A method in a network node for allocating a shared radio resource to be used by a first radio unit, serving a first radio coverage area when establishing a wireless communication with a mobile station situated within the first radio coverage area, in a local radio environment comprising a plurality of radio units (110-1, 110-2, 110-3), each serving a respective radio coverage area (115-1, 115-2, 115-3), the method comprising: a planning procedure, for ranking other radio units (110-2, 110-3) comprised in the local radio environment, in order of preference for sharing the radio resource with the first radio unit when establishing the wireless communication with the mobile station, which planning procedure is performed as a preliminary allocation decision support, independently of the location of the mobile station and of the radio resource to be shared, an allocation procedure, for allocating the shared radio resource to the first radio unit when establishing the wireless communication with the mobile station, which radio resource is shared with another radio unit (110-2, 110-3) within the local radio environment, based on the ranking of radio units (110-2, 110-3), and wherein the allocation procedure is performed when the mobile station has been detected within the first radio coverage area and wherein the planning procedure of the method further comprises: estimating the mutual interference caused between the first radio unit and mobile stations (130-2, 130-3) situated in any other radio coverage areas (115-2, 115-3) comprised in the local radio environment, and/or the mutual interference caused between the other radio units (110-2, 110-3) comprised in the local radio environment and mobile station situated in the first radio coverage area, ranking the radio units (110-2, 110-3) in order of preference for sharing the radio resource to be allocated, according to the estimated mutual interference caused. a planning procedure, for ranking other radio units (110-2, 110-3) comprised in the local radio environment, in order of preference for sharing the radio resource with the first radio unit when establishing the wireless communication with the mobile station, which planning procedure is performed as a preliminary allocation decision support, independently of the location of the mobile station and of the radio resource to be shared, an allocation procedure, for allocating the shared radio resource to the first radio unit when establishing the wireless communication with the mobile station, which radio resource is shared with another radio unit (110-2, 110-3) within the local radio environment, based on the ranking of radio units (110-2, 110-3), and wherein the allocation procedure is performed when the mobile station has been detected within the first radio coverage area and wherein the planning procedure of the method further comprises: estimating the mutual interference caused between the first radio unit and mobile stations (130-2, 130-3) situated in any other radio coverage areas (115-2, 115-3) comprised in the local radio environment, and/or the mutual interference caused between the other radio units (110-2, 110-3) comprised in the local radio environment and mobile station situated in the first radio coverage area, ranking the radio units (110-2, 110-3) in order of preference for sharing the radio resource to be allocated, according to the estimated mutual interference caused. estimating the mutual interference caused between the first radio unit and mobile stations (130-2, 130-3) situated in any other radio coverage areas (115-2, 115-3) comprised in the local radio environment, and/or the mutual interference caused between the other radio units (110-2, 110-3) comprised in the local radio environment and mobile station situated in the first radio coverage area, ranking the radio units (110-2, 110-3) in order of preference for sharing the radio resource to be allocated, according to the estimated mutual interference caused.