| 摘要 |
A data communication apparatus and method based on orthogonal frequency division multiple access (OFDMA) are provided. In the data communication apparatus, a (U+1)-th encoder in a u-th user transmitting unit among U user transmitting units which transmit corresponding user information to a base station part encodes the user information and outputting the result of encoding as N<SUB>u </SUB>u-th user symbols. A user signal generator generates a u-th user signal x<SUB>k</SUB><SUP>(u) </SUP>in a temporal domain from the u-th user symbol A<SUB>m</SUB><SUP>(u) </SUP>received from the (U+1)-th encoder according to a formula, x<SUB>k</SUB><SUP>(u)</SUP>=a<SUB>k % N</SUB><SUB><SUB2>u</SUB2></SUB><SUP>(u) </SUP>exp(j2pikn<SUB>u</SUB>/N). A second cyclic extension symbol inserter inserts a cyclic extension symbol into the u-th user signal. A second signal transmitter converts the result of insertion into a symbol block signal and transmitting the symbol block signal to the base station part. Here, 1<=N<SUB>U</SUB><N. Accordingly, the hardware of a user part can be optionally simplified very much. Communication efficiency can be increased in a given channel environment. In addition, different types of user parties having different complexities can communicate with a base station part using a single data format.
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