A Study on Controlling Transmission Power of Carriers of OFDM Signal Combined with Data Symbol Spreading in Frequency Domain

Tomohiro NISHIYAMA  Tatsufumi SHIRAI  Makoto ITAMI  Kohji ITOH  Hamid AGHVAMI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E86-A   No.8   pp.2117-2124
Publication Date: 2003/08/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Communication Theory and Signals
OFDM,  power-line communication,  transmission power control,  data spreading,  

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We have already proposed a carrier power control scheme of OFDM that makes it possible to improve the bit error rate characteristic. However, the data on the lost carriers by the severe fading or large additive noise can't be recovered by only this power control scheme. In this paper, a method of transmission power control of OFDM carriers combined with data spreading scheme in the frequency domain is proposed. In the proposed system, transmission power of each carrier is controlled so as to maximize the average signal to noise ratio of the data symbols after de-spreading the signals from DFT. As the results of computer simulations, it is confirmed that the proposed system can improve the bit error rate characteristics under multi-path channel.