Title :
Iterative Detection for OFDMA Uplink with Frequency Offsets
Author :
Ahmed, S. ; Zhang, Li
Author_Institution :
Sch. of Electron. & Electr. Eng., Univ. of Leeds, Leeds
Abstract :
In this work, we propose an iterative algorithm for the detection of transmitted symbols at the uplink of an orthogonal frequency-division multiple access (OFDMA) system. The algorithm allows distinct frequency-offsets (FO)s from each user that cause self- and multiple-access-interference. The proposed algorithm squeezes the interference of subcarrier k into 2D + 1 nearby subcarriers by preprocessing the received signal, which yields a banded structure interference matrix. This banded structure is exploited to realize a low complexity iterative soft-interference-cancellation minimum mean-squared error (SIC-MMSE) equalizer that can be used in Turbo equalization. Simulation results show that the bit-error-rate (BER) performance of the proposed algorithm outperforms existing detection algorithms and is very much close to the zero-FO frequency- domain-equalization (zero-FO-FDE) at low computational cost.
Keywords :
OFDM modulation; equalisers; error statistics; frequency division multiple access; iterative methods; least mean squares methods; radiofrequency interference; BER performance; OFDMA system; OFDMA uplink; SIC-MMSE equalizer; Turbo equalization; banded structure interference matrix; bit-error-rate; frequency offsets; iterative algorithm; iterative detection; minimum mean-squared error; multiple-access-interference; orthogonal frequency-division multiple access system; self-access-interference; soft-interference-cancellation; transmitted symbol detection; Bit error rate; Computational complexity; Detection algorithms; Equalizers; Filters; Interference; Iterative algorithms; Matrix decomposition; OFDM; Sparse matrices;
Conference_Titel :
Wireless Communications and Networking Conference, 2009. WCNC 2009. IEEE
Conference_Location :
Budapest
Print_ISBN :
978-1-4244-2947-9
Electronic_ISBN :
1525-3511
DOI :
10.1109/WCNC.2009.4917764
