A method performed in a network node for allocating uplink reference signal resources, the network node being capable of uplink frequency selective scheduling and combined cell configuration, the network node further being arranged to provide wireless communication to a communication device , the method comprising: - configuring , when both uplink frequency selective scheduling and the combined cell configuration are enabled, a communication device for which uplink frequency selective scheduling is enabled with resources from a second set of resources and configuring other communication devices with resources from a first set of resources, - setting configuration parameters for the first set of resources in accordance with requirements of the combined cell configuration, and setting configuration parameters for the second set of resources in accordance with requirements of the uplink frequency selective scheduling, - allocating uplink reference signal resources from the first set of resources or the second set of resources to the communication devices according to the configuration, - determining that a communication device configured for use of the first set of resources should be enabled for uplink frequency selective scheduling and reconfiguring the communication device for use of the second set of resources, and - determining that a communication device configured for use of the second set of resources fails to fulfil a criterion for use of frequency selective scheduling and reconfiguring the communication device for use of the first set of resources; wherein the determining that a communication device configured for use of the first set of resources should be enabled for uplink frequency selective scheduling comprises - estimating a performance gain of using uplink frequency scheduling to be above a threshold value, the performance gain being estimated based on number of sectors of the combined cell selected by the communication device . - configuring , when both uplink frequency selective scheduling and the combined cell configuration are enabled, a communication device for which uplink frequency selective scheduling is enabled with resources from a second set of resources and configuring other communication devices with resources from a first set of resources, - setting configuration parameters for the first set of resources in accordance with requirements of the combined cell configuration, and setting configuration parameters for the second set of resources in accordance with requirements of the uplink frequency selective scheduling, - allocating uplink reference signal resources from the first set of resources or the second set of resources to the communication devices according to the configuration, - determining that a communication device configured for use of the first set of resources should be enabled for uplink frequency selective scheduling and reconfiguring the communication device for use of the second set of resources, and - determining that a communication device configured for use of the second set of resources fails to fulfil a criterion for use of frequency selective scheduling and reconfiguring the communication device for use of the first set of resources; wherein the determining that a communication device configured for use of the first set of resources should be enabled for uplink frequency selective scheduling comprises - estimating a performance gain of using uplink frequency scheduling to be above a threshold value, the performance gain being estimated based on number of sectors of the combined cell selected by the communication device . - estimating a performance gain of using uplink frequency scheduling to be above a threshold value, the performance gain being estimated based on number of sectors of the combined cell selected by the communication device . <EOS>