Abstract: A method of orthogonalizing signals transmitted from a BS in an OFDMA system, at a transmitting end, includes a) performing encoding, interleaving and modulation on original information bits; b) allocating sub-carriers with equivalent intervals to a sub-channel, and dividing channels into two parts of a cell edge user channel and a center area channel; c) mapping modulated information symbols to the corresponding sub-carriers; d) performing orthogonalizing processing on the two parts of channels; e) for a user at an edge of the cell, according to result of step b), dividing an OFDM symbol into subsections of equal length; f) multiplying the subsections obtained from step e) by a corresponding orthogonalizing sequence of the cell; g) adding the OFDM symbols of the two parts together to form a whole OFDM symbol; h) adding a cyclic prefix for the system; and i) performing D/A conversion, RF processing and feedback over a transmitting antenna on a base-band signal.

Abstract: An apparatus and method for configuring a subframe to support a relay service in a multi-hop relay BWA communication system are provided, in which a first zone of a subframe is configured for at least one of communication between a BS and a first MS within the coverage area of the BS and communication between at least one RS and a second MS within the coverage area of the at least one RS, and a second zone of the subframe is configured for at least one of communication between the BS and the at least one RS and communication between the at least one RS and another RS.

Abstract: A ranging apparatus in a communication system is provided. A terminal generates a ranging code for ranging with a base station, maps the ranging code to at least one sub-carrier so the ranging code is repeated in a time domain, generates a ranging signal so the mapped ranging code has a size of one symbol interval, and transmits the generated ranging signal to the base station. The base station receives a ranging signal, extracts a half signal of a valid symbol interval of the ranging signal, generates a valid symbol interval signal by repeating the extracted half signal of the valid symbol interval, restores a ranging signal using the valid symbol interval signal, and performs ranging using the ranging signal.