In a method of complexity reduced noise floor estimation in a wireless communications system, determining (S1), for a respective of at least a subset of a plurality of power grid points /c, a product of complementary cumulative distribution functions, each such function corresponding to a respective of a plurality j of provided wideband power measure estimates Ln a sliding window, and determining (S2), for each of said at least subset of power grid points, a probability distribution function of a minimum of said plurality of wideband power measure estimates based on said determined product.