The memory 24 is configured to store a virtual cell index field length 28, which may be zero, one or more than one. The virtual cell index field length is determined by the virtual cell index field length determiner 18, which may be implemented by the processor 26 operating under the directions of software or may be strictly hardware as discussed above. A virtual cell determiner 30 determines a number of virtual cells configured by the network node 14. A virtual cell selector module 32 selects one of the virtual cells configured by the network node 14.

In some embodiments, the identities and corresponding indices of the configured virtual cells, if any, are signaled to the wireless device 16 by layer 3 signaling. This signaling occurs when a configuration event, such as a handover or configuration of virtual cells, occurs. The virtual cell index field length determiner 30 determines the virtual cell index field length based on the number of virtual cells configured by the network node 14. The network node 14 also includes a transceiver 34. In one embodiment, the transceiver 34 is configured to transmit the list of configured virtual cells to the wireless device 16 via L3 signaling, such as RRC signaling. Subsequently, when more than one virtual cell is configured, the DCI containing the virtual index field is also transmitted to the wireless device 16 via the transceiver 34. This index is used by the wireless device 16 to determine the virtual cell ID used to generate the pseudo-random sequence.