An Illustration of the MAP Estimation Method for Deriving Closed-Loop Phase Tracking Topologies: The MSK Signal Structure

This paper discusses the application of MAP estimation techniques to the problem of defining tracking loops for the estimation of various signal parameters. While this method has been applied to various signal structures such as BPSK and QPSK to show the reasonableness of certain loops such as the Costas loop, it is shown that the MAP method is useful for deriving tracking structures for signals for which no previously defined tracking loops exist. The method has already been applied to the case of deriving carrier tracking loops for unbalanced quadriphase (UQPSK). The particular application chosen to illustrate the MAP technique is the MSK signal. In particular, a closed loop is derived that jointly estimates both the carrier and clock phases.