DATA TRANSMITTER AND RECEIVER USING ADAPTIVE MODULATION TECHNIQUE AND MULTI-CARRIER WAVE

摘要

PURPOSE: A data transmitter and receiver using an adaptive modulation technique and a multiple carrier are provided to guarantee a maximum transfer rate while maintaining a constant transmission quality in various environments without being affected by selective characteristics of a frequency of a transmission channel. CONSTITUTION: A serial/parallel converter(11) converts an inputted data stream to a parallel data. Data repeating and transmitting units(12A-12M) maintain a constant transmission bandwidth of the data received from the serial/parallel converter(11) against a change in the number of serial/parallel conversions and data duplications. Modulators(13A-13M) transmit data as many as and by being carried on 'S' number of sub-carriers from the data repeating and transmitting units(12A-12M) in a CDMA mode. Demodulators demodulate a signal received through a transport channel. Rake receivers compensate a multiple path fading for output data of the demodulators and obtain a path diversity. A sub-channel combiner combines data outputted from the rake receivers to obtain a frequency diversity. A hard decision unit makes a hard decision for the combined signal. A parallel/serial converter obtains data stream from data outputted from each receiver.