Accton Technology Corporation

Pei-Hsuan Lin

Guu-Chang Yang

Chia-Ming Yang

A multicarrier direct-sequence code-division multiple-access (MC-DS/CDMA) communications system is provided. A code tree of two-dimensional orthogonal variable spreading factor (2D-OVSF) codes is then generated for the system. To generate the code tree, a set of existing M&#xd7;N2D-OVSF matrices, in the form of Afor i={1, 2, . . . , K} is selected as seed matrices. Mrepresents the number of available frequency carriers in the MC-DS/CDMA system, and Nrepresents a spreading factor code length. Another set of existing M&#xd7;N2D-OVSF matrices, in the form of Bfor i={1, 2, . . . , K} is then selected as mapping matrices. The mapping matrices are used to generate corresponding children matrices. These second layer child matrices are MM&#xd7;NNmatrices with cardinality KK, which are defined by reiterating the relationship: where &#x2295; indicates a Kronecker product, and i=1, 2, 3, 4, . . . , K.

Method for generating 2D OVSF codes in multicarrier DS-CDMA systems

A code tree of two-dimensional orthogonal variable spreading factor (2D-OVSF) code matrices for a multicarrier direct-sequence code-division multiple-access (MC-DS/CDMA) communications system is generated by providing two sets of 2&#xd7;2 orthogonal matrices {AA} and {BB}. The first set of 2&#xd7;2 matrices is used to generate a pair of sibling nodes in the code tree that respectively represent matrices Aand Aby iterating the relationship:

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Pei-Hsuan Lin