R.K. Martin, J.M. Walsh, and C.R. Johnson, Jr.
Submitted to IEEE Transactions on Signal Processing on October 3, 2003.
Channel shortening is often necessary for mitigation of inter-symbol and inter-carrier interference in systems employing multicarrier modulation. The MERRY algorithm has previously been shown to blindly and adaptively shorten a channel to the length of the guard interval in a multicarrier system. This paper addresses synchronization and complexity reduction issues which were not dealt with in previous work, and provides extensions to and generalizations of the MERRY algorithm. A modification is presented which removes the square root and division needed at each iteration without introducing additional complexity, with the added benefit of allowing the use of constraints other than a unit norm equalizer; an extension is proposed which allows for the use of more data in the MERRY update; the algorithm is generalized to the MIMO and fractionally-spaced cases; a low-complexity, blind symbol synchronization technique is proposed; and a method is proposed for blind initialization of the algorithm to avoid slow modes of convergence. In addition, the MERRY cost function is related to that of the per-tone LMS adaptive multicarrier equalization algorithm. Each extension to the basic MERRY algorithm is accompanied by an illustrative simulation example.