Spreading Code Allocation

An apparatus, comprising:

• at least one processor;
• and
• at least one memory including computer program code,
• the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:
• allocating length-2n spreading codes to reference signals contained on first and second groups of resource elements in a first physical resource block and to copies of the reference signals contained on a selected group from the first or second groups and a third group of resource elements in a second physical resource block, each length-2n spreading code determined using a first length-n spreading code allocated to the first group and a second length-n code allocated to the second group, or using whichever one of the first or second length-n spreading codes is allocated to the selected group and a third length-n spreading code allocated to the third group;
• spreading symbols according to the allocated length-2n spreading codes to determine spread symbols for the reference signals and their copies;
• and
• transmitting the reference signals and their copies on the corresponding first and second groups of resource elements in the first physical resource block and the third group of resource elements in the second physical resource block.

An apparatus, comprising:

• at least one processor;
• and
• at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:
• receiving reference signals contained on first and second groups of resource elements in a first physical resource block and copies of the reference signals contained on a selected group from the first or second groups and a third group of resource elements in a second physical resource block, wherein the reference signals are spread by length-2n spreading codes allocated such that each length-2n spreading code determined using a first length-n spreading code allocated to the first group and a second length-n code allocated to the second group, or using whichever one of the first or second length-n spreading codes is allocated to the selected group and a third length-n spreading code allocated to the third group;
• and
• using at least one selected length-2n spreading code of the allocated length-2n spreading codes, despreading symbols from one or both of the reference signals or the copies of the reference signals.