TRANSMISSION OF DIGITAL SIGNALS BY ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING

摘要

In an orthogonal frequency division multiplexing (OFDM) system (10) which uses an outer Reed-Solomon encoder and interleaver (24) and an inner convolutional encoder (26), after the inner convolutional encoding the data bits are interleaved by an inner interleaver (28), and then grouped into symbols, each symbol having "m" bits. After grouping, the symbols are mapped to a complex plane using quadrature amplitude modulation (QAM). Thus, bits, not symbols, are interleaved by the inner interleaver (28). A receiver (12) performs a soft decision regarding the value of each bit in each complex QAM symbol received.