Patent ID: 8630375
Filing Date: 2014-01-14
Classification: H04L

Abstract:
1. A method of received signal processing within a stage of a multi-stage receiver, said method comprising: receiving a stage input signal that comprises a received composite signal input to the multi-stage receiver if said stage is a first stage of the multi-stage receiver, or comprises a stage output signal from a preceding stage if said stage is not the first stage, said stage input signal containing signal contributions for two or more users; determining impairment covariance as between said signal contributions, and in dependence on a signal energy of a stage residual signal; detecting an effective symbol vector representing symbols from two or more of the signal contributions according to one or more effective symbol constellations having a reduced order as compared to actual symbol constellations used in transmission of the symbols, said stage residual signal arising from use of said effective symbol constellations, and wherein said detecting comprises performing a multi-user constrained search within a subspace of a full search space defined by all possibilities defined for said effective symbol vector by said one or more effective symbol constellations, including computing search metrics used for traversing said subspace, as a function of said impairment covariance; and outputting said effective symbol vector as a stage decision vector serving as a detection output of said stage and, if said stage is not a last stage of the multi-stage receiver, outputting a stage output signal based on said stage decision vector and said stage input signal, for input to a next stage of the multi-stage receiver.