Error Vector Magnitude Measurement Algorithm For Vector Analytical Instrument Of Hiperlan/2

At present, 3 G communication technology has matured and in some countries to enter the operational phase. 4G communication technologies are laboratory stage. ITU (International Telecommunication Union) has not been identified 4 G standards. Hiperlan/2 technology as one of the candidate standards has excellent passive transfer rate and transfer rates with the state. Error vector magnitude (EVM): error vector (including the magnitude and phase of the missing) in a given moment no ideal base error signal and the actual launch of the vector signal worse. Hiperlan/2 test is the standard terminal signal the importance of research and development projects. RF terminal as important indicators of content, EVM indicators test the consistency of terminal equipment in research and development, quality control and production lines RF fault location, and played an irreplaceable rolefor the above considerations, based on the thesis put forward the fastest gradient algorithm conformance testing programme. Easy to implemented quickly and accurately by the EVM indicators conformance testing algorithm. The algorithm will help hiperlan/2 Standard terminal research and development and testing. And suitable used for hiperlan/2 standard terminal test instrumentation key algorithm.In the research results have been based on an iterative based on the rapid, accurate easy to realize the EVM indicators conformance testing algorithm for help hiperlan / 2 terminal of the R & D and testing, and suitable for hiperlan / 2 Terminal Test Instrument key algorithm.Error vector magnitude and the bit error rate figures are characterized modulation signal quality indicators, this paper, the relationship between the two have been studied and used computer simulation. Vector error rate and error rate in the communication system is generally part of the increase in the transmission and modulation error by the distortion of these, the majority caused by the system mechanism. Briefly speaking, they can be divided into two categories: the uncertainty and randomness. Among them, including the uncertainty of the rate distortion, phase response, multipath distortion and weak, and so linear intermediation distortion, such as two types of nonlinear distortion, which is the so-called modulation system error, the general communication system will remain basically unchanged after the set. And the increase of noise and noise by a random distortion, in an effort to simplify the model, here only to consider increasing noise in the Gaussian white noise. BER error vector and the two described digital signal modulation quality of the relationship between indicators. Demonstrated a method to the one given by the average symbol power directly calculated under different circumstances, different types of modulation EVM value, and for comparison with the corresponding BER. EVM can be seen far greater than the value of BER values. In the case of SNR, BER value of almost zero and can not be fully characterized system to signal distortion. Exceptation-Maximization algorithm used to ahead of forecasts the EVM. In the mixed model assumptions, is known as a distribution, Gaussian distribution can be mixed to approximate a wide range of distribution, in this model from the normal distribution. The corresponding distribution can also use the form that mixed up. If it can mean for a variance to 0 for normal distribution,EM algorithm and the estimated parameters of convergence, as long as the estimated weight of mixed on the distribution of Y can be estimated. And such parameters of the problem is usually estimated by the method of maximum likelihood (MLE), but this form, to direct application of maximum likelihood is more difficult.EM algorithm to estimate the proportion of mixed category is effective and simple tools. EM methods used in the paper model parameters estimated.Vector Analyzer was used to provide the basis for pre-correction. Propose a method based on Exceptation-Maximization of the error vector magnitude of the prediction algorithm. This algorithm to predict the EVM rapid change in real-time more accurately, 80 percent error control in less than six percent. So it is a reliable and effective EVM prediction algorithm.Papers design, commissioning completed in the context of the complex algorithm simulation, the simulation of a variety of modulation distortion, the indicators are stable and reliable.