Receiver for receiving a combination signal that comprises two separate signal portions, wherein the receiver comprises an apparatus for deriving a complex baseband signal from the combination signal; wherein the receiver is configured to set the apparatus (710; 905) for deriving the complex baseband signal from the combination signal such that a version of the combination signal filtered with a signal-matched filter is sampled such that an output signal portion of the filter based on a first one of the signal portions is sampled essentially free of intersymbol interference, and such that the output signal portion based on the second signal portion therefore generally comprises intersymbol interferences as a consequence of a different symbol clock phase underlying this output signal portion; wherein the receiver is configured to determine a probability density function ( p N 1 ( n,k)) of a disturbance affecting a detection of transmission symbols of a first signal portion according to: p N 1 n k = ∑ λ I = 1 Λ ∑ λ Q = 1 Λ p DI, λ I k ⋅ p DQ, λ Q k ⋅ f N n − y ̅ I, λ I + j y ̅ Q, λ Q; wherein k is an instant for which the probability density function p N 1 is determined, n is a possible value, Λ is a number of domains into which the sample values obtained with an intersymbol interference-affected second signal portion are united, λ I is the index of the domains in the direction of the real axis, λ Q is the index of the domain in the direction of the imaginary axis, p DI,λ I [ k] is a probability for observing a sample value whose real part is within the domain λ I, p DQ,λ Q [ k] is a probability for observing a sample value whose imaginary part is within the domain λ Q, f N is a probability density function of a presumed noise disturbance, y I,λ I is a representative of the domain λ I along the real part axis, y Q,λ Q is a representative of the domain λ Q along the imaginary part axis, and j is the imaginary unit j = − 1. wherein the receiver comprises an apparatus for deriving a complex baseband signal from the combination signal; wherein the receiver is configured to set the apparatus (710; 905) for deriving the complex baseband signal from the combination signal such that a version of the combination signal filtered with a signal-matched filter is sampled such that an output signal portion of the filter based on a first one of the signal portions is sampled essentially free of intersymbol interference, and such that the output signal portion based on the second signal portion therefore generally comprises intersymbol interferences as a consequence of a different symbol clock phase underlying this output signal portion; wherein the receiver is configured to determine a probability density function ( p N 1 ( n,k)) of a disturbance affecting a detection of transmission symbols of a first signal portion according to: p N 1 n k = ∑ λ I = 1 Λ ∑ λ Q = 1 Λ p DI, λ I k ⋅ p DQ, λ Q k ⋅ f N n − y ̅ I, λ I + j y ̅ Q, λ Q; wherein k is an instant for which the probability density function p N 1 is determined, n is a possible value, Λ is a number of domains into which the sample values obtained with an intersymbol interference-affected second signal portion are united, λ I is the index of the domains in the direction of the real axis, λ Q is the index of the domain in the direction of the imaginary axis, p DI,λ I [ k] is a probability for observing a sample value whose real part is within the domain λ I, p DQ,λ Q [ k] is a probability for observing a sample value whose imaginary part is within the domain λ Q, f N is a probability density function of a presumed noise disturbance, y I,λ I is a representative of the domain λ I along the real part axis, y Q,λ Q is a representative of the domain λ Q along the imaginary part axis, and j is the imaginary unit j = − 1.