR suppression, a variety of synchronization, demodulation and decoding module, and system performance of the omnibus simulation verify the reliability of the system design)

ZTEWelink Wireless Module Driver User Guide for WinCE-V1.2

多径条件下基于WSF的均匀圆阵幅相误差自校正(WSF-based multipath conditions of uniform circular array amplitude and phase error self-correction)

扩频通信，即扩展频谱通信(Spread Spectrum Communication)，它与光纤通信、卫星通信，一同被誉为进入信息时代的三大高技术通信传输方式。