A wireless communication unit comprising a multi-user detector for use in a Code Division Multiple Access, CDMA, cellular communication system, the multi-user detector comprising: spare resource estimation means for estimating spare code resource available in the multi-user detector, wherein the spare code resource in an uplink is the difference between the maximum number of codes for the uplink and the number of intracell codes, and the spare code resource in a downlink is the difference between the maximum number of codes for the downlink and the number of codes allocated to a user equipment in the downlink; neighbour cell selection means for selecting at least a second cell neighbouring the first cell; code selection means for selecting from codes associated with the second cell at least one additional code, wherein the number of codes selected is determined by the estimated spare code resource; and wherein the code selection means comprises means for forming a first set of codes and a second set of codes and is capable of being arranged to select codes for the multi-user detector processing means with a higher priority for codes of the first set of codes than for codes of the second set of codes, and wherein in the uplink all intracell codes belong to the first set of codes and all intercell codes belong to the second set of codes, and in the downlink all codes allocated to the user equipment in the downlink are included in the first set of codes and all remaining intracell and intercell codes are included in the second set of codes; and multi-user detector processing means for performing multi-user detection processing in the first cell with the at least one additional code associated with the second cell. spare resource estimation means for estimating spare code resource available in the multi-user detector, wherein the spare code resource in an uplink is the difference between the maximum number of codes for the uplink and the number of intracell codes, and the spare code resource in a downlink is the difference between the maximum number of codes for the downlink and the number of codes allocated to a user equipment in the downlink; neighbour cell selection means for selecting at least a second cell neighbouring the first cell; code selection means for selecting from codes associated with the second cell at least one additional code, wherein the number of codes selected is determined by the estimated spare code resource; and wherein the code selection means comprises means for forming a first set of codes and a second set of codes and is capable of being arranged to select codes for the multi-user detector processing means with a higher priority for codes of the first set of codes than for codes of the second set of codes, and wherein in the uplink all intracell codes belong to the first set of codes and all intercell codes belong to the second set of codes, and in the downlink all codes allocated to the user equipment in the downlink are included in the first set of codes and all remaining intracell and intercell codes are included in the second set of codes; and multi-user detector processing means for performing multi-user detection processing in the first cell with the at least one additional code associated with the second cell.