In a radio access network (10) comprising a radio network controller node (26) and a base station node (28), a code tree has spreading codes which are allocatable between high speed downlink shared (HS-DSCH) channels and dedicated (DCH) channels. According to one aspect of the technology, use of the spreading codes of the code tree is monitored and an HS-DSCH channel is allocated a free spreading code which is non-adjacent to a spreading code already allocated to the HS-DSCH channels. In some example implementations, the free, non-adjacent spreading code is allocated so that more than one high speed channel user can use the spreading codes. In other example implementations, the free, non-adjacent spreading code is allocated so that one user uses the spreading codes by using more than one HS-SCCH channel. Preferably the non-adjacent spreading code is released from the HS-DSCH channel when the non-adjacent spreading code is needed for use by a DCH channel.