Examination of Effective UWB Avoidance Based on Experiments for Coexistence with Other Wireless Systems

Huan-Bang LI  Kunio YATA  Kenichi TAKIZAWA  Noriaki MIYAZAKI  Takashi OKADA  Kohei OHNO  Takuji MOCHIZUKI  Eishin NAKAGAWA  Takehiko KOBAYASHI  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E96-A   No.1   pp.274-284
Publication Date: 2013/01/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E96.A.274
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Wideband Systems)
Category: 
Keyword: 
UWB,  interference avoidance,  subcarrier nullification,  notch,  clearance spacing,  

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Summary: 
An ultra-wideband (UWB) system usually occupies a large frequency band, which may overlap with the spectrum of a narrow band system. The latter is referred to as a victim system. To effectively use frequency, a UWB system may create a notch in its spectrum to accommodate the victim signal for interference avoidance. Parameters of the notch such as the depth and the width of a notch need to be decided in accordance to victim systems. In this paper, we investigate the effective UWB avoidance by examining the suitable notch based on experimental evaluation. In the experiments, 3GPP LTE, Mobile WiMAX, as well as an IMT Advanced Test-bed are respectively employed to represent different types of victim systems. The UWB system is set up based on WiMedia specifications and operates at the UWB low band of 3.1–4.8 GHz. A notch is fabricated by nullifying the related subcarriers of the UWB signal. In addition, a filter or a window function is formed and employed to further smooth the notch. Bit error rate (BER) or packet error rate (PER) performances of victim systems are measured and used to evaluate the UWB interference. Our results show that when a notch is properly formed, the interference level introduced by UWB can be below the permitted level by regulations.