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@ARTICLE{Bogena:5535,
      author       = {Bogena, H. R. and Huisman, J. A. and Meier, H. and Weuthen,
                      A.},
      title        = {{H}ybrid {W}ireless {U}nderground {S}ensor {N}etworks:
                      {Q}uantification of {S}ignal {A}ttenuation in {S}oil},
      journal      = {Vadose zone journal},
      volume       = {8},
      issn         = {1539-1663},
      address      = {Madison, Wis.},
      publisher    = {SSSA},
      reportid     = {PreJuSER-5535},
      pages        = {755 - 761},
      year         = {2009},
      note         = {We gratefully acknowledge financial support by the SFB/TR
                      32 "Pattern in Soil-Vegetation-Atmosphere Systems:
                      Monitoring, Modelling, and Data Assimilation'' funded by the
                      Deutsche Forschungsgemeinschaft (DFG).},
      abstract     = {Wireless sensor network technology allows real-time soil
                      water content monitoring with a high spatial and temporal
                      resolution for observing hydrological processes in small
                      watersheds. The novel wireless soil water content network
                      SoilNet uses the low-cost ZigBee radio network for
                      communication and a hybrid topology with a mixture of
                      underground end devices each wired to several soil sensors
                      and aboveground router devices. Data communication between
                      the end and router devices occurs partially through the
                      soil, and this causes concerns with respect to the
                      feasibility of data communication due to signal attenuation
                      by the soil. In this study, we determined the impact of soil
                      depth, soil water content, and soil electrical conductivity
                      on the signal transmission strength of SoilNet. In a first
                      step, we developed a laboratory experimental setup to
                      measure the impact of soil water content and bulk electrical
                      conductivity on signal transmission strength. The laboratory
                      data were then used to validate a semi-empirical model that
                      simulates signal attenuation due to soil adsorption and
                      reflection and transmission at the soil boundaries. With the
                      validated model, it was possible to show that in the case of
                      a soil layer of 5 cm, sufficient power will remain to ensure
                      data communication over longer distances for most soil
                      conditions. These calculations are fairly simplified and
                      should be considered as a first approximation of the impact
                      of attenuation. In actual field situations, signal
                      transmission may be more complex. Therefore, a field
                      evaluation of signal attenuation is a crucial next step.},
      keywords     = {J (WoSType)},
      cin          = {ICG-4},
      ddc          = {550},
      cid          = {I:(DE-Juel1)VDB793},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      shelfmark    = {Environmental Sciences / Soil Science / Water Resources},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000268871900022},
      doi          = {10.2136/vzj2008.0138},
      url          = {https://juser.fz-juelich.de/record/5535},
}