Patent ID: 8750230

Claim:
A method in a base station for enabling a user equipment to transmit a configured demodulation reference signal when being served by the base station, the method comprising: assigning at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern to the user equipment, and sending at least one configuration parameter to the user equipment, said at least one configuration parameters indicating the assigned at least one of said UE-specific base sequence and UE-specific cyclic shift hopping pattern, to enable the user equipment to use said at least one configuration parameters to generate and transmit the demodulation reference signal based on the at least one of said UE-specific base sequence and UE-specific cyclic shift hopping pattern, wherein said at least one configuration parameter comprises at least one of a UE-specific base sequence parameter Δ SS,UE which the user equipment can use for determining said UE-specific base sequence and a UE-specific cyclic shift hopping parameter Δ CS,UE which the user equipment can use for determining said UE-specific cyclic shift hopping pattern, and wherein the UE-specific base sequence is determined based on a modified sequence shift pattern f SS,UE PUSCH for a PUSCH channel and the UE-specific cyclic shift hopping pattern is determined based on a modified cyclic shift random generator initialization parameter c initi,UE , and wherein said modified sequence shift pattern f SS,UE PUSCH can be determined based on the UE-specific base sequence parameter Δ SS,UE , and said modified cyclic shift random generator initialization parameter c initi,UE can be determined based on the UE-specific cyclic shift hopping parameter Δ CS,UE .