Signal Separation and Reconstruction Method for Simultaneously Received Multi-System Signals in Flexible Wireless System

Takayuki YAMADA  Doohwan LEE  Hiroyuki SHIBA  Yo YAMAGUCHI  Kazunori AKABANE  Kazuhiro UEHARA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E95-B   No.4   pp.1085-1092
Publication Date: 2012/04/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E95.B.1085
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Cognitive Radio and Heterogeneous Wireless Networks in Conjunction with Main Topics of CrownCom2011)
Category: 
Keyword: 
Flexible Wireless System,  signal separation,  signal reconstruction,  short-time Fourier transform,  

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Summary: 
We previously proposed a unified wireless system called “Flexible Wireless System”. Comprising of flexible access points and a flexible signal processing unit, it collectively receives a wideband spectrum that includes multiple signals from various wireless systems. In cases of simultaneous multiple signal reception, however, reception performance degrades due to the interference among multiple signals. To address this problem, we propose a new signal separation and reconstruction method for spectrally overlapped signals. The method analyzes spectral information obtained by the short-time Fourier transform to extract amplitude and phase values at each center frequency of overlapped signals at a flexible signal processing unit. Using these values enables signals from received radio wave data to be separated and reconstructed for simultaneous multi-system reception. In this paper, the BER performance of the proposed method is evaluated using computer simulations. Also, the performance of the interference suppression is evaluated by analyzing the probability density distribution of the amplitude of the overlapped interference on a symbol of the received signal. Simulation results confirmed the effectiveness of the proposed method.