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Parallel transmit technology in the clinical setting has yet to receive widespread adoption. To retrofit existing clinical systems for multi-channel transmit, dedicated hardware and a flexible, user-friendly software interface must be developed. We have designed a LabVIEW-based software system to drive an 8-channel parallel transmit system and provide a straightforward interface for the pulse designer...
Size and cost considerations of handheld terminals limit the use of antenna array for combating multipath fading in these applications. Recently, a synthetic array based on moving a single antenna was proposed for handheld terminals. This technique however fails to provide enough diversity gain when the channel is spatially correlated. A combination technique based on merging polarization and spatial...
A novel technique for synthesizing an array of antenna elements with multiple polarization characteristics based on angular movements of a single antenna is developed. The diversity performance of the synthesized antenna array is then compared to that of a single static antenna through an extensive set of measurements based on capturing the CDMA 2000 signals (transmitted from nearby base stations)...
A mobile station (MS) antenna is typically undergoing random spatial motion as part of the typical usage which degrades the coherency of the received signal resulting in demodulation losses. However, in a fading environment, the random motion can be constructively exploited in a generalized likelihood ratio test (GLRT) processing scheme resulting in diversity gain. The key outcome is the observation...
Size and cost considerations of handheld terminals limit the use of antenna array for combating multipath fading in these applications. Recently, a synthetic array based on moving a single antenna was proposed for handheld terminals. This technique however fails to provide enough diversity gain when the channel is spatially correlated. A combination technique based on merging polarization and spatial...
This paper analysis the performances of a single antenna handheld receiver in detecting a signal in a Rayleigh multipath fading environment. If the antenna is spatially fixed during the time interval that the signal is sampled then signal coherency is maintained. However, the signal will be subject to statistically large fading losses. The alternative is to spatially translate the antenna along some...
The performances of a single moving antenna receiver in detecting a narrowband signal in a correlated Rayleigh fading is considered. The single moving antenna captures spatial samples during antenna displacement that provides a realization of a synthetic antenna array. It is shown that there is a net processing gain in applying synthetic antenna array over keeping antenna stationary. This processing...
The accuracy of time of arrival (TOA) measurements is significantly compromised due to the multipath components which coexist with the desired line of sight (LOS) components in the received signal. Effective mitigation of multipath is offered by using an antenna array with beamforming capabilities. However, arrays are physically large and unwieldy from a signal processing perspective and hence not...
In this paper, a new method for AOA estimation, based on the synthetic ESPRIT algorithm is described and tested with actual CDMA signals. Physical size constraints of handheld devices typically exclude the possibility of using multiple antennas. To overcome this limitation, antenna array can be synthesized by physically moving a single antenna in an arbitrary trajectory while collecting a snapshot...
This paper describes a hybrid AOA/TODA mobile station (MS) location estimation method based on the CDMA wireless communications signals. The method utilized estimates the angle of arrival (AOA) and time difference of arrival (TDOA) of downlink pilot channel. In this paper, signal parameter estimations including AOA and TDOA, and position estimation challenges in real wireless communications systems...
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