OFDM symbol detection over time varying channels by using sphere decoding

While being a major broadband wireless access technology, OFDM transmission over fast fading channels poses a significant challenge. Time variations in an OFDM channel destroy the sub-carriers orthogonality and complicate the problem of symbol detection. This paper considers a Sphere Decoding (SD) algorithm for OFDM over such channels. This SD algorithm is designed for banded channel matrices to reduce complexity. Then this algorithm is used for OFDM symbol detection over doubly selective wireless channels. Computer simulations results show that performance gains can be achieved over such time varying wireless channels with this OFDM detection technique. Furthermore complexity analysis results show that such an algorithm could be attractive for practical applications.