A method performed by a wireless device (14, 200) configured for use in a wireless communication system, the method comprising: • receiving reference symbols of a tracking reference signal, TRS, on respective radio resources, including first and second sets (S1, S2) of radio resources that differ in at least one radio resource, wherein the first set of radio resources includes a first pair of radio resources that are separated from one another in a radio resource domain by a first separation distance, with no reference symbol of the reference signal on any radio resource between the first pair of radio resources in the radio resource domain, and wherein the second set of radio resources includes a second pair of radio resources that are separated from one another in the radio resource domain by a second separation distance, with no reference symbol of the reference signal on any radio resource between the second pair of radio resources in the radio resource domain, wherein the second separation distance is at least twice as large as the first separation distance, • wherein the radio resource domain is a time domain or a frequency domain, • wherein the first set of radio resources is a subset of the second set of radio resources, • the method further comprises performing frequency estimation in two steps, wherein in a first step, a first frequency is estimated based on reference symbols of the first set of radio resources, and in a second step, a second frequency is estimated based on references symbols of the second set of radio resources and the first frequency estimate, • radio resources on which the reference signal is received occur in periodically recurring TRS bursts, wherein the first slot in the TRS burst has high TRS density, with OFDM symbol spacing 2 between consecutive TRS symbols, and following slots in the TRS burst have lower TRS density, wherein a configuration of the periodically recurring TRS bursts is based on whether the wireless device (14, 200) is in active-mode or in discontinuous reception, DRX, mode. • receiving reference symbols of a tracking reference signal, TRS, on respective radio resources, including first and second sets (S1, S2) of radio resources that differ in at least one radio resource, wherein the first set of radio resources includes a first pair of radio resources that are separated from one another in a radio resource domain by a first separation distance, with no reference symbol of the reference signal on any radio resource between the first pair of radio resources in the radio resource domain, and wherein the second set of radio resources includes a second pair of radio resources that are separated from one another in the radio resource domain by a second separation distance, with no reference symbol of the reference signal on any radio resource between the second pair of radio resources in the radio resource domain, wherein the second separation distance is at least twice as large as the first separation distance, • wherein the radio resource domain is a time domain or a frequency domain, • wherein the first set of radio resources is a subset of the second set of radio resources, • the method further comprises performing frequency estimation in two steps, wherein in a first step, a first frequency is estimated based on reference symbols of the first set of radio resources, and in a second step, a second frequency is estimated based on references symbols of the second set of radio resources and the first frequency estimate, • radio resources on which the reference signal is received occur in periodically recurring TRS bursts, wherein the first slot in the TRS burst has high TRS density, with OFDM symbol spacing 2 between consecutive TRS symbols, and following slots in the TRS burst have lower TRS density,