Question

求助在线翻译~~~

The problem of joint maximum-likelihood estimation of the carrier-frequency offset (CFO) and channel coefficients in multiple-input multiple-output orthogonal frequency-division multiplexing systems is investigated, assuming that a training sequence is available. The exact solution to this problem turns out to be too complex for practical purposes. To overcome this difficulty, the authors resort to the expectation-maximisation (EM) algorithm and propose an iterative scheme which iterates between estimating the channel parameters and the frequency offset. This results in an estimation algorithm of a reasonable complexity which is suitable for practical applications. Moreover, the Cramer-Rao bounds (CRB) for both CFO and channel estimators are developed to evaluate the performance of the proposed scheme. Simulation results show that the proposed algorithm achieves almost ideal performance compared with the CRBs in all ranges of signal-to-noise ratio for both channel and frequency offset estimates.

Answer 1

这个问题的联合最大似然估计的载波频率偏移（首席财务官）和通道系数的多输入多输出正交频分复系统的调查，假设一个训练序列可用。确切的解决这一问题的办法却是过于复杂，实际的目的。为了克服这一困难，作者度假的期望，争取最高（ EM ）算法，并提出一种迭代计划，遍历估计之间的通道参数和频率偏移。这样的结果是一个估计算法的一个合理的复杂性，适合于实际应用。此外，克莱默娆界（ CRB指数）为首席财务官和渠道估计的发展业绩考核评价这项计划。仿真结果表明，该算法达到了理想的业绩与CRBs在所有范围内的信号噪声比两个频道和频率偏差估计。

Answer 2

Answer 3