1. A method, performed by an apparatus, for wireless communications, comprising: dividing a plurality of symbols into at least a first and a second group of symbols; preprocessing symbols in the first group to suppress interference from symbols in the second group, wherein the preprocessing utilizes a priori information for the symbols in the second group that are not yet detected; detecting symbols in the first group after preprocessing the symbols in the first group; preprocessing symbols in the second group, wherein the preprocessing utilizes a posteriori information obtained from the detected symbols in the first group; and detecting symbols in the second group after preprocessing the symbols in the second group.