Method and apparatus for generating non-recursive variable rate orthogonal spreading codes

A method comprising:

• defining a variable B=SFmax/SFmin, where SFmax is a maximum desired spreading factor and SFmin is a minimum desired spreading factor, where SFmax and SFmin are integer values;
• forming B unique base matrices Gk of dimension SFmin×SFmin, where GiGiT=SFminImin ∀i, where T denotes a matrix transpose and Imin is an SFmin×SFmin identity matrix;
• forming a modulation matrix M of dimension B×B such that MMT=BIB, where IB is a B×B identity matrix;
• forming an SFmax×SFmax orthogonal variable spread factor (OVSF) code matrix C′ as:
• C
• ′
• =
• [
• M
• 1
• ,
• 1
• ·
• G
• 1
• M
• 1
• ,
• 2
• ·
• G
• 2
• …
• M
• 1
• ,
• B
• ·
• G
• B
• M
• 2
• ,
• 1
• ·
• G
• 1
• M
• 2
• ,
• 2
• ·
• G
• 2
• …
• M
• 2
• ,
• B
• ·
• G
• B
• ⋮
• ⋮
• ⋰
• ⋮
• M
• B
• ,
• 1
• ·
• G
• 1
• M
• B
• ,
• 2
• ·
• G
• 2
• …
• M
• B
• ,
• B
• ·
• G
• B
• ]
• ,
• where Mi,j is a scalar from the i-th row and j-th column of the modulation matrix M, Gl . . . GB is the k-th base matrix Gk and Mi,j·Gk denotes the multiplication of the elements of Gk by the scalar Mi,j, where i, j and k are integer values;
• selecting a row of the OVSF code matrix C′ to use as a pseudo-noise (PN) code;
• and
• one of spreading or despreading a signal using the selected PN code, where the steps of defining, forming the B unique base matrices, forming the modulation matrix M, forming the OVSF code matrix C′, selecting and one of spreading or despreading are performed by at least one processor.