In one or more embodiments, a method of processing a soft value sequence according to an iterative soft-input-soft-output (SISO) algorithm comprises carrying out sliding-window processing of the soft value sequence in a first iteration using first window placements and in a second iteration using second window placements, and varying the window placements between the first and second iterations. In at least one embodiment, a communication receiver circuit is configured to carry out iterative SISO processing, wherein it processes a soft value sequence using sliding windows, and wherein it varies window placements between one or more iterations. The communication receiver circuit comprises, for example, all or part of a turbo decoding circuit or other type of iterative block decoding circuit, an equalization and decoding circuit, a soft demodulation and decoding circuit, a multi-user detection and decoding circuit, or a multiple-input-multiple-output detection and decoding circuit.