| Summary: | 碩士 === 國立交通大學 === 電機學院IC設計產業專班 === 95 === For channel modeling of UWB SISO BAN, it is found that the diffracted wave is the dominant propagation path in the open space observed from the temporal response. However, when the Rx places on the back of the body that is surrounded by dense local scatterers, the scattering due to the local scatterers becomes the dominant propagation mechanism and the received signal strength is much larger than that of without local scatterers. Therefore, the path loss exponent in the room with dense local scatterers is smaller than that in open space. The AIC indicates that the Lognormal distribution is the best one in modeling the small scale fading distribution.
For MIMO BAN measurement, the capacity of Rx antenna array elements placed on the back of the body is higher than that placed on the front of the body. This is due to the received signal obstructed by the body, which yields reduction of the spatial channel correlation at the Rx antenna. The influence of environment on the capacity of BAN MIMO system is not significant. However, the capacity of Rx placed on the front of the body is more easy affected by the local environment than that placed on the back of the body. It is found that the capacity of the MIMO BAN decreases as the element spacing increases. It is because that although the increasing element spacing may reduce the correlation of Rx or Tx and leads capacity increase, the signal strength of the subchannel decreases a lot due to large diffraction loss and yields little contribution of the subchannel. Therefore, element spacing increases may not contribute to the MIMO channel capacity.
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