Power Reduction of Variable Wordlength OFDM Receiver in Time-Varying Fading Channels by Monitoring Subcarrier SNRs

Shingo YOSHIZAWA  Daichi SASAKI  Hiroshi TANIMOTO  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E99-A   No.1   pp.330-337
Publication Date: 2016/01/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E99.A.330
Type of Manuscript: PAPER
Category: Digital Signal Processing
Keyword: 
wireless communication,  variable wordlength,  OFDM,  digital signal processing circuits,  

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Summary: 
Determination of wordlength is essential for designing digital circuits because the wordlength affects system performance, hardware size, and power consumption. Variable wordlength methods that a system dynamically and effectively changes the wordlength depending on surrounding environments have been studied for power reduction in wireless systems. The conventional variable wordlength methods induce communication performance degradation when compared with a floating-point representation in time-varying fading channels. This paper discusses rapid wordlength control on packet basis and proposes a new method based on monitoring subcarrier SNRs in an OFDM receiver. The proposed method can estimate signal quality accurately and can decrease the wordlength decision errors. The simulation results have indicated that the proposed method shows better PER performance compared with the conventional methods.