Parameter estimation using Maximum Likelihood estimation

I have to estimate series of transmitted signal using maximum likelihood.

Suppose, I have known data, that is received signal, say a series of vector [.04 -.2 0.23 0.54 0.9]

From this data I have to estimate tranmitted data using MLE.

But, as far I know, for normal distribution, it calculates only mean and standard deviation by using MLE.

by using mle() function for normal distribution, it output the two values, one is mean and other is standard deviation.

How can I estimate transmitted signal using MLE?