A New Transceiver for OFDM Systems Using Smooth Local Trigonometric Transforms

Qing CHANG  Yongbo TAN  Wei QI  Dirong CHEN  

IEICE TRANSACTIONS on Communications   Vol.E92-B   No.2   pp.662-665
Publication Date: 2009/02/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.662
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
OFDM,  bell-shaped window function,  LTT,  folding,  DCT-IV,  

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This letter proposes a new transceiver for OFDM systems based on Smooth Local Trigonometric Transform (LTT). In our transceiver, the transmitter is realized by first modulating the original serial data using a constellation mapper, then feeding the results into the inverse LTT modulator. Unlike the conventional DFT-OFDM system, which always uses the roll cosine function as its window function, the proposed system needs no additional window function for the reason that LTT transform includes a bell-shaped window function by itself. Moreover, each LTT-OFDM symbol has a much more rapid attenuation rate outside of the spectral bandwidth and better spectrum convergence. In the receiver, the original data is recovered by demodulating the received data using forward LTT. Comparative simulation results from the conventional DFT-OFDM system, the system we proposed, and the recently proposed DCT based OFDM system are discussed in terms of bit error rate (BER).