Enhanced PHY symbol structure based on the IEEE 802.15.4a standardization and orthogonal pulses for 3D positioning

According to IEEE 802.15.4a standardization, an ultra wideband PHY symbol is capable of carrying two bits of information and only one pulse shall be transmitted in each symbol. To prevent inter symbol interference caused by multipath effect, the guard interval is present between the possible burst positions. In order to make full use of the symbol for estimating the azimuth and the elevation of target, we can add additional information at the guard interval position, if the pulse used at the possible burst position is different from the pulse used at the guard interval position. Using the orthonormality between the multiple pulses, furthermore, inter symbol interference can be avoided at the correlation receiver. In this paper, as the first step for estimating the azimuth and the elevation information, we propose a novel PHY symbol structure for IR-UWB system based on IEEE 802.15.4a standardization and orthogonal pulses to enhance the data rates without the bit-error-rate (BER) performance degradation. In the proposed scheme, the pulse used at the possible burst position is the modified hermite polynomial (MHP) pulse of order n equal to 3 and the pulse used at guard interval position is the MHP pulse of order n equal to 4. The performance of the proposed structure is evaluated by computer simulations over the IEEE 802.15.4a channel model. Simulation results show that the proposed symbol structure with orthogonal pulses can double the data rates of the systems without BER performance degradation.