Patent ID: 7991057

Claim:
An apparatus for generating a ranging pseudo noise code used for a terminal of a portable internet system of an orthogonal frequency division multiple access scheme, comprising: a cell ID number search unit for detecting a cell ID number of a base station covering the terminal through a preamble signal transmitted from the base station; a ranging pseudo noise code mask value generator for generating a ranging pseudo noise code mask value depending on an offset value corresponding to a ranging mode by using the cell ID number detected by the cell ID number search unit and a system parameter provided by the base station; and a ranging pseudo noise code generator for generating a ranging pseudo noise code by performing a modulo-2 addition for an initial value and the ranging pseudo noise code mask value, the initial value including the cell ID number and the system parameter, wherein the ranging mode is selected among an initial ranging mode, a periodic ranging mode, a hand-off ranging mode, and a bandwidth request ranging mode, and wherein the system parameter includes an offset value appropriate for the ranging mode.