Title :
Performance evaluation of Code-Spread OFDM using Vandermonde spreading
Author :
Al-Mahmoud, Muthanna ; Zoltowski, Michael D.
Author_Institution :
Sch. of Electr. & Comput. Eng., Purdue Univ., West Lafayette, IN
Abstract :
Spectral nulls present in a channel can severely degrade or cancel out OFDM tones, resulting in an irreducible error rate. To combat this, standards typically employ forward error correction (FEC) techniques. In code-spread OFDM (CS-OFDM), each sinewave carries a weighted sum of all the information symbols being transmitted in an OFDM block interval. In this paper, the MMSE estimator is derived for each symbol for a number of cases, including when the number of carriers is greater than the number of symbols. The performance of CS-OFDM is evaluated using Hadamard and Vandermonde spreading and compared to standard OFDM1.
Keywords :
OFDM modulation; forward error correction; least mean squares methods; Hadamard spreading; MMSE estimator; Vandermonde spreading; carries information symbols; code-spread OFDM; forward error correction techniques; Convolutional codes; Degradation; Error analysis; Error correction; Error correction codes; Fading; Forward error correction; Multiaccess communication; OFDM modulation; Vectors; CS-OFDM; Code Spreading; Hadamard Spreading; OFDM; Vandermonde Spreading;
Conference_Titel :
Radio and Wireless Symposium, 2009. RWS '09. IEEE
Conference_Location :
San Diego, CA
Print_ISBN :
978-1-4244-2698-0
Electronic_ISBN :
978-1-4244-2699-7
DOI :
10.1109/RWS.2009.4957344
