Through-wall UWB Communications with Limited Transmit Power

This paper derives the lower bound expression for the transmit power utilizing outage probability criterion. The design is applied to a communication system that transmits sensor data in a nuclear power plant through concrete wall using ultra-wideband (UWB) communications with center frequency of 915 MHz (815 MHz to 1 GHz). In this paper, Orthogonal Frequency Division Multiplexing (OFDM) modulation along with water filling (WF) algorithm is used. Since the transmit side has power limitation, a Single Input Multiple Output (SIMO) design is introduced to optimize transmit power requirement. The performance of this system is compared with Single Input Single Output (SISO) together with WF technique and different constant QAM constellations using OFDM modulation. Our approach demonstrates 46% data rate improvement compared to SIMO system using the same transmit power. Further, our simulations show up to 82.9% reduction in power consumption compared to SISO system utilizing water filling algorithm. The proposed approach also outperforms systems utilizing same QAM constellation for all the OFDM subchannels.