Center for Communications and Signal Processing Reserach


	Multi-Carrier
	Turbo Coding
	UWB
	Channel Estimation
	MIMO Systems
	Modulation Classification
	Information Theory
	Cooperative Communications

Power Spectral Requirements and Implementation

Faculty: Dr. A. M. Haimovich

Students: H. Sheng


Impulse radio is one of the popular choices for UWB transmission because of its ability to resolve multipath, as well as the relatively low implementation complexity associated with carrierless (baseband) pulses. Impulse radio does not use a sinusoidal carrier to shift the signal to a higher frequency, but instead communicates with a baseband signal composed of subnanosecond pulses. Because of the short duration of the pulses, the spectrum of the UWB signal can be several gigahertz wide. We analyze the transmission range as a function of data rate using a new pulse shape that meets the FCC regulations. This fifth derivative of the Gaussian pulse can be implemented by a 4th order Chebychev highpass filter. It is shown that UWB can be a good candidate for high rate transmission over short ranges, with the capability for reliably transmitting 100 Mbps over distances at about 10 m.


Figure: FCC mask and the spectrum of the 5th derivative of the Gaussian pulse.

References:
H. Sheng, P. Orlik, A. Haimovich, L. Cimini, and J. Zhang, "On the Spectral and Power Requirements for Ultra-Wideband Transmission," IEEE International Conference on Communications (ICC), Vol. 1, pp. 738-742, May 2003





Optimum Combining Rake UWB Receivers

Faculty: Dr. A. M. Haimovich
Students: H. Sheng

The application of reduced-rank adaptive filtering techniques is presented to the problem of interference suppression in ultra-wideband (UWB) communications. It is shown that reduced-rank optimum combining methods are effective in suppressing interference modeled as 802.11a signals. Simulation results are presented to show that the EC requires a shorter data record than minimum mean square error (MMSE) Rake receivers.

References:
H. Sheng, A. Haimovich, A. Molisch, and J. Zhang, "Optimum combining for time hopping impulse radio UWB rake receivers," to be presented in IEEE Conference on Ultra Wideband Systems and Technologies, Nov. 2003